Project Gutenberg's Twentieth Century Inventions, by George Sutherland

This eBook is for the use of anyone anywhere at no cost and with
almost no restrictions whatsoever.  You may copy it, give it away or
re-use it under the terms of the Project Gutenberg License included
with this eBook or online at www.gutenberg.net


Title: Twentieth Century Inventions
       A Forecast

Author: George Sutherland

Release Date: February 10, 2010 [EBook #31243]

Language: English

Character set encoding: ISO-8859-1

*** START OF THIS PROJECT GUTENBERG EBOOK TWENTIETH CENTURY INVENTIONS ***




Produced by Chris Curnow and the Online Distributed
Proofreading Team at http://www.pgdp.net (This file was
produced from images generously made available by The
Internet Archive)









                     TWENTIETH CENTURY INVENTIONS

                              A Forecast

                                  BY
                       GEORGE SUTHERLAND, M.A.


                       LONGMANS, GREEN, AND CO.
                      39 PATERNOSTER ROW, LONDON
                          NEW YORK AND BOMBAY
                                 1901




                              PREFACE.


Twenty years ago the author started a career in technological
journalism by writing descriptions of what he regarded as the most
promising inventions which had been displayed in international
exhibitions then recently held. From that time until the present it
has been his constant duty and practice to take note of the advance of
inventive science as applied to industrial improvement--to watch it as
an organic growth, not only from a philosophical, but also from a
practical, point of view. The advance towards the actual adoption of
any great industrial invention is generally a more or less collective
movement; and, in the course of a practice such as that referred to,
the habit of watching the signs of progress has been naturally
acquired.

Moreover, it has always been necessary to take a comprehensive, rather
than a minute or detailed, view of the progress of the great
industrial army of nineteenth century civilisation towards certain
objectives. It is better, for some purposes of technological
journalism, to be attached to the staff than to march with any
individual company--for the war correspondent must ever place himself
in a position from which a bird's-eye view is possible. The personal
aspect of the campaign becomes merged in that which regards the army
as an organic unit.

It may, therefore, be claimed that, in some moderate degree, the
author is fitted by training and opportunities for undertaking the
necessarily difficult task of foretelling the trend of invention and
industrial improvement during the twentieth century. He must, of
course, expect to be wrong in a certain proportion of his
prognostications; but, like the meteorologists, he will be content if
in a fair percentage of his forecasts it should be admitted that he
has reasoned correctly according to the available data.

The questions to be answered in an inquiry as to the chances of
failure or success which lie before any invention or proposed
improvement are, first, whether it is really wanted; and, secondly,
whether the environment in the midst of which it must make its début
is favourable. These requirements generally depend upon matters which,
to a large extent, stand apart from the personal qualifications of any
individual inventor.

In the course of a search through the vast accumulations of the patent
specifications of various countries, the thought is almost
irresistibly forced upon the mind of the investigator that "there is
nothing new under the sun". No matter how far back he may push his
inquiry in attempting to unveil the true source of any important idea,
he will always find at some antecedent date the germ, either of the
same inventive conception, or of something which is hardly
distinguishable from it. The habit of research into the origin of
improved industrial method must therefore help to strengthen the
impression of the importance of gradual growth, and of general
tendencies, as being the prime factors in promoting social advancement
through the success of invention.

The same habit will also generally have the effect of rendering the
searcher more diffident in any claims which he may entertain as to
the originality of his own ideas. Inventive thought has been so
enormously stimulated during the past two or three generations, that
the public recognition of a want invariably sets thousands of minds
thinking about the possible methods of ministering to it.

Startling illustrations of this fact are continually cropping up in
the experiences of patent agents and others who are engaged in
technological work and its literature. The average inventor is almost
always inclined to imagine--when he finds another man working in
exactly the same groove as himself--that by some means his ideas have
leaked out, and have been pirated. But those who have studied
invention, as a social and industrial force, know that nothing is more
common than to find two or more inventors making entirely independent
progress in the same direction.

For example, while this book was in course of preparation the author
wrote out an account of an application of wireless telegraphy to the
purpose of keeping all the clocks within a given area correct to one
standard time. Within a few days there came to hand a copy of
_Engineering_ in which exactly the same suggestion was put forward,
and an announcement was made to the effect that Mr. Richard Kerr,
F.G.S., had been working independently on the same lines, the details
of his method of applying the Hertzian waves to the purpose being
practically the same as those sketched out by the author. This is only
one of several instances of coincidences in independent work which
have been noticed during the period while this volume was in course of
preparation.

It may, therefore, be readily understood that the author would hardly
like to undertake the task of attempting to discriminate between those
forecasts in the subsequent pages which are the results of his own
original suggestions, and those which have been derived from other
sources. Whatever is of value has in all probability been thought of,
or perhaps patented and otherwise publicly suggested, before. At any
rate, the great majority of the forecasts are based on actual records
of the trials of inventions which distinctly have a future lying
before them in the years of the twentieth century.

In declining to enter into questions relating to the original
authorship of the improvements or discoveries discussed, it should not
be supposed that any wish is implied to detract from the merits of
inventors and promoters of inventions, either individually or
collectively. Many of these are the heroes and statesmen of that great
nation which is gradually coming to be recognised as a true entity
under the name of Civilisation. Their life's work is to elevate
humanity, and if mankind paid more attention to them, and to what they
are thinking and doing, instead of setting so much store by the
veriest tittle-tattle of what is called political life, it would make
much faster progress.

Some of the industrial improvements referred to in the succeeding
pages are necessarily sketched in an indefinite manner. The outlines,
as it were, have been only roughed in; and no attempt has been made to
supply particulars, which in fact would be out of place in an essay
towards a comprehensive survey in so small a space. It is upon the
wise and skilful arrangement of details that sound and commercially
profitable patents are usually founded, rather than upon the broad
general principles of a proposed industrial advance or reform.

During the twentieth century this latter fact, already well recognised
by experts in what is known as industrial property, will doubtless
force itself more and more upon the attention of inventors. Every
specification will require to be drawn up with the very greatest care
in observing the truth taught by the fable of the boy and the jar of
nuts. So rapidly does the mass of bygone patent records accumulate,
that almost any kind of claim based upon very wide foundations will be
found to have trenched upon ground already in some degree taken up.

Probably there is hardly anything indicated in this work which is
not--in the strict sense of the rules laid down for examiners in those
countries which make search as to originality--common public property.
The labour involved in gathering the data for a forecast of the
inventions likely to produce important effects during the twentieth
century has been chiefly that of selecting from out of a vast mass of
heterogeneous ideas those which give promise of springing up amidst
favourable conditions and of growing to large proportions and bearing
valuable fruit. Such ideas, when planted in the soil of the collective
mind through the medium of official or other records, generally
require for their germination a longer time than that for which the
patent laws grant protection for industrial property. Many of them,
indeed, have formed the subjects of patents which, from one reason or
another, lapsed long before the expiration of the maximum terms.
Nature is ever prodigal of seeds and of "seed-thoughts" but
comparatively niggardly of places in which the young plant will find
exactly the kind of soil, air, rain, and sunshine which the young
plant needs.

If any one requires proof of this statement he will find ample
evidence in support of it in the tenth chapter of Smiles's work on
_Industrial Biography_, where facts and dates are adduced to show that
steam locomotion, reaping machines, balloons, gunpowder, macadamised
roads, coal gas, photography, anæsthesia, and even telegraphy are
inventions which, so far as concerns the germ idea on which their
success has been based, are of very much older origin than the world
generally supposes. The author, therefore, submits that he is
justified in referring inventions to the century in which they produce
successful results, not to that in which they may have been first
vaguely thought of. And in this view it is obvious that many of those
patents and suggestions which have been published in current
literature during the nineteenth century, but which, although pregnant
with mighty industrial influences, have not yet reached fruition, are
essentially inventions of the twentieth century. More than this, it is
extremely probable that the great majority of those ideas which will
move the industrial world during the next ensuing hundred years have
already been indicated, more or less clearly, by the inventive thought
of the nineteenth century.

                                                GEORGE SUTHERLAND.

    _December_, 1900.




                              CONTENTS.


                                                            PAGE
    CHAPTER I.
    INVENTIVE PROGRESS                                         1

    CHAPTER II.
    NATURAL POWER                                             22

    CHAPTER III.
    STORAGE OF POWER                                          53

    CHAPTER IV.
    ARTIFICIAL POWER                                          72

    CHAPTER V.
    ROAD AND RAIL                                             91

    CHAPTER VI.
    SHIPS                                                    122

    CHAPTER VII.
    AGRICULTURE                                              144

    CHAPTER VIII.
    MINING                                                   167

    CHAPTER IX.
    DOMESTIC                                                 195

    CHAPTER X.
    ELECTRIC MESSAGES, ETC.                                  216

    CHAPTER XI.
    WARFARE                                                  233

    CHAPTER XII.
    MUSIC                                                    249

    CHAPTER XIII.
    ART AND NEWS                                             264

    CHAPTER XIV.
    INVENTION AND COLLECTIVISM                               276




                              CHAPTER I.

                         INVENTIVE PROGRESS.


The year 1801, the first of the nineteenth century, was _annus
mirabilis_ in the industrial history of mankind. It was in that year
that the railway locomotive was invented by Richard Trevithick, who
had studied the steam engine under a friend and assistant of James
Watt. His patent, which was secured during the ensuing year, makes
distinct mention of the use of his locomotive driven by steam upon
tramways; and in 1803 he actually had an engine running on the
Pen-y-Darran mining tramway in Cornwall. From that small beginning has
grown a system of railway communication which has brought the farthest
inland regions of mighty continents within easy reach of the seaboard
and of the world's great markets; which has made social and friendly
intercourse possible in millions of homes which otherwise would have
been almost destitute of it; which has been the means of spreading a
knowledge of literature, science and religion over the face of the
civilised world; and which, at the present moment, constitutes the
outward and visible sign of the difference between Western
civilisation and that of the Asiatic, as seen in China.

In another corner of the globe, during the year 1801, Volta was
constructing his first apparatus demonstrating the material and
physical nature of those mysterious electric currents which his friend
Professor Galvani of Bologna, who died just two years earlier, had at
first ascribed to a physiological source. The researches of the
latter, it will be remembered, were begun in an observation of the way
in which the legs of a dead frog twitched under certain conditions.
The voltaic pile was the first electric battery, and, therefore, the
parent of the existing marvellous telegraphic and telephonic systems,
while less immediately it led to the development of the dynamo and its
work in electric lighting and traction. It brought into harmony much
fragmentary knowledge which had lain disjointed in the armoury of the
physicist since Dufay in France and Franklin in America had
investigated their theories of positive and negative frictional
electricities, and had connected them with the flash of lightning as
seen in Nature. Thus it became a fresh starting point both for
industry and for science.

At the Exposition of National Industry, held in Paris during the year
1801, a working model of the Jacquard loom was exhibited--the
prototype of those remarkable pieces of mechanism by which the most
elaborately figured designs are worked upon fabrics during the process
of weaving by means of sets of perforated cardboards. This was the
crowning achievement of the inventions relating to textile fabrics,
which had rendered the latter half of the eighteenth century so
noteworthy in an industrial sense. It brought artistic designs in
articles of common use within the reach of even poor people, and has
been the means of unconsciously improving the public taste, in matters
of applied art, more rapidly than could have been accomplished by an
army of trained artists. The riots in which the mob nearly drowned
Jacquard at Lyons for attempting to set up some of his looms were very
nearly a counterpart of those which had occurred in England in
connection with the introduction of spinning, weaving and knitting
machinery.

In Paris, during the first year of the nineteenth century, Robert
Fulton, an American, and friend of the United States representative in
France, was making trials on the Seine with his first steam-boat--a
little vessel imitated by him later on in the first successful
steamers which plied on the river Hudson, carrying passengers from New
York. At the same time, William Symongton launched the _Charlotte
Dundas_, the steam tug-boat which, on the Scottish canals, did the
first actually useful work in the conveyance of goods by steam power
on the water. These small experiments have initiated a movement in
maritime transport which is fully comparable to that brought about on
land by the invention of the railway locomotive.

Again, in 1801, Sir Humphry Davy gave his first lecture at the Royal
Institution in London, where he had just been installed as a
professor, and began that long series of investigations into the
chemistry of common things which, taken up by his successor Faraday,
gave to the United Kingdom the first start in some of those industries
depending upon a knowledge of organic chemistry and the use of certain
essential oils.

Public attention at the beginning of the nineteenth century, however,
was directed anywhere but towards these small commencements of mighty
forces which were to revolutionise the industrial world, and through
it also the social and political. If in those days Cornwall was ever
referred to, it was not by any means in connection with Trevithick and
his steam-engine which would run on rails, but by way of reference to
the relations of the Prince of Wales to the Duchy, and the proportion
of its revenues which belonged to him from birth.

Glancing over the pages of any history compiled in the early half of
the century, the eye will trace hardly the barest allusions to forces,
the discoveries in which were, in the year 1801, still in the
incipient stage. Canon Hughes, for instance, in his continuation of
the histories of Hume and Smollett, devoted some forty pages to the
record of that year. The space which he could spare from the demands
made upon his attention by the wars in Spain and Egypt, and the naval
conflict with France, was mainly occupied with such matters as the
election of the Rev. Horne Tooke for Old Sarum, and the burning
question as to whether that gentleman had not rendered himself
permanently ineligible for Parliamentary honours through taking Holy
Orders, and with a miscellaneous mass of topics relating to the merely
evanescent politics of the day.

The whole of the effects of invention and discovery in making history
during the first year of the century were dismissed by this writer
with a casual reference to the augmentation of the productive power of
the labouring population through the use of machinery, and a footnote
stating that "this was more particularly the case in the cotton
manufacture".

Time corrects the historical perspective of the past, but it does not
very materially alter the power of the historical vision to adjust
itself to an examination of the present day forces which are likely to
grow to importance in the making of future history. When we ask what
are the inventions and discoveries which are really destined to grow
from seeds of the nineteenth into trees of the twentieth century, we
are at once confronted with the same kind of difficulty which would
present itself to one who, standing in the midst of an ancient forest,
should be requested to indicate in what spots the wide-spreading
giants of the next generation of trees might be expected to grow. The
company promoter labels those inventions in which he is commercially
interested as the affairs which will grow to huge dimensions in the
future; while the man of scientific or mechanical bent is very apt to
predict a mighty future only for achievements which strike him as
being peculiarly brilliant.

Patent experts, on the other hand, when asked by their clients to
state candidly what class of inventions may be relied upon to bring
the most certain returns, generally reply that "big money usually
comes from small patents". In other words, an invention embodying some
comparatively trivial, but yet really serviceable, improvement on a
very widely used type of machine; or a little bit of apparatus which
in some small degree facilitates some well known process; or a
fashionable toy or puzzle likely to have a good run for a season or
two, and then a moderate sale for a few years longer; these are the
things to be recommended to an inventor whose main object is to make
money. Thus the most qualified experts in patent law and practice do
not fail to disclose this fact to those who seek their professional
advice in a money-making spirit, as the great majority of inventors
do.

The full term of fourteen years in the United Kingdom, or seventeen in
the United States, may be a ridiculously long period for which to
grant a monopoly to the inventor of some ephemeral toy, although
absolutely inadequate to secure the just reward for one who labours
for many years to perfect an epoch-making invention, and then to
introduce it to the public in the face of all the opposition from
vested interests which such inventions almost invariably meet.

Thus the fact that a man has made money out of one class of patents
may not be any safe guide at all to arriving at a due estimate of his
ideas on industrial improvements of greater "pith and moment," but, on
the contrary, it is generally exactly the reverse. The law offers an
immense premium for such inventions as are readily introduced, and the
inventor who has made it his business to take advantage of this fact
is usually one of the last men from whom to get a trustworthy opinion
on patents of a different class.

Of the patents taken out during the latter portion of the nineteenth
century, many undoubtedly contain the germs of great ideas, and,
nevertheless, have excited comparatively little attention from
business men or from the general public. It was so in the latter part
of the eighteenth century, and history is only repeating itself when
the seeds of twentieth century industrial movements are permitted to
germinate unseen.

For all practical purposes each invention must be referred to the age
in which it actually does useful work in the service of mankind. Thus,
Hero of Alexandria, in the third century B.C., devised a water
fountain worked by the expansive power of steam. From time to time
during the succeeding twenty centuries similar pieces of apparatus
excited the curiosity of the inquisitive and the interest of the
learned. The clever and eccentric Marquis of Worcester, in his little
book published in 1663, _A Century of the Names and Scantlings of
Inventions_, generally known as the _Century of Inventions_, gave an
account of one application of the power of steam to lift water which
he had worked out, probably on a scale large enough to have become of
practical service. Thomas Savery and Denis Papin, both of them men of
high attainments and great ingenuity, made important improvements
before the end of the seventeenth century.

Yet, if we refer to the question as to the proper age to which the
steam-engine as a useful invention is to be assigned, we shall
unhesitatingly speak of it as an eighteenth century invention, and
this notwithstanding the fact that Savery's patent for the first
pumping engine which came into practical use was dated 1698. The real
introduction of steam as a factor in man's daily work was effected
later on, partly by Savery himself and partly by Newcomen, and above
all by James Watt. The expiration of Watt's vital patent occurred in
1800, and he himself then retired from the active supervision of his
engineering business, having virtually finished his great life's work
on the last year of the century which he had marked for all time by
the efforts of his genius.

Similarly we may confidently characterise the locomotive engine as an
invention belonging to the first half of the nineteenth century,
although tramways on the one hand, and steam-engines on the other
hand, were ready for the application of steam transport, and the only
work that remained to be accomplished in the half century indicated
was the bringing of the two things together. The dynamo, as a factor
in human life--or, in other words, the electric current as a form of
energy producing power and light--is an invention of the second half
of the nineteenth century, although the main principles upon which it
was built were worked out prior to the year 1851.

It will be seen, in the course of the subsequent pages, that portable
electric power has as yet won its way only into very up-to-date
workshops and mines, and that the means by which it will be applied to
numerous useful purposes in the field, the road, and the house will be
distinctly inventions of the twentieth century. Similarly the
steam-engine has not really been placed upon the ordinary road,
although efforts have been made for more than a century to put it
there, the conception of a road locomotive being, in fact, an earlier
one than that of an engine running on rails. Steam automobiles and
traction engines are still confined to special purposes, the natures
of which prove that certain elements of adaptability are still lacking
in order to render them universally useful as are the locomotive and
the steam-ship.

In nearly every other important line of human needs and desires it
will be found that merely tentative efforts have been made by
ingenious minds resulting in inventions of greater or less promise.
Many of the finest conceptions which have necessarily been set down as
failures have missed fulfilling their intended missions, not so much
by reason of inherent weakness, as through the want of accessory
circumstances to assist them. As in biology, so in industrial progress
the definition of fitness appended to the law of the survival of the
fittest must have reference to the environment.

A foolish law or public prejudice results in the temporary failure of
a great invention, and the inventor's patent succumbs to the
inexorable operation of the struggle for existence. Yet, fortunately
for mankind, if not for the individual inventor, an idea does not
suffer extinction as the penalty for non-success in the struggle. "The
beginning of creation," says Carlyle, "is light," and the kind of
light which inventors throw upon the dark problems involving man's
industrial progress is providentially indestructible.

Twentieth century inventions--as the term is used in this book--are,
therefore, those which are destined to fulfil their missions during
the ensuing hundred years. They are those whose light will not only
exist in hidden places, but will also shine abroad to help and to
bless mankind. Or, if we may revert to the former figure, they are
those which have not only been planted in the seed and have germinated
in the leaf, but which have grown to goodly proportions, so that none
may dare to assert that they have been planted for nought. A man's age
is the age in which he does his work rather than that in which he
struggles to years of maturity. Moore and Byron were poets of the
nineteenth century, although the one had attained to manhood and the
other had grown from poverty to inherit a peerage before the new
century dawned.

The prophetic rôle--although proverbially an unsafe one--is
nevertheless one which every business man must play almost every day
of his life. The merchant, the manufacturer, the publisher, the
director, the manager, and even the artist, must perforce stake some
portion of his success in life upon the chance of his forecast as to
the success of a particular speculation, article of manufacture, or
artistic conception, and its prospects of proving as attractive or
remunerative as he has expected it to be. The successful business man
no doubt makes his plans, as far as may be practicable, upon the
system indicated by the humorist, who advises people never to prophesy
unless they happen to know, but the nature of his knowledge is almost
always to some extent removed from certainty. He may spend much time
in laborious searching; make many inquiries from persons whom he
believes to be competent to advise him; diligently study the
conditions upon which the problem before him depends--in short, he may
take every reasonable precaution against the chances of failure, yet,
in spite of all, he must necessarily incur risks. And so it is with
regard to the task of forecasting the trend of industrial improvement.
All who are called upon to lay their plans for a number of years
beforehand must necessarily be deeply interested in the problems
relating to the various directions which the course of that
improvement may possibly take. Meanwhile their estimates of the
future, although based upon an intimate knowledge of the past and
aided by naturally clear powers of insight, must be hypothetical and
conditional. Unfortunately for the vast majority of manufacturing
experts, the thoroughness with which they have mastered the details of
one particular branch of industry too often blinds them to the chances
of change arising from localities beyond their own restricted fields
of vision.

The merriment occasioned by the first proposals for affixing pneumatic
tyres to bicycles may be cited as a striking instance of the lack of
forecasting insight displayed by very many of those who are best
entitled to pronounce opinions on the minutiae of their particular
avocations. In almost every "bike" shop and factory throughout the
United Kingdom and America, the suggestion of putting an air-filled
hosepipe around each wheel of the machine to act as a tyre was
received with shouts of ridicule!

Railway men, who understood the wonderful elasticity imparted by air
to pieces of mechanism, such as the pneumatic brake, were not by any
means so much inclined to laughter; but naturally, for the most part,
they deferred to the rule which enjoins every man to stick to his
trade. The rule in question--when applied to the task of estimating
the worth of inventions claiming to produce revolutionary effects in
any industry--is necessarily, in the majority of cases, more or less
irrelevant, because such an invention should be regarded not so much
as a proposed _innovation_ in an old trade as the _creation_ of a new
one.

George Stephenson's ideas on the transport of passengers and goods
were almost unanimously condemned by the experts of his day who were
engaged in that line of business. On points relating to wheels of
waggons and the harness of horses, the opinions of these men were
probably worth something; but in relation to steam locomotives,
carriages and trucks running upon rails, their judgment was not merely
worthless, but a good deal worse; it was indeed actually misleading,
because based on a pretence of knowledge of a trade which was to be
called into existence to compete with their own. "Great is Diana of
the Ephesians" said the artificers of old; and on the strength of
their expert knowledge in the making of idols they set themselves up
as judges of systems of theology and morality. The argument, although
based on self-interest subjectively, was nevertheless intended to
carry weight even among persons who wished to judge the questions in
dispute according to their merits, and most of the latter were only
too ready to accept the implied dictum that men who work about a
temple must be experts in theology! The principles upon which Royal
Commissions and Select Committees are sometimes appointed and
entrusted with the onerous duty of deciding upon far-reaching
industrial problems, affecting the progress of trade and manufactures
in the present day, involve exactly the same kind of fallacy. Men are
selected to pronounce judgment upon the proposals of their rivals in
trade, and narrow-minded specialists to give their opinions upon
projects which essentially belong to the border lands between two or
more branches of industry, and cannot be understood by persons not
possessing a knowledge of both.

Yet the world's work goes on apace; and as capital is accumulated and
seeks to find new outlets the multiplication of industrial projects
must continue in spite of every discouragement. This process will go
on at a rate even faster than that which was exhibited at the
beginning of the nineteenth century; but in watching the course of
advancement, the world must take count of ideas rather than of the
names of those who may have claims to rank as the originators of
ideas. While for purposes of convenience, history labels certain great
inventive movements, each with the name of one pre-eminent individual
who has contributed largely to its success, nothing like a due
appraisement of the services rendered by other men is ever attempted.
It is not even as if the commanding general should by public
acclamation receive all the applause for a successful campaign to the
exclusion of his lieutenants. The pioneers in each great department of
invention have generally acted as forerunners of the men whose names
have become the most famous. They have borne much of the heat and
burden of the day, while their successors have reaped the fruits of
triumph. Mr. Herbert Spencer's strong protest against the part
assigned by some writers in the mental and industrial evolution of the
human race to the influence of great men is certainly fully justified,
if the attribute of greatness is to be ascribed only to those whose
names figure in current histories. The parts performed by others,
whose fate it may have been to have fallen into comparatively
unfavourable environments, may have entitled them even more eminently
to the acclamation of greatness.

The world in such a matter asks, reasonably enough under the
circumstances, Shall we omit to honour any of the great men who have
played important parts in an industrial movement, assigning as our
motive the difficulty of enumerating so many names? For the
encouragement of those to whom the ambition for fame acts as a great
stimulus to self-devotion in the interests of human progress, it is
unavoidable that some men should be singled out and made heroes, while
the much more numerous class of those who have also done great work,
but who have not been quite so successful, must pass out of the ken of
all, excepting the few who possess an expert knowledge of the various
subjects which they have taken in hand.

Still the distortion to which history has been subjected through its
biographical mode of treatment must always be reckoned with as a
factor of possible error by any one attempting to read the riddle of
the past, and it may offer a still more dangerous snare to one who
tries to deduce the future course of events from the evidences of the
past, and the promises which they hold out. People are naturally prone
to take it for granted that the world's progress during the first part
of the twentieth century depends upon the future work of those
inventors and industrial promoters whose names have become most
famous during the latter half of the nineteenth. But this personal
treatment of the subject will be found to be in the last degree
unsatisfactory, when judged in the light both of past experience and
of some of the utterances of those eminent inventors who have tried to
forecast the future in their own particular lines of research.

If, therefore, we look at the whole subject from the entirely
impersonal point of view, and face the task of forecasting the
progress of industry during the twentieth century, in this aspect we
shall find that we have entered upon a chapter in the evolution of the
human race--dealing, in fact, with a branch of anthropology. We see
certain industrial and inventive forces at work, producing certain
initial effects, but plainly, as yet, falling immeasurably short of an
entire fulfilment of their possibilities; setting to work a multitude
of busy brains, planning and arranging, and gradually preparing the
minds of the more apathetic portion of humanity for the reception of
new ideas and the adoption of improved methods of life and of work.
Whither is it all tending? Will the twentieth century bring about as
great a change upon the earth--man's habitat--as the nineteenth did?
Or have the possibilities of really great and effective industrial
revolutions been practically exhausted? The belief impressed upon the
Author's mind, by facts and considerations evoked during the
collection of materials for this book, is that the march of industrial
progress is only just beginning, and that the twentieth century will
witness a far greater development than the nineteenth has seen.

The great majority of mankind still require to be released from the
drudgery of irksome, physical exertion, which, when power has been
cheapened, will be seen to be to a very large extent avoidable.
Pleasurable exercise will be substituted for the monotonous, manual
labour which, while it continues, generally precludes the possibility
of mental improvement. Hygienic science will insist more strenuously
than ever upon the great truth that, in order to be really serviceable
in promoting the health of mind and body, physical exertion must be in
some degree exhilarating, and the bad old practice of "all work and no
play," which was based upon the assumption that a boy can get as much
good out of chopping wood for an hour as out of a bicycle ride or a
game of cricket, will be relegated to the limbo of exploded fallacies.

The race, as a whole, will be athletic in the same sense in which
cultured ladies and gentlemen are at present. It will, a century
hence, offer a still more striking contrast to the existing state of
the Chinese, who bandage their women's feet in order to show that they
are high born and never needed to walk or to exert themselves!--the
assumption being that no one would ever move a muscle unless under
fear of the lash of poverty or of actual hunger. The farther Western
civilisation travels from that effete Eastern ideal, the greater will
be the hope for human progress in physical, mental and moral
well-being.




                              CHAPTER II.

                            NATURAL POWER.


"Nature," remarked James Watt when he set to work inventing his
improved steam-engine, "has always a weak side if we can only find it
out." Many invaluable secrets have been successfully explored through
the discovery of Nature's "weak side" since that momentous era in the
industrial history of the world; and the nineteenth century, as Watt
clearly foresaw, has been emphatically the age of steam power. In the
condenser, the high pressure cylinder and the automatic cut-off, which
utilises the expansive power of steam vapour, mankind now possesses
the means of taming a monster whose capacities were almost entirely
unknown to the ancients, and of bringing it into ready and willing
service for the accomplishment of useful work. Vaguely and loosely it
is often asserted that the age of steam is now giving place to that of
electricity; but these two cannot yet be logically placed in
opposition to one another. No method has yet been discovered whereby
the heat of a furnace can be directly converted into an electric
current. The steam-engine or, as Watt and his predecessors called it,
the "fire-engine" is _par excellence_ the world's prime motor; and by
far the greater proportion of the electrical energy that is generated
to-day owes its existence primarily to the steam-engine and to other
forms of reciprocating machinery designed to utilise the expansive
power of vapours or gases acting in a similar manner to steam.

The industrial revolutions of the coming century will, without doubt,
be brought about very largely through the utilisation of Nature's
waste energy in the service of mankind. Waterfalls, after being very
largely neglected for two or three generations, are now commanding
attention as valuable and highly profitable sources of power. This is
only to be regarded as forming the small beginning of a movement
which, in the coming century, will "acquire strength by going," and
which most probably will, in less than a hundred years, have produced
changes in the industrial world comparable to those brought about by
the invention of the steam-engine.

Lord Kelvin, in the year 1881, briefly, but very significantly,
classified the sources of power available to man under the five
primary headings of tides, food, fuel, wind, and rain. Food is the
generator of animal energy, fuel that of the power obtained from steam
and other mechanical expansive engines; rain, as it falls on the
hill-tops and descends in long lines of natural force to the sea
coasts, furnishes power to the water-wheel; while wind may be utilised
to generate mechanical energy through the agency of windmills and
other contrivances. The tides as a source of useful power have hardly
yet begun to make their influence felt, and indeed the possibility of
largely using them is still a matter of doubt. The relative advantages
of reclaiming a given area of soil for purposes of cultivation, and of
converting the same land into a tidal basin in order to generate power
through the inward and outward flow of the sea-water, were contrasted
by Lord Kelvin in the statement of a problem as follows: Which is the
more valuable--an agricultural area of forty acres or an available
source of energy equal to one hundred horse-power? The data for the
solution of such a question are obviously not at hand, unless the
quality of the land, its relative nearness to the position at which
power might be required, and several other factors in its economic
application have been supplied. Still, the fact remains that very
large quantities of the coastal land and a considerable quantity of
expensive work would be needed for the generation, by means of the
tides, of any really material quantity of power.

It is strange that, while so much has been written and spoken about
the possibility of turning the energy of the tides to account for
power in the service of man, comparatively little attention has been
paid to the problem of similarly utilising the wave-power, which goes
to waste in such inconceivably huge quantities. Where the tidal force
elevates and depresses the sea-water on a shore, through a vertical
distance of say eight feet, about once in twelve hours, the waves of
the ocean will perform the same work during moderate weather once in
every twelve or fifteen seconds. It is true that the moon in its
attraction of the sea-water produces a vastly greater sum total of
effect than the wind does in raising the surface-waves, but reckoning
only that part of the ocean energy which might conceivably be made
available for service it is safe to calculate that the waves offer
between two and three thousand times as much opportunity for the
capture of natural power and its application to useful work as the
tides could ever present. In no other form is the energy of the wind
brought forward in so small a compass or in so concrete a form. A
steam-ship of 10,000 tons gross weight which rises and falls ten times
per minute through an average height of 3·3 feet is thereby subjected
to an influence equal to 22,400 horse-power. In this estimate the unit
of the horse-power which has been adopted is Watt's arbitrary standard
of "33,000 foot pounds per minute". The work done in raising the
vessel referred to is equal to ten horse-power multiplied by the
number of pounds in a ton, or, in other words, 22,400 horse-power, as
stated.

Wind-power, again, has been to a large extent neglected since the
advent of the steam-engine. The mightiest work carried out in any
European country in the early part of the present century was that
which the Dutch people most efficiently performed in the draining of
their reclaimed land by means of scores of windmills erected along
their seaboard. Even to the present day there are no examples of the
direct employment of the power of the wind which can be placed in
comparison with those still to be found on the coasts of Holland. But,
unfortunately for the last generation of windmill builders, the
intermittent character of the power to which they had to trust
completely condemned it when placed in competition with the handy and
always convenient steam-engine. The wind bloweth "where it listeth,"
but only at such times and seasons as it listeth, and its vagaries do
not suit an employer whose wages list is mounting up whether he has
his men fully occupied or not. The storage of power was the great
thing needful to enable the windmill to hold its own. The electrical
storage battery, compressed air, and other agencies which will be
referred to later on, have now supplied this want of the windmill
builder, but in the meantime his trade has been to a large extent
destroyed. For its revival there is no doubt that, as Lord Kelvin
remarked in the address already quoted, "the little thing wanted to
let the thing be done is cheap windmills."

This, however, leads to another part of the problem. The costliness of
the best modern patterns of windmill as now so extensively used,
particularly in America, is mainly due to the elaborate, and, on the
whole, successful attempts at minimising the objection of the
intermittent nature of the source of power. To put the matter in
another way, it may be said that lightness, and sensitiveness to the
slightest breeze, have had to be conjoined with an eminent degree of
safety in the severest gale, so that the most complicated
self-regulating mechanisms have been rendered absolutely imperative.
Once the principle of storage is applied, the whole of the conditions
in this respect are revolutionised. There is no need to attempt the
construction of wind-motors that shall run lightly in a soft zephyr of
only five or six miles an hour, and stability is the main desideratum
to be looked to.

The fixed windmill, which requires no swivel mechanism and no vane to
keep it up to the wind, is the cheapest and may be made the most
substantial of all the forms of wind-motor. In its rudimentary shape
this very elementary windmill resembles a four-bladed screw steam-ship
propeller. The wheel may be constructed by simply erecting a high
windlass with arms bolted to the barrel at each end, making the shape
of a rectangular cross. But those at one end are fixed in such
positions that when viewed from the side they bisect the angles made
by those at the other side. Sails of canvas or galvanised iron are
then fastened to the arms, the position of which is such that the
necessary obliquity to the line of the barrel is secured at once.

Looking at this elementary and at one time very popular form of
windmill, and asking ourselves what adaptation its general principle
is susceptible of in order that it may be usefully employed in
conjunction with a storage battery, we find, at the outset, that,
inasmuch as the electric generator requires a high speed, there is
every inducement to greatly lengthen the barrel and at the same time
to make the arms of the sails shorter, because short sails give in the
windmill the high rate of speed required.

We are confronted, in fact, with the same kind of problem which met
the constructors of turbine steam-engines designed for electric
lighting. The object was to get an initial speed which would be so
great as to admit of the coupling of the dynamo to the revolving shaft
of the turbine steam-motor, without the employment of too much
reducing gear. In the case of the wind-motor the eighteenth century
miller was compelled to make the arms of his mill of gigantic length,
so that, while the centre of the wind pressure on each arm was
travelling at somewhere near to the rate of the wind, the axis would
not be running too fast and the mill stones would never be grinding so
rapidly as to "set the _tems_--or the lighter parts of the corn--on
fire."

The dynamo for the generation of the electric current demands exactly
the opposite class of conditions. We may therefore surmise that the
windmill of the future, as constructed for the purposes of storing
power, will have a long barrel upon which will be set numerous very
short blades or sails. Reducing this again to its most convenient
form, it is plain that a spiral of sheet-metal wound round the barrel
will offer the most convenient type of structure for stability and
cheapness combined. At the end of this long barrel will be fixed the
dynamo, the armature of which is virtually a part of the barrel
itself, while the magnets are placed in convenient positions on the
supporting uprights. From the generating dynamo the current is
conveyed directly to the storage batteries, and these alone work the
electric motor, which, if desired, keeps continually in motion,
pumping, grinding, or driving any suitable class of machinery.

It is rather surprising to find how relatively small is the advantage
possessed by the vane-windmill over the fixed type in the matter of
continuity of working. During about two years the Author conducted a
series of experiments with the object of determining this point, the
fixed windmill being applied to work which rendered it a matter of
indifference in which way the wheel ran. With the prevailing winds
from the west it ran in one direction, and with those of next degree
of frequency, namely from the east, it turned in the reverse
direction. The mill, however, was effective although the breeze might
veer several points from either of the locations mentioned. It was
found that there were rather less than one-fourth of the points of the
compass, the winds from which would bring the wheel to a standstill or
cause it to swing ineffectively, but as these were the directions in
which the wind least frequently blew it might safely be reckoned that
not one-eighth of the possible working hours of a swivel-windmill were
really lost in the fixed machine.

With the type adapted to the working of a dynamo as already described,
it will, in most cases, be convenient to construct two spirals on
uprights set in three holes in the ground, forming lines at right
angles to each other, but both engaging, by suitable gearing, with the
electric current generator situated at the angle. This will be found
cheaper than to go to the expense of constructing the mill on a swivel
so that it may follow the direction of the wind. At the same time it
should be noticed that the adoption of the high speed wind-wheel,
consisting of some kind of spiral on a very long axis, may be made
effective for improving even the swivel windmill itself, so as to
adapt it for electric generation and conservation of power through the
medium of the storage battery. Supposing that a number of small
oblique sails be set upon an axis lying in the direction of the wind,
the popular conception of the result of such an arrangement is that
the foremost sails would render those behind it almost, if not
entirely, useless.

The analogy followed in reaching this conclusion is that of the sails
of a ship, but, as applied to wind-motors, it is quite misleading,
because not more than one-third or one-fourth of the energy of the
wind is expended upon the oblique sails of an ordinary wind-wheel.
Moreover, in the case of a number of such wheels set on a long axis,
one behind the other as described, the space within which the shelter
of the front sail is operative to keep the wind from driving the next
one is exceedingly minute.

The elasticity of the air and its frictional inertia when running in
the form of wind cause the current to proceed on its course after a
very slight check, which in point of time is momentary and in its
effects almost infinitesimal. This being the case, and the principal
expense attendant upon the construction of ordinary wind-engines being
due to the need for providing a large diameter of wind-wheel, with all
the attendant complications required to secure such a wheel from
risk, it is obvious that as soon as the long axis and the very short
sail, or the metallic spiral, have been generally introduced as
adjuncts to the dynamo storage battery, an era of cheaper wind-motors
will have been entered upon,--in fact, the "little want" of which Lord
Kelvin spoke in 1881 will have been supplied. The high speed which the
dynamo requires, and the more rapid rate at which windmills
constructed on this very economical principle must necessarily run,
both mark the two classes of apparatus as being eminently suited for
mutual assistance in future usefulness.

The anemometer of the "Robinson" type, having four little
hemispherical cups revolving horizontally, furnishes the first hint of
another principle of construction adapted to the generation of
electricity. Some years ago a professor in one of the Scottish
Universities set up a windmill which was simply an amplified
anemometer, and connected it with several of Faure's storage batteries
for the purpose of furnishing the electric light to his residence. His
report regarding his experience with this arrangement showed that the
results of the system were quite satisfactory.

In this particular type of natural motor the wind-wheel, of course, is
permanently set to run no matter from what direction the wind may be
blowing. Tests instituted with the object of determining the pressure
which the wind exerts on the cup of a "Robinson" anemometer have shown
that when the breeze blows into the concave side of the cup, its
effect is rather more than three times as strong as when it blows
against the convex side. At any given time the principal part of the
work done by a windmill constructed on this principle is being carried
out by one cup which has its concave side presented to the wind,
while, opposite to it, there is another cup travelling in the opposite
direction to that of the wind but having its convex side opposed.

The facts that practically only one sail of the mill is operative at
any given time, and that even the work which is done by this must be
diminished by nearly one-third owing to the opposing "pull" of the cup
at the opposite side, no doubt must detract from the merits of such a
wind-motor, judged simply on the basis of actual area of sail
employed. But when the matter of cost alone is taken as the standard,
the advantages are much more evenly balanced than they might at first
sight seem to be.

The cup-shaped sail may be greatly improved upon for power-generating
purposes by adopting a sail having a section not semicircular but
triangular in shape, and by extending its length in the vertical
direction to a very considerable extent. Practically this cheap and
efficient wind-motor then becomes a square or hexagonal upright axis
of fairly large section, to each side of which is secured a board or a
rigid sheet-metal sail projecting beyond the corners. The side of the
axis and the projecting portion of the sail then together form the
triangular section required.

For the sake of safety in time of storm, an opening may be left at the
apex of the angle which is closed by a door kept shut through the
tension of a spring. When the wind rises to such a speed as to
overbalance the force of the spring each door opens and lets the blast
pass through. One collateral advantage of this type of windmill is
that it may be made to act virtually as its own stand, the only
necessity in its erection being that it should have a collar fitting
round the topmost bearing, which collar is fastened by four strong
steel ropes to stakes securely set in the ground. The dynamo is then
placed at the lower bearing and protected from the weather by a metal
shield through which the shaft of the axis passes.

For pumping, and for other simple purposes apart from the use of
the dynamo, a ready application of this form of wind-engine with
a minimum of intricacy or expense may be worked out by setting the
lower bearing in a round tank of water kept in circular motion by
a set of small paddles working horizontally. Into the water a
vertically-working paddle-wheel dips, carrying on its shaft a crank
which directly drives the pump. This simple wind-motor is particularly
safe in a storm, because on attaining a high speed it merely "smashes"
the water in the tank.

Solar heat is one of the principal sources of the energy to be derived
from the wind. Several very determined and ingenious attempts at the
utilisation of the heat of sunshine for the driving of a motor have
been made during the past century. As a solution of a mechanical and
physical puzzle, the arrangement of a large reflector, with a small
steam-boiler at the focus of the heat rays thrown by it, is full of
interest. Yet, when a man like the late John Ericsson, who did so much
to improve the caloric engine, and the steam-ship as applied to
war-like purposes, meets with failure in the attempt to carry such an
idea to a commercially successful issue, there is at least _prima
facie_ evidence of some obstacle which places the proposed machine at
a disadvantage in competition with its rivals.

The solar engine, if generally introduced, would be found more
intermittent in its action than the windmill--excepting perhaps in a
very few localities where there is a cloudless sky throughout the
year. The windmill gathers up the power generated by the expansion of
the air in passing over long stretches of heated ground, while a solar
engine cannot command more of the sun's heat than that which falls
upon the reflector or condenser of the engine itself. The latter
machine may possibly have a place assigned to it in the industrial
economy of the future, but the sum total of the power which it will
furnish must always be an insignificant fraction.

The wave-power machine, when allied to electric transmission, will,
without doubt, supply in a cheap and convenient form a material
proportion of the energy required during the twentieth century for
industrial purposes. Easy and effective transmission is a _sine quâ
non_ in this case, just as it is in the utilisation of waterfalls
situated far from the busy mart and factory. Hardly any natural source
of power presents so near an approach to constancy as the ocean
billows. Shakespeare takes as his emblem of perpetual motion the
dancing "waves o' th' sea".

But the ocean coasts--where alone natural wave-power is constant--are
exactly the localities at which, as a rule, it is the least
practicable to build up a manufacturing trade. Commerce needs smooth
water for the havens offered to its ships, and inasmuch as this
requirement is vastly more imperative during the early stages of
civilisation than cheap power, the drift of manufacturing centres has
been all towards the calm harbours and away from the ocean coasts. But
electrical transmission in this connection abolishes space, and can
bring to the service of man the power of the thundering wave just as
it can that of the roaring torrent or waterfall.

The simplest form of wave-motor may be suggested by the force exerted
by a ferry boat or dinghy tied up to a pier. The pull exerted by the
rope is equal to the inertia of the boat as it falls into the trough
of each wave successively, and the amount of strain involved in rough
weather may be estimated from the thickness of the rope that is
generally found necessary for the security of even very small craft
indeed. A similar suggestion is conveyed by the need for elaborate
"fenders" to break the force of the shock when a barge is lying
alongside of a steamer, or when any other vessel is ranging along a
pier or jetty.

A buoy of large size, moored in position at a convenient distance
from a rock-bound ocean coast, will supply the first idea of a
wave-motor on this primary principle as adapted for the generation of
power. On the cliff a high derrick is erected. Over a pulley or wheel
on the top of this there is passed a wire-rope cable fastened on the
seaward side to the buoy, and on the landward side to the machinery in
the engine-house. The whole arrangement in fact is very similar in
appearance to the "poppet-head" and surface buildings that may be seen
at any well-equipped mine. The difference in principle, of course, is
that while on a mine the engine-house is supplying power to the other
side of the derrick, the relations are reversed in the wave-motor, the
energy being passed from the sea across into the engine-house. The
reciprocating, or backward and forward, movement imparted to the cable
by the rising and falling of the buoy now requires to be converted
into a force exerted in one direction. In the steam-engine and in
other machines of similar type, the problem is simplified by the
uniform length of the stroke made by the piston, so that devices such
as the crank and eccentric circular discs are readily applicable to
the securing of a rotatory motion for a fly-wheel from a reciprocating
motion in the cylinders. In the application of wave-power provision
must be made for the utilisation of the force derived from movements
of _differing lengths_, as well as of _differing characters_, in the
force of impact. Every movement of the buoy which imparts motion to
the pulley on top of the derrick must be converted into an additional
impetus to a fly-wheel always running in the same direction.

The spur-wheel and ratchet, as at present largely used in machinery,
offer a rough and ready means of solving this problem, but two very
important improvements must be effected before full advantage can be
taken of the principle involved. In the first place it is obvious that
if a ratchet runs freely in one direction and only catches on the
tooth of the spur-wheel when it is drawn in the other, the power
developed and used is concentrated on one stroke, when it might, with
greater advantage, be divided between the two; and in the second place
the shock occasioned by the striking of the ratchet against the tooth
when it just misses catching one of the teeth and is then forced along
the whole length of the tooth gathering energy as it goes, must add
greatly to the wear and tear of the machinery and to the unevenness of
the running.

Taking the first of these difficulties into consideration it is
obvious that by means of a counterbalancing weight, about equal to
half that of the buoy, it is possible to cause the wave-power to
operate two ratchets, one doing work when the pull is to landwards and
the other when it is to seawards. Each, however, must be set to catch
the teeth of its own separate spur-wheel; and, inasmuch as the
direction of the motion in one case is different from what it is in
the other, it is necessary that, by means of an intervening toothed
wheel, the motion of one of these should be reversed before it is
communicated to the fly-wheel. The latter is thus driven always in the
same direction, both by the inward and by the outward stroke or pull
of the cable from the buoy.

Perhaps the most convenient development of the system is that in which
the spur-wheel is driven by two vertically pendant toothed bands,
resembling saws, and of sufficient length to provide for the greatest
possible amplitude of movement that could be imparted to them by the
motion of the buoy. The teeth are set to engage in those of the
spur-wheel, one band on each side, so that the effective stroke in one
case is downward, while in the other it is upward. These toothed bands
are drawn together at their lower ends by a spring, and they are also
kept under downward tension by weights or a powerful spring beneath.
The effect of this is that when both are drawn up and down the
spur-wheel goes round with a continuous motion, because at every
stroke the teeth of one band engage in the wheel and control it, while
those of the reversed one (at the other side) slip quite freely.

The shock occasioned by the blow of the ratchet on the spur-wheel, or
of one tooth upon another, may be reduced almost to vanishing point by
multiplying the number of ratchets or toothed bands, and placing the
effective ends, which engage in the teeth of the wheel successively,
one very slightly in advance of the other. In this way the machine is
so arranged that, no matter at what point the stroke imparted by the
movement of the buoy may be arrested, there is always one or other of
the ratchets or of the teeth which will fall into engagement with the
tooth of the spur-wheel, very close to its effective face, and thus
the momentum acquired by the one part before it impinges upon the
other becomes comparatively small.

The limit to which it may be practicable to multiply ratchets or
toothed bands will, of course, depend upon the thickness of the
spur-wheel, and when this latter has been greatly enlarged, with the
object of providing for this feature, it becomes virtually a steel
drum having bevelled steps accurately cut longitudinally upon its
periphery.

The masts of a ship tend to assume a position at right angles to the
water-line. When the waves catch the vessel on the beam the greatest
degree of pendulous swing is brought about in a series of waves so
timed, and of such a length, that the duration of the swing coincides
with the period required for one wave to succeed another. The
increasing slope of the ship's decks, due to the inertia of this
continuous rhythmical motion, often amounts to far more than the angle
made by the declivity of the wave as compared with the sea level; and
it is, of course, a source of serious danger in the eyes of the
mariner.

But, for the purposes of the mechanician who desires to secure power
from the waves, the problem is not how to avoid a pendulous motion but
how to increase it. For each locality in which any large wave-power
plant of machinery is to be installed, it will therefore be advisable
to study the characteristic length of the wave, which, as observation
has proved, is shorter in confined seas than in those fully open to
the ocean. It is advisable then to make the beam width of the buoy,
no matter how it may be turned, of such a length that when one side is
well in the trough of a wave the other must be not far from the crest.

Practically the best design for such a floating power-generator will
be one in which four buoys are placed, each of them at the end of one
arm of a cross which has been braced up very firmly. From the angle of
intersection projects a vertical mast, also firmly held by stays or
guys. The whole must be anchored to the bottom of the sea by
attachment to a large cemented block or other heavy weight having a
ring let into it, from which is attached a chain of a few links
connecting with an upright beam. It is the continuation of the latter
above sea-level which forms the mast. On this beam the framework of
the buoy must be free to move up and down.

At first sight it might seem as if this arrangement rendered nugatory
the attempt to take advantage of the rise and fall of the buoy; but it
is not so when the relations of the four buoys to one another are
considered. Although the frame is free to move up and down upon the
uprising shaft, still its inclination to the vertical is determined by
the direction of the line drawn from a buoy in the trough of a wave to
one on the crest. In order to facilitate the free movement, and to
render the rocking effect more accurate and free from vibration, sets
of wheels running on rails fixed to the beam are of considerable
advantage.

The rise and fall of the tides render necessary the adoption of some
such compensating device as that which has been indicated. Of course
it would be possible to provide for utilising the force generated by a
buoy simply moored direct to a ring at the bottom by means of a common
chain cable; but this latter would require to be of a length
sufficient to provide for the highest possible wave on the top of the
highest tide. Then, again, the loose chain at low tide would permit
the buoy to drift abroad within a very considerable area of sea
surface, and in order to take advantage of the rise and fall on each
wave it would be essential to provide at the derrick on the shore end
of the wave-power plant very long toothed bands or equivalent devices
on a similarly enlarged scale.

By providing three or four chains and moorings, meeting in a centre at
the buoy itself but fastened to rings secured to weights at the bottom
at a considerable distance apart, the lateral movement might, no
doubt, be minimised; and for very simple installations this plan,
associated with the device of taking a cable from the buoy and turning
it several times round a drum on shore, could be used to furnish a
convenient source of cheap power. The drum may carry a crank and
shaft, which works the spur-wheel and toothed bands as already
described, so that no matter at what stage in the revolution of the
drum an upward or downward stroke may be stopped, the motion will
still be communicated in a continuous rotary form to the fly-wheel.

But the beam and sliding frame, with buoys, give the best practical
results, especially for large installations. It is in some instances
advisable, especially where the depth of the water at a convenient
distance from the shore is very considerable, not to provide a single
beam reaching the whole distance to the bottom, but to anchor an
air-tight tank below the surface and well beneath the depth at which
wave disturbance is ever felt. From this submerged tank, which
approximately keeps a steady position in all tides and weathers, the
upward beam is attached by a ring just as would be done if the tank
itself constituted the bottom.

One main reason for this arrangement is that the resistance of the
beam to the water as it rocks backwards and forwards wastes to some
extent the power generated by the force of the waves; and the greater
the length of the beam, the longer must be the distance through which
it has to travel when the buoys draw it into positions vertical to
that of the framework. A thin steel pipe offers less resistance than a
wooden beam of equal strength, besides facilitating the use of a
simple device for enabling the frame and buoys to slide easily up and
down.

The generally fatal defect of those inventions which have been
designed in the past with the object of utilising wave-power has
arisen from the mistake of placing too much of the machinery in the
sea. The device of erecting in the water an adjustable reservoir to
catch the wave crests and to use the power derived from them as the
water escaped through a water-wheel was patented in 1869. Nearly
twenty years later another scheme was brought out depending upon the
working of a large pump fixed far under the surface, and connected
with the shore so that, when operated by the rising and falling of
floats upon the waves, it would drive a supply of water into an
elevated reservoir on shore, from which, on escaping down the cliff,
the pressure of the water would be utilised to work a turbine.

Earlier devices included the building of a mill upon a rocking barge,
having weights and pulleys adjusted to run the machinery on board; and
also a revolving float so constructed that each successive wave would
turn one portion, but the latter would then be held firm by a toothed
wheel and ratchet until another impulse would be given to it in the
same direction. This plan included certain elements of the simple
system already described; but it is obvious that some of its floating
parts might with advantage have been removed to the shore end, where
they would not only be available for ready inspection and adjustment,
but also be out of harm's way in rough weather.

Different wave-lengths, as already explained, correspond to various
periods in the pendulous swing of floating bodies. Examples have been
cited by Mr. Vaughan Cornish, M. Sc., in _Knowledge_, 2nd March, 1896,
as follows: "A wave-length of fifty feet corresponds to a period of
two and a half seconds, while one of 310 feet corresponds to five and
a half seconds. It is mentioned that the swing of the steam-ship
_Great Eastern_ took six seconds." Other authorities state that during
a storm in the Atlantic the velocity of the wave was determined to be
thirty-two miles an hour, and that nine or ten waves were included in
each mile; thus about five would pass in each minute. But in average
weather the number of waves to the mile is considerably larger, say,
from fifteen to twenty to the mile; and in nearly calm days about
double those numbers.

One interesting fact, which gives to wave-power a peculiarly enhanced
value as a source of stored wind-power, is that the surface of the
ocean--wild as it may at times appear--is not moved by such extremes
of agitation as the atmosphere. In a calm it is never so inertly
still, and in a storm it is never so far beyond the normal condition
in its agitation as is the wind. The ocean surface to some extent
operates as the governor of a steam-engine, checking an excess in
either direction. In very moderate weather the number of waves to the
mile is greatly increased, while their speed is not very much
diminished. Indeed the rate at which they travel may even be
increased.

This latter phenomenon generally occurs when long ocean rollers pass
out of a region of high wind into one of relative calm, the energy
remaining for a long time comparatively constant by reason of the
multiplication of short, low waves created out of long, high ones. On
all ocean coasts the normal condition of the surface is governed by
this law, and it follows that, no matter what the local weather may be
at any given time, there is always plenty of power available.

An attempt was made by M. C. Antoine, after a long series of
observations, to establish a general relation between the speed of the
wind and that of the waves caused by it, the formulæ being published
in the _Revue Nautique et Coloniale_ in 1879. The rule may be taken as
correct within certain limits, although in calm weather, when the
condition of the ocean surface is almost entirely ruled by distant
disturbances, it has but little relevancy. Approximately, the velocity
of wave transmission is seven times the fourth root of the wind-speed;
so that when the latter is a brisk breeze of sixteen miles an hour the
waves will be travelling fourteen miles an hour, or very nearly as
fast as the wind. When, on the other hand, a light breeze of nine
miles an hour is driving the waves, the latter, according to the
formula, should run about twelve and a half miles an hour; but, in
point of fact, the influence of more distant commotion nearly always
interferes with this result.

As a matter of experience, the waves on an ocean coast are usually
running faster than the wind, and, being so much more numerous in
calm than they are in rough weather, they maintain comparatively a
uniform sum total of energy. It is obvious that, so far as practical
purposes are concerned, three waves of an available height of three
feet each are as effective as one of nine feet. If the state of the
weather be such that the average wave length is 176 feet there will be
exactly thirty waves to the mile, and if the speed be twelve miles an
hour--that is to say, if an expanse of twelve miles of waves pass a
given point hourly--then 360 waves will pass every sixty minutes, or
six every minute. In the wave-power plant as described, each buoy of
one hundred tons displacement when raised and depressed, say, three
feet by every wave will thus be capable of giving power equal to three
times 600, or 1,800 foot-tons per minute.

The unit of nominal horse-power being 33,000 foot-pounds or about
fifteen foot-tons per minute, it is evident that each buoy, at its
maximum, would be capable of giving about 120 horse-power. Supposing
that half of the possible energy were exerted at the forward and half
at the backward stroke and that each buoy were always in position to
exert its full power upon the uprising shaft without deduction, the
total effective duty of a machine such as has been described would be
480 horse-power. In practice, however, the available duty would
probably, according to minor circumstances, be rather more or rather
less than 300 horse-power.




                            CHAPTER III.

                          STORAGE OF POWER.


The three principal forms of stored power which are now in sight above
the horizon of the industrial outlook are the electric storage
battery, compressed air, and calcium-carbide. The first of these has
come largely into use owing to the demand for a regulated and stored
supply of electricity available for lighting purposes. Indeed the
storage battery has practically rendered safe the wide introduction of
electric lighting, because a number of cells, when once charged, are
always available as a reserve in case of any failure in the power or
in the generators at any central station; and also because, by means
of the storage cells or "accumulators," the amount of available
electrical energy can be subdivided into different and subordinate
circuits, thus obviating the necessity for the employment of currents
of very high voltage and eluding the only imperfectly-solved problem
of dividing a current traversing a wire as conveniently as lighting
gas is divided by taking small pipes off from the gas mains.

Compressed air for the storage of power has hitherto been best
appreciated in mining operations, one of the main reasons for this
being that the liberated air itself--apart from the power which it
conveyed and stored--has been so great a boon to the miner working in
ill-ventilated stopes and drives. The cooling effects of the
expansion, after close compression, are also very grateful to men
labouring hard at very great depths, where the heat from the country
rock would become, in the absence of such artificial refrigeration,
almost overpowering. For underground railway traffic exactly the same
recommendations have, at one period during the fourth quarter of the
nineteenth century, given an adventitious stimulus to the use of
compressed air.

Yet it is now undoubted that, even in deep mining, the engineer's best
policy is to adopt different methods for the conveyance and storage of
power on the one hand, and for the ventilation of the workings on the
other. Few temptations are more illusory in the course of industrial
progress than those presented by that class of inventions which aim at
"killing two birds with one stone". If one object be successfully
accomplished it almost invariably happens that the other is
indifferently carried out; but the most frequent result is that both
of them suffer in the attempt to adapt machinery to irreconcilable
purposes.

The electric rock-drill is now winning its way into the mines which
are ventilated with comparative ease as well as into those which are
more difficult to supply with air. It is plain, therefore, that on its
merits as a conveyer and storer of power the electric current is
preferable to compressed air. The heat that is generated and then
dissipated in the compression of any gas for such a purpose represents
a very serious loss of power; and it is altogether an insufficient
excuse to point to the compensation of coolness being secured from the
expansion. Fans driven by electric motors already offer a better
solution of the ventilation difficulty, and the advantages on this
side are certain to increase rather than to diminish during the next
few years.

The electric rock-drill, which can already hold its own with that
driven by compressed air, is therefore bound to gain ground in the
future. This is a type and indication of what will happen all along
the industrial line, the electric current taking the place of the
majority of other means adopted for the transmission of power. Even in
workshops--where it is important to have a wide distribution of power
and each man must be able to turn on a supply of it to his bench at
any moment--shafting is being displaced by electric cables for the
conveyance of power to numerous small motors.

The loss of power in this system has already been reduced to less than
that which occurs with shafting, unless under the most favourable
circumstances; and in places where the works are necessarily
distributed over a considerable area the advantage is so pronounced
that hardly any factories of that kind will be erected ten years hence
without resort being had to electricity, and small motors as the means
of distributing the requisite supplies of power to the spots where
they are needed. It was a significant fact that at the Paris
Exposition of 1900 the electric system of distribution was adopted.

In regard to compressed air, however, it seems practically certain
that, notwithstanding its inferiority to electric storage of power, it
is applicable to so many kinds of small and cheap installations that,
on the whole, its area of usefulness, instead of being restricted,
will be largely increased in the near future. There will be an advance
all along the line; and although electric storage will far outstrip
compressed air for the purposes of the large manufacturer, the air
reservoir will prove highly useful in isolated situations, and
particularly for agricultural work.

For example, as an adjunct to the ordinary rural windmill for pumping
water, it will prove much more handy and effective than the system at
present in vogue of keeping large tanks on hand for the purpose of
ensuring a supply of water during periods of calm weather. Regarding a
tank of water elevated above the ground and filled from a well as
representing so much stored energy, and also comparing this with an
equal bulk of air compressed to about 300 pounds pressure to the
square inch, it would be easy to show that--unless the water has been
pumped from a very deep well--the power which its elevation indicates
must be only a small fraction of that enclosed in the air reservoir.

It will be one great point in favour of compressed air, as a form of
stored energy for the special purpose of pumping, that by making a
continuous small flow of air take the place of the water at the lowest
level in the upward pipe, it is possible to cause it to do the pumping
without the intervention of any motor.

One means of effecting this may be simply indicated. The air under
pressure is admitted from a very small air pipe and the bubbles, as
they rise, fill the hollow of an inverted iron cup rising and falling
on a bearing like a hinge. Above and beneath the chamber containing
this cup are valves opening upwards and similar to those of an
ordinary force or suction pump. The cup must be weighted with
adjustable weights so that it will not rise until quite full of air.
When that point is reached the stroke is completed, the air having
driven upwards a quantity of water of equal bulk with itself, and, as
the cup falls again by its own weight, the vacuum caused by the air
escaping upwards through the pipe is filled by an inrush of water
through the lower valve. The function of the upper valve, at that
time, is to keep the water in the pipe from falling when the pressure
on the column is removed. The expansive power of the air enables it to
do more lifting at the upper than at the lower level, so that a larger
diameter of pipe can be used at the former place.

Cheap motors working on the same principle--that is to say through the
upward escape of compressed air, gas or vapour filling a cup and
operating it by its buoyancy, or turning a wheel in a similar
manner--will doubtless be a feature in the machine work of the future;
and for motors of this description it is obvious that compressed air
will be very useful as the form of power-storage. Excepting under
very special conditions, steam is not available for such a purpose,
seeing that it condenses long before it has risen any material
distance in a column of cold water.

"The present accumulator," remarked Prof. Sylvanus P. Thompson in the
year 1881, referring to the Faure storage batteries then in use,
"probably bears as much resemblance to the future accumulator as a
glass bell-jar used in chemical experiments for holding gas does to
the gasometer of a city gasworks, or James Watt's first model
steam-engine does to the engines of an Atlantic steamer." When Faure,
having in 1880 improved upon the storage battery of Planté, sent his
four-cell battery from Paris to Glasgow, carrying in it stored
electrical energy, it was found to contain power equal to close upon a
million foot-pounds, which is about the work done by a horse-power
during the space of half an hour. This battery weighed very nearly 75
lb. It nevertheless represented an immense forward step in the problem
of compressing a given quantity of potential power into a small weight
of accumulator.

The progress made during less than twenty years to the end of the
century may be estimated from the conditions laid down by the
Automobile Club of Paris for the competitive test of accumulators
applicable to auto-car purposes in 1899. It was stipulated that five
cells, weighing in all 244 lb., should give out 120 ampere-hours of
electric intensity; and that at the conclusion of the test there
should remain a voltage of 1·7 volt per cell.

Very great improvements in the construction of electric accumulators
are to be looked for in the near future. Hitherto the average duration
of the life of a storage cell has not been more than about two years;
and where impurities have been present in the sulphuric acid, or in
the litharge or "minium" employed, the term of durability has been
still further shortened. It must be remembered that while the
principal chemical and electrical action in the cell is a circular
one,--that is to say, the plates and liquids get back to the original
condition from which they started when beginning work in a given
period,--there is also a progressive minor action depending upon the
impurities that may be present. Such a reagent, for instance, as
nitric acid has an extremely injurious effect upon the plates.

During the first decade after Planté and Faure had made their original
discoveries, the main drawback to the advancement of the electric
accumulator for the storage of power owed its existence to the lack of
precise knowledge, among those placed in charge of storage batteries,
as to the destructive effects of impurities in the cells. It is,
however, now the rule that all acids and all samples of water used for
the purpose must be carefully tested before adoption, and this
practice, in itself, has greatly prolonged the average life of the
accumulator cell.

The era of the large electric accumulator of the kind foreshadowed by
Prof. Sylvanus P. Thompson has not yet arrived, the simple reason
being that electric power storage--apart from the special purposes of
the subdivision and transmission for lighting--has not yet been tried
on a large scale. For the regulation and graduation of power it is
exceedingly handy to be able to "switch-on" a number of small
accumulator cells for any particular purpose; and, of course, the
degree of control held in the hands of the engineer must depend
largely on the smallness of each individual cell, and the number which
he has at command. This fact of itself tends to keep down the size of
the storage cell which is most popular.

But when power storage by means of the electric accumulator really
begins in earnest the cells will attain to what would at present be
regarded as mammoth proportions; and the special purpose aimed at in
each instance of power installation will be the securing of
continuity in the working of a machine depending upon some
intermittent natural force. Windmills are especially marked out as the
engines which will be used to put electrical energy into the
accumulators. From these latter again the power will be given out and
conveyed to a distance continuously.

High ridges and eminences of all kinds will in the future be selected
as the sites of wind-power and accumulator plants. In the eighteenth
century, when the corn from the wheat-field required to be ground into
flour by the agency of wind-power, it was customary to build the mill
on the top of some high hill and to cart all the material laboriously
to the eminence. In the installations of the future the power will be
brought to the material rather than the material to the power. From
the ranges or mountain peaks, and also from smaller hills, will
radiate electrical power-nerves branching out into network on the
plains and supplying power for almost every purpose to which man
applies physical force or electro-chemical energy.

The gas-engine during the twentieth century will vigorously dispute
the field against electrical storage; and its success in the
struggle--so far as regards its own particular province--will be
enhanced owing to the fact that, in some respects, it will be able to
command the services of electricity as its handmaid. Gas-engines are
already very largely used as the actuators of electric lighting
machinery. But in the developments which are now foreshadowed by the
advent of acetylene gas the relation will be reversed. In other words,
the gas-engine will owe its supply of cheap fuel to the electric
current derived at small expense from natural sources of power.

Calcium carbide, by means of which acetylene gas is obtained as a
product from water, becomes in this view stored power. The
marvellously cheap "water-gas" which is made through a jet of steam
impinging upon incandescent carbons or upon other suitable glowing hot
materials will, no doubt, for a long time command the market after the
date at which coal-gas for the generation of power has been partially
superseded.

But it seems exceedingly probable that a compromise will ultimately be
effected between the methods adopted for making water-gas and calcium
carbide respectively, the electric current being employed to keep the
carbons incandescent. When power is to be sold in concrete form it
will be made up as calcium carbide, so that it can be conveyed to any
place where it is required without the assistance of either pipes or
wires. But when the laying of the latter is practicable--as it will be
in the majority of instances--the gas for an engine will be obtainable
without the need for forcing lime to combine with carbon as in calcium
carbide.

Petroleum oil is estimated to supply power at just one-third the price
of acetylene gas made with calcium carbide at a price of £20 per ton.
This calculation was drawn up before the occurrence of the material
rise in the price of "petrol" in the last year of the nineteenth
century; while, concurrently, the price of calcium carbide was
falling. A similar process will, on the average, be maintained
throughout each decade; and, as larger plants, with cheaper natural
sources of energy, are brought into requisition, the costs of power,
as obtained from oil and from acetylene gas, will more and more
closely approximate, until, in course of time, they will be about
equal; after which, no doubt, the relative positions will be reversed,
although not perhaps in the same ratio. Time is all on the side of the
agent which depends for its cheapness of production on the utilisation
of any natural source of power which is free of all cost save
interest, wear and tear, and supervision.

Even the steam-engine itself is not exempt from the operation of the
general law placing the growing advantage on the side of power that is
obtainable gratis. One cubic inch of water converted into steam and at
boiling point will raise a ton weight to the height of one foot; and
the quantity of coal of good quality needed for the transformation of
the water is very small. One pound of good coal will evaporate nine
pounds of water, equal to about 250 cubic inches, this doing 250
foot-tons of work. But Niagara performs the same amount of work at
infinitely less cost. However small any quantity may be, its ratio to
nothing is infinity.

It has been the custom during the nineteenth century to institute
comparisons between the marvellous economy of steam power and the
expensive wastefulness of human muscular effort. For instance, the
full day's work of an Eastern porter, specially trained to carry heavy
weights, will generally amount to the removal of a load of from three
to five hundred-weight for a distance of one mile; but such a labourer
in the course of a long day has only expended as much power as would
be stored up in about five ounces of coal.

Still the fact remains that one of the greatest problems of the future
is that which concerns the reduction in the cost of power. Hundreds
of millions of the human race pass lives of a kind of dull monotonous
toil which develops only the muscular, at the expense of the higher,
faculties of the body; they are almost entirely cut off from social
intercourse with their fellow-men, and they sink prematurely into
decrepitude simply by reason of the lack of a cheap and abundant
supply of mechanical power, ready at hand wherever it is wanted.
Scores of "enterprises of great pith and moment" in the industrial
advancement of the world have to be abandoned by reason of the same
lack. In mining, in agriculture, in transport and in manufacture the
thing that is needful to convert the "human machine" into a more or
less intelligent brainworker is cheaper power. All the technical
education in the world will not avail to raise the labourer in the
intellectual scale if his daily work be only such as a horse or an
engine might perform.

The transmission of power through the medium of the electric current
will naturally attain its first great development in the
neighbourhoods of large waterfalls such as Niagara. When the
manufacturers within a short radius of the source of power in each
case have begun to fully reap the benefit due to cheap power,
competition will assert itself in many different ways. The values of
real property will rise, and population will tend to become congested
within the localities' served.

It will be found, however, that facilities for shipment will to a
large extent perpetuate the advantage at present held by manufactories
situated on ports and harbours; and this, of course, will apply with
peculiar force to the cases of articles of considerable bulk. Where a
very great deal of power is needed for the making of an article or
material of comparatively small weight and bulk proportioned to its
value--such for instance as calcium carbide or aluminium--the
immediate vicinity of the source of natural power will offer
superlative inducements. But an immense number of things lie between
the domains of these two classes, and for the economical manufacture
of these it is imperative that both cheap power and low wharfage rates
should be obtainable.

An increasingly intense demand must thus spring up for systems of long
distance transmission, and very high voltage will be adopted as the
means of diminishing the loss of power due to leakage from the cables.
Similarly the "polyphase" system--which is eminently adapted to
installations of the nature indicated--must demand increasing
attention.

Taking a concrete example, mention may be made of the effects to be
expected from the proposed scheme for diverting some of the headwaters
of the Tay and its lakes from the eastern to the western shores of
Scotland and establishing at Loch Leven--the western inlet, not the
inland lake of that name--a seaport town devoted to manufacturing
purposes requiring very cheap supplies of power. It is obvious that
the owners of mills in and around Glasgow, and only forty or fifty
miles distant, will make the most strenuous exertions to enable them
to secure a similar advantage.

It is already claimed that with the use of currents of high voltage
for carrying the power, and "step-down transformers" converting these
into a suitable medium for the driving of machinery, a fairly
economical transmission can be ensured along a distance of 100 miles.
It therefore seems plain that the natural forces derived from such
sources as waterfalls can safely be reckoned upon as friends rather
than as foes of the vested interests of all the great cities of the
United Kingdom.

The possibilities of long distance transmission are greatly enhanced
by the very recent discovery that a cable carrying a current of high
voltage can be most effectually insulated by encasing it in the midst
of a tube filled with wet sawdust and kept at a low temperature,
preferably at the freezing point of water.

Wireless transmission of a small amount of power has been proved to be
experimentally possible. In the rarefied atmosphere at a height of
five or ten miles from the earth's surface, electric discharges of
very high voltage are conveyed without any other conducting medium
than that of the air. By sending up balloons, carrying suspended
wires, the positions of despatch and of receipt can be so elevated
that the resistance of the atmosphere can be almost indefinitely
diminished. In this way small motors have been worked by discharges
generated at considerable distances, and absolutely without the
existence of any connection by metallic conductors. Possibilities of
the exportation of power from suitable stations--such as the
neighbourhoods of waterfalls--and its transmission for distances of
hundreds or even thousands of miles have been spoken of in relation to
the industrial prospects of the twentieth century.

Comparing any such hypothetical system with that of sending power
along good metallic conductors, there is at once apparent a very
serious objection in the needless dispersion of energy throughout
space in every direction. If a power generator by wireless
transmission, without any metallic connection, can work one motor at
a distance of, say, 1,000 miles, then it can also operate millions of
similar possible motors situated at the same distance; and by far the
greater part of its electro-motive force must be wasted in upward
dispersion.

The analogy of the wireless transmitter of intelligence may be
misleading if applied to the question of power. The practicability of
wireless telegraphy depends upon the marvellous susceptibility of the
"coherer," which enables it to respond to an impulse almost
infinitesimally small, certainly very much smaller than that
despatched by the generator from the receiving station. From this it
follows, as already stated, that the analogy of apparatus designed
merely for the despatch of intelligence by signalling cannot safely be
applied to the case of the transmission of energy.

Making all due allowances for the prospects of advance in minimising
the resistance of the atmosphere, it must nevertheless be remembered
that any wireless system will be called upon to compete with improved
means of conveying the electric current along metallic circuits.
Electrical science, moreover, is only at the commencement of its work
in economising the cost of power-cables.

The invention by which one wire can be used to convey the return
current of two cables very much larger in sectional area is only one
instance in point. The two major cables carry currents running in
opposite directions, and as these currents are both caused to return
along the third and smaller wire their electro-motive forces balance
one another, with the result that the return wire needs only to carry
a small difference-current. The return wire, in fact, is analogous to
the Banking Clearing House, which deals with balances only, and which
therefore can sometimes adjust business to the value of many millions
with payments of only a few thousands. Later on it may fairly be
expected that duplicate and quadruplicate telegraphy will find its
counterpart in systems by which different series of electrical
impulses of high voltage will run along a wire, the one alternating
with the other and each series filling up the gaps left between the
others.




                              CHAPTER IV.

                           ARTIFICIAL POWER.


The steam-turbine is the most clearly visible of the revolutionary
agencies in motors using the artificial sources of power. In the first
attempts to introduce the principle the false analogy of the
water-turbine gave rise to much waste of inventive energy and of
money; but the more recent and more distinctly successful types of
machine have been constructed with a clear understanding that the
windmill is the true precursor of the steam-turbine. It is clearly
perceived that, although it may be convenient and even essential to
reduce the arms to pigmy dimensions and to enclose them in a tube,
still the general principle of the machine must resemble that of a
number of wind motors all running on the same shaft.

It has been proved, moreover, that this multiplicity of minute wheels
and arms has a very distinct advantage in that it renders possible the
utilisation of the expansive power of steam. The first impact is small
in area but intense in force, while those arms which receive the
expanded steam further on are larger in size as suited to making the
best use of a weaker force distributed over a greater amount of space.

The enormous speed at which steam under heavy pressure rushes out of
an orifice was not duly appreciated by the first experimenters in this
direction. To obtain the best results in utilising the power from
escaping steam there must be a certain definite proportion between the
speed of the vapour and that of the vane or arm against which it
strikes. In other words, the latter must not "smash" the jet, but must
run along with it. In the case of the windmill the ratio has been
stated approximately by the generalisation that the velocity of the
tips of the sails is about two and a half times that of the wind. This
refers to the old style of windmill as used for grinding corn.

The steam turbine must, therefore, be essentially a motor of very
great initial speed; and the efforts of recent inventors have been
wisely directed in the first instance to the object of applying it to
those purposes for which machinery could be coupled up to the motor
with little, if any, necessity for slowing down the motion through
such appliances as belting, toothed wheels, or other forms of
intermediate gearing. The dynamo for electric lighting naturally first
suggested itself; but even in this application it was found necessary
to adopt a rate of speed considerably lower than that which the steam
imparts to the turbine; and, unfortunately, it is exactly in the
arrangement of the gear for the first slowing-down that the main
difficulty comes in.

Nearly parallel is the case of the cream separator, to which the
steam-turbine principle has been applied with a certain degree of
success. By means of fine flexible steel shafts running in bearings
swathed in oil it has been found possible to utilise the comparatively
feeble force of a small steam jet operating at immense speed to
produce one of much slower rate but enormously greater strength. Some
success has been achieved also in using the principle not only for
cream separators, which require a comparatively high velocity, but for
other purposes connected with the rural and manufacturing industries.

An immense forward stride, however, was made when the idea was first
conceived of a steam-turbine and a water-turbine being fixed on the
same shaft and the latter being used for the propulsion of a vessel at
sea. In this case it is obvious that, by a suitable adjustment of the
pitch of screw adopted in both cases, a nice mathematical agreement
between the vapour power and the liquid application of that power can
be ensured.

All previous records of speed have been eclipsed by the turbine-driven
steamers engined on this principle. Through the abolition of the
principal causes of excessive vibration--which renders dangerous the
enlargement of marine reciprocating engines beyond a certain size--the
final limit of possible speed has been indefinitely extended. The
comfort of the passenger, equally with the safety of the hull, demands
the diminution of the vibration nuisance in modern steamships, and
whether the first attempts to cater for the need by turbine-engines be
fully successful or not, there is no doubt whatever that the fast mail
packets of the future will be driven by steam-engines constructed on a
system in which the turbine principle will form an important part.

Further applications will soon follow. It is clear that if the
steam-turbine can be advantageously used for the driving of a vessel
through the water, then, conversely, it can be similarly applied to
the creation of a current of water or of any other suitable liquid.
This liquid-current, again, is applicable to the driving of machinery
at any rate that may be desired. In this view the slowing-down
process, which involves elaborate and delicate machinery when
accomplished in the purely mechanical method, can be much more
economically effected through the friction of fluid particles.

One method of achieving this object is an arrangement in which the
escaping steam drives a turbine-shaft running through a long tube and
passing into the water in a circular tank, in which, again, the shaft
carries a spiral or turbine screw for propelling the water. The
arrangement, it will be seen, is strictly analogous to that of the
steam-turbine as used in marine propulsion, the shaft passing through
the side of the tank just as it does through the stern of the vessel.

One essential point, however, is that the line of the shaft must not
pass through the centre of the circular tank, but must form the chord
of an arc, so that when the water is driven against the side by the
revolution of the screw it acts like a tangential jet. Practically the
water is thus kept in motion just as it would be if a hose with a
strong jet of water were inserted and caused to play at an obtuse
angle against the inner side.

Motion having been imparted to the fluid in the tank, a simple device
such as a paddle-wheel immersed at its lower end, may be adopted for
taking up the power and passing it on to the machinery required to be
actuated. By setting both the shaft carrying the vanes for the
steam-turbine and the screw for the propulsion of the water at a
downward inclination it becomes practicable to drive the fluid without
requiring any hole in the tank; and in this case the latter may be
shaped in annular form and pivoted so that it becomes a horizontal
fly-wheel. Obstructing projections on the inside periphery of the
annular tank assist the water to carry the latter along with it in its
circular motion.

For small steam motors, particularly for agricultural and domestic
purposes, the turbine principle is destined to render services of the
utmost importance. The prospect of its extremely economical
construction depends largely upon the fact that, with the exception of
two or three very small bearings carrying narrow shafts, it contains
no parts demanding the same fine finish as does the cylinder of a
reciprocating engine. It solves in a very simple manner the much-vexed
problem of the rotary engine, upon which so much ingenuity has been
fruitlessly exercised. The steam-turbine also has shown that, for
taking advantage of the generation and the expansive power of steam,
there is no absolute necessity for including a steam-tight chamber
with moving parts in the machine.

For very small motors suitable for working fans and working other
household appliances, the use of a jet of steam, applied directly to
drive a small annular fly-wheel filled with mercury--without the
intervention of any turbine--will no doubt prove handy. But in the
economy of the future such appliances will take the place of
electrical machinery only in exceptional situations.

One promising use of the turbine or steam-jet--used to propel a
fly-wheel filled with liquid as described--has for its object the
supply of the electric light in country houses. In this case the
fly-wheel is fitted, on its lower side, to act as the armature of a
dynamo, and the magnets are placed horizontally around it.

The full effective power from a jet of steam is not communicated to a
dynamo for electric lighting or other purposes unless there be a
definite ratio between the speeds of the turbine and of the armature
respectively. This may be conveniently provided for, with more
precision and in a less elaborate way than that which has just been
described, if the steam jet be made to drive a vertically pendant
turbine, the lower extremity of which, carrying very small horizontal
paddles, must be inserted into the centre of a circular tank.

The principle upon which the reduction of speed necessary for the
dynamo is then effected depends upon the fact that in a whirlpool the
liquid near the centre runs nearly as fast as that on the outer
periphery, and therefore--the circles being so very much smaller--the
number of revolutions effected in a given time is much greater. Thus a
steam jet turning a pendant turbine--dipping into the middle of the
whirlpool and carrying paddles--at an enormously high speed may be
made to impart motion to the water in a circular tank (or, if desired,
to the tank itself) at a very much slower rate; the amount of the
reduction, of course, depending mainly on the ratio between the
diameter of the tank and the length of the small paddles at the centre
setting the liquid in motion.

For special purposes it is best to substitute a spherical for an
ordinary circular tank and the size may be greatly diminished by using
mercury instead of water. The sphere is complete, excepting for a
small aperture at the top for the admission of the steel shaft of the
steam-driven turbine. No matter how high may be the speed, the liquid
cannot be thrown out from a spherical revolving receptacle constructed
in this way. Moreover, the mercury acts not only as a transmitter of
the power from the turbine to the purpose for which it is wanted, but
also as a governor. Whenever the speed becomes so great as to throw
the liquid entirely into the sides of the sphere--so that the shaft
and paddles are running free of contact with it in the middle--the
machine slows down, and it cannot again attain full speed until the
same conditions recur.

The rate of speed which may be worked up to as a maximum is determined
by the position of the paddle-wheel, which is adjustable and floats
upon the liquid although controlled in its circular motion by the
shaft which passes through a square aperture in it and also a sleeve
extending upward from it. The duty of the latter is to economise steam
by cutting off the jet as soon as, by its rapidity of motion, the
paddle-wheel has thrown the mercury to the sides to such an extent as
to sink to a certain level in the centre.

Cheap motors coupled with cheap dynamos will, in the twentieth
century, go far towards lightening the labours of millions whose toil
is at present far too much of a mere mechanical nature. The dynamo
itself, however, requires to be greatly reduced in first cost.
Particularly it is necessary that the expense involved in drawing the
wire, insulating it, and winding machines with it, should be
diminished. This will no doubt be partly accomplished by the
electrolytic producers of copper when once they get properly started
on methods of depositing thin strips or wires of tough copper on to
sheets of insulating material for wrapping round the magnets and other
effective parts intended for dynamos. There is no fundamental reason
which forbids that when electro deposition is resorted to for the
recovery of a metal from its ore it should be straightway converted to
the shape and to the purpose for which it is ultimately intended. This
consideration has presented itself to the minds of some of the
manufacturers of aluminium, who make many articles intended for
household use electrolytically; and it must affect many other trades
which are concerned in the output and in the working-up of metals
readily susceptible of deposition--more particularly such as copper.

The familiar aneroid barometer furnishes a hint for another convenient
form of small steam-engine. In seeking to cheapen machinery of this
class it is of the utmost importance that the necessity for boring out
cylinders and for planing and other expensive work should be avoided.
In the aneroid barometer a shallow circular box is fitted with a
cover, which is corrugated in concentric circles, and the pressure of
the superincumbent air is caused to depress the centre of this cover
through the device of partially exhausting the box of air and thus
diminishing the internal resistance. To the slightly moving middle
part of the cover is affixed a lever which actuates, after some
intermediate action, the hand which moves on the dial to indicate, by
its record of variations in the weight of the atmosphere, what the
prospect of the weather may be.

In the aneroid form of the steam-engine the cylinder is immensely
widened and flattened, and the broad circular lid, with its spiral
corrugations, takes the place of the piston. The rod, which acts
virtually as a piston-rod, is hollow, and it works into a bearing
which permits the steam to escape when the extreme point of the stroke
has been reached into a separate condensing chamber kept cool with
water. The boiler itself, with corrugated top, may take the place of
the cylinder.

In some respects this little machine represents a retrograde movement,
even from Watt's original engine with its separate condenser; but its
extreme economy of first cost recommends it to poor producers. In the
near future no country homestead will be without its power
installation of one kind or another, and there is room for many types
of cheap motors.

A motor like the steam-turbine is evidently the forerunner of other
engines designed to utilise the force of an emission jet of vapour or
gas. There are very many processes in which gases generated by
chemical combinations are permitted to escape without performing any
services, not even that of giving up the energy which they may be made
to store up when held in compression in a closed vessel.

The reciprocating forms found suitable for steam and gas engines are
hardly adaptable for experiments in the direction of economising this
source of power, one fatal objection in the majority of cases being
the corrosive effects of the gases generated upon the insides of
cylinders and other working parts. As soon as the force of the
emission jet can be applied as a factor in giving motive power, the
fact that no close-fitting parts are required for the places upon
which the line of force impinges will alter the conditions of the
whole problem. In the centrifugal sand pump, as now largely used for
raising silt from rivers and harbours, the serious corrosive action of
the jet of sand and water upon the inside of the pump has been
successfully overcome by facing the metal with indiarubber; but
nothing of the kind could have been done if the working of the
apparatus had depended on the motion of close-fitting parts, as in the
ordinary suction or lift pump.

As an instance of the class of work for which gaseous jets, for
driving turbines or similar forms of motor, may perform useful
services the case of farm-made superphosphate of lime may be cited. By
subjecting bones to the action of sulphuric acid the farmer may
manufacture his own phosphatic manures for the enrichment of his land.
But the carbonic dioxide and other gases generated as the result of
the operation are wasted. Therefore it at present pays better to carry
the bones to the sulphuric acid than to reverse the procedure by
conveying the acid to the farm, where the bones are a by-product.

So bulky are the latter, however, that serious waste of labour is
involved in transporting them for long distances. Calculations made
out by the experts of various state agricultural stations show that,
as a general rule, it is now cheaper for the farmer to buy his
superphosphates ready made than to make them on his farm. The
difference in some cases, however, is not great; and only a
comparative trifle would be needed in order to turn the balance. This
may probably be found in the economic value of the service rendered by
a turbine-engine or other device for utilising the expansive power of
the gases which are driven from the constituents of the bones by the
action of the sulphuric acid.

For pumping water and other ordinary farm operations the chemical
gas-engine will prove very handy; and the great point in its favour
will be that instead of useless cinders the refuse from it will
consist of the most valuable compost with which the farmer can dress
the soil. Enamelled iron will be employed for the troughs in which the
bones and acid will be mixed, and a cover similar to that placed over
a "Papin's digester" will be clamped to the rim all round, the gases
being liberated only in the form of a jet used for driving machinery.

For very small motors, applicable specially to domestic purposes such
as ventilation, there is one source of power which, in all places
within the reticulation areas of waterworks, may be had practically
for nothing. Probably when the owners of water-supply works realise
that they have command of something which is of commercial value,
although hitherto unnoticed, they will arrange to sell not only the
water which they supply, but also the power which can be generated by
its escape when utilised and by the variations in the pressure from
hour to hour and even from minute to minute.

The latter, for such purposes as ventilation, for instance, will no
doubt come to the front sooner than the intermittent power now wasted
by the outflowing of water--a power which is comparatively too small
an item in most cases to compensate for the outlay and trouble of
arranging for the storage of energy. But in the case of the variation
in the pressure, without any escape of water at all, no such
disability appears. Experiments conducted in several of the larger
cities of England with various types of water meters--which are really
motors on a small scale--have proved the practicability of obtaining a
source of constant power from what may be termed the ebb and the flow
of pressure within the pipes of a water supply system.

At every hour of the day there is a marked variation in the quantity
of water that is being drawn away by consumers, and consequently a
rise and fall in the degree of pressure recorded by the meter. In an
apparatus for converting the power derivable from this source to
useful purposes something on a very small scale analogous to that
which has already been described in connection with utilising the
rise and fall of a wave will be found serviceable. A small spur-wheel
is gripped on two sides by two metal laths, with edges serrated like
those of saws, and held against the wheel by gentle pressure. Every
movement of the two saws--whether backwards or forwards--is then
responded to by a continuous circular motion of the wheel, with the
sole exception of those movements which may be too small in extent to
include even as much as a single tooth of the wheel. On this account
it is important that the teeth should be made as numerous as possible
consistently with the amount of pressure which they may have to bear.

Resort may be had to the principle of the aneroid barometer in order
to secure from the water within the pipe-system the energy by which
these saw-like bands are driven up and down with reciprocal motion. A
very shallow circular tank in the shape of a watch is in communication
with the water in the pipes, and its top or covering is composed of a
concentrically-corrugated sheet of finely tempered steel. At the
centre of this is fixed the guide which pushes and pulls the saw-like
laths. Every rise and fall in the pressure of the water now effects a
movement of the spur-wheel, and the latter may conveniently be
connected with the strong spring of a clockwork attachment, so that
the water pressure is really used for winding up a clockwork
ventilating-fan.

In the making of cheap steam and gas engines, as well as in machine
work generally, rapid progress will be made when the possibilities of
producing hard and smooth wearing surfaces without the need for
cutting and filing rough-cast metal have been fully investigated. Many
parts of machinery will be electro-deposited--like the small articles
already mentioned--in aluminium or hard copper at the metallurgical
works where ore is being treated for the recovery of metal, or even at
the mines themselves.

Side by side with this movement there will be one for developing the
system of stamping mild steel and then tempering it. At the same time
also the behaviour of various metals and alloys, not only in the cold
state but also at the critical point between melting and
solidification, will be much more carefully studied so as to take
advantage of every means whereby accurately shaped articles may be
made and finished in the casting. It has been found, for example, that
certain kinds of type metal, if placed under very heavy pressure at
the moment when passing from the liquid to the solid condition, not
only take the exact form of the mould in which they are placed, but
become extremely hard by comparison with the same alloy if permitted
to solidify without pressure.

The example of the cheap watch industry may be cited to convey an idea
of the immensely important revolution which will take place in the
production of both small and large prime-motors when all the
possibilities of electrotyping, casting, and stamping the various
wearing parts true to shape and size have been fully exploited. An
accurate timekeeper is now practically within the reach of all; and in
the twentieth century no one who requires a small prime motor to do
the rough work about home or farm will be compelled to do without it
by reason of poverty--unless, perhaps, he is absolutely destitute and
a fit subject for public charity.

Many domestic industries which were crushed out of existence during
the early part of the nineteenth century will therefore be
resuscitated. The dear steam-engine created the factory system and
brought the operatives to live close together in long rows of
unsightly dwellings, but the cheap engine, in conjunction with the
motor driven by transmitted electricity, will give to the working
people comparative freedom again to live where they please, and to
enjoy the legitimate pleasures both of town and of country.




                              CHAPTER V.

                            ROAD AND RAIL.


The existing keen motor-car rivalry presents one of the most
interesting and instructive mechanical problems which are left still
unsolved by the close of the nineteenth century. The question to be
determined is not so much whether road locomotion by means of
mechanical power is practicable and useful, for, of course, that point
has been settled long ago; indeed it would have been recognised as
settled years before had it not been for the crass legislation of a
quarter of a century since which deliberately drove the first
steam-motors off the road in order to ensure the undisturbed supremacy
of horse traffic. The real point at issue is whether a motor can be
made which shall furnish power for purposes of road locomotion as
cheaply and conveniently as is already done for stationary purposes.

Horse traction, although extremely dear, possesses one qualification
which until the present day has enabled it to outdistance its
mechanical competitors upon ordinary roads. This is its power of
adapting itself, by special effort, to the exigencies caused by the
varying nature of the road. Watch a team of horses pulling a waggon
along an undulating highway, with level stretches of easy going and
here and there a decline or a steep hill. There is a continual
adjustment of the strain which each animal puts upon itself according
to the character of the difficulties which must be surmounted, the
effort varying from nothing at all--when going down a gentle
decline--up to the almost desperate jerk with which the vehicle is
taken over some stony part right on the brow of an eminence. The whip
cracks and by threats and encouragements the driver induces each horse
to put forth, for one brief moment, an effort which could not be
sustained for many minutes save at the peril of utter exhaustion.

When the unit of nominal horse-power was fixed at 33,000 foot-pounds
per minute the work contemplated in the arbitrary standard was
supposed to be such as a horse could go on performing for several
hours. It was, of course, well recognised that any good, upstanding
horse, if urged to a special effort, could perform several times the
indicated amount of work in a minute.

Nevertheless the habit of reckoning steam-power in terms of a unit
drawn from the analogy of the horse undoubtedly tended for many years
to obscure the essential difference between the natures of the two
sources of power. Railroads were built with the object of rendering as
uniform as possible the amount of power required to transport a given
weight of goods or passengers over a specified distance; and
consequently the application of the steam-engine to traffic conducted
on the railway line was a success. Many inventors at once jumped to
the conclusion that, by making some fixed allowance for the greater
roughness of an ordinary road, they would be able to construct a
steam-traction engine that would suit exactly for road traffic. In a
rough and rudimentary way an attempt to provide for the special effort
required at steep or stony places was made by the introduction of a
kind of fly-wheel of extraordinary weight proportionate to the size of
the engine; and the same object was aimed at by increasing the power
of the engine to somewhere near the limit of the possible special
requirements. The consequence was the evolution of an immensely
ponderous and wasteful machine, which for some years only held its
ground within the domain of the heavy work of roadmaking. As a means
of road traction the steam-engine was for half a century almost
entirely discomfited and routed by horse-power, partly owing to this
mechanical defect and partly, as we have seen, through legislative
partisanship.

The explosive type of engine was next called into requisition to do
battle against the living competitor of the engineer's handiwork.
Petroleum and alcohol, when volatilised and mixed with air in due
proportion, form explosive mixtures which are much more nearly
instantaneous in their action than an elastic vapour like steam held
under pressure in a boiler, and liberated to perform its work by
comparatively slow expansion. The petroleum engine, as applied to the
automobile, does its work in a series of jerks which provide for the
unequal degrees of power required to cope with the unevenness of a
road.

As against this, however, there are certain grave defects, due mainly
to the use of highly inflammable oils vapourised at high temperatures;
and these have impressed a large proportion of engineers with a belief
that, in the long run, either electricity or steam will win the day.
Storage batteries are well adapted for meeting the exigencies of the
road, just as they are for those of tramway traffic, because, as soon
as an extra strain is to be met, there is always the resource of
coupling up fresh batteries held in reserve--a process which amounts
to the same as yoking new horses to the vehicle in order to take it up
a hill. In practice, however, it is found that the jerky vibratory
motion of the gasoline automobile provides for this in a way almost as
convenient, although not so pleasant.

The chance of the steam-engine being largely adopted for automobile
work and for road traffic generally depends principally on the
prospects of inventing a form of cylinder--or its equivalent--which
will enable the driver to couple up fresh effective working parts of
his machinery at will, just as may be done with storage batteries. A
new form of steam cylinder designed to provide for this need will
outwardly resemble a long pipe--one being fixed on each lower side of
the vehicle--but inwardly it will be divided into compartments each of
which will have its own separate piston. Practically there will thus
be a series of cylinders having one piston-rod running through them
all, but each having its own piston.

Normally, this machine will run with an admission of steam to only one
or two of the cylinders; but when extra work has to be done the other
cylinders will be called into requisition by the opening of the steam
valves leading to them. Provision can be made for the automatic
working of this adjustment by the introduction of a spring upon the
piston-rod, so arranged that, as soon as the resistance reaches a
certain point, a lever is actuated which opens the valves to admit
steam to the reserve cylinders of the engine. On such occasions, of
course, the consumption of steam must necessarily be greatly
increased; but on the other hand the automatic system of the admission
to each cylinder also results in a shutting off of the steam when
little or no work is required. In fact, with a fully automatic action,
regulating the consumption of steam exactly according to the amount of
force necessary to drive the automobile, it would be possible to work
even a single cylinder to much greater advantage than is done by the
machines generally in use.

So heavy are the storage batteries needed for electric traction of the
road motor-car that practically it is not found convenient to carry
enough of cells to last for more than a twenty-mile run. The batteries
must then either be replaced, or a delay of some three hours must
occur while they are being recharged. The idea of establishing
charging stations at almost every conceivable terminus of a run is
quite chimerical; and, even if hundreds of such stations were
provided for the convenience of the users of electric traction, the
limitation imposed by being forced to follow the established routes
would always give to the non-electric motor an advantage over its
competitor.

The best hope for the storage battery on the automobile rests upon its
convenience as a repository of reserve power in conjunction with such
a prime motor as the steam-engine. A turbine worked by a jet of steam,
as already described, and moving in a magnetic field to generate
electricity for storage in a few cells, is a convenient form in which
steam and electricity can be yoked together in order to secure a power
of just the type suitable for driving an automobile. In the machine
indicated the supply of the motive power is direct from the storage
batteries, which can be coupled up in any required number according to
the exigencies of the road. Automatic gear may be introduced by an
adaptation of the principle already referred to.

In a light road-motor for carrying one or two persons on holiday trips
or business rounds, the quality of adaptability of the source of power
to the sudden demands due to differences of level in the road is not
so absolutely essential as it is in traction engines designed for the
transport of goods over ordinary roads. In the former class of work
the waste of power involved in employing a motor of strength
sufficient to climb hills--although the bulk of the distance to be
travelled is along level roads--may not be at all so serious as to
overbalance the many and manifest advantages of the automobile
principle. At the same time, as has already been indicated, there is
no doubt whatever that when proper automatic shut-off contrivances
have been applied for economising mechanical energy in the passenger
road-motor, an immense impetus will be given to its advancement.

In the road traction-engine the need for what may be termed _effort_
on the part of the mechanism is much greater, more especially as the
competition against horse-traction is conducted on terms so much more
nearly level. A team of strong draught-horses driven by one man on a
well-loaded waggon is a far more economical installation of power than
a two-horse buggy carrying one or two passengers.

The asphalt and macadamised tracks which are now being laid down along
the sides of roads for the convenience of cyclists, are the
significant forerunners of an improvement destined to produce a
revolution in road traffic during the twentieth century. When
automobiles have become very much more numerous, and local
authorities find that the settlement of wealthy or comparatively
well-to-do families in their neighbourhoods may depend very largely
upon the question whether light road-motor traffic may be conveniently
conducted to and from the nearest city, an immense impetus will be
administered to the reasonable efforts made for catering for the
demand for tracks for the accommodation of automobiles, both private
and public.

The tyranny of the railway station will then be to a large extent
mitigated, and suburban or country residents will no longer be
practically compelled to crowd up close to each station on their lines
of railroad. Under existing conditions many of those who travel
fifteen or twenty miles to business every day live just as close to
one another, and with nearly as marked a lack of space for lawn and
garden, as if they lived within the city. The bunchy nature of
settlement promoted by railways must have excited the notice of any
intelligent observer during the past twenty or thirty years--that is
to say since the suburban railroad began to take its place as an
important factor in determining the locating of population.

To a very large extent the automobile will be rather a feeder to the
railway than a rival to it; and all sorts of by-roads and country
lanes will be improved and adapted so as to admit of residents running
into their stations by their own motor-cars and then completing their
journeys by rail. But when this point has been reached, and when
fairly smooth tracks adapted for automobile and cycling traffic have
been laid down all over the country, a very interesting question will
crop up having reference to the practicability of converting these
tracks into highways combining the capabilities both of roads and of
railways.

In an ordinary railroad the functions of the iron or steel rails are
twofold, first to carry the weight of the load, and second to guide
the engine, carriage or truck in the right direction. Now the latter
purpose--in the case of a rail-track never used for high speeds,
especially in going round curves--might be served by the adoption of a
very much lighter weight of rail, if only the carrying of the load
could be otherwise provided for. In fact, if pneumatic-tyre wheels,
running on a fairly smooth asphalt track, were employed to bear the
weight of a vehicle, there would then be no need for more than one
guide-rail, which might readily be fixed in the middle of the track;
but this should preferably be made to resemble the rail of a tram
rather than that of a railroad.

"Every man his own engine-driver" will be a rule which will
undoubtedly require some little social and mechanical adjustment to
carry out within the limits of the public safety. But the automobile,
even in its existing form, makes the task of completing this
adjustment practically a certainty of the near future; and as soon as
it is seen that motor tracks with guide lines render traffic safer
than it is on ordinary roads, the main objections to the innovation
will be rapidly overcome. The rule of the road for such guide-line
tracks will probably be based very closely on that which at present
exists for ordinary thoroughfares. On those roads where two tracks
have been laid down each motor will be required to keep to the left,
and when a traveller coming up behind is impatient at the slow rate of
speed adopted by his precursor he will be compelled to make the
necessary détour himself, passing into the middle of the thoroughfare
and there outstripping the party in front, without the assistance of
the guide-rail, and rejoining the track.

To execute this movement, of course, the motor wheels for the
guide-tracks must be mounted on entirely different principles from
those adapted for railroad traffic. The broad and soft tyred wheels
which bear upon the asphalt track will be entrusted with the duty of
carrying the machine without extraneous aid; but there will be two
extra wheels, one in front and one at the rear, capable of being
lifted at any time by means of a lever controlled by the driver. These
guiding wheels will fit into the groove of the tram line in the
centre, being made of a shape suitable for enabling the driver to pick
up the groove quickly whenever he pleases. The carrying wheels of the
vehicle in this system are enabled to pass over the guide-rail
readily, because the latter does not stand up from the track like the
line in a railroad.

A simpler plan, particularly adapted for roads which are to have only
a single guide-rail, is to place the rail at the off-side of the
track, and to raise it a few inches from the ground. The wheels for
the rail are attached to arms which can be raised and lifted off the
rail by the driver operating a lever. Guiding irons, forming an
inverted Y, are placed below the bearings of the wheels to facilitate
the picking up of the rail, their effect being that, if the driver
places his vehicle in approximately the position for engaging the side
wheels with the rail and then goes slowly ahead, he will very quickly
be drawn into the correct alignment. Of course the rails for this kind
of track can be very light and inexpensive in comparison with those
required for railroads on which the whole weight of each vehicle, as
well as the lateral strain caused by its guidance, must fall upon the
rail itself.

The asphalt track and its equivalent will be the means of bringing
much nearer to fulfilment the dream of having "a railway to every
man's door". Many such tracks will be equipped with electric cables as
well as guiding-rails, so that cars with electric motors will be
available for running on them, and the power will be supplied from a
publicly-maintained station. Some difficulty may at first be
experienced in adjusting the rates and modes of payment for the
facilities thus offered; but a convenient precedent is present to hand
in the class of enactment under which tramway companies are at present
protected from having their permanent ways used by vehicles owned by
other persons. Practically the possession of a vehicle having a
flanged wheel and a gauge exactly the same as that of the tram lines
in the vicinity may be taken to indicate an intention to use the
lines. Similarly a certain relation between the positions of guiding
wheels and those of the connections with cables may be held to furnish
evidence of liability to contribute towards the maintenance of
motor-tracks.

Roads and railways will be much more closely inter-related in the
future than they have been in the past. The competition of the
automobile would in itself be practically sufficient to force the
owners of railways into a more adaptive mood in regard to the true
relations between the world's great highways. The way in which the
course of evolution will work the problem out may be indicated
thus:--First, the owners of automobiles will find it convenient in
many instances to run by road to the nearest railway station which
suits their purposes, leaving their machines in charge of the
stationmaster and going on by train. In course of time the owners of
"omnibus automobiles" will desire to secure the same advantage for
their customers, and on this account the road cars will await the
arrival and departure of every train just as horse vehicles do at
present. The next step will be taken by the railway companies, or by
the local authorities, when it becomes obvious that there is much more
profit in motor traffic than there ever was in catering for the public
by means of vehicles drawn by horses. Each important railway station
will have its diverging lines of motor-traffic for the convenience of
passengers, some of them owned and managed by the same authority as
the railway line itself.

Rivalry will shortly enforce an improvement upon this system, because
in the keen competition between railway lines those stations will
attract the best parts of the trade at which the passengers are put to
the smallest amount of inconvenience. The necessity for changing
trains, with its attendant bustle of looking after luggage, perhaps
during very inclement weather, always acts as a hindrance to the
popularity of a line. When "motor-omnibuses" are running by road all
the way into the city, setting people down almost at their doors and
making wide circuits by road, the proprietors of these vehicles will
make the most of their advantages in offering to travellers a cosy and
comfortable retreat during the whole of their journey.

Road-motors, comfortably furnished, will therefore be mounted upon low
railway trucks of special construction, designed to permit of their
being run on and off the trucks from the level of the ground. The plan
of mounting a road vehicle upon a truck suited to receive it has
already been adopted for some purposes, notably for the removal of
furniture and similar goods; and it is capable of immense extension.
An express train will run through on the leading routes from which
roads branch out in all directions, and as it approaches each station
it will uncouple the truck and "motor-omnibus" intended for that
destination. The latter will be shunted on to a loopline. The
road-motor will be set free from its truck and will then proceed on
its journey by road.

When a similar system has been fully adapted for the conveyance of
goods by rail and road experiments will then be commenced, on a
systematic basis, with the object of rendering possible the picking up
of packages, and even of vehicles, without stopping the train. The
most pressing problem which now awaits solution in the railway world
is how to serve roadside stations by express trains. "Through"
passengers demand a rapid service; while the roadside traffic goes
largely to the line that offers the most frequent trains. In the
violent strain and effort to combine these two desiderata the most
successful means yet adopted have been those which rely upon the
destruction of enormous quantities of costly engine-power by means of
quick-acting brakes. The amount of power daily converted into the
mischievous heat of friction by the brakes on some lines of railway
would suffice to work the whole of the traffic several times over; but
the sacrifice has been enforced by the public demand for a train that
shall run fast and shall yet stop as frequently as possible.

Progress in this direction has reached its limit. A brake that shall
conserve, instead of destroying, the power of the train's inertia on
pulling up at a station is urgently required; but the efforts towards
supplying the want have not, so far, proved very successful. Each
carriage or truck must be fitted with an air-pump so arranged that, on
the application of the brake by the engine-driver, it shall drive back
a corresponding amount of air to that which has been liberated from
the reservoir, and the energy thus stored must be rendered available
for re-starting the train. Trials in this direction have been made
through the application of strong springs which are caused to engage
upon the wheels when the brake is applied, and thus are wound up, but
which may then be reversed in position, so that for the starting of
the vehicle the rebound of the spring offers material assistance. It
is obvious, however, that the use of compressed air harmonises better
with the railway system than any plan depending upon springs. The
potential elasticity in an air-reservoir of portable dimensions is
enormously greater than that of any metallic spring which could
conveniently be carried.

In picking up and setting down mail-bags a system has been for some
years in operation on certain railway lines indicating in a small way
the possibilities of the future in the direction of obviating the need
for stopping trains at stations. The bag is hung on a sliding rod
outside of the platform, and on a corresponding part of the van is
affixed a strong net, which comes in contact with the bag and catches
it while the train goes past at full speed. Dropping a bag is, of
course, a simpler matter.

The occasionally urgent demand for the sending of parcels in a similar
manner has set many inventive brains to work on the problem of
extending the possibilities of this system, and there seems no reason
to doubt that before long it will be practicable to load some classes
of small, and not readily broken, articles into trucks or vans while
trains are in motion.

The root idea from which such an invention will spring may be borrowed
from the sliding rail and tobogganing devices already introduced in
pleasure grounds for the amusement of those who enjoy trying every
novel excitement. A light and very small truck may be caused to run
down an incline and to throw itself into one of the trucks comprising
a goods train. The method of timing the descent, of course, will only
be definitely ascertained after careful calculation and experiments
designed to determine what length of time must elapse between the
liberation of the small descending truck and the passing of the
vehicle into which its contents are to be projected.

Foot-bridges over railway lines at wayside stations will afford the
first conveniences to serve as tentative appliances for the purpose
indicated. From the overway of the bridge are built out two light
frameworks carrying small tram-lines which are set at sharp
declivities in the directions of the up and the down trains
respectively, and which terminate at a point just high enough to clear
the smoke-stack of the engine.

The small truck, into which the goods to be loaded are stowed with
suitable packings to prevent undue concussion, is held at the top of
its course by a catch, readily released by pressure on a lever from
below. The guard's van is provided at its front end with a steel,
upright rod carrying a cross-piece, which is easily elevated by the
guard or his assistant in anticipation of passing any station where
parcels are to be received by projection. At the rear of the van is an
open receptacle communicating by a door or window with the van itself.
At the instant when the steel cross-piece comes in contact with the
lever of the catch, which holds the little truck in position on the
elevated footbridge, the descent begins, and by the time that the
receptacle behind the van has come directly under the end of the
sloping track the truck has reached the latter point and is brought to
a sudden standstill by buffers at the termination of the miniature
"toboggan". The ends of the little truck being left open, its contents
are discharged into the receptacle behind the van, from which the
guard or assistant in charge removes them into the vehicle itself. For
catching the parcels thrown out from the van a much simpler set of
apparatus is sufficient.

On a larger scale, no doubt in course of time, a somewhat similar plan
will be brought into operation for causing loaded trucks to run from
elevated sidings and to join themselves on to trains in motion. One
essential condition for the attainment of this object is that the
rails of the siding should be set at such a steep declivity that, when
the last van of the passing train has cleared the points and set the
waiting truck in motion by liberating its catch, the rate of speed
attained by the pursuing vehicle should be sufficiently high to enable
it to catch the train by its own impetus.

It may be found more convenient on some lines to provide nearly level
sidings and to impart the necessary momentum to the waiting truck,
partly through the propelling agency of compressed air. Any project
for what will be described as "shooting a truck loaded with valuable
goods after the retreating end of a train," in order to cause it to
catch up with the moving vehicles, will no doubt give rise to alarm;
and this feeling will be intensified when further proposals for
projecting carriages full of passengers in a similar method come up
for discussion. But these apprehensions will be met and answered in
the light of the fact that in the earlier part of the nineteenth
century critics of what was called "Stephenson's mad scheme" of making
trains run twenty or even thirty miles an hour were gradually induced
to calm their nerves sufficiently to try the new experience of a train
journey!

The wire-rope tramway has hitherto been used principally in connection
with mines situated in very hilly localities. Trestles are erected at
intervals upon which a strong steel rope is stretched and this carries
the buckets or trucks slung on pulley-blocks, contrived so as to pass
the supports without interference. A system of this kind can be worked
electrically, the wire-rope being employed also for the conveyance of
the current. But an inherent defect in the principle lies in the fact
that the wire-rope dips deeply when the weight passes over it, and
thus the progress from one support to another resolves itself into a
series of sharp descents, followed by equally sharp ascents up a
corresponding incline. The usual way of working the traffic is to haul
the freight by means of a rope wound round a windlass driven by a
stationary engine at the end. The constantly varying strain on the
cable proves how large is the amount of power that must be wasted in
jerking the buckets up one incline to let them jolt down another when
the point of support has been passed.

Hitherto the wire-rope tramway has been usually adopted merely as
presenting the lesser of two evils. If the nature of the hills to be
traversed be so precipitous that ruinous cuttings and bridges would be
needed for the construction of an ordinary railway or tramway line,
the idea of conveyance by wire suggests itself as being, at least, a
temporary mode of getting over the difficulty. But a great extension
of the principle of overhead haulage may be expected as soon as the
dipping of the load has been obviated, and the portion of the moving
line upon which it is situated has been made rigid. A strong but light
steel framework, placed in the line of the drawing-cable, and of
sufficient length to reach across two of the intervals between the
supports, may be drawn over enlarged pulleys and remain quite rigid
all the time.

The weight-carrying wire-rope is thus dispensed with, and the
installation acquires a new character, becoming, in point of fact, a
moving bridge which is drawn across its supports and fits into the
grooves in the wheels surmounting the latter. The carriage or truck
may be constructed on the plan adopted for the building of the longest
type of modern bogie carriages for ordinary railways, the tensile
strength of steel rods being largely utilised for imparting rigidity.
We now find that instead of a railway we have the idea of what may be
more appropriately called a "wheelway". The primitive application of
the same principle is to be seen in the devices used in dockyards and
workshops for moving heavy weights along the ground by skidding them
on rollers. Practically the main precaution observed in carrying out
this operation is the taking care that no two rollers are put so far
apart that the centre of gravity of the object to be conveyed shall
have passed over one before the end has come in contact with the next
just ahead of it.

The "wheelway" itself will be economical in proportion as the length
of the rigid carriage or truck which runs upon it is increased. The
carrying of cheap freight will be the special province of the
apparatus, and it will therefore be an object to secure the form of
truck which will give, with the least expense, the greatest degree of
rigidity over the longest stretch of span from one support to another.
Some modification of the tubular principle will probably supply the
most promising form for the purpose. The hope of this will be greatly
enhanced through the recent advances in the art of tube-constructing
by which wrought-iron and tough steel tubes can be made quite seamless
and jointless, being practically forged at one operation in the
required tubular shape.

For mining and other similar purposes, the long tubal "wheelway"
trucks of this description can be drawn up an incline at the loading
station so as to be partially "up-ended" in position for receiving the
charges or loads of mineral or other freight. After this they can be
despatched along the "wheelway" on the closing of the door at the
loading end. In regard to the mode of application of the power in
traction, the shorter-distance lines may serve their objects well
enough by adopting the endless wire-rope system at present used on
many mining properties.

But it is found in practice that for heavy freight this endless cable
traction does not suit over distances of more than about two miles.
Mining men insist upon the caution that where this length of distance
has to be exceeded in the haulage of ore from the mine over wire-rope
tramways, there is need for two installations, the loaded trucks being
passed along from one to the other by means of suitable appliances at
the termini.

Electric traction must, in the near future, displace such a cumbrous
system, and the plan upon which it will be applied will probably
depend upon the use of a steel cable along which the motor-truck must
haul itself in its progress. This cable will be kept stationary, but
gripped by the wheels and other appliances of the electric motors with
which the long trucks are provided. Besides this there must also be
the conducting cables for the conveyance of the electric current.

For cheap means of transport in sparsely-developed country, as well as
in regions of an exceptionally hilly contour, the "wheelway" has a
great future before it. Ultimately the system can be worked out so as
to present an almost exact converse of the railway. The rails are
fixed on the lower part of the elongated truck, one on each side;
while the wheels, placed at intervals upon suitable supports,
constitute the permanent way. The amount of constructional work
required for each mile of track under this plan is a mere fraction of
that which is needed for the permanent way and rolling stock of a
railway, the almost entire absence of earth-works being, of course, a
most important source of economy.

Probably the development of transport on the principles indicated by
the evolution of the ropeway or wire-rope tramway will take place
primarily in connection with mining properties, and for general
transport purposes in country of a nature which renders it unsuitable
for railway construction. This applies not merely to hilly regions,
but particularly to those long stretches of sandy country which impede
the transport of traffic in many rich mining regions, and in patches
separating good country from the seaboard. In the "wheelway" for land
of this character the wheels need not be elevated more than a very few
feet above the ground, just enough to keep them clear of the drift
sand which in some places is fatal to the carrying out of any ordinary
railway project.

The conception of a truck or other vehicle that shall practically
carry its own rail-road has been an attractive one to some inventive
minds. In sandy regions, and in other places where a railway track is
difficult to maintain, and where, at any rate, there would hardly be
sufficient traffic to encourage expenditure in laying an iron road, a
very great boon would be a kind of motor which would lay its own rails
in front of its wheels and pick them up again as soon as they had
passed.

A carriage of this kind was worked for some time on the Landes in
France. The track was virtually a kind of endless band which ran round
the four wheels, bearing a close resemblance to the ramp upon which
the horse is made to tread in the "box" type of horse-gear. Several
somewhat similar devices have been brought out, and a gradual approach
seems to have been made towards a serviceable vehicle.

A large wheel offers less resistance to the traction of the weight
upon it than a small one. The principal reason for this is that its
outer periphery, being at any particular point comparatively straight,
does not dip down into every hollow of the road, but strikes an
average of the depressions and prominences which it meets. The
pneumatic tyre accomplishes the same object, although in a different
way, the weight being supported by an elastic surface which fits into
the contour of the ground beneath it; and the downward pressure being
balanced by the sum total of all the resistant forces offered by every
part of the tyre which touches the ground, whether resting on hollows
or on prominences.

Careful tests which have been made with pneumatic-tyred vehicles by
means of various types of dynamometer have proved that, altogether
apart from the question of comfort arising from absence of vibration,
there is a very true and real saving of actual power in the driving of
a vehicle on wheels fitted with inflated tubes, as compared with the
quantity that is required to propel the same vehicle when resting on
wheels having hard unyielding rims. So far as cycles and motor-cars
are concerned, this is the best solution of the problem of averaging
the inequalities of a road that has yet been presented; but when we
come to consider the making of provision for goods traffic carried by
traction engines along ordinary roadways, the difficulties which
present themselves militating against the adoption of the pneumatic
principle--at any rate so long as a cheap substitute for india-rubber
is undiscovered--are practically insurmountable.

Large cart wheels of the ordinary type are much more difficult to
construct than small ones, besides being more liable to get out of
order. The advantages of a large over a small wheel in reducing the
amount of resistance offered by rough roads have long been
recognised, and the limit of height was soon attained. In looking for
improvement in this direction, therefore, we must inquire what new
types of wheel may be suggested, and whether an intermediate plan
between the endless band, as already referred to, and the
old-fashioned large wheel may not find a useful place.

Let the wheel consist of a very small truck-wheel running on the
inside of a large, rigid steel hoop. The latter must be supported, to
keep it from falling to either side, by means of a steel semi-circular
framework rising from the sides of the vehicle and carrying small
wheels to prevent friction. We now have a kind of rail which conforms
to the condition already mentioned, namely, that of being capable of
being laid down in front of the wheel of the truck or vehicle, and of
being picked up again when the weight has passed over any particular
part. The hoop, in fact, constitutes a rolling railway, and the larger
it can with convenience be made, the nearer is the approach which it
presents to a straight railway track as regards the absence of
resistance to the passing of a loaded truck-wheel over it.

The method of applying the rolling hoop, more particularly as regards
the question whether two or four shall be used for a vehicle, will
depend upon the special work to be performed. Some vehicles, however,
will have only two hoops, one on each side, but several small
truck-wheels running on the inside of each. A vehicle of this pattern
is not to be classed with a two-wheeled buggy, because it will
maintain its equilibrium without being held in position by shafts or
other similar means. So far as contact with the road is concerned it
is two-wheeled; and yet, in its relation to the force of gravitation
upon which its statical stability depends, it is a four or six-wheeler
according to the number of the small truck-wheels with which it is
fitted.

Traction engines carrying hoops twenty feet in height, or at any rate
as high as may be found compatible with stability when referred to the
available width on the road, will be capable of transporting goods at
a cost much below that of horse traction. The limit of available
height may be increased by the bringing of the two hoops closer to
each other at the top than they are at the roadway, because the
application of the principle does not demand that the hoops should
stand absolutely erect.

Similar means will, no doubt, be tried for the achievement of a
modified form of what has been dreamt of by cyclists under the name of
a unicycle. This machine will resemble a bicycle running on the inner
rim of a hoop, and will probably attain to a higher speed for show
purposes than the safety high-geared bicycle of the usual pattern. But
it is in the development of goods traffic along ordinary roads that
the hoop-rail principle will make its most noticeable progress. By its
agency not only will the transport of goods along well-made roads
become less costly and more expeditious, but localities in sparsely
settled countries--such as those beyond the Missouri in America and
the interior regions of South Africa, Australia and China--will become
much more readily accessible.

A traction-engine and automobile which can run across broad, almost
trackless plains at the rate of fifteen miles an hour will bring
within quick reach of civilisation many localities in which at
present, for lack of such communication, rough men are apt to grow
into semi-savages, while those who retain the instincts of
civilisation look upon their exile as a living death. It will do more
to enlighten the dark places of the earth than any other mechanical
agency of the twentieth century.




                              CHAPTER VI.

                                SHIPS.


The "cargo slave" and the "ocean greyhound" are already differentiated
by marked characteristics, and in the twentieth century the divergence
between the two types of vessels will become much accentuated. The
object aimed at by the owners of cargo boats will be to secure the
greatest possible economy of working, combined with a moderately good
rate of speed, such as may ensure shippers against having to stand out
of their capital locked up in the cargo for too long a period. Hence
cheap power will become increasingly a desideratum, and the possible
applications of natural sources of energy will be keenly scrutinised
with a view to turning any feasible plan to advantage. The sailing
ship, and the economic and constructive lines upon which it is built
and worked, will be carefully overhauled with a view to finding how
its deficiencies may be supplemented and its good points turned to
account. One result of this renewed attention will be to confirm, for
some little time, the movement which showed itself during the past
decade of the nineteenth century for an increase of sailing tonnage.
Sooner or later, however, it will be recognised that sail power must
be largely supplemented, even on the "sailer," if it is to hold its
own against steam.

For mails and passengers, on the other hand, steam must more and more
decidedly assert its supremacy. Yet the mail-packet of the twentieth
century will be very different from packets which have "made the
running" towards the close of the nineteenth. She will carry little or
no cargo excepting specie, and goods of exceptionally high value in
proportion to their weight and bulk. Nearly all her below-deck
capacity, indeed, will be filled with machinery and fuel. She will be
in other respects more like a floating hotel than the old ideal of a
ship, her cellars, so to speak, being crammed with coal and her upper
stories fitted luxuriously for sitting and bed rooms and brilliant
with the electric light. But in size she will not necessarily be any
larger than the nineteenth century type of mail steamer. Indeed the
probability is that, on the average, the twentieth century
mail-packets will be smaller, being built for speed rather than for
magnificence or carrying capacity.

The turbine-engine will be the main factor in working the approaching
revolution in mail steamer construction. The special reason for this
will consist in the fact that only by its adoption can the conditions
mentioned above be fulfilled. With the ordinary reciprocating type of
marine steam machinery it would be impossible to place, in a steamer
of moderate tonnage, engines of a size suitable to enable it to attain
a very high rate of speed, because the strain and vibration of the
gigantic steel arms, pulling and pushing the huge cranks to turn the
shafting, would knock the hull to pieces in a very short time. For
this very reason, in fact, the marine architect and engineer have
hitherto urged, with considerable force of argument, that high speed
and large tonnage must go concomitantly. Practically, only a big
steamer, with the old type of marine-engine, could be a very fast one,
and, for ocean traffic at any rate, a smaller vessel must be regarded
as out of the running. Very large tonnage being thus made a prime
necessity, it followed that the space provided must be utilised, and
this need has tended to perpetuate the combination of mail and
passenger traffic with cargo carrying.

The first step towards the revolution was taken many years ago when
the screw propeller was substituted for the paddle-wheel. The latter
means of propulsion caused shock and vibration not only owing to the
thrusts of the piston-rod from the steam-engine itself, but also from
the impact of the paddles upon the water one after the other. A great
increase in the smoothness of running was attained when the screw was
invented--a propeller which was entirely sunk in the water and
therefore exercised its force, not in shocks, but in gentle constant
pressure upon the fluid around it. Such as the windmill is for wind
and the turbine water-wheel for water was the screw propeller,
although adapted, not as a generator, but as an application of power.
Having made the work and stress continuous, the next thing to be
accomplished was to effect a similar reform in the engines supplying
the power. This is accomplished in the turbine steam-engine by causing
the steam to play in strong jets continuously and steadily upon vanes
which form virtually a number of small windmills. Thus, while the
screw outside of the hull is applying the force continuously, the
steam in the inside is driving the shafting with equal evenness and
regularity.

The steam turbine does not appear to have by any means reached
finality in its form, such questions as the angle of impact which the
jet should make with the surface of the vane, and the size of the
orifice through which the steam should be ejected, being still
debatable points. But on one matter there is hardly any room for
doubt, and that is that the best way to secure the benefit of the
expansive power of steam is to permit it to escape from a pipe having
a long series of orifices and to impinge upon a correspondingly
numerous series of vanes, or, perhaps, upon a number of vanes arranged
so that each one is long enough to receive the impact of many jets.

Hitherto the steam supply-pipe emitting the jet has been placed
outside of the circle of the wheel; but the future form seems likely
to be one in which the axis of the wheel is itself the pipe which
contains the steam, but which permits it to escape outwards to the
circumference of the wheel. The latter is, in this form of turbine,
made in the shape of a paddle-wheel of very small circumference but
considerable length, the paddles being set at such an inclination as
to obtain the greatest possible rotative impulse from the
outward-rushing steam. The pipe must be turned true at intervals to
enable it to carry a number of diminutive wheels upon which these long
vanes are mounted, and a very strong connection must be made between
these wheels and the shaft of the screw. Inasmuch as a high speed of
rotation is to be maintained, the pitch of the screw in the water is
set so as to offer but slight opposition to the water at each turn.
The immense speed attained is thus due, not to the actual power with
which the water is struck by the screw at each revolution, but to the
extraordinary rapidity with which the shaft rotates.

The twin screw, with which the best and safest of modern steam-ships
are all fitted, will soon develop into what may be called "the twin
stern". Each screw requires a separate set of engines and the main
object of the duplication is to lessen the risk of the vessel being
left helpless in case of accident to one or other. The advisability of
placing each engine and shafting in a separate water-tight compartment
has therefore been seen. At this point there presents itself for
consideration the advisability of separating the two screws by as wide
a distance as may be convenient and placing the rudder between the
two. Practically, therefore, it will be found best to build out a
steel framework from each side of the stern for holding the bearings
of each screw in connection with the twin water-tight compartments
holding the shafting; and thus will be evolved what will practically
represent a twin, or double, stern.

In the case of the turbine steamer several of the forms of screw which
were first proposed when that type of propeller was invented will
again come up for examination, notably the Archimedean screw, wound
round a fairly long piece of shafting. The larger the circular area of
this screw is the less will be the risk of "smashing" the water, or of
losing hold of it entirely in rough weather. With twin screws of the
large Archimedean type the propelling apparatus of a turbine steamer
will--if the screws are left open--be objected to on the ground of
liability to foul or to get broken in crowded fairways. Hence will
arise a demand for accommodation for each screw in a tube forming part
of the lower hull itself and open at the side for the taking in of
water, while the stern part is equally free. In this way there is
evolved a kind of compromise between the two principles of marine
propulsion, by a screw and by a jet of water thrown to sternward. The
water-jet is already very successfully employed for the propulsion of
steam lifeboats in which, owing to the danger of fouling the
life-saving and other tackle, an open screw is objectionable.

The final extermination of the sailing ship is popularly expected as
one of the first developments of the twentieth century in maritime
traffic. Steam, which for oversea trade made its entrance cautiously
in the shape of a mere auxiliary to sail power, had taken up a much
more self-assertive position long before the close of the nineteenth
century, and has driven its former ally almost out of the field in
large departments of the shipping industry. Yet a curious and
interesting counter movement is now taking place on the Pacific Coast
of America, as well as among the South Sea Islands and in several
other places where coal is exceptionally dear. Trading schooners and
barques used in these localities are often fitted with petroleum oil
engines, which enable them to continue their voyages during calm or
adverse weather. For the owners of the smaller grade of craft it was a
material point in recommendation of this movement that, having no
boiler or other parts liable to explode and wreck the vessel, an oil
engine may be worked without the attendance of a certificated
engineer. As soon as this legal question was settled a considerable
impetus was given to the extension of the auxiliary principle for
sailing ships. The shorter duration of the average voyage made by the
sail-and-oil power vessels had the effect of enabling shippers to
realise upon the goods carried more speedily than would have been
possible under the old system of sail-power alone.

It is already found that in the matter of economy of working,
including interest on cost of vessel and cargo, these oil-auxiliary
ships can well hold their own against the ordinary steam cargo slave.
Up to a certain point, the policy of relying upon steam entirely,
unaided by any natural cheap source of power, has been successful; but
the rate of speed which the best types of marine engines impart to
this kind of vessel is strictly limited, owing to considerations of
the enormous increase of fuel-consumption after passing the twelve or
fourteen mile grade. For ocean greyhounds carrying mails and
passengers the prime necessity of high speed has to a large extent
obliterated any such separating line between waste and economy. It is,
however, a mistake to imagine that the cargo steamer of the future
will be in any sense a replica of the mail-boat of to-day. The
opposition presented by the water to the passage of a vessel increases
by leaps and bounds as soon as the rate now adopted by the cargo
steamer is passed, and thus presents a natural barrier beyond which it
will not be economically feasible to advance much further.

If then we recognise clearly that steam cargo transport across the
ocean can only be done remuneratively at about one half the speed now
attained by the very fastest mail-boats, we shall soon perceive also
that the chances of the auxiliary principle, if wisely introduced,
placing the "sailer" on a level with the cargo ship worked by steam
alone, are by no means hopeless. A type of vessel which can be trusted
to make some ten or twelve knots regularly, and which can also take
advantage of the power of the wind whenever it is in its favour, must
inevitably possess a material advantage over the steam cargo slave in
economy of working, while making almost the same average passages as
its rival.

Then, also, the sailless cargo slave, in the keen competition that
must arise, will be fitted with such appliances as human ingenuity can
in future devise, or has already tentatively suggested, for invoking
the aid of natural powers in order to supplement the steam-engine and
effect a saving in fuel. One of these will no doubt be the adoption of
the heavy pendulum with universal joint movement in a special hold of
the vessel so connected with an air-compression plant that its
movements may continually work to fill a reservoir of air at a high
pressure. The marine engines of the ordinary type will then be
adapted to work with compressed air, and the true steam-engine itself
will be used for operating an air compressor on the system adopted in
mines.

The pendulum apparatus, of course, is really a device for enabling a
vessel to derive, from the power of the waves which raise her and roll
her, an impetus in the desired direction of her course. Inventions of
this description will at first be only very cautiously and partially
adopted, because if there is one thing which the master mariner fears
more than another it is any heavy moving weight in the hold, the
motions of which during a storm might possibly become uncontrollable.
When steam was first applied to the propulsion of ships the common
argument against it was that any machine worked by steam and having
sufficient power to propel a vessel would also develop so much
vibration as to pull her to pieces--to say nothing of the risk of
having her hull shattered at one fell blow by the explosion of the
steam boiler. These undoubtedly are dangers which have to be provided
against, and probably the occasional lack of care has been the cause
of many an unreported loss, as well as of recorded mishaps from broken
tail-shafts and screws, or from explosions far out at sea.

The air-compressing pendulum will no doubt be constructed on such a
principle that, whenever there is any danger of its weighty movements
getting beyond control or doing any damage to the vessel, its force
can be instantly removed at will, and the apparatus can be brought to
a standstill by the application of friction brakes and other means.
The weight may be made up of comparatively small pigs of iron, which,
through the opening of a valve controlled from the deck by the stem of
the pendulum, can be let fall out into the hold separately. The
swinging framework would then be steadied by the friction brake
gripping it gradually.

Auxiliary machinery of this class can only be made use of, as already
indicated, to a certain strictly limited extent, owing to the tendency
of any swinging weight in a vessel to aggravate the rolling during
heavy weather. Some tentative schemes have been put forward for
tapping a source of wave-power by providing a vessel with flippers,
resting upon the surface of the water outside her hull, and actuating
suitable internal machinery with the object of propulsion. A certain
amount of encouragement has been given by the performances of small
craft fitted in this way; but it is objected by sea-faring men that
the behaviour of a large vessel, encumbered with outlying parts
moving on the waves independently, would probably be very erratic
during a storm and would endanger the safety of the ship itself. No
kind of floating appendage, moving independently of the vessel, could
exercise any actual force by the uprising of a wave in lifting it
without being to some extent sunk in the water; and, accordingly, when
the waves were running high there would be imminent risk that heavy
volumes of water would get upon the apparatus and prevent the ship
from righting itself. Many of the schemes that have been put forward,
by patent and otherwise, for the automatic propulsion of ships have
entirely failed to commend themselves by reason of their taking little
or no account of the behaviour of a ship, fitted with the proposed
inventions, during very rough and trying weather.

The swinging pendulum, with connected apparatus for compressing air
or, perhaps, for generating the electric current, seems to be the most
controllable and therefore the safest of the various types of
apparatus which are applicable to the utilisation of wave-power for
propulsion. In the construction of connecting machinery by which the
movements of a pendulum hanging up from a universal joint may be
transmitted to wheels or pistons operating compressors or dynamos, it
is necessary to transform all motions passing in any direction
through the spherical or bowl-shaped figure traced out by the end of
the pendulum in the course of its swinging. This may be effected, for
instance, in the case of a pendulum working air-compressors, by
mounting the latter on bearings like those of the gun-carriage in a
field piece, and having two of them operating one at right angles to
the other. The rods which carry the air-compressing pistons are then
connected to the end of the pendulum by universal joints, and the
parts which have been likened to a gun-carriage are fixed on pivots so
as to be able to move horizontally. Air-tight joints in the pipes
which lead to the compressed air reservoir are placed in the bearings
of this mounting. We thus have the same kind of provision for taking
advantage of a universal movement in space as is made in solid
geometry by three co-ordinates at right angles to one another for
measuring such movements.

Another plan is to have the pendulum swung in a strong steel collar
and carrying at its end three or more air-compressing pumps set
radially, with the piston-rods thrust outwards by a strong spring on
each, but with the ends perfectly free from any attachment, yet fitted
with a buffer or wheel. As the pendulum moves it throws one or more
of these piston-rod ends into contact with the inner surface of the
ring, driving it into the compressing pump. At the top of the pendulum
there is a double or universal pipe-joint through which the air under
pressure is driven to the reservoir, and by which the apparatus is
also hung. This is the simplest, and in some respects the best, form.

A very simple type of the wave-power motor as applied to marine
propulsion is based upon an idea taken from the mode of progression
adopted by certain crustaceans, namely the possession of the means for
drawing in and rapidly ejecting the water. Something of the kind will
most probably be made available for assisting in the propulsion of
sailing ships which are not furnished with machinery of any type
suitable for the driving of a screw. A very much simplified form of
the pendulous or rocking weight is applicable in this case. A
considerable amount of cargo is stowed away in an inner hull, taking
the shape of what is practically a gigantic cradle rocking upon
semicircular lines of railway iron laid down in the form of ribs of
the ship. To the sides of these large rocking receptacles are
connected the rods carrying, at their other ends, the pistons of large
force-pumps which draw the water in at one stroke and force it out to
sternwards, below the water line, at the other.

In this arrangement it is obvious that only the "roll" and not the
"pitch" of the vessel can be utilised as the medium through which to
obtain propulsive force. But it is probable that fully eighty per
cent. of the movements of a vessel during a long voyage--as indicated,
say, by the direction and sweep of its mast-heads--consists of the
roll. Each ton of goods moved through a vertical distance of one foot
in relation to the hull of the vessel, has in it the potentiality of
developing, when fourteen or fifteen movements occur per minute, about
one horse-power. A cradle containing 200 tons, as may therefore be
imagined, can be made to afford very material assistance in helping
forward a sailing ship during a calm. In such tantalising weather the
"ground-swell" of the ocean usually carries past a becalmed vessel
more waste energy than is ever utilised by its sails in the briskest
and most propitious breeze.

For sailing ships especially, the rocking form of wave-motor as an aid
to propulsion will be recommended on account of the fact that when the
weather is "on the beam" both of its sources of power can be kept in
full use. The sailing vessel must tack at any rate with the object of
giving its sail power a fair chance, and thus, when it has not a fair
"wind that follows free," it must always seek to get the breeze on its
beam, and therefore usually the swell must be taking it sideways. It
would be only on rare occasions that a sailing vessel, if furnished
with rocking gear for using the wave-power, would be set to go nearer
to the teeth of the wind than she would under present conditions of
using sail-power alone. The advantage of the wave-power, however,
would be seen mainly during the calm and desultory weather which has
virtually been the means of forcing sail-power to resign its supremacy
to steam.

For checking the rocker in time of heavy weather special appliances
are necessary, which, of course, must be easily operated from the
deck. Wedge-shaped pieces with rails attached may be driven down by
screws upon the sides of the vessel, thus having the effect of
gradually narrowing the amplitude of the rocking motion until a
condition of stability with reference to the hull has been attained.

In the building of steel ships, as well as in the construction of
bridges and other erections demanding much metal-work, great economies
will be introduced by the reduction of the extent to which riveting
will be required when the full advantages of hydraulic pressure are
realised. The plates used in the building of a ship will be
"knocked-up" at one side and split at the other, with the object of
making joints without the need for using rivets to anything like the
extent at present required. In putting the plates thus treated
together to form the hull of a vessel the swollen side of one plate is
inserted between the split portions of another and the latter parts
are then clamped down by heavy hydraulic pressure. This important
principle is already successfully used in the making of rivetless
pipes, and its application to ships and bridges will be only a matter
of a comparatively short time. Through this reform, and the further
use of steel ribs for imparting strength and thus admitting of the
employment of thinner steel plates for the actual shell, the cost of
shipbuilding will be very greatly reduced.

Hoisting and unloading machines will play a notable part in minimising
the expenses of handling goods carried by sea. The grain-elevator
system is only the beginning of a revolution in this department which
will not end until the loading and unloading of ships have become
almost entirely the work of machinery. The principle of the miner's
tool known as the "sand-auger" may prove itself very useful in this
connection. From a heap of tailings the miner can select a sample, by
boring into it with a thin tube, inside of which revolves a shaft
carrying at its end a flat steel rotary scoop. The auger, after
working its way to the bottom of the heap, is raised, and, of course,
it contains a fair sample of the sand at all depths from the top
downwards. On a somewhat similar principle the unloading of ships
laden with grain, ore, coal, and all other articles which can be
handled in bulk and divided, will be carried out by machines which, by
rotary action, will work their way down to the bottom of the hull and
will then be elevated by powerful lifting cranes. For other classes of
goods permanent packages and tramways will be provided in each ship,
and trucks will be supplied at the wharf.

For coastal passages across shallow but rough water like the English
Channel, the services of moving bridges will be called into
requisition. One of these has been at work at St. Malo on the French
coast opposite Jersey, and another was more recently constructed on
the English coast near Brighton. For the longer and much more
important service across the Channel submarine rails may be laid down
as in the cases mentioned, but in addition it will be necessary to
provide for static stability by fixing a flounder-shaped pontoon just
below the greatest depth of wave disturbance, and just sufficient in
buoyancy to take the great bulk of the weight of the structure off the
rails. In this way passengers may be conveyed across straits like the
Channel without the discomforts of sea-sickness.

The stoking difficulties on large ocean-going steamers have become so
acute that they now suggest the conclusion that, notwithstanding
repeated failures, a really effective mechanical stoker will be so
imperatively called for as to enforce the adoption of any reasonably
good device. The heat, grime, and general misery of the stoke-hole
have become so deterrent that the difficulty of securing men to
undertake the work grows greater year by year, and in recruiting the
ranks of the stokers resort had to be had more and more to those
unfortunate men whose principal motive for labour is the insatiable
desire for a drinking bout. On the occasions of several shipwrecks in
the latter part of the nineteenth century disquieting revelations took
place showing how savagely bitter was the feeling of the stoke-hole
towards the first saloon. As soon as the mechanical fuel-shifter has
been adopted, and the boilers have been properly insulated in order to
prevent the overheating of the stoke-hole, the stoker will be raised
to the rank of a secondary engineer, and his work will cease to be
looked upon as in any sense degrading.

On the cargo-slave steamer and sailer a similar social revolution will
be brought about by the amelioration of the conditions under which the
men live and work. Already some owners and masters have begun to
mitigate, to a certain extent, the embargo which the choice of a
sea-faring life has in times past been understood to place upon
married men. Positions are found for women as stewardesses and in
other capacities, and it is coming to be increasingly recognised that
there is a large amount of women's work to be done on board a ship.

By and by, when it is found that the best and steadiest men can be
secured by making some little concessions to their desire for a
settled life and their objections to the crimp and the "girl at every
port," and all the other squalid accessories so generally attached in
the popular mind to the seaman's career, there will be a serious
effort on the part of owners to remodel the community on board of a
ship on the lines of a village. There will be the "Ship's Shop" and
the "Ship's School," the "Ship's Church" and various other
institutions and societies.

Thus in the twentieth century the sea will no longer be regarded, to
the same extent as in the past, as the refuge for the ne'er-do-well of
the land-living populace; and this, more than perhaps anything else,
will help to render travelling by the great ocean highways safe and
comfortable. It is a common complaint on the part of owners that by
far the larger part of maritime disasters are directly traceable to
misconduct or neglect of duty on the part of masters, officers or
crew; but they have the remedy in their own hands.




                             CHAPTER VII.

                             AGRICULTURE.


Muscular power still carries out all the most laborious work of the
farm and of the garden--work which, of course, consists, in the main,
of turning the land over and breaking up the sods. In the operations
of ploughing, harrowing, rolling, and so forth, the agency almost
exclusively employed is the muscular power of the horse guided by
man-power; with the accompaniment of a very large and exhausting
expenditure of muscular effort on the part of the farmer or farm
labourer. On the fruit and vegetable garden the great preponderance of
the power usefully exercised must, under existing conditions, come
direct from the muscles of men. Spade and plough represent the badges
of the rural workers' servitude, and to rescue the country residents
from this old-world bondage must be one of the chief objects to which
invention will in the near future apply itself.

The miner has to a very large extent escaped from the thraldom of mere
brute-work, or hardening muscular effort. He drills the holes in the
face of the rock at which he is working by means of compressed air or
power conveyed by the electric current; and then he performs the work
of breaking it down by the agency of dynamite or some other high
explosive. Much heavy bodily labour, no doubt, remains to be done by
some classes of workers in mines; but the significance of the march of
improvement is shown by the fact that a larger and larger proportion
of those who work under the surface of the ground, or in ore-reduction
works, consists of men who are gradually being enrolled among the
ranks of the more highly skilled and intelligent workers, whose duty
it is to understand and to superintend pieces of mechanism driven by
mechanical power.

In farming and horticulture the field of labour is not so narrowly
localised as it is in mining. Work representing an expenditure of
hundreds of thousands of pounds may be carried out in mines whose area
does not exceed two or three acres; and it is therefore highly
renumerative to concentrate mechanical power upon such enterprises in
the most up-to-date machinery. But the farmer ranges from side to side
of his wide fields, covering hundreds, or even thousands, of acres
with his operations. He is better situated than the miner in respect
of the economical and healthy application of horse-power, but far
worse in regard to the immediate possibilities of steam-power and
electrically-conducted energy. No one can feed draught stock more
cheaply than he, and no one can secure able-bodied men to work from
sunrise till evening at a lower wage.

Yet the course of industrial evolution, which has made so much
progress in the mine and the factory, must very soon powerfully affect
agriculture. Already, in farming districts contiguous to unlimited
supplies of cheap power from waterfalls, schemes have been set on foot
for the supply of power on co-operative principles to the farmers of
fertile land in America, Germany, France, and Great Britain. One
necessity which will most materially aid in spurring forward the
movement for the distribution of power for rural work is the
requirement of special means for lifting water for irrigation, more
particularly in those places where good land lies very close to the
area that is naturally irrigable, by some scheme already in operation
but just a little too high. Here it is seen at once that power means
fertility and consequent wealth, while the lack of it--if the climate
be really dry, as in the Pacific States of America--means loss and
dearth. But the presence of a source of power which can easily be
shifted about from place to place on the farm for the purpose of
watering the ground must very soon suggest the applicability of the
same mechanical energy to the digging or ploughing of the soil.

It is from this direction, rather than from the wide introduction of
steam-ploughs and diggers, that the first great impetus to the
employment of mechanical power on the farm may be looked for. The
steam-plough, no doubt, has before it a future full of usefulness; and
yet the slow progress that has been made by it during a quarter of a
century suggests that, in its present form--that is to say while built
on lines imitating the locomotive and the traction-engine--it cannot
very successfully challenge the plough drawn by horse-power. More
probable is it--as has already been indicated--that the analogy of the
rock-drill in mining work will be followed. The farmer will use an
implement much smaller and handier than a movable steam-engine, but
supplied with power from a central station, either on his own land or
in some place maintained by co-operative or public agency. Just as the
miner pounds away at the rock by means of compressed air or
electricity, brought to his hands through a pipe or a wire, so the
farmer will work his land by spades or ploughs by the same kind of
mechanical power. The advantages of electrical transmission of energy
will greatly favour this kind of installation on the farm, as compared
with any other method of distribution which is as yet in sight.

For the ploughing of a field by the electric plough a cable will be
required capable of being stretched along one side of the area to be
worked. On this will run loosely a link or wheel connected with
another wire wound upon a drum carried on the plough and paid out as
the latter proceeds across the field. For different grades of land, of
course, different modes of working are advisable, the ordinary plough
of a multifurrow pattern, with stump-jumping springs or weights, being
used for land which is not too heavy or clayey; a disc plough or
harrow being applicable to light, well-worked ground; and the
mechanical spade or fork-digger--reciprocating in its motion very much
like the rock-drill--having its special sphere of usefulness in wet
and heavy land. In any case a wide, gripping wheel is required in
front to carry the machine forward and to turn it on reaching the end
of the furrow. The wire-wound drum is actuated by a spring which tends
to keep it constantly wound up, and when the plough has turned and is
heading again towards the cable at the side of the field, this drum
automatically winds up the wire. So also when each pair of furrows has
been completed, the supply-wire is automatically shifted along upon
the fixed cable to a position suitable for the next pair.

Not only in the working, but also in the manuring, of the soil the
electric current will play an important part in the revolution in
agriculture. The fixing of the nitrogen from the atmosphere in order
to form nitrates available as manure depends, from the physical point
of view, upon the creation of a sufficient heat to set fire to it. The
economic bearings of this fact upon the future of agriculture,
especially in its relation to wheat-growing, seemed so important to
Sir William Crookes that he made the subject the principal topic of
his Presidential Address before the British Association in 1898.

The feasibility of the electrical mode of fixing atmospheric nitrogen
for plant-food has been demonstrated by eminent electricians, the
famous Hungarian inventor, Nikola Tesla, being among the foremost. The
electric furnace is just as readily applicable for forcing the
combination of an intractable element, such as nitrogen, with other
materials suitable for forming a manurial base, as it is for making
calcium carbide by bringing about the union of two such unsociable
constituents as lime and carbon.

Cheap power is, in this view, the great essential for economically
enriching the soil, as well as for turning it over and preparing it
for the reception of seed. Nor is the fact a matter of slight
importance that this power is specially demanded for the production of
an electric current for heating purposes, because the transmission of
such a current over long distances to the places at which the manurial
product is required will save the cost of much transport of heavy
material.

The agricultural chemist and the microbiologist of the latter end of
the nineteenth century have laid considerable stress upon the
prospects of using the minute organisms which attach themselves to the
roots of some plants--particularly those of the leguminaceæ--as the
means of fixing the nitrogen of the atmosphere, and rendering it
available for the plant-food of cereals which are not endowed with the
faculty of encouraging those bacteria which fix nitrogen. High hopes
have been based upon the prospects of inoculating the soil over wide
areas of land with small quantities of sandy loam, taken from patches
cultivated for leguminous plants which have been permitted to run to
seed, thus multiplying the nitrogen-fixing bacteria enormously. The
main idea has been to encourage the rapid production of these minute
organisms in places where they may be specially useful, but in which
they do not find a particularly congenial breeding ground.

The hope that any striking revolution may be brought about in the
practice of agriculture by a device of this kind must be viewed in the
light of the fact that, while the scientists of the nineteenth century
have demonstrated, partially at least, the true reason for the
beneficial effects of growing leguminous plants upon soil intended to
be afterwards laid down in cereals, they were not by any means the
first to observe the fact that such benefits accrued from the practice
indicated. Several references in the writings of ancient Greek and
Latin poets prove definitely that the good results of a rotation of
crops, regulated by the introduction of leguminous plants at certain
stages, were empirically understood. In that more primitive process of
reasoning which proceeds upon the assumption _post hoc, ergo propter
hoc_, the ancient agriculturist was a past-master, and the chance of
gleaning something valuable from the field of common observation over
which he has trod is not very great.

Modern improvements in agriculture will probably be, in the main, such
as are based upon fundamental processes unknown to the ancients. By
the word "processes" it is intended to indicate not those methods the
scientific reasons for which were understood--for these in ancient
times were very few--but simply those which from long experience were
noticed to be beneficial. Good husbandry was in olden times clearly
understood to include the practice of the rotation of crops, and the
beneficial results to be expected from the introduction of those crops
which are now discovered to act as hosts to the microbes which fix
atmospheric nitrogen were not only observed, but insisted upon.

From a scientific point of view this concurrence of the results of
ancient and of modern observation may only serve to render the
bacteriology of the soil more interesting; but, from the standpoint of
an estimate of the practical openings for agriculture improvements in
the near future, it greatly dwarfs the prospect of any epoch-making
change actually founded upon the principle of the rotation of crops.
It is, indeed, conceivable that fresh light on the life habits of the
minute organisms of the soil may lead to practical results quite new;
but hardly any such light is yet within the inventor's field of
vision.

This view of the limited prospects of practical microbiology for the
fixing of nitrogen in plant-food was corroborated by Sir William
Crookes in the Presidential Address already cited. He said that
"practice has for a very long time been ahead of science in respect of
this department of husbandry". For ages what is known as the four
course rotation had been practised, the crops following one another in
this order--turnips, barley, clover and wheat--a sequence which was
popular more than two thousand years ago. His summing up of the
position was to the effect that "our present knowledge leads to the
conclusion that the much more frequent growth of clover on the same
land, even with successful microbe-seeding and proper mineral
supplies, would be attended with uncertainties and difficulties,
because the land soon becomes what is called clover-sick, and turns
barren".

In regard to any practical application of microbe-seeding, the farmers
of the United Kingdom at the end of the nineteenth century had not, in
the opinion of this eminent chemist, reached even the experimental
stage, although on the Continent there had been some extension of
microbe cultivation. To this it may fairly be added that some of the
attention attracted to the subject on the Continent has been due to
the natural tendency of the German mind to discover fine differences
between things which are not radically distinct. Under the title of
"microbe-cultivation" the long-familiar practice of the rotation of
crops may to some continental enthusiasts seem to be quite an
innovation!

In the electrical manures-factory the operations will be simply an
enlargement of laboratory experiments which have been familiar to the
chemist for many years. Moist air, kept damp by steam, is traversed by
strong electric sparks from an induction coil inside of a bottle or
other liquor-tight receiver, and in a short time it is found that in
the bottom of this receptacle a liquid has accumulated which, on being
tested, proves to be nitric acid. There is also present a small
quantity of ammonia from the atmosphere. Nitrate of ammonia thus
formed would in itself be a manure; but, of course, on the large scale
other nitrates will be formed by mixing the acid with cheap alkalies
which are abundant in nature, soda from common salt, and lime from
limestone.

In this process the excessive heat of the electric discharge really
raises the nitrogen and oxygen of the atmosphere to a point of
temperature at which chemical union is forced; or, in other words, the
nitrogen is compelled to burn and to join in chemical combination with
the oxygen with which formerly it was only in mechanical mixture. When
nitrogen is burning, its flame is not in itself hot enough to ignite
contiguous volumes of the same element;--otherwise indeed our
atmosphere, after a discharge of lightning, would burn itself
out!--but the continuance of an electric discharge forces into
combination just a proportionate quantity of nitrogen. Practically,
therefore, manure in the future will mean electricity, and therefore
power; so that cheap sources of energy are of the greatest importance
to the farmer.

With dynamos driven by steam-engines, the price of
electrically-manufactured nitrate of soda would, according to the
estimate of Sir William Crookes, be £26 per ton, but at Niagara, where
water power is very cheap, not more than £5 per ton. Thus it will be
seen that the cheapness of power due to the presence of the waterfall
makes such a difference in the economic aspects of the problem of the
electrical manufacture of manurial nitrates as to reduce the price to
less than one-fifth! It must be remembered that at the close of the
nineteenth century the electric installation at Niagara is by very
many persons looked upon as being in itself in the nature of an
experiment, but at any rate there seems to be no room for doubt that
the cost of natural power for electrical installations will very soon
be materially reduced. Even at the price quoted, namely £5 per ton,
the cost of nitrate of soda made with electrically combined
atmospheric nitrogen compares very favourably with commercial nitrates
as now imported for agriculture purposes. "Chili nitrate," in fact, is
about fifty per cent. dearer.

When wave-power and other forms of the stored energy of the wind have
been properly harnessed in the service of mankind, the region around
Niagara will only be one of thousands of localities at which
nitrogenous manures can be manufactured electrically at a price far
below the present cost of natural deposits of nitrate of soda. From
the power stations all around the coasts, as well as from those on
waterfalls and windy heights among the mountains, electric cables will
be employed to convey the current for fixing the nitrogen of the air
at places where the manures are most wanted.

The rediscovery of the art of irrigation is one of the distinguishing
features of modern industrial progress in agriculture. Extensive
ruins and other remains in Assyria, Egypt, India, China and Central
America prove beyond question that irrigation played a vastly more
important part in the industrial life of the ancients than it does in
that of modern mankind. This is true in spite of the fact that power
and dominion ultimately fell to the lot of those races which
originally dwelt in colder and more hilly or thickly-wooded regions,
where the instincts of hunting and of warfare were naturally
developed, so that, by degrees, the peoples who understood irrigation
fell under the sway of those who neither needed nor appreciated it. In
the long interval vast forests have been cleared away and the warlike
habits of the northern and mountainous races have been greatly
modified, but manufacturing progress among them has enabled them to
perpetuate the power originally secured by the bow and the spear. The
irrigating races of mankind are now held in fear of the modern weapons
which are the products of the iron and steel industries, just as they
were thousands of years ago terrorised by the inroads of the wild
hunting men from the North.

But the future of agriculture will very largely belong to a class of
men who will combine in themselves the best attributes of the
irrigationist and the man who knows how to use the iron weapon and
the iron implement. As the manufacturing supremacy of the North
becomes more and more assured by reason of the superior healthiness of
a climate encouraging activity of muscle and brain, so the
agricultural prospects of the warmer regions of the earth's surface
will be improved by the comparative immunity of plant and of animal
life from disease in a dry atmosphere. Sheep, cattle and horses thrive
far better in a climate having but a scanty rainfall than in one
having an abundance of wet; and so, also, does the wheat plant when
the limited rains happen to be timed to suit its growth, and the best
kinds of fruit trees when the same conditions prevail.

All this points to an immense recrudescence of irrigation in the near
future. Already the Californians and other Americans of the Pacific
Slope have demonstrated that irrigation is a practice fully as well
suited to the requirements of a thoroughly up-to-date people as it has
been for long ages to those of the "unchanging East". But here again
the question of cheap power obtrudes itself. The Chinese, Hindoos and
Egyptians have long ago passed the stage at which the limited areas
which were irrigable by gravitation, without advanced methods of
engineering, have been occupied; and the lifting of water for the
supplying of their paddy fields has been for thousands of years a
laborious occupation for the poorest and most degraded of the rural
population.

In a system of civilisation in which transport costs so little as it
does in railway and steam-ship freights, the patches of territory
which can be irrigated by water brought by gravitation from the hills
or from the upper reaches of rivers are comparatively easy of access
to a market. This fact retards the advent of the time when colossal
installations for the throwing of water upon the land will be
demanded. When that epoch arrives, as it assuredly will before the
first half of the twentieth century has been nearly past, the pumping
plants devoted to the purposes of irrigation will present as great a
contrast to the lifting appliances of the East as does a fully loaded
freight train or a mammoth steam cargo-slave to a coolie carrier.

At the same time there must inevitably be a great extension of the
useful purposes to which small motors can be applied in irrigation.
Year by year the importance of the sprinkler, not only for ornamental
grounds such as lawns and flower-beds, but also for the vegetable
patch and the fruit garden, becomes more apparent, and efforts are
being made towards the enlargement of the arms of sprinkling
contrivances to such an extent as to enable them to throw a fine
shower of water over a very large area of ground. Sometimes a windmill
is used for pumping river or well-water into high tanks from which it
descends by gravitation into the sprinklers, the latter being operated
by the power of the liquid as it descends. This mode of working is
convenient in many cases; but a more important, because a more widely
applicable, method in the future will be that in which the wind-motor
not only lifts the water, but scatters it around in the same
operation. Long helical-shaped screws, horizontally fixed between
uprights or set on a swivel on a single high tower, can be used for
loading the breeze with a finely divided shower of water and thus
projecting the moisture to very long distances. A windmill of the
ordinary pattern, as used for gardens, may be fitted with a long
perforated pipe, supported by wire guys instead of a vane, a
connection being made by a water-tight swivel-joint between this pipe
and that which carries the liquid from the pump. In this way every
stroke of the machine sends innumerable jets of water out upon the
wind, to be carried far afield.

Gardening properties in comparatively dry climates, fitted with
machines of this description, can be laid out in different zones of
cultivation, determined according to the prevailing directions of the
wind and the consequent distribution of the water supply. Thus if the
wind most frequently blows from the west the plants which require the
most water must be laid out at the eastern side, not too far from the
sprinkler. Facilities for shutting off the supply of spray at will
are, of course, very necessary. The system of watering founded on this
principle depends upon the assumption that if the gardener or the
farmer could always turn on the rain when he has a fairly good wind he
would never lack for seasonable moisture to nourish his crops. This
will be found in practice to apply correctly to the great majority of
food plants. In the dry climates, which are so eminently healthy for
cereals, "the early and the latter rains," as referred to in
Scripture, are both needed, and one of the most important applications
of cheap power will be directed to supplementing the natural supply
either at one end or at the other.

The "tree-doctor" will be a personage of increasing importance in the
rural economy of the twentieth century. He is already well in sight;
but for lack of capital and of a due appreciation of the value of his
services, he occupies as yet but a comparatively subordinate position.
Fruits, which are nature's most elaborately worked-up edible products,
must come more and more into favour as the complement to the seed food
represented by bread. As the demand increases it will be more clearly
seen that an enormous waste of labour is involved in the culture of an
orchard unless its trees are kept in perfect health. At the same time
the law of specialization must operate to set aside the tree-doctor to
his separate duties, just as the physician and the veterinary surgeon
already find their own distinctive spheres of work. The apparatus
required for the thorough eradication of disease in fruit trees will
be too expensive for the average grower to find any advantage in
buying it for use only a few times during the year; but the
tree-doctor, with his gangs of men, will be able to keep his special
appliances at work nearly all the year round.

For the destruction of almost all classes of fruit-pests, the only
really complete method now in sight is the application of a poisonous
gas, such as hydrocyanic acid, which is retained by means of a
gas-proof tent pitched around each tree. No kind of a spray or wash
can penetrate between bark and stem or into the cavities on fruit so
well as a gaseous insecticide which permeates the whole of the air
within the included space. But the gas-tight tent system of fumigation
is as yet only in its infancy, and its growth and development will
greatly help to place the fruit-growing industry on a new basis, and
to bring the best kinds of fruit within the reach of the middle
classes, the artisans, and ultimately even the very poor. Just as
wheaten bread from being a luxury reserved for the rich has become the
staple of food for all grades of society, so fruits which are now
commonly regarded as an indulgence, although a very desirable addition
to the food of the well-to-do, must, in a short time, become
practically a necessity to the great mass of the people generally.

The waste of effort and of wealth involved in planting trees and
assiduously cultivating the soil for the growth of poor crops
decimated by disease is the prime cause of the dearness of fruit. If,
therefore, it be true that the fruit diet is one which is destined to
greatly improve the average health of civilised mankind, it is obvious
that the tree-doctor will act indirectly as the physician for human
ailments. When this fact has been fully realised the public estimation
in which economic entomology and kindred sciences are held will rise
very appreciably, and the capital invested in complete apparatus for
fighting disease in tree life will be enormously increased.

Very long tents, capable of covering not merely one tree each, but of
including continuous rows stretching perhaps from end to end of a
large orchard, will become practically essential for up-to-date
fruit-culture. An elongated tent of this description, covering a row
of trees, may be filled with fumes from a position at the end of the
row, where a generating plant on a trolley may be situated. At the
opposite end another trolley is stationed, and each movable vehicle
carries an upright mast or trestle for the support of the strong cable
which passes along the row over the tops of the trees and is stretched
taut by suitable contrivances. Attached to this cable is a flexible
tube containing a number of apertures and connected at the generating
station with the small furnace or fumigating box from which the
poisonous gases emanate.

Along the ground at each side of the row are stretched two thinner
wires or cables which hold the long tent securely in position. The
method of shifting from one row to another is very simple. Both
trolleys are moved into their new positions at the two ends of a fresh
row, the fastenings of the tent at the ground on the further side
having been released, so that the flap of the tent on that side is
dragged over the tops of the trees and may then be drawn over the top
cable and down upon the other side. Seen from the end, the movements
of the tent thus resemble those of a double-hinged trestle in the form
of an inverted V which advances by having one leg flung over the
other. For this arrangement of a fumigating tent it is best that the
top cable should consist of a double wire, the fabric of the tent
itself being gripped between the two wires, and a flexible tube being
attached to each.

As progress is made from one row to another through the drawing of one
flap over the other, it is obvious that the tent turns inside out at
each step, and if only one cable and one tube were used, it would be
difficult to avoid permitting the gas to escape into the outer air at
one stage or another. But when the tubes are duplicated in the manner
described, there is always one which is actually within the tent no
matter what position the latter may be in. It is then only necessary
that the connection with the generating apparatus at the end of the
row should be made after each movement with the tube which is inside
the tent. For very long rows of trees the top cable needs to be
supported by intermediate trestles besides the uprights at the ends.

The gas and air-proof tent can be used for various other purposes
besides those of killing pests on fruit trees. One of the regular
tasks of the tree-doctor will be connected with the artificial
fertilisation of trees on the wholesale scale and for a purpose such
as this it is necessary that the trees to be operated upon shall not
be open to the outside atmosphere, but that the pollen dust, with
which the air inside the tent is to be laden, shall be strictly
confined during a stated period of time. Those methods of
fertilisation, with which the flower-gardener has in recent years
worked such wonders, can undoubtedly be utilised for many objects
besides those of the variation of form and hue in ornamental plants.




                            CHAPTER VIII.

                               MINING.


Exploratory telegraphy seems likely to claim a position in the
twentieth century economics of mining, its particular rôle being to
aid in the determination of the "strike" of mineral-bearing lodes. One
main reason for this conclusion consists in the fact that the
formations which carry metalliferous ores are nearly always more moist
than the surrounding country, and are therefore better conductors of
the electrical current. Indeed there is good ground for the belief
that this moistness of the fissures and lodes in which metals chiefly
occur has been in part the original cause of the deposition of those
metals from their aqueous solutions percolating along the routes in
which gravitation carries them. In the volumes of _Nature_ for 1890
and 1891 will be found communications in which the present writer has
set forth some of the arguments tending to strengthen the hypothesis
that earth-currents of electricity exercise an appreciable influence
in determining the occurrence of gold and silver, and that they have
probably been to some extent instrumental in settling the distribution
of other metals.

The existence of currents of electricity passing through the earth's
crust and on its surface along the lines of least resistance has long
been an established fact. Experiments conducted at Harvard, U.S.A., by
Professor Trowbridge have proved beyond a doubt that, by means of such
delicate apparatus as the telephone and microphone, it is possible for
the observer to state in which direction, from a given point, the best
line of conductivity runs. Under certain conditions the return current
is so materially facilitated when brought along the line of a
watercourse or a moist patch of the earth's crust, that the words
heard through a telephone are distinctly more audible than they are at
a similar distance when there is no moist return circuit. Deflections
of the compass, due to the passing of earth-currents along the natural
lines of conductivity in the soil or the rocks, are so frequently
noticed as to be a source of calculation to the scientific surveyor
and astronomer. It can thus be shown not only that definite lines of
least electrical resistance exist in the earth, but also that natural
currents of greater or less strength are almost constantly passing
along these lines.

Some of the curious and puzzling empirical rules gained from the
life-long experience of miners in regard to the varying richness and
poorness of mineral lodes, according to the directions in which they
strike--whether north, south, east or west--may very probably be
explained, and to some extent justified, by the fuller light which
science may throw upon the conditions determining the action of
earth-currents in producing results similar to those of electro
deposition. If, in a given region of a mineral-bearing country, the
geological formation is such as to lend itself to the easy conduction
of currents in one direction rather than in another, the phenomenon
referred to may perhaps be partially explained. But, on the other
hand, the origin of the generating force which sets the currents in
motion must first be studied before the true conditions determining
their direction can be understood. In other words, much that is now
obscure, including the true origin of the earth's magnetism, must be
to some extent cleared up before the reasons for the seemingly erratic
strike of earth-currents and of richness in mineral lodes can be fully
explained.

Practice, however, may here get some distance ahead of science, and
may indeed lend some assistance to the latter by providing empirical
data upon which it may proceed. When once it is clearly seen that by
delicate electrical instruments, such as the telephone, the microphone
and the coherer as used in wireless telegraphy, the line of least
resistance on any given area of the earth's surface or any given piece
of its crust may be determined, the bearing of that fact in showing
the best lines of moisture and therefore the likeliest lines for
mineral lodes will soon be recognised in a very practical manner.

No class of men is keener or more enterprising in its applications of
the latest practical science to the getting of money than mining
speculators. Nor have they at all missed the significance of moist
bands occurring in any underground workings as a very favourable
augury for the close approach of highly mineralised lodes. If, then,
moisture be favourable, first to the presence of mineral-bearing
country and secondly to the conductivity of electrical lines, it is
obvious that there is a hopeful field for the exercise of ingenuity in
bringing the one into a practical relation to the other.

The occult scientific reasons for the connection may not be
understood; but it is sufficient for practical purposes to know that,
in a certain line from the surface outcropping of a mineral lode,
there has been given a demonstration of less electrical resistance
along that line than is experienced in any other direction; also to
know that such a line of least resistance is proved to have been, in
almost innumerable instances, coincident with the best line of
mineral-bearing country. The case is similar to that of the rotation
of crops in its relation to scientific microbiology. The art of mining
may get ahead of the science of physiography in respect of
earth-currents and lines of least resistance, as showing where mineral
lodes may be expected. Yet there is no doubt whatever that science
will not in the one case lag so far behind as it has done in the
other.

The first notable service rendered by systems of the kind indicated
will no doubt be in connection with the rediscovery of very valuable
lodes which have been followed up for certain distances and then lost.
In an instance of this description much fruitless exploration drives,
winzes and "jump-ups" may have been carried out in the surrounding
country rock near the place where the lode last "cut out"; but, in the
absence of anything to guide the mine manager and surveyor as to the
direction which the search should take, nothing but loss has been
involved in the quest. Several properties in the same neighbourhood
have, perhaps, been abandoned or suspended in operation owing to very
similar causes.

The whole group may perhaps have then been bought by an exploration
company whose _modus operandi_ will be as follows: The terminal of the
electrical exploration plant is fixed at the end of the lode where it
gave out, or else immersed in the water of the shaft which is in
connection with the lode system; and another similar terminal is fixed
by turns in each shaft of the contiguous group. The electrical
resistances offered to the return currents, or to the wireless
vibrations, are then carefully measured; and the direction of the lost
lode is taken to be that which shows the least resistance in
proportion to the distance traversed. The work of carrying out such an
investigation must of necessity be somewhat elaborate, because it may
be necessary to connect in turn each shaft, as a centre, with every
one of the others as subsidiaries. But the guidance afforded even of a
negative character, resulting in the avoidance of useless cutting and
blasting through heavy country, will prove invaluable.

Many matters will require attention, in following out such a line of
practical investigation, which are to some extent foreign to the usual
work of the mining engineer. For example, the conditions which
determine the "short-circuiting" of an earth-current require to be
carefully noted, because it would be fallacious to reason that because
the line of least resistance lay in a certain direction, therefore an
almost continuous lode would be found. Moreover, the electrical method
must only be relied upon as a guide when carefully checked by other
considerations. Other kinds of moist formations, both metalliferous
and non-metalliferous, may influence the lines of least electrical
resistance, besides those containing the particular metal which is
being sought for.

The water difficulty has enforced the abandonment of very many
valuable mines in which the positions of the lodes are still well
known. Sunken riches lying beneath the sea in old Spanish galleons
have excited the cupidity and the ingenuity of speculators and
engineers; but the total amount of wealth thus hidden away from view
is a mere insignificant fraction of the value of the rich
metalliferous lodes which lie below the water level in flooded mines.

The point in depth at which the accumulation of the water renders
further following of the lode impracticable may vary in different
countries. In China, throughout whole provinces, there is hardly a
mine to be found in which the efforts of the miners have not been
absolutely paralyzed directly the water-level was reached. But in
Western lands, as well as in South Africa and Australia, the immense
capacity of the pumps employed for keeping down the water has enabled
comparatively wet ground to be worked to a very considerable depth.

The limit, nevertheless, has been reached in many rich mining
districts. Pumps of the most approved type, and driven by the largest
and most economical steam-engines, have done their best in the
struggle against the difficulty; and yet the water has beaten them.
Rich as are the lodes which lie beneath the water, the mining engineer
is compelled to confess that the metal value which they contain would
not leave, after extraction, a sufficient margin to pay for the
enormous cost of draining the shafts. In some instances, indeed, it
remains exceedingly doubtful whether pumps of the largest capacity
ever attained in any part of the world would cope with the task
entailed in draining the abandoned shafts. The underground workings
have practically tapped subterranean rivers which, to all intents and
purposes, are inexhaustible. Or it may be that the mine has penetrated
into some hollow basin of impermeable strata filled only with porous
material which is kept constantly saturated. To drain such a piece of
country would mean practically the emptying of a lake.

Subaqueous mining is therefore one of the big problems which the
mining engineer of the twentieth century must tackle. To a certain
extent he will receive guidance in his difficult task from the
experiences of those who have virtually undertaken submarine mining
when in search of treasure lost in sunken ships. The two methods of
pumping and of subaqueous mining will in some places be carried out
conjointly.

In such instances the work assigned to the pumping machinery will be
to keep free of water those drives in which good bodies of ore were
exposed when last profitable work was being carried on. All below that
level will be permitted to fill with water, and the work of boring by
means of compressed air, of blasting out the rock and of filling the
trucks, will all be performed under the surface. For the shallower
depths large tanks, open at the top, will be constructed and slung
upon trucks run on rails along the lowest drives. Practically this
arrangement means that an iron shaft, closed at the sides and bottom,
and movable on rails laid above the surface, will be employed to keep
the water out. Somewhat similar appliances have been found very
useful in the operations for laying the foundations of bridges.

The details requiring to be worked out for the successful working of
subaqueous systems of mining are numerous and important. Chief among
these must be the needful provision for enabling the miner to see
through strong glass windows near the bottom of the iron shaft, by the
aid of electric lights slung in the water outside, and thus to
estimate the correct positions at which to place his drills and his
explosives. For this reason the work of the day must be systematically
divided so that at stated intervals the clay and other materials held
in suspension by the disturbed water may be allowed to settle and the
water be made comparatively clear.

Specially constructed strainers for the mechanical filtration of the
water near the ore face, and probably, also, chemical and other
precipitates, will be largely resorted to for facilitating this
important operation. Beside each window will be provided strong
flexible sleeves, terminating in gloves into which the miner can place
his hands for the purpose of adjusting the various pieces of machinery
required. Beyond this, of course, every possible application of
mechanical power operated from above will be resorted to, not only for
drilling, but also for gripping and removing the shattered pieces of
rock and ore resulting from the blasting operations.

From the unwatered drive or tunnel downwards, the method of working as
just described may be characterised as an underground application of
the "open-cut system". No elaborate honeycombing of the country below
the water-level will be economically possible as it is when working in
dry rock. But then, again, it is becoming plain to many experts in
mining that, in working downwards from the surface itself, the future
of their industry offers a wide field for the extension of the
open-cut system. In proportion as power becomes cheaper, the expense
attendant upon the removal of clay, sand, and rock for the purpose of
laying bare the cap of a lode at a moderate depth becomes less
formidable when balanced against the economy introduced by methods
which admit of the miner working in the open air, although at the
bottom of a kind of deep quarry. While the system of close mining will
hold its own in a very large number of localities, still there are
other places where the increasing cheapness of power for working an
open-cut and the coincident increase in the scarcity and cost of
timber for supporting the ground, will gradually shift the balance of
advantage on to the side of the open method.

At the same time great improvements are now foreshadowed in regard to
the modes of working mines by shafts and drives. Some shafts will in
future be worked practically as the vertical portions of tramways,
having endless wire ropes to convey the trucks direct from the face or
the stope to the reduction works, and thus an immense saving will be
effected in the costs incidental to mining. From the neighbourhood of
the place at which it has been won, the ore will be drawn in trucks,
attached to the endless wire rope, first along the drive on the
horizontal, and then up an incline increasing in sharpness till the
shaft is reached, where the direction of motion becomes vertical. Near
the surface, again, there is an incline, gradually leading to the
level of the ground, or rather of the elevated tramway from which the
stuff is to be tipped into the mill, or, if it be mullock, on to the
waste heap. The return of each truck is effected along the reverse
side of the endless wire-rope cable.

Ventilation is an incidental work of much importance which it becomes
more practicable to carry out in a satisfactory manner when an endless
system of truck conveyance has been provided, reaching from the
ore-face to the mill, and thence back again. The reason is mainly that
the same routes which have been prepared for this traffic are
available for the supply of air and for the return current which must
carry off the accumulated bad gases from the underground workings.
Fans, operated by the cable at various places along the line of
communication, keep up a brisk exchange of air, and the coming and
going of the trucks themselves help to maintain a good, healthy
atmosphere, even in the most remote parts of the mine. In very deep
mines, where the heat becomes unbearable after a few minutes unless a
strong wind be kept going underground, the forward and backward
courses for traffic and ventilation together are specially
advantageous.

Prices during the twentieth century will depend more definitely upon
the cost of gold-mining than they have ever done at any former time in
the world's history. In spite of all the opposition which fanaticism
and ignorance could offer to the natural trend of events in the
commercial and financial life of the world, the gold standard now
rests on an impregnable base; and every year witnesses some new
triumph for those who accept it as the foundation of the civilised
monetary system. This being the case, it is obvious that the
conditions affecting the production of gold must possess a very
peculiar interest even for those who have never lived within hundreds
of miles of any gold mine. To all intents and purposes the habit of
every man is to measure daily and even hourly the value of his efforts
at producing what the economist calls "utilities," against those of
the gold miner.

If, therefore, the latter successfully calls to his aid mechanical
giants who render his work easier and who enable him to throw into the
world's markets a larger proportion of gold for a given amount of
effort, the result must be that the price of gold must fall, or, in
other words, the prices of general commodities must rise. If, on the
other hand, all other industries have been subjected to the like
improved conditions of working, the effect must be to that extent to
balance the rise and keep prices comparatively steady.

From this point of view it will be seen that the interests of all
those who desire to see a rise in general prices are to a large extent
bound up in the improvement of methods for the extraction of gold. The
question of cheap power does not by any means monopolise the data upon
which such a problem can be provisionally decided; and yet it may be
broadly stated that in the main the increased output of gold in the
future depends upon the more economical production and application of
power. Measured against other commodities which also depend mainly
upon the same factor, gold will probably remain very steady; while, in
contrast with those things which require for the production taste and
skill rather than mere brute force or mechanical power, gold will fall
in value. In other words, the classes of articles and services
depending upon the exercise of man's higher faculties of skill, taste,
and mental power will rise in price.

Getting gold practically means, in modern times, crushing stone. This
statement is subject to fewer and fewer exceptions from one decade to
another, according as the alluvial deposits in the various
gold-producing countries become more or less completely worked out. A
partial revival of alluvial mining has been brought about through the
application of the giant dredger to cheapening the process of
extracting exceedingly small quantities of gold from alluvial drift
and dirt. Yet on the whole it will be found that the gold-mining
industry, almost all the world over, is getting down to the bed-rock
of ore-treatment by crushing and by simple methods of separation. Thus
practically we may say that the cost of gold is the cost of power in
those usually secluded localities where the precious metal is found in
quantities sufficient to tempt the investment of capital.

From this it may be inferred that the cheap transmission of power by
the electric current will effect a more profound revolution in the
gold-mining industry than in almost any other. The main deterrent to
the investing of money in opening up a new gold mine consists in the
fact that a very large and certain expense is involved in the
conveyance of heavy machinery to the locality, while the results are
very largely in the nature of a lottery. When, however, the power is
supplied from a central station, and when economical types of crusher
are more fully introduced, this deterrent will, to a large extent,
disappear. The cables which radiate from the central electric
power-house in all directions can be very readily devoted to the
furnishing of power to new mines as soon as it is found that the older
ones have been proved unprofitable.

No one will think of carrying ore to the power when it is far more
economical and profitable to carry power to the ore. In this
connection the principle of the division of labour becomes very
important. In its bearing upon the mining industry generally, whether
in its application to the precious metals or to those which are termed
the baser, and even in the work of raising coal and other
non-metalliferous minerals, the fact that nearly all mines occur in
groups will greatly aid in determining the separation of the work of
supplying power, as a distinct industry from that of mining.

Ore-dressing is an art which was in a very rudimentary state at the
middle of the nineteenth century, when the great discoveries of gold,
silver and other metals began to influence the world's markets in so
striking a manner. The ancients used the jigger in the form of a
wicker basket filled with crushed ore and jerked by hand up and down
in water for the purpose of causing the lighter parts to rise to the
top, while the more valuable portions made their way to the bottom. In
this way the copper mines of Spain were worked in the days of the
Roman Empire, and probably the system had existed from time
immemorial.

Fifty or sixty years ago the miner had got so far as to hitch his
jigging basket or sieve on to some part of his machinery, generally
his pumping engine, and thus to avoid the wearing muscular effort
involved in moving it in the water by hand. It was not until the
obvious mistake of using a machine which permitted the finest, and
sometimes the richest, parts of the ore to escape had been for many
years ineffectually admitted, that the "vanner," or moving endless
band with a stream of water running on it, was invented with the
special object of treating the finer stuff.

Jiggers and vanners form the staple of the miner's ore-dressing
machinery at the present day. The efficiency of the latter class of
separating machines, working on certain kinds of finely crushed ore,
is already so great that it may be said without exaggeration that it
could hardly be much improved upon, so far as percentage of extraction
is concerned; and yet the waste of power which is involved is
something outrageous. For the treatment of a thin layer of slimes,
perhaps no thicker than a sixpence, it is necessary to violently
agitate, with a reciprocating movement, a large and heavy framework.
Sometimes the quantity of stuff put through as the result of one
horse-power working for an hour is not more than about a
hundredweight. The consequence is that in large mines the nests of
vanners comprise scores or even hundreds of machines. When shaking
tables are used, without the addition of the endless moving bands,
good work can also be done; but the waste of power is still excessive.

The vanning spade and shallow washing dish are the prototypes of this
kind of ore-dressing machinery. Let any one place a line of
finely-crushed wet ore on a flat spade and draw the latter quickly
through still water, at the same time shaking it, and the result on
inspection, if the speed has not been so great as to sweep all the
fine grains off the surface, will be that the heavier parts of the ore
will be found to have ranged themselves on the side towards which the
spade was propelled in its progress through the water. A sheet of
glass serves for the purpose of this experiment even better than a
metal implement; but the spade is the time-honoured appliance among
miners for testing some kinds of finely crushed ore by mechanical
separation.

It is to be observed that, besides the shaking motion imparted to the
apparatus, the only active agency in the distribution of the particles
is the sidelong movement of the spade relatively to the water. But it
makes little or no difference whether the water moves sidelong on the
spade or the latter progresses through the liquid; the ore will range
itself accurately all the same. Consequently, if a circular tank be
used, and if the water be set in rotary motion, the ore on a sheet of
glass, held steady, will arrange itself in the same way. If the ore be
fed in small streams of water down the inclined surfaces of sloping
glass, or other smooth shelves set close to and parallel with one
another near the periphery of such a vessel of moving water, the
resultant motions of the heavy and of the light particles
respectively, in passing down these shelves, will be found to be so
different that the good stuff can be caught by a receptacle placed at
one part, while the tailings fall into another receiver which is
differently situated at the place where the lighter grains fall.

The main essential in this particular application of the art of
vanning is simply that the water should move or drift transversely to
lines of ore passing, while held in suspension with water, down a
smooth sloping surface. In dealing with some very light classes of
ore, and especially such as may naturally crush very fine--that is to
say, with a large proportion of impalpable "slimes"--there is a
decided advantage in causing the water to drift sidelong on the smooth
shelf by other means than the motion in a circular tank.

Adopting nearly the form of the "side delivery manner," in which the
moving band is canted to the side and the stuff runs off sideways, the
sloping smooth shelf can be worked for ore separation with merely the
streams of water holding the fine sand in suspension running down at
fixed intervals. A glass covering is placed very close to this surface
on which the streams run; and between the two is driven laterally a
strong current of wind by means of a blast-fan, which causes each
stream of water to drift a little sidewards, carrying with it the
lighter particles, but leaving on its windward side a line of nearly
pure ore. These small runlets can be multiplied, on a shelf measuring
six or eight feet in length, to such an extent that the machine can
put through as much ore as a dozen vanners, consuming only a mere
fraction of the power necessary to drive one machine of the older
type.

Cyanide solution, instead of water, is very advantageously employed
for this kind of operation in the case of extracting gold from crushed
ore. The method is to pump the liquid from the tanks in which it is
stored and to allow it to flow back by way of the vanning apparatus,
thus providing not only for catching the grains of gold by the
concentrating machine, but also for the dissolving of the fine
impalpable gold dust, or natural precipitate, by the action of the
cyanide of potassium.

Upon the use of this latter chemical will be based the main
improvements in the gold-mining industry during the twentieth century;
and, conversely, the applications of the old system of amalgamating
with mercury, in order to catch the golden particles, will be
gradually restricted. Fine concentrators, worked with cyanide
solution, perform three operations at once, namely, first, the
catching of the free gold grains; second, the production of a rich
concentrate of minerals having gold in association and intended for
smelting; and, third, the dissolving of the finest particles by the
continual action of the chemical.

In fact it is in the treatment of complex and very refractory ores
generally, whether of the precious or of the baser metals, that the
finer applications of the art of the ore-dresser will receive their
first great impetus. The vanner, as well as the jigger, will become an
instrument of precision; and in combination with rushing appliances
operated by cheap power in almost unlimited quantities it will
materially assist in multiplying the world's supply of metals. This
again will aid in promoting the further extension of machinery. Gold
will be produced in greater abundance for what is called the machinery
of commerce; and the base metals, particularly the new alloys of steel
and also copper and aluminium, will be more largely produced for
engineering and electrical purposes.

The importation--particularly to England and Scotland--of large
quantities of highly-concentrated iron ore will cause one of the first
notable developments in the mining and ore-treatment of the twentieth
century so far as the United Kingdom is concerned. The urgent
necessity for an extension in the manufacture of Bessemer steel, and
of the new and remarkable alloys in which very small quantities of
other metals are employed in order to impart altogether exceptional
qualities to iron, must accentuate the demand for those kinds of ore
which lend themselves most readily to the special requirements of the
works on hand. Hence the question of the transport of special kinds of
iron ore over longer distances will have to be faced (as it has been
already to a limited degree), and not only in reference to ores
containing a low percentage of phosphorus and therefore exceptionally
suitable for the Bessemerising process, but also in regard to ores
which are amenable to magnetic separation.

Magnetite, indeed, must bulk more largely in the future as a source of
iron, particularly because it is susceptible of magnetic separation, a
process which as yet is only in its infancy. Containing, as it does, a
larger percentage of iron than any other source from which the metal
is commercially extracted, its employment as an ore results in great
economy of fuel, as well as a reduction in the proportionate costs of
transport. When ores of iron require to be brought from oversea
places, it is obvious that those which will concentrate to the purest
product possible, and which are in other respects specially applicable
to the production of grades of steel of exceptional tensile strength,
will have the preference.

Magnetic concentration, or the separation of an ore from the waste
gangue by the attraction of powerful electro-magnets, must therefore
occupy a much more prominent place in the metallurgy of the future
than it has in that of the past. Not only may ironstone containing
magnetite be separated from other material, but several important
minerals acquire the property of becoming magnetic when subjected to
the operation of roasting, sometimes through a sulphide being
converted into a magnetic oxide.

By the use of powerful electro-magnets, the poles of which are brought
to a point or to a nearly sharp knife-edge, the intensity of the
magnetic field can be so enormously increased that even minerals which
are only feebly magnetic can readily be separated by being lifted away
from the non-magnetic material. In some systems the crushed ore is
simply permitted to fall in a continuous stream through a strong
magnetic field, and the magnetic particles are diverted out of the
vertical in their descent by the operation of the magnets.

Nor is it only those minerals that actually become themselves magnetic
on being roasted which can be so differentiated from the material with
which they are associated as to be amenable to magnetic separation.
Even differences in hygroscopic properties--that is to say, in the
degree of avidity with which a mineral takes up moisture from the
atmosphere--may be made available for the purpose of effecting a
commercially valuable separation. This is especially the case with
some complex ores in which one constituent, on being roasted, acquires
a much greater hygroscopic power than the others, the grains of the
crushed and roasted ore becoming damp and sticky while those of the
other minerals remain comparatively dry. By mixing with an ore of this
kind--after it has been allowed to "weather" for a short time--some
finely-powdered magnetite the strongly hygroscopic constituents can be
made practically magnetic, because the magnetic impalpable dust
adheres to them, while it remains separate from the grains of the
other minerals.

Hardness--as well as magnetic attraction--is a property of ore which
has as yet been made available to only a very slight extent as the
basis of a system of separation. If a quantity of mixed fragments of
glass and plumbago be pounded together in a mortar with only a
moderate degree of pressure, so as to avoid, as far as possible, the
breaking of the glass, there will soon come a stage at which the
softer material can be separated from the harder simply by means of a
fine sieve. There are many naturally-existing mineral mixtures in the
crushing of which a similar result occurs in a very marked degree;
and, indeed, there are none which do not show the peculiarity more or
less, because the constituents of an ore are never of exactly the same
degree of hardness. When the worthless parts are the softer and
therefore have the greater tendency to "slime," the ore is very
readily dressed to a high percentage by means of water.

But when the reverse is the case, and the valuable constituents
through their softness get reduced to a fine pulp long before the
other parts, the ordinary operations of the ore-dresser become much
more difficult to carry out. Most elaborate ore-reduction plants are
constructed with the view to causing the crushing surfaces, whether of
rolls or of jaws, to merely tap each piece of stone so as to break it
in bits without creating much dust. This operation is repeated over
and over again; but the stuff which is fine enough to go to the
concentrator is removed by sieving after each operation of the kind;
and the successive rolls or other crushers are set to a finer and
finer gauge, so that there is a progressive approach to the conditions
of coarse sand, which is that specially desired by the ore-dresser.

Much of this elaboration will be seen to be needless, and, moreover,
better commercial results will be obtained when it is more clearly
perceived that the recovery of a valuable ore in the form of a fine
slime may be economically effected by the action of grinders specially
constructed for the purpose of permitting the hard constituents of the
ore to remain in comparatively large grains, while the other and
softer minerals are reduced to fine slimes or dust. In other words, a
grinding plant, purposely designed to carry out its work in exactly
the opposite way to that which has been described as the system aimed
at in ordinary crushing machinery, has its place in the future of
metallurgy. Light mullers are employed to pound, or to press together,
the crushed grains for a given length of time, and then sieving
machinery completes the operation by taking out the dust from the more
palpable grains.

In some cases it will be found that an improvement can be effected by
bringing about the separation of a finer grade of dust than could be
taken out by any kind of sieve which is commercially practicable on
the large scale. This is more particularly the case in regard to
sulphide ores containing very friable constituents carrying silver. A
fine dry dust-separator may then be employed constructed on the
principle of a vibrating sloping shelf which moves rhythmically,
either in a horizontal circle or with a reciprocal motion, and which
at the same time alters its degree of inclination to the horizontal.
When the shelf is nearly level its vibration drives the coarser
particles off; but the very finest dust does not leave it until it
assumes nearly a vertical position. A large nest of similar shelves,
set close to, and parallel with, one another, can separate out a great
quantity of well-dried slimes in a very short space of time.




                             CHAPTER IX.

                              DOMESTIC.


The enormous waste involved in the common methods of heating is one of
the principal defects of household economy which will be corrected
during the twentieth century. Different authorities have made varying
estimates of the proportion between the heat which goes up the chimney
of an ordinary grate, and that which actually passes out into the room
fulfilling its purpose of maintaining an equable temperature; but it
cannot be denied that, at the very least, something like three-fourths
of the heat generated by the domestic fires of even the most advanced
and civilised nations goes absolutely to waste--or rather to worse
than waste--because the extra smoke produced in creating it only
serves to pollute the atmosphere. In the cities some degree of
progress has been made in the introduction of heating appliances which
really give warmth to a room without losing at least seventy-five per
cent. of their heat; but in the country districts, where open
fireplaces are the rule, it is not unusual to find that more than
ninety per cent. of the heat produced behind the domestic hearth goes
up the chimney.

Sentiment has had a great deal to do with retarding progress in the
direction of improved house-heating appliances. For countless ages
"the hearth" has been, so to speak, the domestic altar, around which
some of the most sacred associations of mankind have gathered, and
popular sentiment has declared that it is not for the iconoclastic
inventor or architect to improve it out of existence, or even to
interfere seriously with either its shape or the position in the
living room from which it sheds its genial warmth and cheerfulness
around the family circle. A recognition of this ineradicable popular
feeling was involved in the adoption of the grate, filled with glowing
balls of asbestos composition, by the makers of gas-heating apparatus.
The imitation of the coal-filled grate is in some cases almost
perfect; and yet it is in this close approximation to the real article
that some lovers of the domestic fuel-fire find their chief objection,
just as the tricks of anthropoid animals--so strongly reminiscent of
human beings and yet distinct--have the effect of repelling some
people far more than the ways of creatures utterly unlike man in form
and feature.

Taking count of the domestic attachment to a real fuel-filled
fireplace or grate as one of the principal factors in the problem of
domestic heating, it is plain that one way of obviating the waste of
heat which is at present incurred, without doing violence to that
sentiment, is by making better use of the chimney. The hot-air pipes
and coils which are already so largely used for indoor heating offer
in themselves a hint in this direction. Long pipes or coils inserted
in the course taken by the heated air in ascending a chimney become
warm, and it is possible, by taking such a pipe from one part of the
room up the passage and back again, to cause, by means of a small
rotating fan or other ventilating apparatus, the whole of the air in
the chamber to circulate up the chimney and back again every few
minutes, gathering warmth as it goes. In this way, and by exposing as
much heating surface to the warm air in the chimney as possible, the
warmth derived by an ordinary room from a fuel fire can be more than
doubled.

At the same time the risk of spreading "smuts" over the room can be
entirely avoided first by keeping the whole length of pipe perfectly
air-tight, and attaching it in such a way as to be readily removed for
inspection; and, secondly, by placing the outward vent in such a
position that the gentle current must mount upwards, and any dust must
fall back again into a wide funnel-shaped orifice, and by covering the
latter with fine wire gauze. An apparatus of this kind acts as a
remover of dust from the room instead of adding any to it. One
necessity, however, is the provision of motive power, very small
though it be, to work the fan or otherwise promote a draught.

Electric heating is, however, the method which will probably take
precedence over others in all those cases where systems are tried on
their actual merits apart from sentiment or usage. The wonderful
facility afforded by the electric heating wire for the distribution of
a moderate degree of warmth, in exactly the proportions in which it
may be needed, gives the electric method an enormous advantage over
its rivals. The fundamental principle upon which heating by
electricity is generally arranged depends upon the fact that a thin
wire offers more electrical resistance to the passage of a current
than a thick one, and therefore becomes heated. In the case of the
incandescent lamp, in which the carbon filament requires to be raised
to a white heat and must be free to emit its light without
interference from opaque matter, it is necessary to protect the
resisting and glowing material by nearly exhausting the air from the
hermetically sealed globe or bulb in which it is enclosed.

But in electrical house-warming, for which a white heat is not
required and in which the necessary protection from the air can be
secured by embedding the conveying medium in opaque solid material,
the problem becomes much simpler, because strong metallic wires can be
used, and they may be enclosed in any kind of cement which does not
corrode them and which distributes the heat while refusing to conduct
the electric current. A network of wire, crossing and recrossing but
always carrying the same current, may be embedded in plaster and a
gentle heat may be imparted to the whole mass through the resistance
of the wires to the electricity and their contact with the
non-conducting material.

Concurrently with this method of heating there is gradually being
introduced a practice of using metallic lathing for the plastering of
dwelling-rooms in place of the old wooden battens generally employed
for lath-and-plaster work. The solution of the practical problem which
has to be faced seems to depend upon the prospect of effecting a
compromise between the two systems, introducing thin resisting wire as
the metallic element in such work, but making all other components
from non-conducting material. In the event of any "cut-out" or
"short-circuiting" occurring through accidental injury to the wall, it
would be very inconvenient to be compelled to knock away the plaster.
Moreover, it is not necessary for ordinary warming purposes that the
whole of the wall, up to the ceiling, should be heated.

Accordingly the system which is likely to commend itself is that of
constructing panels on some such principle as the one already
described, and affixing them to the wall, forming a kind of solid dado
from three to four feet from the floor. These can be fastened so as to
facilitate removal for examination and repairs. When the current is
switched on they are slowly warmed up by the heat generated through
the resistance of the wires, and the air in the room is gently heated
without being vitiated or deprived of its oxygen as it is by the
presence of flames, whether of fuel or of gas. Warming footstools will
also be provided, and a room heated in this way will be found
eminently comfortable to live in.

This method of house-warming having once obtained a decided lead
within the cities and other localities where a cheap electric current
is available, somewhat similar systems, adapted for the heating of
walls by hot air in tubes, instead of by resistant wires, will be
largely adopted in the rural districts, more particularly in churches
and other places of public assemblage. The progress made in this
direction during the last few years of the nineteenth century is
already noteworthy, but when electric-heating really gets a good
chance to force the pace of improvement, the day will soon arrive when
it will be regarded as nothing less than barbarous to ask people to
sit during the winter months in places not evenly warmed all through
by methods which result in the distribution of the heat exactly as it
is wanted.

Ventilation is another household reform which will be very greatly
accelerated by the presence of electric power of low cost. The great
majority of civilised people, as yet, have no idea of ventilation
excepting that highly unreasonable kind which depends upon leaving
their houses and other buildings partly open to the outside weather.
One man is sitting in church under a down draught from an open window
above him, while others, in different parts of the same building, may
be weltering in the heat and feeling stifled through the vitiated air.
In dwelling-houses the great majority of living rooms really have no
other effective form of ventilation than the draught from the
fireplace. The strength of this draught, again, is regulated to a very
large extent by the speed and direction of the outside wind.

In calm and sultry weather, when ventilation is most needed, the
current of air from the fireplace may be very slight indeed; while in
the wild and boisterous days succeeding a sudden change of weather,
the living rooms are subjected to such a drop in temperature and are
swept by such draughts of cold air that the inmates are very liable to
catch colds and influenza. Hence has arisen in the British Islands,
and in the colder countries of Europe and America, the very general
desire among the poorer classes to suppress all ventilation. Rooms are
closed at the commencement of winter and practically remain so until
the summer season. Many people whose circumstances have improved, and
who pass suddenly from ill-ventilated houses to those which have
better access to the outside air, find the change so severe upon their
constitutions and habits that they give a bad name to everything in
the shape of ventilation. Meanwhile the dread of draughts causes
people to exclude the fresh air to such an extent that consumption and
many other diseases are fostered and engendered.

All this arises mainly from the very serious mistake of imagining that
it is possible to move air without the exercise of force. In the case
of the draught caused by a fire no doubt an active force is employed
in the energy of the heated air ascending the chimney, and in the
corresponding inrush. This latter is usually drawn from below the
door--the very worst place from which it can be taken, seeing that in
the experience of most people it is by getting the feet chilled,
through draughts along the floor, that the worst colds are generally
contracted. Fireplaces are not unusually regarded as a direct means
for ventilation, and with regard to nearly all the devices commonly
adopted in houses and public buildings, it may be said that they lack
the first requisite for a scientific system of renewing the air,
namely a source of power by means of which to shift it from outside to
inside, and _vice versâ_. There is no direction in which a more
pressing need exists for the distribution of power in small quantities
than in regard to the ventilation of private and public edifices.

The circular fan, placed in the centre piece of the ceiling and
controlled by an electric switch on the wall, is the principal type of
apparatus applicable to the purposes of ventilation. As electric
lighting of dwelling-houses becomes more common, and ultimately almost
universal within cities, the practice will be to arrange for lighting
and for ventilation at the same time. But, unfortunately, the current
now principally employed for electric lighting and consisting of a
series of impulses, first in one direction and then in the opposite,
"alternating" with wonderful rapidity, is not well adapted for
driving small motors of the types now in use. One improvement in
domestic economy greatly needed in the twentieth century consists
in the invention of a really effective simple and economical
"alternate-current" motor. This is a matter which will be referred to
in dealing with electrical machines. That the problem will be solved
before many years have passed there is no good reason to doubt.

In the meantime many laudable endeavours are being made towards the
application of the pressure from water pipes to the purpose of driving
ventilating fans. The extreme wastefulness of power and of water
involved in this method of dealing with the difficulty may be
partially overlooked on account of the very small amounts required to
produce an effect in the desired direction; and yet there is no doubt
that a recognition of the wastefulness acts to some extent as a
deterrent to artificial ventilation. The benefits of the system are
not sufficiently obvious or showy to induce any class of people,
excepting physicians and persons fully acquainted with the principles
of hygiene, to sanction a material outlay upon the object. When an
exactly suitable alternate-current motor has been invented the
standard electric light installation will be practically one apparatus
with the ventilating fan, and the cost of the latter will hardly be
felt as a separate item.

In cooking there is in existing ordinary methods the same enormous
waste of heat as there is in the warming of rooms. Something, no
doubt, has been done in the direction of economy by the invention of
new and improved forms of stoves, but a great preponderance of the
heat generated in the fire of even the best stove goes up the chimney.
The electric oven, as already invented, is perhaps the nearest
approach to a really economical "cooker" that has yet been proposed;
but even before the general adoption of such an apparatus there will
be ample room for improvement in the cooking stove, first as regards
insulation, and secondly in the distribution of the fuel around the
objects to be heated. One principal cause of the waste that goes on
arises from the fact that the fire burns away from the place at which
its heat is most beneficially applied, and no means are adopted, as in
the case of the candle in a carriage lamp, for keeping it up to the
required level. Additions of fuel are made from the top with the
immediate effect of checking the heat.

A great advance in economy of fuel will take place when the household
coal intended for cooking purposes is ground up together with the
proper proportions of certain waste products of chemistry, so as to
make a "smouldering mixture" which can be kept regularly supplied to a
shallow or thin fire box by pressure applied from beneath or at the
parts farthest away from the objects to be heated. An oven, for
instance, may be surrounded by a "jacket" filled with ground
smouldering mixture having a non-conducting insulator outside and a
connection with a chimney. The heat from the fuel is thus kept in
close proximity to the objects requiring to be cooked, and
comparatively small waste results.

It is by taking advantage of their superior facilities in the same
direction that gas and inflammable oils have already made their mark
in the sphere of domestic cookery. Regarded as fuel their initial cost
may be relatively heavy; and yet, owing to their more exact method of
application, they often effect a saving in the end. Not only do they
bring the fire closer to the articles to be heated or cooked, but
they also make it easy for the fire to be turned off or on, and this
in itself is an important source of economy. Still, with the advent of
cheaper and more accessible power in every centre of population, the
cost of grinding coal and of mixing it in order to form a fuel
comparable in respect of convenience and economy with gas and oil will
be so greatly reduced that the "black diamond" will still continue to
challenge its rivals in the arena of competition presented by the
demands of domestic economy.

Light, as well as heat and air, requires to be evenly and equably
distributed throughout the dwelling-house before anything approaching
an ideal residence can be secured. As the science of hygiene advances
it is demonstrated more and more clearly that sunlight--and even
diffused daylight--may be used as a most effective weapon against the
spread of disease. Alternations of deep gloom in the dwelling-house
with the superior light resulting from brighter weather produce many
kinds of nervous derangement, not the least deleterious of which arise
from the unnecessary strain to which the eyesight is subjected. The
promise of the future is that, through the abundance of windows
provided in the walls, roofs and porches of our dwelling-houses--but
all supplemented with shutters and blinds of various kinds--there
shall be a possibility of regulating, far more accurately than at
present, the accessibility of light from outside according to the
brightness or dulness of the day.

It is hardly to be expected that many people will build "Crystal
Palaces" in which to reside; but with the immense progress that is
being made in the construction of dwellings with iron or steel frames,
and in the adaptation of various materials so that they may serve for
building purposes in conjunction with metallic frameworks, it seems
clear that many roofs, as well as large portions of walls, will in
future be made on the composite principle, using steel and glass.
These will, to a large extent, be permanently sheltered from the
direct rays of the sun when high in the heavens, by shutters
constructed on the louvre principle so that they may admit the light
from the sky continually, but actual rays or beams of sunlight only
for a short time after sunrise and at the close of day. The ceilings,
if any are provided under the roofs, will also be glazed.

The obstacles presented in the way of such a reform in a city like
London may at first sight seem so serious as to be practically
insuperable. Long rows of three or four storied houses certainly offer
but few facilities for the admission of light through the roofs of
any but the rooms on the top floors, and yet it is in the
dwelling-houses of this type that the depression caused by gloom and
the absence of light during the hours of day are most severely felt as
a source of nervous depression. Evolution in a matter of this sort
will take place gradually and along the line of least resistance.
Portions of courts, areas and yards will be glazed over in the way
described; and it will be found that those rooms which are thus
enclosed and sheltered from the wind and rain, but left open to the
daylight, constitute the most cheerful sitting places in the houses.
Then, as rebuilding and alterations proceed, many houses will
gradually be remodelled--at least as regards some of their rooms--in
the same direction. Physicians will become increasingly insistent on
the necessity for admitting plenty of light into the abodes of the
sick, more particularly of families inclined towards consumption.

A very large trade will spring up during the twentieth century in
household cooling apparatus for use in hot climates. The colonial
expansion towards which all European races are now tending inevitably
means that very many thousands of persons whose ancestors have been
accustomed to life in cold or temperate climates, will be induced to
dwell in the dry and warm, or in the humid tropical regions of the
earth. It will be an important task of the British, Continental and
American machinists of the twentieth century to turn out convenient
pieces of apparatus which shall be available for ventilating houses,
especially during the night, and for reducing the temperature in them
to something approaching that which is natural to the inmates. The old
clumsy punkah will be replaced by circular fans keeping up a gentle
current of air with a minimum of noise or annoyance of any kind.

At present it is only in specially favoured circumstances that these
quiet-working circular punkahs can be actuated by mechanical force,
that is to say where a prime motor, or an electric current, or a
reticulated water supply for driving a suitable machine may be at
hand. In other situations the use of compressed air or gas may be
resorted to, and for this purpose small capsules, similar to those
already introduced for making soda water by the liberation of
compressed carbonic acid gas, will be found handy. For a very small
sum of money the householder will be able to purchase a sufficient
number of capsules to ensure motive power for his fan during a week of
hot nights.

A convenient form of small motor suitable for being driven by
compressed air or gases in this way is one in which a diminutive
turbine or other wheel is set at the bottom of a thin tube of mercury.
The capsule, being fastened to the lower end of this apparatus,
liberates at very short intervals of time bubbles of air or gas,
which, in the upward ascent, drive the wheel. The arrangement depends
upon the fact that a stream of gas ascending in a heavy liquid behaves
in the same way as a stream of water descending by its own weight and
turning a water-wheel. It supplies what is perhaps the simplest and
most inexpensive small motor available for the lightest domestic work
to which a gentle but continuous source of power is applicable.

For actually cooling the air, as well as keeping it in motion, similar
devices will be resorted to, with the addition of the circulation of
the current of air through coils of pipes laid under the surface of
the ground. In this way householders will have all the advantages of
living in cool underground rooms without incurring the discomforts and
dangers which are often inseparable from that mode of life. In the
coastal regions, which usually have the most trying climates for
Europeans living in tropical countries, a method of cooling the houses
will be based on the fact that at moderate depths in the sea the
prevailing temperature is a steady one, not much above the freezing
point of water. Almost every seaport town within the tropics--where
white residents in their houses swelter nightly in the greatest
discomfort from the heat--is in close proximity to deep ocean water,
in which, at all seasons of the year, the regular temperature is only
about thirty-four degrees Fahr. The cost of steel piping strong enough
to withstand the pressure of the water in places which possess
absolutely the coolest temperature of the ocean would be very heavy;
but, on the other hand, the actual reduction of heat demanded for the
satisfactory cooling of the air in a dwelling-room is not by any means
great, and at quite shallow depths the heat of the air can be
satisfactorily abstracted by the sea water surrounding coils of pipes.

Even in colder climates it seems likely that similar systems will be
found useful in producing a preliminary reduction in the temperature
of the air employed in keeping fresh foodstuffs such as meat, fruits
and vegetables. Fruits especially, when placed in suitable
receptacles, and stored at temperatures quite steady at about the
freezing point of water, will not only be readily kept on land from
one season to another, but will be transported to markets thousands
of miles distant from the growers, and sold in practically the same
condition as if they had just been picked from the trees. During the
twentieth century the proportion of the fruit eaters among the peoples
of the great manufacturing countries will be very largely augmented,
and this result will be brought about mainly through the
instrumentality of methods of keeping perishable produce free from
deterioration by maintaining it almost at the freezing point--a
temperature at which, under suitable conditions as regards exclusion
of moisture, and steadiness of hygrometric pressure, the germs of
decay in food are practically prevented from coming to maturity.

For the cooling of dwelling-rooms in places distant from the sea,
various systems, depending upon the supply of dry cold air from
central stations through pipes to the dwellings of subscribers, will
no doubt be brought into operation. This, however, will only be
practicable in the more populous localities having plenty of residents
ready to contribute to the expense. For more isolated houses the
cooling and ventilating apparatus of the future may be a modification
of the "shower-blast" which has been successfully adapted to
metallurgical purposes. When downward jets of water, as in a
shower-bath, are enclosed in a large pipe connected horizontally with
a room but having facilities for the escape of the water underneath, a
strong draught of cool air is created, and the prevailing temperature
is quickly reduced. An apparatus of this kind may be intended for
application either to the ventilators or to the windows of rooms.

Lifts for conveying persons from one storey of a building to another
will probably undergo a considerable amount of modification during the
next few years. The establishment of central electric stations and the
distribution of electricity for lighting and for power will offer a
very great premium upon the preference for electric motors for lifts.
As soon as a maximum of efficiency, combined with the minimum of cost,
has been attained, there will be a demand for the introduction of
lifts in positions where the traffic is not large enough to warrant
the constant presence of an attendant. In fact the desire will be for
some kind of elevator which shall be just as free to the use of each
individual as is the staircase of an ordinary house.

For this purpose, inclined planes having moving canvas or similar
ramps will be extensively brought into use. The passenger steps upon
what is practically an endless belt having suitable slats upon it to
prevent his foot from slipping, and, as the hand-railing at the side
of this moves concurrently, he is taken up, without any effort, to the
landing on which he may alight quite steadily. When this idea, which
has already been brought into operation, has been more fully
developed, it will be seen that a large circular slowly-revolving
disc, set at an angle and properly furnished, will supply a more
convenient form of free elevator. One side will be used by those who
are going up and the other by those who wish to come down. The "well"
of the staircase for such a lift is made in elliptical form, like the
shadow projection of a circle. Steps can be provided so that, when not
in motion, the lift will be a staircase not differing much from the
old style.




                              CHAPTER X.

                        ELECTRIC MESSAGES, ETC.


The telegraphic wire in the home and street will fulfil a very
important part in the economy of the twentieth century. For conveying
intelligence, as well as for heating, cooking and lighting, the
electric current will become one of the most familiar of all the
forces called in to assist in domestic arrangements. The rapidity with
which the electric bell-push has taken the place of the old-fashioned
knocker and the bell-hanger's system affords one indication of the
readiness with which those forms of electric apparatus which are
adapted to all the purposes of communicating and reminding will
recommend themselves to the public during the twentieth century.

In another direction the eagerness with which every advance in the
telephone is hailed by the people may well offer an augury of rapid
progress in the immediate future. In this department invention will
aim just as much at simplification as at elaboration; and some of the
pieces of domestic electrical apparatus universally used during the
twentieth century will be astonishingly cheap.

The call to awake in the morning will, in cities and towns, be made by
wireless telegraphy, which will also be used for the purpose of
regulating the domestic clocks, so that if desired any suitable form
of clock alarm may be used with the most perfect confidence. A
tentative system of this kind has been adopted in connection with
certain telephone exchanges, in which special officers are told off
whose duty it is to call those subscribers who have paid the small fee
covering the expense. These officers are required to time their
intimations according to the previously expressed wishes of
subscribers. This kind of service, as well as the regulation of the
household clock, is eminently a department of domestic economy in
which wireless telegraphy will prove itself useful, because it does
not demand that a subscriber shall have gone to the expense of
installing a wire to his house and of paying a rent or fee for the use
of one.

The clock controlled by wireless telegraphy will doubtless undergo a
rapid development from the time when it is first introduced.
Practically the same principles which enable the electrician to
utilise the "Hertzian waves," or ether vibrations, for the purpose of
setting a clock right once a day, or once an hour, will permit of an
impulse, true to time, being sent from the central station every
second, or every minute, and when this has been accomplished it will
be seen that there is no more use for the maintenance of elaborate
clockworks at any place excepting the central station. The domestic
clock will, in fact, become mainly a "receiver" for the wireless
telegraphic apparatus, and its internal mechanism will be reduced,
perhaps, to a couple of wheels, which are necessary to transmit the
motion of a minute-hand to that which indicates the hours.

The fire-alarm of the future must be very simple and inexpensive in
order to ensure its introduction, not only into offices and warehouses
but also into shops and houses. The fire-insurance companies will very
shortly awake to the fact that prompt telegraphic alarm in case of
fire is worth far more than the majority of the prohibitions upon
which they are accustomed to insist by way of rendering fires less
likely. The main principles upon which the electric fire-alarm will be
operated have already been worked out and partially adopted. In the
system of fuses and cut-outs used in connection with electric
lighting, the methods of preventing fire due to the development of
excessive heat have been well studied. But simplification is
particularly required in the case of those fire-alarms which are to be
useful for giving intimation of a conflagration from any cause
arising.

As the telegraphic and telephonic wires are extended so as to traverse
practically all the streets of every city, the fire-insurance
companies will find it to their advantage to promote a simple plan,
depending on the use of a combustible thread passing round little
pulleys in the corners of all the rooms and finally out to the front,
where an electrical "contact-maker" is fixed, so that on the thread
being burnt and broken at any point in its circuit, an electric
message will be at once sent along the nearest wire to the
fire-brigade station and a bell set ringing both inside and outside
the premises.

Somewhat similar systems will be used for checking the enterprises of
the burglar. The best protected safes of the future will be enmeshed
in networks of wires encased in some material which will render it
impossible to determine their positions from the outside. These wires
will be so related to an electric circuit that the breaking of any
one of them, at any part of its course, will have the effect of
ringing a bell and giving warning at the police station, as well as at
other places where potential thief-catchers may be on hand. For doors
and windows very simple contact devices have already been brought out,
but the principal objection to their general adoption arises from the
fact that so very many houses remain unconnected with any telephone
system which may be made available for calling the police. Even were
all houses connected it is true that in some instances attempts might
be made to cut the wires when a raid was in contemplation, but the
risk of discovery in any such operation would prove a very powerful
deterrent. In fact the telephone wire, more than any other mechanical
device, is destined to aid in "improving" the burglar out of
existence.

With the indefinite multiplication of telephone subscribers at very
cheap rates, there will come a powerful inducement towards the
invention of new appliances for rendering the subscriber independent
of the attention of officers at any central exchange. The duty of
connecting an individual subscriber with any other with whom he may
desire to converse is, after all, a purely mechanical one, and
eminently of a kind which, by a combination of engineering and
electrical skill, may be quite successfully accomplished. In the
apparatus which will probably be in use during the twentieth century,
each subscriber will have a dial carrying on its face the names and
numbers of all those with whom he is in the habit of holding
communication. This will be his "smaller dial," and beside it will be
another, intended for only occasional use, through which, by
exercising a little more patience, he may connect himself with any
other subscriber whatever. Corresponding dials will be fixed in the
central office.

Under this system, when the subscriber desires to secure a connection,
he moves a handle round his dial until the pointer in its circuit
comes to the desired number. An electrical impulse is thus sent along
the wire to the central station for every number over which the
pointer passes, and the corresponding pointer or contact-maker at the
central station is moved exactly in sympathy. When the correct number
is reached the subscriber is in connection with the person with whom
he desires to converse. If, however, the latter should be already
engaged, a return impulse causes the bell of the first subscriber to
ring. Of course the prime cost of installing such a system as this
will be greater than in the case of the simple hand-connected
telephones; but the two systems can be used conjointly, and the
immense convenience, especially to large firms, of being able to go
straight to the parties with whom they wish to communicate, will
induce many of them to adopt the automatic apparatus as soon as it has
been perfected.

Wireless telephony must come to the front in the near future, but at
first for only very special purposes. The prospect of the profits that
would be attendant on working up a business unhampered by the heavy
capital charges which weigh upon the owners of telephone wires must
stimulate inventive enterprise to a remarkable degree in this
particular line. The main difficulty, however, in the application of
the system to general purposes will lie in the need for an ingenious
but simple means for enabling one subscriber to call another.

For this purpose probably the synchronised clock system already
referred to will be found essential, each office or house being
furnished with a timekeeper of this type kept in constant agreement
with a central clock, and so arranged that only when the ethereal
electrical impulse is given at a certain fixed point in the minute,
will any particular subscriber's bell be rung. This may be effected
by some such arrangement as a revolving drum, perforated at a
different part of its periphery for each individual subscriber, and
capable of permitting the electrical contact which makes a magnet and
rings the bell only at the fraction of a moment when the subscriber's
slot passes the pointer.

This will mean, of course, that only at a certain almost
infinitesimally small space of time in the duration of each minute
will it be possible to call any particular subscriber, or rather to
release the mechanism which will set his bell ringing for perhaps a
minute at a time. In the presence of unscrupulous competition,
resulting in the flinging out of Hertzian wave vibrations
promiscuously, for the purpose of destroying a rival's chances of
obtaining satisfactory connections, it would be necessary to make
rather more complicated arrangements of a nature analogous to those of
the puzzle lock. Instead of one impulse during the minute, two or
three would be required, in order to release the mechanism for ringing
any subscriber's bell; and no ring would take place unless the
time-spaces between these impulses were exactly in accordance with the
agreed form, which might be varied at convenient intervals.

Yet in the cases in which wireless telephony and telegraphy are taken
up by local public authorities having power to forbid any one playing
"dog in the manger," by preventing useful work by others while failing
to promote it himself, the simpler system of wireless telephone call
will be practicable. With the advance of municipalisation, and of
intelligent collectivism generally, enterprises of public utility will
be guarded from mere cut-throat commercial hostility much more
sedulously in the twentieth century than they have been in the past.

A great multitude of new applications of the telegraphic and
telephonic systems will be introduced in the immediate future. Not
only will those subscribers who are connected by wire with central
stations have the advantage of being called at any hour in the morning
according to their intimated wishes, but such services as lighting the
fires in winter mornings, so that rooms may be fairly warmed before
they are entered, will be performed by electric messages sent from a
central station.

Drawings will also be despatched by telegraph. For such purposes as
the transmission of sketches from the scene of any stirring event, the
first really practical application of drawing by telegraph will
probably depend upon the use of a large number of code words divided
into two groups, each of which, on the principles of co-ordinate
geometry, will indicate a different degree of distance from the base
line and from the side line respectively, so that from any sketch a
correct message in code may be made up and the drawing may be
reconstructed at the receiving end. Illustrated newspapers will in
this way obtain drawings exactly at the same time as their other
messages, and distant occurrences will be brought before the public
eye much more vividly and more correctly than has ever hitherto been
practicable.

For special objects, also, photographs can be sent by telegraph
through the use of the photo-relief in plaster of Paris, or other
suitable material, which travels backwards and forwards underneath a
pointer, the rising and falling of which is accurately represented by
thick and thin lines--or by the darker and lighter photographic
printing of a beam of light of varying intensity--at the other end, so
that a shaded reproduction of the photograph is produced. Relief at
the sending end is in this way translated into darkness of shade at
the receiving end. Any general expansion of this system, if it comes,
will necessarily be postponed till long after the full possibilities
of the codeword plan have been exploited, because the latter works in
exactly with the ordinary methods for sending telegraphic matter.

The keen competition between submarine and wireless telegraphy will be
one of the most exciting contests furnished by electrical progress in
the first quarter of the new century. Attention will be devoted to
those directions on the surface of the globe in which it is possible
to send messages almost entirely by land lines, and to bridge over
comparatively small intervals of space from land to land by wireless
telegraphy. Thus the Asiatic and Canadian route may be expected
shortly to enter into competition with the Atlantic cables in
telegraphic business to the United States; while Australia will be
reached _viâ_ Singapore and Java.

A great impetus will be given to the wireless system as a commercial
undertaking when arrangements have been perfected for causing the
receiver at any particular station to translate its message into a
form suitable for sending automatically. When this has been done, many
of the wayside stations will be almost entirely self-working, and
messages, indeed, may be despatched from island to island, or from one
floating station to another across the Atlantic itself.

Another requirement for really cheap telegraphy on the new system is
a more rapid method of making the letters or signals. The irregular
intervals at which the sparks from the coil of the transmitter fly
from one terminal to the other render it impossible to split up the
succession of flashes into intervals on the dot-and-dash principle,
without providing for each dot a much longer period of time than is
required for the transmission of messages on land lines. In fact the
need for going slowly in the sending of the message is the principal
stumbling-block which disconcerts ordinary telegraphic operators when
they come to try wireless telegraphy. For remedying this defect the
most hopeful outlook is in the direction of a multiplication of the
pieces of apparatus for spark-making and the combining of pairs of
them in such a way that, whenever the first one fails during an
appreciable interval of time to emit a spark, the second is called
into requisition. In this way a constant stream of sparks may be
ensured, without incurring the risk of running faster than the coil
will supply the electrical impulses necessary for the transmission of
the message.

Increased rapidity in land telegraphy by the ordinary system of
transmission by wire, and facility in making the records at the
receiving end in easily read typewriting--these are two desiderata
which at the close of the nineteenth century have been almost
attained, but which will take some time to introduce to general
notice. In the commercial system of the twentieth century the
merchant's clerk will write his messages on a typewriter which
perforates a strip of paper with holes corresponding to the various
letters, while it sets down in printing, on another strip, the letters
themselves. The latter will be kept as a record, but the former will
be taken to the telegraph office and put through the sending machine
without being read by the operator. The message will print itself at
the other end and wrap itself up in secret, nothing but the address
being made visible to the operator.

For the use of the general public who are not possessed of the special
apparatus necessary to perforate the paper another system is
available. Sets of movable type may be provided at the telegraph
office in small compartments, the letters being on one side and
indentations corresponding to the required perforations being cut or
stamped into the other sides of the movable pieces. The sender of a
message will set it up in a long shallow tray or "galley" like those
used by printers, and he will then turn the faces of the letters
downwards and see the whole passed through the machine without being
read by the operator; after which he can distribute the letters if he
chooses. In this way telegraphy will gradually become at once far more
secret and far cheaper than it is at present, and a large amount of
correspondence which at present passes through the post will be sent
along the wire.

Many merchants will have their telephonic apparatus fitted with
arrangements for setting up type or perforating strips of paper, as
already described; and also with receiving apparatus for making the
records in typewriting. If they fail to find a subscriber or
correspondent on hand at the time when he is wanted, they can write a
note to him which he will find hanging on a paper strip from his
telephone when he returns. Another mode of accomplishing a somewhat
similar result is to provide the telephone receiver itself with a
moving strip of steel, which, in its varying degrees of magnetisation,
records the spoken words so that they will, at some distance of time,
actuate the diaphragm of the receiver and emit spoken words. The
degree of permanency which can be attained by this system is, of
course, a vital point as regards its practical merits.

Still unsolved electrical problems are the making of a satisfactory
alternate current motor suitable for running with the kind of
currents generally used for electric lighting purposes--the
utilisation of the glow lamp having a partial vacuum or attenuated gas
for giving a cheap and soft light somewhat on the principle of the
Geissler tube--and last, but not least, the direct conversion of heat
into electricity.

With regard to the first-mentioned, the prospects have been materially
altered by a discovery announced at the New York meeting of the
American Association for the Advancement of Science within a few weeks
of the close of the nineteenth century. The handy and effective
alternate current motor indeed seemed then as far distant as it had
been in 1896, when Sir David Salomons remarked, in his work on
_Electric Light Installations_ (vol. ii., p. 97): "No satisfactory
alternate current motor available on all circuits exists as yet,
although," he added later, "the demand for such an appliance increases
daily". It seems, however, that electricians have been looking in the
wrong direction for the solution of using the same wire for alternate
current lighting and for motive power at the same time. Professor
Bedell, of Cornell University, announced at the New York meeting
referred to his discovery of the important fact that when direct and
alternate currents are sent over the same line each behaves as if the
other were not there, and thus the same line can be used for two
distinct systems of transmitting electrical energy. No time will be
lost in putting this announcement to the test, not only of scientific
but also of practical verification, and the probability is that all
electric lighting stations in the twentieth century will contain not
only dynamos of one type for the supply of light, but also direct
current generators for transmitting power in all directions over the
same cables.

The glow lamp having no carbon filament, but setting up a bright light
with only a fraction of the resistance presented by carbon, would, if
perfected, render electric lighting by far the cheapest as well as the
best method of illumination. Tentative work has indicated a high
degree of probability that success will be achieved, and the glowing
bulb is at any rate a possibility of the future which it will be well
to reckon with.

In reference to the conversion of heat into electricity without the
intervention of machinery to provide motion, and thus to cause
magnetic fields to cross one another, very little promise has yet been
shown of any fundamental principle upon which a practical apparatus of
the kind could be based. The electrician who works at this problem
has to begin almost _de novo_, and his task is an immensely difficult
one, although on every ground of analogy success certainly looks
possible. In the meantime, as has already been indicated, the steam
turbine and dynamo combined, working practically as a single machine
for the generation of electricity, offers practically the nearest
approach to direct conversion which is yet well in sight.




                              CHAPTER XI.

                               WARFARE.


The last notable war of the nineteenth century has falsified the
anticipations of nearly all the makers of small arms. The magazine
rifle was held to be so perfect in its trajectory, and in the rapidity
with which it could discharge its convenient store of cartridges in
succession, that the bayonet charge had been put outside of the region
of possibility in warfare. Those who reasoned thus were forgetting, to
a large extent, that while small arms have been improving so also has
artillery, and that a bayonet charge covered by a demoralising fire of
field-pieces, mortars, and quick-firing artillery is a very different
thing from one in which the assailants alone are the targets exposed
to fire. Given that two opposing armies are possessed of weapons of
about equal capacity for striking from a distance, they may do one
another a great deal of harm without coming to close quarters at all.
Yet victory will rest with the men who have sufficient bravery, skill
and ingenuity to cross the fire-zone and tackle their enemies hand to
hand.

Smoke-producing shells and other forms of projected cover, designed to
mask the advance of cavalry and infantry, will greatly assist in the
work of rendering this task of crossing the fire-zone less dangerous,
notwithstanding any possible improvement that may be effected in the
magazine-rifle. Already it has been observed that much of the surprise
and confusion which terrifies those who have no bayonets, when
subjected to a cannonade and at the same time brought face to face
with a bayonet charge, arises from the fact that they cannot see to
shoot straight, owing to the haze produced by the smoke and its
blinding effects upon the eyes.

Special smoke-producing shells, made for the express purpose of
covering a charge, will soon be evolved from the laboratory of the
chemist in pursuance of this clue. In addition to shells and other
missiles, small pieces of steel-piping will be projected by mortars
into the fire-swept zone, in order to supplement the defects of
natural cover which, of course, are nearly always as great as
possible, seeing that the ground has generally been selected by the
side against which the attack is being directed.

The task of enabling a rifleman to shoot straight has been taken up
with extraordinary zeal and ability compared with the amount of skill
and effort devoted to the corresponding or opposing object of spoiling
his aim and preventing him from getting a shot in. When this latter
has been to some extent accomplished, mainly by the agency of
artillery, the bayonet and other weapons for use at close quarters
will once more be in the ascendant. Thin shields of hard steel will be
affixed to the rifles of the attacking party, so as to deflect the
bullets wherever possible.

This baffling of the rifleman by the artillery supporting the cavalry
and bayonet charge will produce momentous changes, not only in the
future of war, but also in that of international relations. Anything
which tends to discount the value of personal bravery and to elevate
the tactics of the ambuscade and the sharp-shooting expedition gives,
_pro tanto_, an advantage to the meaner-spirited races of mankind, and
places them more or less in a position of mastery over those who hold
higher racial traditions. The man who will face the risk of being shot
in the open generally belongs to a higher type of humanity than he who
only shoots from behind cover.

Moreover, the nations which have the skill and ingenuity to
manufacture new weapons of self-defence belong to a higher class than
those which only acquire advanced warlike munitions by purchase. One
of the early international movements of the twentieth century will be
directed towards the prohibition of the sale of such weapons as
magazine-rifles, quick-firing field guns, and torpedoes to any savage
or barbarous race. It will be accounted as treason to civilisation for
any member of the international family to permit its manufacturers to
sell the latest patterns of weapons to races whose ascendency might
possibly become a menace to civilisation. As factors in determining
the survival of the fittest, the elements of high character, bravery,
and intellectual development must be conserved in their maximum
efficiency at all hazards.

Another potent element in the safeguards of civilisation may be seen
in the increased effectiveness of weapons for coastal defence. The
hideous nightmare of a barbarian irruption, such as those which almost
erased culture and intellect from the face of Europe during the dark
ages of the fourth, fifth and sixth centuries, may occasionally be
seen exercising its influence in the pessimistic writings which are
from time to time issued from the Press predicting the coming
ascendency of the yellow man.

However the case may be in regard to nations which are accessible by
land to the encroachments of the Asiatic, there is no doubt that those
countries which are divided off by the sea have been rendered much
more secure through the rapid advances which have been made in the
modern appliances for defending coasts and harbours. In naval tactics,
also, it will be more and more clearly seen that to possess and defend
the harbours where coaling can be carried out is practically to
possess and defend the trade of the high seas; and the essence of good
maritime policy will be to so locate the defended harbours that they
may afford the greatest amount of protection, having in view the harm
that may be done by an enemy's harbours in the vicinity.

The most effective naval weapon in the future will undoubtedly be the
torpedo, but, like the bayonet, it requires to be in the hands of
brave men before its value as the ultimate arbiter of naval conflict
can be demonstrated. Much fallacious teaching has arisen from what has
been called the lessons of certain naval wars which occurred on the
coasts of South America and China--international embroilments in which
mercenaries, or only half-trained seamen and engineers, were engaged.
On similar fallacious grounds it was argued that the magazine-rifle
had put the bayonet out of the court of military arbitrament, and the
South African war has proved conclusively how erroneous was that idea.
The use of the torpedo-boat and of the weapons which it carries must
always demand, like that of the bayonet, men of the strongest nerve,
and of the greatest devotion to their duty and to their country.

Fifty miles an hour is a rate which is already in sight as the speed
of the future torpedo-boat, the first turbine steamer of the British
Navy having achieved forty-three miles an hour before the end of the
nineteenth century. It should be distinctly understood, however, that
such a speed cannot be kept up for any great length of time and that
long voyages are out of the question. The rôle of the turbine
torpedo-boat will be to "get home" with its weapon in the shortest
practicable time. Hence its great value for the defence of harbours by
striking at distances of perhaps two or three hours' steaming.

On the high seas the battle-ships, which will virtually be the
cruisers of the future, will be provided with turbine torpedo-boats,
carried slung in convenient positions and ready at short notice to be
let slip like greyhounds. During the hazardous run of the
torpedo-boat towards the enemy, various devices will be employed for
the purpose of baffling his aim, such for instance as the emission of
volumes of smoke from the bows and the erection of broad network
blinds covering the sight of the little craft, but capable of being
shifted from side to side, so that the enemy's marksmen may never know
exactly what part of the object in sight is to be aimed at. The
torpedo will be carried on a mast, which at the right moment can be
lowered to form a projecting spar like a bowsprit; and the explosion
that will take place on its impact with the enemy's hull will be
enough to blow a fatal breach in any warship afloat.

For harbour defence and the safety of the battle-ship the wire-guided
and propelled torpedo will form a second line behind the fast
torpedo-boat. This type of weapon strikes with more unerring accuracy
than any other yet included in the armoury of naval warfare, because
it is under the control of the marksman from the time of its launching
until it fulfils its deadly mission. Its range, of course, is strictly
limited; but it may be worked to advantage within the distances at
which the best naval artillery can be depended upon to make good
practice.

The least costly and the lightest form is that in which the backward
pulling of two wires, unwinding two drums on the torpedo, actuates two
screws at greater or less speeds according to the rapidity of the
motion imparted, any advantage of speed in one screw over the other
being responded to by an alteration in the direction taken by the
weapon. The torpedo may be set so as to dive from the surface at any
desired interval; but, of course, an appearance in the form of at
least a flash is necessary to enable the operator to judge in what
direction he is sending his missile. Small torpedo-boats, not manned
but sticking to the surface, may be used in the same manner. Each one
no doubt runs a very great risk of being hit by shot or shell aimed at
them; but out of half a dozen, discharged at short intervals, it would
be practically impossible for an enemy to make certain that one at
least did not find its billet.

The submarine boat will have some useful applications in peace; but
its range of utility in warfare is likely to be very limited. It is
hopeless to expect the eyes of sailors to see any great distance under
the water; therefore the descent must be made within sight of the
enemy, who has only to surround himself with placed contact-torpedoes
hanging to a depth, and to pollute the water in order to render the
assault an absolutely desperate enterprise.

Military aeronautics, like submarine operations in naval warfare, have
been somewhat overrated. Visions of air-ships hovering over a doomed
city and devastating it with missiles dropped from above are mere
fairy tales. Indeed the whole subject of aeronautics as an element in
future human progress has excited far more attention than its
intrinsic merits deserve.

A balloon is at the mercy of the wind and must remain so, while a true
flying machine, which supports itself in the air by the operation of
fans or similar devices, may be interesting as a toy, but cannot have
much economical importance for the future. When man has the solid
earth upon which to conduct his traffic, without the necessity of
overcoming the force of gravitation by costly power, he would be
foolish in the extreme to attempt to abandon the advantage which this
gives him, and to commit himself to such an element as the air, in
which the power required to lift himself and his goods would be
immeasurably greater than that needed to transport them from place to
place.

The amount of misdirected ingenuity that has been expended on these
two problems of submarine and aerial navigation during the nineteenth
century will offer one of the most curious and interesting studies to
the future historian of technological progress. Unfortunately that
faculty of the constructive imagination upon which inventive talent
depends may too frequently be indulged by its possessor without any
serious reference to the question of utility. Fancy paints a picture
in which the inventor appears disporting himself at unheard-of depths
below the surface of the sea or at extraordinary heights above the
level of the land, while his friends, his rivals, and all manner of
men and women besides, gaze with amazement! Patent agents are only too
well aware how often an inordinate desire for self-glorification goes
along with real inventive talent, and how many of the brotherhood of
inventors make light of the losses which may be inflicted upon
trusting investors so long as they themselves may get well talked
about.

Nations may at times be infected with this unpractical vainglory of
inventiveness; and on these occasions there is need of all the
restraining influence of the hard-headed business man to prevent the
waste of enormous sums of money. The idea that military ascendency in
the future is to be secured by the ability to fly through the air and
to dive for long distances under the water has taken possession of
certain sections in France, Germany, Russia, Great Britain and the
United States. Large numbers of voluble "Boulevardiers" in Paris have,
during the last years of the nineteenth century, made it an article of
their patriotic faith that the future success of the French navy
depends upon the submarine boat. The question as to what an enemy
would do with such a boat in actual warfare seems hardly ever to occur
to them; and, indeed, any one who should venture to put such a query
would run the risk of being set down as a traitor to his country!

More important to the student of the practical details of naval
preparation is the great question as to the point at which the contest
between shot and armour will be brought to a standstill. That it
cannot proceed indefinitely may be confidently taken for granted. The
plate-makers thicken their armour while the gun-makers enlarge the
size and increase the penetrative power of their weapons, until the
weight that has to be carried on a battle-ship renders the attainment
of speed practically impossible.

Meanwhile there is going forward, in the hull of the vessel itself, a
gradual course of evolution which will eventually place the policy of
increasing strength of armour and of guns at a discount. The division
of the air-space of a warship into water-tight compartments will
doubtless prove to be, in actual naval conflict, a more effectual
means of keeping the vessel afloat than the indefinite increase in the
thickness and consequent weight of her armour.

The most advanced naval architects of modern times are bestowing more
and more attention upon this feature, as affording a prospect of
rendering ships unsinkable, whether through accidents or through
injury in warfare. No doubt, for merchant steamers, it will be seen
that development along the lines already laid down in this department
will suffice for all practical purposes. The water-tight bulkheads,
with readily closed or automatically shutting doorways, ensure the
maintenance of buoyancy in case of any ordinary accident from
collision or grounding, while the duplication of engines, shafts and
propellers--without which no steamship of the middle twentieth century
will be passed by marine surveyors as fit for carrying passengers on
long ocean voyages--will make provision against all excepting the most
extremely improbable mishaps to the machinery.

If the numerical estimate of the chance of the disablement of a single
engine and its propeller during a certain voyage be stated at one to
a thousand, then the risk of helplessness through the break down of
both systems in a vessel having twin screws and entirely separate
engines will be represented by the proportion of one to a million.
This mode of reckoning, of course, assumes that the two systems could
be made absolutely independent in relation to all possible disasters;
and some deduction must be made on account of the impossibility of
attaining this ideal. Yet it is evident that when every practicable
device has been adopted for rendering a double accident improbable the
chances against such a disaster will not be far from the proportion
stated.

When we come to consider the evolution of the warship as compared with
that of the merchant steamer, we are at once confronted with the fact
that the infliction of injury upon the boilers, the engine, or the
propellers of a hostile vessel is the great object aimed at by the
gunners. The evolution of the warship in the direction of ensuring
safety, therefore, will not stop at the duplication of the engines,
boilers and propellers. In fact it must sooner or later be apparent
that the interests of a great naval power demand the working out of a
type of warlike craft that shall be almost entirely destitute of
armour, but constructed on such a principle--both as to hull and
machinery--that she can be raked fore and aft, and shot through in all
directions without becoming either water-logged or deprived of her
motive power.

A torpedo-boat built on this system may consist essentially of a
series of steel tubes of large section grouped longitudinally, and
divided into compartments like those of a bamboo cane. Each of these
has its own small but powerful boilers and engines, and each its
separate propeller at the stern. Care also is taken to place the
machinery of each tube in such a position that no two are abreast. In
fact, the principle of construction is such as to render just as
remote as may be the possibility of any shot passing through the
vessel and disabling two at the same time.

If a boat of this description has each tube furnished not only with a
separate screw at the stern, but also with a torpedo at the bows, it
can offer a most serious menace to even the most powerful battle-ship
afloat, because its power of "getting home" with a missile depends not
upon its protective precautions, but upon an appeal to the law of
averages, which makes it practically impossible for any gunners,
however skilful, to disable all its independent sections during the
run from long range to torpedo-striking distance. The attacked
warship is like an animal exposed to the onslaught of one of those
fabled reptiles possessing a separate life and a separate sting in
each of its myriad sections; so that what would be a mortal injury to
a creature having its vital organs concentrated in one spot produces
only the most limited effect in diminishing its strength and powers of
offence.

Or this class of naval fighter may be regarded as a combined fleet of
small torpedo-boats, bound together for mutual purposes of offence and
defence. Singly, they would present defects of coal-carrying capacity,
sea-going qualities, and accommodation for crew which would render
them comparatively helpless and innocuous; but in combination they
possess all the travelling capacities of a large warship, conjoined
with the deadly powers at close quarters of a number of torpedo boats,
all acting closely in concert upon a single plan.

The chief naval lesson taught during the Spanish-American War was the
need for improving the sea-going qualities of the torpedo-boat before
it can be regarded as a truly effective weapon in naval warfare. It
was announced at one stage that if the Spanish torpedo-boat fleet
could have been coaled and re-coaled at the Azores, and two or three
other points on the passage across to America, it might have been
brought within striking distance of the United States cruisers
operating against Santiago. This hypothetical statement provided but
cold comfort for the Spaniards, who had been persuaded to put so much
of their available naval strength into a type of craft utterly
unsuited for operations complying with the first great requirement of
naval warfare, namely, that the proper limit of the campaign coincides
with the shores of the enemy's country.

But when the naval architect and the engineer have evolved a class of
torpedo-using vessel which can both travel far and strike hard, and
which, moreover, can stand a few well-directed shots penetrating her
without succumbing to their effect, a new era will have been opened up
in naval warfare--an era of high explosive weapons requiring to strike
home with dash and bravery in spite of risk from shot and shell; but,
like the bayonet on land, capable of overthrowing all war-machines
which can only strike from a considerable distance.




                             CHAPTER XII.

                                MUSIC.


A perfect _sostenuto_ piano has been the dream of many a musician
whose ardent desire it was to perform his music exactly as it was
written. A sustained piano note is, indeed, the great mechanical
desideratum for the music of the future. In music, as at present
written and published for the piano, which is, and must continue to
be, the real "King of Instruments," there is a good deal of
make-believe. A long note--or two notes tied in a certain method--is
intended to be played as a continued sound, like the note of an organ;
whereas there is no piano in existence which will produce anything
even approximately approaching to that effect. The characteristic of
the piano as an instrument is _percussion_, producing, at the moment
of striking the note, a loud sound which almost immediately dies away
and leaves but a faint vibration.

The phonographic record of a pianoforte solo shows this very clearly
to the eye, because the impression made by a long note is a
deeply-marked indentation succeeded by the merest shallow
scratch--not unlike the impression made by a tadpole on mud--with a
big head and an attenuated body. Every note marked long in pianoforte
music is therefore essentially a _sforzando_ followed by a rapid
_diminuendo_. Anything in such music marked as a long note to be
sustained _crescendo_--the most thrilling effect of orchestral,
choral, and organ music--is necessarily a sham and a delusion.

The genius and skill which have enabled the masters of pianoforte
composition not only to cover up this defect in their instrument, but
even to make amends for it, by working out effects only suitable for a
percussion note, present one of the most remarkable features of
musical progress in the nineteenth century. So notable is that fact in
its relation to the pianoforte accompaniments of vocal music, that it
seems open to question whether, even in the presence of a thoroughly
satisfactory _sostenuto_ piano, much use would for many years be made
of it for this particular purpose. The effects of repeated notes
succeeding one another with increasing or decreasing force, and of
_arpeggio_ passages, have been so fully explored and made available in
standard music of every grade, that necessarily the public taste has
set itself to appreciate the pianoforte solo and the accompanied song
exactly as they are written and performed. These are, after all, the
highest forms of music which civilisation has yet enabled one or two
performers to produce.

Yet, in regard to solo instrumentalisation, there is no doubt that a
general hope exists for the discovery of a compromise between the
piano and the organ or between the piano and the string band. Some
inventors have aimed in the latter direction and others in the former;
but no one has succeeded in really recommending his ideas to the
public. Combined piano-violins and piano-organs have been shown at
each of the great Exhibitions from the middle of the nineteenth
century to its close. Several of these instruments have been devised
and constructed with great ingenuity; and yet practically all of them
have been received by the musical profession either with indifference
or with positive ridicule.

The fact is that revolutionary sudden changes in musical instruments
are rendered impossible owing to the near relationship which exists
between each instrument and the general body of the music that is
written for it. No one can divorce the two, which, as a factor in
æsthetic progress, are really one and indivisible. Therefore, if any
man invents a musical instrument which requires for its success the
sudden evolution of a new race of composers writing for it, and a new
type of educated public taste to hail these composers with delight, he
is asking for a miracle and he will be disappointed.

What is wanted is not a new instrument, but an improved piano that
shall at one and the same time correct, to some extent, the defects of
the existing instrument, and leave still available all the brilliant
effects which have been invented for it by a generation of musical
geniuses. We want the sustained note, and yet we do not wish to lose
the pretty turns and graceful devices by which the lack of it has been
hidden, or atoned for, in the works of the masters. Therefore our
sustained note must not be too aggressive. For a long time, indeed, it
must partake of the very defects which it is intended ultimately to
abolish.

In other words, we want to retain the percussion note with the dampers
and with the loud and soft pedals, in fact, all the existing
inventions for coaxing some of the notes to sustain themselves while
others are cut short, as may be desired, and at the same time we have
to add other and more effective means to assist the performer in
achieving the same object.

The more or less complicated methods aiming at the prolongation of the
residual effect of the percussion have apparently been very nearly
exhausted. Some of the most modern pianos are really marvels of
mechanical ingenuity applied to this purpose. We have now to look to
something slightly resembling the principle of the violin or of the
organ, in order to secure the additional _sostenuto_ effect for which
we are searching. Having to deal with a piano in practically its
existing form, we obviously require to take special account of the
fact that the note is begun by percussion, and that any attempt to
bring a solid substance into contact with the wire while still
vibrating, with the object of continuing its motion, is likely to
produce more or less of a jarring effect.

The air-blast type of note-continuer for _sostenuto_ effect therefore
offers the most promising outlook for the improvement of the modern
piano in the direction indicated. By directing a blast of air from a
very thin nozzle on to the vibrating wire of a piano, the sound
emitted may be very greatly intensified; and although naturally the
decreasing amplitude of the vibration may in itself tend to create a
_diminuendo_, yet it is possible to make up for this in some degree
by causing the air-blast to increase in force, through the use of any
suitable means, modified by an extra pedal as may be desired.

Delicate _pianissimo_ effects, somewhat resembling those of the Eolian
lyre, are produced by playing the notes with the air-blast alone,
without the aid of percussion. But the louder _sostenuto_ notes depend
upon the added atmospheric resistance offered by a strong current of
air to those movements of the wire which have been originally set up
by percussion, and the fact that this resistance gives rise to a
corresponding continuance of the motion. The prolongation of a note in
this way is analogous to the continual swinging of an elastic switch
in a stream of water, the current by its force producing a rhythmic
movement.

When these Eolian effects, as applied to the pianoforte, have been
carefully studied, many devices for controlling them will be brought
forward. The main purpose, however, must be to connect the air-blast
with the percussion apparatus in such a manner that, as soon as a key
is depressed, the nozzle of that particular note in the air-blast is
opened exactly at the same time that the wire is struck by the hammer,
and it remains open as long as the note is held down. The movement of
an extra pedal, however, has the effect of throwing the whole of the
air-blast apparatus out of gear and reducing the piano to a percussion
instrument, pure and simple.

It will be on the concert platform, no doubt, that this kind of
improvement will find its first field of usefulness. Performers will
require, in addition to their grand pianos, reservoirs of compressed
air attachable by tubes to their instruments. In private houses
hydraulic air-compressors will be found more convenient. When the
piano has by some such means acquired the faculty of _singing_ its
notes, as well as of _ringing_ them, its ascendency, as the finest
instrument adapted to solo instrumentalism, will be assured.

The common domestic piano is rightly regarded by many people as being
little better than an instrument of torture. One reason for this
aversion is that, in the great majority of cases, the household
instrument is not kept in tune. Probably it is not too much to say
that the man who would invent a sound cottage piano which would remain
in tune would do more for the improvement of the national taste in
music than the largest and finest orchestra ever assembled. The
constantly vitiated sense of hearing, which is brought about by the
continual jangle of notes just a fractional part of a tone out of
tune, is responsible for much of the distaste for good music which
prevails among the people. When the domestic instrument is but
imperfectly tuned, it is natural that those pieces should be preferred
which suffer least by reason of the imperfection, and these, it need
hardly be remarked, generally belong to the class of music which must
be rated as essentially inferior, if not vulgar.

The device of winding a string round a peg and twisting it up on the
latter in order to obtain tension for a vibrating note is thousands of
years old. It was the method by which tension was imparted to some of
the earliest harps and lyres of which history is cognisant; and it is
still to be found to-day in the most elaborate and costly grand piano,
with but few alterations affecting its principle of action. The
pianoforte of the future will be kept in tune by more exact and
scientific methods, attaining a certain balance between the thickness
of the wire and the tension placed upon it by means of springs and
weights.

Besides the ravages of the badly-tuned piano, much suffering is
inflicted by the barbarous habit of permitting a sounding instrument
to be used for mere mechanical exercises. The taste of the pupil is
vitiated, and the nerves of other inmates of the house are subjected
to a source of constant irritation when long series of notes,
arranged merely as muscular exercises, and some of them violating
almost every rule of musical form, are ground out hour after hour like
coffee from a coffee-mill. The inconsistency of subjecting the musical
ear and taste of a boy or girl to this process, and then expecting the
child to develop an innate taste for the delicacies of form in melody
and of the beauty of harmony, is almost as bad as would be that of
asking a Chinese victim of foot-binding to walk easily and gracefully.

The use of the digitorium for promoting the mechanical portion of a
musical education by the training of the fingers has already, to some
slight extent, obviated the evils complained of. But this instrument
is, as yet, only in its rudimentary stage of development. The dumb
notes of the keyboard ought to be capable of emitting sounds by way of
notice to the operator, in order to show when the rules have been
broken. Thus, for instance, the impact caused by putting a key down
should have the effect of driving a small weight upwards in the
direction of a metal bar, the distance of which can be adjusted.
Another bar, at a lower level, is also approached by a second weight,
and the perfect degree of evenness in the touch is indicated by the
fact that the lower bar should be made to emit a faint sound with
every note, but the higher one not at all. The closer the bars the
more difficult is the exercise, and remarkable evenness of touch can
be acquired by a progressive training with such an instrument.

The organ has been wonderfully improved during the nineteenth century.
Yet the decline of its popularity in comparison with the pianoforte
may be accounted for on very rational grounds. While ardent organists
still claim that the organ is the "King of Instruments" the public
generally entertain a feeling that it is a deposed king. It remains
for the organ-builders of the twentieth century to attack the problem
of curing its defects by methods going more directly to the root of
the difficulty than any hitherto attempted.

As contrasted with the pianoforte, the organ is extremely deficient in
that power which the conductor of an orchestra loves to
exercise--facility in accentuating and in subduing at will the work of
each individual performer. For all practical purposes the ten fingers
of a piano-player are the ten players in an orchestra; and, according
to the force with which each finger strikes the note, is the
prominence given to its effects. An air or a _motif_ may be brought
out with emphasis by one set of fingers, while the others are playing
an accompaniment with all sorts of delicate gradations of softness and
emphasis.

By multiplying the manuals, the organ-builder has endeavoured, with a
certain degree of success, to make up for the unfortunate fact that
the performer on his instrument possesses no similar facility in
making it speak louder when he submits the note to extra pressure. One
hand may be playing an air on one manual, while the second is engaged
in the accompaniment on another; and the former may be connected with
a louder stop, or with one of a more penetrating quality than the
latter.

This device, together with an elaborate arrangement of swells and
pedal-notes, has greatly enlarged the capacity of the organ for
producing those choral effects which mainly depend upon gradations of
volume. Yet the whole system, elaborate as it is, offers but a poor
substitute for the marvellous range of individuality that may be
expressed on the notes of the piano by instantaneous changes in the
values ascribed to single notes. By the same action of his finger the
pianist not only makes the note, but also gives its value; while the
method of the organist is to neglect the element of finger-pressure
and to rely upon other methods for imparting emphasis or softness to
his work.

An organ that shall emit a louder or softer note, according to the
force with which the key on the manual is depressed, will no doubt be
one of the musical instruments of the twentieth century. Whether each
key will be fitted with a resisting spring, or whether the lever will
be constructed in such a way as to throw a weight to a higher or lower
grade of position, according to the force with which it is struck, is
a question which will depend upon the results of experiment. But the
latter method is more in consonance with the conditions which have
given to the piano its wonderful versatility, and it therefore seems
the more probable solution of the two. Upon the vigour of the finger's
impact will depend the height to which a valve is thrown, and this
will determine the speed and volume of the air which is liberated to
rush into the pipe and make the note.

The nineteenth century orchestra is a fearfully and wonderfully
constructed agglomeration of ancient and modern instruments. Its
merits are attested by the fine musical sense of the most experienced
conductors, whose aim it has been so to balance the different
instruments as to produce a tastefully-blended effect, while at the
same time providing for solos and also for the rendering of parts in
which a small number of performers may contribute to the unfolding of
the composer's ideas. The orchestra cannot therefore be examined or
discussed from a mechanical point of view, however much some of the
instruments of which it is composed may be thought capable of
improvement.

But the position of the conductor himself in the front of an orchestra
is, from a purely artistic standpoint, highly anomalous. It is as if
the prompter at the performance of a drama were to be seen taking the
most conspicuous part and mixing among the actors upon the stage. If
an orchestral piece be well played without the visible presence of a
conductor, the sense of correct time reaches the audience naturally
through the music itself; and any sort of gesticulations intended to
mark it are under these conditions regarded as being out of place.

The foremost orchestral conductors of the day are evidently impressed
with this unfitness of the mechanical marking of time by the wild
waving of a stick or swaying of the body; and accordingly, however
much they exert themselves at the rehearsal, they purposely subdue
their motions during a public performance. The time is not far
distant when the object of the conductor will be to guide his band
without permitting his promptings to be perceived in any way by the
audience.

For this purpose an "electric beat-indicator" will prove useful.
Various proposals for its application have been put forward, and for
different purposes several of them are obviously feasible. For
instance, in one system the conductor sits in a place hidden from the
audience and beats time on an electric contact-maker, which admits of
his sending a special message to any particular performer whenever he
desires to do so. The signal which marks the time may be given to each
performer, either visually by a beater concealed within a small
bell-shaped cavity affixed to his desk or to his electric light; or it
may be conveyed by the sense of touch through a mechanical beater
within a small metal weight placed on the floor and upon which he sets
one of his feet.

The electric time-beater in the latter system thus taps the measure
gently on the sole of the performer's foot, and special signals, as
may be arranged, are sent to him by preconcerted combinations of taps.
The absence of any distraction from the music itself will soon be
gratefully felt by audiences, and the playing of a symphony in the
twentieth century, in which the whole orchestra moves sympathetically
in obedience to the "nerve-waves" of the electric current, will be the
highest possible presentment of the musical art.




                            CHAPTER XIII.

                            ART AND NEWS.


The production of pictures for the million will be practically the
highest achievement of the graphic art in the twentieth century. Many
eminent painters do not at all relish the prospect, being strongly of
opinion that when every branch of art becomes popular it will be
vulgarised. This notion arises from a fallacy which has affected ideas
during the nineteenth century in many matters besides art, the mistake
of supposing that vulgar people all belong to one grade of society.

Yet every one who knows modern England, for instance, is perfectly
aware that the highest standard of taste is only to be found in the
elect of all classes of society. After the experience of the
eighteenth century, surely it ought to have been recognised that the
"upper ten thousand," when left to develop vulgarity in its true
essence, can attain to a degree of perfection hardly possible in any
other social grade. Is there in the whole range of pictorial art
anything more irredeemably vulgar than a "State Portrait" by Sir
Thomas Lawrence or one of his imitators?

It was under the prompting of a dread of the process of popularising
art that so many eminent painters of the nineteenth century protested
against the fashion set by Sir J. E. Millais when he sold such
pictures as "Cherry Ripe" and "Bubbles," knowing they were intended
for reproduction in very large numbers by mechanical means. From a
somewhat similar motive a few of the leading artists of the nineteenth
century for a time stood aloof from the movement for familiarising the
people with at least the form, if not the colouring, of each notable
picture of the year. From small and very unpretentious beginnings, the
published pictorial notes of the Royal Academy and other exhibitions
of the year have risen to most imposing proportions; and already there
is some talk of attempting a few of the best from each year's
production in colours.

Half-tone zinco and similar processes have brought down the expenses
entailed by reproductions in colour-work, so as to render an
undertaking of this kind much more feasible than it was in the middle
of the last half-century. "Cherry Ripe" cost five thousand pounds to
reproduce, by the laborious processes of printing not only each
colour, but almost every different shade of each colour from a
different surface.

In the "three-colour-zinco" process of reproduction only three
printings are required, each colour with all its delicate gradations
of shade being fully provided for by a single engraved block. When
machines of great precision have been finally perfected for admitting
of the successive blocks being printed from on paper run from the reel
without any handling, a revolution will be brought about not only in
artistic printing, but even in the conditions of studio work upon
which the artist depends for success.

First, the pictorial notes of the year will be brought out in colour;
and as competition for the right of reproduction increases, the
artists who have painted the most suitable and most popular pictures
will find that they can get more remuneration for copyright than they
can for the pictures themselves. This has already been the case in
regard to a very limited number of pictures; but the exception of the
past will be the rule of the future, at least as regards those
pictures which possess any special merits at all.

More thought will therefore be required as the motive or basis of each
subject; and historical pictures will come more into favour, the
affected simplicity and mental emptiness of the _plein air_ school
being discarded in favour of a style which shall speak more directly
to the people, and stir more deeply both their mental and their
emotional natures.

The artist and the printer must then confer. They can no longer afford
to work in the future with such disregard of each other's ideas and
methods as they have done in the past. It was at one time the custom
among painters almost to despise the "black-and-white man" who drew
for the Press in any shape or form; but that piece of affectation has
nearly been destroyed by the general ridicule with which it is now
received, and by the knowledge that there are already, at the end of
the nineteenth century, just as many men of talent working by methods
suitable for reproduction, as there are painters who confine their
attention to palette, canvas and brush.

The printer will now advance a step further, and will invoke the
services of the painter himself, even prescribing certain methods by
which the Press may be enabled to reproduce the work of the artist
more faithfully than would otherwise be possible.

Transparency painting will no doubt be one of these methods. The
artist will paint on a set of sheets of transparent celluloid or
glass, mounted in frames of wood and hinged so that they can, for
purposes of observation, be put aside and yet brought back to their
original positions quite accurately. Each different transparent sheet
will be intended for one pure colour, the only pigments used being of
the most transparent description obtainable.

The picture may thus be built up by successive additions and
alterations, not all put upon one surface, but constituting a number
of "monochromes," superimposed one upon the other. When finished, each
of these one-colour transparencies can then be reproduced by
photo-mechanical means for multi-colour printing in the press.

By what are known as the photographic "interruption" processes, a kind
of converse method has achieved a certain degree of success. A
landscape or a picture is photographed several times from exactly the
same position, but on each occasion it is taken through a screen of a
different coloured glass, which is intended for the purpose of
intercepting all the rays of light, except those of one particular
tint. Coloured prints in transparent gelatine or other suitable medium
are then made from the various negatives, each in its appropriate
tint; and when all are placed together and viewed through transmitted
light, the effect of the picture, with all its colours combined, is
fairly well produced. More serviceable from the artistic point of view
will be the method according to which the artist makes his picture by
transmitted light, but the finished printed product is seen on paper,
because this latter lends itself to the finest work of the artistic
printer.

The principal branch of the work of the photographer must continue to
be portraiture. He cannot greatly reduce the cost of getting a really
good negative, because so much hand-labour is required for the task of
"retouching"; but he can give, perhaps, a hundred prints for the price
which he now charges for a dozen, and make money by the enterprise. It
has already been proved that there is no necessity for using expensive
salts of gold, silver or platinum in order to secure the most artistic
prints; and, as a matter of fact, some of the finest art work in the
photography of the past quarter of a century has been accomplished
with the cheapest of materials, such as gelatine, glue and lampblack.

Pigmented gelatine is, without doubt, the coming medium for
photographic prints, and the methods of making them must approximate
more and more closely to those of the typographic printer. By
producing a "photo-relief" in gelatine--sensitised with bichromate of
potash, and afterwards exposed first to the sun and then to the action
of water--an impression in plastic material can be secured, from
which, with the use of warm, thin, pigmented gelatine, a hundred
copies or more can be printed off in a few minutes.

The very general introduction of such a process has naturally been
delayed owing to the extra trouble involved in the first methods which
were suggested for applying it, and also, no doubt, on account of the
recent fashion for platinotype and bromide of silver prints. But as
soon as more convenient details for the making of pigmented gelatine
prints have been elaborated, the cheapness of the material and the
wonderful variety of the art shades and tints in which photographs can
be executed will give the gelatine processes an advantage in the
competition which it will be hopeless for other methods to challenge.

The daily newspapers of a few years hence will be vividly illustrated
with photographic pictures of the personages and the events of the
day. The gelatine photo-relief, already alluded to, will no doubt
afford the basis of the principal processes by which this will be
effected. Hitherto the chief drawback has been the difficulty of
imparting a suitable grain to the printing blocks made from these
reliefs; but this has been practically overcome by the use of sheets
of metallic foil previously impressed with the form of a
finely-engraved tint-block. The actual printing surface, of course,
consists of an electrotype or stereotype taken from this
metallic-grained photographic face.

For "high-art" printing on fine paper with the more expensive kinds of
ink, the half-tone zinco processes will doubtless maintain their
supremacy and gradually diminish the area within which lithographic
printing is required. In the case of newspaper work, however, where
haste in getting ready for the press is necessarily the prime
consideration, the flat and very slightly-indented surface of the
zinco block is found to be unsuited to the requirements. Flat blocks,
which require careful "overlaying" on the machine, waste too much time
for daily news work. Without going into technical details it may be
surmised in general terms that in the near future almost every
newspaper will contain, each day, one or more photo-illustrations of
events of the previous day or of the news which has come to hand from
a distance.

Type-setting by hand is, for newspaper purposes, being so rapidly
superseded, that only in the smaller towns and villages can it remain
for even a few years longer. But in the machines by which this
revolution has been effected, finality has been by no means reached.
Every line of matter which appears in any modern daily newspaper has
to pass through two processes of stereotyping before it makes a
beginning to effect its final work of printing upon paper.

First, there is the stereotyping or casting of the line in its
position in the type-setting machine after the matrices have been
ranged in position by the application of the fingers to the various
keys; and, secondly, when all the lines have been placed together to
make a page, it is necessary to take an impression of them upon
_papier mâché_, or what is technically called "flong," and then to dry
it and make the full cast from it curved and ready for placing on the
cylinder of the printing machine. The delay occasioned by the need for
drying the wet flong is such a serious matter--particularly to evening
newspapers requiring many editions during the afternoon--that several
dry methods have been tried with greater or less success.

But there is really no need for more than one casting process. In the
twentieth century machine the matrices will be replaced by permanent
type from which, when ranged in the line, an impression will be made
by hard pressure on a small bar of soft metal or plastic material. All
the impressed bars having been set together in a casting box having
the necessary curvature, the final stereo plate for printing from will
be taken at once by pouring melted metal on the combined bars.

An appreciable saving, both in time and in money, will also be
effected by applying the principle of the perforated strip of paper or
cardboard to the purpose of operating the machine by which the
necessary letters are caused to range themselves in the required
order. Machines similar to typewriters will be employed for
perforating the strips of paper and for printing, at the same time, in
ordinary letters the matter just as if it were being typewritten.

The corrections can then be made by cutting off those pieces of the
strips which are wrong and inserting corrected pieces in their places.
No initial "justification" to the space required to make a line is
needed in this system. The strips, however, are put through the
setting machine, and, as they make the reading matter by the
impression of bars as already described, they are divided into lines
automatically.

Large numbers of newspapers will in future be sold from
"penny-in-the-slot" machines. The system to be adopted for this
particular purpose will doubtless differ in some important respects
from that which has been successful in the vending of small articles
such as sweetmeats and cigarettes. The newspapers may be hung on light
bars within the machine, these being supported at the end by a
carefully-adjusted cross piece, which, on the insertion of a penny in
the slot, moves just sufficiently to permit the end of one bar with
its newspaper to drop, and to precipitate the latter on to a table
forming the front of the machine. When the full complement of
newspapers has been exhausted the slot is automatically closed.

Some of the newspapers of the twentieth century will be given away
gratis, and will be, for the most part, owned by the principal
advertisers. This is the direction in which journalistic property is
now tending, and at any juncture steps might be taken, in one or other
of the great centres of newspaper enterprise, which would precipitate
the ultimate movement. Hardly any one who buys a half-penny paper
to-day imagines for a moment that there is any actual profit on the
article.

It is understood on all hands that the advertisers keep the newspapers
going and that the arrangement is mutually beneficial. Not that
either party can dictate to the other in matters outside of its own
province. The effect is simply to permit the great public to purchase
its news practically for the price of the paper and ink on which it is
conveyed; the condition being that the said public will permit its
eyes to be greeted with certain announcements placed in juxtaposition
to the news and comments.

Sooner or later, therefore, the idea will occur to some of the leading
advertisers to form a syndicate and give to the people a small
broadsheet containing briefly the daily narrative. The ponderous
newspapers of the latter end of the nineteenth century--filled full of
enough of linotype matter to occupy more than the whole day of the
subscriber in their perusal--will be to a large extent dispensed with;
and the new art of journalism will consist in saying things as
briefly--not as lengthily--as possible.




                             CHAPTER XIV.

                     INVENTION AND COLLECTIVISM.


The ownership of machinery and of all the varied appliances in the
evolution of which inventive genius is exercised is a matter which,
strictly speaking, does not belong to the domain of this work.
Nevertheless, in endeavouring to forecast the progress of invention
during the twentieth century, it is necessary to take count of the
risks involved in the inauguration of any public and social economical
systems which might tend to stifle freedom of thought and to
discourage the efforts of those who have suggestions of industrial
improvements to make.

It is plain that those economic forces which prevent the inventor from
having his ideas tested must to that extent retard the progress of
industrial improvement. Thousands of men, who imagine that they
possess the inventive talent in a highly developed degree, are either
crack-brained enthusiasts or else utterly unpractical men whose
services would never be worth anything at all in the work of
attacking difficult mechanical problems. It is in the task of
discriminating between this class and the true inventors that many
industrial organizers fail. Any economic system which offers
inducements to the directors of industrial enterprises to shirk the
onerous, and at times very irksome, duty of sifting out the good from
the bad must stand condemned not only on account of its wastefulness,
but by reason of its baneful effects in the discouragement of
inventive genius.

Considerations of this kind lead to the conclusion that during the
twentieth century the spread of collectivist or socialistic ideas, and
the adoption of methods of State and municipal control of production
and transport may have an important bearing upon the progress of
civilisation through the adoption of new inventions. Many thinking men
and women of the present generation are inclined to believe _the_
twentieth century invention _par excellence_ will be the bringing of
all the machinery of production, transport and exchange under the
official control of persons appointed by the State or by the
municipality, and therefore amenable to the vote of the people.
Projects of collectivism are in the air, and high hopes are
entertained that the twentieth century will be far more distinctively
marked by the revolution which it will witness in the social and
industrial organisation of the people than in the improvements
effected in the mechanical and other means for extending man's powers
over natural forces.

The average official naturally wishes to retain his billet. That is
the main motive which governs nearly all his official acts; and in the
treatment which he usually accords to the inventor he shows this
anxiety perhaps more clearly than in any other class of the actions of
his administration. He wants to make no mistakes, but whether he ever
scores a distinct and decided success is comparatively a matter of
indifference to him. So long as he does not give a handle to his
enemies to be used against him, he is fairly contented to go on from
year to year in a humdrum style.

Even a man of fine feeling and progressive ideas soon experiences the
numbing effects of the routine life after he has been a few years in
office. He knows that he will be judged rather on the negative than on
the positive principle, that is to say, for the things which it is
accounted he ought not to have done rather than for the more
enterprising good things which it is admitted he may have done.

Now any one who undertakes to encourage invention must necessarily
make mistakes. He may indeed know that one case of brilliant success
will make up for half a dozen comparative failures; but he reckons
that at any rate the blanks in the chances which he is taking will
numerically exceed the prizes. An official, however, will not dare to
draw blanks. Better for him to draw nothing at all. He must therefore
turn his back upon the inventor and approve of nothing which has not
been shown to be a great success elsewhere.

This means that the socialised and municipalised enterprises must
always lag behind those depending upon private effort; and the country
which imposes disabilities on the latter must, for a time at least,
lose its lead in the industrial race. This is what happened to
England, as contrasted with the United States, when, under the
influence of enthusiasm for future municipalisation, the British
Legislature laid heavy penalties upon those who should venture to
instal electric trams in the United Kingdom.

The American manufacturers and tramway companies, in their keen
competition with one another and perfect freedom to compete on even
terms with horse traction, soon took the lead in all matters
pertaining to electric traction, and the British public, at the close
of the nineteenth century, have had to witness the humiliating
spectacle of their own public authorities being forced to import
electrical apparatus, and even steam-engines applicable to dynamos
used for tramway purposes, from the other side of the Atlantic!

The lesson thus enforced will not in the end be missed, although it
may require a considerable time to be fully understood. Officialism is
a foe to inventive progress; and whether it exists under a regime of
collectivism or under one of autocracy, it must paralyse industrial
enterprise to that extent, thus rendering the country which has
adopted it liable to be outstripped by its competitors.

The true friend of inventive progress is generally the rising
competitor in a busy hive of industry where the difficulties of
securing a profitable footing are very considerable. Such a man is
ever on the watch for an opportunity to gain some leverage by which he
may raise himself to a level with older-established or richer
competitors. If he be a good employer his workmen enter into the
spirit of the competition, feeling that promotion will follow on any
services they may render. They may perhaps possess the inventive
talent themselves, or they may do even greater services by recognising
it in others and co-operating in their work. It is thus that
successful inventions are usually started on their useful careers.

It is therefore upon private enterprise that the principal onus of
advancing the inventions which will contribute to the progress of the
human race in the twentieth century must necessarily fall. The type of
man who will cheerfully work _pro bono publico_, with just as much
ardour as he would exhibit when labouring to advance his own
interests, may already be found here and there in civilised
communities at existing stages of development; but it is not
sufficiently numerous to enable the world to dispense with the
powerful stimulus of competition.

Just as a superior type of machinery can be elaborated during the
course of a single century, there is no doubt that--mainly through the
use of improved appliances for lessening the amount of brute force
which man needs to exert in his daily avocations--the nervous
organisations of the men and women constituting the rank and file
during the latter part of the twentieth century will be immensely
improved in sensitiveness. A corresponding advance will then take
place in the capacity for collectivism. But a human being of the high
class demanded for the carrying out of any scheme of State socialism
must be bred by a slow improvement during successive generations. A
hundred years do not constitute a long period of time in the process
of the organic evolution of the human race, and, as Tennyson declared,

  We are far from the noon of man--
  There is time for the race to grow.

Yet the public advantages of collectivist activities in certain
particular directions cannot for a moment be denied. Much waste and
heavy loss are entailed by the duplication of works of general utility
by rival owners, each of them, perhaps, only half utilising the full
capacities of his machinery or of the other plant upon which capital
has been expended.

Moreover, as soon as companies have become so large that their
managers and other officials are brought into no closer personal
relations with the shareholders than the town clerks, engineers, and
surveyors of cities, and the departmental heads of State bureaus are
associated with the voters and ratepayers, the systems of private and
of collective ownership begin to stand much more nearly on a par as
regards the non-encouragement which they offer to inventiveness.

One of the greatest discoveries of the twentieth century, therefore,
will be the adoption of a _via media_ which will admit of the
progressiveness of private ownership in promoting industrial
inventions, combined with the political progressiveness of
collectivism. One direction in which an important factor assisting in
the solution of this problem is to be expected is in the removal of
the causes which tend to make public officials so timid and
unprogressive.

So long as a mere temporary outcry about the apparent non-success of
some adopted improvement--whose real value perhaps cannot be proved
unless by the exercise of patience--may result in the dismissal or in
the disrating of the official who has recommended it, just so long
will all those who are called upon to act as guides to public
enterprises be compelled to stick to the most conservative lines in
the exercise of their duties. More assurance of permanence in
positions of public administration is needed.

The man upon whose shoulders rests the responsibility of adopting, or
of condemning, new proposals brought before him, ostensibly in the
interests of the public welfare, ought to be regarded as being called
upon to carry out _quasi_-judicial functions; and his tenure of
office, and his claim to a pension after a busy career, ought not to
depend upon the chances of the evanescent politics of the day. If a
man has proved, by his close and successful application to the study
of his profession--as evinced in the tests which he has passed as a
youth and during his subsequent career in subordinate positions--that
he is really a lover of hard work, and imbued with conscientious
devotion to duty, he may generally be trusted, when he has attained to
a position of superintendence, to do his utmost in the interests of
the public whom he serves. This is the theory upon which the
appointment of a judge in almost any English-speaking community is
understood to be made; and, although failures in its application may
occur now and then, there is no doubt whatever that on the average of
cases it works out well in practice.

If private manufacturers, whose success in life depends upon their
appreciation of talent and inventiveness, could be assured that in
dealing with public officials they would be brought into contact with
men of the standing indicated, instead of being confronted so
frequently with the demand for commissions and other kinds of solatium
on account of the risks undertaken in recommending anything new, they
would soon largely modify their distrust of what is known as
collectivism. It is the duty of the public whose servant an official
is, rather than of the private manufacturer, to insure him against
the danger of losing his position on account of any possible mistake
in the exercise of his judgment.

In short, the day is not far distant when the men upon whom devolves
the responsibility of examining into, and reporting upon, the claims
of those who profess to have made important industrial improvements
will be looked upon as exercising judicial functions of the very
highest type. When the important reforms arising from this recognition
have been introduced, the forces of collectivism will cease to range
themselves on the side of stolid conservatism in industry, as they
undoubtedly have done in the nineteenth century even while they
inconsistently professed to advance the cause of progress politically.

The inventor, who in the early part of the nineteenth century was
generally denounced as a public enemy, will, in the latter part of the
twentieth century, be hailed as a benefactor to the community, because
he will be judged by the ultimate, rather than by the immediate,
effects of his work, and because it will be the duty of the public
authorities to see to it that the dislocation of one industry
incidental the promotion of another by any invention does not, on the
whole, operate to throw people out of employment, but, on the
contrary, gives more constant work and better wages to all. But the
slow progress of the fundamental traits of human nature will retard
the attainment of this goal. The world has a long distance to travel
in the uphill road of industrial and social improvement before it can
succeed in obtaining a really true view of the part fulfilled by
inventive genius in contributing to human happiness.


                THE ABERDEEN UNIVERSITY PRESS LIMITED.




                                   A
                         CLASSIFIED CATALOGUE
                                  OF
                           SCIENTIFIC WORKS

                             PUBLISHED BY
                    MESSRS. LONGMANS, GREEN, & CO.

                   LONDON: 39 PATERNOSTER ROW, E.C.
                   NEW YORK: 91 & 93 FIFTH AVENUE.
                       BOMBAY: 32 HORNBY ROAD.


                               CONTENTS.

                                                                PAGE
  _ADVANCED SCIENCE MANUALS_                                      30
  AGRICULTURE                                                     27
  ASTRONOMY                                                       14
  BACTERIOLOGY                                                    25
  BIOLOGY                                                         25
  BOTANY AND GARDENING                                            26
  BUILDING CONSTRUCTION                                           10
  CHEMISTRY                                                        2
  DYNAMICS                                                         6
  ELECTRICITY                                                     11
  _ELEMENTARY SCIENCE MANUALS_                                    30
  ENGINEERING                                                     12
  GEOLOGY                                                         16
  HEALTH AND HYGIENE                                              18
  HEAT                                                             8
  HYDROSTATICS                                                     6
  LIGHT                                                            8
  _LONDON SCIENCE CLASS-BOOKS_                                    32
  _LONGMANS' CIVIL ENGINEERING SERIES_                            13
  MACHINE DRAWING AND DESIGN                                      13
  MAGNETISM                                                       11
  MANUFACTURES                                                    18
  MECHANICS                                                        6
  MEDICINE AND SURGERY                                            19
  METALLURGY                                                      14
  MINERALOGY                                                      14
  NATURAL HISTORY AND GENERAL SCIENCE                             17
  NAVAL ARCHITECTURE                                              13
  NAVIGATION                                                      14
  OPTICS                                                           8
  PHOTOGRAPHY                                                      8
  PHYSICS                                                          5
  PHYSIOGRAPHY                                                    16
  PHYSIOLOGY                                                      25
  _PRACTICAL ELEMENTARY SCIENCE SERIES_                           32
  _PROCTOR'S (R. A.) WORKS_                                       15
  SOUND                                                            8
  STATICS                                                          6
  STEAM, OIL AND GAS ENGINES                                       9
  STRENGTH OF MATERIALS                                           12
  TECHNOLOGY                                                      18
  TELEGRAPHY                                                      12
  TELEPHONE                                                       12
  _TEXT-BOOKS OF SCIENCE_                                         29
  THERMODYNAMICS                                                   8
  _TYNDALL'S (JOHN) WORKS_                                        28
  VETERINARY MEDICINE, ETC.                                       24
  WORKSHOP APPLIANCES                                             14
  ZOOLOGY                                                         25




                              CHEMISTRY.


_CROOKES._--SELECT METHODS IN CHEMICAL ANALYSIS, chiefly Inorganic.
By Sir WILLIAM CROOKES, F.R.S., etc. Third Edition, Rewritten and
Enlarged. With 67 Woodcuts. 8vo., 21_s._ net.

_FURNEAUX._--ELEMENTARY CHEMISTRY, Inorganic and Organic. By W.
FURNEAUX, F.R.G.S., Lecturer on Chemistry, London School Board. With
65 Illustrations and 155 Experiments. Crown 8vo., 2_s._ 6_d._

_GARRETT AND HARDEN._--AN ELEMENTARY COURSE OF PRACTICAL ORGANIC
CHEMISTRY. By F. C. GARRETT, M.Sc. (Vict. et Dunelm.), Assistant
Lecturer and Demonstrator in Chemistry, the Durham College of Science,
Newcastle-on-Tyne; and ARTHUR HARDEN, M.Sc. (Vict.), Ph.D., Assistant
Lecturer and Demonstrator in Chemistry, the Owens College, Manchester.
With 14 Illustrations. Crown 8vo., 2_s._

_JAGO._--Works by W. JAGO, F.C.S., F.I.C.

    INORGANIC CHEMISTRY, THEORETICAL AND PRACTICAL. With an
    Introduction to the Principles of Chemical Analysis Inorganic
    and Organic. With 63 Woodcuts and numerous Questions and
    Exercises. Fcp. 8vo., 2_s._ 6_d._

    AN INTRODUCTION TO PRACTICAL INORGANIC CHEMISTRY. Crown 8vo.,
    1_s._ 6_d._

    INORGANIC CHEMISTRY, THEORETICAL AND PRACTICAL. A Manual for
    Students in Advanced Classes of the Science and Art
    Department. With Plate of Spectra and 78 Woodcuts. Crown
    8vo., 4_s._ 6_d._

_KOLBE._--A SHORT TEXT-BOOK OF INORGANIC CHEMISTRY. By Dr. HERMANN
KOLBE. Translated and Edited by T. S. HUMPIDGE, Ph.D. With 66
Illustrations. Crown 8vo., 8_s._ 6_d._

_MENDELÉEFF._--THE PRINCIPLES OF CHEMISTRY. By D. MENDELÉEFF.
Translated from the Russian (Sixth Edition) by GEORGE KAMENSKY,
A.R.S.M., of the Imperial Mint, St. Petersburg; and Edited by T. A.
LAWSON, B.Sc, Ph.D., Fellow of the Institute of Chemistry. With 96
Diagrams and Illustrations. 2 vols. 8vo., 36_s._

_MEYER._--OUTLINES OF THEORETICAL CHEMISTRY. By LOTHAR MEYER,
Professor of Chemistry in the University of Tübingen. Translated by
Professors P. PHILLIPS BEDSON, D.Sc., and W. CARLETON WILLIAMS, B.Sc.
8vo., 9_s._

_MILLER._--INTRODUCTION TO THE STUDY OF INORGANIC CHEMISTRY. By W.
ALLEN MILLER, M.D., LL.D. With 71 Woodcuts, Fcp. 8vo., 3_s._ 6_d._

_MUIR._--A COURSE OF PRACTICAL CHEMISTRY. By M. M. P. MUIR, M.A.,
Fellow and Prælector in Chemistry of Gonville and Caius College,
Cambridge. (3 Parts.)

    Part I. Elementary. Crown 8vo., 4_s._ 6_d._

    Part II. Intermediate. Crown 8vo., 4_s._ 6_d._

    Part III.                                   [_In preparation._

_NEWTH._--Works by G. S. NEWTH, F.I.C, F.C.S., Demonstrator in the
Royal College of Science, London.

    CHEMICAL LECTURE EXPERIMENTS. With 230 Illustrations. Crown
    8vo., 6_s._

    CHEMICAL ANALYSIS, QUANTITATIVE AND QUALITATIVE. With 100
    Illustrations. Crown 8vo., 6_s._ 6_d._

    A TEXT-BOOK OF INORGANIC CHEMISTRY. With 146 Illustrations.
    Crown 8vo., 6_s._ 6_d._

    ELEMENTARY PRACTICAL CHEMISTRY. With 108 Illustrations and
    254 Experiments. Crown 8vo., 2_s._ 6_d._

_OSTWALD._--SOLUTIONS. By W. OSTWALD, Professor of Chemistry in the
University of Leipzig. Being the Fourth Book, with some additions, of
the Second Edition of Oswald's 'Lehrbuch der allgemeinen Chemie'.
Translated by M. M. PATTISON MUIR, Fellow and Prælector in Chemistry
of Gonville and Caius College, Cambridge. 8vo., 10_s._ 6_d._

_PERKIN._--QUALITATIVE ANALYSIS (INORGANIC AND ORGANIC). By F. MOLLWO
PERKIN, Ph.D.

_REYNOLDS._--EXPERIMENTAL CHEMISTRY FOR JUNIOR STUDENTS. By J. EMERSON
REYNOLDS, M.D., F.R.S., Professor of Chemistry, University of Dublin.
Fcp. 8vo., with numerous Woodcuts.

    Part I. Introductory. Fcp. 8vo., 1_s._ 6_d._

    Part II. Non-Metals, with an Appendix on Systematic Testing
    for Acids. Fcp. 8vo., 2_s._ 6_d._

    Part III. Metals, and Allied Bodies. Fcp. 8vo., 3_s._ 6_d._

    Part IV. Carbon Compounds. Fcp. 8vo., 4_s._

_SHENSTONE._--Works by W. A. SHENSTONE, F.R.S., Lecturer on Chemistry
in Clifton College.

    THE METHODS OF GLASS-BLOWING. For the use of Physical and
    Chemical Students. With 42 Illustrations. Crown 8vo., 1_s._
    6_d._

    A PRACTICAL INTRODUCTION TO CHEMISTRY. Intended to give a
    Practical acquaintance with the Elementary Facts and
    Principles of Chemistry. With 25 Illustrations. Crown 8vo.,
    2_s._

_THORNTON AND PEARSON._--NOTES ON VOLUMETRIC ANALYSIS. By ARTHUR
THORNTON, M.A., and MARCHANT PEARSON, B.A., Assistant Science Master,
Bradford Grammar School. Medium 8vo., 2_s._

_THORPE._--Works by T. E. THORPE, C.B., B.Sc. (Vict.), Ph.D., F.R.S.,
Professor of Chemistry in the Royal College of Science, South
Kensington. Assisted by Eminent Contributors.

    A DICTIONARY OF APPLIED CHEMISTRY. 3 vols. 8vo. Vols. I. and
    II., 42_s._ each. Vol. III., 63_s._

    QUANTITATIVE CHEMICAL ANALYSIS. With 88 Woodcuts. Fcp. 8vo.,
    4_s._ 6_d._

_THORPE AND MUIR._--QUALITATIVE CHEMICAL ANALYSIS AND LABORATORY
PRACTICE. By T. E. THORPE, C.B., Ph.D., D.Sc., F.R.S., and M. M.
PATTISON MUIR, M.A. With Plate of Spectra and 57 Woodcuts. Fcp. 8vo.,
3_s._ 6_d._

_TILDEN._--Works by WILLIAM A. TILDEN, D.Sc. London, F.R.S., Professor
of Chemistry in the Royal College of Science, South Kensington.

    A SHORT HISTORY OF THE PROGRESS OF SCIENTIFIC CHEMISTRY IN
    OUR OWN TIMES. Crown 8vo., 5_s._ net.

    INTRODUCTION TO THE STUDY OF CHEMICAL PHILOSOPHY. The
    Principles of Theoretical and Systematic Chemistry. With 5
    Woodcuts. With or without the ANSWERS of Problems. Fcp. 8vo.,
    4_s._ 6_d._

    PRACTICAL CHEMISTRY. The principles of Qualitative Analysis.
    Fcp. 8vo., 1_s._ 6_d._

    HINTS ON THE TEACHING OF ELEMENTARY CHEMISTRY IN SCHOOLS AND
    SCIENCE CLASSES. With 7 Illustrations. Crown 8vo., 2_s._

_WATTS'_ DICTIONARY OF CHEMISTRY. Revised and entirely Rewritten by H.
FORSTER MORLEY, M.A., D.Sc., Fellow of, and lately Assistant Professor
of Chemistry in, University College, London; and M. M. PATTISON MUIR,
M.A., F.R.S.E., Fellow, and Prælector in Chemistry, of Gonville and
Caius College, Cambridge. Assisted by Eminent Contributors. 4 vols.
8vo. Vols. I. and II., 42_s._ each. Vol. III., 50_s._ Vol. IV., 63_s._

_WHITELEY._--Works by R. LLOYD WHITELEY, F.I.C., Principal of the
Municipal Science School, West Bromwich.

    CHEMICAL CALCULATIONS. With Explanatory Notes, Problems and
    Answers, specially adapted for use in Colleges and Science
    Schools. With a Preface by Professor F. CLOWES, D.Sc. (Lond.),
    F.I.C. Crown 8vo., 2_s._

    ORGANIC CHEMISTRY: the Fatty Compounds. With 45 Illustrations.
    Crown 8vo., 3_s._ 6_d._




                            PHYSICS, ETC.


_GANOT._--Works by PROFESSOR GANOT. Translated and Edited by E.
ATKINSON, Ph.D., F.C.S.

    ELEMENTARY TREATISE ON PHYSICS, Experimental and Applied.
    With 9 Coloured Plates and Maps, and 1057 Woodcuts, and
    Appendix of Problems and Examples with Answers. Crown 8vo.,
    15_s._

    NATURAL PHILOSOPHY FOR GENERAL READERS AND YOUNG PERSONS.
    With 7 Plates, 624 Woodcuts, and an Appendix of Questions.
    Crown 8vo., 7_s._ 6_d._

_GLAZEBROOK AND SHAW._--PRACTICAL PHYSICS. By R. T. GLAZEBROOK, M.A.,
F.R.S., and W. N. SHAW, M.A. With 134 Woodcuts. Fcp. 8vo., 7_s._ 6_d._

_GUTHRIE._--MOLECULAR PHYSICS AND SOUND. By F. GUTHRIE, Ph.D. With 91
Diagrams. Fcp. 8vo., 1_s._ 6_d._

_HELMHOLTZ._--POPULAR LECTURES ON SCIENTIFIC SUBJECTS. By HERMANN VON
HELMHOLTZ. Translated by E. ATKINSON, Ph.D., F.C.S., formerly
Professor of Experimental Science, Staff College. With 68
Illustrations. 2 vols., crown 8vo., 3_s._ 6_d._ each.

    CONTENTS.--Vol. I.--The Relation of Natural Science to
    Science in General--Goethe's Scientific Researches--The
    Physiological Causes of Harmony in Music--Ice and
    Glaciers--The Interaction of the Natural Forces--The Recent
    Progress of the Theory of Vision--The Conservation of
    Force--The Aim and Progress of Physical Science.

    CONTENTS.--Vol. II.--Gustav Magnus. In Memoriam--The Origin
    and Significance of Geometrical Axioms--The Relation of
    Optics to Painting--The Origin of the Planetary
    System--Thought in Medicine--Academic Freedom in German
    Universities--Hermann Von Helmholtz--An Autobiographical
    Sketch.

_HENDERSON._--ELEMENTARY PHYSICS. By JOHN HENDERSON, D.Sc. (Edin.),
A.I.E.E., Physics Department, Borough Road Polytechnic. Crown 8vo.,
2_s._ 6_d._

_MACLEAN._--EXERCISES IN NATURAL PHILOSOPHY. By MAGNUS MACLEAN, D.Sc.,
Professor of Electrical Engineering at the Glasgow and West of
Scotland Technical College. Crown 8vo., 4_s._ 6_d._

_MEYER._--THE KINETIC THEORY OF GASES. Elementary Treatise, with
Mathematical Appendices. By Dr. OSKAR EMIL MEYER, Professor of Physics
at the University of Breslau. Second Revised Edition. Translated by
ROBERT E. BAYNES, M.A., Student of Christ Church, Oxford, and Dr.
Lee's Reader in Physics. 8vo., 15_s._ net.

_VAN 'THOFF._--THE ARRANGEMENT OF ATOMS IN SPACE. By J. H. VAN T'HOFF.
Second, Revised, and Enlarged Edition. With a Preface by JOHANNES
WISLICENUS, Professor of Chemistry at the University of Leipzig; and
an Appendix 'Stereo-chemistry among Inorganic Substances,' by ALFRED
WERNER, Professor of Chemistry at the University of Zürich. Translated
and Edited by ARNOLD EILOART. Crown 8vo., 6_s._ 6_d._

_WATSON._--Works by W. WATSON, B.Sc., Assistant Professor of Physics
in the Royal College of Science, London; Assistant Examiner in
Physics, Science and Art Department.

    ELEMENTARY PRACTICAL PHYSICS: a Laboratory Manual for Use in
    Organised Science Schools. With 120 Illustrations and 193
    Exercises. Crown 8vo., 2_s._ 6_d._

    A TEXT-BOOK OF PHYSICS. With 564 Diagrams and Illustrations.
    Large crown 8vo., 10_s._ 6_d._

_WORTHINGTON._--A FIRST COURSE OF PHYSICAL LABORATORY PRACTICE.
Containing 264 Experiments. By A. M. WORTHINGTON, M.A., F.R.S. With
Illustrations. Crown 8vo., 4_s._ 6_d._

_WRIGHT._--ELEMENTARY PHYSICS. By MARK R. WRIGHT, M.A., Professor of
Normal Education, Durham College of Science. With 242 Illustrations.
Crown 8vo., 2_s._ 6_d._




           MECHANICS, DYNAMICS, STATICS, HYDROSTATICS, ETC.


_BALL._--A CLASS-BOOK OF MECHANICS. By Sir R. S. BALL, LL.D. 89
Diagrams. Fcp. 8vo., 1_s._ 6_d._

_GELDARD._--STATICS AND DYNAMICS. By C. GELDARD, M.A., formerly
Scholar of Trinity College, Cambridge. Crown 8vo., 5_s._

_GOODEVE._--Works by T. M. GOODEVE, M.A., formerly Professor of
Mechanics at the Normal School of Science, and the Royal School of
Mines.

    THE ELEMENTS OF MECHANISM. With 357 Woodcuts. Crown 8vo.,
    6_s._

    PRINCIPLES OF MECHANICS. With 253 Woodcuts and numerous
    Examples. Crown 8vo., 6_s._

    A MANUAL OF MECHANICS: an Elementary Text-Book for Students
    of Applied Mechanics. With 138 Illustrations and Diagrams and
    188 Examples taken from the Science Department Examination
    Papers, with Answers. Fcp. 8vo., 2_s._ 6_d._

_GOODMAN._--MECHANICS APPLIED TO ENGINEERING. By JOHN GOODMAN,
Wh. Sch., A.M.I.C.E., M.I.M.E., Professor of Engineering in the
Yorkshire College, Leeds (Victoria University). With 620 Illustrations
and numerous examples. Crown 8vo., 7_s._ 6_d._ net.

_GRIEVE._--LESSONS IN ELEMENTARY MECHANICS. By W. H. GRIEVE, late
Engineer, R.N., Science Demonstrator for the London School Board, etc.

    Stage 1. With 165 Illustrations and a large number of
    Examples. Fcp. 8vo., 1_s._ 6_d._

    Stage 2. With 122 Illustrations. Fcp. 8vo., 1_s._ 6_d._

    Stage 3. With 103 Illustrations. Fcp. 8vo., 1_s._

_MAGNUS._--Works by SIR PHILIP MAGNUS, B.Sc., B.A.

    LESSONS IN ELEMENTARY MECHANICS. Introductory to the study of
    Physical Science. Designed for the Use of Schools, and of
    Candidates for the London Matriculation and other
    Examinations. With numerous Exercises, Examples, Examination
    Questions, and Solutions, etc., from 1870-1895. With Answers,
    and 131 Woodcuts. Fcp. 8vo., 3_s._ 6_d._
        Key for the use of Teachers only, price 5_s._ 3-1/2_d._

    HYDROSTATICS AND PNEUMATICS. Fcp. 8vo., 1_s._ 6_d._; or, with
    Answers, 2_s._ The Worked Solutions of the Problems, 2_s._

_ROBINSON._--Works by the Rev. J. L. ROBINSON, M.A.

    ELEMENTS OF DYNAMICS (Kinetics and Statics). With numerous
    Exercises. A Text-book for Junior Students. Crown 8vo., 6_s._

    A FIRST BOOK IN STATICS AND DYNAMICS. With numerous Examples
    and Answers. Crown 8vo, 3_s._ 6_d._
        Sold separately: Statics, 2_s._; Dynamics, 2_s._

_SMITH._--Works by J. HAMBLIN SMITH, M.A.

    ELEMENTARY STATICS. Crown 8vo., 3_s._

    ELEMENTARY HYDROSTATICS. Crown 8vo., 3_s._

    KEY TO STATICS AND HYDROSTATICS. Crown 8vo., 6_s._

_TARLETON._--AN INTRODUCTION TO THE MATHEMATICAL THEORY OF ATTRACTION.
By FRANCIS A. TARLETON, LL.D., Sc.D., Fellow of Trinity College, and
Professor of Natural Philosophy in the University of Dublin. Crown
8vo., 10_s._ 6_d._

_TAYLOR._--Works by J. E. TAYLOR, M.A., B.Sc. (Lond.).

    THEORETICAL MECHANICS, including Hydrostatics and Pneumatics.
    With 175 Diagrams and Illustrations, and 522 Examination
    Questions and Answers. Crown 8vo., 2_s._ 6_d._

    THEORETICAL MECHANICS--SOLIDS. With 163 Illustrations, 120
    Worked Examples and over 500 Examples from Examination
    Papers, etc. Crown 8vo., 2_s._ 6_d._

    THEORETICAL MECHANICS.--FLUIDS. With 122 Illustrations,
    numerous Worked Examples, and about 500 Examples from
    Examination Papers, etc. Crown 8vo., 2_s._ 6_d._

_THORNTON._--THEORETICAL MECHANICS--SOLIDS. Including Kinematics,
Statics and Kinetics. By ARTHUR THORNTON, M.A., F.R.A.S. With 200
Illustrations, 130 Worked Examples, and over 900 Examples from
Examination Papers, etc. Crown 8vo., 4_s._ 6_d._

_TWISDEN._--Works by the Rev. JOHN F. TWISDEN, M.A.

    PRACTICAL MECHANICS; an Elementary Introduction to their
    Study. With 855 Exercises, and 184 Figures and Diagrams.
    Crown 8vo., 10_s._ 6_d._

    THEORETICAL MECHANICS. With 172 Examples, numerous Exercises,
    and 154 Diagrams. Crown 8vo., 8_s._ 6_d._

_WILLIAMSON._--INTRODUCTION TO THE MATHEMATICAL
THEORY OF THE STRESS AND STRAIN OF ELASTIC
SOLIDS. By BENJAMIN WILLIAMSON, D.Sc., F.R.S. Crown 8vo., 5_s._

_WILLIAMSON AND TARLETON._--AN ELEMENTARY TREATISE ON DYNAMICS.
Containing Applications to Thermodynamics, with numerous Examples. By
BENJAMIN WILLIAMSON, D.Sc., F.R.S., and FRANCIS A. TARLETON, LL.D.
Crown 8vo., 10_s._ 6_d._

_WORTHINGTON._--DYNAMICS OF ROTATION: an Elementary Introduction to
Rigid Dynamics. By A. M. WORTHINGTON, M.A., F.R.S. Crown 8vo., 4_s._
6_d._




                        OPTICS AND PHOTOGRAPHY.


_ABNEY._--A TREATISE ON PHOTOGRAPHY. By Sir WILLIAM DE WIVELESLIE
ABNEY, K.C.B., F.R.S., Principal Assistant Secretary of the Secondary
Department of the Board of Education. With 115 Woodcuts. Fcp. 8vo.,
3_s._ 6_d._

_GLAZEBROOK._--PHYSICAL OPTICS. By R. T. GLAZEBROOK, M.A., F.R.S.,
Principal of University College, Liverpool. With 183 Woodcuts of
Apparatus, etc. Fcp. 8vo., 6_s._

_WRIGHT._--OPTICAL PROJECTION: a Treatise on the Use of the Lantern in
Exhibition and Scientific Demonstration. By LEWIS WRIGHT, Author of
'Light: a Course of Experimental Optics'. With 232 Illustrations.
Crown 8vo., 6_s._




                SOUND, LIGHT, HEAT, AND THERMODYNAMICS.


_CUMMING._--HEAT TREATED EXPERIMENTALLY. By LINNÆUS CUMMING, M.A. With
192 Illustrations. Crown 8vo., 4_s._ 6_d._

_DAY._--NUMERICAL EXAMPLES IN HEAT. By R. E. DAY, M.A. Fcp. 8vo.,
3_s._ 6_d._

_EMTAGE._--LIGHT. By W. T. A. EMTAGE, M.A. With 232 Illustrations.
Crown 8vo., 6_s._

_HELMHOLTZ._--ON THE SENSATIONS OF TONE AS A PHYSIOLOGICAL BASIS FOR
THE THEORY OF MUSIC. By HERMANN VON HELMHOLTZ. Royal 8vo., 28_s._

_MADAN._--AN ELEMENTARY TEXT-BOOK ON HEAT For the Use of Schools. By
H. G. MADAN, M.A., F.C.S., Fellow of Queen's College, Oxford; late
Assistant Master at Eton College. Crown 8vo., 9_s._

_MAXWELL._--THEORY OF HEAT. By J. CLERK MAXWELL, M.A., F.R.SS., L.
and E. With Corrections and Additions by Lord RAYLEIGH. With 38
Illustrations. Fcp. 8vo., 4_s._ 6_d._

_SMITH._--THE STUDY OF HEAT. By J. HAMBLIN SMITH M.A., of Gonville and
Caius College, Cambridge. Crown 8vo., 3_s._

_TYNDALL._--Works by JOHN TYNDALL, D.C.L., F.R.S See p. 28.

_WORMELL._--A CLASS-BOOK OF THERMODYNAMICS By RICHARD WORMELL, B.Sc.,
M.A. Fcp. 8vo., 1_s._ 6_d._

_WRIGHT._--Works by MARK R. WRIGHT, M.A.

    SOUND, LIGHT, AND HEAT. With 160 Diagrams and Illustrations.
    Crown 8vo., 2_s._ 6_d._

    ADVANCED HEAT. With 136 Diagrams and numerous Examples and
    Examination Papers. Crown 8vo., 4_s._ 6_d._




                     STEAM, OIL, AND GAS ENGINES.

_BALE._--A HAND-BOOK FOR STEAM USERS; being Rules for Engine Drivers
and Boiler Attendants, with Notes on Steam Engine and Boiler
Management and Steam Boiler Explosions. By M. POWIS BALE, M.I.M.E.,
A.M.I.C.E. Fcp. 8vo., 2_s._ 6_d._

_CLERK._--THE GAS AND OIL ENGINE. By DUGALD CLERK, Associate Member of
the Institution of Civil Engineers, Fellow of the Chemical Society,
Member of the Royal Institution, Fellow of the Institute of Patent
Agents. With 228 Illustrations. 8vo., 15_s._

_HOLMES._--THE STEAM ENGINE. By George C. V. Holmes, Whitworth
Scholar, Secretary of the Institution of Naval Architects. With 212
Woodcuts. Fcp. 8vo., 6_s._

_NORRIS._--A PRACTICAL TREATISE ON THE 'OTTO' CYCLE GAS ENGINE. By
WILLIAM NORRIS, M.I.Mech.E. With 207 Illustrations. 8vo., 10_s._ 6_d._

_RIPPER._--Works by WILLIAM RIPPER, Professor of Mechanical
Engineering in the Sheffield Technical School.

     STEAM. With 142 Illustrations. Crown 8vo., 2_s._ 6_d._

     STEAM ENGINE THEORY AND PRACTICE. With 438 Illustrations.
     8vo., 9_s._

_SENNETT AND ORAM._--THE MARINE STEAM ENGINE: A Treatise for
Engineering Students, Young Engineers and Officers of the Royal Navy
and Mercantile Marine. By the late RICHARD SENNETT, Engineer-in-Chief
of the Navy, etc.; and HENRY J. ORAM, Senior Engineer Inspector at the
Admiralty, Inspector of Machinery in H.M. Fleet, etc. With 414
Diagrams. 8vo., 21_s._

_STROMEYER._--MARINE BOILER MANAGEMENT AND CONSTRUCTION. Being a
Treatise on Boiler Troubles and Repairs, Corrosion, Fuels, and Heat,
on the properties of Iron and Steel, on Boiler Mechanics, Workshop
Practices, and Boiler Design. By C. E. STROMEYER, Member of the
Institute of Naval Architects, etc. 8vo., 18_s._ net.




                        BUILDING CONSTRUCTION.


ADVANCED BUILDING CONSTRUCTION. By the Author of 'Rivingtons' Notes on
Building Construction'. With 385 Illustrations. Crown 8vo., 4_s._
6_d._

_BURRELL._--BUILDING CONSTRUCTION. By EDWARD J. BURRELL, Second Master
of the People's Palace Technical School, London. With 303 Working
Drawings. Crown 8vo., 2_s._ 6_d._

_SEDDON._--BUILDER'S WORK AND THE BUILDING TRADES. By Col. H. C.
SEDDON, R.E., late Superintending Engineer, H.M.'s Dockyard,
Portsmouth; Examiner in Building Construction, Science and Art
Department, South Kensington. With numerous Illustrations. Medium
8vo., 16_s._


            RIVINGTONS' COURSE OF BUILDING CONSTRUCTION.

NOTES ON BUILDING CONSTRUCTION. Arranged to meet the requirements of
the syllabus of the Science and Art Department of the Committee of
Council on Education, South Kensington. Medium 8vo.

    Part I. Elementary Stage. With 552 Woodcuts, 10_s._ 6_d._

    Part II. Advanced Stage. With 479 Woodcuts, 10_s._ 6_d._

    Part III. Materials. Course for Honours. With 188 Woodcuts,
    21_s._

    Part IV. Calculations for Building Structures. Course for
    Honours. With 597 Woodcuts, 15_s._




                      ELECTRICITY AND MAGNETISM.


_CARUS-WILSON._--ELECTRO-DYNAMICS: the Direct-Current Motor. By
CHARLES ASHLEY CARUS-WILSON, M.A. Cantab. With 71 Diagrams, and a
Series of Problems, with Answers. Crown 8vo., 7_s._ 6_d._

_CUMMING._--ELECTRICITY TREATED EXPERIMENTALLY. By LINNÆUS CUMMING,
M.A. With 242 Illustrations. Cr. 8vo., 4_s._ 6_d._

_DAY._--EXERCISES IN ELECTRICAL AND MAGNETIC MEASUREMENTS, with
Answers. By R. E. DAY. 12mo., 3_s._ 6_d._

_GORE._--THE ART OF ELECTRO-METALLURGY, including all known Processes
of Electro-Deposition. By G. GORE, LL.D., F.R.S. With 56 Woodcuts.
Fcp. 8vo., 6_s._

_HENDERSON._--Works by JOHN HENDERSON, D.Sc., F.R.S.E.

    PRACTICAL ELECTRICITY AND MAGNETISM. With 159 Illustrations
    and Diagrams. Crown 8vo., 6_s._ 6_d._

    PRELIMINARY PRACTICAL MAGNETISM AND ELECTRICITY: A Text-book
    for Organised Science Schools and Elementary Evening Science
    Schools. Crown 8vo., 1_s._

_JENKIN._--ELECTRICITY AND MAGNETISM. By FLEEMING JENKIN, F.R.S.S., L.
and E., M.I.C.E. With 177 Illustrations. Fcp. 8vo., 3_s._ 6_d._

_JOUBERT._--ELEMENTARY TREATISE ON ELECTRICITY AND MAGNETISM. By G. C.
FOSTER, F.R.S., and E. ATKINSON, Ph.D. With 381 Illustrations. Crown
8vo., 7_s._ 6_d._

_JOYCE._--EXAMPLES IN ELECTRICAL ENGINEERING. By SAMUEL JOYCE,
A.I.E.E. Crown 8vo., 5_s._

_LARDEN._--ELECTRICITY FOR PUBLIC SCHOOLS AND COLLEGES. By W. LARDEN,
M.A. With 215 Illustrations. Cr. 8vo., 6_s._

_MACLEAN AND MARCHANT._--ELEMENTARY QUESTIONS IN ELECTRICITY AND
MAGNETISM. With Answers. Compiled by MAGNUS MACLEAN, D.Sc., M.I.E.E.,
and E. W. MARCHANT, D.Sc., A.I.E.E. Crown 8vo., 1_s._

_MERRIFIELD._--MAGNETISM AND DEVIATION OF THE COMPASS. By JOHN
MERRIFIELD, LL.D., F.R.A.S., 18mo., 2_s._ 6_d._

_PARR._--PRACTICAL ELECTRICAL TESTING IN PHYSICS AND ELECTRICAL
ENGINEERING: being a Course suitable for First and Second Year
Students and others. By G. D. ASPINALL PARR, Assoc. M.I.E.E., Head of
the Electrical Engineering Department, Yorkshire College, Victoria
University. With Illustrations. Crown 8vo.

_POYSER._--Works by A. W. POYSER, M.A.

     MAGNETISM AND ELECTRICITY. With 235 Illustrations. Crown
     8vo., 2_s._ 6_d._

     ADVANCED ELECTRICITY AND MAGNETISM. With 317 Illustrations.
     Crown 8vo., 4_s._ 6_d._

_SLINGO AND BROOKER._--Works by W. SLINGO and A. BROOKER.

     ELECTRICAL ENGINEERING FOR ELECTRIC LIGHT ARTISANS AND
     STUDENTS. With 359 Illustrations. Crown 8vo., 12_s._

     PROBLEMS AND SOLUTIONS IN ELEMENTARY ELECTRICITY AND
     MAGNETISM. With 67 Illustrations. Cr. 8vo., 2_s._

_TYNDALL._--Works by JOHN TYNDALL, D.C.L., F.R.S. See p. 28.




                TELEGRAPHY AND THE TELEPHONE.


_HOPKINS._--THE TELEPHONE: Outlines of the Development of Transmitters
and Receivers. By WILLIAM J. HOPKINS, Professor of Physics in the
Drexel Institute, Philadelphia; Author of 'Telephone Lines and their
Properties,' etc. With 7 Full-page Illustrations and 39 Diagrams.
Crown 8vo., 3_s._ 6_d._

_PREECE AND SIVEWRIGHT._--TELEGRAPHY. By Sir W. H. PREECE, K.C.B.,
F.R.S., V.P.Inst., C.E., etc., Engineer-in-Chief and Electrician, Post
Office Telegraphs; and Sir J. SIVEWRIGHT, K.C.M.G., General Manager,
South African Telegraphs. With 267 Illustrations. Fcp. 8vo., 6_s._




               ENGINEERING, STRENGTH OF MATERIALS, ETC.


_ANDERSON._--THE STRENGTH OF MATERIALS AND STRUCTURES: the Strength of
Materials as depending on their Quality and as ascertained by Testing
Apparatus. By Sir J. ANDERSON, C.E., LL.D., F.R.S.E. With 66 Woodcuts.
Fcp. 8vo., 3_s._ 6_d._

_BARRY._--RAILWAY APPLIANCES: a Description of Details of Railway
Construction subsequent to the completion of the Earthworks and
Structures. By Sir JOHN WOLFE BARRY, K.C.B., F.R.S., M.I.C.E. With 218
Woodcuts. Fcp. 8vo., 4_s._ 6_d._

_GOODMAN._--MECHANICS APPLIED TO ENGINEERING. By JOHN GOODMAN,
Wh.Sch., A.M.I.C.E., M.I.M.E., Professor of Engineering in the
Yorkshire College, Leeds (Victoria University). With 620 Illustrations
and numerous Examples. Crown 8vo., 7_s._ 6_d._ net.

_LOW._--A POCKET-BOOK FOR MECHANICAL ENGINEERS. By DAVID ALLAN LOW
(Whitworth Scholar), M.I.Mech.E., Professor of Engineering, East
London Technical College (People's Palace), London. With over 1000
specially prepared Illustrations. Fcp. 8vo., gilt edges, rounded
corners, 7_s._ 6_d._

_SMITH._--GRAPHICS, or the Art of Calculation by Drawing Lines,
applied especially to Mechanical Engineering. By ROBERT H. SMITH,
Professor of Engineering, Mason College, Birmingham. Part I. With
separate Atlas of 29 Plates containing 97 Diagrams. 8vo., 15_s._

_STONEY._--THE THEORY OF STRESSES IN GIRDERS AND SIMILAR STRUCTURES;
with Practical Observations on the Strength and other Properties of
Materials. By BINDON B. STONEY, LL.D., F.R.S., M.I.C.E. With 5 Plates
and 143 Illust. in the Text. Royal 8vo., 36_s._

_UNWIN._--Works by W. CAWTHORNE UNWIN, F.R.S., B.S.C.

     THE TESTING OF MATERIALS OF CONSTRUCTION. A Text-book for
     the Engineering Laboratory and a Collection of the Results
     of Experiment. With 5 Plates and 188 Illustrations and
     Diagrams in the Text. 8vo., 16_s._ net.

     ON THE DEVELOPMENT AND TRANSMISSION OF POWER FROM CENTRAL
     STATIONS: being the Howard Lectures delivered at the Society
     of Arts in 1893. With 81 Diagrams. 8vo., 10_s._ net.

_WARREN._--ENGINEERING CONSTRUCTION IN IRON, STEEL, AND TIMBER. By
WILLIAM HENRY WARREN, Challis Professor of Civil and Mechanical
Engineering, University of Sydney. With 13 Folding Plates and 375
Diagrams. Royal 8vo., 16_s._ net.




                  LONGMANS' CIVIL ENGINEERING SERIES.
       Edited by the Author of 'Notes on Building Construction'.

TIDAL RIVERS: their (1) Hydraulics, (2) Improvement, (3) Navigation.
By W. H. WHEELER, M.Inst.C.E. With 75 Illustrations. Medium 8vo.,
16_s._ net.

NOTES ON DOCKS AND DOCK CONSTRUCTION. By C. COLSON, M.Inst.C.E.,
Deputy Civil Engineer-in-Chief, Admiralty. With 365 Illustrations.
Medium 8vo., 21_s._ net.

PRINCIPLES AND PRACTICE OF HARBOUR CONSTRUCTION. By WILLIAM SHIELD,
F.R.S.E., M.Inst.C.E., and Executive Engineer, National Harbour of
Refuge, Peterhead, N.B. With 97 Illustrations. Medium 8vo., 15_s._
net.

CALCULATIONS IN HYDRAULIC ENGINEERING: a Practical Text-Book for the
use of Students, Draughtsmen and Engineers. By T. CLAXTON FIDLER,
M.Inst.C.E., Professor of Engineering, University College, Dundee.

    Part I. Fluid Pressure and the Calculation of its Effects in
    Engineering Structures. With numerous Illustrations and
    Examples. 8vo., 6_s._ 6_d._ net.

RAILWAY CONSTRUCTION. By W. H. MILLS, M.I.C.E., Engineer-in-Chief of
the Great Northern Railway of Ireland. With 516 Illustrations and
Diagrams. 8vo., 18_s._ net.




                         NAVAL ARCHITECTURE.


_ATTWOOD._--TEXT-BOOK OF THEORETICAL NAVAL ARCHITECTURE: a Manual for
Students of Science Classes and Draughtsmen Engaged in Shipbuilders'
and Naval Architects' Drawing Offices. By EDWARD LEWIS ATTWOOD,
Assistant Constructor, Royal Navy; Member of the Institution of Naval
Architects. With 114 Diagrams. Crown 8vo., 7_s._ 6_d._

_WATSON._--NAVAL ARCHITECTURE: A Manual of Laying-off Iron, Steel and
Composite Vessels. By THOMAS H. WATSON, Lecturer on Naval Architecture
at the Durham College of Science, Newcastle-upon-Tyne. With numerous
Illustrations. Royal 8vo., 15_s._ net.




                      MACHINE DRAWING AND DESIGN.


_LOW._--Works by DAVID ALLAN LOW, Professor of Engineering, East
London Technical College (People's Palace).

     IMPROVED DRAWING SCALES. 6_d._ in case.

     AN INTRODUCTION TO MACHINE DRAWING AND DESIGN. With 153
     Illustrations and Diagrams. Crown 8vo, 2_s._ 6_d._

_LOW AND BEVIS._--A MANUAL OF MACHINE DRAWING AND DESIGN. By DAVID
ALLAN LOW and ALFRED WILLIAM BEVIS, M.I.Mech.E. With 700
Illustrations. 8vo., 7_s._ 6_d._

_UNWIN._--THE ELEMENTS OF MACHINE DESIGN. By W. CAWTHORNE UNWIN,
F.R.S.

     Part I. General Principles, Fastenings, and Transmissive
     Machinery. With 304 Diagrams, etc. Fcp. 8vo., 6_s._

     Part II. Chiefly on Engine Details. With 174 Woodcuts. Fcp.
     8vo., 4_s._ 6_d._




                       WORKSHOP APPLIANCES, ETC.


_NORTHCOTT._--LATHES AND TURNING, Simple, Mechanical and Ornamental.
By W. H. NORTHCOTT. With 338 Illustrations. 8vo., 18_s._

_SHELLEY._--WORKSHOP APPLIANCES, including Descriptions of some of the
Gauging and Measuring Instruments, Hand-cutting Tools, Lathes,
Drilling, Planeing, and other Machine Tools used by Engineers. By C.
P. B. SHELLEY, M.I.C.E. With an additional Chapter on Milling by R. R.
LISTER. With 323 Woodcuts. Fcp. 8vo., 5_s._




                     MINERALOGY, METALLURGY, ETC.


_BAUERMAN._--Works by HILARY BAUERMAN, F.G.S.

     SYSTEMATIC MINERALOGY. With 373 Woodcuts and Diagrams. Fcp.
     8vo., 6_s._

     DESCRIPTIVE MINERALOGY. With 236 Woodcuts and Diagrams. Fcp.
     8vo., 6_s._

_GORE._--THE ART OF ELECTRO-METALLURGY, including all known Processes
of Electro-Deposition. By G. GORE, LL.D., F.R.S. With 56 Woodcuts.
Fcp. 8vo., 6_s._

_HUNTINGTON AND McMILLAN_--METALS: their Properties and Treatment. By
A. K. HUNTINGTON, Professor of Metallurgy in King's College, London,
and W. G. McMillan, Lecturer on Metallurgy in Mason's College,
Birmingham. With 122 Illustrations. Fcp. 8vo., 7_s._ 6_d._

_RHEAD._--METALLURGY. An Elementary Text-Book. By E. C. RHEAD,
Lecturer on Metallurgy at the Municipal Technical School, Manchester.
With 94 Illustrations. Fcp. 8vo., 3_s._ 6_d._

_RUTLEY._--THE STUDY OF ROCKS: an Elementary Text-book of Petrology.
BY F. RUTLEY, F.G.S. With 6 Plates and 88 Woodcuts. Fcp. 8vo., 4_s._
6_d._




                      ASTRONOMY, NAVIGATION, ETC.


_ABBOTT._--ELEMENTARY THEORY OF THE TIDES: the Fundamental Theorems
Demonstrated without Mathematics and the Influence on the Length of
the Day Discussed. By T. K. ABBOTT, B.D., Fellow and Tutor, Trinity
College, Dublin. Crown 8vo., 2_s._

_BALL._--Works by Sir ROBERT S. BALL, LL.D., F.R.S.

     ELEMENTS OF ASTRONOMY. With 130 Figures and Diagrams. Fcp.
     8vo., 6_s._ 6_d._

     A CLASS-BOOK OF ASTRONOMY. With 41 Diagrams. Fcp. 8vo.,
     1_s._ 6_d._

_DE CAMPIGNEULLES._--OBSERVATIONS TAKEN AT DUMRAON, BEHAR, INDIA,
during the Eclipse of the 22nd January, 1898, by a Party of Jesuit
Fathers of the Western Bengal Mission. By the Rev. V. DE
CAMPIGNEULLES, S.J. With 14 Plates. 4to., 10_s._ 6_d._ net.

_GILL._--TEXT-BOOK ON NAVIGATION AND NAUTICAL ASTRONOMY. By J. GILL,
F.R.A.S., late Head Master of the Liverpool Corporation Nautical
College. 8vo., 10_s._ 6_d._

_HERSCHEL._--OUTLINES OF ASTRONOMY. By Sir JOHN F. W. HERSCHEL, Bart.,
K.H., etc. With 9 Plates and numerous Diagrams. 8vo., 12_s._

_JORDAN._--ESSAYS IN ILLUSTRATION OF THE ACTION OF ASTRAL GRAVITATION
IN NATURAL PHENOMENA. By WILLIAM LEIGHTON JORDAN. With Diagrams. 8vo.,
9_s._

_LAUGHTON._--AN INTRODUCTION TO THE PRACTICAL AND THEORETICAL STUDY OF
NAUTICAL SURVEYING. By JOHN KNOX LAUGHTON, M.A., F.R.A.S. With 35
Diagrams. Crown 8vo., 6_s._

_LOWELL._--MARS. By PERCIVAL LOWELL, Fellow American Academy, Member
Royal Asiatic Society, Great Britain and Ireland, etc. With 24 Plates.
8vo., 12_s._ 6_d._

_MARTIN._--NAVIGATION AND NAUTICAL ASTRONOMY. Compiled by Staff
Commander W. R. MARTIN, R.N. Royal 8vo., 18_s._

_MERRIFIELD._--A TREATISE ON NAVIGATION. For the Use of Students. By
J. MERRIFIELD, LL.D., F.R.A.S., F.M.S. With Charts and Diagrams. Crown
8vo., 5_s._

_PARKER._--ELEMENTS OF ASTRONOMY. With Numerous Examples and
Examination Papers. By GEORGE W. PARKER, M.A., of Trinity College,
Dublin. With 84 Diagrams. 8vo., 5_s._ 6_d._ net.

_WEBB._--CELESTIAL OBJECTS FOR COMMON TELESCOPES. By the Rev. T. W.
WEBB, M.A., F.R.A.S. Fifth Edition, Revised and greatly Enlarged by
the Rev. T. E. ESPIN, M.A., F.R.A.S. (Two Volumes.) Vol. I., with
Portrait and a Reminiscence of the Author, 2 Plates, and numerous
Illustrations. Crown 8vo., 6_s._ Vol. II., with numerous
Illustrations. Crown 8vo., 6_s._ 6_d._




                     WORKS BY RICHARD A. PROCTOR.


THE MOON: Her Motions, Aspect, Scenery, and Physical Condition. With
many Plates and Charts, Wood Engravings, and 2 Lunar Photographs.
Crown 8vo., 3_s._ 6_d._

OTHER WORLDS THAN OURS: the Plurality of Worlds Studied Under the
Light of Recent Scientific Researches. With 14 Illustrations; Map,
Charts, etc. Crown 8vo., 3_s._ 6_d._

OUR PLACE AMONG INFINITIES: a Series of Essays contrasting our Little
Abode in Space and Time with the Infinities around us. Crown 8vo.,
3_s._ 6_d._

MYTHS AND MARVELS OF ASTRONOMY. Crown 8vo., 3_s._ 6_d._

LIGHT SCIENCE FOR LEISURE HOURS: Familiar Essays on Scientific
Subjects, Natural Phenomena, etc. Vols. I. and II. Crown 8vo., 5_s._
each. Vol. I. Cheap Edition. Crown 8vo., 3_s._ 6_d._

THE ORBS AROUND US; Essays on the Moon and Planets, Meteors and
Comets, the Sun and Coloured Pairs of Suns. Crown 8vo., 3_s._ 6_d._

THE EXPANSE OF HEAVEN: Essays on the Wonders of the Firmament. Crown
8vo., 3_s._ 6_d._

OTHER SUNS THAN OURS: a Series of Essays on Suns--Old, Young, and
Dead. With other Science Gleanings. Two Essays on Whist, and
Correspondence with Sir John Herschel. With 9 Star-Maps and Diagrams.
Crown 8vo., 3_s._ 6_d._

HALF-HOURS WITH THE TELESCOPE: a Popular Guide to the Use of the
Telescope as a means of Amusement and Instruction. With 7 Plates. Fcp.
8vo., 2_s._ 6_d._

NEW STAR ATLAS FOR THE LIBRARY, the School, and the Observatory, in
Twelve Circular Maps (with Two Index-Plates). With an Introduction on
the Study of the Stars. Illustrated by 9 Diagrams. Cr. 8vo., 5_s._

THE SOUTHERN SKIES: a Plain and Easy Guide to the Constellations of
the Southern Hemisphere. Showing in 12 Maps the position of the
principal Star-Groups night after night throughout the year. With an
Introduction and a separate Explanation of each Map. True for every
Year. 4to., 5_s._

HALF-HOURS WITH THE STARS: a Plain and Easy Guide to the Knowledge of
the Constellations. Showing in 12 Maps the position of the principal
Star-Groups night after night throughout the year. With Introduction
and a separate Explanation of each Map. True for every Year. 4to.,
3_s._ 6_d._

LARGER STAR ATLAS FOR OBSERVERS AND STUDENTS. In Twelve Circular Maps,
showing 6000 Stars, 1500 Double Stars, Nebulæ, etc. With 2
Index-Plates. Folio, 15_s._

THE STARS IN THEIR SEASONS: an Easy Guide to a Knowledge of the
Star-Groups. In 12 Large Maps. Imperial 8vo., 5_s._

ROUGH WAYS MADE SMOOTH. Familiar Essays on Scientific Subjects. Crown
8vo., 3_s._ 6_d._

PLEASANT WAYS IN SCIENCE. Crown 8vo., 3_s._ 6_d._

NATURE STUDIES. By R. A. PROCTOR, GRANT ALLEN, A. WILSON, T. FOSTER,
and E. CLODD. Crown 8vo., 3_s._ 6_d._

LEISURE READINGS. By R. A. PROCTOR, E. CLODD, A. WILSON, T. FOSTER,
and A. C. RANYARD. Crown 8vo., 3_s._ 6_d._




                       PHYSIOGRAPHY AND GEOLOGY.


_BIRD._--Works by CHARLES BIRD, B.A.

     ELEMENTARY GEOLOGY. With Geological Map of the British
     Isles, and 247 Illustrations. Crown 8vo., 2_s._ 6_d._

     ADVANCED GEOLOGY. A Manual for Students in Advanced Classes
     and for General Readers. With over 300 Illustrations, a
     Geological Map of the British Isles (coloured), and a set of
     Questions for Examination. Crown 8vo., 7_s._ 6_d._

_GREEN._--PHYSICAL GEOLOGY FOR STUDENTS AND GENERAL READERS. By A. H.
GREEN, M.A., F.G.S. With 236 Illustrations. 8vo., 21_s._

_MORGAN._--ELEMENTARY PHYSIOGRAPHY. Treated Experimentally. By ALEX.
MORGAN, M.A., D.Sc., F.R.S.E., Lecturer in Mathematics and Science,
Church of Scotland Training College, Edinburgh. With 4 Maps and 243
Diagrams. Crown 8vo., 2_s._ 6_d._

_THORNTON._--Works by J. THORNTON, M.A.

     ELEMENTARY PRACTICAL PHYSIOGRAPHY.
       Part I. With 215 Illustrations. Crown 8vo., 2_s._ 6_d._
       Part II. With 98 Illustrations. Crown 8vo., 2_s._ 6_d._

     ELEMENTARY PHYSIOGRAPHY: an Introduction to the Study of
     Nature. With 13 Maps and 295 Illustrations. With Appendix on
     Astronomical Instruments and Measurements. Crown 8vo., 2_s._
     6_d._

     ADVANCED PHYSIOGRAPHY. With 6 Maps and 203 Illustrations.
     Crown 8vo., 4_s._ 6_d._




                 NATURAL HISTORY AND GENERAL SCIENCE.


_BEDDARD._--THE STRUCTURE AND CLASSIFICATION OF BIRDS. By FRANK E.
BEDDARD, M.A., F.R.S., Prosector and Vice-Secretary of the Zoological
Society of London. With 252 Illustrations. 8vo., 21_s._ net.

_FURNEAUX._--Works by WILLIAM FURNEAUX, F.R.G.S.

     THE OUTDOOR WORLD; or, The Young Collector's Hand-book. With
     18 Plates, 16 of which are coloured, and 549 Illustrations
     in the Text. Crown 8vo., 6_s._ net.

     LIFE IN PONDS AND STREAMS. With 8 Coloured Plates and 331
     Illustrations in the Text. Crown 8vo., 6_s._ net.

     BUTTERFLIES AND MOTHS (British). With 12 Coloured Plates and
     241 Illustrations in the Text. Crown 8vo., 6_s._ net.

_HUDSON._--BRITISH BIRDS. By W. H. HUDSON, C.M.Z.S. With 8 Coloured
Plates from Original Drawings by A. THORBURN, and 8 Plates and 100
Figures by C. E. LODGE, and 3 Illustrations from Photographs. Crown
8vo., 6_s._ net.

_NANSEN._--THE NORWEGIAN NORTH POLAR EXPEDITION, 1893-1896: Scientific
Results. Edited by FRIDTJOF NANSEN. Volume I. With 44 Plates and
numerous Illustrations in the Text. Demy 4to, 40_s._ net.

     CONTENTS: 1. COLIN ARCHER: The _Fram_--2. J. F. POMPECKJ:
     The Jurassic Fauna of Cape Flora. With a Geological Sketch
     of Cape Flora and its Neighbourhood by FRIDTJOF NANSEN--3.
     A. G. NATHORST: Fossil Plants from Franz Josef Land--4. R.
     COLLETT and F. NANSEN: An Account of the Birds--5. G. O.
     SARS: Crustacea.

    *** _The aim of this Report (which will be published in
    English only) is to give, in a series of separate Memoirs, a
    complete account of the Scientific Results of the Norwegian
    Polar Expedition, 1893-1896. The whole work is estimated to
    form five or six Quarto Volumes, which it is hoped will be
    finished in the course of about two years._

_STANLEY._--A FAMILIAR HISTORY OF BIRDS. By E. STANLEY, D.D., formerly
Bishop of Norwich. With 160 Illustrations. Crown 8vo, 3_s._ 6_d._




                    MANUFACTURES, TECHNOLOGY, ETC.


_BELL._--JACQUARD WEAVING AND DESIGNING. By F. T. BELL. With 199
Diagrams. 8vo., 12_s._ net.

_CALDER._--THE PREVENTION OF FACTORY ACCIDENTS: being an Account of
Manufacturing Industry and Accident, and a Practical Guide to the Law
on the Safe-guarding, Safe-working and Safe-construction of Factory
Machinery, Plant and Premises. By JOHN CALDER, sometime Her Majesty's
Inspector of Factories for the North of Scotland. With 20 Tables and
124 Illustrations. Crown 8vo., 7_s._ 6_d._ net.

_LUPTON._--MINING. An Elementary Treatise on the Getting of Minerals.
By ARNOLD LUPTON, M.I.C.E., F.G.S., etc. With 596 Diagrams and
Illustrations. Crown 8vo., 9_s._ net.

_MORRIS AND WILKINSON._--THE ELEMENTS OF COTTON SPINNING. By JOHN
MORRIS and F. WILKINSON. With a Preface by Sir B. A. DOBSON, C.E.,
M.I.M.E. With 169 Diagrams and Illustrations. Crown 8vo., 7_s._ 6_d._
net.

_SHARP._--BICYCLES AND TRICYCLES: an Elementary Treatise on their
Design and Construction. With Examples and Tables. By ARCHIBALD SHARP,
B.Sc. With 565 Illustrations and Diagrams. Cr. 8vo., 15_s._

_TAYLOR._--COTTON WEAVING AND DESIGNING. By JOHN T. TAYLOR. With 373
Diagrams. Crown 8vo., 7_s._ 6_d._ net.

_WATTS._--AN INTRODUCTORY MANUAL FOR SUGAR GROWERS. By FRANCIS WATTS,
F.C.S., F.I.C. With 20 Illustrations. Crown 8vo., 6_s._




                         HEALTH AND HYGIENE.


_ASHBY._--HEALTH IN THE NURSERY. By HENRY ASHBY, M.D., F.R.C.P.,
Physician to the Manchester Children's Hospital, and Lecturer on the
Diseases of Children at the Owens College. With 25 Illustrations.
Crown 8vo., 3_s._ 6_d._

_BUCKTON._--HEALTH IN THE HOUSE; Twenty-five Lectures on Elementary
Physiology. By Mrs. C. M. BUCKTON. With 41 Woodcuts and Diagrams.
Crown 8vo., 2_s._

_CORFIELD._--THE LAWS OF HEALTH. By W. H. CORFIELD, M.A., M.D. Fcp.
8vo., 1_s._ 6_d._

_NOTTER AND FIRTH._--Works by J. L. NOTTER, M.A., M.D., and R. H.
FIRTH, F.R.C.S.

     HYGIENE. With 95 Illustrations. Crown 8vo., 3_s._ 6_d._

     PRACTICAL DOMESTIC HYGIENE. With 83 Illustrations. Crown
     8vo., 2_s._ 6_d._

_POORE._--Works by GEORGE VIVIAN POORE, M.D.

     ESSAYS ON RURAL HYGIENE. Crown 8vo., 6_s._ 6_d._

     THE DWELLING-HOUSE. With 36 Illustrations. Crown 8vo., 3_s._
     6_d._

_WILSON._--A MANUAL OF HEALTH-SCIENCE: adapted for use in Schools and
Colleges. By ANDREW WILSON, F.R.S.E., F.L.S., etc. With 74
Illustrations. Crown 8vo., 2_s._ 6_d._




                         MEDICINE AND SURGERY.


_ASHBY AND WRIGHT._--THE DISEASES OF CHILDREN, MEDICAL AND SURGICAL.
By HENRY ASHBY, M.D., Lond., F.R.C.P., Physician to the General
Hospital for Sick Children, Manchester; and G. A. WRIGHT, B.A., M.B.
Oxon., F.R.C.S., Eng., Assistant-Surgeon to the Manchester Royal
Infirmary, and Surgeon to the Children's Hospital. Enlarged and
Improved Edition. With 192 Illustrations. 8vo., 25_s._

_BENNETT._--Works by WILLIAM H. BENNETT, F.R.C.S., Surgeon to St.
George's Hospital; Member of the Board of Examiners, Royal College of
Surgeons of England.

     CLINICAL LECTURES ON VARICOSE VEINS OF THE LOWER
     EXTREMITIES. With 3 Plates. 8vo., 6_s._

     ON VARICOCELE; A PRACTICAL TREATISE. With 4 Tables and a
     Diagram. 8vo., 5_s._

     CLINICAL LECTURES ON ABDOMINAL HERNIA: chiefly in relation
     to Treatment, including the Radical Cure. With 12 Diagrams
     in the Text. 8vo., 8_s._ 6_d._

     ON VARIX, ITS CAUSES AND TREATMENT, WITH ESPECIAL REFERENCE
     TO THROMBOSIS: an Address delivered at the Inaugural Meeting
     of the Nottingham Medico-Chirurgical Society, Session
     1898-99. 8vo., 3_s._ 6_d._

_BENTLEY._--A TEXT-BOOK OF ORGANIC MATERIA MEDICA. Comprising a
Description of the Vegetable and Animal Drugs of the British
Pharmacopoeia, with some others in common use. Arranged
Systematically, and Especially Designed for Students. By ROBERT
BENTLEY, M.R.C.S. Eng., F.L.S. With 62 Illustrations on Wood. Crown
8vo., 7_s._ 6_d._

_BRODIE._--THE ESSENTIALS OF EXPERIMENTAL PHYSIOLOGY. For the Use of
Students. By T. G. BRODIE, M.D., Lecturer on Physiology, St. Thomas's
Hospital Medical School. With 2 Plates and 177 Illustrations in the
Text. Crown 8vo., 6_s._ 6_d._

_CABOT._--Works by RICHARD C. CABOT, M.D., Physician to Out-patients,
Massachusetts General Hospital.

     A GUIDE TO THE CLINICAL EXAMINATION OF THE BLOOD FOR
     DIAGNOSTIC PURPOSES. With 3 Coloured Plates and 28
     Illustrations in the Text. 8vo., 16_s._

     THE SERUM DIAGNOSIS OF DISEASE. With 31 Temperature Charts
     and 9 Illustrations. Royal 8vo., 7_s._ 6_d._

_CELLI._--MALARIA, ACCORDING TO THE NEW RESEARCHES. By Prof. ANGELO
CELLI, Director of the Institute of Hygiene, University of Rome.
Translated from the Second Italian Edition by JOHN JOSEPH EYRE,
M.R.C.P., L.R.C.S. Ireland, D.P.H. Cambridge. With an Introduction by
Dr. PATRICK MANSON, Medical Adviser to the Colonial Office. 8vo.,
10_s._ 6_d._

_CHEYNE AND BURGHARD._--A MANUAL OF SURGICAL TREATMENT. By W. WATSON
CHEYNE, M.B., F.R.C.S., F.R.S., Professor of Surgery in King's
College, London, Surgeon to King's College Hospital, etc.; and F. F.
BURGHARD, M.D. and M.S., F.R.C.S., Teacher of Practical Surgery in
King's College, London, Surgeon to King's College, Hospital (Lond.),
etc.

     Part I. The Treatment of General Surgical Diseases,
     including Inflammation, Suppuration, Ulceration, Gangrene,
     Wounds and their Complications, Infective Diseases and
     Tumours; the Administration of Anæsthetics. With 66
     Illustrations. Royal 8vo., 10_s._ 6_d._               [Ready.

     Part II. The Treatment of the Surgical Affections of the
     Tissues, including the Skin and Subcutaneous Tissues, the
     Nails, the Lymphatic Vessels and Glands, the Fasciæ, Bursæ,
     Muscles, Tendons and Tendon-sheaths, Nerves, Arteries and
     Veins. Deformities. With 141 Illustrations. Royal 8vo.,
     14_s._                                                [Ready.

     Part III. The Treatment of the Surgical Affections of the
     Bones. Amputations. With 100 Illustrations. Royal 8vo.,
     12_s._

     Part IV. The Treatment of the Surgical Affections of the
     Joints (including Excisions) and the Spine. With 138
     Illustrations. Royal 8vo., 14_s._

                  _Other Parts are in preparation._

_CLARKE._--Works by J. JACKSON CLARKE, M.B. Lond., F.R.C.S., Assistant
Surgeon at the North-west London and City Orthopædic Hospitals, etc.

     SURGICAL PATHOLOGY AND PRINCIPLES. With 194 Illustrations.
     Crown 8vo., 10_s._ 6_d._

     POST-MORTEM EXAMINATIONS IN MEDICO-LEGAL AND ORDINARY CASES.
     With Special Chapters on the Legal Aspects of Post-mortems,
     and on Certificates of Death. Fcp. 8vo., 2_s._ 6_d._

_COATS._--A MANUAL OF PATHOLOGY. By JOSEPH COATS, M.D., late Professor
of Pathology in the University of Glasgow. Fourth Edition. Revised
throughout and Edited by LEWIS R. SUTHERLAND, M. D., Professor of
Pathology, University of St. Andrews. With 490 Illustrations. 8vo.,
31_s._ 6_d._

_COOKE._--Works by THOMAS COOK, F.R.C.S. Eng., B.A., B.Sc., M.D.,
Paris.

    TABLETS OF ANATOMY. Being a Synopsis of Demonstrations given
    in the Westminster Hospital Medical School. Eleventh Edition
    in Three Parts, thoroughly brought up to date, and with over
    700 Illustrations from all the best Sources, British and
    Foreign. Post 4to.
      Part I. The Bones. 7_s._ 6_d._ net.
      Part II. Limbs, Abdomen, Pelvis. 10_s._ 6_d._ net.
      Part III. Head and Neck, Thorax, Brain. 10_s._ 6_d._ net.

    APHORISMS IN APPLIED ANATOMY AND OPERATIVE SURGERY. Including
    100 Typical _vivâ voce_ Questions on Surface Marking, etc.
    Crown 8vo., 3_s._ 6_d._

    DISSECTION GUIDES. Aiming at Extending and Facilitating such
    Practical work in Anatomy as will be specially useful in
    connection with an ordinary Hospital Curriculum. 8vo., 10_s._
    6_d._

_CURTIS._--THE ESSENTIALS OF PRACTICAL BACTERIOLOGY: An Elementary
Laboratory Book for Students and Practitioners. By H. J. CURTIS, B.S.
and M.D. Lond., F.R.C.S., late Surgical Registrar, University College
Hospital; formerly Assistant to the Professor of Pathology, University
College, London. With 133 Illustrations. 8vo., 9_s._

_DAKIN._--A HANDBOOK OF MIDWIFERY. By WILLIAM RADFORD DAKIN, M.D.,
F.R.C.P., Obstetric Physician and Lecturer on Midwifery at St.
George's Hospital, etc. With 394 Illustrations. Large crown 8vo.,
18_s._

_DICKINSON._--Works by W. HOWSHIP DICKINSON, M.D. Cantab., F.R.C.P.

     ON RENAL AND URINARY AFFECTIONS. With 12 Plates and 122
     Woodcuts. Three Parts. 8vo., £3 4_s._ 6_d._

     THE TONGUE AS AN INDICATION OF DISEASE; being the Lumleian
     Lectures delivered March, 1888. 8vo., 7_s._ 6_d._

     OCCASIONAL PAPERS ON MEDICAL SUBJECTS, 1855-1896. 8vo.,
     12_s._

     MEDICINE OLD AND NEW. An Address Delivered on the Occasion
     of the Opening of the Winter Session, 1899-1900, at St.
     George's Hospital Medical School, on 2nd October, 1899.
     Crown 8vo., 2_s._ 6_d._

_DUCKWORTH._--Works by SIR DYCE DUCKWORTH, M.D., LL.D., Fellow and
Treasurer of the Royal College of Physicians, etc.

     THE SEQUELS OF DISEASE: being the Lumleian Lectures, 1896.
     8vo., 10_s._ 6_d._

     THE INFLUENCE OF CHARACTER AND RIGHT JUDGMENT IN MEDICINE:
     the Harveian Oration, 1898. Post 4to. 2_s._ 6_d._

_ERICHSEN._--THE SCIENCE AND ART OF SURGERY; a Treatise on Surgical
Injuries, Diseases, and Operations. By Sir JOHN ERIC ERICHSEN, Bart.,
F.R.S., LL.D. Edin., Hon. M.Ch. and F.R.C.S. Ireland. Illustrated by
nearly 1000 Engravings on Wood. 2 vols. Royal 8vo., 48_s._

_FOWLER AND GODLEE._--THE DISEASES OF THE LUNGS. By JAMES KINGSTON
FOWLER, M.A., M.D., F.R.C.P., Physician to the Middlesex Hospital and
to the Hospital for Consumption and Diseases of the Chest, Brompton,
etc.; and RICKMAN JOHN GODLEE, M.S., F.R.C.S., Fellow and Professor of
Clinical Surgery, University College, London, etc.; With 160
Illustrations. 8vo., 25_s._

_GARROD._--Works by SIR ALFRED BARING GARROD, M.D., F.R.S., etc.

     A TREATISE ON GOUT AND RHEUMATIC GOUT (RHEUMATOID
     ARTHRITIS). With 6 Plates, comprising 21 Figures (14
     Coloured), and 27 Illustrations engraved on Wood. 8vo.,
     21_s._

     THE ESSENTIALS OF MATERIA MEDICA AND THERAPEUTICS. Crown
     8vo., 12_s._ 6_d._

_GOODSALL AND MILES._--DISEASES OF THE ANUS AND RECTUM. By D. H.
GOODSALL, F.R.C.S., Senior Surgeon, Metropolitan Hospital; Senior
Surgeon (late House Surgeon), St. Mark's Hospital; and W. ERNEST
MILES, F.R.C.S., Assistant Surgeon to the Cancer Hospital, Assistant
Surgeon to the Gordon Hospital, etc. With Illustrations. (In Two
Parts.) Part I. 8vo., 7_s._ 6_d._ net.

_GRAY._--ANATOMY, DESCRIPTIVE AND SURGICAL. By HENRY GRAY, F.R.S.,
late Lecturer on Anatomy at St. George's Hospital. The Fourteenth
Edition, re-edited by T. PICKERING PICK, Surgeon to St. George's
Hospital, Inspector of Anatomy in England and Wales, late Member of
the Court of Examiners, Royal College of Surgeons of England. With 705
large Woodcut Illustrations, a large proportion of which are Coloured,
the Arteries being coloured red, the Veins blue, and the Nerves
yellow. The attachments of the muscles to the bones, in the section on
Osteology, are also shown in coloured outline. Royal 8vo., 36_s._

_HALLIBURTON._--Works by W. D. HALLIBURTON, M.D., F.R.S., F.R.C.P.,
Professor of Physiology in King's College, London.

    A TEXT-BOOK OF CHEMICAL PHYSIOLOGY AND PATHOLOGY. With 104
    Illustrations. 8vo., 28_s._

    ESSENTIALS OF CHEMICAL PHYSIOLOGY. With 77 Illustrations.
    8vo., 5_s._

_LANG._--THE METHODICAL EXAMINATION OF THE EYE. Being Part I. of a
Guide to the Practice of Ophthalmology for Students and Practitioners.
By WILLIAM LANG, F.R.C.S. Eng., Surgeon to the Royal London Ophthalmic
Hospital, Moorfields, etc. With 15 Illustrations. Crown 8vo., 3_s._
6_d._

_LIVEING._--HANDBOOK ON DISEASES OF THE SKIN. With especial reference
to Diagnosis and Treatment. By ROBERT LIVEING, M.A. and M.D., Cantab.,
F.R.C.P. Lond., etc., Physician to the Department for Diseases of the
Skin at the Middlesex Hospital, etc. Fcp. 8vo., 5_s._

_LUFF._--TEXT-BOOK OF FORENSIC MEDICINE AND TOXICOLOGY. By ARTHUR P.
LUFF, M.D., B.Sc. (Lond.), Physician in Charge of Out-Patients and
Lecturer on Medical Jurisprudence and Toxicology in St. Mary's
Hospital. With 13 full-page Plates (1 in colours) and 33 Illustrations
in the Text. 2 vols. Crown 8vo., 24_s._

_NEWMAN._--ON THE DISEASES OF THE KIDNEY AMENABLE TO SURGICAL
TREATMENT. Lectures to Practitioners. By DAVID NEWMAN, M.D., Surgeon
to the Western Infirmary Out-Door Department; Pathologist and Lecturer
on Pathology at the Glasgow Royal Infirmary; Examiner in Pathology in
the University of Glasgow; Vice-President, Glasgow Pathological and
Clinical Society. 8vo., 8_s._

_PICK._--SURGERY: a Treatise for Students and Practitioners. By T.
PICKERING PICK, Consulting Surgeon to St. George's Hospital; Senior
Surgeon to the Victoria Hospital for Children; H.M. Inspector of
Anatomy in England and Wales. With 441 Illustrations. Medium 8vo.,
25_s._

_POOLE._--COOKERY FOR THE DIABETIC. By W. H. and Mrs. POOLE. With
Preface by Dr. PAVY. Fcap. 8vo., 2_s._ 6_d._

_QUAIN._--A DICTIONARY OF MEDICINE; Including General Pathology,
General Therapeutics, Hygiene, and the Diseases of Women and Children.
By Various Writers. Edited by RICHARD QUAIN, Bart., M.D. Lond., LL.D.
Edin. (Hon.) F.R.S., Physician Extraordinary to H.M. the Queen, etc.
Assisted by FREDERICK THOMAS ROBERTS, M.D. Lond., B.Sc., Fellow of the
Royal College of Physicians, Fellow of University College, etc.; and
J. MITCHELL BRUCE, M.A. Abdn., M.D. Lond., Fellow of the Royal College
of Physicians of London, etc. 2 Vols. Medium 8vo., 40_s._ net.

_QUAIN._--QUAIN'S (JONES) ELEMENTS OF ANATOMY. The Tenth Edition.
Edited by EDWARD ALBERT SCHÄFER, F.R.S., Professor of Physiology in
the University of Edinburgh; and GEORGE DANCER THANE, Professor of
Anatomy in University College, London.

  *** The several parts of this work form COMPLETE TEXT-BOOKS OF
  THEIR RESPECTIVE SUBJECTS.

    VOL. I., PART I. EMBRYOLOGY. By E. A. SCHÄFER, F.R.S. With
    200 Illustrations. Royal 8vo., 9_s._

    VOL. I., PART II. GENERAL ANATOMY OR HISTOLOGY By E. A.
    SCHÄFER, F.R.S. With 291 Illustrations. Royal 8vo., 12_s._
    6_d._

    VOL. II., PART I. OSTEOLOGY--ARTHROLOGY. By G. D. THANE. With
    224 Illus. Royal 8vo., 11_s._

    VOL. II., PART II. MYOLOGY--ANGEIOLOGY. By G. D. THANE. With
    199 Illustrations. Royal 8vo., 16_s._

    VOL. III., PART I. THE SPINAL CORD AND BRAIN. By E. A.
    SCHÄFER, F.R.S. With 139 Illustrations. Royal 8vo., 12_s._
    6_d._

    VOL. III., PART II. THE NERVES. By G. D. THANE. With 102
    Illustrations. Royal 8vo., 9_s._

    VOL III., PART III. THE ORGANS OF THE SENSES. By E. A.
    SCHÄFER, F.R.S. With 178 Illustrations. Royal 8vo., 9_s._

    VOL. III, PART IV. SPLANCHNOLOGY. By E. A SCHÄFER, F.R.S and
    JOHNSON SYMINGTON, M.D. With 337 Illustrations. Royal 8vo.,
    16_s._

    APPENDIX. SUPERFICIAL AND SURGICAL ANATOMY. By Professor G.
    D. THANE and Professor R. J. GODLEE, M.S. With 29
    Illustrations. Royal 8vo., 6_s._ 6_d._

_SCHÄFER._--THE ESSENTIALS OF HISTOLOGY. Descriptive and Practical.
For the Use of Students. By E. A. SCHÄFER, F.R.S., Professor of
Physiology in the University of Edinburgh; Editor of the Histological
Portion of Quain's 'Anatomy'. Illustrated by nearly 400 Figures. Fifth
Edition, Revised and Enlarged. 8vo., 8_s._ (Interleaved, 10_s._ 6_d._)

_SCHENK._--MANUAL OF BACTERIOLOGY. For Practitioners and Students.
With especial reference to Practical Methods. By Dr. S. L. SCHENK,
Professor (Extraordinary) in the University of Vienna. Translated from
the German, with an Appendix, by W. R. DAWSON, B.A., M.D., Univ. Dub.;
late University Travelling Prizeman in Medicine. With 100
Illustrations, some of which are coloured. 8vo., 10_s._ net.

_SMALE AND COLYER._ DISEASES AND INJURIES OF THE TEETH, including
Pathology and Treatment: a Manual of Practical Dentistry for Students
and Practitioners. By MORTON SMALE, M.R.C.S., L.S.A., L.D.S., Dental
Surgeon to St. Mary's Hospital, Dean of the School, Dental Hospital of
London, etc.; and J. F. COLYER, L.R.C.P., M.R.C.S., L.D.S., Assistant
Dental Surgeon to Charing Cross Hospital, and Assistant Dental Surgeon
to the Dental Hospital of London. With 334 Illustrations. Large crown
8vo., 15_s._

_SMITH_ (_H. F._). THE HANDBOOK FOR MIDWIVES. By HENRY FLY SMITH,
B.A., M.B. Oxon., M.R.C.S. 41 Woodcuts. Cr. 8vo., 5_s._

_STEVENSON._--WOUNDS IN WAR: the Mechanism of their Production and
their Treatment. By Surgeon-Colonel W. F. STEVENSON (Army Medical
Staff), A.B., M.B., M.Ch. Dublin University, Professor of Military
Surgery, Army Medical School, Netley. With 86 Illustrations. 8vo.,
18_s._

_TAPPEINER._--INTRODUCTION TO CHEMICAL METHODS OF CLINICAL DIAGNOSIS.
By Dr. H. TAPPEINER, Professor of Pharmacology and Principal of the
Pharmacological Institute of the University of Munich. Translated by
EDMOND J. MCWEENEY, M.A., M.D. (Royal Univ. of Ireland), L.R.C.P.I.,
etc. Crown 8vo. 3_s._ 6_d._

_TIRARD._--DIPHTHERIA AND ANTITOXIN. By NESTOR TIRARD, M.D. Lond.,
Fellow of the Royal College of Physicians; Fellow of King's College,
London; Professor of Materia Medica and Therapeutics at King's
College; Physician to King's College Hospital; and Senior Physician to
the Evelina Hospital for Sick Children. 8vo., 7_s._ 6_d._

_WALLER._--Works by AUGUSTUS D. WALLER, M.D., Lecturer on Physiology
at St. Mary's Hospital Medical School, London; late External Examiner
at the Victorian University.

     AN INTRODUCTION TO HUMAN PHYSIOLOGY. Third Edition, Revised.
     With 314 Illustrations. 8vo., 18_s._

     LECTURES ON PHYSIOLOGY. First Series. On Animal Electricity.
     8vo., 5_s._ net.

     EXERCISES IN PRACTICAL PHYSIOLOGY. Part I. Elementary
     Physiological Chemistry. By AUGUSTUS D. WALLER and W. LEGGE
     SYMES. 8vo., 1_s._ net. Part II. in the press. Part III.
     Physiology of the Nervous System; Electro-Physiology. 8vo.,
     2_s._ 6_d._ net.

_WEICHSELBAUM._--THE ELEMENTS OF PATHOLOGICAL HISTOLOGY. With Special
Reference to Practical Methods. By Dr. ANTON WEICHSELBAUM, Professor
of Pathology in the University of Vienna. Translated by W. R. DAWSON,
M.D. (Dub.), Demonstrator of Pathology in the Royal College of
Surgeons, Ireland, late Medical Travelling Prizeman of Dublin
University, etc. With 221 Figures, partly in Colours, a
Chromo-lithographic Plate, and 7 Photographic Plates. Royal 8vo.,
21_s._ net.

_WILKS AND MOXON._--LECTURES ON PATHOLOGICAL ANATOMY. By Sir SAMUEL
WILKS, Bart., M.D., F.R.S., President of the Royal College of
Physicians, and Physician Extraordinary to H. M. the Queen, and the
late WALTER MOXON, M.D., F.R.C.P., Physician to, and some time
Lecturer on Pathology at, Guy's Hospital. Third Edition, thoroughly
Revised. By Sir SAMUEL WILKS, Bart., M.D., LL.D., F.R.S. 8vo., 18_s._




                       VETERINARY MEDICINE, ETC.


_STEEL._--Works by JOHN HENRY STEEL, F.R.C.V.S., F.Z.S., A.V.D., late
Professor of Veterinary Science and Principal of Bombay Veterinary
College.

     A TREATISE ON THE DISEASES OF THE DOG; being a Manual of
     Canine Pathology. Especially adapted for the use of
     Veterinary Practitioners and Students. With 88
     Illustrations. 8vo., 10_s._ 6_d._

     A TREATISE ON THE DISEASES OF THE OX; being a Manual of
     Bovine Pathology. Especially adapted for the use of
     Veterinary Practitioners and Students. With 2 Plates and 117
     Woodcuts. 8vo., 15_s._

     A TREATISE ON THE DISEASES OF THE SHEEP; being a Manual of
     Ovine Pathology for the use of Veterinary Practitioners and
     Students. With Coloured Plate and 99 Woodcuts. 8vo., 12_s._

     OUTLINES OF EQUINE ANATOMY; a Manual for the use of
     Veterinary Students in the Dissecting Room. Crown 8vo.,
     7_s._ 6_d._

_FITZWYGRAM._--HORSES AND STABLES. By Major-General Sir F. FITZWYGRAM,
Bart. With 56 pages of Illustrations. 8vo. 2_s._ 6_d._ net.

_SCHREINER._--THE ANGORA GOAT. By S. C. CRONWRIGHT SCHREINER. With 26
Illustrations. 8vo., 10_s._ 6_d._

_YOUATT._--Works by WILLIAM YOUATT.

     THE HORSE. With 52 Wood Engravings. 8vo., 7_s._ 6_d._

     THE DOG. With 33 Wood Engravings. 8vo., 6_s._




            PHYSIOLOGY, BIOLOGY, BACTERIOLOGY, AND ZOOLOGY.
                  (And see _MEDICINE AND SURGERY_.)


_ASHBY._--NOTES ON PHYSIOLOGY FOR THE USE OF STUDENTS PREPARING FOR
EXAMINATION. By HENRY ASHBY, M.D. Lond., F.R.C.P., Physician to the
General Hospital for Sick Children, Manchester; formerly Demonstrator
of Physiology, Liverpool School of Medicine. With 148 Illustrations.
18mo., 5_s._

_BARNETT._--THE MAKING OF THE BODY: a Children's Book on Anatomy and
Physiology. By Mrs. S. A. BARNETT. With 113 Illustrations. Crown 8vo.,
1_s._ 9_d._

_BEDDARD._--Works by FRANK E. BEDDARD, M.A. Oxon.

     ELEMENTARY PRACTICAL ZOOLOGY. With 93 Illustrations. Crown
     8vo., 2_s._ 6_d._

     THE STRUCTURE AND CLASSIFICATION OF BIRDS. With 252
     Illustrations. 8vo., 21_s._ net.

_BIDGOOD._--A COURSE OF PRACTICAL ELEMENTARY BIOLOGY. By JOHN BIDGOOD,
B.Sc, F.L.S. With 226 Illustrations. Crown 8vo., 4_s._ 6_d._

_BRAY._--PHYSIOLOGY AND THE LAWS OF HEALTH, in Easy Lessons for
Schools. By Mrs. CHARLES BRAY. Fcp. 8vo., 1_s._

_BRODIE._--THE ESSENTIALS OF EXPERIMENTAL PHYSIOLOGY. For the Use of
Students. By T. G. BRODIE, M.D., Lecturer on Physiology, St. Thomas's
Hospital Medical School. With 2 Plates and 177 Illustrations in the
Text. Crown 8vo., 6_s._ 6_d._

_FRANKLAND._--MICRO-ORGANISMS IN WATER. Together with an Account of
the Bacteriological Methods involved in their Investigation. Specially
designed for the use of those connected with the Sanitary Aspects of
Water-Supply. By PERCY FRANKLAND, Ph.D., B.Sc. (Lond.), F.R.S., and
Mrs. PERCY FRANKLAND. With 2 Plates and Numerous Diagrams. 8vo.,
16_s._ net.

_FURNEAUX._--HUMAN PHYSIOLOGY. By W. FURNEAUX, F.R.G.S. With 218
Illustrations. Crown 8vo., 2_s._ 6_d._

_HUDSON AND GOSSE._--THE ROTIFERA, or 'WHEEL-ANIMACULES'. By C. T.
HUDSON, LL.D., and P. H. GOSSE, F.R.S. With 30 Coloured and 4
Uncoloured Plates. In 6 Parts. 4to., 10_s._ 6_d._ each. Supplement
12_s._ 6_d._ Complete in 2 vols., with Supplement, 4to., £4 4_s._

_LEUMANN._--NOTES ON MICRO-ORGANISMS PATHOGENIC TO MAN. By
Surgeon-Captain B. H. S. LEUMANN, M.B., Indian Medical Service.
8vo., 3_s._

_MACALISTER._--Works by ALEXANDER MACALISTER, M.D.

     AN INTRODUCTION TO THE SYSTEMATIC ZOOLOGY AND MORPHOLOGY OF
     VERTEBRATE ANIMALS. With 41 Diagrams 8vo., 10_s._ 6_d._

     ZOOLOGY OF THE INVERTEBRATE ANIMALS. With 59 Diagrams. Fcp.
     8vo., 1_s._ 6_d._

     ZOOLOGY OF THE VERTEBRATE ANIMALS. With 77 Diagrams. Fcp.
     8vo., 1_s._ 6_d._

_MOORE._--ELEMENTARY PHYSIOLOGY. By BENJAMIN MOORE, M.A., Lecturer on
Physiology at the Charing Cross Hospital Medical School. With 125
Illustrations. Crown 8vo., 3_s._ 6_d._

_MORGAN._--ANIMAL BIOLOGY: an Elementary Text-Book. By C. LLOYD
MORGAN, F.R.S., Principal of University College, Bristol. With 103
Illustrations. Crown 8vo., 8_s._ 6_d._

_SCHENK._--MANUAL OF BACTERIOLOGY, for Practitioners and Students,
with Especial Reference to Practical Methods. By Dr. S. L. SCHENK.
With 100 Illustrations, some Coloured. 8vo., 10_s._ net.

_THORNTON._--HUMAN PHYSIOLOGY. By JOHN THORNTON, M.A. With 267
Illustrations, some Coloured. Crown 8vo., 6_s._




                         BOTANY AND GARDENING.


_AITKEN._--ELEMENTARY TEXT-BOOK OF BOTANY. By EDITH AITKEN, late
Scholar of Girton College. With 400 Diagrams. Crown 8vo., 4_s._ 6_d._

_BENNETT AND MURRAY._--HANDBOOK OF CRYPTOGAMIC BOTANY. By ALFRED W.
BENNETT, M.A., B.Sc., F.L.S., Lecturer on Botany at St. Thomas's
Hospital; and GEORGE MURRAY, F.L.S., Keeper of Botany, British Museum.
With 378 Illustrations. 8vo., 16_s._

_CROSS AND BEVAN._--CELLULOSE: an Outline of the Chemistry of the
Structural Elements of Plants. With Reference to their Natural History
and Industrial Uses. By CROSS and BEVAN (C. F. Cross, E. J. Bevan, and
C. Beadle). With 14 Plates. Crown 8vo., 12_s._ net.

_CURTIS._--A TEXT-BOOK OF GENERAL BOTANY. By CARLTON C. CURTIS, A.M.,
Ph.D., Tutor in Botany in Columbia University, U.S.A. With 87
Illustrations. 8vo., 12_s._ net.

_DE TABLEY._--THE FLORA OF CHESHIRE. By the late LORD DE TABLEY (Hon.
J. BYRNE LEICESTER WARREN, M.A.). Edited by SPENCER MOORE. With a
Biographical Notice of the Author by Sir MOUNTSTUART GRANT DUFF. With
a Map of Cheshire and a Photogravure Portrait. Crown 8vo., 10_s._
6_d._ net.

_EDMONDS._--Works by HENRY EDMONDS, B.Sc., London.

     ELEMENTARY BOTANY. With 342 Illustrations. Cr. 8vo., 2_s._
     6_d._

     BOTANY FOR BEGINNERS. With 85 Illustrations. Fcp. 8vo.,
     1_s._ 6_d._

_FARMER._--A PRACTICAL INTRODUCTION TO THE STUDY OF BOTANY: Flowering
Plants. By J. BRETLAND FARMER, F.R.S., M.A., Professor of Botany in
the Royal College of Science, London. With 121 Illustrations. Crown
8vo, 2_s._ 6_d._

_KITCHENER._--A YEAR'S BOTANY. Adapted to Home and School Use. By
FRANCES A. KITCHENER. With 195 Illustrations. Cr. 8vo., 5_s._

_LINDLEY AND MOORE._--THE TREASURY OF BOTANY. Edited by J. LINDLEY,
M.D., F.R.S., and T. MOORE, F.L.S. With 20 Steel Plates and numerous
Woodcuts. Two parts. Fcp. 8vo., 12_s._

_McNAB._--CLASS-BOOK OF BOTANY. By W. R. MCNAB.

     MORPHOLOGY AND PHYSIOLOGY. With 42 Diagrams. Fcp. 8vo.,
     1_s._ 6_d._

     CLASSIFICATION OF PLANTS. With 118 Diagrams. Fcp. 8vo.,
     1_s._ 6_d._

_SORAUER._--A POPULAR TREATISE ON THE PHYSIOLOGY OF PLANTS. By Dr.
PAUL SORAUER. Translated by F. E. WEISS, B.Sc., F.L.S. With 33
Illustrations. 8vo., 9_s._ net.

_THOMÉ AND BENNETT._--STRUCTURAL AND PHYSIOLOGICAL BOTANY. By OTTO
WILHELM THOMÉ and by ALFRED W. BENNETT, B.Sc., F.L.S. With Coloured
Map and 600 Woodcuts. Fcp. 8vo., 6_s._

_TUBEUF._--DISEASES OF PLANTS INDUCED BY CRYPTOGAMIC PARASITES.
Introduction to the Study of Pathogenic Fungi, Slime Fungi, Bacteria
and Algæ. By Dr. KARL FREIHERR VON TUBEUF, Privatdocent in the
University of Munich. English Edition by WILLIAM G. SMITH, B.Sc.,
Ph.D., Lecturer on Plant Physiology, University of Edinburgh. With 330
Illustrations. Royal 8vo., 18_s._ net.

_WATTS._--A SCHOOL FLORA. For the use of Elementary Botanical Classes.
By W. MARSHALL WATTS, D.Sc. Lond. Cr, 8vo., 2_s._ 6_d._

_WEATHERS._--A PRACTICAL GUIDE TO GARDEN PLANTS. Containing
Descriptions of the Hardiest and most Beautiful Annuals and Biennials,
Hardy Herbaceous and Bulbous Perennials, Hardy Water and Bog Plants,
Flowering and Ornamental Trees and Shrubs, Conifers, Hardy Ferns,
Hardy Bamboos and other Ornamental Grasses; and also the best kinds of
Fruit and Vegetables that may be grown in the Open Air in the British
Islands, with Full and Practical Instructions as to Culture and
Propagation. By JOHN WEATHERS, F.R.H.S., late Assistant Secretary to
the Royal Horticultural Society, formerly of the Royal Gardens, Kew,
etc. With 159 Diagrams. 8vo.




                             AGRICULTURE.


_ADDYMAN._--AGRICULTURAL ANALYSIS. A Manual of Quantitative Analysis
for Students of Agriculture. By FRANK T. ADDYMAN, B.Sc. (Lond.),
F.I.C. With 49 Illustrations. Crown 8vo., 5_s._ net.

_COLEMAN AND ADDYMAN._--PRACTICAL AGRICULTURAL CHEMISTRY. By J.
BERNARD COLEMAN, A.R.C.Sc., F.I.C., and FRANK T. ADDYMAN, B.Sc.
(Lond.), F.I.C. With 24 Illustrations. Crown 8vo., 1_s._ 6_d._ net.

_WEBB._--Works by HENRY J. WEBB, Ph.D., B.Sc. (Lond.).

     ELEMENTARY AGRICULTURE. A Text-Book specially adapted to the
     requirements of the Science and Art Department, the Junior
     Examination of the Royal Agricultural Society, and other
     Elementary Examinations. With 34 Illustrations. Crown 8vo.,
     2_s._ 6_d._

     AGRICULTURE. A Manual for Advanced Science Students. With
     100 Illustrations. Crown 8vo., 7_s._ 6_d._ net.




             WORKS BY JOHN TYNDALL, D.C.L., LL.D., F.R.S.


FRAGMENTS OF SCIENCE: a Series of Detached Essays, Addresses, and
Reviews. 2 vols. Crown 8vo., 16_s._

     Vol. I.--The Constitution of Nature--Radiation--On Radiant
     Heat in Relation to the Colour and Chemical Constitution of
     Bodies--New Chemical Reactions produced by Light--On Dust
     and Disease--Voyage to Algeria to observe the
     Eclipse--Niagara--The Parallel Roads of Glen Roy--Alpine
     Sculpture--Recent Experiments on Fog-Signals--On the Study
     of Physics--On Crystalline and Slaty Cleavage--On
     Paramagnetic and Diamagnetic Forces--Physical Basis of Solar
     Chemistry--Elementary Magnetism--On Force--Contributions to
     Molecular Physics--Life and Letters of FARADAY--The Copley
     Medallist of 1870--The Copley Medallist of 1871--Death by
     Lightning--Science and the Spirits.

     Vol. II.--Reflections on Prayer and Natural Law--Miracles
     and Special Providences--On Prayer as a Form of Physical
     Energy--Vitality--Matter and Force--Scientific
     Materialism--An Address to Students--Scientific Use of the
     Imagination--The Belfast Address--Apology for the Belfast
     Address--The Rev. JAMES MARTINEAU and the Belfast
     Address--Fermentation, and its Bearings on Surgery and
     Medicine--Spontaneous Generation--Science and Man--Professor
     Virchow and Evolution--The Electric Light.

NEW FRAGMENTS. Crown 8vo., 10_s._ 6_d._

    CONTENTS.--The Sabbath--Goethe's 'Farbenlehre'--Atoms,
    Molecules, and Ether Waves--Count Rumford--Louis Pasteur, his
    Life and Labours--The Rainbow and its Congeners--Address
    delivered at the Birkbeck Institution on October 22,
    1884--Thomas Young--Life in the Alps--About Common
    Water--Personal Recollections of Thomas Carlyle--On Unveiling
    the Statue of Thomas Carlyle--On the Origin, Propagation, and
    Prevention of Phthisis--Old Alpine Jottings--A Morning on Alp
    Lusgen.

LECTURES ON SOUND. With Frontispiece of Fog-Syren, and 203 other
Woodcuts and Diagrams in the Text. Crown 8vo., 10_s._ 6_d._

HEAT, A MODE OF MOTION. With 125 Woodcuts and Diagrams. Crown 8vo.,
12_s._

LECTURES ON LIGHT DELIVERED IN THE UNITED STATES IN 1872 AND 1873.
With Portrait, Lithographic Plate, and 59 Diagrams. Crown 8vo., 5_s._

ESSAYS ON THE FLOATING MATTER OF THE AIR IN RELATION TO PUTREFACTION
AND INFECTION. With 24 Woodcuts. Crown 8vo., 7_s._ 6_d._

RESEARCHES ON DIAMAGNETISM AND MAGNECRYSTALLIC ACTION; including the
Question of Diamagnetic Polarity. Crown 8vo., 12_s._

NOTES OF A COURSE OF NINE LECTURES ON LIGHT, delivered at the Royal
Institution of Great Britain, 1869. Crown 8vo., 1_s._ 6_d._

NOTES OF A COURSE OF SEVEN LECTURES ON ELECTRICAL PHENOMENA AND
THEORIES, delivered at the Royal Institution of Great Britain, 1870.
Crown 8vo., 1_s._ 6_d._

LESSONS IN ELECTRICITY AT THE ROYAL INSTITUTION 1875-1876. With 58
Woodcuts and Diagrams. Crown 8vo., 2_s._ 6_d._

THE GLACIERS OF THE ALPS: being a Narrative of Excursions and Ascents.
An Account of the Origin and Phenomena of Glaciers, and an Exposition
of the Physical Principles to which they are related. With 7
Illustrations. Crown 8vo., 6_s._ 6_d._ net.

HOURS OF EXERCISE IN THE ALPS. With 7 Illustrations. Crown 8vo., 6_s._
6_d._ net.

FARADAY AS A DISCOVERER. Crown 8vo., 3_s._ 6_d._




                        TEXT-BOOKS OF SCIENCE.


PHOTOGRAPHY. By Sir WILLIAM DE WIVELESLIE ABNEY, K.C.B., F.R.S. With
105 Illustrations. Fcp. 8vo., 3_s._ 6_d._

THE STRENGTH OF MATERIAL AND STRUCTURES. By Sir J. ANDERSON, C.E. With
66 Illustrations. Fcp. 8vo., 3_s._ 6_d._

RAILWAY APPLIANCES. By Sir JOHN WOLFE BARRY, K.C.B., F.R.S., M.I.C.E.
With 218 Illustrations. Fcp. 8vo., 4_s._ 6_d._

INTRODUCTION TO THE STUDY OF INORGANIC CHEMISTRY. By WILLIAM ALLEN
MILLER, M.D., LL.D., F.R.S. With 72 Illustrations. 3_s._ 6_d._

QUANTITATIVE CHEMICAL ANALYSIS. By T. E. THORPE, C.B., F.R.S., Ph.D.
With 88 Illustrations. Fcp. 8vo., 4_s._ 6_d._

QUALITATIVE ANALYSIS AND LABORATORY PRACTICE. By T. E. THORPE, C.B.,
Ph.D., F.R.S., and M. M. PATTISON MUIR, M.A. and F.R.S.E. With Plate
of Spectra and 57 Illustrations. Fcp. 8vo., 3_s._ 6_d._

INTRODUCTION TO THE STUDY OF CHEMICAL PHILOSOPHY. By WILLIAM A.
TILDEN, D.Sc., London, F.R.S. With 5 Illustrations. With or without
Answers to Problems. Fcp. 8vo., 4_s._ 6_d._

ELEMENTS OF ASTRONOMY. By Sir R. S. BALL, LL.D., F.R.S. With 130
Illustrations. Fcp. 8vo., 6_s._ 6_d._

SYSTEMATIC MINERALOGY. By HILARY BAUERMAN, F.G.S. With 373
Illustrations. Fcp. 8vo., 6_s._

DESCRIPTIVE MINERALOGY. By HILARY BAUERMAN, F.G.S., etc. With 236
Illustrations. Fcp. 8vo., 6_s._

METALS: THEIR PROPERTIES AND TREATMENT. By A. K. HUNTINGTON and W. G.
MCMILLAN. With 122 Illustrations. Fcp. 8vo., 7_s._ 6_d._

THEORY OF HEAT. By J. CLERK MAXWELL, M.A., LL.D., Edin., F.R.SS., L. &
E. With 38 Illustrations. Fcp. 8vo., 4_s._ 6_d._

PRACTICAL PHYSICS. By R. T. GLAZEBROOK, M.A., F.R.S., and W. N. SHAW,
M.A. With 134 Illustrations. Fcp. 8vo., 7_s._ 6_d._

PRELIMINARY SURVEY AND ESTIMATES. By THEODORE GRAHAM GRIBBLE, Civil
Engineer. Including Elementary Astronomy, Route Surveying,
Tacheometry, Curve-ranging, Graphic Mensuration, Estimates,
Hydrography and Instruments. With 133 Illustrations. Fcp. 8vo., 7_s._
6_d._

ALGEBRA AND TRIGONOMETRY. By WILLIAM NATHANIEL GRIFFIN, B.D. 3_s._
6_d._ Notes on, with Solutions of the more difficult Questions. Fcp.
8vo., 3_s._ 6_d._

THE STEAM ENGINE. By GEORGE C. V. HOLMES, Secretary of the Institution
of Naval Architects. With 212 Illustrations. Fcp. 8vo., 6_s._

ELECTRICITY AND MAGNETISM. By FLEEMING JENKIN, F.R.SS., L. & E. With
177 Illustrations. Fcp. 8vo., 3_s._ 6_d._

THE ART OF ELECTRO-METALLURGY. By G. GORE, LL.D., F.R.S. With 56
Illus. Fcp. 8vo., 6s.

TELEGRAPHY. By Sir W. H. PREECE, K.C.B., F.R.S., M.I.C.E., and Sir J.
SIVEWRIGHT, M.A., K.C.M.G. With 267 Illustrations. Fcp. 8vo., 6_s._

PHYSICAL OPTICS. By R. T. GLAZEBROOK, M.A., F.R.S. With 183
Illustrations. Fcp. 8vo., 6_s._

TECHNICAL ARITHMETIC AND MENSURATION. By CHARLES W. MERRIEFIELD,
F.R.S. 3_s._ 6_d._ Key, by the Rev. JOHN HUNTER, M.A. Fcp. 8vo., 3_s._
6_d._

THE STUDY OF ROCKS. By FRANK RUTLEY, F.G.S. With 6 Plates and 88
Illustrations Fcp. 8vo., 4_s._ 6_d._

WORKSHOP APPLIANCES, including Descriptions of some of the Machine
Tools used by Engineers. By C. P. B. SHELLEY, M.I.C.E. With 323
Illustrations. Fcp. 8vo., 5_s._

ELEMENTS OF MACHINE DESIGN. By W. CAWTHORNE UNWIN, F.R.S., B.Sc.,
M.I.C.E.

     Part I. General Principles, Fastenings and Transmissive
     Machinery. With 304 Illustrations. 6_s._

     Part II. Chiefly on Engine Details. With 174 Illustrations.
     Fcp. 8vo., 4_s._ 6_d._

STRUCTURAL AND PHYSIOLOGICAL BOTANY. By OTTO WILHELM THOMÉ, and A. W.
BENNETT, M.A., B.Sc., F.L.S. With 600 Illustrations. Fcp. 8vo., 6_s._

PLANE AND SOLID GEOMETRY. By H. W. WATSON, M.A. Fcp. 8vo. 3_s._ 6_d._




                      ADVANCED SCIENCE MANUALS.


BUILDING CONSTRUCTION. By the Author of 'Rivington's Notes on Building
Construction'. With 385 Illustrations and an Appendix of Examination
Questions. Crown 8vo., 4_s._ 6_d._

THEORETICAL MECHANICS. Solids, including Kinematics, Statics, and
Kinetics. By A. THORNTON, M.A., F.R.A.S. With 220 Illustrations, 130
Worked Examples, and over 900 Examples from Examination Papers, etc.
Crown 8vo., 4_s._ 6_d._

HEAT. By MARK R. WRIGHT, Hon. Inter. B.Sc. (Lond.). With 136
Illustrations and numerous Examples and Examination Papers. Crown
8vo., 4_s._ 6_d._

LIGHT. By W. J. A. EMTAGE, M.A. With 232 Illustrations. Cr. 8vo.,
6_s._

MAGNETISM AND ELECTRICITY. By ARTHUR WILLIAM POYSER, M.A. With 317
Illustrations. Crown 8vo., 4_s._ 6_d._

INORGANIC CHEMISTRY, THEORETICAL AND PRACTICAL. A Manual for Students
in Advanced Classes of the Science and Art Department. By WILLIAM
JAGO, F.C.S., F.I.C. With Plate of Spectra and 78 Woodcuts. Crown
8vo., 4s. 6d.

GEOLOGY: a Manual for Students in Advanced Classes and for General
Readers. By CHARLES BIRD, B.A. (Lond.), F.G.S. With over 300
Illustrations, a Geological Map of the British Isles (coloured), and a
set of Questions for Examination. Crown 8vo., 7_s._ 6_d._

HUMAN PHYSIOLOGY: a Manual for Students in advanced Classes of the
Science and Art Department. By JOHN THORNTON, M.A. With 268
Illustrations, some of which are Coloured, and a set of Questions for
Examination. Crown 8vo., 6_s._

PHYSIOGRAPHY. By JOHN THORNTON, M.A. With 6 Maps, 203 Illustrations,
and Coloured Plate of Spectra. Crown 8vo., 4_s._ 6_d._

AGRICULTURE. By HENRY J. WEBB, Ph.D., B.Sc. With 100 Illustrations.
Crown 8vo., 7_s._ 6_d._ net.

HYGIENE. By J. LANE NOTTER, M.A., M.D., Professor of Hygiene in the
Army Medical School, Netley, Colonel, Royal Army Medical Corps; and R.
H. FIRTH, F.R.C.S., late Assistant Professor of Hygiene in the Army
Medical School, Netley, Major, Royal Army Medical Corps. With 95
Illustrations. Crown 8vo., 3_s._ 6_d._




                     ELEMENTARY SCIENCE MANUALS.

    *** _Written specially to meet the requirements of the
    ELEMENTARY STAGE OF SCIENCE SUBJECTS as laid down in the
    Syllabus of the Directory of the SCIENCE AND ART DEPARTMENT._

PRACTICAL, PLANE, AND SOLID GEOMETRY, including Graphic Arithmetic. By
I. H. MORRIS. Fully Illustrated with Drawings. Crown 8vo., 2_s._ 6_d._

GEOMETRICAL DRAWING FOR ART STUDENTS. Embracing Plane Geometry and its
Applications, the Use of Scales, and the Plans and Elevations of
Solids, as required for the Examinations of the Science and Art
Department. By I. H. MORRIS. Crown 8vo., 1_s._ 6_d._

TEXT-BOOK ON PRACTICAL, SOLID, OR DESCRIPTIVE GEOMETRY. By DAVID ALLAN
LOW (Whitworth Scholar). Part I. Crown 8vo., 2_s._ Part II. Crown
8vo., 3_s._

AN INTRODUCTION TO MACHINE DRAWING AND DESIGN. By DAVID ALLAN LOW.
With 153 Illustrations. Crown 8vo., 2_s._ 6_d._

BUILDING CONSTRUCTION AND DRAWING. By EDWARD J. BURRELL. With 308
Illustrations and Working Drawings. Crown 8vo., 2_s._ 6_d._

AN ELEMENTARY COURSE OF MATHEMATICS. Containing Arithmetic; Euclid
(Book I., with Deductions and Exercises); and Algebra. Crown 8vo.,
2_s._ 6_d._

THEORETICAL MECHANICS. Including Hydrostatics and Pneumatics. By J. E.
TAYLOR, M.A., B.Sc. With numerous Examples and Answers, and 175
Diagrams and Illustrations. Crown 8vo., 2_s._ 6_d._

THEORETICAL MECHANICS--SOLIDS. By J. E. TAYLOR, M.A., B.Sc. (Lond.).
With 163 Illustrations, 120 Worked Examples, and over 500 Examples
from Examination Papers, etc. Crown 8vo., 2_s._ 6_d._

THEORETICAL MECHANICS--FLUIDS. By J. E. TAYLOR, M.A., B.Sc. (Lond.).
With 122 Illustrations, numerous Worked Examples, and about 500
Examples from Examination Papers, etc. Crown 8vo., 2_s._ 6_d._

A MANUAL OF MECHANICS. With 138 Illustrations and Diagrams, and 188
Examples taken from Examination Papers, with Answers. By T. M.
GOODEVE, M.A. Crown 8vo., 2_s._ 6_d._

SOUND, LIGHT, AND HEAT. By MARK R. WRIGHT, M.A. With 160 Diagrams and
Illustrations. Crown 8vo., 2_s._ 6_d._

METALLURGY: an Elementary Text-Book. By E. L. RHEAD. With 94
Illustrations. Crown 8vo., 3_s._ 6_d._

PHYSICS. Alternative Course. By MARK R. WRIGHT, M.A. With 242
Illustrations. Crown 8vo., 2_s._ 6_d._

MAGNETISM AND ELECTRICITY. By A. W. POYSER, M.A. With 235
Illustrations. Crown 8vo., 2_s._ 6_d._

ORGANIC CHEMISTRY: the Fatty Compounds. By R. LLOYD WHITELEY, F.I.C.,
F.C.S. With 45 Illustrations. Crown 8vo., 3_s._ 6_d._

INORGANIC CHEMISTRY, THEORETICAL AND PRACTICAL. By WILLIAM JAGO,
F.C.S., F.I.C. With 63 Illustrations and numerous Questions and
Exercises. Fcp. 8vo., 2_s._ 6_d._

AN INTRODUCTION TO PRACTICAL INORGANIC CHEMISTRY. By WILLIAM JAGO,
F.C.S., F.I.C. Crown 8vo., 1_s._ 6_d._

PRACTICAL CHEMISTRY: the Principles of Qualitative Analysis. By
WILLIAM A. TILDEN, D.Sc. Fcp. 8vo., 1_s._ 6_d._

ELEMENTARY INORGANIC CHEMISTRY. By WILLIAM FURNEAUX, F.R.G.S. Crown
8vo., 2_s._ 6_d._

ELEMENTARY GEOLOGY. By CHARLES BIRD, B.A., F.G.S. With Coloured
Geological Map of the British Islands, and 247 Illustrations. Crown
8vo., 2_s._ 6_d._

HUMAN PHYSIOLOGY. By WILLIAM FURNEAUX, F.R.G.S. With 218
Illustrations. Crown 8vo., 2_s._ 6_d._

A COURSE OF PRACTICAL ELEMENTARY BIOLOGY. By J. BIDGOOD, B.Sc. With
226 Illustrations. Crown 8vo., 4_s._ 6_d._

ELEMENTARY BOTANY, THEORETICAL AND PRACTICAL. By HENRY EDMONDS, B.Sc.
With 342 Illustrations. Crown 8vo., 2_s._ 6_d._

STEAM. By WILLIAM RIPPER, Member of the Institution of Mechanical
Engineers. With 142 Illustrations. Crown 8vo., 2_s._ 6_d._

ELEMENTARY PHYSIOGRAPHY. By J. THORNTON, M.A. With 13 Maps and 295
Illustrations. With Appendix on Astronomical Instruments and
Measurements. Crown 8vo., 2_s._ 6_d._

AGRICULTURE. By HENRY J. WEBB, Ph.D. With 34 Illustrations. Crown
8vo., 2_s._ 6_d._




                    THE LONDON SCIENCE CLASS-BOOKS.


Edited by G. CAREY FOSTER, F.R.S., and by Sir PHILIP MAGNUS, B.Sc.,
B.A., of the City and Guilds of London Institute.

ASTRONOMY. By Sir ROBERT STAWELL BALL, LL.D., F.R.S. With 41 Diagrams.
Fcp. 8vo., 1_s._ 6_d._

MECHANICS. By Sir ROBERT STAWELL BALL, LL.D., F.R.S. With 89 Diagrams.
Fcp. 8vo., 1_s._ 6_d._

THE LAWS OF HEALTH. By W. H. CORFIELD, M.A., M.D., F.R.C.P. With 22
Illustrations. Fcp. 8vo., 1_s._ 6_d._

MOLECULAR PHYSICS AND SOUND. By FREDERICK GUTHRIE, F.R.S. With 91
Diagrams. Fcp. 8vo., 1_s._ 6_d._

GEOMETRY, CONGRUENT FIGURES. By O. HENRICI, Ph.D., F.R.S. With 141
Diagrams. Fcp. 8vo., 1_s._ 6_d._

ZOOLOGY OF THE INVERTEBRATE ANIMALS. BY ALEXANDER MACALISTER, M.D.
With 59 Diagrams. Fcp. 8vo., 1_s._ 6_d._

ZOOLOGY OF THE VERTEBRATE ANIMALS. By ALEXANDER MACALISTER, M.D. With
77 Diagrams. Fcp. 8vo., 1_s._ 6_d._

HYDROSTATICS AND PNEUMATICS. By Sir PHILIP MAGNUS, B.Sc., B.A. With 79
Diagrams. Fcp. 8vo., 1_s._ 6_d._ (To be had also _with Answers_,
2_s._) The Worked Solutions of the Problems, 2_s._

BOTANY. Outlines of the Classification of Plants. By W. R. MCNAB, M.D.
With 118 Diagrams. Fcp. 8vo., 1_s._ 6_d._

BOTANY. Outlines of Morphology and Physiology. By W. R. MCNAB, M.D.
With 42 Diagrams. Fcp. 8vo., 1_s._ 6_d._

THERMODYNAMICS. By RICHARD WORMELL, M.A., D.Sc. With 41 Diagrams. Fcp.
8vo., 1_s._ 6_d._




                 PRACTICAL ELEMENTARY SCIENCE SERIES.


ELEMENTARY PRACTICAL PHYSIOGRAPHY. (Section I.) By JOHN THORNTON,
M.A., Head Master of the Central Higher Grade School, Bolton. With 215
Illustrations and a Coloured Spectrum. Crown 8vo., 2_s._ 6_d._

ELEMENTARY PRACTICAL PHYSIOGRAPHY. (Section II.). A Course of Lessons
and Experiments in Elementary Science for the Queen's Scholarship
Examination. By JOHN THORNTON, M.A. With 98 Illustrations and a Series
of Questions. Crown 8vo., 2_s._ 6_d._

PRACTICAL DOMESTIC HYGIENE. By J. LANE NOTTER, M.A., M.D., Professor
of Hygiene in the Army Medical School, Netley, etc.; and R. H. FIRTH,
F.R.C.S., late Assistant Professor of Hygiene in the Army Medical
School, Netley, etc. With 83 Illustrations. Crown 8vo., 2_s._ 6_d._

PRACTICAL MATHEMATICS. By A. G. CRACKNELL, M.A., B.Sc. Crown 8vo.,
3_s._ 6_d._

A PRACTICAL INTRODUCTION TO THE STUDY OF BOTANY: Flowering Plants. By
J. BRETLAND FARMER, F.R.S., M.A., Professor of Botany in the Royal
College of Science, London. With 121 Illustrations. Crown 8vo., 2_s._
6_d._

ELEMENTARY PRACTICAL CHEMISTRY. By G. S. NEWTH, F.I.C., F.C.S.,
Demonstrator in the Royal College of Science, London, etc. With 108
Illustrations and 254 Experiments. Crown 8vo., 2_s._ 6_d._

ELEMENTARY PRACTICAL PHYSICS. By W. WATSON, B.Sc., Assistant Professor
of Physics in the Royal College of Science, London, etc. With 120
Illustrations and 193 Exercises. Crown 8vo., 2_s._ 6_d._

ELEMENTARY PRACTICAL ZOOLOGY. By FRANK E. BEDDARD, M.A. Oxon., F.R.S.,
Prosector to the Zoological Society of London. With 93 Illustrations.
Crown 8vo., 2_s._ 6_d._


                    _OTHER VOLUMES IN PREPARATION._




                          TRANSCRIBER'S NOTES


1. Passages in italics are surrounded by _underscores_.

2. The word Pharmacopoeia uses an oe ligature in the original.

3. Minor changes were made for the purpose of consistency in the book
list at the end, like adding period, etc.

4. The following misprints have been corrected:
     "sufficiemt" corrected to "sufficient" (page 45)
     Changed "--" to "-" in nitrogen-fixing (page 151)
     Joined words "intel lectual" split over two lines (page 236)
     Missing text "to" added after "incidental" (page 285)

5. Other than the corrections listed above, printer's inconsistencies
in spelling, punctuation and hyphenation have been retained.





End of Project Gutenberg's Twentieth Century Inventions, by George Sutherland

*** END OF THIS PROJECT GUTENBERG EBOOK TWENTIETH CENTURY INVENTIONS ***

***** This file should be named 31243-8.txt or 31243-8.zip *****
This and all associated files of various formats will be found in:
        http://www.gutenberg.org/3/1/2/4/31243/

Produced by Chris Curnow and the Online Distributed
Proofreading Team at http://www.pgdp.net (This file was
produced from images generously made available by The
Internet Archive)


Updated editions will replace the previous one--the old editions
will be renamed.

Creating the works from public domain print editions means that no
one owns a United States copyright in these works, so the Foundation
(and you!) can copy and distribute it in the United States without
permission and without paying copyright royalties.  Special rules,
set forth in the General Terms of Use part of this license, apply to
copying and distributing Project Gutenberg-tm electronic works to
protect the PROJECT GUTENBERG-tm concept and trademark.  Project
Gutenberg is a registered trademark, and may not be used if you
charge for the eBooks, unless you receive specific permission.  If you
do not charge anything for copies of this eBook, complying with the
rules is very easy.  You may use this eBook for nearly any purpose
such as creation of derivative works, reports, performances and
research.  They may be modified and printed and given away--you may do
practically ANYTHING with public domain eBooks.  Redistribution is
subject to the trademark license, especially commercial
redistribution.



*** START: FULL LICENSE ***

THE FULL PROJECT GUTENBERG LICENSE
PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK

To protect the Project Gutenberg-tm mission of promoting the free
distribution of electronic works, by using or distributing this work
(or any other work associated in any way with the phrase "Project
Gutenberg"), you agree to comply with all the terms of the Full Project
Gutenberg-tm License (available with this file or online at
http://gutenberg.net/license).


Section 1.  General Terms of Use and Redistributing Project Gutenberg-tm
electronic works

1.A.  By reading or using any part of this Project Gutenberg-tm
electronic work, you indicate that you have read, understand, agree to
and accept all the terms of this license and intellectual property
(trademark/copyright) agreement.  If you do not agree to abide by all
the terms of this agreement, you must cease using and return or destroy
all copies of Project Gutenberg-tm electronic works in your possession.
If you paid a fee for obtaining a copy of or access to a Project
Gutenberg-tm electronic work and you do not agree to be bound by the
terms of this agreement, you may obtain a refund from the person or
entity to whom you paid the fee as set forth in paragraph 1.E.8.

1.B.  "Project Gutenberg" is a registered trademark.  It may only be
used on or associated in any way with an electronic work by people who
agree to be bound by the terms of this agreement.  There are a few
things that you can do with most Project Gutenberg-tm electronic works
even without complying with the full terms of this agreement.  See
paragraph 1.C below.  There are a lot of things you can do with Project
Gutenberg-tm electronic works if you follow the terms of this agreement
and help preserve free future access to Project Gutenberg-tm electronic
works.  See paragraph 1.E below.

1.C.  The Project Gutenberg Literary Archive Foundation ("the Foundation"
or PGLAF), owns a compilation copyright in the collection of Project
Gutenberg-tm electronic works.  Nearly all the individual works in the
collection are in the public domain in the United States.  If an
individual work is in the public domain in the United States and you are
located in the United States, we do not claim a right to prevent you from
copying, distributing, performing, displaying or creating derivative
works based on the work as long as all references to Project Gutenberg
are removed.  Of course, we hope that you will support the Project
Gutenberg-tm mission of promoting free access to electronic works by
freely sharing Project Gutenberg-tm works in compliance with the terms of
this agreement for keeping the Project Gutenberg-tm name associated with
the work.  You can easily comply with the terms of this agreement by
keeping this work in the same format with its attached full Project
Gutenberg-tm License when you share it without charge with others.

1.D.  The copyright laws of the place where you are located also govern
what you can do with this work.  Copyright laws in most countries are in
a constant state of change.  If you are outside the United States, check
the laws of your country in addition to the terms of this agreement
before downloading, copying, displaying, performing, distributing or
creating derivative works based on this work or any other Project
Gutenberg-tm work.  The Foundation makes no representations concerning
the copyright status of any work in any country outside the United
States.

1.E.  Unless you have removed all references to Project Gutenberg:

1.E.1.  The following sentence, with active links to, or other immediate
access to, the full Project Gutenberg-tm License must appear prominently
whenever any copy of a Project Gutenberg-tm work (any work on which the
phrase "Project Gutenberg" appears, or with which the phrase "Project
Gutenberg" is associated) is accessed, displayed, performed, viewed,
copied or distributed:

This eBook is for the use of anyone anywhere at no cost and with
almost no restrictions whatsoever.  You may copy it, give it away or
re-use it under the terms of the Project Gutenberg License included
with this eBook or online at www.gutenberg.net

1.E.2.  If an individual Project Gutenberg-tm electronic work is derived
from the public domain (does not contain a notice indicating that it is
posted with permission of the copyright holder), the work can be copied
and distributed to anyone in the United States without paying any fees
or charges.  If you are redistributing or providing access to a work
with the phrase "Project Gutenberg" associated with or appearing on the
work, you must comply either with the requirements of paragraphs 1.E.1
through 1.E.7 or obtain permission for the use of the work and the
Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or
1.E.9.

1.E.3.  If an individual Project Gutenberg-tm electronic work is posted
with the permission of the copyright holder, your use and distribution
must comply with both paragraphs 1.E.1 through 1.E.7 and any additional
terms imposed by the copyright holder.  Additional terms will be linked
to the Project Gutenberg-tm License for all works posted with the
permission of the copyright holder found at the beginning of this work.

1.E.4.  Do not unlink or detach or remove the full Project Gutenberg-tm
License terms from this work, or any files containing a part of this
work or any other work associated with Project Gutenberg-tm.

1.E.5.  Do not copy, display, perform, distribute or redistribute this
electronic work, or any part of this electronic work, without
prominently displaying the sentence set forth in paragraph 1.E.1 with
active links or immediate access to the full terms of the Project
Gutenberg-tm License.

1.E.6.  You may convert to and distribute this work in any binary,
compressed, marked up, nonproprietary or proprietary form, including any
word processing or hypertext form.  However, if you provide access to or
distribute copies of a Project Gutenberg-tm work in a format other than
"Plain Vanilla ASCII" or other format used in the official version
posted on the official Project Gutenberg-tm web site (www.gutenberg.net),
you must, at no additional cost, fee or expense to the user, provide a
copy, a means of exporting a copy, or a means of obtaining a copy upon
request, of the work in its original "Plain Vanilla ASCII" or other
form.  Any alternate format must include the full Project Gutenberg-tm
License as specified in paragraph 1.E.1.

1.E.7.  Do not charge a fee for access to, viewing, displaying,
performing, copying or distributing any Project Gutenberg-tm works
unless you comply with paragraph 1.E.8 or 1.E.9.

1.E.8.  You may charge a reasonable fee for copies of or providing
access to or distributing Project Gutenberg-tm electronic works provided
that

- You pay a royalty fee of 20% of the gross profits you derive from
     the use of Project Gutenberg-tm works calculated using the method
     you already use to calculate your applicable taxes.  The fee is
     owed to the owner of the Project Gutenberg-tm trademark, but he
     has agreed to donate royalties under this paragraph to the
     Project Gutenberg Literary Archive Foundation.  Royalty payments
     must be paid within 60 days following each date on which you
     prepare (or are legally required to prepare) your periodic tax
     returns.  Royalty payments should be clearly marked as such and
     sent to the Project Gutenberg Literary Archive Foundation at the
     address specified in Section 4, "Information about donations to
     the Project Gutenberg Literary Archive Foundation."

- You provide a full refund of any money paid by a user who notifies
     you in writing (or by e-mail) within 30 days of receipt that s/he
     does not agree to the terms of the full Project Gutenberg-tm
     License.  You must require such a user to return or
     destroy all copies of the works possessed in a physical medium
     and discontinue all use of and all access to other copies of
     Project Gutenberg-tm works.

- You provide, in accordance with paragraph 1.F.3, a full refund of any
     money paid for a work or a replacement copy, if a defect in the
     electronic work is discovered and reported to you within 90 days
     of receipt of the work.

- You comply with all other terms of this agreement for free
     distribution of Project Gutenberg-tm works.

1.E.9.  If you wish to charge a fee or distribute a Project Gutenberg-tm
electronic work or group of works on different terms than are set
forth in this agreement, you must obtain permission in writing from
both the Project Gutenberg Literary Archive Foundation and Michael
Hart, the owner of the Project Gutenberg-tm trademark.  Contact the
Foundation as set forth in Section 3 below.

1.F.

1.F.1.  Project Gutenberg volunteers and employees expend considerable
effort to identify, do copyright research on, transcribe and proofread
public domain works in creating the Project Gutenberg-tm
collection.  Despite these efforts, Project Gutenberg-tm electronic
works, and the medium on which they may be stored, may contain
"Defects," such as, but not limited to, incomplete, inaccurate or
corrupt data, transcription errors, a copyright or other intellectual
property infringement, a defective or damaged disk or other medium, a
computer virus, or computer codes that damage or cannot be read by
your equipment.

1.F.2.  LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right
of Replacement or Refund" described in paragraph 1.F.3, the Project
Gutenberg Literary Archive Foundation, the owner of the Project
Gutenberg-tm trademark, and any other party distributing a Project
Gutenberg-tm electronic work under this agreement, disclaim all
liability to you for damages, costs and expenses, including legal
fees.  YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT
LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE
PROVIDED IN PARAGRAPH F3.  YOU AGREE THAT THE FOUNDATION, THE
TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE
LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR
INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH
DAMAGE.

1.F.3.  LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a
defect in this electronic work within 90 days of receiving it, you can
receive a refund of the money (if any) you paid for it by sending a
written explanation to the person you received the work from.  If you
received the work on a physical medium, you must return the medium with
your written explanation.  The person or entity that provided you with
the defective work may elect to provide a replacement copy in lieu of a
refund.  If you received the work electronically, the person or entity
providing it to you may choose to give you a second opportunity to
receive the work electronically in lieu of a refund.  If the second copy
is also defective, you may demand a refund in writing without further
opportunities to fix the problem.

1.F.4.  Except for the limited right of replacement or refund set forth
in paragraph 1.F.3, this work is provided to you 'AS-IS' WITH NO OTHER
WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
WARRANTIES OF MERCHANTIBILITY OR FITNESS FOR ANY PURPOSE.

1.F.5.  Some states do not allow disclaimers of certain implied
warranties or the exclusion or limitation of certain types of damages.
If any disclaimer or limitation set forth in this agreement violates the
law of the state applicable to this agreement, the agreement shall be
interpreted to make the maximum disclaimer or limitation permitted by
the applicable state law.  The invalidity or unenforceability of any
provision of this agreement shall not void the remaining provisions.

1.F.6.  INDEMNITY - You agree to indemnify and hold the Foundation, the
trademark owner, any agent or employee of the Foundation, anyone
providing copies of Project Gutenberg-tm electronic works in accordance
with this agreement, and any volunteers associated with the production,
promotion and distribution of Project Gutenberg-tm electronic works,
harmless from all liability, costs and expenses, including legal fees,
that arise directly or indirectly from any of the following which you do
or cause to occur: (a) distribution of this or any Project Gutenberg-tm
work, (b) alteration, modification, or additions or deletions to any
Project Gutenberg-tm work, and (c) any Defect you cause.


Section  2.  Information about the Mission of Project Gutenberg-tm

Project Gutenberg-tm is synonymous with the free distribution of
electronic works in formats readable by the widest variety of computers
including obsolete, old, middle-aged and new computers.  It exists
because of the efforts of hundreds of volunteers and donations from
people in all walks of life.

Volunteers and financial support to provide volunteers with the
assistance they need are critical to reaching Project Gutenberg-tm's
goals and ensuring that the Project Gutenberg-tm collection will
remain freely available for generations to come.  In 2001, the Project
Gutenberg Literary Archive Foundation was created to provide a secure
and permanent future for Project Gutenberg-tm and future generations.
To learn more about the Project Gutenberg Literary Archive Foundation
and how your efforts and donations can help, see Sections 3 and 4
and the Foundation web page at http://www.pglaf.org.


Section 3.  Information about the Project Gutenberg Literary Archive
Foundation

The Project Gutenberg Literary Archive Foundation is a non profit
501(c)(3) educational corporation organized under the laws of the
state of Mississippi and granted tax exempt status by the Internal
Revenue Service.  The Foundation's EIN or federal tax identification
number is 64-6221541.  Its 501(c)(3) letter is posted at
http://pglaf.org/fundraising.  Contributions to the Project Gutenberg
Literary Archive Foundation are tax deductible to the full extent
permitted by U.S. federal laws and your state's laws.

The Foundation's principal office is located at 4557 Melan Dr. S.
Fairbanks, AK, 99712., but its volunteers and employees are scattered
throughout numerous locations.  Its business office is located at
809 North 1500 West, Salt Lake City, UT 84116, (801) 596-1887, email
business@pglaf.org.  Email contact links and up to date contact
information can be found at the Foundation's web site and official
page at http://pglaf.org

For additional contact information:
     Dr. Gregory B. Newby
     Chief Executive and Director
     gbnewby@pglaf.org


Section 4.  Information about Donations to the Project Gutenberg
Literary Archive Foundation

Project Gutenberg-tm depends upon and cannot survive without wide
spread public support and donations to carry out its mission of
increasing the number of public domain and licensed works that can be
freely distributed in machine readable form accessible by the widest
array of equipment including outdated equipment.  Many small donations
($1 to $5,000) are particularly important to maintaining tax exempt
status with the IRS.

The Foundation is committed to complying with the laws regulating
charities and charitable donations in all 50 states of the United
States.  Compliance requirements are not uniform and it takes a
considerable effort, much paperwork and many fees to meet and keep up
with these requirements.  We do not solicit donations in locations
where we have not received written confirmation of compliance.  To
SEND DONATIONS or determine the status of compliance for any
particular state visit http://pglaf.org

While we cannot and do not solicit contributions from states where we
have not met the solicitation requirements, we know of no prohibition
against accepting unsolicited donations from donors in such states who
approach us with offers to donate.

International donations are gratefully accepted, but we cannot make
any statements concerning tax treatment of donations received from
outside the United States.  U.S. laws alone swamp our small staff.

Please check the Project Gutenberg Web pages for current donation
methods and addresses.  Donations are accepted in a number of other
ways including including checks, online payments and credit card
donations.  To donate, please visit: http://pglaf.org/donate


Section 5.  General Information About Project Gutenberg-tm electronic
works.

Professor Michael S. Hart is the originator of the Project Gutenberg-tm
concept of a library of electronic works that could be freely shared
with anyone.  For thirty years, he produced and distributed Project
Gutenberg-tm eBooks with only a loose network of volunteer support.


Project Gutenberg-tm eBooks are often created from several printed
editions, all of which are confirmed as Public Domain in the U.S.
unless a copyright notice is included.  Thus, we do not necessarily
keep eBooks in compliance with any particular paper edition.


Most people start at our Web site which has the main PG search facility:

     http://www.gutenberg.net

This Web site includes information about Project Gutenberg-tm,
including how to make donations to the Project Gutenberg Literary
Archive Foundation, how to help produce our new eBooks, and how to
subscribe to our email newsletter to hear about new eBooks.