Project Gutenberg's Scientific American Supplement, No. 303, by Various

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Title: Scientific American Supplement, No. 303
       October 22, 1881

Author: Various

Posting Date: October 10, 2012 [EBook #8296]
Release Date: June, 2005
First Posted: July 4, 2003

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SCIENTIFIC AMERICAN SUPPLEMENT NO. 303




NEW YORK, OCTOBER 22, 1881

Scientific American Supplement. Vol. XII, No. 303.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.


       *       *       *       *       *

     TABLE OF CONTENTS

I.   ENGINEERING AND MECHANICS.--New Eighty-ton Steam Hammer at the Saint
     Chamond Works, France.--7 figures.--Elevation of hammer.--Profile--
     Transverse section.--Profile view of foundation, etc.--Plan of
     plant.--General plan of the forging mill.--Details of truss and
     support for the cranes.

     Great Steamers.--Comparative details of the Servia, the City of Rome,
     the Alaska, and the Great Eastern.

     Improved Road Locomotive.--2 figures.--Side and end views

     American Milling Methods. By ALBERT HOPPIN.--Ten years' progress.--Low
     milling.--Half high milling.--High milling.--Important paper read
     before the Pennsylvania State Millers' Association.

     Machine for Dotting Tulles and other Light Fabrics.--3 figures.

II.  TECHNOLOGY AND CHEMISTRY.--The Reproduction and Multiplication of
     Negatives. By ERNEST EDWARDS.

     A New Method of Making Gelatine Emulsion. By W. K. BURTON.

     The Pottery and Porcelain Industries of Japan.

     Crystallization Table.

     The Principles of Hop Analysis. By Dr. G. O. CECH.

     Water Gas.--A description of apparatus for producing cheap gas, and
     some notes on the economical effects of using such gas with gas
     motors, etc.--By J. EMERSON DOWSON.

     On the Fluid Density of Certain Metals. By Professors CHANDLER ROBERTS
     and T. WRIGLESON.

III. PHYSICS, ELECTRICITY, ETC.--Electric Power.--The nature and uses of
     electricity.--Electricity vs. steam.

     On the Method of Obtaining and Measuring Very High Vacua with a
     Modified Form of Sprengel Pump. By Prof OGDEN N. ROOD.--4 figures.--
     Apparatus for obtaining vacua of one four hundred-millionth of an
     atmosphere--Construction.--Manipulation.--Calculations.--Results

IV.  ART, ARCHITECTURE, ETC.--Old Wrought Iron Gates, Guildhall.
     Worcester, England. 1 figure.

     The French Crystal Palace, Park of St. Cloud, Paris. 1 full page
     illustration.

     Suggestions in Architecture. A Castellated Chateau. Perspective and
     plan. Chateau in the AEgean Sea.

V.   HYGIENE AND MEDICINE.--Hydrophobia Prevented by Vaccination.

     On Diptera as Spreaders of Disease. By J. W. SLATER.

     On the Relations of Minute Organisms to Certain Specific Diseases.

VI.  ASTRONOMY--The Centenary of the Discovery of Uranus. By F. W. DENNING.
     2 figures. Approximate place of Uranus among the stars at its
     discovery, March l3, 1871.--Orbits of the Uranian Satellites.

VII. BIOLOGY, ETC.--The Varying Susceptibility of Plants and Animals to
     Poisons and Disease.

     Kind Treatment of Horses.

       *       *       *       *       *




NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS


Ever since the improvements that have been introduced into the
manufacture of steel, and especially into the erection of works for its
production, have made it possible to obtain this metal in very large
masses, it has necessarily been preferred to iron for all pieces of
large dimensions, inasmuch as it possesses in the highest degree that
homogeneousness and resistance which are so difficult to obtain in the
latter metal. It has consequently been found necessary to construct
engines sufficiently powerful to effect the forging of enormous
ingots, as well as special furnaces for heating them and apparatus for
manipulating and transporting them.

The greatest efforts in this direction have been made with a view to
supplying the wants of heavy artillery and of naval constructions;
and to these efforts is metallurgy indebted for the creation of
establishments on a scale that no one would have dared a few years ago
to think of. The forging mill which we are about to describe is one of
those creations which is destined to remain for a long time yet very
rare; and one which is fully able to respond, not only to all present
exigencies, but also, as far as can be foreseen, to all those that may
arise for a long period to come. The mill is constructed as a portion of
the vast works that the Compagnie des Forges et Acieries de la Marine
own at Saint Chamond, and which embrace likewise a powerful steel works
that furnishes, especially, large ingots exceeding 100 tons in weight.

The mill consists, altogether, of three hammers, located in the same
room, and being of unequal powers in order to respond to different
requirements. The largest of these hammers is of 80 tons weight, and
the other two weigh respectively 35 and 28 tons. Each of them has
a corresponding furnace for heating by gas, as well as cranes for
maneuvering the ingots and the different engines. The general plan view
in Fig. 4 shows the arrangement of the hammers, cranes, and furnaces in
the millhouse.

[Illustration: FIG. A.--ELEVATION OF A HAMMER. FIG. B.--PROFILE VIEW]

The gas generators which supply the gas-furnaces are located out of
doors, as are the steam-generators. The ingots are brought from the
steel factory, and the forged pieces are taken away, by special trucks
running on a system of rails. We shall now give the most important
details in regard to the different parts of the works.

_The Mill-House_--This consists of a central room, 262 feet long, 98
feet wide, and 68 feet in height, with two lean-to annexes of 16 feet
each, making the total width 100 feet. The structure is wholly of metal,
and is so arranged as to permit of advantage being taken of every foot
of space under cover. For this purpose the system of construction
without tie-beams, known as the "De Dion type," has been adopted. Fig.
1 gives a general view of one of the trusses, and Fig. 5 shows some
further details. The binding-rafters consist of four angle-irons
connected by cross-bars of flat iron. The covering of corrugated
galvanized iron rests directly upon the binding-rafters, the upper parts
of which are covered with wood for the attachment of the corrugated
metal. The spacing of these rafters is calculated according to the
length of the sheets of corrugated iron, thus dispensing with the use of
ordinary rafters, and making a roof which is at once very light and very
durable, and consequently very economical. Rain falling on the roof
flows into leaden gutters, from whence it is carried by leaders into a
subterranean drain. The vertical walls of the structure are likewise of
corrugated iron, and the general aspect of the building is very original
and very satisfactory.

_The 80 Ton Hammer_--The three hammers, notwithstanding their difference
in power, present similar arrangements, and scarcely vary except in
dimensions. We shall confine ourselves here to a description of the 80
ton apparatus. This consists, in addition to the hammer, properly so
called, of three cranes of 120 tons each, serving to maneuver the pieces
to be forged, and of a fourth of 75 tons for maneuvering the working
implements. These four cranes are arranged symmetrically around the
hammer, and are supported at their upper extremity by metallic stays.
Besides the foregoing there are three gas furnaces for heating the
ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus.

_Foundations of the Hammer and Composition of the Anvil-Bed_--To obtain
a foundation for the hammer an excavation was made to a depth of 26 feet
until a bed of solid rock was reached, and upon this there was then
spread a thick layer of beton, and upon this again there was placed a
bed of dressed stones in the part that was to receive the anvil-stock
and hammer.

On this base of dressed stones there was placed a bed formed of logs
of heartwood of oak squaring 16 inches by 3 feet in height, standing
upright, joined together very perfectly, and kept in close juxtaposition
by a double band of iron straps joined by bolts. The object of this
wooden bed was to deaden, in a great measure, the effect of the shock
transmitted by the anvil-stock.

NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS.

[Illustration: FIG. 1.--TRANSVERSE SECTION.]

[Illustration: FIG. 2.--PLAN.]

[Illustration: FIG. 3.--PROFILE VIEW.]

[Illustration: FIG. 4.--GENERAL PLAN OF THE FORGING MILL.]

[Illustration: FIG. 5.--DETAILS OF THE TRUSSAND SUPPORT FOR THE CRANE.]

_The Anvil-Stock_.--The anvil-stock, which is pyramidal in shape, and
the total weight of which amounts to 500 tons, is composed of superposed
courses, each formed of one or two blocks of cast iron. Each course
and every contact was very carefully planed in order to make sure of
a perfect fitting of the parts; and all the different blocks were
connected by means of mortises, by hot bandaging, and by joints with
key-pieces, in such a way as to effect a perfect solidity of the parts
and to make the whole compact and impossible to get out of shape.

The anvil-stock was afterwards surrounded by a filling-in of masonry
composed of rag-stones and a mortar made of cement and hydraulic lime.
This masonry also forms the foundation for the standards of the hammer,
and is capped with dressed stone to receive the bed-plates.

_The Power-Hammer_ (Figs. A and B).--The power-hammer, properly
so-called, consists, in addition to the hammer-head, of two standards to
whose inner sides are bolted guides upon which slides the moving mass.
The bed-plates of cast iron are 28 inches thick, and are independent of
the anvil-stock. They are set into the bed of dressed stone capping the
foundation, and are connected together by bars of iron and affixed to
the masonry by foundation bolts. To these bedplates are affixed the
standards by means of bolts and keys. The two standards are connected
together by iron plates four inches in thickness, which are set into the
metal and bolted to it so as to secure the utmost strength and solidity.
The platform which connects the upper extremities of the standards
supports the steam cylinder and the apparatus for distributing the
steam. The latter consists of a throttle valve, twelve inches in
diameter, and an eduction valve eighteen inches in diameter, the
maneuvering of which is done by means of rods extending down to a
platform upon which the engineman stands. This platform is so situated
that all orders can be distinctly heard by the engineman, and so that
he shall be protected from the heat radiated by the steel that is
being forged. All the maneuvers of the hammers are effected with most
wonderful facility and with the greatest precision.

The piston is of cast-steel, and the rod is of iron, 12 inches in
diameter. The waste steam is carried out of the mill by a pipe, and,
before being allowed to escape into the atmosphere, is directed into an
expansion pipe which it penetrates from bottom to top. Here a portion of
the water condenses and flows off, and the steam then escapes into
the open air with a greatly diminished pressure. The object of this
arrangement is to diminish to a considerable extent the shocks and
disagreeable noise that would be produced by the direct escape of the
steam at quite a high pressure and also to avoid the fall of condensed
water.

The following are a few details regarding the construction of the
hammer:

  Total height of foundations........... 26    ft.
  From the ground to the platform ...... 28     "

  Platform .............................. 3.25  "
  Height of cylinder.................... 21     "
                                         ________

      Total height...................... 78.25 ft.

  Weight of anvil-stock................ 500 tons.
  Weight of bed-plates................. 122  "
  Weight of standards.................. 270  "
  Weight of platform and cylinder...... 148  "
  Piston, valves, engineman's platform,
    hammer, etc........................ 160  "
                                        __________

      Total weight................... 1,200 tons.

  Weight of the hammer.................. 80 tons.
  Maximum fall.......................... 25.75 ft.
  Distance apart of the standards....... 21.6   "
  Width of hammer.......................  6     "
  Pressure of steam..................... 16 lb.
  Effective pressure to lift 80 tons....  7  "
_Description of Figures_.--A, the 80-ton hammer; B, B1, B2, cranes; C,
C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, the 35-ton
hammer; A2, the 28-ton hammer; EE, railways; F, engineman's platform; G,
lever for maneuvering the throttle valve; H, an ingot being forged.

       *       *       *       *       *




GREAT STEAMERS.


The _Brooklyn Eagle_ gives a very interesting description of the three
new steamships now almost completed and shortly to be placed in the New
York and Liverpool trade by the Cunard, Inman, and Williams and Guion
lines. The writer has prepared a table comparing the three vessels
with each other and with the Great Eastern, the only ship of greater
dimensions ever built. We give as much of the article as our space will
allow, and regret that we have not the room to give it entire:

     Line.         Cunard.       Inman.        Guion.    Admiralty.
    Vessel.        Servia     City of Rome.    Alaska.    Great[1]

  Length        530 feet.     546 feet.     520 feet.     679 feet.
  Breadth        52 feet.      52 ft. 3 in.  50 ft. 6 in.  82 feet.
  Depth          44 ft. 9 in.  37 feet.      38 feet.      60 feet.
  Gross ton'ge     8,500         8,300         8,000      13,344[2]
  Horse pow'r     10,500        10,000        11,000       2,600
  Speed          171/2 knots.    18 knots.     18 knots.    14 knots.
  Sal'n pas-                                 320 and 52
    sengers.       450           300          2d class
  Steerage         600         1,500         1,000
  Where          Clydeb'nk     Barrow in      Clyde,
    built.        Thomson       Furness       Elder
  Date of
    sailing.     October 22    October 13    November 5

[Footnote 1: To be sold at auction soon.]

[Footnote 2: Net register.]

In 1870 the total tonnage of British steam shipping was 1,111,375; the
returns for the year 1876 showed an increase to 2,150,302 tons, and from
that time to the present it has been increasing still more rapidly. But,
as can be seen from the above table, not only has the total tonnage
increased to this enormous extent, but an immense advance has been made
in increasing the size of vessels. The reason for this is, that it has
been found that where speed is required, along with large cargo and
passenger accommodation, a vessel of large dimensions is necessary, and
will give what is required with the least proportionate first cost as
well as working cost. Up to the present time the Inman line possessed,
in the City of Berlin, of 5,491 tons, the vessel of largest tonnage in
existence. Now, however, the Berlin is surpassed by the City of Rome by
nearly 3,000 tons, and the latter is less, by 200 tons, than the Servia,
of the Cunard line. It will be observed, too, that while there is not
much difference between the three vessels in point of length, the depth
of the Alaska and the City of Rome, respectively, is only 38 feet and 37
feet, that of the Servia is nearly 45 feet as compared with that of the
Great Eastern of 60 feet. This makes the Servia, proportionately, the
deepest ship of all. All three vessels are built of steel. This metal
was chosen not only because of its greater strength as against iron,
but also because it is more ductile and the advantage of less weight is
gained, as will be seen when it is mentioned that the Servia, if built
of iron, would have weighed 620 tons more than she does of steel, and
would have entailed the drawback of a corresponding increase in draught
of water. As regards rig, the three vessels have each a different style.
The Cunard Company have adhered to their special rig--three masts, bark
rigged--believing it to be more ship shape than the practice of fitting
up masts according to the length of the ship. On these masts there is a
good spread of canvas to assist in propelling the ship. The City of Rome
is rigged with four masts; and here the handsome full-ship rig of the
Inman line has been adhered to, with the addition of the fore and aft
rigged jigger mast, rendered necessary by the enormous length of the
vessel. It will be seen that the distinctive type of the Inman line
has not been departed from in respect to the old fashioned but still
handsome profile, with clipper bow, figurehead, and bowsprit--which
latter makes the Rome's length over all 600 feet. For the figurehead
has been chosen a full length figure of one of the Roman Caesars, in the
imperial purple. Altogether, the City of Rome is the most imposing and
beautiful sight that can be seen on the water. The Alaska has also four
masts, but only two crossed.

The length of the City of Rome, as compared with breadth, insures long
and easy lines for the high speed required; and the depth of hold being
only 37 feet, as compared with the beam of 52 feet, insures great
stability and the consequent comfort of the passengers. A point calling
for special notice is the large number of separate compartments formed
by water tight bulkheads, each extending to the main deck. The largest
of these compartments is only about 60 feet long; and, supposing that
from collision or some other cause, one of these was filled with water,
the trim of the vessel would not be materially affected. With a view to
giving still further safety in the event of collision or stranding, the
boilers are arranged in two boiler rooms, entirely separated from each
other by means of a water tight iron bulkhead. This reduces what, in
nearly all full-powered steamships, is a vast single compartment, into
two of moderate size, 60 feet in length; and in the event of either
boiler room being flooded, it still leaves the vessel with half her
boiler power available, giving a speed of from thirteen to fourteen
knots per hour. The vessel's decks are of iron, covered with teak
planking; while the whole of the deck houses, with turtle decks and
other erections on the upper deck, are of iron, to stand the strains
of an Atlantic winter. Steam is supplied by eight cylindrical tubular
boilers, fired from both ends, each of the boilers being 19 feet long
and having 14 feet mean diameter. There are in all forty eight furnaces.
The internal arrangements are of the finest description. There are two
smoking rooms, and in the after deckhouse is a deck saloon for ladies,
which is fitted up in the most elegant manner, and will prevent the
necessity of going below in showery weather. At the sides of the
hurricane deck are carried twelve life boats, one of which is fitted as
a steam launch. The upper saloon or drawing-room is 100 feet long, the
height between decks being 9 feet. The grand dining-saloon is 52 feet
long, 52 feet wide, and 9 feet high, or 17 feet in the way of the large
opening to the drawing-room above. This opening is surmounted by a
skylight, and forms a very effective and elegant relief to the otherwise
flat and heavy ceiling. There are three large and fourteen small dining
tables, the large tables being arranged longitudinally in the central
part of the saloon, and the small tables at right angles on the sides.
Each diner has his own revolving arm chair, and accommodation is
provided for 250 persons at once. A large American organ is fixed at the
fore end of the room, and opening off through double spring doors at the
foot of the grand staircase is a handsome American luncheon bar, with
the usual fittings. On each side of the vessel, from the saloon to the
after end of the engine room, are placed staterooms providing for 300
passengers. The arrangements for steerage passengers are of a superior
description. The berths are arranged in single tiers or half rooms, not
double, as is usually the custom, each being separated by a passage,
and having a large side light, thus adding greatly to the light,
ventilation, and comfort of the steerage passengers, and necessitating
the advantage of a smaller number of persons in each room. The City
of Rome is the first of the two due here; she sails from Liverpool on
October 13.

In the Servia the machinery consists of three cylinder compound surface
condensing engines, one cylinder being 72 inches, and two 100 inches in
diameter, with a stroke of piston of 6 feet 6 inches. There are seven
boilers and thirty-nine furnaces. Practically the Servia is a five
decker, as she is built with four decks--of steel, covered with yellow
pine--and a promenade reserved for passengers. There is a music room on
the upper deck, which is 50 feet by 22 feet, and which is handsomely
fitted up with polished wood panelings. For the convenience of the
passengers there are no less than four different entrances from the
upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting
accommodations for 350 persons, while the clear height under the beams
is 8 feet 6 inches. The sides are all in fancy woods, with beautifully
polished inlaid panels, and all the upholstery of the saloon is of
morocco leather. For two-thirds of its entire length the lower deck is
fitted up with first class staterooms. The ship is divided into nine
water-tight bulkheads, and she is built according to the Admiralty
requirements for war purposes. There are in all twelve boats equipped
as life-boats. The Servia possesses a peculiarity which will add to her
safety, namely, a double bottom, or inner skin. Thus, were she to
ground on rocks, she would be perfectly safe, so long as the inner skin
remained intact. Steam is used for heating the cabins and saloons, and
by this means the temperature can be properly adjusted in all weathers.
In every part of the vessel the most advanced scientific improvements
have been adopted. The Servia leaves Liverpool on October 22.

The Alaska, whose owners, it is understood, are determined to make her
beat all afloat in speed, does not sail until November 5, and therefore
it is premature to say anything about her interior equipments. She is
the sister of the celebrated Arizona, and was built by the well-known
firm of Elder & Co., on the Clyde.

       *       *       *       *       *




IMPROVED ROAD LOCOMOTIVE.


Several attempts have been made to connect the leading wheels of a
traction engine with the driving wheels, so as to make drivers of all of
them, and thus increase the tractive power of the engine, and to afford
greater facilities for getting along soft ground or out of holes. The
wheels with continuous railway and India-rubber tires have been employed
to gain the required adhesion, but these wheels have been too costly,
and the attempts to couple driving and leading wheels have failed. The
arrangement for making the leading wheels into drivers, illustrated
on page 4825, has been recently brought out by the Durham and North
Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs.
Johnson and Phillips. The invention consists in mounting the leading
axle in a ball and long socket, the socket being rotated in fixed
bearings. The ball having but limited range of motion in the socket, is
driven round with it, but is free to move in azimuth for steering.

This engine has now been in use more than twelve months in traction
and thrashing work, and, we are informed, with complete success. The
illustrations represent a 7-horse power, with a cylinder 8 in. diameter
by 12 in. stroke, and steam jacketed. The shafts and axles are of
Bowling iron. The boiler contains 140 ft. of heating surface, and is
made entirely of Bowling iron, with the longitudinal seams welded. The
gearing is fitted with two speeds arranged to travel at 11/2 and 3 miles
per hour, and the front or hind road wheels can be put out of gear when
not required. The hind driving wheels are 5 ft. 6 in. diameter, and the
front wheels 5 ft.; weight of engine 8 tons.--_The Engineer._

[Illustration: IMPROVED ROAD LOCOMOTIVE]

[Illustration: IMPROVED ROAD LOCOMOTIVE]

       *       *       *       *       *




AMERICAN MILLING METHODS.

[Footnote 1: A paper read before the meeting of the Pennsylvania State
Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the
_Northwestern Miller_.]

By ALBERT HOPPIN.


To speak of the wonderful strides which the art of milling has taken
during the past decade has become exceedingly trite. This progress,
patent to the most casual observer, is a marked example of the power
inherent in man to overcome natural obstacles. Had the climatic
conditions of the Northwest allowed the raising of as good winter wheat
as that raised in winter wheat sections generally, I doubt if we should
hear so much to-day of new processes and gradual reduction systems. So
long as the great bulk of our supply of breadstuffs came from the winter
wheat fields, progress was very slow; the mills of 1860, and I may even
say of 1870, being but little in advance, so far as processes were
concerned, of those built half a century earlier. The reason for this
lack of progress may be found in the ease with which winter wheat could
be made into good, white, merchantable flour. That this flour was
inferior to the flour turned out by winter wheat mills now is proven by
the old recipe for telling good flour from that which was bad, viz.: To
throw a handful against the side of the barrel, if it stuck there it was
good, the color being of a yellowish cast. What good winter wheat patent
to-day will do this? Still the old time winter wheat flour was the best
there was, and it had no competitor. The settling up of the Northwest
which could not produce winter wheat at all, but which did produce a
most superior article of hard spring wheat, was a new factor in the
milling problem. The first mills built in the spring wheat States tried
to make flour on the old system and made a most lamentable failure of
it. I can remember when the farmer in Wisconsin, who liked a good loaf
of bread, thought it necessary to raise a little patch of winter wheat
for his own use. He oftener failed than succeeded, and most frequently
gave it up as a bad job. Spring wheat was hard, with a very tender,
brittle bran. If ground fine enough to make a good yield a good share
of the bran went into the flour, making it dark and specky. If not
so finely ground the flour was whiter, but the large percentage of
middlings made the yield per bushel ruinously small. These middlings
contained the choicest part of the flour producing part of the berry,
but owing to the dirt, germ, and other impurities mixed with them, it
was impossible to regrind them except for a low grade flour. Merchant
milling of spring wheat was impossible wherever the flour came in
competition with winter wheat flours. At Minneapolis, where the millers
had an almost unlimited water power, and wheat at the lowest price,
merchant milling was almost given up as impracticable. It was certainly
unprofitable. To the apparently insurmountable obstacles in the way of
milling spring wheat successfully, we may ascribe the progress of modern
milling. Had it been as easy to raise good winter wheat in Wisconsin and
Minnesota as in Pennsylvania and Ohio, or as easy to make white flour
from spring as from winter wheat, we should not have heard of purifiers
and roller mills for years to come.

The first step in advance was the introduction of a machine to purify
middlings. It was found that the flour made from these purified
middlings was whiter than the flour from the first grinding and brought
a better price than even winter wheat flours. Then the aim was to make
as many middlings as possible. To do this and still clean the bran so
as to make a reasonable yield the dress of the burrs was more carefully
attended to, the old fashioned cracks were left out, the faces and
furrows made smooth, true, and uniform, self-adjusting drivers
introduced, and the driving gear better fitted. Spring wheat patents
rapidly rose to the first place in the market, and winter wheat millers
waked up to find their vantage ground occupied by their hitherto
contemned rivals. To their credit it may be said that they have not
been slow in taking up the gauntlet, and through the competition of the
millers of the two climatically divided sections of this country with
each other and among themselves the onward march of milling progress has
been constantly accelerated. Where it will end no man can tell, and
the chief anxiety of every progressive miller, whether he lives in
Pennsylvania or Minnesota, is not to be left behind in the race.

The millers of the more Eastern winter wheat States have a two-fold
question to solve. First, how to make a flour as good as can be found in
the market, and second, how to meet Western competition, which, through
cheap raw material and discriminating freight rates, is making serious
inroads upon the local markets. Whether the latter trouble can be
remedied by legislature, either State or national, or not, remains to be
proven by actual trial. That you can solve the first part of the problem
satisfactorily to yourselves depends upon your readiness to adopt new
ideas and the means you have at hand to carry them out. It is manifestly
impossible to make as good a flour out of soft starchy wheat as out of
that which is harder and more glutinous. It is equally impossible for
the small mill poorly provided with machinery to cope successfully
with the large merchant mill fully equipped with every appliance that
American ingenuity can suggest and money can buy. I believe, however,
that a mill of moderate size can make flour equally as good as the large
mill, though, perhaps, not as economically in regard to yield and cost
of manufacture.

The different methods of milling at present in use may be generally
divided into three distinct processes, which, for want of any better
names, I will distinguish as old style, new process, and gradual
reduction. Perhaps the German division of low milling, half high
milling, and high milling is better. Old style milling was that in
general use in this country up to 1870, and which is still followed in
the great majority of small custom or grist mills. It is very simple,
consisting of grinding the wheat as fine as possible at the first
grinding, and separating the meal into flour, superfine or extra,
middlings, shorts, and bran. Given a pair of millstones and reel long
enough, and the wheat could be made into flour by passing through the
two. Because spring wheat was so poorly adapted to this crude process,
it had to be improved and elaborated, resulting in the new process.

At first this merely consisted of purifying and regrinding the middlings
made in the old way. In its perfected state it may be said to be halfway
between the old style and gradual reduction, and is in use now in many
mills. In it mill stones are used to make the reductions which are only
two in number, in the first of which the aim of the miller is to make as
many middlings as he can while cleaning the bran reasonably well, and
in the second to make the purified middlings into flour. In the most
advanced mills which use the new process, the bran is reground and the
tailings from the coarse middlings, containing germ and large middlings
with pieces of bran attached, are crushed between two rolls. These
can hardly be counted as reductions, as they are simply the finishing
touches, put on to aid in working the stuff up clean and to permit of
a little higher grinding at first. Regarding both old style and new
process milling, you are already posted. Gradual reduction is newer,
much more extensive, and merits a much more thorough explanation. Before
entering upon this I will call your attention to one or two points which
every miller should understand.

The two essential qualities of a good marketable flour are color and
strength. It should be sharply granular and not feel flat and soft to
the touch. A wheat which has an abundance of starch, but is poor in
gluten, cannot make a strong flour. This is the trouble with all soft
wheats, both winter and spring. A wheat which is rich in gluten is hard,
and in the case of our hard Minnesota wheat has a very tender bran.
It is comparatively easy to make a strong flour, but it requires very
careful milling to make a flour of good color from it. Probably the
wheat which combines the most desirable qualities for flour-making
purposes is the red Mediterranean, which has plenty of gluten and a
tough bran, though claimed by some to have a little too much coloring
matter, while the body of the berry is white. By poor milling a good
wheat can be made into flour deficient both in strength and color, and
by careful milling a wheat naturally deficient in strength may be made
into flour having all the strength there was in the wheat originally and
of good color. Good milling is indispensable, no matter what the quality
of the wheat may be.

The idea of gradual reduction milling was borrowed by our millers from
the Hungarian mills. There is, however, this difference between the
Hungarian system and gradual reduction, as applied in this country, that
in the former, when fully carried out, the products of the different
breaks are kept separate to the end, and a large number of different
grades of flour made, while in the system, as applied in this country,
the separations are combined at different stages and usually only three
different grades of flour made, viz.: patent, baker's, or as it is
termed in Minnesota, clear flour, and low grade or red dog. In the
largest mills the patent is often subdivided into first and second, and
they may make different grades of baker's flour, these mills approaching
much nearer to the Hungarian system, though modifying it to American
methods and machinery. In mills of from three to five hundred barrels
daily capacity, it is hardly possible or profitable to go to this
subdivision of grades, owing to the excessive amount of machinery
necessary to handling the stuff in its different stages of completion.
The Hungarian system has, therefore, been greatly modified by American
millers and milling engineers to adapt it to the requirements of mills
of average capacity. This modified Hungarian system we call gradual
reduction. It can be profitably employed in any mill large enough to run
at all on merchant work. So far it has not been found practicable to use
it in mills of less than one hundred and twenty-five to one hundred and
fifty barrels capacity in twenty-four hours, and it is better to have
the mill of at least double this capacity.

Gradual reduction, as its name implies, consists in reducing the
wheat to flour, shorts, and bran, by several successive operations or
reductions technically called breaks, the process going on gradually,
each break leaving the material a little finer than the preceding one.
Usually five reductions or breaks are made, though six or seven may be
used. The larger the number of breaks the more complicated the system
becomes, and it is preferable to keep it as simple as possible, for even
at its simplest it requires a good, wide-awake thinking miller to handle
it successfully. When it is thoroughly and systematically carried out in
the mill it is without question as much in advance of the new process as
that is ahead of the old style of milling.

In order that I may convey to you as clear an idea of gradual milling
reduction as possible, I will give as fully as possible the programme of
a mill of one hundred and fifty barrels maximum daily capacity designed
to work on mixed hard and soft spring wheat, and which probably will
come much nearer to meeting the conditions under which you have to mill
than any other I have found readily obtainable. I have chosen a mill of
this size, first, because following out the programme of a larger one
would require too much time and too great a repetition of details and
not give you any clearer idea of the main principles involved, and
secondly, because I thought it would come nearer meeting the average
requirements of the members of your association. Your worthy secretary
cautioned me that I must remember that I was going to talk to winter
wheat millers. The main principles and methods of gradual reduction are
the same, whether applied to spring or winter wheat; the details may
have to be varied to suit the varying conditions under which different
mills are operated. For this programme I am indebted to Mr. James Pye,
of Minneapolis, who is rapidly gaining an enviable and well deserved
reputation as a milling engineer, and one who has given much study to
the practical planning and working of gradual reduction mills.

And right here let me say that no miller should undertake to build
a gradual reduction mill, or to change over his mill to the gradual
reduction system, until he has consulted with some good milling engineer
(the term millwright means very little nowadays), and obtained from him
a programme which shall fit the size of the mill, the stock upon which
it has to work, and the grade of flour which it is to make. This
programme is to the miller what a chart is to the sailor. It shows him
the course he must pursue, how the stuff must be handled, and where it
must go. Without it he will be "going it blind," or at best only feeling
his way in the dark. A gradual reduction mill, to be successful, must
have a well-defined system, and to have this system, the miller must
have a definite plan to work by. But to go on with my programme.

The wheat is first cleaned as thoroughly as possible to remove all
extraneous impurities. In the cleaning operations care should be taken
to scratch or abrade the bran as little as possible, for this reason:
The outer coating of the bran is hard and more or less friable. Wherever
it is scratched a portion is liable to become finely comminuted in the
subsequent reductions, so finely that it is impossible to separate it
from the flour by bolting, and consequently the grade of the latter is
lowered. The ultimate purpose of the miller being to separate the flour
portion of the berry from dirt, germ, and bran it is important that he
does not at any stage of the process get any dirt or fine bran speck or
dust mixed in with his flour, for if he does he cannot get rid of it
again. So it must be borne in mind that at all stages of flouring, any
abrasion or comminution of the bran is to be avoided as far as possible.

After the wheat is cleaned, it is by the first break or reduction split
or cut open, in order to liberate the germ and crease impurities. As
whatever of dirt is liberated by this break becomes mixed in with the
flour, it is desirable to keep the amount of the latter as small as
possible. Indeed, in all the reductions the object is to make as little
flour and as many middlings as possible, for the reason that the latter
can be purified, while the former cannot, at least by any means at
present in use. After the first break the cracked wheat goes to a
scalping reel covered with No. 22 wire cloth. The flour, middlings,
etc., go through the cloth, and the cracked wheat goes over the tail of
the reel to the second machine, which breaks it still finer. After this
break the flour and middlings are scalped out on a reel covered with
No. 22 wire cloth. The tailings go to the third machine, and are still
further reduced, then through a reel covered with No. 24 wire cloth. The
tailings go to the fourth machine, which makes them still finer, then
through a fourth scalping reel the same as the third. The tailings from
this reel are mostly bran with some middlings adhering, and go to the
fifth machine, which cleans the bran. From this break the material
passes to a reel covered with bolting cloth varying in fineness from No.
10 at the head to No. 00 at the tail. What goes over the tail of this
reel is sent to the bran bin, and that which goes through next to the
tail of the reel, goes to the shorts bin. The middlings from this reel
go to a middlings purifier, which I will call No. 1, or bran middlings
purifier. The flour which comes from this reel is sent to the chop reel
covered at the head with say No. 9, with about No. 5 in the middle and
No 0 at the tail. You will remember that after each reduction the flour
and middlings were taken out by the scalping reels. This chop, as it is
now called, also goes to the same reel I have just mentioned. The
coarse middlings which go over the tail of this reel go to a middlings
purifier, which I will designate as No. 2. These go through the No. 0
cloth at the tail of the reel purifier No. 3; those which go through No.
5 cloth got to purifier No. 4; while all that goes through the No. 9
cloth at the head of the reel is dropped to a second reel clothed with
Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from
this reel goes to the baker's flour packer; that which drops through the
No. 10 is sent to the middlings stone, while that which goes over the
tail of the reel goes to purifier No. 4. We have now disposed of all the
immediate products of the first five breaks, tracing them successively
to the bran and shorts bins, to the baker's flour packer and to the
middlings purifiers, a very small portion going to the middlings stone
without going through the purifiers.

The middlings are handled as follows in the purifiers. From the No. 1
machine, which takes the middlings from the fifth break, the tailings go
to the shorts bin, the middlings which are sufficiently well purified go
to the middlings stone, while those from near the tail of the machine
which contain a little germ and bran specks go to the second germ rolls,
these being a pair of smooth rolls which flatten out the germ and crush
the middlings, loosening adhering particles from the bran specks. From
the second germ rolls the material goes to a reel, where it is separated
into flour which goes into the baker's grade, fine middlings which are
returned to the second germ rolls at once, some still coarser which go
to a pair of finely corrugated iron rolls for red dog, and what goes
over the tail of the reel goes to the shorts bin. The No. 2 purifier
takes the coarse middlings from the tail of the first or chop reel as
already stated. The tailings from this machine go to the shorts bin,
some few middlings from next the tail of the machine are returned to the
head of the same machine, while the remainder are sent to the first germ
rolls. The reason for returning is more to enable the miller to keep a
regular feed on the purifiers than otherwise. The No. 3 purifier takes
the middlings from the 0 cloth on the chop reel. From purifier No. 3
they drop to purifier No. 5. A small portion that are not sufficiently
well purified are returned to the head of No. 3, while those from the
head of the machine, which are well purified, are sent to the middlings
stones. The remainder, which contain a great deal of the germ, are taken
to the first germ rolls, in passing which they are crushed lightly to
flatten the germ without making any more flour than necessary. The No. 4
purifier takes the middlings from No. 2 and also from No. 5 cloth on
the chop reel and from the No. 10 on the tail of the baker's reel. The
middlings from the head of this machine go to the middlings stones, and
the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6
go to the red dog rolls. A small portion not sufficiently well purified
are returned from No. 6 to the head of No. 4, while the cleaned
middlings go to the middlings stones.

The portions of the material which have not been traced either to the
baker's flour or the bran and shorts bins are the middlings which have
gone to the middlings stones, the germy middlings which have gone to the
first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6,
and some little stuff not quite poor enough for shorts from the reel
following the second germ rolls. Taking these _seriatim_: the middlings
after passing through the middlings stones, go to the first patent reel
covered with eleven feet of No. 13 and four feet of No. 8. The flour
from the head of the reel goes to the patent packer, that from the
remainder of the reel is dropped to another reel, while the tailings go
to the No. 4 purifier. The lower patent reel is clothed with No. 14 and
two feet of No. 10 cloth; from the head of the reel the flour goes to
the patent packer, the remainder that passes through the No. 10 cloth
which will not do to go into the patent, being returned to the middlings
stones, while the tailings are sent to the No. 4 purifier.

The germ middlings, after being slightly crushed as before stated, are
sent to a reel covered with five feet of No. 13 cloth, five feet of No.
14, and the balance with cloth varying in coarseness from No. 7 to No.
00. The flour from this reel goes into the patent, the tailings to the
red dog rolls, the middlings from next the tail of the reel which still
contain some germ to the second germ rolls, while the middlings which
are free from germ go to the middlings stones.

The tailings from purifiers 3, 4, 5, and 6, the material from the reel
following the second germ rolls, which is too good for shorts, but not
good enough to be returned into middlings again, and the tailings from
the reel following the first germ rolls are sent to the red dog rolls,
which, as I have stated, are finely corrugated. Following these rolls is
the red dog reel. The flour goes to the red dog bin, the tailings to
the shorts bin, while some stuff intermediate between the two, not fine
enough for the flour but too good for shorts, is returned to the red dog
rolls.

This finishes the programme. I have not given it as one which is exactly
suited to winter wheat milling. However, as I said before, the general
principles are the same in either winter or wheat gradual reduction
mills, and the various systems of gradual reduction, although they
differ in many points, and although there are probably no two engineers
who would agree as to all the details of a programme, the main ideas
are essentially the same. The system has been well described as one of
gradual and continued purification. In the programme above given the
idea was to fit up a mill which should do a maximum amount of work of
good quality with a minimum amount of expenditure and machinery. In a
larger mill or even in a mill of the same capacity where money was not
an object, the various separations would probably be handled a little
differently, the flour and middlings from the first and fifth breaks
being handled together, and those from the second, third, and fourth
breaks being also handled together. The reason for this separation being
that the flour from the first and fifth breaks contain, the first a
great deal of crease dirt, and the fifth more bran dust than that from
the other breaks, the result being a lower grade of flour. The object
all along being to keep the amount of flour with which dirt can get
mixed as small as possible, and not to lower the grade of any part of
the product by mixing it with that which is inferior, always bearing in
mind that the aim is to make as many middlings as possible, for they can
be purified while the flour can not, and that whenever any dirt is once
eliminated it should be kept out afterwards. This leads me to say that
if a miller thinks the adoption of rolls or reduction machines is all
there is of the system, he is very much mistaken. If anything, more of
the success of the mill depends upon the careful handling of the stuff
after the breaks are made, and here the miller who is in earnest to
master the gradual reduction system will find his greatest opportunities
for study and improvement. A few years back it was an axiom of the trade
that the condition of the millstone was the key to successful
milling. This was true because the subsequent process of bolting was
comparatively simple. Now the mere making of the breaks is a small
matter compared with the complex separations which come after. In
the foregoing programme we had five breaks or successive reductions.
Although this is better than a smaller number, I will here say that
it is not absolutely essential, for very good work is done with four
breaks. The mill for which this programme was made, including the
building, cost about $15,000, and is designed to make about sixty per
cent. of patent, thirty-five per cent. of baker's, and five per cent.
of low grade, results which are in advance of many larger and more
pretentious mills.

One difficulty in the way of adapting the gradual reduction system to
mills of very small capacity is that the various machines require to be
loaded to a certain degree in order to work at their best. It is only a
matter of short time when our milling inventors will design machinery
especially for small mills; in fact they are now doing it, and every
day brings it more within the power of the small miller to improve his
manner of milling. To show what can be done in this direction I will
briefly describe a mill of about ninety barrels maximum capacity per
twenty-four hours, which is as small as can be profitably worked. I will
premise this description by saying it is designed with a view to the
greatest economy of cost, the best trade of work, and to reduce the
amount of machinery and the handling of the stuff as much as possible.
This latter point is of much importance in any mill, either large or
small, no matter upon what system it is operated, for it takes power to
run elevators and conveyors, and especially in elevating and conveying
middlings, especially those made from winter wheat, their quality is
inured and a loss incurred, by the unavoidable amount of flour made by
the friction of the particles against each other. So much is this the
case that in one of our largest mills it is deemed preferable to move
the middlings from one end of the mill to the other by means of a hopper
bin on a car which runs on a track spiked to the floor, rather than to
employ a conveyor. A mill built as I am going to describe would require
from fifty to sixty horse-power to run it, and including steam power and
building would cost from $10,000 to $12,000, according to location. I
give it as of interest to those among your number who own small mills
and may contemplate improving them.

The building is four stories high, including basement, and thirty-two
feet square. It would be some better to have it larger, but it is made
this small to show how small a space a mill of this size can be made to
occupy. No story is less than twelve feet high. The machinery Is very
conveniently arranged, and there is plenty of room all around. The
system is a modification of the gradual reduction system, the middlings
being worked upon millstones. The first break is on one pair of 9 x
18 inch corrugated iron rolls, eight corrugations to the inch, the
corrugations running parallel with the axis of the rolls. The second
break on rolls having twelve corrugations to the inch, the third
sixteen, and the fourth twenty to the inch, while the fifth break, where
the bran is finally cleaned, has twenty-four corrugations to the inch.
The basement contains the line shaft and pulleys for driving rolls,
stones, cockle machine, and separator. The only other machinery in the
basement is the cockle machine. The line shaft runs directly through
the center of the basement, the power being from engine or water wheel
outside the building. The first floor has the roller mills in a line
nearly over the line shaft below, the middlings stones, two in number,
at one side opposite the entrance to the mill, the receiving bin at
one side of the entrance in the corner of the mill, and the two flour
packers for the baker's and patent flour in the other corner. This
arrangement leaves over half of the floor area for receiving and packing
purposes. The bolting chests, one with six reel and the other with three
reel begin on the second floor and reach up into the attic. An upright
shaft from the line shaft in the basement geared to a horizontal shaft
running through the attic parallel with the line shaft below, comprise
about all the shafting there is in the mill. There is a short shaft on
the second floor from which the two purifiers on this floor and the two
in the attic are driven, and another short shaft on the first floor to
drive the packers. There are four purifiers, two on the second floor,
and two more directly over them in the attic. The elevator heads are all
directly upon the attic line shaft, and the bolting chests are driven by
uprights dropped from this shaft. The combined smutter and brush machine
is on the third floor at one end of the bolting chests and directly over
the stock hoppers. This comprises all the machinery in the mill. The
programme is about as follows:

The break reels are clothed as follows: First break No. 20, wire cloth,
second break No. 22, third break No. 24, and fourth break No. 24. The
material passing through these scalping reels, now called chop, goes to
a series of reels, the first clothed with Nos. 6, 4, and 0. The material
passing over the tail is sent to the germ purifier, that passing through
Nos. 4 and 0, to the coarse middlings purifier, and that through the No.
6 goes to the reel below clothed with Nos. 12 and 13. Some nice granular
flour is taken off from this reel; the remainder, which passes over the
tail and through the cutoffs, goes to the next reel below clothed with
Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that which
passes through the 9 goes at once to the stones without purifying, while
that which passes over the tail is sent to the fine middlings purifiers.

After the purification, the middlings are ground on stones and bolted
on Nos. 13 and 14 cloth, after having been scalped on No 8. The germ
middlings are crushed on smooth rolls and bolted on Nos. 12 and 13. What
is not crushed fine enough goes with poor tailings to the second germ
rolls, and from these to a reel by themselves or to the fifth reduction
or bran reel. A mill of this kind could be made much more perfect by an
expenditure of two or three thousands dollars more. I have instanced it
to show what can be done with gradual reduction in a very small way.

In mills of from three hundred to five hundred barrels capacity and
still larger, the programme differs considerably from that I have
sketched, the middlings being graded and handled with little, if any,
returning, and are sized down on the smooth rolls, a much larger
percentage of the work of flouring being done on millstones. For a three
hundred barrel roller mill, the following plant is requisite: five
double corrugated roller mills, five double smooth roller mills, three
pairs of four foot burrs sixteen purifiers, four wire scalping reels,
six feet long, one reel for the fifth break, one reel for low grade
flour, eight chop reels, seven reels for flour from smooth rolls, three
reels for the stone flour, two grading reels, three flour packers, and
necessary cleaning machinery. The reels are eighteen feet thirty-two
inches. The programme is necessarily more complicated.

When it comes to the machinery to be employed in making the reductions
or breaks, the miller has several styles from which to choose. Which is
best comes under the head of what I don't know, and moreover, of that
which I have found no one else who does know. Each machine has its good
points, and the mill owner must make his own decision as to which is
best suited to his purpose. The main principles involved are to abrade
the bran as little as possible while cleaning it thoroughly, and to make
as little break flour, and as many middlings as possible, the latter to
be made in such shape as to be the most easily purified. Regarding
the difference between spring and winter wheat for gradual reduction
milling, it may be stated something after this manner: Spring wheat
has a thinner and more tender bran, makes more middlings because it is
harder, and for the same reason the flour is more inclined to be coarse
and granular. In milling with winter wheat, especially the better
varieties, there will be more break flour made, the middlings will be
finer with fewer bran specks, and the bran more easily cleaned, because
it will stand harsher treatment. Winter wheat, moreover, requires more
careful handling in making the breaks, not because of the bran, but to
avoid breaking down the middlings, and making too much and too fine and
soft break flour. In order to keep the flour sharp and granular, coarser
cloths are used in bolting, and because the middlings are finer the
bolting is not so free and a larger bolting surface is required. In
milling either spring or winter wheat there should be ample purifying
capacity, it being very unwise to limit the number of machines, so that
any of them will be overtaxed. The day has gone by when one purifier
will take care of all the middlings in the mill.

There is one point which is of much interest to mill owners who wish to
change their mills over to the gradual reduction process, that is, how
far they can utilize their present plan of milling machinery in making
the change. Of course the cleaning machinery is the same In both cases,
so are the elevators, conveyors, bolting chests, etc. But to use the
millstone is a debatable question. After carefully considering the
matter I have come to the conclusion that it has its place, and an
important one at that, under the new regime, viz., that of reducing
the finer purified middlings to flour. The reason for this lies in the
peculiar construction of the wheat berry. If the interior of the berry
were one solid mass of flour, needing only to be broken up to the
requisite fineness, it could be done as well on the rolls. But instead
of this, as is well known, the flour part of the berry is made up of
a large number of granules or cells, the walls of which are cellular
tissue, different from the bran in that it is soft and white instead of
hard and dark colored. It is also fibrous to a certain extent, and when
the fine middlings are passed between the rolls instead of breaking
down and becoming finer, it has a tendency to cake up and flatten out,
rendering the flour soft and flaky. It does not hurt the color, but it
does hurt the strength. When the millstone is used in place of the roll
the flour is of equally good color, and more round and granular. I
know that in this the advocates of smooth rolls will differ from my
conclusions, but I believe that the final outcome will be the use of
millstones on the finer middlings, and in fact on all the middlings that
are thoroughly freed from the germ.

It has been said that that which a man gives the most freely and
receives with the worst grace is advice. I will, however, close with a
little of the article which may not be wholly put of place. If you have
a mill do not imagine that the addition of a few pairs of rolls, a
purifier or two, and a little overhauling of bolting-chests, is going to
make it a full-fledged Hungarian roller mill. If you are going to change
an old mill or build a new one, do not take the counsel or follow the
plans of every itinerant miller or millwright who claims to know all
about gradual reduction. No matter what kind of a mill you want to
build, go to some milling engineer who has a reputation for good work,
tell him how large a mill you want, show him samples of the wheat it
must use and the grades of flour it must make, and have him make a
programme for the mill and plan the machinery to fit it. Then have the
mill built to fit the machinery. When it starts follow the programme,
whether it agrees with your preconceived notions or not, and the mill
will, in ninety-nine cases out of one hundred, do good work.

       *       *       *       *       *


MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS.

Dotted or chenilled tulles are fabrics extensively used in the toilet
of ladies, and the ornamentation of which has hitherto been done by
the application to the tissue, by hand, either of chenille or of small
circles previously cut out of velvet. This work, which naturally takes
considerable time, greatly increases the cost price of the article.

A few trials at doing the work mechanically have been made, but without
any practical outcome. The workwomen who do the dotting are paid at
Lyons at the rate of 80 centimes per 100 dots; so that if we take
tulle with dots counter-simpled 0.04 of an inch, which is the smallest
quincunx used, and suppose that the tissue is 31 inches wide and that
the daily maximum production is one yard, we find that 400 dots at 80
centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost
of dotting per yard. It is true that the workwoman furnishes the velvet
herself.

Mr. C. Ricanet, of Lyons, has recently invented a machine with which he
effects mechanically the different operations of dotting, not only on
tulles but also upon gauzes or any other light tissues whatever, such
as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr.
Ricanet has succeeded in constructing one of those masterpieces of
wonderfully accurate mechanism of which the textile industry appears
to have the monopoly--at least it is permissible to judge so from the
remarkable inventions of Vaucanson, Jacquard, Philippe de Girard,
Heilmann, and others.

The object of this new machine, then, which has been doing its wonderful
work for a few days only, is to reproduce artificially chenille
embroidered on light tissues, by mechanically cutting out and gluing
small circles of velvet upon these fabrics.

For this purpose all kinds of velvet may be employed, and, in order to
facilitate the cutting, they are previously coated on the reverse side
with any glue or gum whatever, which gives the velvet a stiffness
favorable to the action of the punch. To effect the object desired the
apparatus has three successive operations to perform: first, cutting the
circles; second, moistening; and third, fastening down the dots upon the
tissue according to a definite order and spacing. The machine may be
constructed upon any scale whatever, although at present it is only made
for operating on pieces 31 inches wide, that being the normal width of
dotted tulles. The quincuncial arrangement of the dots is effected by
the punching, moistening, and fastening down of odd and even dots,
combined with the forward movement of the tissue to be chenilled.

The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and
3), which revolves in the direction of the arrows and passes in the
center of 80 cam-wheels, 40 of which are odd and 40 even, alternately
opposed to each other. This shaft actuates, through its two extremities,
the different combined motions in view of the final object to be
attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show
the profile of two of these opposed cam-wheels--the arrangement by means
of which two rows of dots (odd and even) are laid down upon the tissue
during one revolution of the shaft or drum, A. Each of the wheels
carries three cams (Figs. 1 and 3), the first, (_a_), corresponding to
the punching; the second, (_a'_), to the moistening, and the third,
(_a''_), to the gluing down of the dots.

The annexed figure, one-quarter actual size, shows in section the
details of the cutting mechanism. To each cam-wheel there corresponds
one punch, and the eighty punches are arranged side by side and parallel
upon a shaft, B, a spring, _b_, holding them constantly against the
circumference of the cam-wheels. In Fig. 2 only one of these details is
shown. The punching arrangement consists of an ordinary punch, _c_, of
variable diameter, screwed to the extremity of a tube, _d_, which is
itself suspended from the end of the lever, _p_, but which can receive
from it at the desired moment the pressure necessary to effect the
cutting. The vertical position of these multiple tubes is insured by
a guide, _e_, which is thoroughly indispensable. Through each of the
tubes, _d_, there passes a plunger designed for expelling from the punch
the piece that has been cut out of the velvet, and for gluing it down to
the fabric. The two small springs, _b'_ and _b''_, tend continually to
lift the tubes as well as the plunger. The whole mechanism is affixed to
solid cast-iron frames, and the machine itself may be mounted on wooden
supports or a metal frame.

The punching is effected on a bronze straight-edge, C, which slides in a
cast-iron channel, D. This presents alternately, in its movement, entire
and punctured spaces, the former for receiving the blow of the punch and
the latter for allowing passage at the desired moment to the plunger
as it goes to fasten the dots upon the tulle which is passing along
underneath the channel, D. The punching is done primarily and
principally by pressure, but, in order to facilitate the complete
detachment of filaments which might retain the punched-out piece, the
punch is likewise given at the same time a slight rotary motion, thus
imitating mechanically what is performed by hand in the maneuver of all
punches. This rotary motion is communicated to the punches by means of
levers actuated by an eccentric, E, and which move the frame, _h_, whose
bars engage with the horizontal lever, _g_, soldered to the tube, _d_,
thus causing the latter at the very moment the punch descends to revolve
from right to left. The forty punches in operation cause the frame to
return to its initial position through the action of the springs, _b'_.
We say forty, since the inventor, in principle, has admitted 80 punches,
operating 40 as odd and 40 as even; obtaining in this way a dotting in
a regular quincunx of one yard, that is to say, 80 dots arranged in two
rows on a fabric 31 inches wide. But it is evident that a much larger
quincunx may be had by putting in play only a half, a third, or a
fourth of the punches, and causing the tulle and velvet to advance
proportionally. For this purpose it is only necessary to unscrew the
punches which are not to act, and to substitute for the ratchet wheel
which controls the unrolling of the I tulle, another having a number of
teeth proportioned to the desired spacing of the dots.

The punching having been executed, and the drum, A, continuing to
revolve, the punches rise a little owing to the conformation of the
cam-wheel, and through the action of the springs, _b_, and allow the
moistener to move forward to dampen the little circles which remain at
the orifice of the punches. The moistener or dampener is a sort of pad
equal in length to the field of action of the punches, and is affixed
to a cross-bar, F, which is connected at its two extremities with the
levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or
eccentrics, H, which are mounted on the shaft of the drum, A, cause the
moistener to move forward as soon as the punches rise after operating,
and, when it arrives beneath the punches, the larger cams, _a_, of
the cam-wheels, A, press the latter upon the pad and thus effect the
dampening of the circles of velvet.

Immediately afterwards, the same eccentrics, H, acting on a lever, I,
uncover the holes in the straight-edge, C, and the channel, D. The
large cams, _a"_, of the wheel, A, then acting very powerfully upon the
respective punches, cause these latter to pass through the orifices so
that the extremity of each punch comes within about one twenty-fifth of
an inch of the fabric to be dotted. In this passage of the tube, _d_, a
small rod, _i_, connected by a lever with the plunger, _f_, is made to
abut against the guide, _e_, thus causing the descent of the plunger to
a sufficient degree to push the velvet "dot" out of the tube and to glue
it upon the fabric. The manner in which these operations are performed
being now well enough understood, let us for a moment examine the
motions of the fabrics to be cut and dotted--the first being velvet or
any other material, even metal (goldleaf, for example), and the second,
the tulle.

The latter has but one motion, and that is in the direction of its
length, while the velvet has, in addition to this same motion, another
slight one from right to left in the direction of its width in order to
diminish waste as much as possible.

The tulle to be dotted is first wound around a roller, R, from whence it
passes over the glass guide-roller, R', and between the channel, D, and
the table, T, to the roller, R", which is heated by steam.

The hot air which is radiated dries the dots, and from thence the fabric
is taken up by other rollers or by any other method. The steam roller,
R", carries at one of its extremities a ratchet wheel whose teeth vary
in number according to the greater or less rapidity with which the tulle
is unrolled. It is actuated by a lever which receives its motion from
the eccentric, K.

[Illustration: IMPROVED MACHINE FOR DOTTING TULLAND OTHER LIGHT
FABRICS.]

In the table, T, there is a rectangular receptacle, _t_, containing
rasped or powdered velvet for the purpose of forming a reverse of the
dot. This powder attaches itself to the gum and imitates on the wrong
side of the fabric a dot similar to that on the upper or right side. The
velvet is wound upon the roller, _r_, and from thence passes under the
guiding roller, _r'_, the punches, and the second roller, _r"_. These
two latter rollers are solidly connected by a straight-edge fixed at the
extremity of the lever, L, whose other end is in continuous correlation
with the eccentric, M, which controls the lateral displacements;
while the eccentric, O, actuates, by means of the screw, Q, and the
ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric,
M, is fixed upon an axle, A', which carries a wheel, U, having teeth
inclined with respect to its axis, and which derives its motion from the
Archimedean screw, N, fixed at one of the extremities of the cam-shaft,
A.

We have stated above that the maximum daily hand production of tulle
dotted in quincunxes of 0.04 of an inch is about one yard. At the rate
of 30 revolutions per minute, and for the same article as that just
mentioned, this dotting machine is capable of producing, theoretically,
360 yards per 10 hours; but practically this production is reduced to
about 250 yards, which, however, is sufficiently satisfactory.

       *       *       *       *       *




THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES.

By ERNEST EDWARDS, B.A.


A question, relative to the subject of reproducing negatives, which was
put at a meeting of one of your New York societies, prompts me to make a
few remarks on the subject.

Among the numerous and widely diversified ramifications of our business
(the Heliotype Printing Company) we have very often to reproduce and
multiply negatives in both a direct and reversed form. Various methods
for doing this have been tried, and I may here say that I am quite well
aware of all the methods that have hitherto been suggested for the
purpose, but that which I am to describe is the one to which preference
has been given, and which is that known as the carbon process.

A sheet of carbonized paper or "tissue," having been sensitized by
immersion in a bath of bichromate of potash, is dried in the dark and
placed away for future use, although it is undesirable that it be kept
for more than four or five days. This is placed in a printing frame in
contact with the negative and exposed for a few minutes, after which it
is immersed in water, squeegeed down upon a glass plate, and developed
with warm water in the way so well known to carbon printers. The result
is a transparency which, owing to having received a sufficient exposure,
should show every detail of the negative. The nature of the tissue
employed for such a purpose must be such as to give no strong contrasts,
but everything reproduced with soft and fine gradation of tone.

The transparency thus obtained forms the _cliche_ by which the negatives
are subsequently made; and a negative of any size may be obtained by
the camera on wet or dry plates. The transparency must, of course, be
pointed to the sky and the light transmitted through it, no other light
being allowed to reach the lens except that which passes through the
carbon transparency. Care must also be taken that the transparency is
_uniformly_ lighted. If it is not possible to obtain a northern light,
which is best, a reflector of white paper or card may be used which must
be sufficiently large and placed at an angle of about forty-five degrees
to the transparency.

If the repeated negative is to be of the same size as the original it
may be readily produced by repeating the operation of printing on carbon
tissue, using the transparency in place of the negative, or using a dry
plate in place of the tissue. But on the whole I have satisfied myself
that the best results are to be obtained by the first method. There is
a greater softness in the latter method, but a greater character and
similarity to the original in the former method. There is no doubt that
the use of the carbon transparency removes the hardness and riffidness
of the outlines peculiar to the older method of a collodion
transparency, while with carbon as the medium it is difficult for
any but the most experienced eye to distinguish the copy from the
original.--_Photo Times._

       *       *       *       *       *




A NEW METHOD OF MAKING GELATINE EMULSION.


Since gelatine emulsion first came into use one of the greatest troubles
in connection with the manufacture of it has been that of washing.
According to the first methods the time taken for this part of the
process was, I believe, about twenty-four hours. It was very much
reduced and the ease of manufacture greatly facilitated by the methods
now most generally used, and which were, I believe, first communicated
by Messrs. Wratten and Wainright. I refer to those of precipitating with
alcohol and of straining the emulsion, when set, through canvas, so
as to divide it very finely. When the latter method is resorted to a
comparatively short time is sufficient to wash it. This method, although
a great improvement upon the older ones, yet leaves much to be desired,
especially for those who are not in the habit of making emulsion
regularly, but only an occasional batch. When the weather is at all warm
it takes a long time for the emulsion to set, unless ice be used, and
when once it is set the washing process is an exceedingly "messy" one
unless the water be cooled with ice; and the amount of water taken up
during washing is often so great that there is considerable difficulty
in getting the emulsion to set on the plates. In fact, even in cold
weather, it is not an easy process to conduct in the necessary near
approach to total darkness.

Considerable suspicion has of late been thrown upon the thoroughness of
the alcohol method, unless the emulsion has, previous to precipitation,
been freed of the greater part of the soluble salts by washing; that is
to say, it is doubtful whether the whole of the soluble salts can be
eliminated by the process, and, therefore, unless in exceptionally hot
weather, it would seem best not to trust to it, except as a further
security against soluble bromide and nitrate after washing. Besides
this, the consumption of alcohol is very large. Almost three times the
amount of the emulsion precipitated is required, and this, even when
methylated spirit is used, adds considerably to the expense. With a view
of doing away with the washing altogether, or, rather, of washing of
the silver bromide when not incorporated with the gelatine, several
processes have been invented. By these silver bromide is obtained in a
very fine state of division, ready to mix with gelatine and water in any
proportion.

The best known of them is Captain Abney's very ingenious glycerine
method, which seems to have been thoroughly successful in his hands,
although it has not been in every one's. The silver bromide obtained by
his process is not highly sensitive, and requires boiling with gelatine
before it is in a fit state to make a rapid plate.

We have lately had described in these columns a method of obtaining
bromide in a highly-sensitive state by means of the use of an acid,
whereby, after emulsifying and boiling, the viscosity of the gelatine
was destroyed, and the bromide in time deposited itself. During the late
hot weather, when washing became almost impossible, I was led to cast
about for some method of eliminating the soluble salts less tedious and
"sloppy" than that of washing, more certain and less expensive than that
of precipitating the whole of gelatine with alcohol, and which would
take less time than the method of obtaining the bromide in a pure form.

My first idea was to make up the solutions used in emulsifying in a very
concentrated form, and, after emulsifying, boiling, and allowing to
cool, to add to the thin emulsion thus obtained gelatine to the amount
of twenty grains to the ounce, and to precipitate this with alcohol,
the rest of the gelatine required to make up the bulk being afterwards
added, and the whole thoroughly incorporated by warming and shaking.
I was thus successful in reducing the amount of alcohol required to
one-third of what would be necessary if the whole of the emulsion were
precipitated; but still I found that, if a reliable emulsion were
required, the pellicle as formed had to be washed to free it from the
last trace of soluble salts.

It now struck me that it might be possible to precipitate the bromide of
silver direct from a very weak solution of gelatine, and obtain it in
such a form that it might be filtered, washed, and in every way treated
as an ordinary precipitate. I tried the following experiment. I took--

    1. Silver nitrate....................... 200  grains
        Water...............................   11/2 ounce.
    2. Ammonia bromide...................... 120  grains.
       Water................................   11/2 ounce.
       Gelatine.............................  12  grains.

I emulsified the two together in the usual way, allowed the whole
to cool, and then poured the thin emulsion into about ten ounces
of alcohol, stirring the while. As I had anticipated, a flocculent
precipitate was formed, which settled to the bottom of the vessel in a
few minutes. This was, in fact, sensitive bromide of silver mixed with
a very small quantity of gelatine (about five per cent.), and could, I
found, be treated in the same manner as a bromide precipitate from
an aqueous solution; it might be washed, either by decantation or by
filtration, easily dried, and doubtless could, when dry, be kept for an
indefinite time, and be at any time used by mixing with gelatine and
water in any proportion thought fit.

I found that a less amount of gelatine than four grains to the ounce was
sufficient to carry the bromide down, while five grains to the ounce
carried it down in something which I considered too near an approach to
a plastic mass.

It will be noticed that in the experiments which I have described the
emulsion had not been boiled, so that the sensitiveness of the bromide
was probably not great. As the experiment was done in daylight it was
of no practical use for making emulsion; but I have since made several
batches in this manner and have found them most satisfactory.

When sensitiveness is sought by boiling I rind it necessary to add a
small quantity of gelatine after boiling and before precipitating, as
that which has been kept for some time at a high temperature seems to
have lost the viscosity necessary to carry down the silver bromide in
such a form that it can he easily separated from the alcohol and water.

The practical manner of making an emulsion by this method may be as
follows. Make up the following mixtures:

  I.
  Silver nitrate...........................................400 grains.
  Water..................................................... 3 ounces.

  II.

  Ammonia bromide..........................................240 grains.
  Gelatine..................................................24 grains
  Water..................................................... 3 ounces.
  Hydrochloric acid enough to slightly acidify the solution.

  III.
  Gelatine................................................. 20 grains.
  Water....................................................  1/2 ounce.
  IV.

  Hard gelatine (say Nelson's X opaque,
  or Mr. A. L. Henderson's)................................240 grains.
  Soft gelatine (Nelson's No.1)........................... 240 grains.
  Water.....................................................24 ounces.

Nos. II., III., and IV. are allowed to stand until the gelatine is
softened. No. I is then warmed in a hock bottle until the gelatine is
just melted, when No. II. is poured into it, a little at a time, with
vigorous shaking, until the whole is emulsified. It is then transferred
to an ordinary jelly can, which is placed in a saucepan half full of
water over a ring Bunsen burner in the dark room, and boiled for half an
hour. It is then allowed to cool to about 100 deg. Fahr., when No. III. is
added. The whole is then allowed to get quite cool, when it is poured,
with stirring, into about one pint of methylated spirit. If it be wished
the precipitate may now be filtered out and washed at once like an
ordinary filtrate, but I prefer to allow it to settle, which it will do
in about five minutes. The supernatant fluid is then gently poured off.

This fluid will have the appearance of still containing a considerable
amount of the silver bromide; but if it be kept and filtered it will be
seen that the quantity is really so small that it may be disregarded. We
all know what an alarming quantity of silver seems to be going down the
sink when we wash vessels to which a very small quantity of emulsion is
adhering. If filtering be resorted to the liquid which comes through
will be quite clear. This was somewhat unexpected by me, as, if an
emulsion containing the whole of the gelatine be precipitated into
alcohol in the usual way, the alcohol becomes milky with a substance
which could not, I imagine, be filtered from it.

Two or three ounces of methylated spirit are now added to the vessel
containing the silver bromide, and the latter well mixed with it. This
makes the precipitate "firmer"--if such an expression be allowable--and
this time it will sink to the bottom almost immediately after the
stirring has ceased, and the alcohol may be poured off.

I consider that the bromide in this state is practically free from
soluble salts, but it may be washed with one or two changes of water if
desired.

No. IV. is now gently heated till the gelatine is melted and the
precipitate mixed with it. It must be kept warm for some time, and
shaken vigorously until all granularity has disappeared, This is, of
course, ascertained by placing a drop of the emulsion on a piece of
glass, and examining it. If it be wished to keep the bromide of silver
for future use it may be placed on a piece of muslin stretched in the
drying-box, when it will dry in a very short time; and, although I
cannot speak from experience on this point, it will, I have no doubt,
keep for an indefinite time so long as light is kept from it.

If it be desired the ammonio-nitrate method may be used instead of the
boiling one, although in my hands it does not give such sensitiveness.
If it be desired to use this method, solution Nos. I, II., and IV. are
made up exactly as for the boiling method, except that No. II. is not
acidified. Liquid ammonia is then poured with stirring into the silver
solution, until it blackens and again clears. Emulsification is
performed exactly as described above, but instead of boiling, the
emulsion is kept at a temperature of about 100 deg. Fahr. for half an hour,
when it is poured into the alcohol, no addition of gelatine being
previously made.

I think I may claim for the method which I have just described that it
is less troublesome and more certain than either the ordinary washing
method or the usual one of precipitating with alcohol, while it affords
an easy method of making sensitive silver bromide in such a form that it
can be more easily stored and afterwards manipulated than if it were in
the form of pellicle. The whole of the soluble salts are eliminated,
and also any gelatine which may have been destroyed in the cooking.
The amount of alcohol used is comparatively small; in fact, to prepare
silver bromide for a pint of emulsion very little more than a pint of
methylated spirit is required. Besides this I do not think that I would
be wrong in saying that the chance of green fog is reduced to a minimum.

Let me take this opportunity of thanking Captain Abney for his prompt
reply to my question about the connection between the proportion
of bromide to gelatine in emulsions, and the density of resulting
images.--_W. K. Burton, in British Journal of Photography_.

       *       *       *       *       *

[Illustration: Old Wrought Iron Gates, Guildhall.]

       *       *       *       *       *




THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN.


Japanese chronicles claim that the first pottery was made in the year
660 B.C.; it was not, however, until the Christian era that the art made
any considerable advances. In the year 1223 A.D., great improvements
were made in manufacture and decoration of the ware. From that date to
the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto,
Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was
first made at Kioto, at the commencement of the sixteenth century. The
best old Hizen ware, that which is still the most admired, was made
at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592.
Consul-General Van Buren states that porcelain clays are found in nearly
all parts of the country, and the different kinds are usually found
in close proximity, and close to canals and rivers, which is of
considerable advantage, as affording a means of transport. In all cases
every variety of clay used in the manufacture of pottery is found in a
natural state; there is no necessity to manufacture the quartzose or
fusible clays as is done in other parts of the world, and which adds
considerably to the cost of the ware. One of the peculiarities in the
clay found in Japan is that it contains both the fusible and infusible
materials in such proportions as to make a light, beautiful,
translucent, and durable porcelain. At Arita, in Hizen, there is a clay
found which contains 783/4 per cent, of silica, and l73/4 per cent, of
alumina; from this clay is made the delicate, translucent eggshell ware,
without the addition of any other matter. From an adjoining bluff a clay
is taken which has 50 per cent, of silica, and 38 per cent, of alumina;
from this the common porcelain is made.

Potter's clay is found in very large quantities in the provinces of
Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi,
and Mino. In the whole of Japan there are 283 localities where the clay
is deposited; many of these only furnish inferior clays, but they are
all fitted for use in some of the various kinds of pottery. These clays
are thoroughly powdered by means of what is called "balance pounders,"
worked in some localities by water-power, but the work is often done by
hand. The powder is then dried, and stored on boards or in flat boxes.
This dough does not go through the process of fermentation. The shaping
is almost exclusively done on the potter's wheel, which is set on a
pivot working in a porcelain eye. As a rule, the wheel is turned by the
potter himself, but in Hizen it is kept in motion by means of a band
connected with its pivot and another wheel turned by a boy. In making
dishes of other shape than round, a crude mould is sometimes used. After
the clay has been shaped on the wheel, it is set away for drying, and
usually in two or three days it is considered sufficiently dry for
smoothing, which is done on the wheel with a sharp curved knife. The
material is now made into "bisque," or biscuit, by a preliminary baking
in small ovens, when it is ready for painting, if it is to be painted
on the biscuit; if not, it is ready for the glazing. In either event it
will then go to the large furnace for the final baking. The kilns for
this purpose are always built on hill sides, and are joined together,
increasing in size from the lower to the higher ones, and in number from
four to twenty five; these kilns are so constructed that the draught is
from the lowest one, in addition to which each kiln has its own firing
place. The result of this construction is that the upper ones are by
far the most heated, and the ware is arranged accordingly; that which
requires the least baking, in the lower kiln, and that which requires
the greatest heat, in the upper. These connecting kilns have the merit
of being heat saving, but they are usually small and badly constructed,
and the heat in none of them is uniform.

The glaze is made from the silicious clay and potash extracted from wood
ashes. This potash is not a pure white, and this accounts for the dirty
color usually to be observed in unpainted Japanese ware. In different
districts the painting varies. For instance, in Owari, the greater part
of the ware is painted a cobalt blue--the cobalt ore being found in the
bluffs near the clay deposits, and is used for painting the cheaper
wares, and for this purpose German cobalt is also employed. The painting
with cobalt is generally done on the biscuit before glazing. In several
districts a very handsome ware is made, and painted on the glaze. For
this kind of painting the colors are mixed with a silicate of lead
and potash, and baked the third time in a small furnace at a low
temperature. The coloring oxides in use are those of copper, cobalt,
iron, antimony, manganese, and gold. Japanese porcelain painting may be
divided into two categories, decorative and graphic; the first is used
to improve the vessel upon which it is placed, and this class includes
all the ware except that of the province of Kaga, which would come under
the head of graphic, as it delineates all the trades, occupations,
sports, customs, and costumes of the people, as well as the scenery,
flora, and fauna of the country. "Owari ware" is made in the province
of that name; it is not as translucent, but stronger and more tenacious
than some of the Hizen manufacture.

The principal potteries are at a village called Seto, twelve miles from
the sea; in this village there are more than 200 kilns. The ware is
mostly painted a cobalt blue, and is merely of a decorative kind,
consisting of branches of trees, grass, flowers, birds, and insects, all
these being copied by the artist from nature. All the Owari ware is true
hard porcelain, and is strong and durable. In Hizen, a number of wares
are manufactured, the best known kind being the "Eurari," which is made
at Arita, but painted at Eurari. The colors in use are red, blue, green,
and gold; these are combined in various proportions, but, as a rule, the
red predominates. Generally the surface of the vessel is divided into
medallions of figures, which alternately have red, blue, or white
back-ground, with figures in green or blue and gold.

The egg-shell porcelain sold at Nagasaki is made in this province from
Arita clay, and this is made from clay with no admixture of fusible
matter except that contained by the clay naturally. The province of
Satsuma is noted for crackled ware. It is only within a very few years
that large vases have been manufactured, and in earlier days the old
ware was confined to small vessels. The glaze is a silicate of alumina
and potash, and the best ware has a complete network of the finest
crackles; the painting is of birds and flowers, and noted for its
delicate lines of green, red, and gold.

In Kioto, the ware manufactured is very similar to that produced in
Satsuma, but it is lighter and more porous; the decorations are also
nearly the same, being of birds and flowers. There is a description of
ware made in Kioto, called "Eraku," the whole body of which is covered
with a red oxide of iron, and over this mythical figures of gold are
traced. That produced in Kagja is _faience_, and in the style of
painting is unlike any other in Japan, the predominating color being
a light red, used with green and gold. The designs with which it is
profusely decorated are trees, grasses, flowers, birds, and figures of
all classes of people, with their costumes, occupations, and pastimes.
The "Banko" ware is made at the head of the Owari Bay; it is an unglazed
stone-ware, very light and durable, made on moulds in irregular shapes,
and decorated with figures in relief. On the island of Awadji, a
delicate, creamy, crackled, soft paste porcelain is made. The figures
used in decoration are birds and flowers, but outlined by heavy, dark
lines.

Consul Van Buren is of opinion that, at no distant day, Japan will be
one of the foremost competitors in the pottery markets of the world,
on account of the great variety and excellence of the clays, their
proximity to the sea, the cheapness of labor, and the beauty and
originality of the decorations. Already this important industry has been
greatly stimulated by the foreign demand, and by the success of
Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and
Paris.--_Journal of the Society of Arts_.

       *       *       *       *       *

Professor Julius E. Hilgard, for twenty years assistant in charge of the
office, has been placed in temporary charge of the Coast and Geodetic
Survey. It is understood that he will be appointed superintendent to
succeed the late Captain Carlile P. Patterson.

       *       *       *       *       *




THE FRENCH CRYSTAL PALACE.


The first idea of the French Crystal Palace was suggested by the English
structure of the same name at Sydenham, about eight miles from London.
Such a structure, as may be readily conceived, requires a site of vast
extent, and one that shall be easy of access and possess the most
agreeable surroundings. To the promoter of the project, those portions
of the park of St. Cloud in the vicinage of the old chateau appeared to
combine within themselves all the conditions that were desirable, and
he, therefore, on the 15th of December, 1879, addressed the Ministers of
Public Works and of Finances asking for the necessary concessions. The
extensive specifications have been finally completed and will probably
be shortly submitted for the approval of the parliament. The moment has
arrived then for the public press to take cognizance of a project which
concerns so great interests.

[Illustration: THE FRENCH CRYSTAL PALACE--PARK OF ST CLOUD, PARIS.]

At present we shall say a few words _a propos_ of the engraving we
present herewith. The French Crystal Palace will consist of one great
nave, two lateral naves, two surrounding galleries, and a vast rotunda
behind. The principal entrance, located at the head of the avenue
leading from the present ruins (which will, ere long, be transformed
into a most interesting museum), will exhibit a very striking aspect
with its monumental fountain and the dome which it is proposed to erect
over the very entrance itself. The whole structure will cover about
nineteen acres of ground, thus being two and a half times the extent of
the Palace of Industry in the Champs Elysees. The great nave of honor
will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in
height. The dome will measure exactly 328 ft. in height, or 105 ft. more
than the towers of Notre Dame. The structure, with the exception of
basement and foundation, will be of glass and iron.

The project which we publish to-day has been studied and gotten up,
according to the general plans and dimensions suggested by the promoter,
by Mr. Dumoulin, the architect. We are informed that the builder is to
be Mr. Alfred Hunnebelle, a contractor well known from the extensive
works that he has executed, and who is president of the Syndical Chamber
of Contractors of Paris.

Among the annexes of this palace we may note a "Palace of the Republic,"
to be built on the ruins and designed for illustrious or distinguished
visitors, such as the President of the Republic, the Ministers, the
Municipal Council of Paris, foreign delegates, etc.; a farm house for
special exhibitions and a field for experiments; galleries, cottages,
etc.

As for the programme, which embraces six divisions and numerous
subdivisions, we are unable to give it at present for want of space; we
need only say that it satisfies perfectly all the conditions of so vast
an undertaking.

In the hands of the projector, Mr. Nicole, who is well known from his
long experience in such matters, the exhibition will undoubtedly prove
a success and be instrumental in adding prosperity to all French
industries.

       *       *       *       *       *

THE GREAT HEAT OF THE SUN.--Prof. S. P. Langley has made the following
calculation: A sunbeam one centimeter in section is found in the clear
sky of the Alleghany Mountains to bring to the earth in one minute
enough heat to warm one gramme of water by 1 deg. C. It would, therefore,
if concentrated upon a film of water 1/500th of a millimeter thick,
1 millimeter wide, and 10 millimeters long, raise it 83 1/3 deg. in one
second, provided all the heat could be maintained. And since the
specific heat of platinum is only 0.0032 a strip of platinum of the same
dimensions would, on a similar supposition, be warmed _in one second_ to
2,603 deg. C.--a temperature sufficient to melt it!

       *       *       *       *       *




CHATEAU IN THE AEGEAN SEA.


From the site of this building, magnificent views are obtained over the
island-dotted sea and the mainland of Asia Minor: but, "though every
prospect pleases," it is a land of earthquakes, and unfortunately, the
works at the chateau have been suspended, owing to the dreadful calamity
which has recently fallen upon the district. The building is intended
for the residence of an English lady of exalted rank. It is to be built
of local white stone, the hall, staircase, etc., being lined and paved
with marbles. The hall is a large apartment about 25 ft. high, with
paneled ceiling, having galleries on two sides, giving access to the
rooms surrounding it on first floor, and to the turret staircase leading
to roofs, etc. With the exception of sanitary apparatus, painted
windows, etc. (which will be supplied by English firms), the whole of
the work will be executed by native labor. The architect is Mr. Edwin T.
Hall, London.--_Building News_.

[Illustration: SUGGESTIONS IN ARCHITECTURE--A CASTELLATED CHATEAU.]

       *       *       *       *       *




ELECTRIC POWER.


Just now nothing save electricity is talked about in scientific circles.
During the meeting of the British Association the greatest possible
prominence was given to electrical questions and propositions The
success of the electric light, the introduction of the Faure battery
with a great flourish of trumpets, and the magnificent display of
electrical instruments and machinery at Paris, have all operated to the
same end. The daily press has taken the subject up, and journals which
were nothing hitherto if not political, now indulge in magnificent
rhapsodies concerning the future of electricity. Even eminent engineers,
carried away by the intoxication of the moment, have not hesitated to
say that the steam engine is doomed, and that its place will be taken by
the electricity engine. In the midst of all this noise and clamor and
blowing of personal trumpets, it is not easy to keep one's head clear,
and mistakes may be made which will cause disappointment to many and
retard the progress of electrical science. We confidently expect that
electricity will prove a potent agent by and by in the hands of the
speculator for extracting gold from the pockets of the public, and we
write now to warn our readers in time, and to endeavor to clear the air
of some of the mists with which it is obscured. There is, no doubt,
a great future before electricity; but it is equally certain that
electricity can never do many things which the half informed may be
readily made to believe it will do. We propose here to say enough
on this point to enlighten our readers, without troubling them with
perplexing problems and speculations.

No one at this moment knows what electricity is; but for our present
purpose we may regard it as a fluid, non-elastic, and without weight,
and universally diffused through the universe. To judge by recently
published statements, a large section of the reading public are taught
that this fluid is a source of power, and that it may be made to do the
work of coal. This is a delusion. So long as electricity remains in what
we may call a normal state of repose, it is inert. Before _we can get
any work out of electricity a somewhat greater amount of work must be
done upon it_. If this fundamental and most important truth be kept in
view it will not be easy to make a grave mistake in estimating the value
of any of the numerous schemes for making electricity do work which will
ere long be brought before the public. To render our meaning clearer,
we may explain that in producing the electric light, for instance, a
certain quantity of electricity passes in through one wire to the lamp,
and precisely the same quantity passes out through the other wire, and
on to the earth or return wire completing the circuit. Not only is the
quantity the same, the velocity is also unchanged. But in going through
the lamp the current has done something. It has overcome the resistance
of the carbons, heated them to a dazzling white heat, and so performed
work. In doing this the current of electricity has lost something. Led
from the first lamp to a second, it is found powerless--if the first
lamp be of sufficient size. What is it that the electricity has lost?
It has parted with what electricians would term "potential," or the
capacity for performing work. What this is precisely, or in what way the
presence or absence of potential modifies the nature of the electric
current, no one knows; but it is known that this potential can only be
conferred on electricity by doing work on the electricity in the first
instance. The analogy between electricity and a liquid like water will
now be recognized. So long as the water is at rest, it is inert. If we
pump it up to a height, we confer on it the equivalent of potential.
We can let the water fall into the buckets of an overshot wheel. Its
velocity leaving the tail race may be identical with that at which it
left the supply trough to descend on the wheel. Its quantity will be
the same. It will be in all respects unchanged, just as the current
of electricity passing through a lamp is unchanged; but it has,
nevertheless, lost something. It has parted with its potential--capacity
for doing work--and it becomes once more inert. But the duty which it
discharged in turning the mill wheel was somewhat less than the precise
equivalent of the work done in pumping it up to a level with the top of
the wheel. In the same way the electric current never can do work equal
in amount to the work done on it in endowing it with potential.

It will thus be seen that electricity can only be used as a means of
transmitting power from one place to another, or for storing power up
at one time to be used at a subsequent period; but it cannot be used to
originate power in the way coal can be used. It possesses no inherent
potential. It is incapable of performing work unless something is done
to it first. We have spoken of it as a fluid, but only for the sake of
illustration. As we have said, no one knows what it is, but the theory
which bids fair for acceptance is that it is a mode of motion of the
all-pervading ether. Very curious and instructive experiments are now
being carried out in Paris by Dr. Bjerkness, of Christiania, in the
Norwegian section of the electrical exhibition. This gentleman submerges
thin elastic diaphragms in water, and causes them to vibrate, or rather
pulsate, by compressed air. He finds that if they pulsate synchronously
they attract each other. If the pulsations are not simultaneous, the
disks repel each other. From this and other results he has obtained,
it may be argued that the ether plays the part of the water in Dr.
Bjerkness' tank, and that when special forms of vibration are set up
in bodies they become competent to attract or repel other bodies. This
being so, it will be seen that the power of attraction or repulsion of
an electrical body depends in the first instance on the motion set up
in the body attracted or repulsed, and this motion is, of course, some
function of the work originally done on the body. We need not pursue
this argument further. Among the most scientific investigators of the
day it is admitted that the efficiency of electricity as a doer of work,
or a producer of action at a distance, must depend for its value on the
performance of work in some one way or another on the electricity itself
in the first instance. It may be worth while here to dispel a popular
delusion. It is held very generally that electricity can be made, as,
for instance, by the galvanic battery. There is no reason to believe
anything of the kind; but whether it is or is not true that electricity
is actually made by the combustion of zinc in a galvanic trough, it is
quite certain that this electricity, unless it possesses potential, can
do no work, no matter how great its quantity. Of course, it is to be
understood that all electric currents possess potential. If they did
not, their presence would be unknown; but the potential of a current
is in all cases the result of work done on electricity, either by the
oxidation of zinc, or in some other way. This is a broad principle, but
it is strictly consistent in every respect with the truth. Electricity,
then, is, as we have said, totally different from coal; and it can never
become a substitute for it alone. Water power, air power, or what we
may, for want of a better phrase, call chemical power, combined with
electricity, can be used as a substitute for coal; but electricity
cannot of itself be employed to do work. It is true, however, that
electricity, on which work has already been done, may be found in
nature. Atmospheric electricity, for example, may perhaps yet be
utilized. It is by no means inconceivable that the electricity contained
in a thunder cloud might be employed to charge a Faure battery; but up
to the present no one has contemplated the obtaining of power from the
clouds, and whether it is or is not practicable to utilize a great
natural force in this way does not affect our statement. The use of
electricity must be confined to its power of transmitting or storing up
energy, and this truth being recognized, it becomes easy to estimate the
future prospects of electricity at something like their proper value.

It has been proved to a certain extent that electricity can be used to
transmit power to a distance, and that it can be used to store it up.
Thus far the man of pure science. The engineer now comes on the stage
and asks--Can practical difficulties be got over? Can it be made to pay?
In trying to answer these questions we cannot do better than deal with
one or two definite proposals which have been recently made. That with
which we shall first concern ourselves is that trains should be worked
by Faure batteries instead of by steam. It is suggested that each
carriage of a train should be provided with a dynamo motor, and that
batteries enough should be carried by each to drive the wheels, and so
propel the train. Let us see how such a scheme would comply with working
conditions. Let us take for example a train of fifteen coaches on the
Great Northern Railway, running without a stop to Peterborough in one
hour and forty minutes. The power required would be about 500 horses
indicated. To supply this for 100 minutes, even on the most absurdly
favorable hypothesis, no less than 25 tons of Faure batteries would be
required. Adding to these the weight of the dynamo motors, and that
unavoidably added to the coaches, it will be seen that a weight equal to
that of an engine would soon be reached. The only possible saving would
be some 28 to 30 tons of tender. In return for this all the passengers
would have to change coaches at Peterborough, as the train could not be
delayed to replace the expended with fresh batteries. This is out of
the question. The Faure batteries must all be carried on one vehicle or
engine, which could be changed for another, like a locomotive. Even then
no advantage would be gained. As to cost, it is very unlikely that the
stationary engines which must be provided to drive the dynamo machines
for charging the batteries would be more economical than locomotive
engines; and if we allow that the dynamo machine only wasted 10 per
cent. of the power of the engine, the Faure batteries 10 per cent. of
the power of the dynamo machines, and the dynamo motors 10 per cent. of
the power of the batteries--all ridiculously favorable assumptions--yet
the stationary engines would be handicapped with a difference in net
efficiency between themselves and the locomotive--admitting the original
efficiency per pound of coal in both to be the same--of some 27 per
cent., we think we may relegate this scheme to the realms of oblivion.
Another idea is that by putting up turbines and dynamo machines the
steam engine might be superseded by water power. Now it so happens that
if all the water power of England were quadrupled it would not nearly
suffice for our wants. It may be found worth while perhaps to construct
steam engines close to coalpits and send out power from these engines by
wire; but the question will be asked, Which is the cheaper of the two,
to send the coal or to send the power? On the answer to this will
depend the decision of the mill owners. Another favorite scheme is that
embodied in the Siemens electrical railway. We believe that there is a
great future in store for electricity as a worker of tramway traffic;
but the traffic on a great line like the Midland or Great Northern
Railway could not be carried on by it. As Robert Stephenson said of the
atmospheric system, it is not flexible enough. The working of points
and crossings, and the shunting of trains and wagons, would present
unsurmountable difficulties. We have cited proposals enough, we think,
to illustrate our meaning. Sir William Armstrong, Sir Frederick
Bramwell, Dr. Siemens, Sir W. Thomson, and many others may be excused if
they are a little enthusiastic. They are just now overjoyed with success
attained; but when the time comes for sober reflection they will, no
doubt, see good reason to moderate their views. No one can say, of
course, what further discoveries may bring to light; but recent speakers
and writers have found in what is known already, materials for sketching
out a romance of electricity. It is but romancing to assert that the end
of the steam engine is at hand. Wonderful and mystical as electricity
is, there are some very hard and dry facts about it, and these facts are
all opposed to the theory that it can become man's servant of all work.
Ariel-like, electricity may put a girdle round the earth in forty
minutes; but it shows no great aptitude for superseding the useful old
giant steam, who has toiled for the world so long and to such good
purpose--_The Engineer_.

       *       *       *       *       *




ON A METHOD OF OBTAINING AND MEASURING VERY HIGH VACUA WITH A MODIFIED
FORM OF SPRENGEL-PUMP.

By Ogden N. Rood, Professor of Physics in Columbia College.


In the July number of this Journal for 1880, I gave a short account of
certain changes in the Sprengel-pump by means of which far better vacua
could be obtained than had been previously possible. For example, the
highest vacuum at that time known had been reached by Mr. Crookes, and
was about 1/17,000,000, while with my arrangement vacua of 1/100,000,000
were easily reached. In a notice that appeared in _Nature_ for August,
1880, p. 375, it was stated that my improvements were not new, but had
already been made in England four years previously. I have been unable
to obtain a printed account of the English improvements, and am willing
to assume that they are identical with my own; but on the other hand,
as for four years no particular result seems to have followed their
introduction in England, I am reluctantly forced to the conclusion that
their inventor and his customers, for that period of time, have remained
quite in ignorance of the proper mode of utilizing them. Since then I
have pushed the matter still farther, and have succeeded in obtaining
with my apparatus vacua as high as 1/390,000,000 without finding
that the limit of its action had been reached. The pump is simple in
construction, inexpensive, and, as I have proved by a large number of
experiments, certain in action and easy of use; stopcocks and grease are
dispensed with, and when the presence of a stopcock is really desirable
its place is supplied by a movable column of mercury.

_Reservoir_.--An ordinary inverted bell-glass with a diameter of 100 mm.
and a total height of 205 mm. forms the reservoir; its mouth is closed
by a well-fitting cork through which passes the glass tube that forms
one termination of the pump. The cork around tube and up to the edge of
the former is painted with a flexible cement. The tube projects 40 mm.
into the mercury and passes through a little watch-glass-shaped piece of
sheet-iron, W, figure 1, which prevents the small air bubbles that creep
upward along the tube from reaching its open end; the little cup is
firmly cemented in its place. The flow of the mercury is regulated
by the steel rod and cylinder, CR, Figure 1. The bottom of the steel
cylinder is filled out with a circular piece of pure India-rubber,
properly cemented; this soon fits itself to the use required and answers
admirably. The pressure of the cylinder on the end of the tube is
regulated by the lever, S, Figure 1; this is attached to a circular
board which again is firmly fastened over the open end of the
bell-glass. It will be noticed that on turning the milled head, S, the
motion of the steel cylinder is not directly vertical, but that it tends
to describe a circle with c as a center; the necessary play of the
cylinder is, however, so small, that practically the experimenter does
not become aware of this theoretical defect, so that the arrangement
really gives entire satisfaction, and after it has been in use for a few
days accurately controls the flow of the mercury. The glass cylinder is
held in position, but not supported, by two wooden _adjustable_ clamps,
_a a_, Figure 2. The weight of the cylinder and mercury is supported by
a shelf, S, Figure 2, on which rests the cork of the cylinder; in this
way all danger of a very disagreeable accident is avoided.

[Illustration: MODIFIED FORM OF SPRENGEL PUMP.]

_Vacuum-bulb_.--Leaving the reservoir, the mercury enters the
vacuum-bulb, B, Figure 2, where it parts with most of its air and
moisture; this bulb also serves to catch the air that creeps into the
pump from the reservoir, even when there is no flow of mercury; its
diameter is 27 mm. The shape and inclination of the tube attached to
this bulb is by no means a matter of indifference; accordingly Figure
3 is a separate drawing of it; the tube should be so bent that a
horizontal line drawn from the proper level of the mercury in the bulb
passes through the point, _o_, where the drops of mercury break off. The
length of the tube, EC, should be 150 mm., that of the tube, ED, 45 mm.;
the bore of this tube is about the same as that of the fall-tube.

_Fall-tube and bends_.--The bore of the fall-tube in the pump now used
by me is 1.78 mm.; its length above the bends (U, Figure 2) is 310 mm.;
below the bends the length is 815 mm. The bends constitute a fluid valve
that prevents the air from returning into the pump; beside this, the
play of the mercury in them greatly facilitates the passage of the
air downward. The top of the mercury column representing the existing
barometric pressure should be about 25 mm. below the bends when the pump
is in action. This is easily regulated by an adjustable shelf, which is
also employed to fill the bends with mercury when a measurement is taken
or when the pump is at rest. On the shelf is a tube, 160 mm. high and 20
mm. in diameter, into which the end of the fall-tube dips; its side has
a circular perforation into which fits a small cork with a little tube
bent at right angles. With the hard end of a file and a few drops of
turpentine the perforation can be easily made and shaped in a few
minutes. By revolving the little bent tube through 180 deg. the flow of the
mercury can be temporarily suspended when it is desirable to change the
vessel that catches it.

_Gauge_.--For the purpose of measuring the vacua I have used an
arrangement similar to McLeod's gauge, Figure 4; it has, however, some
peculiarities. The tube destined to contain the compressed air has a
diameter of 1.35 mm. as ascertained by a compound microscope; it is not
fused at its upper extremity, but closed by a fine glass rod that fits
into it as accurately as may be, the end of the rod being ground flat
and true. This rod is introduced into the tube, and while the latter
is gently heated a very small portion of the cement described below is
allowed to enter by capillary attraction, but not to extend beyond the
end of the rod, the operation being watched by a lens. The rod is
used for the purpose of obtaining the compressed air in the form of a
cylinder, and also to allow cleansing of the tube when necessary. The
capacity of the gauge-sphere was obtained by filling it with mercury;
its external diameter was sixty millimeters; for measuring very high
vacua this is somewhat small and makes the probable errors rather
large; I would advise the use of a gauge-sphere of about twice as great
capacity. The tube, CB, Figure 4, has the same bore as the measuring
tube in order to avoid corrections for capillarity. The tube of the
gauge, CD, is not connected with an India-rubber tube, as is usual,
but dips into mercury contained in a cylinder 340 mm. high, 58 mm. in
diameter, which can be raised and lowered at pleasure. This is best
accomplished by the use of a set of boxes of various thicknesses, made
for the purpose and supplemented by several sheets of cardboard and even
of writing-paper. These have been found to answer well and enable the
experimenter to graduate with a nicety the pressure to which the gas is
exposed during measurement. By employing a cylinder filled with mercury
instead of the usual caoutchouc tubing small bubbles of air are
prevented from entering the gauge along with the mercury. An adjustable
brace or support is used which prevents accident to the cylinder when
the pump is inclined for the purpose of pumping out the vacuum-bulb. The
maximum pressure that can be employed in the gauge used by me is 100 mm.

All the tubing of the pump is supported at a distance of about 55 mm.
from the wood-work; this is effected by the use of simple adjustable
supports and adjustable clamps; the latter have proved a great
convenience. The object is to gain the ability to heat with a Bunsen
burner all parts of the pump without burning the wood-work. Where glass
and wood necessarily come in contact the wood is protected by metal or
simply painted with a saturated solution of alum. The glass portions
of the pump I have contrived to anneal completely by the simple means
mentioned below. If the glass is not annealed it is certain to crack
when subjected to heat, thus causing vexation and loss of time. The
mercury was purified by the same method that was used by W. Siemens
(Pogg. Annalen, vol. ex., p. 20), that is, by a little strong sulphuric
acid to which a few drops of nitric acid had been added; it was dried by
pouring it repeatedly from one hot dry vessel to another, by filtering
it while quite warm, the drying being completed finally by the action of
the pump itself. All the measurements were made by a fine cathetometer
which was constructed for me by William Grunow; see this Journal, Jan.,
1874, p. 23. It was provided with a well-corrected object-glass having a
focal length of 200 mm. and as used by me gave a magnifying power of 16
diameters.

_Manipulation_.--The necessary connections are effected with a cement
made by melting Burgundy pitch with three or four per cent of gutta
percha. It is indispensable that the cement when cold should be so hard
as completely to resist taking any impression from the finger nail,
otherwise it is certain to yield gradually and finally to give rise to
leaks. The connecting tubes are selected so as to fit as closely as
possible, and after being put into position are heated to the proper
amount, when the edges are touched with a fragment of cold cement which
enters by capillary attraction and forms a transparent joint that can
from time to time be examined with a lens for the colors of thin plates,
which always precede a leak. Joints of this kind have been in use by me
for two months at a time without showing a trace of leakage, and the
evidence gathered in another series of unfinished experiments goes to
show that no appreciable amount of vapor is furnished by the resinous
compound, which, I may add, is never used until it has been repeatedly
melted. As drying material I prefer caustic potash that has been in
fusion just before its introduction into the drying tube; during the
process of exhaustion it can from time to time be heated nearly to the
melting point: if actually fused in the drying tube the latter almost
invariably cracks. The pump in the first instance is to be inclined at
an angle of about 10 degrees, the tube of the gauge being supported by
a semicircular piece of thick pasteboard fitted with two corks into the
top of the cylinder. This seemingly awkward proceeding has in no case
been attended with the slightest accident, and owing to the presence of
the four leveling-screws, the pump when righted returns, as shown by the
telescope of the cathetometer, almost exactly to its original place. In
the inclined position the exhaustion of the vacuum bulb is accomplished
along with that of the rest of the pump. The exhaustion of the
vacuum-bulb when once effected can be preserved to a great extent for
use in future work, merely by allowing mercury from the reservoir to
flow in a rapid stream at the time that air is allowed to re-enter the
pump. During the first process of exhaustion the tube of the gauge is
kept hot by moving to and fro a Bunsen burner, and is in this way
freed from those portions of air and moisture that are not too firmly
attached. After a time the vacuum-bulb ceases to deliver bubbles of
air; it and the attached tube are now to be heated with a moving Bunsen
burner, when it will be found to furnish for 15 or 20 minutes a large
quantity of bubbles mainly of vapor of water. After then production
ceases the pump is righted and the exhaustion carried farther. In spite
of a couple of careful experiments with the cathetometer I have not
succeeded in measuring the vacuum in the vacuum bulb, but judge from
indications, that is about as high as that obtained in an ordinary
Geissler pump. Meanwhile the various parts of the pump can be heated
with a moving Bunsen burner to detach air and moisture, the cement being
protected by wet lamp-wicking. In one experiment I measured the amount
of air that was detached from the walls of the pump by heating them for
ten minutes somewhat above l00 deg. C., and found that it was 1/1,000,000
of the air originally present. I have also noticed that a still larger
amount of air is detached by electric discharges. This coincides with an
observation of E. Bessel-Hagen in his interesting article on a new form
of Toepler's mercury-pump (Annalen der Physik und Chemie, 1881, vol.
xii.). Even when potash is used a small amount of moisture always
collects in the bends of the fall tube; this is readily removed by a
Bunsen burner; the tension of the vapor being greatly increased, it
passes far down the fall-tube in large bubbles and is condensed. Without
this precaution I have found it impossible to obtain a vacuum higher
than 1/25,000,000; in point of fact the bends should always be heated
when a high exhaustion is undertaken even if the pump has been standing
well exhausted for a week; the heat should of course never be applied at
a late stage of the exhaustion. Conversely, I have often by the aid of
heat completely and quickly removed quite large quantities of the vapor
of water that had been purposely introduced. The exhaustion of the
vacuum-bulb is of course somewhat injured by the act of using the pump
and also by standing for several days, so that it has been usual with me
before undertaking a high exhaustion to incline the pump and re-exhaust
for 20 minutes; I have, however, obtained very high vacua without using
this precaution.

During the process of exhaustion not more than one-half of the mercury
in the reservoir is allowed to run out, other wise when it is returned
bubbles of air are apt to find their way into the vacuum-bulb. In order
to secure its quiet entrance it is poured into a silk bag provided with
several holes. When the reservoir is first filled its walls for a day
or two appear to furnish air that enters the vacuum-bulb; this action,
however, soon sinks to a minimum and then the leakage remains quite
constant for months together.

_Measurement of the vacuum_.--The cylinder into which the gauge-tube
dips is first elevated by a box sufficiently thick merely to close the
gauge, afterwards boxes are placed under it sufficient to elevate the
mercury to the base of the measuring tube; when the mercury has reached
this point, thin boards and card-boards are added till a suitable
pressure is obtained. The length of the inclosed cylinder of air is
then measured with the cathetometer, also the height of the mercurial
"meniscus," and the difference of the heights of the mercurial columns
in A and B, figure 4. To obtain a second measure an assistant removes
some of the boxes and the cylinder is lowered by hand three or four
centimeters and then replaced in its original position. In measuring
really high vacua, it is well to begin with this process of lowering and
raising the cylinder, and to repeat it five or six times before taking
readings. It seems as though the mercury in the tube, B, supplies to the
glass a coating of air that allows it to move more freely; at all events
it is certain that ordinarily the readings of B become regular, only
after the mercury has been allowed to play up and down the tube a number
of times. This applies particularly to vacua as high 1/50,000,000 and to
pressures of five millimeters and under. It is advantageous in making
measurements to employ large pressures and small volumes; the correct
working of the gauge can from time to time be tested by varying the
relations of these to each other. This I did quite elaborately, and
proved that such constant errors as exist are small compared with
inevitable accidental errors, as, for example, that there was no
measurable correction for capillarity, that the calculated volume of the
"meniscus" was correct, etc. It is essential in making a measurement
that the temperature of the room should change as little as possible,
and that the temperature of the mercury in the cylinder should be at
least nearly that of the air near the gauge-sphere. The computation is
made as follows

  n = height of the cylinder inclosing the air;
  c = a factor which, multiplied by n, converts it into cubic
                millimeters;
  S = cubic contents of the meniscus;
  d = difference of level between A and B, fig. 4;
    = the pressure the air is under;
  N = the cubic contents of the gauge in millimeters;
  x = a fraction expressing the degree of exhaustion obtained; then

          x=1/([N (760/d)]/[nc - S])

It will be noticed that the measurements are independent of the actual
height of the barometer, and if several readings are taken continuously,
the result will not be sensibly affected by a simultaneous change of the
barometer. Almost all the readings were taken at a temperature of about
20 deg. C., and in the present state of the work corrections for temperature
may be considered a superfluous refinement.

_Gauge correction_.--It is necessary to apply to the results thus
obtained a correction which becomes very important when high vacua are
measured. It was found in an early stage of the experiments that the
mercury, in the act of entering the highly exhausted gauge, gave out
invariably a certain amount of air which of course was measured along
with the residuum that properly belonged there; hence to obtain the true
vacuum it is necessary to subtract the volume of this air from nc. By a
series of experiments I ascertained that the amount of air introduced by
the mercury in the acts of entering and leaving the gauge was sensibly
constant for six of these single operations (or for three of these
double operations), when they followed each other immediately. The
correction accordingly is made as follows: the vacuum is first measured
as described above, then by withdrawing all the boxes except the lowest,
the mercury is allowed to fall so as nearly to empty the gauge; it is
then made again to fill the gauge, and these operations are repeated
until they amount in all to six; finally the volume and pressure are a
second time measured. Assuming the pressure to remain constant, or that
the volumes are reduced to the same pressure,

  v = the original volume;  v' = the final volume;
  V' = volume of air introduced by the first entry of the mercury;
  V = corrected volume; then

  V' = (v'-v)/6
  V = v - [(v'-v)/6]

It will be noticed that it is assumed in this formula that the same
amount of air is introduced into the gauge in the acts of entry and
exit; in the act of entering in point of fact more fresh mercury is
exposed to the action of the vacuum than in the act exit, which might
possibly make the true gauge-correction rather larger than that given by
the formula. It has been found that when the pump is in constant use the
gauge-correction gradually diminishes from day to day; in other words,
the air is gradually pumped out of the gauge-mercury. Thus on December
21, the amount of air entering with the mercury corresponded to an
exhaustion of

  1/27,308,805 .......Dec. 21.

  1/38,806,688 ...... Dec. 29.

  1/78,125,000 .......Jan. 15.

  1/83,333,333 .......Jan. 23

  1/128,834,063 ......Feb. 1.

  1/226,757,400 ..... Feb. 9.

  1/232,828,800 ..... Feb. 19.

  1/388,200,000 ......March 7.

That this diminution is not due to the air being gradually withdrawn
from the walls of the gauge or from the gauge-tube, is shown by the fact
that during its progress the pump was several times taken to pieces, and
the portions in question exposed to the atmosphere without affecting
the nature or extent of the change that was going on. I also made one
experiment which proves that the gauge-correction does not increase
sensibly, when the exhausted pump and gauge are allowed to stand unused
for twenty days.

_Rate of the pump's work_.--It is quite important to know the rate of
the pump at different degrees of exhaustion, for the purpose of enabling
the experimenter to produce a definite exhaustion with facility; also if
its maximum rate is known and the minimum rate of leakage, it becomes
possible to calculate the highest vacuum attainable with the instrument.
Examples are given in the tables below; the total capacity was about
100,000 cubic mm.

  Time.         Exhaustion.         Ratio.

                1/78,511
  10 minutes              }........ 1:1/3.53
                1/276,980
  10 minutes              }........ 1:1/6.10
               1/1,687,140
  10 minutes              }........ 1:1/4.15
               1/7,002,000

Upon another occasion the following rates and exhaustions were obtained:

  Time.         Exhaustion.         Rate.

               1/7,812,500
  10 minutes              }........ 1:1/3.18
              1/24,875,620
  10 minutes              }........ 1:1/2.69
              1/67,024,090
  10 minutes              }........ 1:1/1.22
              1/81,760,810
  10 minutes              }........ 1:1.67
             1/136,986,300
  10 minutes              }........ 1:1.23
             1/170,648,500

The _irregular_ variations in the rates are due to the mode in which the
flow of the mercury was in each case regulated.

_Leakage_.--We come now to one of the most important elements in the
production of high vacua. After the air is detached from the walls of
the pump the leakage becomes and remains nearly constant. I give below a
table of leakages, the pump being in each case in a condition suitable
for the production of a very high vacuum:

  Duration of the                           Leakage per hour in
     experiment                               cubic mm., press.,
                                                 760 mm.

      181/2 hours............................ 0.000853
      27  hours............................ 0.001565
      261/2 hours.............................0.000791
      20  hours.............................0.000842
      19  hours.............................0.000951
      19  hours.............................0.001857
       7  days..............................0.001700
       7  days..............................0.001574

                Average.................... 0.001266

I endeavored to locate this leakage, and proved that one-quarter of
it is due to air that enters the gauge from the top of its column of
mercury, thus:

  Duration of the                         Gauge-leakage per hour
    experiment.                            in cubic mm., press.
                                                  760 mm.

    18 hours.................................0.0002299
     7 days..................................0.0004093
     7 days..................................0.0003464

               Average.......................0.0003285

This renders it very probable that the remaining three quarters are due
to air given off from the mercury at B, Fig. 4, from that in the bends
and at the entrance of the fall-tube, _o_, Fig. 3.

Further on some evidence will be given that renders it probable that the
leakage of the pump when in action is about four times as great as the
total leakage in a state of rest.

The gauge, when arranged for measurement of gauge-leakage, really
constitutes a barometer, and a calculation shows that the leakage would
amount to 2.877 cubic millimeters per year, press. 760 mm. If this air
were contained in a cylinder 90 mm. long and 15 mm. in diameter it would
exert a pressure of 0.14 mm. To this I may add that in one experiment
I allowed the gauge for seven days to remain completely filled with
mercury and then measured the leakage into it. This was such as would
in a year amount to 0.488 cubic millimeter, press. 760 mm., and in a
cylinder of the above dimensions would exert a pressure of 0.0233 mm.

_Reliability of the results: highest vacuum._

The following are samples of the results obtained. In one case sixteen
readings were taken in groups of four with the following result:

        Exhaustion.
       1 / 74,219,139
       1 / 78,533,454
       1 / 79,017,272
       1 / 68,503,182
  Mean 1 / 74,853,449

Calculating the probable error of the mean with reference to the above
four results it is found to be 2.28 per cent of the quantity involved.

A higher vacuum measured in the same way gave the following results:

  1 / 146,198,800
  1 / 175,131,300
  1 / 204,081,600
  1 / 201,207,200

The mean is 1 / 178,411,934, with a probable error of 5.42 per cent of
the quantity involved. I give now an extreme case; only five single
readings were taken; these corresponded to the following exhaustions:

  1 / 379,219,500
  1 / 371,057,265
  1 / 250,941,040
  1 / 424,088,232
  1 / 691,082,540

The mean value is 1 / 381,100,000, with a probable error of 10.36 per
cent of the quantity involved. Upon other occasions I have obtained
exhaustions of 1 / 373,134,000 and 1 / 388,200,000. Of course in these
cases a gauge-correction was applied; the highest vacuum that I have
ever obtained irrespective of a gauge-correction was 1 / 190,392,150. In
these cases and in general, potash was employed as the drying material;
I have found it practical, however, to attain vacua as high as 1 /
50,000,000 in the total absence of all such substances. The vapor of
water which collects in bends must be removed from time to time with a
Bunsen burner while the pump is in action.

It is evident that the final condition of the pump is reached when
as much air leaks in per unit of time as can be removed in the same
interval. The total average leakage per ten minutes in the pump used by
me, when at rest, was 0.000211 cubic millimeter at press. 760 mm. Let
us assume that the leakage when the pump is in action is four times
as great as when at rest; then in each ten minutes 0.000844 cubic
millimeter press., 760 mm., would enter; this corresponds in the pump
used by me to an exhaustion of 1 / 124,000,000; if the rate of the pump
is such as to remove one-half of the air present in ten minutes, then
the highest attainable exhaustion would be 1 / 248,000,000. In the same
way it may be shown that if six minutes are required for the removal of
half the air the highest vacuum would be 1 / 413,000,000 nearly, and
rates even higher than this have been observed in my experiments. An
arrangement of the vacuum-bulb whereby the entering drops of mercury
would be exposed to the vacuum in an isolated condition for a somewhat
longer time would doubtless enable the experimenter to obtain
considerably higher vacua than those above given.

_Exhaustion obtained with a plain Sprengel Pump._--I made a series of
experiments with a plain Sprengel pump without stopcocks, and arranged,
as far as possible, like the instrument just described. The leakage per
hour was as follows:

  Duration of the             Leakage per hour in
    experiment.               cubic mm. at press.
                                    760 mm.

  22 hours                          0.04563
   2 days                           0.04520
   2 days                           0.09210
   4 days                           0.06428
                                    -------
            Mean                    0.06180

Using the same reasoning as above we obtain the following table

  Time necessary for removal     Greatest attainable
     of half the air.                exhaustion.

    10 minutes                     1 / 5,000,000
    7.5 minutes                    1 / 7,000,000
    6.6 minutes                    1 / 12,000,000

In point of fact the highest exhaustion I ever obtained with this pump
was 1 / 5,000,000; from which I infer that the leakage during action
is considerably greater than four times that of the pump at rest. The
general run of the experiments tends to show that the leakage of a plain
Sprengel pump, without stopcocks or grease, is, when in action, about 80
times as great as in the form used by me.

_Note on annealing glass tubes._--It is quite necessary to anneal all
those parts of the pump that are to be exposed to heat, otherwise they
soon crack. I found by inclosing the glass in heavy iron tubes and
exposing it for five hours to a temperature somewhat above that of
melting zinc, and then allowing an hour or two for the cooling process,
that the strong polarization figure which it displays in a polariscope
was completely removed, and hence the glass annealed. A common
gas-combustion furnace was used, the bends, etc, being suitably inclosed
in heavy metal and heated over a common ten-fold Bunsen burner. Thus far
no accident has happened to the annealed glass, even when cold drops of
mercury struck in rapid succession on portions heated considerably above
100 deg. C.

I wish, in conclusion, to express my thanks to my assistant, Dr.
Ihlseng, for the labor he has expended in making the large number of
computations necessarily involved in work of this kind.--_Amer. Jour. of
Science._

       *       *       *       *       *




CRYSTALLIZATION TABLE.


The following table, prepared by E. Finot and Arm. Bertrand for the
_Jour. de Ph. et de Chim._, shows the point at which the evaporation of
certain solutions is to be interrupted in order to procure a good crop
of crystals on cooling. The density is according to Baume's scale, the
solution warm:

  Aluminum sulphate       25 | Nickel acetate             30
  Alum (amm. or pot.)     20 |   "    ammon. sulphate     18
  Ammonium acetate        14 |   "    chloride            50
    "      arsenate        5 |   "    sulphate            40
    "      benzoate        5 | Oxalic acid                12
    "      bichromate     28 | Potass. and sod. tartrate  36
    "      bromide        30 | Potassium arsenate         36
    "      chloride       12 |   "       benzoate          2
    "      nitrate        29 |   "       bisulphate       35
    "      oxalate         5 |   "       bromide          40
    "      phosphate      35 |   "       chlorate         22
    "      sulphate       28 |   "       chloride         25
    "      sulphocyanide  18 |   "       chromate         38
    "      tartrate       25 |   "       citrate          36
  Barium ethylsulphate    43 |   "       ferrocyanide     38
    "    formate          32 |   "       iodide           17
    "    hyposulphite     24 |   "       nitrate          28
    "    nitrate          18 |   "       oxalate          30
    "    oxide            12 |   "       permanganate     25
  Bismuth nitrate         70 |   "       sulphate         15
  Boric acid               6 |   "       sulphite         25
  Cadmium bromide         65 |   "       sulphocyanide    35
  Calcium chloride        40 |   "       tartrate         48
    "     ethylsulphate   36 | Soda                       28
    "     lactate          8 | Sodium acetate             22
    "     nitrate         55 |   "    ammon. phosp.       17
  Cobalt chloride         41 |   "    arsenate            36
    "    nitrate          50 |   "    borate              24
    "    sulphate         40 |   "    bromide             55
  Copper acetate           5 |   "    chlorate            43
    "    ammon. sulph.    35 |   "    chromate            45
    "    chloride         45 |   "    citrate             36
    "    nitrate          55 |   "    ethylsulphate       37
    "    sulphate         30 |   "    hyposulphite        24
  Iron-ammon. oxalate     30 |   "    nitrate             40
    " ammon. sulphate     31 |   "    phosphate           20
    " sulphate            31 |   "    pyrophosphate       18
    " tartrate            40 |   "    sulphate            30
  Lead acetate            42 |   "    tungstate           45
    " nitrate             50 | Stroutium bromide          50
  Magnesium chloride      35 |   "       chlorate         65
    "       lactate        6 |   "       chloride         34
    "       nitrate       45 | Tin choride (stannous)     75
    "       sulphate      40 |
  Manganese chloride      47 | Zinc acetate               20
    "       lactate        8 |   "  ammon. chloride       43
    "       sulphate      44 |   "  nitrate               55
  Mercury cyanide         20 |   "  sulphate              45

       *       *       *       *       *




THE PRINCIPLES OF HOP-ANALYSIS.

By Dr. G. O. CECH

[Footnote: 'Zeitschrift fur Analyt. Chemie,' 1881.]


Hop flowers contain a great variety of different substances susceptible
of extraction with ether, alcohol, and water, and distinguishable from
one another by tests of a more or less complex character. The substances
are: Ethereal oil, chlorophyl, hop tannin, phlobaphen, a wax-like
substance, the sulphate, ammoniate, phosphate, citrate and malates of
potash, arabine, a crystallized white and an amorphous brown resin, and
a bitter principle. That the characteristic action of the hops is due to
such of these constituents only as are of an organic nature is easy to
understand; but up to the present we are in ignorance whether it is upon
the oil, the wax, the resin, the tannin, the phlobaphen, or the bitter
principle individually, or upon them all collectively, that the effect
of the hops in brewing depends.

It is the rule to judge the strength and goodness of hops by the amount
of farina--the so-called lupuline; and as this contains the major
portion of the active constituents of the hop, there is no doubt that
approximately the amount of lupuline is a useful quantitative test. But
here we are confronted by the question whether the lupuline is to be
regarded as containing _all_ that is of any value in the hops and the
leaves, the organic principles in which pass undetected under such a
test, as supererogatory for brewers' purposes? Practical experience
negatives any such conclusion. Consequently, we are justified in
assuming that the concurrent development and the presence of the several
organic principles--the oil, the wax, the bitter, the tannin, the
phlobaphen, in the choicer sorts--are subject, within certain limits, to
variations depending on skilled culture and careful drying, and that the
aggregate of these principles has a certain attainable maximum in
the finer sorts, under the most favorable conditions of culture, and
another, lower maximum in less perfectly cultivated and wild sorts. The
difference in the proportion of active organic substance in each sort
must be determined by analysis. There then remains to be discovered
which of the aforesaid substances plays the leading role in brewing, and
also whether the presence of chlorophyl and inorganic salts in the hop
extract influences or alters the results.

That in brewing hops cannot be replaced by lupuline alone, even when the
latter is employed in relatively large quantities is well known, as also
that a considerable portion of the bitter principle of the hop is found
in the floral leaves. Neither can the lupuline be regarded as the only
active beer agent, as both the hop-tannin and the hop-resin serve to
precipitate the albuminous matter, and clarify and preserve the beer.

Both chemists and brewers would gladly welcome some method of testing
hops, which should be expeditious, and afford reliable results in
practical hands. To accomplish this account must be taken of all the
active organic constituents of the hops, which can be extracted either
with ether, alcohol, or water containing soda (for the conversion of the
hop tannin in phlobaphen).[1] It should further be ascertained whether
the chlorophyl percentage in the hop bells, new and old, is or is not
the same in cultivated and in wild hops, and whether the aggregate
percentages of organic and constituent observe the same limits.

[Footnote 1: See C. Etti, in "Dingler's Polytech. Journ.," 1878, p.
354.]

As wild hops nowadays are frequently introduced in brewing, the
proportion of chlorophyl and organic and inorganic constituents in them
should be compared with those of cultivated sorts, taking the best
Bavarian or Bohemian hops as the standard of measurement. The chlorophyl
is of minor importance, as it has little effect on the general results.

By a series of comparative analysis of cultivated and wild hops, in
which I would lay especial stress on parity of conditions in regard
of age and vegetation, the extreme limits of variation of which their
active organic principles are susceptible could be determined.

There is every reason to suppose that the chlorophyl and inorganic
constituents do not differ materially in the most widely different sorts
of hops. The more important differences lie in the proportions of hop
resin and tannin. When this is decided, the proportion of tannin or
phlobaphen in the hop extract or the beer can be determined by analysis
in the ordinary way. But whenever some quick and sure hop test shall
have been found, _appearance and aroma_ will still be most important
factors in any estimate of the value of hops. Here a question arises as
to whether hops from a warm or even a steppe climate, like that of
South Russia, contain the same proportion of ethereal oil--that is, of
aroma--as those from a cooler climate, like Bavaria and Bohemia, or
like certain other fruit species of southern growth, they are early
in maturing, prolific, large in size, and abounding in farina, but
_deficient in aroma_.

The bearings of certain experimental data on this point I reserve for
consideration upon a future occasion.--_The Analyst_.

       *       *       *       *       *




WATER GAS.

A DESCRIPTION OF APPARATUS FOR PRODUCING CHEAP GAS, AND SOME NOTES ON
THE ECONOMICAL EFFECT OF USING SUCH GAS WITH GAS MOTORS, ETC.

[Footnote: Abstract of paper read in Section G. British Association,
York]

By MR. J. EMERSON DOWSON, C.E., of London.


In many countries and for many years past, inventors have sought
some cheap and easy means of decomposing steam in the presence of
incandescent carbon in order to produce a cheap heating gas; and working
with the same object the writer has devised an apparatus which has been
fitted up in the garden of the Industrial Exhibition, and is there
making gas for a 31/2 horse power (nominal) Otto gas engine. The retort or
generator consists of a vertical cylindrical iron casing which incloses
a thick lining of ganister to prevent loss of heat and oxidation of the
metal, and at the bottom of this cylinder is a grate on which a fire is
built up. Under the grate is a closed chamber, and a jet of superheated
steam plays into this and carries with it by induction a continuous
current of air. The pressure of the steam forces the mixture of steam
and air upward through the fire, so that the combustion of the fuel is
maintained while a continuous current of steam is decomposed, and in
this way the working of the generator is constant, and the gas is
produced without fluctuations in quality. The well-known reactions
occur, the steam is decomposed, and the oxygen from the steam and air
combines with the carbon of the fuel to form carbon dioxide (CO_2),
which is reduced to the monoxide (CO) on ascending the fuel column.
In this way the resulting gases form a mixture of hydrogen, carbon,
monoxide, and nitrogen, with a small percentage of carbon dioxide which
usually escapes without reduction. The steam should have a pressure of
11/2 to 2 atmospheres, and is produced and superheated in a zigzag coil
fed with water from a neighboring boiler. The quantity of water required
is very small, being only about 7 pints for each 1,000 cubic feet of
gas, and, except on the first occasion when the apparatus is started,
the coil is heated by some of the gas drawn from the holder, so that
after the gas is lighted under the coil the superheater requires no
attention.

For boiler and furnace work the gas can be used direct from the
generator; but where uniformity of pressure is essential, as for gas
engines, gas burners, etc., the gas should pass into a holder. The
latter somewhat retards the production, but the steam injector causes
gas to be made so rapidly that a holder is easily filled against a back
pressure of 1 in. to 11/2 in. of water, and at this pressure the generator
can pass gas continuously into the holder, while at the same time it is
being drawn off for consumption.

The nature of the fuel required depends on the purpose for which the gas
is used. If for heating boilers, furnaces, etc, coke or any kind of coal
maybe used; but for gas engines or any application of the gas requiring
great cleanliness and freedom from sulphur and ammonia it is best to use
anthracite, as this does not yield condensable vapors, and is very free
from impurities. Good qualities of this fuel contain over 90 per cent of
carbon and so little sulphur that, for some purposes, purification is
not necessary. For gas engines, etc., it is, however, better to pass
the gas through some hydrated oxide of iron to remove the sulphureted
hydrogen. The oxide can be used over and over again after exposure to
the air, and the purifying is thus effected without smell or appreciable
expense. Gas made by this process and with anthracite coal has no tar
and no ammonia, and the small percentage of carbon dioxide present does
not sensibly affect the heating power. A further advantage of this gas
is that it cannot burn with a smoky flame, and there is no deposition of
soot even when the object to be heated is placed over or in the flame,
and this is of importance for the cylinder and valves of a gas engine.

To produce 1,000 cubic feet only 12 lb. of anthracite are required,
allowing 8 to 10 per cent, for impurities and waste; thus a generator
A size, which produces 1,000 cubic feet per hour, needs only 12 lb. in
that time, and this can be added once an hour or at longer intervals. No
skilled labor is necessary, and in practice it is usual to employ a man
who has other work to attend to near the generator, and to pay him a
small addition to his usual wages.

The comparative explosive force of coal gas and the Dowson gas
calculated in the usual way is as 3.4:1, i. e., coal gas has 3.4 times
more energy than the writer's gas. Messrs. Crossley, of Manchester, the
makers of the Otto gas engines, have made several careful trials of this
gas with some of their 31/2 horse power (nominal) engines, and in one
trial they took diagrams every half-hour for nine consecutive days.
These practical trials have shown that without altering the cylinder of
the engine it is possible to admit enough of the Dowson gas to give
the same power as with ordinary coal gas. It has been seen that the
comparative explosive force of the two gases is as 3.4:1, but as it is
well known the combustion of carbon monoxide proceeds at a comparatively
slow rate, and for this reason, and because of the diluents present in
the cylinder which affect the weaker gas more than coal gas, experience
has shown that it is best to allow five volumes of the Dowson gas for
one volume of coal gas, and then the same uniform power is obtained as
with the latter.

This gives very important economical results; for if the cost of the
Dowson gas given in the tables as 41/4d., 3-1/3d., and 23/4d. per 1,000
cubic feet, be multiplied by 5 there will be 1s. 91/4d., 1s. 43/4d., and 1s.
23/4d., or a mean of 1s. 51/2d. for the equivalent of 1,000 cubic feet of
coal gas, which usually costs from 3s. to 4s., and this represents an
actual saving of about 50 to 60 per cent, in working cost. Another
practical consideration is that coal gas requires 224 lb. to 250 lb. of
coal per 1,000 cubic feet of gas, but the writer requires only 12 lb.
per 1,000 cubic feet, and multiplying this by 5 to give the equivalent
of 1,000 cubic feet of coal gas, for engine work, there are 60 lb.
instead of 224 lb. to 250 lb. This is only 24 to 27 per cent, of the
weight of the coal required for coal gas, and in many outlying districts
this will effect an appreciable saving in the cost of transport.


APPENDIX.

   TABLE I.

  _Generator A Size_ (producing 1,000 cubic feet per hour):
    Anthracite to make gas at the rate of 1,000   s.  d.
      cubic feet per hour=l2 lb x 9 working
      hours=l08 lb., or say, 1 cwt. at 20s. a
      ton....................................     1   0
    Allowance for wages of attendant.........     1   0
    Repairs and depreciation of generator,
      gasholder, etc. (5 per cent. on Ll25)=
      per working day........................     0   5
    Interest on capital outlay, ditto........     0   5
                                                 ______

             Total...........................     2  10
                                                  cub. ft.

    Gas produced.............................     9.000
    Less gas used for generating and
       superheating steam.....................    1,000
                                                  _____
             Total effective gas for 2s. 10d.     8,000

  Net cost 41/4 d. per 1,000 cubic feet.

  TABLE II.

  _Generator B Size_ (producing 1,500 cubic feet per hour)
    Anthracite to make gas at the rate of 1,500   s.  d.
      cubic feet per hour=18 lb. x 9 working
      hours=162 lb., or, say, 11/2 cwt. 20s.
      a ton..................................     1    6
    Allowance for wages of attendant.........     1    0
    Repairs and depreciation of generator,
      gasholder, etc. (5 per cent, on L140)
      =per working day.......................     0    51/2
    Interest on capital outlay, ditto........     0    51/2
                                                 ___  ___
             Total...........................     3    5
                                                 cub. ft.
    Gas produced.............................    13,500
    Less gas used for generating and
      superheating steam.....................     1,200
                                                 ______
             Total effective gas for 3s. 5d..    12,300

  Net cost 3 1/3d. per 1,000 cubic feet.

  TABLE III.

  _Generator C Size_ (producing 2,500 cubic feet per hour):
    Anthracite to make gas at the rate of 2,500      s. d.
    cubic feet per hour=30 lb. x 9 working
    hours=270 lb. at 20s. a ton............          2  41/2
    Allowance for wages of attendant.......          1  6
    Repairs and depreciation of generator,
      gasholder, etc. (5 per cent, on L160)=
      per working day......................          0  61/2
    Interest on capital outlay, ditto......          0  61/2
                                                    _______
             Total.........................          4 111/2

                                                     cub. ft.
    Gas produced...........................        22,500
    Less gas used for generating and
      superheating steam...................         1,500
                                                   ______
             Total effective gas for 4s. 111/2d      21,000

  Net cost, say, 23/4 d. per 1,000 cubic feet.

       *       *       *       *       *




ON THE FLUID DENSITY OF CERTAIN METALS.

[Footnote: Abstract of paper read before Section C (Chemical Science),
British Association meeting, York.]

By PROFESSOR W. CHANDLER ROBERTS, F.R.S., and T. WRIGHTSON.


The authors described their experiments on the fluid density of metals
made in continuation of those submitted to Section B at the Swansea
meeting of the Association. Some time since one of the authors gave an
account of the results of experiments made to determine the density of
metallic silver, and of certain alloys of silver and copper when in a
molten state. The method adopted was that devised by Mr. R. Mallet, and
the details were as follows: A conical vessel of best thin Lowmoor plate
(1 millimeter thick), about 16 centimeters in height, and having an
internal volume of about 540 cubic centimeters, was weighed, first
empty, and subsequently when filled with distilled water at a known
temperature. The necessary data were thus afforded for accurately
determining its capacity at the temperature of the air. Molten silver
was then poured into it, the temperature at the time of pouring being
ascertained by the calorimetric method. The precautions, as regards
filling, pointed out by Mr. Mallet, were adopted; and as soon as the
metal was quite cold, the cone with its contents was again weighed.
Experiments were also made on the density of fluid bismuth; and two
distinctive determinations gave the following results:

  10.005 )
         ) mean 10.039.
  10.072 )

The invention of the oncosimeter, which was described by one of the
authors in the "Journal of the Iron and Steel Institute" (No. II.,
1879, p. 418), appeared to afford an opportunity for resuming the
investigation on a new basis, more especially as the delicacy of the
instrument had already been proved by experiments on a considerable
scale for determining the density of fluid cast iron. The following is
the principle on which this instrument acts:

If a spherical ball of any metal be plunged below the surface of a
molten bath of the same or another metal, the cold ball will displace
its own volume of molten metal. If the densities of the cold and molten
metal be the same, there will be equilibrium, and no floating or sinking
effect will be exhibited. If the density of the cold be greater than
that of the molten metal, there will be a sinking effect, and if less a
floating effect when first immersed. As the temperature of the submerged
ball rises, the volume of the displaced liquid will increase or decrease
according as the ball expands or contracts. In order to register these
changes the ball is hung on a spiral spring, and the slightest change in
buoyancy causes an elongation or contraction of this spring which can
be read off on a scale of ounces, and is recorded by a pencil on a
revolving drum. A diagram is thus traced out, the ordinates of which
represent increments of volume, or, in other words, of weight of fluid
displaced--the zero line, or line corresponding to a ball in a liquid of
equal density, being previously traced out by revolving the drum without
attaching the ball of metal itself to the spring, but with all other
auxiliary attachments. By means of a simple adjustment the ball is kept
constantly depressed to the same extent below the surface of the liquid;
and the ordinate of this pencil line, measuring from the line of
equilibrium, thus gives an exact measure of the floating or sinking
effect at every stage of temperature, from the cold solid to the state
when the ball begins to melt.

If the weight and specific gravity of the ball be taken when cold,
there are obtained, with the ordinate on the diagram at the moment of
immersion, sufficient data for determining the density of the fluid
metal; for

W / W1 = D / D1

the volumes being equal. And remembering that

W (weight of liquid) = W1 (weight of ball) + x

(where x is always measured as +_ve_ or -_ve_ floating effect), there is
obtained the equation:

       D1  x ( W1 + x)
  D =  --------------- .
            W1

[TEX: D = \frac{D_1 \times (W_1 +x)}{W_1}]

The results obtained with metallic silver are perhaps the most
interesting, mainly from the fact that the metal melts at a higher
temperature, which was determined with great care by the illustrious
physicist and metallurgist, the late Henri St. Claire Deville, whose
latest experiments led him to fix the melting point at 940 deg. Cent. The
authors of the paper showed that the density of the fluid metal was 9.51
as compared with 10.57, the density of the solid metal. Taking their
results generally, it is found that the change of volume of the
following metals in passing from the solid to the liquid state may be
thus stated:

               Specific       Specific
   Metal.        Gravity,      Gravity,      Percentage of
                 Solid.        Liquid.         Change.

  Bismuth         9.82         10.055     Decrease of volume  2.3
  Copper          8.8           8.217     Increase       "    7.1
  Lead           11.4          10.37          "          "    9.93
  Tin.            7.5           7.025         "          "    6.76
  Zinc            7.2           6.48          "          "   11.10
  Silver         10.57          9.51          "          "   11.20
  Iron            6.95          6.88          "          "    1.02

       *       *       *       *       *




HYDROPHOBIA PREVENTED BY VACCINATION.


M. Pasteur and other French savants have lately been devoting special
attention to hydrophobia. The great authority on germs has, in fact,
definitely announced that he does not intend to rest until he has made
known the exact nature and life-history of this terrible disease, and
discovered a means of preventing or curing it. The most curious result
yet attained in this direction, however, has been announced by Professor
V. Galtier, of the Lyons Veterinary School. This inquirer has found, in
the first place, that if the virus of rabies be injected into the veins
of a sheep, the animal does not subsequently exhibit any symptoms of
hydrophobia. This in itself would be a sufficiently curious result
to justify attention, though its importance, except as confirmatory
testimony, becomes less striking when it is remembered that M. Pasteur
has lately shown that the special _nidus_ of the disease appears to be
the nervous tissue, and particularly the ganglionic centers. But there
is this further curious consequence: sheep who have thus been treated
through the blood, and who are afterwards inoculated in the ordinary
way through the cellular tissue, as if by a bite, are proof against
the disease. It is as though the injection into the veins acted as a
vaccine. Twenty sheep were experimented upon; ten only were treated to
the venous injection, and then all were inoculated through the cellular
tissue. The ten which had been first "vaccinated" continue alive and
well; they have not even shown any adverse symptoms. The other ten have
all died of rabies. It remains to say why M. Galtier experimented
upon sheep, and not upon dogs and cats, which usually communicate the
disease. The incubation of the disease is much more rapid and less
capricious in the sheep than in the dog or in man, and hence M. Galtier
was able to get his results more certainly within a short period. Having
succeeded so far, he is now justified in undertaking the more protracted
series of observations which experiments upon the canine species will
involve; and this he proposes to do. Experiments of this nature are not
without a serious risk, and admiration is almost equally due to the
courage and the intelligence of the experimentalist. But what will the
anti-vaccinator say?--_Pall Mall Gazette_.

       *       *       *       *       *




ON DIPTERA AS SPREADERS OF DISEASE.

By J.W. SLATER.


The two-winged flies, in their behavior to man, stand in a marked
contrast to all the other orders of insects. The Lepidoptera, the
Coleoptera, the Neuroptera, the Hymenoptera no doubt occasion, in some
of their forms at least, much damage to our crops. But none of them are
parasitic in or upon our bodies; none of them persistently intrude into
our dwellings, hover around us in our walks, and harass us with noise
and constant attempts to bite, or at least to crawl upon us. Even the
ants, except in a few tropical districts, rarely act upon the offensive.
The Hemiptera contain one semi-parasitic species which has attained a
"world-wide circulation," and one degraded, purely parasitic group.
But the Diptera, among which the fleas are now generally included as a
degenerated type, comprise more forms personally annoying to man than
all the remaining insect orders put together. These hostile species are,
further, incalculably numerous, and occur in every part of the globe.
Mosquitoes swarm not merely in the swampy forests of the Orinoco or the
Irrawaddy, but in the Tundras of Siberia, en the storm-beaten rocks of
the Loffodens, and are even encountered by voyagers in quest of the
North Pole. The common house fly was probably at one time peculiar to
the Eastern Continent, but it followed the footsteps of the Pilgrim
Fathers, and is now as great a nuisance in the United Slates and the
Dominion as in any part of Europe. It is curious, but distressing, to
note the tendency of evils to become international. We have communicated
to America the house-fly and the Hessian fly, the "cabbage-white,"
the small pox, and the cholera. She, in return, has given us the
_Phylloxera_, a few visitations of yellow fever, the _Blatta gigantea_,
and, climate allowing, may perhaps throw in the Colorado beetle as a
make-weight. In this department, at least, free trade reigns undisputed.
It is a singular thing that no beautiful, useful, or even harmless
species of bird or insect seems capable of acclimatizing itself as do
those characterized by ugliness and noisomeness.

But, returning from this digression, we find in the Diptera the habit of
obtrusion and intrusion, of coming in actual contact with our food and
our persons, combined with another propensity--that of feeding upon
carrion, excrement, blood, pus, and morbid matter of all kinds. This
is a combination far more serious than is generally imagined. If the
fly--which may at any moment settle upon our lips, our eyes, or upon
an abraded part of our skin--were cleanly in its habits, we need feel
little annoyance at its visits. Or if it were the most eager carrion
devourer, but did not, after having dined, think it necessary to
seek our company, we might hold it, as is done too hastily by some
naturalists, a valuable scavenger. I fear, however, that I have already
made too great a concession. So long as very many persons are suffering
from disease--so long as many diseases are capable of being transmitted
from the sick to the healthy--so long must any creature which is in the
habit of flying about, and touching first one person and then another,
be a possible medium of infection and death.

Let us take the following case, by no means imaginary, but a
generalization from occurrences far too frequent: A healthy man, sitting
in his house or walking in the fields, especially in countries where the
insectivorous birds have been shot down, suddenly feels a sharp prick on
his neck or his cheek. Putting his hand to the place he perhaps crushes,
perhaps merely brushes away, a fly which has bitten him so as to draw
blood. The man thinks little of so trifling a hurt, but the next morning
he finds the puncture exceedingly painful. An inflamed pimple forms,
which quickly gets worse, while constitutional symptoms of a feverish
kind come on. In alarm he seeks medical advice. The doctor tells him
that it is a malignant pustule, and takes at once the most active
measures. In spite of all possible skill and care the patient too often
succumbs to the bite of a _mouche charbonneuse_, or carbuncle-fly. But
has any kind of fly the property of producing malignant pustule by
some specific inherent power of its own? Surely not. The antecedent
circumstances are these: A sheep or heifer is attacked with the disease
known in France as _charbon_, in Germany as _milz-brand_, and in England
as _splenic fever_. Its blood on examination would be found plentifully
peopled with bacteria. If a lancet were plunged into the body of the
animal, and were then used to slightly scratch or cut the skin of a man,
he would be inoculated with "charbon." The bite of the fly is precisely
similar in its action. Its rostrum has been smeared with the poisoned
blood, an infinitesimal particle of which is sufficient to inclose
several of the disease "germs," and these are then transferred to the
blood of the next man or animal which the fly happens to bite. The
disease is reproduced as simply and certainly as the spores of some
species of fern give rise to their like if scattered upon soil suitable
for their growth. But flies which do not bite may transfer infection.
Every one must know that if blood be spilt upon the ground a crowd of
flies will settle upon and eagerly absorb it. Animals suffering from
splenic fever in the later stages of the disease sometimes emit bloody
urine. Often they are shot or slaughtered by way of stamping out the
plague, and their carcasses are buried deep in the ground. But some loss
of blood is sure to happen, and this will mostly be left to soak into
the ground. Here again the flies will come, and their feet and mouth
will become charged with the contagion. Such a fly, settling upon
another animal or a man, and selecting--as it will do by preference, if
such exist--a wound, or a place where the skin is broken, will convey
the disease.

Again, M. Pasteur has thoughtfully pointed out that if an animal has
died of splenic fever, and has been carefully buried, the earth-worms
may bring up portions of infectious matter to the surface, so that sheep
grazing, or merely being folded over the spot in question, may take the
plague and die. Hence be wisely counsels that the bodies of such animals
should be buried in sandy or calcareous soils where earth-worms are not
numerous. But it is perfectly legitimate to go a step farther. If such
worm-borings retain the slightest savor of animal matter, flies will
settle upon them and will convey the infectious dust to the most
unexpected places, giving wings to the plague.

Now it is very true that no one has seen a fly feasting upon the blood
of a heifer or sheep dying or just dead of splenic fever, has then
watched it settle upon and bite some person, and has traced the
following stages of the disease. But it is positively known that a
person has been bitten by a fly, and has then exhibited all the symptoms
of charbon, the place of the bite being the primary seat of the
infection. We know also, beyond all doubt, the eagerness with which
flies will suck up blood, and we likewise know the strange persistence
of the disease "germs."

Again, the avidity of flies for purulent matter is not a thing of mere
possibility. In Egypt, where ophthalmia is common, and where the "plague
of flies" seems never to have been removed, it is reported as almost
impossible to keep these insects away from the eyes of the sufferers.
The infection which they thus take up they convey to the eyes of persons
still healthy, and thus the scourge is continually multiplied.

A third case which seems established beyond question is the agency of
mosquitoes in spreading elephantiasis. These so-called sanitary agents
suck from the blood of one person the Filariae, the direct cause of the
disease, and transfer them to another. The manner in which this process
is effected will appear simple enough if we reflect that the mosquito
begins operations by injecting a few drops of fluid into its victim, so
as to dilute the blood and make it easier to be sucked.

So much being established it becomes in the highest degree probable that
every infectious disease may be, and actually is, at times propagated
by the agency of flies. Attention turned to this much neglected quarter
will very probably go far to explain obscure phenomena connected with
the distribution of epidemics and their sudden outbreaks in unexpected
quarters. I have seen it stated that in former outbreaks of pestilence
flies were remarkably numerous, and although mediaeval observations on
Entomology are not to be taken without a grain of salt, the tradition
is suggestive. Perhaps the Diptera have their seasons of unusual
multiplication and emigration. A wave of the common flea appears to have
passed over Maidstone in August, 1880.

We now see the way to some practical conclusions not without importance.
Recognizing a very considerable part of the order of Diptera, or
two-winged flies, as agents in spreading disease, it surely follows
that man should wage war against them in a much more systematic and
consistent manner than at present. The destruction of the common
house-fly by "_papier Moure_," by decoctions of quassia, by various
traps, and by the so-called "catch 'em alive," is tried here and there,
now and then, by some grocer, confectioner, or housewife angry at the
spoliation and defilement caused by these little marauders. But there
is no concerted continuous action--which after all would be neither
difficult nor expensive--and consequently no marked success. Experiments
with a view of finding out new modes of fly-killing are few and far
between.

Every one must occasionally have seen, in autumn, flies as if cemented
to the window-pane, and surrounded with a whitish halo. That in some
seasons numbers of flies thus perish--that the phenomenon is due to a
kind of fungus, the spores of which readily transfer the disease from
one fly to another--we know. But here our knowledge is at fault. We
have not learnt why this fly-epidemic is more rife in some seasons than
others. We are ignorant concerning the methods of multiplying this
fungus at will, and of launching it against our enemies. We cannot tell
whether it is capable of destroying _Stomoxys calcitram_, the blowflies,
gadflies, gnats, mosquitoes, etc. Experiment on these points is rendered
difficult by the circumstance that the fungus is rarely procurable
except in autumn, when some of the species we most need to destroy are
not to be found. Another question is whether the fungus, if largely
multiplied and widely spread, might not prove fatal to other than
Dipterous insects, especially to the Hymenoptera, so many of which,
in their character of plant-fertilizers, are highly useful, or rather
essential to man.

Another fungus, the so-called "green muscardine" (_Isaria destructor_),
has been found so deadly to insects that Prof. Metschnikoff, who is
experimenting upon it, hopes to extirpate the _Phylloxera_, the Colorado
beetle, etc., by its agency.

Coming to better known and still undervalued fly-destroyers, we have
interfered most unwisely with the balance of nature. The substitution of
wire and railings for live fences in so many fields has greatly lessened
the cover both for insectivorous birds and for spiders. The war waged
against the latter in our houses is plainly carried too far. Whatever
may be the case at the Cape, in Australia, or even in Southern Europe,
no British species is venomous enough to cause danger to human beings.
Though cobwebs are not ornamental, save to the eye of the naturalist,
there are parts of our houses where they might be judiciously tolerated:
their scarcity in large towns, even where their prey abounds, is
somewhat remarkable.

But perhaps the most effectual phase of man's war against the flies will
be negative rather than positive, turning not so much on putting to
death the mature individuals as in destroying the matter in which the
larvae are nourished. Or if, from other considerations, we cannot
destroy all organic refuse, we may and should render it unfit for the
multiplication of these vermin. We have, indeed, in most of our large
towns and in their suburbs, abolished cesspools, which are admirable
breeding-places for many kinds of Diptera, and which sometimes presented
one wriggling mass of larvae. We have drained many marshes, ditches,
and unclean pools, rich in decomposing vegetable matter, and have thus
notably checked the propagation of gnats and midges. I know an instance
of a country mansion, situate in one of the best wooded parts of the
home counties, which twenty years ago was almost uninhabitable, owing to
the swarms of gnats which penetrated into every room. But the present
proprietor, being the reverse of pachydermatous, has substituted covered
drains for stagnant ditches, filled up a number of slimy ponds as
neither useful nor ornamental, and now in most seasons the gnats no
longer occasion any annoyance.

But if we have to some extent done away with cesspools and ditches, and
have reaped very distinct benefit by so doing, there is still a grievous
amount of organic matter allowed to putrefy in the very heart of our
cities. The dust bins--a necessary accompaniment of the water-carriage
system of disposing of sewage--are theoretically supposed to be
receptacles mainly for organic refuse, such as coal-ashes, broken
crockery, and at worst the sweepings from the floors. In sober fact
they are largely mixed with the rinds, shells, etc., of fruits and
vegetables, the bones and heads of fish, egg-shells, the sweepings out
of dog-kennels and henhouses, forming thus, in short, a mixture of evil
odor, and well adapted for the breeding-place of not a few Diptera.

The uses to which this "dust" is put when ultimately fetched away are
surprising: without being freed from its organic refuse it is used to
fill up hollows in building-ground, and even for the repair of roads. A
few weeks ago I passed along a road which was being treated according
to the iniquity of Macadam. Over the broken stones had been shot, to
consolidate them, a complex of ashes, cabbage-leaves, egg and periwinkle
shells, straw, potato-parings, a dead kitten (over which a few
carrion-flies were hovering), and other promiscuous nuisances. The road
in question, be it remarked, is highly "respectable," if not actually
fashionable. The houses facing upon it are severely rated, and are
inhabited chiefly by "carriage people." What, then, may not be expected
in lower districts?

Much attention has lately been drawn to the fish trade of London. It has
_not_, however, come out in evidence that the fish retailers, if they
find a quantity of their perishable wares entering into decomposition,
send out late in the evening a messenger, who, watching his opportunity,
throws his burden down in some plot of building land, or over a fence.
When I say that I have seen in one place, close alongside a public
thoroughfare, a heap of about fifty herrings, in most active
putrefaction and buzzing with flies, and some days afterward, in another
place, some twenty soles, it will be understood that such nuisances
can only be occasioned by dealers. To get rid of, or at least greatly
diminish, carrion-flies, house-flies, and the whole class of winged
travelers in disease, it will be, before all things, essential to
abolish such loathsome malpractices. The dustbins must cease being made
the receptacle for putrescent and putrescible matter, the destruction of
which by fire should be insisted upon.

The banishment of slaughter-houses to some truly rural situation, where
the blood and offal could be at once utilized, would be another step
toward depriving flies of their pabulum in the larva state. An equally
important movement would be the substitution of steam or electricity for
horsepower in propelling tram-cars and other passenger carriages, with a
view to minimize the number of horses kept within greater London. Every
large stable is a focus of flies--_Journal of Science_.

       *       *       *       *       *




ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC DISEASES.


At the recent Medical Congress in London, Professor Klebs undertook to
answer the question: "Are there specific organized causes of disease?"

A short historical review of the various opinions of mankind as to the
origin of disease led, the speaker thought, to the presumption that
these causes were specific and organized.

If we now, he said, consider the present state of this question, the
three following points of view present themselves as those from which
the subject may be regarded:

I.--We have to inquire whether the lower organisms, which are found in
the diseased body, may arise there spontaneously; or whether even they
may be regarded as regular constituents of the body.

II.--The morphological relations of these organisms have to be
investigated, and their specific nature in the different morbid
processes has to be determined.

III.--We have to inquire into their biological relations, their
development inside and outside the body, and the conditions under which
they are able to penetrate into the body, and there to set up disease.

_First_.--With regard to the first question, that of the possibility of
spontaneous generation, the speaker gave a decided negative.

_Second and third_.--There is in microscopic organisms a difference of
form corresponding, as a rule, to difference of function. The facts
regarding these various lower forms are briefly reviewed.

"Three groups of hyphomycetae, algae, and schizomycetae, have been
demonstrated to occur in the animal and human organism in infective
diseases. Their significance increases with the increase of their
capacity for development in the animal body. This depends partly upon
their natural or ordinary conditions of life, but partly also, and that
in a very high degree, upon their power of adaptation, which, as Darwin
has shown, is a property of all living things, and causes the production
of new species with new active functions.

"1. The hyphomycetae, on account of their needing an abundant supply
of oxygen, give rise to but few morbid processes, and these run their
course on the surface of the body, and are hence relatively of less
importance. It will be sufficient here to refer to the forms, achorion,
trichophyton, oidium, aspergillus, and the diseases produced by them,
favus, ringworm, and thrush, to show this peculiarity. Nevertheless, we
see that these organisms also (as was proved by the older observations
of Hannover and Zenker) may, under certain circumstances, penetrate into
the interior of the organs. Grawitz, moreover, has recently shown that
their faculty of penetrating into the interior of the organism, and
there undergoing further development, depends on their becoming
accustomed to nitrogenous food.

"2. Only one of the algae, viz., leptothrix, has as yet acquired any
importance as a producer of disease. It gives rise to the formation of
concretions, and that not only in the mouth, but also, as I have shown,
in the salivary ducts and urinary bladder.

"Another alga, the sarcina of Goodsir, may indeed pass through the
organism, without, however, producing in its passage either direct
or indirect disturbances. It seems more worthy of note that many
schizomycetae, and especially the group of bacilli, are evidently nearly
allied to the algae in their morphological and vegetative relations--so
as to be assigned to this class by several authors, and especially by
Cienkowski.

"The schizomycetae furnish, without doubt, by far the most numerous
group of infective diseases. We distinguish within this group two
widely different series of forms, which we will speak of as bacilli and
cocco-bacteria respectively. The former, which was first exhaustively
described by Ferdinand Cohn, and the pathological importance of which,
especially in relation to the splenic disease of cattle, was first shown
by Koch, consist of threads, in the interior of which permanent or
resting-spores are developed. These spores becoming free, are able,
under suitable conditions of life, again to develop into threads. The
whole development of these organisms, and especially the formation
of spores, is completed on the surface of the fluids, and under the
influence of an abundant supply of oxygen.

"The number of affections in which these organisms have been found,
and which may be to a certain extent produced artificially by the
introduction of these organisms into healthy animal bodies, has been
largely increased since the discovery of Koch, that the bacteria of
splenic fever (anthrax) belong to this group. Under this head must be
placed the bacillus malarise (Klebs and Tommassi-Crudeli), the bacillus
typhi abdominalis (Klebs, Ebert), the bacillus typhi exanthematici
(Klebs, observations not yet published), the bacillus of hog-cholera
(Klein), and, finally the bacillus leprosus (Neisser). It would exceed
the time appointed were I to attempt to describe these forms more
minutely. This may, perhaps, be better reserved for discussion and
demonstration.

"Alongside of these general infective diseases produced by bacilli,
local affections also occur, which indicate the presence of these
organisms at the point where disease begins. As an example of these
processes, which probably occur in various organs, I would mention
gastritis bacillaris, of which I shall show you preparations. In this,
we can trace the entrance of the bacilli into the peptic glands, as well
as their further distribution in the walls of the stomach, and in the
vascular system.

"The second group of the pathogenetic schizomycetae I propose to call,
with Billroth, cocco-bacteria, because they consist of collections of
micrococci, which are capable of transforming themselves into short
rods. The former usually form groups united by zoogloea; by prolongation
of the cocci rods are formed, which sprout out, break up by division
into chains, and further lead again to the formation of resting masses
of cocci. I distinguish, further, in this group, two genera--the
microsporina and the monadina; in the former of which the micrococci are
collected into spherical lumps, in the latter into layers. The one class
is developed in artificial cultivation fluid, the other on the surface.
The former requires a medium poor in oxygen, the latter a medium rich in
oxygen, for their development.

"Among the affections produced by microsporina, I reckon especially the
septic processes, and also true diphtheria. On the other hand, to the
processes produced by monadina belong especially a large series of
diseases, which according to their clinical and anatomical features,
may be characterized as inflammatory processes, acute exanthemata, and
infective tumors, or leucocytoses. Of inflammatory processes, those
belong here which do not generally lead to suppuration, such as
rheumatic affections, including the heart, kidney, and liver affections,
which accompany this process, sequelae which, as is well known,
lead more especially to formation of connective tissue, and not to
suppuration. Here, also, belong croupous pneumonia, the allied disease
erysipelas, certain puerperal processes, and finally, parotitis
epidemica, or mumps.

"Among the acute exanthemata, the following may, up to the present time,
be placed in this group; variola-vaccina, scarlatina, and measles.

"The group of infective tumors is represented by tuberculosis, syphilis,
and glanders. Throughout the whole group of cocco-bacteria the
demonstration of organisms in the diseased parts encounters difficulties
which vary considerably in the different kinds."

The speaker concluded by describing the methods (now well known) by
which the powers of the different organisms are tested.

He also referred to Pasteur's, Chauveau's, and Toussaint's recent
experiments.

His conclusion was that the specific communicable diseases are produced
by specific organisms.

       *       *       *       *       *




THE CENTENARY OF THE DISCOVERY OF URANUS.

By W. F. DENNING, F.R.A.S.


The year 1781 was signalized by an astronomical discovery of great
importance, and one which marked the epoch as memorable in the annals
of science. A musician at Bath, William Herschel by name, who had been
constructing some excellent telescopes and making a systematic survey of
the heavens, observed an object on the night of March 13 of that year,
which ultimately proved to be a large planet revolving in an orbit
exterior to that of Saturn. The discovery was as unique as it was
significant. Only five planets, in addition to the Earth, had hitherto
been known; they were observed by the ancients, and by each succeeding
generation, but now a new light burst upon men. The genius of Herschel
had singled out from the host of stars which his telescope revealed
an object the true character of which had evaded human perception for
thousands of years!

[Illustration: FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE STARS AT
ITS DISCOVERY ON MARCH 13, 1781]

The centenary of this remarkable advance in knowledge naturally recalls
to mind the circumstances of the discovery, and makes us inquisitive to
know what new facts have been gleaned of Herschel's planet, now that
a hundred years have passed away, and we are enabled to look back and
review the vast amount of labor which has been accomplished in this wide
and attractive field of astronomical research. We may learn what new
features have been discerned of the new body, and what additional
discoveries in connection with other planets unknown in Herschel's day,
have been effected by aid of the powerful telescopes which have been
devoted to the work. We do not, however, intend dealing with the general
question of planetary discovery, for at a glance we are impressed with
its magnitude. While a century ago five planets only were known, we now
have some two hundred and thirty of these bodies, and the stream of
discovery flows on without abatement through each succeeding year. The
detection of Uranus seems, indeed, to have been the prelude to many
similar discoveries, and to have offered the incentive to greater
diligence and energy on the part of observers in various parts of the
world.

[Illustration: Fig. 2.--ORBITS OF THE URANIAN SATELLITES.]

Many great discoveries have resulted from accident; and the leading
facts attending that of Uranus prove that, in a large measure, the
result was brought about in a similar way. Herschel, as he unwearyingly
swept the heavens night after night, was in quest of sidereal
wonders--such as double stars and nebulae--and he happened to alight
upon the new planet in a purely chance way. He had no expectation of
finding such a remarkable object, and indeed, when he had found it,
wholly mistook its character. There could be no doubt that it was a body
wholly dissimilar to the fixed stars, and it was equally certain that it
could not be a nebula. It had a perceptible disk, for when it had first
come under the critical eye of its discoverer he had noticed immediately
that its appearance differed widely from the multitude of objects which
crossed the field of his telescope. He had been accustomed to see hosts
of stars pass in review, and their aspect was in one respect similar,
namely, they were invariably presented as points of light incapable of
being sensibly magnified, even with the highest powers. True, there was
a great variety of apparent brightness in these objects and a singular
diversity of configuration, but there was no exception to the invariable
feature referred to. The point of light was constant, and no striking
exception was anticipated until one night--March 13, 1781--Herschel
being intently engaged in the examination of some small stars in the
region of Gemini, brought an object under the range of, his telescope,
which his eye at once selected as one of anomalous character.

Applying a higher power, he noticed that it exhibited a planetary disk,
but his instrument failed to define it with sufficient distinctness, and
hence he became doubtful as to its real nature. The object was found to
be in motion, and subsequent observations led him to the assumption that
it must be a comet of rather exceptional type. This appeared to be the
best explanation of the strange body, for history contained many records
of curious comets, some of which were observed as nearly circular
patches of nebulous light, and probably of similar aspect to the object
then visible; and apart from this it must be remembered that the idea of
a large planet exterior to Saturn was a fact of such momentous import
that Herschel, with a due regard to that modesty which accompanies
true genius, refrained from attaching such an interpretation to his
observations. He was content to direct the notice of astronomers to it
as a phenomenon requiring close attention, and suggested that it might
be a comet in consequence of its motion and the faint and somewhat
ill-defined character of its appearance.

From the earliest ages five planets only were known, and the discovery
of another large planet beyond the sphere of Saturn must at once
revolutionize existing ideas as to the range of the solar system, and
immediately take rank as a scientific event of equal interest to the
discovery of the moons of Jupiter or the rings of Saturn, which each in
their day impressed men with new ideas of the celestial mechanism. But
the truth could not long be delayed. The new body being watched and its
orbit rigorously computed from a series of observed positions revealed
its true character, and Herschel was awarded the honor due to the author
of a discovery of such importance. His diligence and pertinacity alone
had enabled him to search out from among the multitude of stars thickly
strewn over the firmament this unknown and well-nigh invisible planet
which, during all the preceding years of the world's history, had eluded
human perception. Men had been all unconscious of its existence as it
had been slowly completing its circuits around the sun, obedient to the
same laws as the other planets of the solar system, and awaiting the
hour when the unfailing eve of Herschel should introduce it as the faint
and far-off planet girding our system within its expansive folds.

As soon as the existence of the new orb was confirmed and the fact
rendered indisputable, the question naturally arose whether it had ever
been seen in former years by the authors of star catalogues, who could
hardly have overlooked an object like this though its planetary nature
had manifestly escaped detection. It was just perceptible to the naked
eye, shining like a star of the sixth magnitude, and ought to have been
distinguished by those who had reviewed the heavens with the purpose
of determining and mapping the positions of the stars. Reference was,
therefore, made to the chief catalogues, when it was found at once that
the planet had been unquestionably observed by Tobias Mayer, Le Monnier,
Bradley, and Flamsteed. It was several times noted by these observers:
by Le Monnier no less than twelve times, and by Flamsteed on six
occasions; and it is remarkable that in every instance its true
character escaped detection. Neither its special appearance nor its
motion attracted attention, so that it was merely catalogued as an
ordinary fixed star. Thus Herschel was not anticipated in his discovery.
It remained for him, in 1781, to note its exceptional aspect, and to
specify it as an object requiring critical investigation. But the early
observations above alluded to served a useful purpose in testing the
accuracy of the computed orbit, for without waiting many years to
compare the theoretical and observed positions, astronomers had in these
old records a reliable series of points through which the previous
course of the planet could be traced.

The calculations showed that its mean distance from the sun was some
1,750,000,000 miles, and that a revolution was completed in about
eighty-four years. It was also found to be a very large planet, greatly
exceeding either Mercury, Venus, the Earth, or Mars, though considerably
inferior to either Jupiter or Saturn.

Here, then, was a discovery of the utmost importance, and one of the
most salient additions to our knowledge which the telescope had ever
achieved. The new planet was now definitely assigned its proper place in
the solar system, and was regarded as of equal significance with the
old planets. True, the new planet of Herschel could not be compared as
regards its visible aspect with the other previously known members of
our system, but it was nevertheless an object of equal weight. Its vast
distance alone rendered it faint. It formed one of the constituent parts
of the solar system, which, though separated by immense intervals of
space, are yet coherent by the far-reaching effects of gravitation.
There is, indeed, a bond of harmony between the series of planetary
orbits, which exhibit a marked degree of regularity in their successive
distances from the sun; and though they are not connected by any visible
links, they are firmly held together by unseen influences, and their
motions are subject to certain laws which have been revealed by
centuries of observation.

The question of suitably naming the new planet soon came to the fore.
Herschel himself proposed to designate it the "Georgium Sidus," in honor
of his patron, George III., just as Galileo had called the satellites
of Jupiter the "Medicean stars," after Cosmo de' Medici. But La Place
proposed that the planet should be named after its discoverer; and thus
it was frequently referred to as "Herschel," and sometimes as "The
Herschelian planet." Astronomers on the continent objected to this
system of personal nomenclature, and argued that the new body should
receive an appellative in accordance with those adopted for the old
planets, which had been selected from the heathen mythology. Several
names were suggested as suitable (on the basis of this principle), and
ultimately the one advanced by Bode received the most favor, and the
planet thereafter was called "Uranus."

The varying positions of the new body as observed on successive nights
were determined by comparisons with a group of six small stars, termed
by Herschel [Greek: alpha, beta, gamma, delta, epsilon] and afterwards
formed into a constellation under the designation of "Britannia," though
it does not appear that this little asterism is acknowledged as one of
our constellations. Its position is about midway between Taurus and
Gemini, and the following are the principal stars computed for 1881.0,
as given by Mr. Marth:

  Star.   Magnitude.  Right Ascension.   Declination.
                      h. m.   s.
  alpha     9.0       5  42  6.06        23 deg. 35'  6.7" N.
  eta       8.7       5  43 17.82        23  26'  7.2  N.
  theta     8.8       5  44  0.99        23  53' 30.8  N.
  epsilon   8.8       5  45 40.68        23  34' 46.8  N.

The stars are therefore merely telescopic, and are confined to a small
area of space, so that the propriety of adopting the group as a distinct
constellation is very questionable. Their positions close to Uranus at
the time of its discovery, and the fact that the planet's motion was
detected by means of comparisons with them, has given to these stars an
historical interest which in future years must often attract the student
to their reobservation. But it would be unwise, as forming a bad
precedent, to accept a group of stars of this inferior type as meriting
to rank among the old constellations, when we have numbers of richer
groups, situated on their confines, which first deserve such a
distinction. However special or unique the circumstances connected with
certain telescopic stars may be, and however necessary it may appear
to signalize them by a specific title, we are inclined to question the
adoption of such means as likely to exercise a wrong influence,
inasmuch as it may hereafter originate further innovations of a similar
character, and ultimate complications will be certain to arise.

Soon after the discovery of Uranus it was suspected that the planet
was encircled, like Saturn, by a luminous ring, but on subsequent
observation this was not confirmed, and no such appendage has ever been
revealed in the more perfected instruments of our own times. Indeed, if
Uranus displays a peculiarity of constitution in any way analogous to
the ring system of Saturn, it must be of the most minute character so as
to have thus evaded telescopic scrutiny during a hundred years.

The discovery soon attracted the notice of royalty, and the reigning
sovereign, George III., anxious to practically express his appreciation
of the valuable labors of Herschel, awarded him a pension of L200 a year
and furnished him with a residence at Slough, near Windsor, and the
means to erect a gigantic telescope with which he might be enabled
to continue his important researches. This instrument consisted of a
reflector on the "Front-view" construction, with a speculum 4 feet in
diameter and of 40 feet focal length. Upon its completion, Herschel
immediately began to observe the region of the new planet with the idea
of discovering any satellites which might belong to it, for analogy
suggested that it was surrounded by a numerous retinue of such bodies.
He was soon successful, for, on the night of January 11, 1787. he saw
two minute objects near the planet, which renewed observations revealed
to be satellites; and he detected two additional ones in 1790, and two
others in 1794, making six in all. But the observations were of extreme
difficulty. The path of the planet frequently passed near minute stars,
and it became hard to distinguish between them and the suspected
satellites. Herschel, however, considered he had obtained conclusive
evidence of the existence of six satellites with sidereal periods
ranging from 5d. 21h. 25m. to 107d. 16h. 39m., and his means of
observation being much superior to those possessed by any of his
contemporaries it was impossible to have corroborative testimony.

The matter was thus allowed to rest until the middle of the present
century, when Lassell, in the pure sky at Malta, endeavored to reobserve
the satellites with a two-foot reflector. This instrument was considered
superior to Herschel's telescope; and the atmosphere at this station
being decidedly more suitable for such delicate observations than
in England, it was removed there for the express purpose of dealing
successfully with objects of extreme difficulty. The results were very
important. Mr. Lassell became convinced that Uranus had only four
satellites, and that if any others existed they remained to be
discovered. Two of these were found to be identical with those seen by
Herschel in 1787, and now called Titania and Oberon. The other two,
Ariel and Umbriel, could not be identified with any of those alleged to
have been previously detected by Herschel, so that the inference was
that they were new bodies, and that the priority of discovery was due to
Mr. Lassell; whence it also followed that the older observations were
erroneous, and that in fact Herschel had been entirely mistaken with
regard to the four satellites he believed he had detected subsequently
to 1787.

In November, 1873, a fine twenty-six-inch object glass, by Alvan Clark,
was mounted at the U. S. Naval Observatory at Washington, and it was
soon employed upon the difficult task of solving the problem as to the
exact periods of the Uranian satellites. This was very satisfactorily
effected, and with distinct and conclusive favor to Mr. Lassell, whose
observations were fully corroborated. Only four satellites could be
distinguished by the American observers, and their periods, as computed
from a valuable series of measures, agreed with those previously derived
at Malta. In Appendix I. to the "Washington Observations" for 1873,
Prof. Newcomb gave a valuable summary of results--the first obtained, be
it noted, with that splendid instrument which soon afterward, in 1877,
revealed the satellites of Mars--which included the elements of the
satellites of Uranus as follows:

  Mean Longitude.

      Satellite.      Epoch 1871.     Radius of        Period of
                    Dec. 31, W.M.T.     Orbit.      Revolution in days.
    I. Ariel........       21.83 deg.       13.78"          2.52038
   II. Umbriel.....        13.52        19.20           4.14418
  III. Titania.....       229.93        31.48           7.70590
   IV. Oberon......       154.83        42.10          13.43327

Speaking of the comparative brightness of the satellites, Prof. Newcomb
says:

"The greater proximity of the inner satellites to the planet makes it
difficult to compare them photometrically with the outer ones, as actual
feebleness of light cannot be distinguished from difficulty of seeing
arising from the proximity of the planet. However, that Umbriel is
intrinsically fainter than Titania is evinced by the fact that, although
the least distance of the latter is somewhat less than the greatest
distance of the former, there is never any difficulty in seeing it in
that position. From their relative aspects in these respective positions
I judge Umbriel to be about half as bright as Titania. Ariel must be
brighter than Umbriel, because I have never seen the latter unless it
was farther from the planet than the former at its maximum distance....
I think I may say with considerable certainty that there is no satellite
within 2' of the planet, and outside of Oberon, having one-third the
brilliancy of the latter, and therefore that none of Sir William
Herschel's supposed outer satellites can have any real existence. The
distances of the four known satellites increase in so regular a way that
it can hardly be supposed that any others exist between them. Of what
may be inside of Ariel it is impossible to speak with certainty, since
in the state of atmosphere which prevails during our winter all the
satellites named disappear at 10" from the planet."

Prof. Newcomb mentions that no systematic search for new satellites
was undertaken because it must have interfered with the fullness and
accuracy of the micrometer measures of the old satellites, which
constituted the main purpose of the observations. Some faint objects
were occasionally glimpsed near the planet, and their relative places
determined, but they were never found to accompany Uranus. The fact,
therefore, that no additional satellites were discovered is not to
be regarded as a strong point in favor of the theory of their
non-existence, because the great power and excellence of the telescope
was expressly directed to the attainment of other ends; and moreover the
season in which the planet came to opposition was distinctly unfavorable
for the prosecution of a rigorous search for new satellites. There
can, however, be no doubt that the analogies of the planetary systems
interior to Uranus plainly suggest that this planet is attended by
several satellites which the power of our greatest telescopes has
hitherto failed to reveal; and that it is in this direction and that of
Neptune we may anticipate further discoveries in future years when the
conditions are more auspicious and the work is entered upon with special
energy, aided by instruments of even greater capacity than those which
have already so far conduced to our knowledge of the heavenly bodies.

Notwithstanding the extreme difficulty with which the Uranian satellites
are observed, the two brighter ones, Titania and Oberon, discovered by
William Herschel in 1787, have been occasionally detected in telescopes
of moderate power, and identified by means of an ephemeris which has
shown that the computed positions approximately agree with those
observed. During the last few years Mr. Marth has published ephemerides
of the satellites of both Saturn and Uranus, and many amateurs have to
acknowledge the valuable aid rendered by these tables, which supply a
ready means of identifying the satellites, and thus act as an incentive
to observers who are induced to pursue such work for the sake of the
interesting comparisons to be made afterward. In one exceptional
instance the two outer satellites of Uranus appear to have been glimpsed
with an object glass of only 43 inches aperture, and the facts are given
in detail in the "Monthly Notices of the R.A.S.," April 1876, pp. 294-6.
The observations were made in January, February, and March, 1876, by
Mr. J.W. Ward, of Belfast; and the positions of the satellites, as he
estimated them on several nights, are compared with those computed, the
two sets presenting tolerably good agreement. Indeed the corroborations
are such as to almost wholly negative any skepticism, though such
extraordinary feats should always be received with caution.

In this particular case the chances of being misled are manifold; even
Herschel himself fell into error in taking minute stars to be satellites
and actually calculating their periods; so that when we remember the
difficulties of the question our doubts are not altogether dispelled.
Extreme acuteness of vision will, in individual instances, lead to
success of abnormal character, and certainly in Mr. Ward's case the
remarkable accordances in the observed and calculated positions appear
to be conclusive evidence that he was not mistaken.

It will be readily inferred that the great distance and consequent
feebleness of Uranus must render any markings upon the disk of the
planet beyond the reach of our best telescopes; and indeed this appears
to have been a matter of common experience. Though the surface has been
often scanned for traces of spots, we seldom find mention that any have
been distinguished. Consequently the period of rotation has yet to be
determined. It is true that an approximate value was assigned by Mr.
T.H. Buffham from observations with a nine-inch reflector in 1870 and
1872. but the materials on which the computation was based were slender
and necessarily somewhat uncertain, so that his period of about twelve
hours stands greatly in need of confirmation. The bright spots and zones
seen on the disk in the years mentioned appear to have entirely eluded
other observers, though they are probably phenomena of permanent
character and within reach of instruments of moderate size. Mr. Buffham
[1] thus describes them:

[Footnote 1: "Monthly Notices K. A. S.," January, 1873.]

"1870, Jan. 25, 11h. to 12h. in clear and tolerably steady air; power
132 showed that the disk was not uniform. With powers 202 and 3.0, two
round, bright spots were perceived, not quite crossing the center but a
little nearer to the eastern side of the planet, the position angle of a
line passing through their centers being about 20 deg. and 200--ellipticity
of Uranus seemed obvious, the major axis lying parallel to the line of
the spots.

"Jan. 27, 10h. to 101/2h.; some fog, and definition not good, but the
appearance of the spots was almost exactly the same as on the 25th."

On March 19 glimpses were obtained of a light streak and two spots.
On April 1, 4, 6, and 8, a luminous zone was seen on the disk, and
in February and March, 1872, when observations were resumed, certain
regions were noted brighter than others, and underwent changes
indicating the rotation of the planet in a similar direction to that
derived from the results obtained in 1870. Mr. Buffham points out that,
if this is admitted, then the plane of the planet's equator is not
coincident with the plane of the orbits of the satellites. Nor need we
be surprised at this departure from the general rule, where such an
anomalous inclination exists. In singular confirmation of this is Mr.
Lassell's observation of 1862, Jan. 29, where he says: "I received an
impression which I am unable to render certain of an equatorial dark
belt, and of an ellipticity of form."

Some observations made in 1872-3 with the great six-foot reflector of
Lord Rosse may here be briefly referred to. A number of measures, both
of position and distance, of Oberon and Titania, were made, [1] and a
few of Umbriel and Ariel, but "the shortness of the time available (40
minutes) each night for the observation of the planet with the six-foot
instrument, the atmospheric disturbance, so often a source of annoyance
in using so large an aperture, and other unfavorable circumstances,
tended to affect the value of the observations, and to make the two
inner satellites rarely within detection."

[Footnote 1: "Monthly Notices R. A. S.," March, 1875.]

On Feb. 10, 1872, Lord Rosse notes that all four satellites were seen on
the same side of the planet. On Jan. 16, 1873, when definition was good,
no traces of any markings were seen. Diameter of Uranus = 5.29". Power
414 was usually employed, though at times the inner satellites could be
more satisfactorily seen with 625.

It may be mentioned as an interesting point that, some fifty years
after the first discovery of Uranus by Herschel, it was accidentally
rediscovered by his son, Sir John Herschel, who recognized it by
its disk, and had no idea as to the identity of the object until an
ephemeris was referred to. Sir John mentions the fact as follows, in a
letter to Admiral Smyth, written in 1830, August 8:

"I have just completed two twenty-foot reflectors, and have got some
interesting observations of the satellites of Uranus. The first sweep
I made with my new mirror I _re-discovered_ this planet by its _disk_,
having blundered upon it by the merest accident for 19 Capricorni."

In commenting upon the centenary of an important scientific discovery we
are naturally attracted to inquire what progress has been made in the
same field during the comparatively short interval of one hundred years
which has elapsed since it occurred. We have called it a short interval,
because it cannot be considered otherwise from an astronomical or
geological point of view, though, as far as human life is concerned,
it can only be regarded as a very lengthy period, including several
generations within its limits.

Since Herschel, in 1781, discovered Uranus, astronomy has progressed
with great rapidity, so that it would be impossible to enumerate in a
brief memoir the many additional discoveries which have resulted from
assiduous observation. A century ago only five planets were known
(excluding the Earth), now we are acquainted with about two hundred and
thirty of these bodies; and one of these, found in 1846, is a large
planet whose orbit lies exterior to that of Uranus. In fact, the state
of astronomical knowledge a century ago has undergone wonderful changes.
It has been rendered far more complete and comprehensive by the
diligence of its adherents and by the unwearying energy with which both
in theory and practice it has been pursued. A zone of small planets has
been discovered between Mars and Jupiter just where the analogies of the
planetary distances indicated the probable existence of a large planet.
The far-off Neptune was revealed in 1846 by a process of analytical
reasoning as unique as it was triumphant, and which proved how well
the theory of planetary perturbations was understood. The planet was
discovered by calculation, its position in the heavens assigned, and the
telescope was then employed merely as the instrument of its detection.
The number of satellites which a century ago numbered only ten has now
reached twenty, and the discovery in 1877 of two moons accompanying Mars
shows that the work is being continued with marked success.

In other departments we also find similar evidence of increasing
knowledge. The periodicity of the sun spots, the existence of systems of
binary stars, meteor showers, and their affinity with cometary orbits
may be mentioned as among the more important, while a host of new
comets, chiefly telescopic, have been detected. Large numbers of nebulae
and double stars have been catalogued, and we have evidence every year
of the activity with which these several branches are being followed up.

In fine, it matters little to what particular department of astronomical
investigation we look for traces of advancement during the past hundred
years, for it is evident throughout them all, and sufficiently proves
that the interest formerly taken in the science has not only been well
sustained but has become more general and popular, and is extending its
attractive features to all classes of the community.

In Herschel's day large telescopes were rare. A man devoting himself to
the study of the heavenly bodies as a means of intellectual recreation
was considered a phenomenon, and indeed that appellation might be
fittingly applied to the few isolated individuals who really occupied
themselves in such work. How different is the case now that the pleasant
ways of science have called so many to her side and so far perfected her
means of research as to make them accessible to all who care to see and
investigate for themselves the unique and wonderful truths so easily
within reach! Large telescopes have become common enough, and there is
no lack of hands and eyes to utilize them, nor of understanding, ever
ready to appreciate, in sincerity and humbleness, those objects which
display in an eminent degree the all-wise conceptions of a great
Creator! It is, therefore, a most gratifying sign to notice this rapid
development of astronomy, and to see year by year the increasing number
of its advocates and the record of many new facts gleaned by vigorous
observation.

The character of recent discoveries distinctly intimates that, in future
years, some departments of the science will become very complicated,
owing to the necessity of dealing with a large number of minute bodies,
for the tendency of modern researches has been to reveal objects which
by their faintness had hitherto eluded detection. And when we consider
that these bodies are rapidly increasing year by year, the idea is
obviously suggested that, inasmuch as their numbers are comparatively
illimitable, and there is likely to be no immediate abatement in the
enthusiasm of observers, difficulties will arise in identifying them
apart and forming them into catalogues with their orbital elements
attached, so that the individual members may be redetected at any time.

In this connection we allude particularly to minor planets, to
telescopic comets, and to meteoric streams, which severally form a very
numerous group of bodies of which the known members are accumulating to
a great extent. As complications arise, some remedies must be applied to
their solution, and one probable effect will be that astronomers will be
induced each one to have a specialty or branch to which his energies are
mainly directed. The science will become so wide in its application and
so intricate in its details that it will become more than ever necessary
for observers to select or single out definite lines of investigation
and pursue them closely, for success is far more likely to attend such
exertions than those which are not devoted to any special end, but
employed rather in a general survey of phenomena.

We have already before us some excellent instances in which individual
energies have been aptly utilized in the prosecution of original work
in some specific branch of astronomy, and we are strongly disposed to
recommend such exclusive labors to those who have the means and the
desire to achieve something useful. Observers who find one subject
monotonous and then take up another for the sake of variation are not
likely to get far advanced in either. In the case of amateurs who use a
telescope merely for amusement, and indiscriminately apply it to nearly
every conspicuous object in the firmament without any particular purpose
other than to satisfy their curiosity, the matter is somewhat different,
and our remarks are not applicable to them. We refer more pointedly
to those who have a regard for the interests of the science and whose
enthusiasm enables them to work habitually and with some pertinacity.

History tells us that the Great Alexander wept when he found he had no
other worlds to conquer, and we fear that some astronomers will lament
that they have little prospect of discovering anything fresh in a sphere
to which our giant telescopes have been so often directed, but this is
founded on a palpable misconception. Certain objects, such as comets for
example, do not require great power, and the revelation of new meteor
showers is entirely a question for the naked eye. In fact, it may be
confidently asserted that observations undertaken with energy and
persistency will, if rightly directed, more than compensate for defects
of instrumental power.

It is true, however, that in certain quarters we must look to large
instruments alone for new discoveries. It would be useless searching for
an ultra-Neptunian planet, or for additional satellites to Uranus or
Neptune, or for the materials to determine the rotation periods of these
planets with a small telescope. Every observer will find objects suited
to the capacity of his instrument, and he may not only employ it
usefully but possibly make a discovery of nearly equal import with that
which rendered the name of Herschel famous a century ago.--_Popular
Science Review_.

       *       *       *       *       *




THE VARYING SUSCEPTIBILITY OF PLANTS AND ANIMALS TO POISONS AND
DISEASES.


Much attention is being devoted to the causes which determine the
aptitude or immunity with animals for maladies. This is in a general
sense called medical geography, as a physician who has prescribed for
patients in various parts of the world, and belonging to different
races--the white, yellow, and black--has been able to note the
diversities in the same disease, and the contradictions in the remedies
employed.

The true social peril, hardly discovered before we became aware how
to conjure it, lies in those legions of animalcules or microbes that
surround us and in the middle of which we live. M. Pasteur has revealed
them to us as the factors in infectious diseases. Claude Bernard
has demonstrated the community which exists between animals and
vegetables--phenomena of movement, of sensibility, of production of
heat, of respiration, of digestion even, for there are the _Drosera_ and
kindred carnivorous plants. Iron cures chlorosis in vegetables as well
as in animals, and chloroform and ether render both insensible. There
resemblances are more striking still between animals. After Baudrimont,
insects are, in presence of alcohols, chloroform, and irrespirable
gases, similarly affected as man. Many maladies, too, are common to
man and several species of animals; and this organic identity is best
illustrated in the relationship between epidemics and epizootias,
cancer, asthma, phthisis, smallpox, rabies, glanders, charbon, etc.,
afflict alike man and many species of animals.

The differences between races are not less remarkable--odor and taste,
for example. According to anthropophagy, negroes are best, and white
people most detestable. Broca remarked, that, in the dissecting room,
the muscles of the negro putrefied less rapidly than those of whites. It
is perhaps to these anatomical differences that the diverse action of
the same poison, in the case of races or species, may be attributed. On
certain rodentia belladonna exercises no influence; morphine for a horse
is a violent stimulant; a snail remains insensible to digitalis; goats
eat tobacco with impunity; and in the Tarentin the inhabitants rear only
black sheep, because a plant abounds which is noxious for white sheep.

The nature of these conditions is a mystery for science. The _Solanae_
tribe of plants furnish a principle which, as its name implies, produces
consolation or forgetfulness, by acting on the tissues of the brain
where resides the organ of thought; now, on the authority of Professor
Bouchardat, these opiates have the less of effect in proportion as the
animals possess the less of intelligence.

To the same anatomical peculiarities must be ascribed the choice that
disease makes in such or such a race. Glanders, for instance, so
virulent with the horse, the ass, and man, produce in the case of the
dog only a local accident; peripneumonia, so contagious among horned
cattle, is more benign in its action on Dutch than other breeds of
stock; the cattle plague that decimates so many farms is communicated by
cattle to each other from the slightest contact, while the closest and
most constant association is necessary to communicate the disease
to sheep, and even when they are affected its action is not severe.
Further, that plague only attacks ruminant animals--oxen, goats, sheep,
zebras, gazelles, etc. Ten years ago this plague broke out in the Jardin
d'Acclimatation; not a ruminant escaped, and also one animal not of that
class, a little tenant nearly related to the pig--the _peccari_.

Now, Dr. Condereau has demonstrated recently that the stomach of the pig
has a rudimentary organization recalling that of the ruminants. Clearly,
the stomach of the peccari, and perhaps that of the pig, present a
favorable medium for the parasitical microbe peculiar to the rinderpest.
In the potato disease, again, all the varieties are not affected with
the same degree of violence; it is more marked in its action on the
round yellows than the reds, and on the latter rather than the pink. But
the symptoms even of the same malady differ, the parasite's attacks on
the tissues being dissimilar. Oak galls are produced from the prickings
of insects; now around the same larva often four varieties of galls are
recognized. In the case of consumption in cattle, the disease marches
slowly; in that of pigs it takes the galloping form, as with man.

Each people or nation has its peculiar pathology and also its peculiar
cures. A negro can take a dose of tartar ten times more excessive than a
white; the same dose of brandy given to a black, a yellow, and a white,
will not produce on the three men either drunkenness at the same moment,
or intoxication at all. Mulattoes can sustain more drastic aperients
than other races; the negro does not suffer from yellow fever, but he
readily falls to phthisis; he will catch the cholera more quickly than a
white. Human races, where they may catch the same intermittent fever at
the identical moment and in the same swamp, will not the less display
different types of fever. Dr. Crevaux has shown that a certain insect
with the North American Indian is not the same as with the negro or the
maroon, and both differ from that peculiar to Europeans.

M. Pasteur's beautiful experiments have conclusively demonstrated that
fowls do not catch the _charbon_; now the vital warmth of birds is from
seven to nine degrees higher than in the case of mammiferous animals;
he imagined that if the fowl was cooled down by baths to the lower
temperature, it would be liable equally to become affected; he tried,
and the result proved he was correct.

The absence, then, of a certain temperature would be the reason why
birds are exempt. The microbes are the agents of infectious disease;
when these swarm in the blood of an individual they seem to leave there
something pernicious for parasites resembling themselves, or to bring
away with them something necessary to the life of their successors. A
glass of sugar and water, where leaven has already fermented and yielded
alcohol, is incapable of producing a second crop of leaven; similarly
the blood of an individual, once contaminated, becomes uninhabitable
afterward for like microbes. The individual has acquired immunity. Such
is the principle of vaccination.--_Paris Correspondent of the Kansas
City Review_.

       *       *       *       *       *




KIND TREATMENT OF HORSES.


It has been observed by experienced horse trainers that naturally
vicious horses are rare, and that among those that are properly trained
and kindly treated when colts they are the exception.

It is superfluous to say that a gentle and docile horse is always the
more valuable, other qualities being equal, and it is almost obvious
that gentle treatment tends to develop this admirable quality in the
horse as well as in the human species, while harsh treatment has the
contrary tendency. Horses have been trained so as to be entirely
governed by the words of his driver, and they will obey and perform
their simple but important duties with as much alacrity as the child
obeys the direction of the parent.

It is true that all horses are not equally intelligent and tractable,
but it is probable that there is less difference among them in this
regard than there is among his human masters, since there are many
incitements and ambitions among men that do not affect animals.

The horse learns to know and to have confidence in a gentle driver, and
soon discovers how to secure for himself that which he desires, and
to understand his surroundings and his duties. The tone, volume, and
inflection of his master's voice indicate much, perhaps more than the
words that are spoken. Soothing tones rather than words calm him if
excited by fear or anger, and angry and excited tones tend to excite or
anger him. In short, bad masters make bad horses.

       *       *       *       *       *

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