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+The Project Gutenberg EBook of Scientific American Supplement, No. 460,
+October 25, 1884, by Various
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Scientific American Supplement, No. 460, October 25, 1884
+
+Author: Various
+
+Release Date: March 28, 2004 [EBook #11734]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK  SCIENTIFIC AMERICAN 460 ***
+
+
+
+
+Produced by Don Kretz, Juliet Sutherland, Charles Franks and the DP Team
+
+
+
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 460
+
+
+
+
+NEW YORK, OCTOBER 25, 1884
+
+Scientific American Supplement. Vol. XVIII, No. 460.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+       *       *       *       *       *
+
+
+TABLE OF CONTENTS.
+
+I.    CHEMISTRY. ETC.--Wolpert's Method of Estimating the
+      Amount of Carbonic Acid in the Air.--7 Figures.
+
+      Japanese Camphor.--Its preparation, experiments, and analysis
+      of the camphor oil.--By H. OISHI.
+
+II.   ENGINEERING AND MECHANICS.--Links in the History of the
+      Locomotive.--With two engravings of the Rocket.
+
+      The Flow of Water through Turbines and Screw Propellers.--By
+      ARTHUR RIGG.--Experimental researches.--Impact on level
+      plate.--Impact and reaction in confined channels.--4 figures.
+
+      Improved Textile Machinery.--The Textile Exhibition at
+      Islington.--5 figures.
+
+      Endless Rope Haulage.--2 figures.
+
+III.  TECHNOLOGY.--A Reliable Water Filter.--With engraving.
+
+      Simple Devices for Distilling Water.--4 figures.
+
+      Improved Fire Damp Detecter.--With full description and engraving.
+
+      Camera Attachment for Paper Photo Negatives.--2 figures.
+
+      Instantaneous Photo Shutter.--1 figure.
+
+      Sulphurous Acid.--Easy method of preparation for photographic
+      purposes.
+
+IV.   PHYSICS. ELECTRICITY, ETC.--Steps toward a Kinetic
+      Theory of Matter.--Address by Sir Wm. THOMSON at the Montreal
+      meeting of the British Association.
+
+      Application of Electricity to Tramways.--By M. HOLROYD
+      SMITH.--7 figures.
+
+      The Sunshine Recorder.--1 figure.
+
+V.    ARCHITECTURE AND ART.--The National Monument at Rome.--With
+      full page engraving.
+
+      On the Evolution of Forms of Art.--From a paper by Prof.
+      JACOBSTHAL.--Plant Forms the archetypes of cashmere
+      patterns.--Ornamental representations of plants of two
+      kinds.--Architectural forms of different ages.--20 figures.
+
+VI.   NATURAL HISTORY.--The Latest Knowledge about Gapes.--How
+      to keep poultry free from them.
+
+      The Voyage of the Vettor Pisani.--Shark fishing In the Gulf
+      of Panama.--Capture of Rhinodon typicus, the largest fish in
+      existence.
+
+VII.  HORTICULTURE, ETC.--The Proper Time for Cutting Timber.
+
+      Raising Ferns from Spores.--1 figure.
+
+      The Life History of Vaucheria.--Growth of alga vaucheria
+      under the microscope.--4 figures.
+
+VIII. MISCELLANEOUS.--Fires in London and New York.
+
+      The Greely Arctic Expedition.--With engraving.
+
+      The Nile Expedition.--1 figure.
+
+       *       *       *       *       *
+
+
+
+
+LINKS IN THE HISTORY OF THE LOCOMOTIVE.
+
+
+It is, perhaps, more difficult to write accurate history than anything
+else, and this is true not only of nations, kings, politicians, or wars,
+but of events and things witnessed or called into existence in every-day
+life. In _The Engineer_ for September 17, 1880, we did our best to place a
+true statement of the facts concerning the Rocket before our readers. In
+many respects this was the most remarkable steam engine ever built, and
+about it there ought to be no difficulty, one would imagine, in arriving at
+the truth. It was for a considerable period the cynosure of all eyes.
+Engineers all over the world were interested in its performance. Drawings
+were made of it; accounts were written of it, descriptions of it abounded.
+Little more than half a century has elapsed since it startled the world by
+its performance at Rainhill, and yet it is not too much to say that the
+truth--the whole truth, that is to say--can never now be written. We are,
+however, able to put some facts before our readers now which have never
+before been published, which are sufficiently startling, and while
+supplying a missing link in the history of the locomotive, go far to show
+that much that has hitherto been held to be true is not true at all.
+
+When the Liverpool and Manchester Railway was opened on the 15th of
+September, 1830, among those present was James Nasmyth, subsequently the
+inventor of the steam hammer. Mr. Nasmyth was a good freehand draughtsman,
+and he sketched the Rocket as it stood on the line. The sketch is still in
+existence. Mr. Nasmyth has placed this sketch at our disposal, thus earning
+the gratitude of our readers, and we have reproduced as nearly as possible,
+but to a somewhat enlarged scale, this invaluable link in the history of
+the locomotive. Mr. Nasmyth writes concerning it, July 26, 1884: "This
+slight and hasty sketch of the Rocket was made the day before the opening
+of the Manchester and Liverpool Railway, September 12, 1830. I availed
+myself of the opportunity of a short pause in the experimental runs with
+the Rocket, of three or four miles between Liverpool and Rainhill, George
+Stephenson acting as engine driver and his son Robert as stoker. The
+limited time I had for making my sketch prevented me from making a more
+elaborate one, but such as it is, all the important and characteristic
+details are given; but the pencil lines, after the lapse of fifty-four
+years, have become somewhat indistinct." The pencil drawing, more than
+fifty years old, has become so faint that its reproduction has become a
+difficult task. Enough remains, however, to show very clearly what manner
+of engine this Rocket was. For the sake of comparison we reproduce an
+engraving of the Rocket of 1829. A glance will show that an astonishing
+transformation had taken place in the eleven months which had elapsed
+between the Rainhill trials and the opening of the Liverpool and Manchester
+Railway. We may indicate a few of the alterations. In 1829 the cylinders
+were set at a steep angle; in 1830 they were nearly horizontal. In 1829 the
+driving wheels were of wood; in 1830 they were of cast iron. In 1829 there
+was no smoke-box proper, and a towering chimney; in 1830 there was a
+smoke-box and a comparatively short chimney. In 1829 a cask and a truck
+constituted the tender; in 1830 there was a neatly designed tender, not
+very different in style from that still in use on the Great Western broad
+gauge. All these things may perhaps be termed concomitants, or changes in
+detail. But there is a radical difference yet to be considered. In 1829 the
+fire-box was a kind of separate chamber tacked on to the back of the barrel
+of the boiler, and communicating with it by three tubes; one on each side
+united the water spaces, and one at the top the steam spaces. In 1830 all
+this had disappeared, and we find in Mr. Nasmyth's sketch a regular
+fire-box, such as is used to this moment. In one word, the Rocket of 1829
+is different from the Rocket of 1830 in almost every conceivable respect;
+and we are driven perforce to the conclusion that the Rocket of 1829
+_never worked at all on the Liverpool and Manchester Railway; the engine of
+1830 was an entirely new engine_. We see no possible way of escaping from
+this conclusion. The most that can be said against it is that the engine
+underwent many alterations. The alterations must, however, have been so
+numerous that they were tantamount to the construction of a new engine. It
+is difficult, indeed, to see what part of the old engine could exist in the
+new one; some plates of the boiler shell might, perhaps, have been
+retained, but we doubt it. It may, perhaps, disturb some hitherto well
+rooted beliefs to say so, but it seems to us indisputable that the Rocket
+of 1829 and 1830 were totally different engines.
+
+[Illustration: FIG. 1. THE ROCKET, 1829. THE ROCKET, 1830.]
+
+Our engraving, Fig. 1, is copied from a drawing made by Mr. Phipps,
+M.I.C.E., who was employed by Messrs. Stephenson to compile a drawing of
+the Rocket from such drawings and documents as could be found. This
+gentleman had made the original drawings of the Rocket of 1829, under
+Messrs. G. & R. Stephenson's direction. Mr. Phipps is quite silent about
+the history of the engine during the eleven months between the Rainhill
+trials and the opening of the railway. In this respect he is like every one
+else. This period is a perfect blank. It is assumed that from Rainhill the
+engine went back to Messrs. Stephenson's works; but there is nothing on the
+subject in print, so far as we are aware. Mr. G.R. Stephenson lent us in
+1880 a working model of the Rocket. An engraving of this will be found in
+_The Engineer_ for September 17, 1880. The difference between it and the
+engraving below, prepared from Mr. Phipps' drawing, is, it will be seen,
+very small--one of proportions more than anything else. Mr. Stephenson says
+of his model: "I can say that it is a very fair representation of what the
+engine was before she was altered." Hitherto it has always been taken for
+granted that the alteration consisted mainly in reducing the angle at which
+the cylinders were set. The Nasmyth drawing alters the whole aspect of the
+question, and we are now left to speculate as to what became of the
+original Rocket. We are told that after "it" left the railway it was
+employed by Lord Dundonald to supply steam to a rotary engine; then it
+propelled a steamboat; next it drove small machinery in a shop in
+Manchester; then it was employed in a brickyard; eventually it was
+purchased as a curiosity by Mr. Thomson, of Kirkhouse, near Carlisle, who
+sent it to Messrs. Stephenson to take care of. With them it remained for
+years. Then Messrs. Stephenson put it into something like its original
+shape, and it went to South Kensington Museum, where "it" is now. The
+question is, What engine is this? Was it the Rocket of 1829 or the Rocket
+of 1830, or neither? It could not be the last, as will be understood from
+Mr. Nasmyth's drawing; if we bear in mind that the so-called fire-box on
+the South Kensington engine is only a sham made of thin sheet iron without
+water space, while the fire-box shown in Mr. Nasmyth's engine is an
+integral part of the whole, which could not have been cut off. That is to
+say, Messrs. Stephenson, in getting the engine put in order for the Patent
+Office Museum, certainly did not cut off the fire-box shown in Mr.
+Nasmyth's sketch, and replace it with the sham box now on the boiler. If
+our readers will turn to our impression for the 30th of June, 1876, they
+will find a very accurate engraving of the South Kensington engine, which
+they can compare with Mr. Nasmyth's sketch, and not fail to perceive that
+the differences are radical.
+
+In "Wood on Railroads," second edition, 1832, page 377, we are told that
+"after those experiments"--the Rainhill trials--"were concluded, the
+Novelty underwent considerable alterations;" and on page 399, "Mr.
+Stephenson had also improved the working of the Rocket engine, and by
+applying the steam more powerfully in the chimney to increase the draught,
+was enabled to raise a much greater quantity of steam than before." Nothing
+is said as to where the new experiments took place, nor their precise date.
+But it seems that the Meteor and the Arrow--Stephenson engines--were tried
+at the same time; and this is really the only hint Wood gives as to what
+was done to the Rocket between the 6th of October, 1829, and the 15th of
+September, 1830.
+
+There are men still alive who no doubt could clear up the question at
+issue, and it is much to be hoped that they will do so. As the matter now
+stands, it will be seen that we do not so much question that the Rocket in
+South Kensington Museum is, in part perhaps, the original Rocket of
+Rainhill celebrity, as that it ever ran in regular service on the Liverpool
+and Manchester Railway. Yet, if not, then we may ask, what became of the
+Rocket of 1830? It is not at all improbable that the first Rocket was cast
+on one side, until it was bought by Lord Dundonald, and that its history is
+set out with fair accuracy above. But the Rocket of the Manchester and
+Liverpool Railway is hardly less worthy of attention than its immediate
+predecessor, and concerning it information is needed. Any scrap of
+information, however apparently trifling, that can be thrown on this
+subject by our readers will be highly valued, and given an appropriate
+place in our pages.--_The Engineer_.
+
+       *       *       *       *       *
+
+The largest grain elevator in the world, says the _Nashville American_, is
+that just constructed at Newport News under the auspices of the Chesapeake
+& Ohio Railway Co. It is 90 ft. wide, 386 ft. long, and about 164 ft. high,
+with engine and boiler rooms 40 × 100 ft. and 40 ft. high. In its
+construction there were used about 3,000 piles, 100,000 ft. of white-oak
+timber, 82,000 cu. ft. of stone, 800,000 brick, 6,000,000 ft. of pine and
+spruce lumber, 4,500 kegs of nails, 6 large boilers, 2 large engines, 200
+tons of machinery, 20 large hopper-scales, and 17,200 ft. of rubber belts,
+from 8 to 48 in. wide and 50 to 1,700 ft. long; in addition, there were
+8,000 elevator buckets, and other material. The storage capacity is
+1,600,000 bushels, with a receiving capacity of 30,000, and a shipping
+capacity of 20,000 bushels per hour.
+
+       *       *       *       *       *
+
+
+
+
+THE FLOW OF WATER THROUGH TURBINES AND SCREW PROPELLERS.
+
+[Footnote: Paper read before the British Association at Montreal.]
+
+By Mr. ARTHUR RIGG, C.E.
+
+
+Literature relating to turbines probably stands unrivaled among all that
+concerns questions of hydraulic engineering, not so much in its voluminous
+character as in the extent to which purely theoretical writers have ignored
+facts, or practical writers have relied upon empirical rules rather than
+upon any sound theory. In relation to this view, it may suffice to note
+that theoretical deductions have frequently been based upon a
+generalization that "streams of water must enter the buckets of a turbine
+without shock, and leave them without velocity." Both these assumed
+conditions are misleading, and it is now well known that in every good
+turbine both are carefully disobeyed. So-called practical writers, as a
+rule, fail to give much useful information, and their task seems rather in
+praise of one description of turbine above another. But generally, it is of
+no consequence whatever how a stream of water may be led through the
+buckets of any form of turbine, so long as its velocity gradually becomes
+reduced to the smallest amount that will carry it freely clear of the
+machine.
+
+The character of theoretical information imparted by some _Chicago Journal
+of Commerce_, dated 20th February, 1884. There we are informed that "the
+height of the fall is one of the most important considerations, as the same
+stream of water will furnish five times the horse power at ten ft. that it
+will at five ft. fall." By general consent twice two are four, but it has
+been reserved for this imaginative writer to make the useful discovery that
+sometimes twice two are ten. Not until after the translation of Captain
+Morris' work on turbines by Mr. E. Morris in 1844, was attention in America
+directed to the advantages which these motors possessed over the gravity
+wheels then in use. A duty of 75 per cent. was then obtained, and a further
+study of the subject by a most acute and practical engineer, Mr. Boyden,
+led to various improvements upon Mr. Fauneyron's model, by which his
+experiments indicated the high duty of 88 per cent. The most conspicuous
+addition made by Mr. Boyden was the diffuser. The ingenious contrivance had
+the effect of transforming part of whatever velocity remained in the stream
+after passing out of a turbine into an atmospheric pressure, by which the
+corresponding lost head became effective, and added about 3 per cent. to
+the duty obtained. It may be worth noticing that, by an accidental
+application of these principles to some inward flow turbines, there is
+obtained most, if not all, of whatever advantage they are supposed to
+possess, but oddly enough this genuine advantage is never mentioned by any
+of the writers who are interested in their introduction or sale. The
+well-known experiments of Mr. James B. Francis in 1857, and his elaborate
+report, gave to hydraulic engineers a vast store of useful data, and since
+that period much progress has been made in the construction of turbines,
+and literature on the subject has become very complete.
+
+In the limits of a short paper it is impossible to do justice to more than
+one aspect of the considerations relating to turbines, and it is now
+proposed to bring before the Mechanical Section of the British Association
+some conclusions drawn from the behavior of jets of water discharged under
+pressure, more particularly in the hope that, as water power is extremely
+abundant in Canada, any remarks relating to the subject may not fail to
+prove interesting.
+
+Between the action of turbines and that of screw propellers exists an exact
+parallelism, although in one case water imparts motion to the buckets of a
+turbine, while in the other case blades of a screw give spiral movement to
+a column of water driven aft from the vessel it propels forward. Turbines
+have been driven sometimes by impact alone, sometimes by reaction above,
+though generally by a combination of impact and reaction, and it is by the
+last named system that the best results are now known to be obtained.
+
+The ordinary paddles of a steamer impel a mass of water horizontally
+backward by impact alone, but screw propellers use reaction somewhat
+disguised, and only to a limited extent. The full use and advantages of
+reaction for screw propellers were not generally known until after the
+publication of papers by the present writer in the "Proceedings" of the
+Institution of Naval Architects for 1867 and 1868, and more fully in the
+"Transactions" of the Society of Engineers for 1868. Since that time, by
+the author of these investigations then described, by the English
+Admiralty, and by private firms, further experiments have been carried out,
+some on a considerable scale, and all corroborative of the results
+published in 1868. But nothing further has been done in utilizing these
+discoveries until the recent exigencies of modern naval warfare have led
+foreign nations to place a high value upon speed. Some makers of torpedo
+boats have thus been induced to slacken the trammels of an older theory and
+to apply a somewhat incomplete form of the author's reaction propeller for
+gaining some portion of the notable performance of these hornets of the
+deep. Just as in turbines a combination of impact and reaction produces the
+maximum practical result, so in screw propellers does a corresponding gain
+accompany the same construction.
+
+[Illustration: FIG. 1.]
+
+[Illustration: FIG. 2.]
+
+_Turbines_.--While studying those effects produced by jets of water
+impinging upon plain or concave surfaces corresponding to buckets of
+turbines, it simplifies matters to separate these results due to impact
+from others due to reaction. And it will be well at the outset to draw a
+distinction between the nature of these two pressures, and to remind
+ourselves of the laws which lie at the root and govern the whole question
+under present consideration. Water obeys the laws of gravity, exactly like
+every other body; and the velocity with which any quantity may be falling
+is an expression of the full amount of work it contains. By a sufficiently
+accurate practical rule this velocity is eight times the square root of the
+head or vertical column measured in feet. Velocity per second = 8 sqrt
+(head in feet), therefore, for a head of 100 ft. as an example, V = 8 sqrt
+(100) = 80 ft. per second. The graphic method of showing velocities or
+pressures has many advantages, and is used in all the following diagrams.
+Beginning with purely theoretical considerations, we must first recollect
+that there is no such thing as absolute motion. All movements are relative
+to something else, and what we have to do with a stream of water in a
+turbine is to reduce its velocity relatively to the earth, quite a
+different thing to its velocity in relation to the turbine; for while the
+one may be zero, the other may be anything we please. ABCD in Fig. 1
+represents a parallelogram of velocities, wherein AC gives the direction of
+a jet of water starting at A, and arriving at C at the end of one second or
+any other division of time. At a scale of 1/40 in. to 1 ft., AC represents
+80 ft., the fall due to 100 ft. head, or at a scale of 1 in. to 1 ft., AC
+gives 2 ft., or the distance traveled by the same stream in 1/40 of a
+second. The velocity AC may be resolved into two others, namely, AB and AD,
+or BC, which are found to be 69.28 ft. and 40 ft. respectively, when the
+angle BAC--generally called _x_ in treatises on turbines--is 30 deg. If,
+however, AC is taken at 2 ft., then A B will be found = 20.78 in., and BC =
+12 in. for a time of 1/40 or 0.025 of a second. Supposing now a flat plate,
+BC = 12 in. wide move from DA to CB during 0.025 second, it will be readily
+seen that a drop of water starting from A will have arrived at C in 0.025
+second, having been flowing along the surface BC from B to C without either
+friction or loss of velocity. If now, instead of a straight plate, BC, we
+substitute one having a concave surface, such as BK in Fig. 2, it will be
+found necessary to move it from A to L in 0.025 second, in order to allow a
+stream to arrive at C, that is K, without, in transit, friction or loss of
+velocity. This concave surface may represent one bucket of a turbine.
+Supposing now a resistance to be applied to that it can only move from A to
+B instead of to L. Then, as we have already resolved the velocity A C into
+AB and BC, so far as the former (AB) is concerned, no alteration occurs
+whether BK be straight or curved. But the other portion, BC, pressing
+vertically against the concave surface, BK, becomes gradually diminished in
+its velocity in relation to the earth, and produces and effect known as
+"reaction." A combined operation of impact and reaction occurs by further
+diminishing the distance which the bucket is allowed to travel, as, for
+examples, to EF. Here the jet is impelled against the lower edge of the
+bucket, B, and gives a pressure by its impact; then following the curve BK,
+with a diminishing velocity, it is finally discharged at K, retaining only
+sufficient movement to carry the water clear out of the machine. Thus far
+we have considered the movement of jets and buckets along AB as straight
+lines, but this can only occur, so far as buckets are concerned, when their
+radius in infinite. In practice these latter movements are always curves of
+more or less complicated form, which effect a considerable modification in
+the forms of buckets, etc., but not in the general principles, and it is
+the duty of the designer of any form of turbine to give this consideration
+its due importance. Having thus cleared away any ambiguity from the terms
+"impact," and "reaction," and shown how they can act independently or
+together, we shall be able to follow the course and behavior of streams in
+a turbine, and by treating their effects as arising from two separate
+causes, we shall be able to regard the problem without that inevitable
+confusion which arises when they are considered as acting conjointly.
+Turbines, though driven by vast volumes of water, are in reality impelled
+by countless isolated jets, or streams, all acting together, and a clear
+understanding of the behavior of any one of these facilitates and concludes
+a solution of the whole problem.
+
+_Experimental researches_.--All experiments referred to in this paper were
+made by jets of water under an actual vertical head of 45 ft., but as the
+supply came through a considerable length of ½ in. bore lead piping, and
+many bends, a large and constant loss occurred through friction and bends,
+so that the actual working head was only known by measuring the velocity of
+discharge. This was easily done by allowing all the water to flow into a
+tank of known capacity. The stop cock had a clear circular passage through
+it, and two different jets were used. One oblong measured 0.5 in. by 0.15
+in., giving an area of 0.075 square inch. The other jet was circular, and
+just so much larger than ¼ in. to be 0.05 of a square inch area, and the
+stream flowed with a velocity of 40 ft. per second, corresponding to a head
+of 25 ft. Either nozzle could be attached to the same universal joint, and
+directed at any desired inclination upon the horizontal surface of a
+special well-adjusted compound weighing machine, or into various bent tubes
+and other attachments, so that all pressures, whether vertical or
+horizontal, could be accurately ascertained and reduced to the unit, which
+was the quarter of an ounce. The vertical component _p_ of any pressure P
+may be ascertained by the formula--
+
+    _p_ = P sin alpha,
+
+where alpha is the angle made by a jet against a surface; and in order to
+test the accuracy of the simple machinery employed for these researches,
+the oblong jet which gave 71 unit when impinging vertically upon a circular
+plate, was directed at 60 deg. and 45 deg. thereon, with results shown in
+Table I., and these, it will be observed, are sufficiently close to theory
+to warrant reliance being placed on data obtained from the simple weighing
+machinery used in the experiment.
+
+                 _Table I.--Impact on Level Plate._
+--------------+--------------------+----------+----------+----------
+              | Inclination of jet |          |          |
+  Distance.   | to the horizonal.  |  90 deg. |  60 deg. |  45 deg.
+--------------+--------------------+----------+----------+----------
+              |                    | Pressure | Pressure | Pressure
+              |                    |          |          |
+            / |  Experiment    \   |        / |   61.00  |   49.00
+ 1½ in.    <  |                 >  | 71.00 <  |          |
+            \ |  Theory        /   |        \ |   61.48  |   50.10
+              |                    |          |          |
+              |                    |          |          |
+            / |  Experiment    \   |        / |   55.00  |   45.00
+ 1 in.     <  |                 >  | 63.00 <  |          |
+            \ |  Theory        /   |        \ |   54.00  |   45.00
+              |                    |          |          |
+--------------+--------------------+----------+----------+----------
+             In each case the unit of pressure is ¼ oz.
+
+In the first trial there was a distance of 1½ in. between the jet and point
+of its contact with the plate, while in the second trial this space was
+diminished to ½ in. It will be noticed that as this distance increases we
+have augmented pressures, and these are not due, as might be supposed, to
+increase of head, which is practically nothing, but they are due to the
+recoil of a portion of the stream, which occurs increasingly as it becomes
+more and more broken up. These alterations in pressure can only be
+eliminated when care is taken to measure that only due to impact, without
+at the same time adding the effect of an imperfect reaction. Any stream
+that can run off at all points from a smooth surface gives the minimum of
+pressure thereon, for then the least resistance is offered to the
+destruction of the vertical element of its velocity, but this freedom
+becomes lost when a stream is diverted into a confined channel. As pressure
+is an indication and measure of lost velocity, we may then reasonably look
+for greater pressure on the scale when a stream is confined after impact
+than when it discharges freely in every direction. Experimentally this is
+shown to be the case, for when the same oblong jet, discharged under the
+same conditions, impinged vertically upon a smooth plate, and gave a
+pressure of 71 units, gave 87 units when discharged into a confined
+right-angled channel. This result emphasizes the necessity for confining
+streams of water whenever it is desired to receive the greatest pressure by
+arresting their velocity. Such streams will always endeavor to escape in
+the directions of least resistance, and, therefore, in a turbine means
+should be provided to prevent any lateral deviation of the streams while
+passing through their buckets. So with screw propellers the great mass of
+surrounding water may be regarded as acting like a channel with elastic
+sides, which permits the area enlarging as the velocity of a current
+passing diminishes. The experiments thus far described have been made with
+jets of an oblong shape, and they give results differing in some degree
+from those obtained with circular jets. Yet as the general conclusions from
+both are found the same, it will avoid unnecessary prolixity by using the
+data from experiments made with a circular jet of 0.05 square inch area,
+discharging a stream at the rate of 40 ft. per second. This amounts to 52
+lb. of water per minute with an available head of 25 ft., or 1,300
+foot-pounds per minute. The tubes which received and directed the course of
+this jet were generally of lead, having a perfectly smooth internal
+surface, for it was found that with a rougher surface the flow of water is
+retarded, and changes occur in the data obtained. Any stream having its
+course changed presses against the body causing such change, this pressure
+increasing in proportion to the angle through which the change is made, and
+also according to the radius of a curve around which it flows. This fact
+has long been known to hydraulic engineers, and formulæ exist by which such
+pressures can be determined; nevertheless, it will be useful to study these
+relations from a somewhat different point of view than has been hitherto
+adopted, more particularly as they bear upon the construction of screw
+propellers and turbines; and by directing the stream, AB, Fig. 3,
+vertically into a tube 3/8 in. internal diameter and bent so as to turn the
+jet horizontally, and placing the whole arrangement upon a compound
+weighing machine, it is easy to ascertain the downward pressure, AB, due to
+impact, and the horizontal pressures, CB, due to reaction. In theoretical
+investigations it may be convenient to assume both these pressures exactly
+equal, and this has been done in the paper "On Screw Propellers" already
+referred to; but this brings in an error of no importance so far as general
+principles are involved, but one which destroys much of the value such
+researches might, otherwise possess for those who are engaged in the
+practical construction of screw propellers or turbines. The downward impact
+pressure, AB, is always somewhat greater than the horizontal reaction, BC,
+and any proportions between these two can only be accurately ascertained by
+trials. In these particular experiments the jet of water flowed 40 ft. per
+second through an orifice of 0.05 square inch area, and in every case its
+course was bent to a right angle. The pressures for impact and reaction
+were weighed coincidently, with results given by columns 1 and 2, Table II.
+
+[Illustration: FIG. 3]
+
+[Illustration: FIG. 4]
+
+_Table II.--Impact and Reaction in Confined Channels._
+
+-----------------------------+-------+---------+----------+-------
+Number of column.            |   1   |    2    |    3     |   4
+-----------------------------+-------+---------+----------+-------
+Description of experiments.  |Impact.|Reaction.|Resultant.| Angles
+                             |       |         |          |  ABS.
+-----------------------------+-------+---------+----------+-------
+Smooth London tube, 1¾ in.   |  71   |   62    |  94.25   |   49°
+  mean radius.               |       |         |          |
+                             |       |         |          |
+Rough wrought iron tube,     |  78   |   52    |  98.75   |  56.5°
+  1¾ in.                     |       |         |          |
+                             |       |         |          |
+Smooth leaden tube bent to a |  71   |   40    |  81.5    |   60
+  sharp right angle.         |       |         |          |
+-----------------------------+-------+---------+----------+------
+
+The third column is obtained by constructing a parallelogram of forces,
+where impact and reaction form the measures of opposing sides, and it
+furnishes the resultant due to both forces. The fourth column gives the
+inclination ABS, at which the line of impact must incline toward a plane
+surface RS, Fig. 3, so as to produce this maximum resultant perpendicularly
+upon it; as the resultant given in column 3 indicates the full practical
+effect of impact and reaction. When a stream has its direction changed to
+one at right angles to its original course, and as such a changed direction
+is all that can be hoped for by ordinary screw propellers, the figures in
+column 3 should bear some relationship to such cases. Therefore, it becomes
+an inquiry of some interest as to what angle of impact has been found best
+in those screw propellers which have given the best results in practical
+work. Taking one of the most improved propellers made by the late Mr.
+Robert Griffiths, its blades do not conform to the lines of a true screw,
+but it is an oblique paddle, where the acting portions of its blades were
+set at 48 deg. to the keel of the ship or 42 deg. to the plane of rotation.
+Again, taking a screw tug boat on the river Thames, with blades of a
+totally different form to those used by Mr. Griffiths, we still find them
+set at the same angle, namely, 48 deg. to the keel or 42 deg. to the plane
+of rotation. An examination of other screws tends only to confirm these
+figures, and they justify the conclusion that the inclinations of blades
+found out by practice ought to be arrived at, or at any rate approached, by
+any sound and reliable theory; and that blades of whatever form must not
+transgress far from this inclination if they are to develop any
+considerable efficiency. Indeed, many favorable results obtained by
+propellers are not due to their peculiarities, but only to the fact that
+they have been made with an inclination of blade not far from 42 deg. to
+the plan of rotation. Referring to column 4, and accepting the case of
+water flowing through a smooth tube as analogous to that of a current
+flowing within a large body of water, it appears that the inclination
+necessary to give the highest resultant pressure is an angle of 49 deg.,
+and this corresponds closely enough with the angle which practical
+constructors of screw propellers have found to give the best results.
+Until, therefore, we can deal with currents after they have been
+discharged from the blades of a propeller, it seems unlikely that anything
+can be done by alterations in the pitch of a propeller. So far as concerns
+theory, the older turbines were restricted to such imperfect results of
+impact and reaction as might be obtained by turning a stream at right
+angles to its original course; and the more scientific of modern turbine
+constructors may fairly claim credit for an innovation by which practice
+gave better results than theory seemed to warrant; and the consideration of
+this aspect of the question will form the concluding subject of the present
+paper. Referring again to Fig. 3, when a current passes round such a curve
+as the quadrant of a circle, its horizontal reaction appears as a pressure
+along _c_ B, which is the result of the natural integration of all the
+horizontal components of pressures, all of which act perpendicularly to
+each element of the concave surface along which the current flows. If, now,
+we add another quadrant of a circle to the curve, and so turn the stream
+through two right angles, or 180 deg., as shown by Fig. 4, then such a
+complete reversal of the original direction represents the carrying of it
+back again to the highest point; it means the entire destruction of its
+velocity, and it gives the maximum pressure obtainable from a jet of water
+impinging upon a surface of any form whatsoever. The reaction noticed in
+Fig. 3 as acting along _c_ B is now confronted by an impact of the now
+horizontal stream as it is turned round the second 90 deg. of curvature,
+and reacts also vertically downward. It would almost seem as if the first
+reaction from B to F should be exactly neutralized by the second impact
+from F to D. But such is not the case, as experiment shows an excess of the
+second impact over the first reaction amounting to six units, and shows
+also that the behavior of the stream through its second quadrant is
+precisely similar in kind to the first, only less in degree. Also the
+impact takes place vertically in one case and horizontally in the other.
+The total downward pressure given by the stream when turned 180 deg. is
+found by experiment thus: Total impact and reaction from 180 deg. change in
+direction of current = 132 units; and by deducting the impact 71 units, as
+previously measured, the new reaction corresponds with an increase of 61
+units above the first impact. It also shows an increase of 37.75 units
+above the greatest resultant obtained by the same stream turned through 90
+deg. only. Therefore, in designing a screw propeller or turbine, it would
+seem from these experiments desirable to aim at changing the direction of
+the stream, so far as possible, into one at 180 deg. to its original
+course, and it is by carrying out this view, so far as the necessities of
+construction will permit, that the scientifically designed modern turbine
+has attained to that prominence which it holds at present over all
+hydraulic motors. Much more might be written to extend and amplify the
+conclusions that can be drawn from the experiments described in the present
+paper, and from many others made by the writer, but the exigencies of time
+and your patience alike preclude further consideration of this interesting
+and important subject.
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED TEXTILE MACHINERY.
+
+
+[Illustration: THE TEXTILE EXHIBITION, ISLINGTON.]
+
+In the recent textile exhibition at Islington, one of the most extensive
+exhibits was that, of Messrs. James Farmer and Sons, of Salford. The
+exhibit consists of a Universal calender, drying machines, patent creasing,
+measuring, and marking machines, and apparatus for bleaching, washing,
+chloring, scouring, soaping, dunging, and dyeing woven fabrics. The purpose
+of the Universal calender is, says the _Engineer_, to enable limited
+quantities of goods to be finished in various ways without requiring
+different machines. The machine consists of suitable framing, to which is
+attached all the requisite stave rails, batching apparatus, compound
+levers, top and bottom adjusting screws, and level setting down gear, also
+Stanley roller with all its adjustments. It is furthermore supplied with
+chasing arrangement and four bowls; the bottom one is of cast iron, with
+wrought iron center; the next is of paper or cotton; the third of chilled
+iron fitted for heating by steam or gas, and the top of paper or cotton. By
+this machine are given such finishes as are known as "chasing finish" when
+the thready surface is wanted; "frictioning," or what is termed "glazing
+finish," "swigging finish," and "embossing finish;" the later is done by
+substituting a steel or copper engraved roller in place of the friction
+bowl. This machine is also made to I produce the "Moire luster" finish. The
+drying machine consists of nineteen cylinders, arranged with stave rails
+and plaiting down apparatus. These cylinders are driven by bevel wheels, so
+that each one is independent of its neighbor, and should any accident occur
+to one or more of the cylinders or wheels, the remaining ones can be run
+until a favorable opportunity arrives to repair the damage. A small
+separate double cylinder diagonal engine is fitted to this machine, the
+speed of which can be adjusted for any texture of cloth, and being of the
+design it is, will start at once on steam being turned one. The machine
+cylinders are rolled by a special machine for that purpose, and are
+perfectly true on the face. Their insides are fitted with patent buckets,
+which remove all the condensed water. In the machine exhibited, which is
+designed for the bleaching, washing, chloring, and dyeing, the cloth is
+supported by hollow metallic cylinders perforated with holes and corrugated
+to allow the liquor used to pass freely through as much of the cloth as
+possible; the open ends of the cylinders are so arranged that nearly all of
+their area is open to the action of the pump. The liquor, which is drawn
+through the cloth into the inside of the cylinders by the centrifugal
+pumps, is discharged back into the cistern by a specially constructed
+discharge pipe, so devised that the liquor, which is sent into it with
+great force by the pump, is diverted so as to pour straight down in order
+to prevent any eddies which could cause the cloth to wander from its
+course. The cloth is supported to and from the cylinders by flat perforated
+plates in such a manner that the force of the liquor cannot bag or displace
+the threads of the cloth, and by this means also the liquor has a further
+tendency to penetrate the fibers of the cloth. Means are provided for
+readily and expeditiously cleansing the entire machine. The next machine
+which we have to notice in this exhibit is Farmer's patent marking and
+measuring machine, the purpose of which is to stamp on the cloths the
+lengths of the same at regular distances. It is very desirable that drapers
+should have some simple means of discovering at a glance what amount of
+material they have in stock without the necessity of unrolling their cloth
+to measure it, and this machine seems to perfectly meet the demands of the
+case. The arrangement for effecting the printing and inking is shown in our
+engraving at A. It is contained within a small disk, which can be moved at
+will, so that it can be adapted to various widths of cloth or other
+material. A measuring roller runs beside the printing disk, and on this is
+stamped the required figures by a simple contrivance at the desired
+distances, say every five yards. The types are linked together into a
+roller chain which is carried by the disk, A, and they ink themselves
+automatically from a flannel pad. The machine works in this way: The end of
+the piece to be measured is brought down until it touches the surface of
+the table, the marker is turned to zero, and also the finger of the dial on
+the end of the measuring roller. The machine is then started, and the
+lengths are printed at the required distances until it becomes necessary to
+cut out the first piecing or joint in the fabric. The dial registers the
+total length of the piece.
+
+       *       *       *       *       *
+
+
+
+
+ENDLESS ROPE HAULAGE.
+
+
+In the North of England Report, the endless rope systems are classified as
+No. 1 and No 2 systems. No. 1, which has the rope under the tubs, is said
+to be in operation in the Midland counties. To give motion to the rope a
+single wheel is used, and friction for driving the rope is supplied either
+by clip pulleys or by taking the rope over several wheels. The diagram
+shows an arrangement for a tightening arrangement. One driving wheel is
+used, says _The Colliery Guardian_, and the rope is kept constantly tight
+by passing it round a pulley fixed upon a tram to which a heavy weight is
+attached. Either one or two lines of rails are used. When a single line is
+adopted the rope works backward and forward, only one part being on the
+wagon way and the other running by the side of the way. When two lines are
+used the ropes move always in one direction, the full tubs coming out on
+one line and the empties going in on the other. The rope passes under the
+tubs, and the connection is made by means of a clamp or by sockets in the
+rope, to which the set is attached by a short chain. The rope runs at a
+moderately high speed.
+
+[Illustration: TIGHTENING ARRANGEMENT--ENDLESS ROPE HAULAGE.]
+
+No. 2 system was peculiar to Wigan. A double line of rails is always used.
+The rope rests upon the tubs, which are attached to the rope either singly
+or in sets varying in number from two to twelve. The other engraving shows
+a mode of connection between the tubs and the rope by a rope loop as shown.
+
+[Illustration: ATTACHMENT TO ENDLESS ROPE "OVER."]
+
+The tubs are placed at a regular distance apart, and the rope works slowly.
+Motion is given to the rope by large driving pulleys, and friction is
+obtained by taking the rope several times round the driving pulley.
+
+       *       *       *       *       *
+
+
+
+
+A RELIABLE WATER FILTER.
+
+
+Opinions are so firmly fixed at present that water is capable of carrying
+the germs of disease that, in cases of epidemics, the recommendation is
+made to drink natural mineral waters, or to boil ordinary water. This is a
+wise measure, assuredly; but mineral waters are expensive, and, moreover,
+many persons cannot get used to them. As for boiled water, that is a
+beverage which has no longer a normal composition; a portion of its salts
+has become precipitated, and its dissolved gases have been given off. In
+spite of the aeration that it is afterward made to undergo, it preserves an
+insipid taste, and I believe that it is not very digestible. I have
+thought, then, that it would be important, from a hygienic standpoint, to
+have a filter that should effectually rid water of all the microbes or
+germs that it contains, while at the same time preserving the salts or
+gases that it holds in solution. I have reached such a result, and,
+although it is always delicate to speak of things that one has himself
+done, I think the question is too important to allow me to hold back my
+opinion in regard to the apparatus. It is a question of general hygiene
+before which my own personality must disappear completely.
+
+In Mr. Pasteur's laboratory, we filter the liquids in which microbes have
+been cultivated, so as to separate them from the medium in which they
+exist. For this purpose we employ a small unglazed porcelain tube that we
+have had especially constructed therefor. The liquid traverses the porous
+sides of this under the influence of atmospheric pressure, since we cause a
+vacuum around the tube by means of an air-pump. We collect in this way,
+after several hours, a few cubic inches of a liquid which is absolutely
+pure, since animals may be inoculated with it without danger to them, while
+the smallest quantity of the same liquid, when not filtered, infallibly
+causes death.
+
+This is the process that I have applied to the filtration of water. I have
+introduced into it merely such modifications as are necessary to render the
+apparatus entirely practical. My apparatus consists of an unglazed
+porcelain tube inverted upon a ring of enameled porcelain, forming a part
+thereof, and provided with an aperture for the outflow of the liquid. This
+tube is placed within a metallic one, which is directly attached to a cock
+that is soldered to the service pipe. A nut at the base that can be
+maneuvered by hand permits, through the intermedium of a rubber washer
+resting upon the enameled ring, of the tube being hermetically closed.
+
+Under these circumstances, when the cock is turned on, the water fills the
+space between the two tubes and slowly filters, under the influence of
+pressure, through the sides of the porous one, and is freed from all solid
+matter, including the microbes and germs, that it contains. It flows out
+thoroughly purified, through the lower aperture, into a vessel placed there
+to receive it.
+
+I have directly ascertained that water thus filtered is deprived of all its
+germs. For this purpose I have added some of it (with the necessary
+precautions against introducing foreign organisms) to very changeable
+liquids, such as veal broth, blood, and milk, and have found that there was
+no alteration. Such water, then, is incapable of transmitting the germs of
+disease.
+
+[Illustration: CHAMBERLAND'S WATER FILTER.]
+
+With an apparatus like the one here figured, and in which the filtering
+tube is eight inches in length by about one inch in diameter, about four
+and a half gallons of water per day may be obtained when the pressure is
+two atmospheres--the mean pressure in Mr. Pasteur's laboratory, where my
+experiments were made. Naturally, the discharge is greater or less
+according to the pressure. A discharge of three and a half to four and a
+half gallons of water seems to me to be sufficient for the needs of an
+ordinary household. For schools, hospitals, barracks, etc., it is easy to
+obtain the necessary volume of water by associating the tubes in series.
+The discharge will be multiplied by the number of tubes.
+
+In the country, or in towns that have no water mains, it will be easy to
+devise an arrangement for giving the necessary pressure. An increase in the
+porosity of the filtering tube is not to be thought of, as this would allow
+very small germs to pass. This filter being a perfect one, we must expect
+to see it soil quickly. Filters that do not get foul are just the ones that
+do not filter. But with the arrangement that I have adopted the solid
+matters deposit upon the external surface of the filter, while the inner
+surface always remains perfectly clean. In order to clean the tube, it is
+only necessary to take it out and wash it vigorously. As the tube is
+entirely of porcelain, it may likewise be plunged into boiling water so as
+to destroy the germs that may have entered the sides or, better yet, it may
+be heated over a gas burner or in an ordinary oven. In this way all the
+organic matter will be burned, and the tube will resume its former
+porosity.--_M. Chamberland, La Nature._
+
+       *       *       *       *       *
+
+
+
+
+SIMPLE DEVICES FOR DISTILLING WATER.
+
+
+The alchemists dreamed and talked of that universal solvent which they so
+long and vainly endeavored to discover; still, for all this, not only the
+alchemist of old, but his more immediate successor, the chemist of to-day,
+has found no solvent so universal as water. No liquid has nearly so wide a
+range of dissolving powers, and, taking things all round, no liquid
+exercises so slight an action upon the bodies dissolved--evaporate the
+water away, and the dissolved substance is obtained in an unchanged
+condition; at any rate, this is the general rule.
+
+The function of water in nature is essentially that of a solvent or a
+medium of circulation; it is not, in any sense, a food, yet without it no
+food can be assimilated by an animal. Without water the solid materials of
+the globe would be unable to come together so closely as to interchange
+their elements; and unless the temperatures were sufficiently high to
+establish an igneous fluidity, such as undoubtedly exists in the sun, there
+would be no circulation of matter to speak of, and the earth would be, as
+it were, locked up or dead.
+
+When we look upon water as the nearest approach to a universal solvent that
+even the astute scientist of to-day has been able to discover, who can
+wonder that it is never found absolutely pure in nature? For wherever it
+accumulates it dissolves something from its surroundings. Still, in a
+rain-drop just formed we have very nearly pure water; but even this
+contains dissolved air to the extent of about one-fiftieth of its volume,
+and as the drop falls downward it takes up such impurities as may be
+floating in the atmosphere; so that if our rain-drop is falling
+immediately after a long drought, it becomes charged with nitrate or
+nitrite of ammonia and various organic matters--perhaps also the spores or
+germs of disease. Thus it will be seen that rain tends to wonderfully clear
+or wash the atmosphere, and we all know how much a first rain is
+appreciated as an air purifier, and how it carries down with it valuable
+food for plants. The rain-water, in percolating through or over the land,
+flows mainly toward the rivers, and in doing so it becomes more or less
+charged with mineral matter, lime salts and common salt being the chief of
+them; while some of that water which has penetrated more deeply into the
+earth takes up far more solid matter than is ordinarily found in river
+water. The bulk of this more or less impure water tends toward the ocean,
+taking with it its load of salt and lime. Constant evaporation, of course,
+takes place from the surface of the sea, so that the salt and lime
+accumulate, this latter being, however, ultimately deposited as shells,
+coral, and chalk, while nearly pure or naturally distilled water once more
+condenses in the form of clouds. This process, by which a constant supply
+of purified water is kept up in the natural economy, is imitated on a small
+scale when water is converted into steam by the action of heat, and this
+vapor is cooled so as to reproduce liquid water, the operation in question
+being known as distillation.
+
+For this purpose an apparatus known as a still is required; and although by
+law one must pay an annual license fee for the right to use a still, it is
+not usual for the government authorities to enforce the law when a still is
+merely used for purifying water.
+
+One of the best forms of still for the photographer to employ consists of a
+tin can or bottle in which the water is boiled, and to this a tin tube is
+adapted by means of a cork, one end of this tin tube terminating in a coil
+passing through a tub or other vessel of cold water. A gas burner, as
+shown, is a convenient source of heat, and in order to insure a complete
+condensation of the vapor, the water in the cooling tub must be changed now
+and again.
+
+[Illustration]
+
+Sometimes the vapor is condensed by being allowed to play against the
+inside of a conical cover which is adapted to a saucepan, and is kept cool
+by the external application of cold water; and in this case the still takes
+the form represented by the subjoined diagrams; such compact and portable
+stills being largely employed in Ireland for the private manufacture of
+whisky.
+
+[Illustration]
+
+It is scarcely necessary to say that the condensed water trickles down on
+the inside of the cone, and flows out at the spout.
+
+An extemporized arrangement of a similar character may be made by passing a
+tobacco pipe through the side of a tin saucepan as shown below, and
+inverting the lid of the saucepan; if the lid is now kept cool by frequent
+changes of water inside it, and the pipe is properly adjusted so as to
+catch the drippings from the convex side of the lid, a considerable
+quantity of distilled water may be collected in an hour or so.
+
+The proportion of solid impurities present in water as ordinarily met with
+is extremely variable: rain water which has been collected toward the end
+of a storm contains only a minute fraction of a grain per gallon, while
+river or spring water may contain from less than thirty grains per gallon
+or so and upward. Ordinary sea water generally contains from three to four
+per cent. of saline matter, but that of the Dead Sea contains nearly
+one-fourth of its weight of salts.
+
+[Illustration]
+
+The three impurities of water which most interest the photographer are lime
+or magnesia salts, which give the so-called hardness; chlorides (as, for
+example, chloride of sodium or common salt), which throw down silver salts;
+and organic matter, which may overturn the balance of photographic
+operations by causing premature reduction of the sensitive silver
+compounds. To test for them is easy. Hardness is easily recognizable by
+washing one's hands in the water, the soap being curdled; but in many cases
+one must rather seek for a hard water than avoid it, as the tendency of
+gelatine plates to frill is far less in hard water than in soft water. It
+is, indeed, a common and useful practice to harden the water used for
+washing by adding half an ounce or an ounce of Epsom salts (sulphate of
+magnesia) to each bucket of water. Chlorides--chloride of sodium or common
+salt being that usually met with--may be detected by adding a drop or two
+of nitrate of silver to half a wineglassful of the water, a few drops of
+nitric acid being then added. A slight cloudiness indicates a trace of
+chlorides, and a decided milkiness shows the presence of a larger quantity.
+If it is wished to get a somewhat more definite idea of the amount, it is
+easy to make up a series of standards for comparison, by dissolving known
+weights of common salt in distilled or rain water, and testing samples of
+them side by side with the water to be examined.
+
+Organic matters may be detected by adding a little nitrate of silver to the
+water, filtering off from any precipitate of chloride of silver, and
+exposing the clear liquid to sunlight; a clean stoppered bottle being the
+most convenient vessel to use. The extent to which a blackening takes place
+may be regarded as approximately proportionate to the amount of organic
+matter present.
+
+Filtration on a small scale is not altogether a satisfactory mode of
+purifying water, as organic impurities often accumulate in the filter, and
+enter into active putrefaction when hot weather sets in.--_Photo. News._
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED FIRE-DAMP DETECTER.
+
+
+According to the London _Mining Journal_, Mr. W.E. Garforth, of Normanton,
+has introduced an ingenious invention, the object of which is to detect
+fire-damp in collieries with the least possible degree of risk to those
+engaged in the work. Mr. Garforth's invention, which is illustrated in the
+diagram given below, consists in the use of a small India rubber hand ball,
+without a valve of any description; but by the ordinary action of
+compressing the ball, and then allowing it to expand, a sample of the
+suspected atmosphere is drawn from the roof, or any part of the mine,
+without the great risk which now attends the operation of testing for gas
+should the gauze of the lamp be defective. The sample thus obtained is then
+forced through a small protected tube on to the flame, when if gas is
+present it is shown by the well-known blue cap and elongated flame. From
+this description, and from the fact that the ball is so small that it can
+be carried in the coat pocket, or, if necessary, in the waistcoat pocket,
+it will be apparent what a valuable adjunct Mr. Garforth's invention will
+prove to the safety-lamp. It has been supposed by some persons that
+explosions have been caused by the fire-trier himself, but owing to his own
+death in most cases the cause has remained undiscovered. This danger will
+now be altogether avoided. It is well known that the favorite form of lamp
+with the firemen is the Davy, because it shows more readily the presence of
+small quantities of gas; but the Davy was some years ago condemned, and is
+now strictly prohibited in all Belgian and many English mines. Recent
+experience, gained by repeated experiments with costly apparatus, has
+resulted in not only proving the Davy and some other descriptions of lamps
+to be unsafe, but some of our Government Inspectors and our most
+experienced mining engineers go so far as to say that "no lamp in a strong
+current of explosive gas is safe unless protected by a tin shield."
+
+[Illustration]
+
+If such is the case, Mr. Garforth seems to have struck the key-note when,
+in the recent paper read before the Midland Institute of Mining and Civil
+Engineers, and which we have now before us, he says: "It would seem from
+the foregoing remarks that in any existing safety-lamp where one
+qualification is increased another is proportionately reduced; so it is
+doubtful whether all the necessary requirements of sensitiveness,
+resistance to strong currents, satisfactory light, self-extinction, perfect
+combustion, etc., can ever be combined in one lamp."
+
+The nearest approach to Mr. Garforth's invention which we have ever heard
+of is that of a workman at a colliery in the north of England, who, more
+than twenty years ago, to avoid the trouble of getting to the highest part
+of the roof, used a kind of air pump, seven or eight feet long, to extract
+the gas from the breaks; and some five years ago Mr. Jones, of Ebbw Vale,
+had a similar idea. It appears that these appliances were so cumbersome,
+besides requiring too great length or height for most mines, and
+necessitating the use of both hands, that they did not come into general
+use. The ideas, however, are totally different, and the causes which have
+most likely led to the invention of the ball and protected tube were
+probably never thought of until recently; indeed, Mr. Garforth writes that
+he has only learned about them since his paper was read before the Midland
+Institute, and some weeks after his patent was taken out.
+
+No one, says Mr. Garforth, in his paper read before the Midland Institute,
+will, I presume, deny that the Davy is more sensitive than the tin shield
+lamp, inasmuch as in the former the surrounding atmosphere or explosive
+mixture has only one thickness of gauze to pass through, and that on a
+level with the flame; while the latter has a number of small holes and two
+or three thicknesses of gauze (according to the construction of the lamp),
+which the gas must penetrate before it reaches the flame. Moreover, the tin
+shield lamp, when inclined to one side, is extinguished (though not so
+easily as the Mueseler); and as the inlet holes are 6 inches from the top,
+it does not show a thin stratum of fire-damp near the roof as perceptibly
+as the Davy, which admits of being put in almost a horizontal position.
+Although the Davy lamp was, nearly fifty years ago, pronounced unsafe, by
+reason of its inability to resist an ordinary velocity of eight feet per
+second, yet it is still kept in use on account of its sensitiveness. Its
+advocates maintain that a mine can be kept safer by using the Davy, which
+detects small quantities of gas, and thereby shows the real state of the
+mine, than by a lamp which, though able to resist a greater velocity, is
+not so sensitive, and consequently is apt to deceive. Assuming the Davy
+lamp to be condemned (as it has already been in Belgium and in some English
+mines), the Stephenson and some of the more recently invented lamps
+pronounced unsafe, then if greater shielding is recommended the question
+is, what means have we for detecting small quantities of fire-damp?
+
+It would seem from the foregoing remarks that in any existing safety-lamp,
+where one qualification is increased another is proportionately reduced; so
+it is doubtful whether all the necessary requirements of sensitiveness,
+resistance to strong currents, satisfactory light, self-extinction, perfect
+combustion, etc., can ever be combined in one lamp. The object of the
+present paper is to show that with the assistance of the fire-damp
+detecter, the tin shield, or any other description of lamp, is made as
+sensitive as the Davy, while its other advantages of resisting velocity,
+etc., are not in any way interfered with. As a proof of this I may mention
+that a deputy of experience recently visited a working place to make his
+inspection. He reported the stall to be free from gas, but when the manager
+and steward visited it with the detecter, which they applied to the roof
+(where it would have been difficult to put even a small Davy), it drew a
+sample of the atmosphere which, on being put to the test tube in the
+tin-shield lamp, at once showed the presence of fire-damp. Out of
+twenty-eight tests in a mine working a long-wall face the Davy showed gas
+only eleven times, while the detecter showed it in every case. The
+detecter, as will be perceived from the one exhibited, and the accompanying
+sectional drawing, consists simply of an oval-shaped India rubber ball,
+fitted with a mouthpiece. The diameter is about 2¼ inches by 3 inches, its
+weight is two ounces, and it is so small that it can be carried without any
+inconvenience in the coat or even in the waistcoat pocket. Its capacity is
+such that all the air within it may be expelled by the compression of one
+hand.
+
+The mouthpiece is made to fit a tube in the bottom of the lamp, and when
+pressed against the India rubber ring on the ball-flange, a perfectly tight
+joint is made, which prevents the admission of any external air. The tube
+in the bottom of the lamp is carried within a short distance of the height
+of the wick-holder. It is covered at the upper end with gauze, besides
+being fitted with other thicknesses of gauze at certain distances within
+the tube; and if it be found desirable to further protect the flame against
+strong currents of air, a small valve may be placed at the inlet, as shown
+in the drawing. This valve is made of sufficient weight to resist the force
+of a strong current, and is only lifted from its seat by the pressure of
+the hand on the mouthpiece. It will be apparent from the small size and
+elasticity of the detecter that the test can easily be made with one hand,
+and when the ball is allowed to expand a vacuum is formed within it, and a
+sample of the atmosphere drawn from the breaks, cavities, or highest parts
+of the roof, or, of course, any portion of the mine. When the sample is
+forced through the tube near the flame, gas if present at once reveals
+itself by the elongation of the flame in the usual way, at the same time
+giving an additional proof by burning with a blue flame on the top of the
+test tube. If gas is not present, the distinction is easily seen by the
+flame keeping the same size, but burning with somewhat greater brightness,
+owing to the increased quality of oxygen forced upon it.
+
+I venture to claim for this method of detecting fire-damp among other
+advantages: 1. The detecter, on account of its size, can be placed in a
+break in the roof where an ordinary lamp--even a small Davy--could not be
+put, and a purer sample of the suspected atmosphere is obtained than would
+be the case even a few inches below the level of the roof, 2. The obtaining
+and testing of a sample in the manner above described takes away the
+possibility of an explosion, which might be the result if a lamp with a
+defective gauze were placed in an explosive atmosphere. No one knows how
+many explosions have not been caused by the fire-trier himself. This will
+now be avoided. (Although lamps fitted with a tin shield will be subjected
+to the same strict examination as hitherto, still they do not admit of the
+same frequent inspection as those without shields, for in the latter case
+each workman can examine his own lamp as an extra precaution; whereas the
+examination of the tin shield lamps will rest entirely with the lamp man.)
+3. The lamp can be kept in a pure atmosphere while the sample is obtained
+by the detecter, and at a greater height than the flame in a safety-lamp
+could be properly distinguished. The test can afterward be made in a safe
+place, at some distance from the explosive atmosphere; and, owing to the
+vacuum formed, the ball (without closing the mouthpiece) has been carried a
+mile or more without the gas escaping. 4. The detecter supplies a better
+knowledge of the condition of the working places, especially in breaks and
+cavities in the roof; which latter, with the help of a nozzle and staff,
+may be reached to a height of ten feet or more, by the detecter being
+pressed against the roof and sides, or by the use of a special form of
+detecter. 5. Being able at will to force the contents of the detecter on to
+the flame, the effects of an explosion inside the lamp need not be feared.
+(This danger being removed, admits, I think, of the glass cylinder being
+made of a larger diameter, whereby a better light is obtained; it may also
+be considered quite as strong, when used with the detecter, as a lamp with
+a small diameter, when the latter is placed in an explosive atmosphere.) 6.
+The use of the detecter will permit the further protection of the present
+tin shield lamp, by an extra thickness of gauze, if such addition is found
+advantageous in resisting an increased velocity. 7. In the Mueseler,
+Stephenson, and other lamps, where the flame is surrounded by glass, there
+is no means of using the wire for shot firing. The detecter tube, although
+protected by two thicknesses of gauze, admits of this being done by the use
+of a special form of valve turned by the mouthpiece of the detecter. The
+system of firing shots or using open lamps in the same pit where safety
+lamps are used is exceedingly objectionable; still, under certain
+conditions shots may be fired without danger. Whether safety lamps or
+candles are used, it is thought the use of the detecter will afford such a
+ready means of testing that more examinations will be made before firing a
+shot, thereby insuring greater safety. 8. In testing for gas with a safety
+lamp there is a fear of the light being extinguished, when the lamp is
+suddenly placed in a quantity of gas, or in endeavoring to get a very
+small light; this is especially the case with some kinds of lamps. With the
+detecter this is avoided, as a large flame can be used, which is considered
+by some a preferable means of testing for small quantities; and the test
+can be made without risk. Where gas is present in large quantities, the
+blue flame at the end of the test tube will be found a further proof. This
+latter result is produced by the slightest compression of the ball. (I need
+not point out the inconvenience and loss of time in having to travel a mile
+or more to relight.) As regards the use of the detecter with open lights,
+several of the foregoing advantages or modifications of them will apply.
+Instead of having to use the safety lamp as at present, it is thought that
+the working place will be more frequently examined, for a sample of the
+suspected atmosphere can be carried to a safe place and forced on to the
+naked light, when, if gas be present, it simply burns at the end of the
+mouthpiece like an ordinary gas jet. There are other advantages, such as
+examining the return airways without exposing the lamp, etc., which will be
+apparent, and become of more or less importance according to the conditions
+under which the tests are made.
+
+In conclusion, I wish to paint out that the practice adopted at some
+collieries, of having all the men supplied with the most approved lamp
+(such as the Mueseler or tin shield lamp) is not a safe one. If the
+strength of a chain is only equal to the weakest link, it may be argued
+that the safety of a mine is only equal to that of the most careless man or
+most unsafe lamp in it. If, therefore, the deputies, whose duty it is to
+look for gas and travel the most dangerous parts of the mine, are obliged
+to use the Davy on account of its sensitiveness, may it not be said that,
+as their lamps are exposed equally with the workmen's to the high
+velocities of air, they are the weak links in the safety of the mine? For
+the reasons given, I venture to submit that the difficulties and dangers I
+have mentioned will be largely reduced, if not wholly overcome, by the use
+of the fire-damp detecter.
+
+       *       *       *       *       *
+
+
+
+
+CAMERA ATTACHMENT FOR PAPER PHOTO NEGATIVES.
+
+
+In computing the weight of the various items for a photographic tour, the
+glass almost invariably comes out at the head of the list, and the farther
+or longer the journey, so much more does the weight of the plates stand out
+pre-eminent; indeed, if one goes out on a trip with only three dozen
+half-plates, the glass will probably weigh nearly as much as camera, backs,
+and tripod, in spite of the stipulation with the maker to supply plates on
+"thin glass."
+
+Next in importance to glass as a support comes paper, and it is quite easy
+to understand that the tourist in out of the way parts might be able to
+take an apparatus containing a roll of sensitive paper, when it would be
+altogether impracticable for him to take an equivalent surface of coated
+glass, and in such a case the roller slide becomes of especial value.
+
+The roller slide of Melhuish is tolerably well known, and is, we believe,
+now obtainable as an article of commerce. The slide is fitted up with two
+rollers, _a a_, and the sensitive sheets, _b b_, are gummed together,
+making one long band, the ends of which are gummed to pieces of paper
+always kept on the rollers. The sensitive sheets are wound off the left or
+reserve roller on to the right or exposed roller, until all are exposed.
+
+[Illustration]
+
+The rollers are supported on springs, _a¹ a¹_, to render their motion
+equal; they are turned by the milled heads, _m m_, and clamped when each
+fresh sheet is brought into position by the nuts, _a² a²_. _c_, is a board
+which is pressed forward by springs, _c¹ c¹_, so as to hold the sheet to be
+exposed, and keep it smooth against the plate of glass, _d_; when the sheet
+has been exposed, the board is drawn back from the glass in order to
+release the exposed sheet, and allow it to be rolled on the exposed roller;
+the board is kept back while this is being done by turning the square rod,
+_c²_, half round, so that the angles of the square will not pass back
+through the square opening until again turned opposite to it; _e e_ are
+doors, by opening which the operator can see (through the yellow glass, _y
+y_) to adjust the position of the sensitive sheets when changing them.
+
+The remarkable similarity of such a slide to the automatic printing-frame
+described last week will strike the reader; and, like the printing-frame,
+it possesses the advantage of speed in working--no small consideration to
+the photographer in a distant, and possibly hostile, country.
+
+Fine paper well sized with an insoluble size and coated with a sensitive
+emulsion is, we believe, the very best material to use in the roller slide;
+and such a paper might be made in long lengths at a very low price, a
+coating machine similar to that constructed for use in making carbon tissue
+being employed. We have used such paper with success, and hope that some
+manufacturer will introduce it into commerce before long. But the question
+suggests itself, how are the paper negatives to be rendered transparent,
+and how is the grain of the paper to be obliterated? Simply by pressure, as
+extremely heavy rolling will render such paper almost as transparent as
+glass, a fact abundantly demonstrated by Mr. Woodbury in his experiments on
+the Photo-Filigrane process, and confirmed by some trials which we have
+made.
+
+It must be confessed that roller slide experiments which we have made with
+sensitive films supported on gelatine sheets, or on such composite sheets
+as the alternate rubber and collodion pellicle of Mr. Warnerke, have been
+hardly satisfactory--possibly, however, from our own want of skill; while
+no form of the Calotype process which we have tried has proved so
+satisfactory as gelatino-bromide paper.--_Photo. News_.
+
+       *       *       *       *       *
+
+
+
+
+INSTANTANEOUS PHOTO SHUTTER.
+
+
+M. Audra, in the name of M. Braun, of Angoulême, has presented to the Photo
+Society of France a new instantaneous shutter. The shutter is formed by a
+revolving metallic disk out of which a segment has been taken. This disk is
+placed in the center of the diaphragms, in order to obtain the greatest
+rapidity combined with the least possible distance to travel. On the axis
+to which this circular disk is fixed is a small wheel, to which is attached
+a piece of string, and when the disk is turned round for the exposure the
+string is wound round the wheel. If the string be pulled, naturally the
+disk will revolve back to its former position so much the more quickly the
+more violently the string is pulled. M. Braun has replaced the hand by a
+steel spring attached to the drum of the lens (Fig. 2) By shortening or
+lengthening the string, more or less rapid exposures may be obtained.
+
+[Illustration: AAA, lens; B, aperture of lens; C, metallic disk; D,
+wheel on the axis; E, cord or string; E¹E¹E¹E¹, knots in string; G, steel
+spring; H, catch; K, socket for catch.]
+
+       *       *       *       *       *
+
+
+
+
+SULPHUROUS ACID.--EASY METHOD OF PREPARATION FOR PHOTOGRAPHIC PURPOSES.
+
+
+Within a short period sulphurous acid has become an important element in
+the preparation of an excellent pyro developer for gelatine plates; and as
+it is more or less unstable in its keeping qualities, some easy method of
+preparing a small quantity which shall have a uniform strength is
+desirable. A method recently described in the _Photographic News_ will
+afford the amateur photographer a ready way of preparing a small quantity
+of the acid.
+
+[Illustration]
+
+In the illustration given above, A and B are two bottles, both of which can
+be closed tightly with corks. A hole is made in the cork in the bottle, A,
+a little smaller than the glass tube which connects A and B. It is filed
+out with a rat-tail file until it is large enough to admit the tube very
+tightly. The tube may be bent easily, by being heated over a common
+fish-tail gas burner or over the top of the chimney of a kerosene lamp, so
+as to form two right angles, one end extending close to the bottom of the
+bottle B as shown.
+
+Having fitted up the apparatus, about two ounces of hyposulphite of soda
+are placed in the bottle A, while the bottle B is about three-fourths
+filled with water--distilled or melted ice water is to be preferred; some
+sulphuric acid--about two ounces--is now diluted with about twice its bulk
+of water, by first putting the water into a dish and pouring in the acid in
+a steady stream, stirring meanwhile. It is well to set the dish in a sink,
+to avoid any damage which might occur through the breaking of the dish by
+the heat produced; when cool, the solution is ready for use and may be kept
+in a bottle.
+
+The cork which serves to adapt the bent tube to the bottle A is now just
+removed for an instant, the other end remaining in the water in bottle B,
+and about two or three ounces of the dilute acid are poured in upon the
+hyposulphite, after which the cork is immediately replaced.
+
+Sulphurous acid is now evolved by the action of the acid on the hypo, and
+as the gas is generated it is led as a series of bubbles through the water
+in the bottle B as shown. The air space above the water in bottle B soon
+becomes filled by displacement with sulphurous acid gas, which is a little
+over twice as heavy as air; so in order to expedite the complete saturation
+of the water, it is convenient to remove the bottle A with its tube from
+bottle B, and after having closed the latter by its cork or stopper, to
+agitate it thoroughly by turning the bottle upside down. As the sulphurous
+acid gas accumulated in the air space over the water is absorbed by the
+water, a partial vacuum is created, and when the stopper is eased an inrush
+of air may be noted. When, after passing fresh gas through the liquid for
+some minutes, no further inrush of air is noted on easing the stopper as
+before described after agitating the bottle, it may be concluded that the
+water is thoroughly saturated with sulphurous acid and is strong enough for
+immediate use. More gas can be generated by adding more dilute sulphuric
+acid to the hypo until the latter is decomposed; then it should be thrown
+aside, and a fresh charge put in the bottle. On preparing the solution it
+is well to set the bottles on the outside ledge of the window, or in some
+other open situation where no inconvenience will result from the escape of
+the excess of sulphurous gas as it bubbles through the water.
+
+The solution of sulphurous acid, if preserved at all, ought to be kept in
+small bottles, completely filled and perfectly closed; but as it is very
+easy to saturate a considerable quantity of water with sulphurous acid gas
+in a short time, there is but little inducement to use a solution which may
+possibly have become weakened by keeping.
+
+Care should be taken not to add too much dilute acid to the hypo at a time,
+else excessive effervescence will occur, and the solution will froth over
+the top of the bottle.
+
+       *       *       *       *       *
+
+
+
+
+THE NATIONAL MONUMENT AT ROME.
+
+
+About three years ago the Italian Government invited the architects and
+artists of the world to furnish competitive designs for a national monument
+to be erected to the memory of King Victor Emanuel II. at Rome. More than
+$1,800,000 were appropriated for the monument exclusive of the foundation.
+It is very seldom that an artist has occasion to carry out as grand and
+interesting a work as this was to be: the representation of the creator of
+the Italian union in the new capitol of the new state surrounded by the
+ruins and mementos of a proud and mighty past. Prizes of $10,000, $6,000,
+and $4,000 were donated for the first, second, and third prize designs
+respectively. Designs were entered, not only from Italy, but also from
+Germany, France, Norway, Sweden, England, and America, and even from
+Caucasus and Japan.
+
+[Illustration: THE UNION OF ITALY. SACCONI'S PRIZE DESIGN FOR THE
+NATIONAL MONUMENT, ROME, ITALY.]
+
+The height and size of the monument were not determined on, nor was the
+exact location, and the competitors had full liberty in relation to the
+artistic character of the monument, and it was left for them to decide
+whether it should be a triumphal arch, a column, a temple, a mausoleum, or
+any other elaborate design. This great liberty given to the competitors was
+of great value and service to the monument commission, as it enabled them
+to decide readily what the character of the monument should be but it was a
+dangerous point for the artists, at which most of them foundered. The
+competition was resultless. Two prizes were given, but new designs had to
+be called for, which were governed more or less by a certain programme
+issued by the committee.
+
+In place of the Piazza de Termini, a square extending from the church of
+St. Maria degli Angeli to the new Via Nazionale, to which preference was
+given by the competitors, the heights of Aracoeli were chosen. The monument
+was to be erected at this historic place in front of the side wall of the
+church, with the center toward the Corso, high above the surrounding
+buildings. The programme called for an equestrian statue of the King
+located in front of an architectural background which was to cover the old
+church walls, and was to be reached by a grand staircase.
+
+Even the result of this second competition was not definite, but as the
+designers were guided by the programme, the results obtained were much more
+satisfactory. The commission decided not to award the first prize, but
+honored the Italian architects Giuseppi Sacconi and Manfredo Manfredi, and
+the German Bruno Schmitz, with a prize of $2,000 each; and requested them
+to enter into another competition and deliver their models within four
+months, so as to enable the commission to come to a final decision. On June
+18, the commission decided to accept Sacconi's design for execution, and
+awarded a second prize of $2,000 to Manfredi.
+
+Sacconi's design, shown opposite page, cut taken from the _Illustrirte
+Zeitung_, needs but little explanation. An elegant gallery of sixteen
+Corinthian columns on a high, prominent base is crowned by a high attica
+and flanked by pavilions. It forms the architectural background for the
+equestrian statue, and is reached by an elaborately ornamented staircase.
+
+Manfredi's design shows a handsomely decorated wall in place of the
+gallery, and in front of the wall an amphitheater is arranged, in the
+center of which the equestrian statue is placed. Bruno Schmitz' design
+shows a rich mosaic base supporting an Ionic portico, from the middle of
+which a six column Corinthian "pronaos" projects, which no doubt would have
+produced a magnificent effect in the streets of Rome.
+
+       *       *       *       *       *
+
+
+
+
+ON THE EVOLUTION OF FORMS OF ORNAMENT.
+
+[Footnote: From a paper by Prof. Jacobsthal in the _Transactions_ of the
+Archæological Society of Berlin.--_Nature_.]
+
+
+The statement that modern culture can be understood only through a study of
+all its stages of development is equally true of its several branches.
+
+Let us assume that decorative art is one of these. It contains in itself,
+like language and writing, elements of ancient and even of prehistoric
+forms, but it must, like these other expressions of culture, which are
+forever undergoing changes, adapt itself to the new demands which are made
+upon it, not excepting the very arbitrary ones of fashion; and it is owing
+to this cause that, sometimes even in the early stages of its development,
+little or nothing of its original form is recognizable. Investigations the
+object of which is to clear up this process of development as far as
+possible are likely to be of some service; a person is more likely to
+recognize the beauties in the details of ornamental works of art if he has
+an acquaintance with the leading styles, and the artist who is freed from
+the bondage of absolute tradition will be put into a better position to
+discriminate between accidental and arbitrary and organic and legitimate
+forms, and will thus have his work in the creation of new ones made more
+easy for him.
+
+Hence I venture to claim some measure of indulgence in communicating the
+results of the following somewhat theoretical investigations, as they are
+not altogether without a practical importance. I must ask the reader to
+follow me into a modern drawing-room, not into one that will dazzle us with
+its cold elegance, but into one whose comfort invites us to remain in it.
+
+The simple stucco ceiling presents a central rosette, which passes over by
+light conventional floral forms into the general pattern of the ceiling.
+The frieze also, which is made of the same material, presents a similar but
+somewhat more compact floral pattern as its chief motive. Neither of these,
+though they belong to an old and never extinct species, has as yet attained
+the dignity of a special name.
+
+The walls are covered with a paper the ornamentation of which is based upon
+the designs of the splendid textile fabrics of the middle ages, and
+represents a floral pattern of spirals and climbing plants, and bears
+evident traces of the influence of Eastern culture. It is called a
+pomegranate or pine-apple pattern, although in this case neither
+pomegranates nor pine-apples are recognizable.
+
+Similarly with respect to the pattern of the coverings of the chairs and
+sofas and of the stove-tiles; these, however, show the influence of Eastern
+culture more distinctly.
+
+The carpet also, which is not a true Oriental one, fails to rivet the
+attention, but gives a quiet satisfaction to the eye, which, as it were,
+casually glances over it, by its simple pattern, which is derived from
+Persian-Indian archetypes (Cashmere pattern, Indian palmettas), and which
+is ever rhythmically repeating itself (see Fig. 1).
+
+[Illustration: FIG. 1.]
+
+The floral pattern on the dressing-gown of the master of the house, as well
+as on the light woolen shawl that is thrown round the shoulders of his
+wife, and even the brightly colored glass knicknacks on the mantel-piece,
+manufactured in Silesia after the Indian patterns of the Reuleaux
+collection, again show the same motive; in the one case in the more
+geometrical linear arrangement, in the other in the more freely entwined
+spirals.
+
+Now you will perhaps permit me to denominate these three groups of patterns
+that occur in our new home fabrics as modern patterns. Whether we shall in
+the next season be able, in the widest sense of the word, to call these
+patterns modern naturally depends on the ruling fashion of the day, which
+of course cannot be calculated upon (Fig. 2).
+
+[Illustration: FIG. 2.]
+
+I beg to be allowed to postpone the nearer definition of the forms that
+occur in the three groups, which, however, on a closer examination all
+present a good deal that they have in common. Taking them in a general way,
+they all show a leaf-form inclosing an inflorescence in the form of an ear
+or thistle; or at other times a fruit or a fruit-form. In the same way with
+the stucco ornaments and the wall-paper pattern.
+
+The Cashmere pattern also essentially consists of a leaf with its apex
+laterally expanded; it closes an ear-shaped flower-stem, set with small
+florets, which in exceptional cases protrude beyond the outline of the
+leaf; the whole is treated rigorously as an absolute flat ornament, and
+hence its recognition is rendered somewhat more difficult. The blank
+expansion of the leaf is not quite unrelieved by ornament, but is set off
+with small points, spots, and blossoms. This will be thought less strange
+if we reflect on the Eastern representations of animals, in the portrayal
+of which the flat expanses produced by the muscle-layers are often treated
+from a purely decorative point of view, which strikes us as an exaggeration
+of convention.
+
+[Illustration: FIG. 3.]
+
+One cannot go wrong in taking for granted that plant-forms were the
+archetypes of all these patterns. Now we know that it holds good, as a
+general principle in the history of civilization, that the tiller of the
+ground supplants the shepherd, as the shepherd supplants the hunter; and
+the like holds also in the history of the branch of art we are
+discussing--representations of animals are the first to make their
+appearance, and they are at this period remarkable for a wonderful
+sharpness of characterization. At a later stage man first begins to exhibit
+a preference for plant-forms as subjects for representation, and above all
+for such as can in any way be useful or hurtful to him. We, however, meet
+such plant-forms used in ornament in the oldest extant monuments of art in
+Egypt, side by side with representations of animals; but the previous
+history of this very developed culture is unknown. In such cases as afford
+us an opportunity of studying more primitive though not equally ancient
+stages of culture, as for instance among the Greeks, we find the above
+dictum confirmed, at any rate in cases where we have to deal with the
+representation of the indigenous flora as contradistinguished from such
+representations of plants as were imported from foreign civilizations. In
+the case that is now to occupy us, we have not to go back so very far in
+the history of the world.
+
+[Illustration: FIG. 4.]
+
+The ornamental representations of plants are of two kinds. Where we have to
+deal with a simple pictorial reproduction of plants as symbols (laurel
+branches, boughs of olive and fir, and branches of ivy), _i. e._, with a
+mere characteristic decoration of a technical structure, stress is laid
+upon the most faithful reproduction of the object possible--the artist is
+again and again referred to the study of Nature in order to imitate her.
+Hence, as a general rule, there is less difficulty in the explanation of
+these forms, because even the minute details of the natural object now and
+then offer points that one can fasten upon. It is quite another thing when
+we have to deal with actual decoration which does not aim at anything
+further than at employing the structural laws of organisms in order to
+organize the unwieldy substance, to endow the stone with a higher vitality.
+These latter forms depart, even at the time when they originate, very
+considerably from the natural objects. The successors of the originators
+soon still further modify them by adapting them to particular purposes,
+combining and fusing them with other forms so as to produce particular
+individual forms which have each their own history (_e.g._, the acanthus
+ornament, which, in its developed form, differs very greatly from the
+acanthus plant itself); and in a wider sense we may here enumerate all such
+forms as have been raised by art to the dignity of perfectly viable beings,
+_e.g._, griffins, sphinxes, dragons, and angels.
+
+[Illustration: Fig. 5.]
+
+The deciphering and derivation of such forms as these is naturally
+enough more difficult; in the case of most of them we are not even in
+possession of the most necessary preliminaries to the investigation, and
+in the case of others there are very important links missing (_e.g._,
+for the well-known Greek palmettas). In proportion as the representation
+of the plant was a secondary object, the travesty has been more and more
+complete. As in the case of language, where the root is hardly
+recognizable in the later word, so in decorative art the original form
+is indistinguishable in the ornament. The migration of races and the
+early commercial intercourse between distant lands have done much to
+bring about the fusion of types; but again in contrast to this we find,
+in the case of extensive tracts of country, notably in the Asiatic
+continent, a fixity, throughout centuries, of forms that have once been
+introduced, which occasions a confusion between ancient and modern works
+of art, and renders investigations much more difficult. An old French
+traveler writes: "J'ai vu dans le trésor d'Ispahan les vetements de
+Tamerlan; ils ne different en rien de ceux d'aujourd'hui." Ethnology,
+the natural sciences, and last, but not least, the history of technical
+art are here set face to face with great problems.
+
+[Illustration: FIG. 6.]
+
+In the case in point, the study of the first group of artistic forms that
+have been elaborated by Western art leads to definite results, because the
+execution of the forms in stone can be followed on monuments that are
+relatively not very old, that are dated, and of which the remains are still
+extant. In order to follow the development, I ask your permission to go
+back at once to the very oldest of the known forms. They come down to us
+from the golden era of Greek decorative art--from the fourth or fifth
+century B.C.--when the older simple styles of architecture were supplanted
+by styles characterized by a greater richness of structure and more
+developed ornament. A number of flowers from capitals in Priene, Miletus,
+Eleusis, Athens (monument of Lysicrates), and Pergamon; also flowers from
+the calathos of a Greek caryatid in the Villa Albani near Rome, upon many
+Greek sepulchral wreaths, upon the magnificent gold helmet of a Grecian
+warrior (in the Museum of St. Petersburg)--these show us the simplest type
+of the pattern in question, a folded leaf, that has been bulged out,
+inclosing a knob or a little blossom (see Figs. 3 and 4). This is an
+example from the Temple of Apollo at Miletus, one that was constructed
+about ten years ago, for educational purposes. Here is the specimen of the
+flower of the monument to Lysicrates at Athens, of which the central part
+consists of a small flower or fruits (Figs. 5 and 6).
+
+[Illustration: FIG. 7.]
+
+The form passes over into Roman art. The larger scale of the buildings,
+and the pretensions to a greater richness in details, lead to a further
+splitting up of the leaf into acanthus-like forms. Instead of a fruit-form
+a fir-cone appears, or a pine-apple or other fruit in an almost
+naturalistic form.
+
+In a still larger scale we have the club-shaped knob developing into a
+plant-stem branching off something after the fashion of a candelabrum, and
+the lower part of the leaf, where it is folded together in a somewhat
+bell-shaped fashion, becomes in the true sense of the word a campanulum,
+out of which an absolute vessel-shaped form, as _e.g._ is to be seen in the
+frieze of the Basilica Ulpia in Rome, becomes developed.
+
+[Illustration: FIG. 8.]
+
+Such remains of pictorial representation as are still extant present us
+with an equally perfect series of developments. The splendid Græco-Italian
+vessels, the richly ornamented Apulian vases, show flowers in the spirals
+of the ornaments, and even in the foreground of the pictorial
+representations, which correspond exactly to the above mentioned Greek
+relief representations. [The lecturer sent round, among other
+illustrations, a small photograph of a celebrated vase in Naples
+(representing the funeral rites of Patroclus), in which the flower in
+question appears in the foreground, and is perhaps also employed as
+ornament.] (Figs. 7 and 8.)
+
+The Pompeian paintings and mosaics, and the Roman paintings, of which
+unfortunately very few specimens have come down to us, show that the
+further developments of this form were most manifold, and indeed they form
+in conjunction with the Roman achievements in plastic art the highest point
+that this form reached in its development, a point that the Renaissance,
+which followed hard upon it, did not get beyond.
+
+[Illustration: FIG. 9.]
+
+Thus the work of Raphael from the loggias follows in unbroken succession
+upon the forms from the Thermæ of Titus. It is only afterward that a freer
+handling of the traditional pattern arose, characterized by the
+substitution of, for instance, maple or whitethorn for the acanthus-like
+forms. Often even the central part falls away completely, or is replaced by
+overlapping leaves. In the forms of this century we have the same process
+repeated. Schinkel and Botticher began with the Greek form, and have put it
+to various uses; Stuler, Strack, Gropius, and others followed in their wake
+until the more close resemblance to the forms of the period of the
+Renaissance in regard to Roman art which characterizes the present day was
+attained (Fig. 9).
+
+Now, what plant suggested this almost indispensable form of ornament, which
+ranks along with the acanthus and palmetta, and which has also become so
+important by a certain fusion with the structural laws of both?
+
+[Illustration: FIG. 10.]
+
+We meet with organism of the form in the family of the Araceæ, or aroid
+plants. An enveloping leaf (bract), called the spathe, which is often
+brilliantly colored, surrounds the florets, or fruits, that are disposed
+upon a spadix. Even the older writers--Theophrastus, Dioscorides, Galen,
+and Pliny--devote a considerable amount of attention to several species of
+this interesting family, especially to the value of their swollen stems as
+a food-stuff, to their uses in medicine, etc. Some species of Arum were
+eaten, and even nowadays the value of the swollen stems of some species of
+the family causes them to be cultivated, as, for instance, in Egypt and
+India, etc. (the so-called Portland sago, Portland Island arrowroot, is
+prepared from the swollen stems of _Arum maculatum_). In contrast with the
+smooth or softly undulating outlines of the spathe of Mediterranean Araceæ,
+one species stands out in relief, in which the sharply-marked fold of the
+spathe almost corresponds to the forms of the ornaments which we are
+discussing. It is _Dracunculus vulgaris_, and derives its name from its
+stem, which is spotted like a snake. This plant, which is pretty widely
+distributed in olive woods and in the river valleys of the countries
+bordering on the Mediterranean, was employed to a considerable extent in
+medicine by the ancients (and is so still nowadays, according to Von
+Heldreich, in Greece). It was, besides, the object of particular regard,
+because it was said not only to heal snake-bite, but the mere fact of
+having it about one was supposed to keep away snakes, who were said
+altogether to avoid the places where it grew. But, apart from this, the
+striking appearance of this plant, which often grows to an enormous size,
+would be sufficient to suggest its employment in art. According to
+measurements of Dr. Julius Schmidt, who is not long since dead, and was the
+director of the Observatory at Athens, a number of these plants grow in the
+Valley of Cephisus, and attain a height of as much as two meters, the
+spathe alone measuring nearly one meter. [The lecturer here exhibited a
+drawing (natural size) of this species, drawn to the measurements above
+referred to.]
+
+[Illustration: FIG. 11.]
+
+Dr. Sintenis, the botanist, who last year traveled through Asia Minor and
+Greece, tells me that he saw beautiful specimens of the plant in many
+places, _e.g._, in Assos, in the neighborhood of the Dardanelles, under the
+cypresses of the Turkish cemeteries.
+
+The inflorescence corresponds almost exactly to the ornament, but the
+multipartite leaf has also had a particular influence upon its development
+and upon that of several collateral forms which I cannot now discuss. The
+shape of the leaf accounts for several as yet unexplained extraordinary
+forms in the ancient plane-ornament, and in the Renaissance forms that have
+been thence developed. It first suggested the idea to me of studying the
+plant attentively after having had the opportunity five years ago of seeing
+the leaves in the Botanic Gardens at Pisa. It was only afterward that I
+succeeded in growing some flowers which fully confirmed the expectations
+that I had of them (Figs. 10 and 11).
+
+[Illustration: FIG. 12.]
+
+The leaf in dracunculus has a very peculiar shape; it consists of a number
+of lobes which are disposed upon a stalk which is more or less forked
+(tends more or less to dichotomize). If you call to your minds some of the
+Pompeian wall decorations, you will perceive that similar forms occur there
+in all possible variations. Stems are regularly seen in decorations that
+run perpendicularly, surrounded by leaves of this description. Before this,
+these suggested the idea of a misunderstood (or very conventional)
+perspective representation of a circular flower. Now the form also occurs
+in this fashion, and thus negatives the idea of a perspective
+representation of a closed flower. It is out of this form in combination
+with the flower-form that the series of patterns was developed which we
+have become acquainted with in Roman art, especially in the ornament of
+Titus' Thermæ and in the Renaissance period in Raphael's work. [The
+lecturer here explained a series of illustrations of the ornaments referred
+to (Figs. 12, 13, 14).]
+
+The attempt to determine the course of the first group of forms has been to
+a certain extent successful, but we meet greater difficulties in the study
+of the second.
+
+[Illustration: FIG. 13.]
+
+It is difficult to obtain a firm basis on which to conduct our
+investigations from the historical or geographical point of view into this
+form of art, which was introduced into the West by Arabico-Moorish culture,
+and which has since been further developed here. There is only one method
+open to us in the determination of the form, which is to pass gradually
+from the richly developed and strongly differentiated forms to the smaller
+and simpler ones, even if these latter should have appeared
+contemporaneously or even later than the former. Here we have again to
+refer to the fact that has already been mentioned, to wit, that Oriental
+art remained stationary throughout long periods of time. In point of fact,
+the simpler forms are invariably characterized by a nearer and nearer
+approach to the more ancient patterns and also to the natural flower-forms
+of the Araceæ. We find the spathe, again, sometimes drawn like an acanthus
+leaf, more often, however, bulged out, coming to be more and more of a mere
+outline figure, and becoming converted into a sort of background; then the
+spadix, generally conical in shape, sometimes, however, altogether replaced
+by a perfect thistle, at other times again by a pomegranate. Auberville, in
+his magnificent work "L'Ornement des Tissus," is astonished to find the
+term pomegranate-pattern almost confined to these forms, since their
+central part is generally formed of a thistle-form. As far as I can
+discover in the literature that is at my disposal, this question has not
+had any particular attention devoted to it except in the large work upon
+Ottoman architecture published in Constantinople under the patronage of
+Edhem Pasha. The pomegranate that has served as the original of the pattern
+in question is in this work surrounded with leaves till it gives some sort
+of an approach to the pattern. (There are important suggestions in the book
+as to the employment of melon-forms.) Whoever has picked the fruit from the
+tender twigs of the pomegranate tree, which are close set with small
+altered leaves, will never dream of attributing the derivation of the
+thorny leaves that appear in the pattern to pomegranate leaves at any stage
+of their development.
+
+[Illustration: FIG. 14]
+
+It does not require much penetration to see that the outline of the whole
+form corresponds to the spathe of the Araceæ, even although in later times
+the jagged contour is all that has remained of it, and it appears to have
+been provided with ornamental forms quite independently of the rest of the
+pattern. The inner thistle-form cannot be derived from the common thistle,
+because the surrounding leaves negative any such idea. The artichoke theory
+also has not enough in its favor, although the artichoke, as well as the
+thistle, was probably at a later time directly pressed into service. Prof.
+Ascherson first called my attention to the extremely anciently cultivated
+plant, the safflor (_Carthamus tinctoris_, Fig. 15), a thistle plant whose
+flowers were employed by the ancients as a dye. Some drawings and dried
+specimens, as well as the literature of the subject, first gave me a hope
+to find that this plant was the archetype of this ornament, a hope that was
+borne out by the study of the actual plant, although I was unable to grow
+it to any great perfection.
+
+In the days of the Egyptian King Sargo (according to Ascherson and
+Schweinfurth) this plant was already well known as a plant of cultivation;
+in a wild state it is not known (De Candolle, "Originel des Plantes
+cultivées"). In Asia its cultivation stretches to Japan. Semper cites a
+passage from an Indian drama to the effect that over the doorway there was
+stretched an arch of ivory, and about it were bannerets on which wild
+safran (_Saflor_) was painted.
+
+[Illustration: FIG. 15]
+
+The importance of the plant as a dye began steadily to decrease, and it has
+now ceased to have any value as such in the face of the introduction of
+newer coloring matters (a question that was treated of in a paper read a
+short time ago by Dr. Reimann before this Society). Perhaps its only use
+nowadays is in the preparation of rouge (_rouge végétale_).
+
+But at a time when dyeing, spinning, and weaving were, if not in the one
+hand, yet at any rate intimately connected with one another in the narrow
+circle of a home industry, the appearance of this beautiful gold-yellow
+plant, heaped up in large masses, would be very likely to suggest its
+immortalization in textile art, because the drawing is very faithful to
+nature in regard to the thorny involucre. Drawings from nature of the plant
+in the old botanical works of the sixteenth and seventeenth centuries look
+very like ornamental patterns. Now after the general form had been
+introduced, pomegranates or other fruits--for instance, pine-apples--were
+introduced within the nest of leaves.
+
+[Illustration: FIG. 16.]
+
+Into the detailed study of the intricacies of this subject I cannot here
+enter; the East-Asian influences are not to be neglected, which had
+probably even in early times an effect upon the form that was assumed, and
+have fused the correct style of compound flowers for flat ornament with the
+above-mentioned forms, so as to produce peculiar patterns; we meet them
+often in the so-called Persian textures and flat ornaments (Fig. 16).
+
+We now come to the third group of forms--the so-called Cashmere pattern, or
+Indian palmetta. The developed forms, which, when they have attained their
+highest development, often show us outlines that are merely fanciful, and
+represent quite a bouquet of flowers leaning over to one side, and
+springing from a vessel (the whole corresponding to the Roman form with the
+vessel), must be thrown to one side, while we follow up the simpler forms,
+because in this case also we have no information as to either the where or
+the when the forms originated. (Figs. 17, 18, 19.)
+
+[Illustration: FIG. 17.]
+
+Here again we are struck by resemblances to the forms that were the
+subjects of our previous study, we even come across direct transitional
+forms, which differ from the others only by the lateral curve of the apex
+of the leaf; sometimes it is the central part, the spadix, that is bent
+outward, and the very details show a striking agreement with the structure
+of the aroid inflorescence, so much so that one might regard them as
+actually copied from them.
+
+[Illustration: FIG. 18.]
+
+This form of ornament has been introduced into Europe since the French
+expedition to Egypt, owing to the importation of genuine Cashmere shawls.
+(When it cropped up in isolated forms, as in Venice in the fifteenth
+century, it appears not to have exerted any influence; its introduction is
+perhaps rather to be attributed to calico-printing.) Soon afterward the
+European shawl-manufacture, which is still in a flourishing state, was
+introduced. Falcot informs us that designs of a celebrated French artist,
+Couder, for shawl-patterns, a subject that he studied in India itself, were
+exported back to that country and used there (Fig. 20).
+
+In these shawl-patterns the original simple form meets us in a highly
+developed, magnificent, and splendidly colored differentiation and
+elaboration. This we can have no scruples in ranking along with the
+mediæval plane-patterns, which we have referred to above, among the highest
+achievements of decorative art.
+
+[Illustration: FIG. 19.]
+
+It is evident that it, at any rate in this high stage of development,
+resisted fusion with Western forms of art. It is all the more incumbent
+upon us to investigate the laws of its existence, in order to make it less
+alien to us, or perhaps to assimilate it to ourselves by attaining to an
+understanding of those laws. A great step has been made when criticism has,
+by a more painstaking study, put itself into a position to characterize as
+worthless ignorantly imitated, or even original, miscreations such as are
+eternally cropping up. If we look at our modern manufactures immediately
+after studying patterns which enchant us with their classical repose, or
+after it such others as captivate the eye by their beautiful coloring, or
+the elaborative working out of their details, we recognize that the
+beautifully balanced form is often cut up, choked over with others, or
+mangled (the flower springing up side down from the leaves), the whole
+being traversed at random by spirals, which are utterly foreign to the
+spirit of such a style, and all this at the caprice of uncultured, boorish
+designers. Once we see that the original of the form was a plant, we shall
+ever in the developed, artistic form cling, in a general way at least, to
+the laws of its organization, and we shall at any rate be in a position to
+avoid violent incongruities.
+
+[Illustration: FIG. 20.]
+
+I had resort, a few years ago, to the young botanist Ruhmer, assistant at
+the Botanical Museum at Schöneberg, who has unfortunately since died of
+some chest-disease, in order to get some sort of a groundwork for direct
+investigations. I asked him to look up the literature of the subject, with
+respect to the employment of the Indian Araceæ for domestic uses or in
+medicine. A detailed work on the subject was produced, and establishes
+that, quite irrespective of species of Alocasia and Colocasia that have
+been referred to, a large number of Araceæ were employed for all sorts of
+domestic purposes. Scindapsus, which was used as a medicine, has actually
+retained a Sanskrit name, "vustiva." I cannot here go further into the
+details of this investigation, but must remark that even the incomplete and
+imperfect drawings of these plants, which, owing to the difficulty of
+preserving them, are so difficult to collect through travelers, exhibit
+such a wealth of shape, that it is quite natural that Indian and Persian
+flower-loving artists should be quite taken with them, and employ them
+enthusiastically in decorative art. Let me also mention that Haeckel, in
+his '"Letters of an Indian Traveler," very often bears witness to the
+effect of the Araceæ upon the general appearance of the vegetation, both in
+the full and enormous development of species of Caladia and in the species
+of Pothos which form such impenetrable mazes of interlooping stems.
+
+In conclusion, allow me to remark that the results of my investigation, of
+which but a succinct account has been given here, negative certain
+derivations, which have been believed in, though they have never been
+proved; such as that of the form I have last discussed from the Assyrian
+palmetta, or from a cypress bent down by the wind. To say the least the
+laws of formation here laid down have a more intimate connection with the
+forms as they have come down to us, and give us a better handle for future
+use and development. The object of the investigation was, in general words,
+to prepare for an explanation of the questions raised; and even if the
+results had turned out other than they have, it would have sufficed me to
+have given an impulse to labors which will testify to the truth of the dead
+master's words:
+
+    "Was Du ererbt von deinen Vätern hast,
+    Erwirb es, um es zu besitzen."
+
+       *       *       *       *       *
+
+
+
+
+STEPS TOWARD A KINETIC THEORY OF MATTER.
+
+[Footnote: Meeting of the British Association, Montreal. 1884. Section A.
+Mathematical and Physical science. Opening Address by Prof. Sir William
+Thomson, M.A., LL.D., D.C.L., F.R.SS.L. and E., F.R.A.S., President of the
+Section.]
+
+By Sir WILLIAM THOMSON.
+
+
+The now well known kinetic theory of gases is a step so important in the
+way of explaining seemingly static properties of matter by motion, that it
+is scarcely possible to help anticipating in idea the arrival at a complete
+theory of matter, in which all its properties will be seen to be merely
+attributes of motion. If we are to look for the origin of this idea we must
+go back to Democritus, Epicurus, and Lucretius. We may then, I believe,
+without missing a single step, skip 1800 years. Early last century we find
+in Malebranche's "Recherche de la Verite," the statement that "la durete de
+corps" depends on "petits tourbillons." [1] These words, embedded in a
+hopeless mass of unintelligible statements of the physical, metaphysical,
+and theological philosophies of the day, and unsupported by any
+explanation, elucidation, or illustration throughout the rest of the three
+volumes, and only marred by any other single sentence or word to be found
+in the great book, still do express a distinct conception which forms a
+most remarkable step toward the kinetic theory of matter. A little later we
+have Daniel Bernoulli's promulgation of what we now accept as a surest
+article of scientific faith--the kinetic theory of gases. He, so far as I
+know, thought only of Boyle's and Mariotte's law of the "spring of air," as
+Boyle called it, without reference to change of temperature or the
+augmentation of its pressure if not allowed to expand for elevation of
+temperature, a phenomenon which perhaps he scarcely knew, still less the
+elevation of temperature produced by compression, and the lowering of
+temperature by dilatation, and the consequent necessity of waiting for a
+fraction of a second or a few seconds of time (with apparatus of ordinary
+experimental magnitude), to see a subsidence from a larger change of
+pressure down to the amount of change that verifies Boyle's law. The
+consideration of these phenomena forty years ago by Joule, in connection
+with Bernoulli's original conception, formed the foundation of the kinetic
+theory of gases as we now have it. But what a splendid and useful building
+has been placed on this foundation by Clausius and Maxwell, and what a
+beautiful ornament we see on the top of it in the radiometer of Crookes,
+securely attached to it by the happy discovery of Tait and Dewar,[2] that
+the length of the free path of the residual molecules of air in a good
+modern vacuum may amount to several inches! Clausius' and Maxwell's
+explanations of the diffusion of gases, and of thermal conduction in gases,
+their charmingly intelligible conclusion that in gases the diffusion of
+heat is just a little more rapid than the diffusion of molecules, because
+of the interchange of energy in collisions between molecules,[3] while the
+chief transference of heat is by actual transport of the molecules
+themselves, and Maxwell's explanation of the viscosity of gases, with the
+absolute numerical relations which the work of those two great discoverers
+found among the three properties of diffusion, thermal conduction, and
+viscosity, have annexed to the domain of science a vast and ever growing
+province.
+
+[Footnote 1: "Preuve de la supposition que j'ay faite: Que la matiere
+subtile ou etheree est necessairement composee de PETITS TOURBILLONS; et
+qu'ils sont les causes naturelles de tous les changements qui arrivent a la
+matiere; ce que je confirme par i'explication des effets les plus generaux
+de la Physique, tels que sont la durete des corps, leur fluidite, leur
+pesanteur, legerete, la lumiere et la refraction et reflexion de ses
+rayons."--Malebranche, "Recherche de la Verite," 1712.]
+
+[Footnote 2: Proc. R.S.E., March 2, 1874, and July 5, 1875.]
+
+[Footnote 3: On the other hand, in liquids, on account of the crowdedness
+of the molecules, the diffusion of heat must be chiefly by interchange of
+energies between the molecules, and should be, as experiment proves it is,
+enormously more rapid than the diffusion of the molecules themselves, and
+this again ought to be much less rapid than either the material or thermal
+diffusivities of gases. Thus the diffusivity of common salt through water
+was found by Fick to be as small as 0.0000112 square centimeter per second;
+nearly 200 times as great as this is the diffusivity of heat through water,
+which was found by J.T. Bottomley to be about 0.002 square centimeter per
+second. The material diffusivities of gases, according to Loschmidt's
+experiments, range from 0.98 (the interdiffusivity of carbonic acid and
+nitrous oxide) to 0.642 (the interdiffusivity of carbonic oxide and
+hydrogen), while the thermal diffusivities of gases, calculated according
+to Clausius' and Maxwell's kinetic theory of gases, are 0.089 for carbonic
+acid, 0.16 for common air of other gases of nearly the same density, and
+1.12 for hydrogen (all, both material and thermal, being reckoned in square
+centimeters per second).]
+
+Rich as it is in practical results, the kinetic theory of gases, as
+hitherto developed, stops absolutely short at the atom or molecule, and
+gives not even a suggestion toward explaining the properties in virtue of
+which the atoms or molecules mutually influence one another. For some
+guidance toward a deeper and more comprehensive theory of matter, we may
+look back with advantage to the end of last century and beginning of this
+century, and find Rumford's conclusion regarding the heat generated in
+boring a brass gun: "It appears to me to be extremely difficult, if not
+quite impossible, to form any distinct idea of anything capable of being
+excited and communicated in the manner the heat was excited and
+communicated in these experiments, except it be MOTION;" and Davy's still
+more suggestive statements: "The phenomena of repulsion are not dependent
+on a peculiar elastic fluid for their existence." ... "Heat may be defined
+as a peculiar motion, probably a vibration, of the corpuscles of bodies,
+tending to separate them." ... "To distinguish this motion from others, and
+to signify the causes of our sensations of heat, etc., the name _repulsive_
+motion has been adopted." Here we have a most important idea. It would be
+somewhat a bold figure of speech to say the earth and moon are kept apart
+by a repulsive motion; and yet, after all, what is centrifugal force but a
+repulsive motion, and may it not be that there is no such thing as
+repulsion, and that it is solely by inertia that what seems to be repulsion
+is produced? Two bodies fly together, and, accelerated by mutual
+attraction, if they do not precisely hit one another, they cannot but
+separate in virtue of the inertia of their masses. So, after dashing past
+one another in sharply concave curves round their common center of gravity,
+they fly asunder again. A careless onlooker might imagine they had repelled
+one another, and might not notice the difference between what he actually
+sees and what he would see if the two bodies had been projected with great
+velocity toward one another, and either colliding and rebounding, or
+repelling one another into sharply convex continuous curves, fly asunder
+again.
+
+Joule, Clausius, and Maxwell, and no doubt Daniel Bernoulli himself, and I
+believe every one who has hitherto written or done anything very explicit
+in the kinetic theory of gases, has taken the mutual action of molecules in
+collision as repulsive. May it not after all be attractive? This idea has
+never left my mind since I first read Davy's "Repulsive Motion," about
+thirty-five years ago, and I never made anything of it, at all events have
+not done so until to-day (June 16, 1884)--if this can be said to be making
+anything of it--when, in endeavoring to prepare the present address, I
+notice that Joule's and my own old experiments[1] on the thermal effect of
+gases expanding from a high-pressure vessel through a porous plug, proves
+the less dense gas to have greater intrinsic _potential_ energy than the
+denser gas, if we assume the ordinary hypothesis regarding the temperature
+of a gas, according to which two gases are of equal temperatures [2] when
+the kinetic energies of their constituent molecules are of equal average
+amounts per molecule.
+
+[Footnote 1: Republished in Sir W. Thomson's "Mathematical and Physical
+Papers," vol. i., article xlix., p. 381. ]
+
+[Footnote 2: That this is a mere hypothesis has been scarcely remarked by
+the founders themselves, nor by almost any writer on the kinetic theory of
+gases. No one has yet examined the question, What is the condition as
+regards average distribution of kinetic energy, which is ultimately
+fulfilled by two portions of gaseous matter, separated by a thin elastic
+septum which absolutely prevents interdiffusion of matter, while it allows
+interchange of kinetic energy by collisions against itself? Indeed, I do
+not know but, that the present is the very first statement which has ever
+been published of this condition of the problem of equal temperatures
+between two gaseous masses.]
+
+Think of the thing thus. Imagine a great multitude of particles inclosed by
+a boundary which may be pushed inward in any part all round at pleasure.
+Now station an engineer corps of Maxwell's army of sorting demons all round
+the inclosure, with orders to push in the boundary diligently everywhere,
+when none of the besieged troops are near, and to do nothing when any of
+them are seen approaching, and until after they have turned again inward.
+The result will be that, with exactly the same sum of kinetic and potential
+energies of the same inclosed multitude of particles, the throng has been
+caused to be denser. Now Joule's and my own old experiments on the efflux
+of air prove that if the crowd be common air, or oxygen, or nitrogen, or
+carbonic acid, the temperature is a little higher in the denser than in the
+rarer condition when the energies are the same. By the hypothesis, equality
+of temperature between two different gases or two portions of the same gas
+at different densities means equality of kinetic energies in the same
+number of molecules of the two. From our observations proving the
+temperature to be higher, it therefore follows that the potential energy is
+smaller in the condensed crowd. This--always, however, under protest as to
+the temperature hypothesis--proves some degree of attraction among the
+molecules, but it does not prove ultimate attraction between two molecules
+in collision, or at distances much less than the average mutual distance of
+nearest neighbors in the multitude. The collisional force might be
+repulsive, as generally supposed hitherto, and yet attraction might
+predominate in the whole reckoning of difference between the intrinsic
+potential energies of the more dense and less dense multitudes.
+
+It is however remarkable that the explanation of the propagation of sound
+through gases, and even of the positive fluid pressure of a gas against the
+sides of the containing vessel, according to the kinetic theory of gases,
+is quite independent of the question whether the ultimate collisional force
+is attractive or repulsive. Of course it must be understood that, if it is
+attractive, the particles must, be so small that they hardly ever
+meet--they would have to be infinitely small to _never_ meet--that, in
+fact, they meet so seldom, in comparison with the number of times their
+courses--are turned through large angles by attraction, that the influence
+of these surely attractive collisions is preponderant over that of the
+comparatively very rare impacts from actual contact. Thus, after all, the
+train of speculation suggested by Davy's "Repulsive Motion" does not allow
+us to escape from the idea of true repulsion, does not do more than let us
+say it is of no consequence, nor even say this with truth, because, if
+there are impacts at all, the nature of the force during the impact and the
+effects of the mutual impacts, however rare, cannot be evaded in any
+attempt to realize a conception of the kinetic theory of gases. And in
+fact, unless we are satisfied to imagine the atoms of a gas as mathematical
+points endowed with inertia, and as, according to Boscovich, endowed with
+forces of mutual, positive, and negative attraction, varying according to
+some definite function of the distance, we cannot avoid the question of
+impacts, and of vibrations and rotations of the molecules resulting from
+impacts, and we must look distinctly on each molecule as being either a
+little elastic solid or a configuration of motion in a continuous
+all-pervading liquid. I do not myself see how we can ever permanently rest
+anywhere short of this last view; but it would be a very pleasant temporary
+resting-place on the way to it if we could, as it were, make a mechanical
+model of a gas out of little pieces of round, perfectly elastic solid
+matter, flying about through the space occupied by the gas, and colliding
+with one another and against the sides of the containing vessel.
+
+This is, in fact, all we have of the kinetic theory of gases up to the
+present time, and this has done for us, in the hands of Clausius and
+Maxwell, the great things which constitute our first step toward a
+molecular theory of matter. Of course from it we should have to go on to
+find an explanation of the elasticity and all the other properties of the
+molecules themselves, a subject vastly more complex and difficult than the
+gaseous properties, for the explanation of which we assume the elastic
+molecule; but without any explanation of the properties of the molecule
+itself, with merely the assumption that the molecule has the requisite
+properties, we might rest happy for a while in the contemplation of the
+kinetic theory of gases, and its explanation of the gaseous properties,
+which is not only stupendously important as a step toward a more
+thoroughgoing theory of matter, but is undoubtedly the expression of a
+perfectly intelligible and definite set of facts in Nature.
+
+But alas for our mechanical model consisting of the cloud of little elastic
+solids flying about among one another. Though each particle have absolutely
+perfect elasticity, the end must be pretty much the same as if it were but
+imperfectly elastic. The average effect of repeated and repeated mutual
+collisions must be to gradually convert all the translational energy into
+energy of shriller and shriller vibrations of the molecule. It seems
+certain that each collision must have something more of energy in
+vibrations of very finely divided nodal parts than there was of energy in
+such vibrations before the impact. The more minute this nodal subdivision,
+the less must be the tendency to give up part of the vibrational energy
+into the shape of translational energy in the course of a collision; and I
+think it is rigorously demonstrable that the whole translational energy
+must ultimately become transformed into vibrational energy of higher and
+higher nodal subdivisions if each molecule is a continuous elastic solid.
+Let us, then, leave the kinetic theory of gases for a time with this
+difficulty unsolved, in the hope that we or others after us may return to
+it, armed with more knowledge of the properties of matter, and with sharper
+mathematical weapons to cut through the barrier which at present hides from
+us any view of the molecule itself, and of the effects other than mere
+change of translational motion which it experiences in collision.
+
+To explain the elasticity of a gas was the primary object of the kinetic
+theory of gases. This object is only attainable by the assumption of an
+elasticity more complex in character, and more difficult of explanation,
+than the elasticity of gases--the elasticity of a solid. Thus, even if the
+fatal fault in the theory, to which I have alluded, did not exist, and if
+we could be perfectly satisfied with the kinetic theory of gases founded on
+the collisions of elastic solid molecules, there would still be beyond it a
+grander theory which need not be considered a chimerical object of
+scientific ambition--to explain the elasticity of solids. But we may be
+stopped when we commence to look in the direction of such a theory with the
+cynical question, What do you mean by explaining a property of matter? As
+to being stopped by any such question, all I can say is that if engineering
+were to be all and to end all physical science, we should perforce be
+content with merely finding properties of matter by observation, and using
+them for practical purposes. But I am sure very few, if any, engineers are
+practically satisfied with so narrow a view of their noble profession. They
+must and do patiently observe, and discover by observation, properties of
+matter and results of material combinations. But deeper questions are
+always present, and always fraught with interest to the true engineer, and
+he will be the last to give weight to any other objection to any attempt to
+see below the surface of things than the practical question, Is it likely
+to prove wholly futile? But now, instead of imagining the question, What do
+you mean by explaining a property of matter? to be put cynically, and
+letting ourselves be irritated by it, suppose we give to the questioner
+credit for being sympathetic, and condescend to try and answer his
+question. We find it not very easy to do so. All the properties of matter
+are so connected that we can scarcely imagine one _thoroughly explained_
+without our seeing its relation to all the others, without in fact having
+the explanation of all; and till we have this we cannot tell what we mean
+by "explaining a property" or "explaining the properties" of matter. But
+though this consummation may never be reached by man, the progress of
+science may be, I believe will be, step by step toward it, on many
+different roads converging toward it from all sides. The kinetic theory of
+gases is, as I have said, a true step on one of the roads. On the very
+distinct road of chemical science, St. Claire Deville arrived at his grand
+theory of dissociation without the slightest aid from the kinetic theory of
+gases. The fact that he worked it out solely from chemical observation and
+experiment, and expounded it to the world without any hypothesis whatever,
+and seemingly even without consciousness of the beautiful explanation it
+has in the kinetic theory of gases, secured for it immediately an
+independent solidity and importance as a chemical theory when he first
+promulgated it, to which it might even by this time scarcely have attained
+if it had first been suggested as a probability indicated by the kinetic
+theory of gases, and been only afterward confirmed by observation. Now,
+however, guided by the views which Clausius and Williamson have given us of
+the continuous interchange of partners between the compound molecules
+constituting chemical compounds in the gaseous state, we see in Deville's
+theory of dissociation a point of contact of the most transcendent interest
+between the chemical and physical lines of scientific progress.
+
+To return to elasticity: if we could make out of matter devoid of
+elasticity a combined system of relatively moving parts which, in virtue of
+motion, has the essential characteristics of an elastic body, this would
+surely be, if not positively a step in the kinetic theory of matter, at
+least a fingerpost pointing a way which we may hope will lead to a kinetic
+theory of matter. Now this, as I have already shown,[1] we can do in
+several ways. In the case of the last of the communications referred to, of
+which only the title has hitherto been published, I showed that, from the
+mathematical investigation of a gyrostatically dominated combination
+contained in the passage of Thomson and Tait's "Natural Philosophy"
+referred to, it follows that any ideal system of material particles, acting
+on one another mutually through massless connecting springs, may be
+perfectly imitated in a model consisting of rigid links jointed together,
+and having rapidly rotating fly wheels pivoted on some or on all of the
+links. The imitation is not confined to cases of equilibrium. It holds also
+for vibration produced by disturbing the system infinitesimally from a
+position of stable equilibrium and leaving it to itself. Thus we may make a
+gyrostatic system such that it is in equilibrium under the influence of
+certain positive forces applied to different points of this system; all the
+forces being precisely the same as, and the points of application similarly
+situated to, those of the stable system with springs. Then, provided proper
+masses (that is to say, proper amounts and distributions of inertia) be
+attributed to the links, we may remove the external forces from each
+system, and the consequent vibration of the points of application of the
+forces will be identical. Or we may act upon the systems of material points
+and springs with any given forces for any given time, and leave it to
+itself, and do the same thing for the gyrostatic system; the consequent
+motion will be the same in the two cases. If in the one case the springs
+are made more and more stiff, and in the other case the angular velocities
+of the fly wheels are made greater and greater, the periods of the
+vibrational constituents of the motion will become shorter and shorter, and
+the amplitudes smaller and smaller, and the motions will approach more and
+more nearly those of two perfectly rigid groups of material points moving
+through space and rotating according to the well known mode of rotation of
+a rigid body having unequal moments of inertia about its three principal
+axes. In one case the ideal nearly rigid connection between the particles
+is produced by massless, exceedingly stiff springs; in the other case it is
+produced by the exceedingly rapid rotation of the fly wheels in a system
+which, when the fly wheels are deprived of their rotation, is perfectly
+limp.
+
+[Footnote 1: Paper on "Vortex Atoms," _Proc_. R.S.E. February. 1867:
+abstract of a lecture before the Royal Institution of Great Britain, March
+4, 1881, on "Elasticity Viewed as possibly a Mode of Motion"; Thomson and
+Tait's "Natural Philosophy," second edition, part 1, §§ 345 viii. to 345
+xxxvii.; "On Oscillation and Waves in an Adynamic Gyrostatic System" (title
+only), _Proc_. R.S.E. March, 1883.]
+
+The drawings (Figs. 1 and 2) before you illustrate two such material
+systems.[1] The directions of rotation of the fly-wheels in the gyrostatic
+system (Fig. 2) are indicated by directional ellipses, which show in
+perspective the direction of rotation of the fly-wheel of each gyrostat.
+The gyrostatic system (Fig. 2) might have been constituted of two
+gyrostatic members, but four are shown for symmetry. The inclosing circle
+represents in each case in section an inclosing spherical shell to prevent
+the interior from being seen. In the inside of one there are fly-wheels, in
+the inside of the other a massless spring. The projecting hooked rods seem
+as if they are connected by a spring in each case. If we hang any one of
+the systems up by the hook on one of its projecting rods, and hang a weight
+to the hook of the other projecting rod, the weight, when first put on,
+will oscillate up and down, and will go on doing so for ever if the system
+be absolutely unfrictional. If we check the vibration by hand, the weight
+will hang down at rest, the pin drawn out to a certain degree; and the
+distance drawn out will be simply proportional to the weight hung on, as in
+an ordinary spring balance.
+
+[Footnote 1: In Fig. 1 the two hooked rods seen projecting from the sphere
+are connected by an elastic coach-spring. In Fig. 2 the hooked rods are
+connected one to each of two opposite corners of a four-sided jointed
+frame, each member of which carries a gyrostat so that the axis of rotation
+of the fly-wheel is in the axis of the member of the frame which bears it.
+Each of the hooked rods in Fig. 2 is connected to the framework through a
+swivel joint, so that the whole gyrostatic framework may be rotated about
+the axis of the hooked rods in order to annul the moment of momentum of the
+framework about this axis due to rotation of the fly-wheels in the
+gyrostat.]
+
+[Illustration: FIG. 1]
+
+[Illustration: FIG. 2]
+
+Here, then, out of matter possessing rigidity, but absolutely devoid of
+elasticity, we have made a perfect model of a spring in the form of a
+spring balance. Connect millions of millions of particles by pairs of rods
+such as these of this spring balance, and we have a group of particles
+constituting an elastic solid; exactly fulfilling the mathematical ideal
+worked out by Navier, Poisson, and Cauchy, and many other mathematicians,
+who, following their example, have endeavored to found a theory of the
+elasticity of solids on mutual attraction and repulsion between a group of
+material particles. All that can possibly be done by this theory, with its
+assumption of forces acting according to any assumed law of relation to
+distance, is done by the gyrostatic system. But the gyrostatic system does,
+besides, what the system of naturally acting material particles cannot
+do--it constitutes an elastic solid which can have the Faraday
+magneto-optic rotation of the plane of polarization of light; supposing the
+application of our solid to be a model of the luminiferous ether for
+illustrating the undulatory theory of light. The gyrostatic model spring
+balance is arranged to have zero moment of momentum as a whole, and
+therefore to contribute nothing to the Faraday rotation; with this
+arrangement the model illustrates the luminiferous ether in a field
+unaffected by magnetic force. But now let there be a different rotational
+velocity imparted to the jointed square round the axis of the two
+projecting hooked rods, such as to give a resultant moment of momentum
+round any given line through the center of inertia of the system; and let
+pairs of the hooked rods in the model thus altered, which is no longer a
+model of a mere spring balance, be applied as connections between millions
+of pairs of particles as before, with the lines of resultant moment of
+momentum all similarly directed. We now have a model elastic solid which
+will have the property that the direction of vibration in waves of
+rectilinear vibrations propagated through it shall turn round the line of
+propagation of the waves, just as Faraday's observation proves to be done
+by the line of vibration of light in a dense medium between the poles of a
+powerful magnet. The case of wave front perpendicular to the lines of
+resultant moment of momentum (that is to say, the direction of propagation
+being parallel to these lines) corresponds, in our mechanical model, to the
+case of light traveling in the direction of the lines of force in a
+magnetic field.
+
+In these illustrations and models we have different portions of ideal rigid
+matter acting upon one another, by normal pressure at mathematical points
+of contact--of course no forces of friction are supposed. It is exceedingly
+interesting to see how thus, with no other postulates than inertia,
+rigidity, and mutual impenetrability, we can thoroughly model not only an
+elastic solid, and any combination of elastic solids, but so complex and
+recondite a phenomenon as the passage of polarized light through a magnetic
+field. But now, with the view of ultimately discarding the postulate of
+rigidity from all our materials, let us suppose some to be absolutely
+destitute of rigidity, and to possess merely inertia and incompressibility,
+and mutual impenetrability with reference to the still remaining rigid
+matter. With these postulates we can produce a perfect model of mutual
+action at a distance between solid particles, fulfilling the condition, so
+keenly desired by Newton and Faraday, of being explained by continuous
+action through an intervening medium. The law of the mutual force in our
+model, however, is not the simple Newtonian law, but the much more complex
+law of the mutual action between electro magnets--with this difference,
+that in the hydro-kinetic model in every case the force is opposite in
+direction to the corresponding force in the electro-magnetic analogue.
+Imagine a solid bored through with a hole, and placed in our ideal perfect
+liquid. For a moment let the hole be stopped by a diaphragm, and let an
+impulsure pressure be applied for an instant uniformly over the whole
+membrane, and then instantly let the membrane be dissolved into liquid.
+This action originates a motion of the liquid relatively to the solid, of a
+kind to which I have given the name of "irrotational circulation," which
+remains absolutely constant however the solid be moved through the liquid.
+Thus, at any time the actual motion of the liquid at any point in the
+neighborhood of the solid will be the resultant of the motion it would have
+in virtue of the circulation alone, were the solid at rest, and the motion
+it would have in virtue of the motion of the solid itself, had there been
+no circulation established through the aperture. It is interesting and
+important to remark in passing that the whole kinetic energy of the liquid
+is the sum of the kinetic energies which it would have in the two cases
+separately. Now, imagine the whole liquid to be inclosed in an infinitely
+large, rigid, containing vessel, and in the liquid, at an infinite distance
+from any part of the containing vessel, let two perforated solids, with
+irrotational circulation through each, be placed at rest near one another.
+The resultant fluid motion due to the two circulations, will give rise to
+fluid pressure on the two bodies, which, if unbalanced, will cause them to
+move. The force systems--force-and-torques, or pairs of forces--required to
+prevent them from moving will be mutual and opposite, and will be the same
+as, but opposite in direction to, the mutual force systems required to hold
+at rest two electromagnets fulfilling the following specification: The two
+electro magnets are to be of the same shape and size as the two bodies, and
+to be placed in the same relative positions, and to consist of infinitely
+thin layers of electric currents in the surfaces of solids possessing
+extreme diamagnetic quality--in other words, infinitely small permeability.
+The distribution of electric current on each body may be any whatever which
+fulfills the condition that the total current across any closed line drawn
+on the surface once through the aperture is equal to ¼ [pi] of the
+circulation[1] through the aperture in the hydro-kinetic analogue.
+
+[Footnote 1: The integral of tangential component velocity all round any
+closed curve, passing once through the aperture, is defined as the
+"cyclic-constant" or the "circulation" ("Vortex Motion," § 60 (a), _Trans_.
+R.S.E., April 29, 1867). It has the same value for all closed curves
+passing just once through the aperture, and it remains constant through all
+time, whether the solid body be in motion or at rest.]
+
+It might be imagined that the action at a distance thus provided for by
+fluid motion could serve as a foundation for a theory of the equilibrium,
+and the vibrations, of elastic solids, and the transmission of waves like
+those of light through an extended quasi-elastic solid medium. But
+unfortunately for this idea the equilibrium is essentially unstable, both
+in the case of magnets and, notwithstanding the fact that the forces are
+oppositely directed, in the hydro-kinetic analogue also, when the several
+movable bodies (two or any greater number) are so placed relatively as to
+be in equilibrium. If, however, we connect the perforated bodies with
+circulation through them in the hydro-kinetic system, by jointed rigid
+connecting links, we may arrange for configurations of stable equilibrium.
+Thus, without fly-wheels, but with fluid circulations through apertures, we
+may make a model spring balance or a model luminiferous ether, either
+without or with the rotational quality corresponding to that of the true
+luminiferous ether in the magnetic fluid--in short, do all by the
+perforated solids with circulations through them that we saw we could do by
+means of linked gyrostats. But something that we cannot do by linked
+gyrostats we can do by the perforated bodies with fluid circulation: we can
+make a model gas. The mutual action at a distance, repulsive or attractive
+according to the mutual aspect of the two bodies when passing within
+collisional distance[1] of one another, suffices to produce the change of
+direction of motion in collision, which essentially constitutes the
+foundation of the kinetic theory of gases, and which, as we have seen
+before, may as well be due to attraction as to repulsion, so far as we know
+from any investigation hitherto made in this theory.
+
+[Footnote 1: According to this view, there is no precise distance, or
+definite condition respecting the distance, between two molecules, at which
+apparently they come to be in collision, or when receding from one another
+they cease to be in collision. It is convenient, however, in the kinetic
+theory of gases, to adopt arbitrarily a precise definition of collision,
+according to which two bodies or particles mutually acting at a distance
+may be said to be in collision when their mutual action exceeds some
+definite arbitrarily assigned limit, as, for example, when the radius of
+curvature of the path of either body is less than a stated fraction (one
+one-hundredth, for instance) of the distance between them.]
+
+There remains, however, as we have seen before, the difficulty of providing
+for the case of actual impacts between the solids, which must be done by
+giving them massless spring buffers or, which amounts to the same thing,
+attributing to them repulsive forces sufficiently powerful at very short
+distances to absolutely prevent impacts between solid and solid; unless we
+adopt the equally repugnant idea of infinitely small perforated solids,
+with infinitely great fluid circulations through them. Were it not for this
+fundamental difficulty, the hydro-kinetic model gas would be exceedingly
+interesting; and, though we could scarcely adopt it as conceivably a true
+representation of what gases really are, it might still have some
+importance as a model configuration of solid and liquid matter, by which
+without elasticity the elasticity of true gas might be represented.
+
+But lastly, since the hydro-kinetic model gas with perforated solids and
+fluid circulations through them fails because of the impacts between the
+solids, let us annul the solids and leave the liquid performing
+irrotational circulation round vacancy,[1] in the place of the solid cores
+which we have hitherto supposed; or let us annul the rigidity of the solid
+cores of the rings, and give them molecular rotation according to
+Helmholtz's theory of vortex motion. For stability the molecular rotation
+must be such as to give the same velocity at the boundary of the rotational
+fluid core as that of the irrotationally circulating liquid in contact with
+it, because, as I have proved, frictional slip between two portions of
+liquid in contact is inconsistent with stability. There is a further
+condition, upon which I cannot enter into detail just now, but which may be
+understood in a general way when I say that it is a condition of either
+uniform or of increasing molecular rotation from the surface inward,
+analogous to the condition that the density of a liquid, resting for
+example under the influence of gravity, must either be uniform or must be
+greater below than above for stability of equilibrium. All that I have said
+in favor of the model vortex gas composed of perforated solids with fluid
+circulations through them holds without modification for the purely
+hydro-kinetic model, composed of either Helmholtz cored vortex rings or of
+coreless vortices, and we are now troubled with no such difficulty as that
+of the impacts between solids. Whether, however, when the vortex theory of
+gases is thoroughly worked out, it will or will not be found to fail in a
+manner analogous to the failure which I have already pointed out in
+connection with the kinetic theory of gases composed of little elastic
+solid molecules, I cannot at present undertake to speak with certainty. It
+seems to me most probable that the vortex theory cannot fail in any such
+way, because all I have been able to find out hitherto regarding the
+vibration of vortices,[2] whether cored or coreless, does not seem to imply
+the liability of translational or impulsive energies of the individual
+vortices becoming lost in energy of smaller and smaller vibrations.
+
+[Footnote 1: Investigations respecting coreless vortices will be found in a
+paper by the author, "Vibrations of a Columnar Vortex," _Proc_. R.S.E.,
+March 1, 1880; and a paper by Hicks, recently read before the Royal
+Society.]
+
+[Footnote 2: See papers by the author "On Vortex Motion." _Trans_. R.S.E.
+April, 1867, and "Vortex Statics," _Proc_. R.S.E. December, 1875; also a
+paper by J.J. Thomson, B.A., "On the Vibrations of a Vortex Ring," _Trans_.
+R.S. December, 1881, and his valuable book on "Vortex Motion."]
+
+As a step toward kinetic theory of matter, it is certainly most interesting
+to remark that in the quasi-elasticity, elasticity looking like that of an
+India-rubber band, which we see in a vibrating smoke-ring launched from an
+elliptic aperture, or in two smoke-rings which were circular, but which
+have become deformed from circularity by mutual collision, we have in
+reality a virtual elasticity in matter devoid of elasticity, and even
+devoid of rigidity, the virtual elasticity being due to motion, and
+generated by the generation of motion.
+
+       *       *       *       *       *
+
+
+
+
+APPLICATION OF ELECTRICITY TO TRAMWAYS.
+
+By M. HOLROYD SMITH.
+
+
+Last year, when I had the pleasure of reading a paper before you on my new
+system of electric tramways, I ventured to express the hope that before
+twelve months had passed, "to be able to report progress," and I am happy
+to say that notwithstanding the wearisome delay and time lost in fruitless
+negotiations, and the hundred and one difficulties within and without that
+have beset me, I am able to appear before you again and tell you of
+advance.
+
+[Illustration: FIG. 1]
+
+Practical men know well that there is a wide difference between a model and
+a full sized machine; and when I decided to construct a full sized tramcar
+and lay out a full sized track, I found it necessary to make many
+alterations of detail, my chief difficulty being so to design my work as to
+facilitate construction and allow of compensation for that inaccuracy of
+workmanship which I have come to regard as inevitable.
+
+In order to satisfy the directors of a tramway company of the practical
+nature of my system before disturbing their lines, I have laid, in a field
+near the works of Messrs. Smith, Baker & Co., Manchester, a track 110 yards
+long, 4 ft. 8½ in. gauge, and I have constructed a full sized street
+tramcar to run thereon. My negotiations being with a company in a town
+where there are no steep gradients, and where the coefficient of friction
+of ordinary wheels would be sufficient for all tractive purposes, I thought
+it better to avoid the complication involved in employing a large central
+wheel with a broad surface specially designed for hilly districts, and with
+which I had mounted a gradient of one in sixteen.
+
+[Illustration: FIG. 2]
+
+But as the line in question was laid with all the curves unnecessarily
+quick, even those in the "pass-bies," I thought it expedient to employ
+differential gear, as illustrated at D, Fig. 1, which is a sketch plan
+showing the mechanism employed. M is a Siemens electric motor running at
+650 revolutions per minute; E is a combination of box gearing, frictional
+clutch, and chain pinion, and from this pinion a steel chain passes around
+the chain-wheel, H, which is free to revolve upon the axle, and carries
+within it the differential pinion, gearing with the bevel-wheel, B², keyed
+upon the sleeve of the loose tram-wheel, T², and with the bevel-wheel, B¹,
+keyed upon the axle, to which the other tram-wheel, T¹, is attached. To the
+other tram-wheels no gear is connected; one of them is fast to the axle,
+and the other runs loose, but to them the brake is applied in the usual
+manner.
+
+The electric current from the collector passes, by means of a copper wire,
+and a switch upon the dashboard of the car, and resistance coils placed
+under the seats, to the motor, and from the motor by means of an adjustable
+clip (illustrated in diagram, Fig. 2) to the axles, and by them through the
+four wheels to the rails, which form the return circuit.
+
+[Illustration: FIG. 3]
+
+I have designed many modifications of the track, but it is, perhaps, best
+at present to describe only that which I have in actual use, and it is
+illustrated in diagram, Fig. 3, which is a sectional and perspective view
+of the central channel. L is the surface of the road, and SS are the
+sleepers, CC are the chairs which hold the angle iron, AA forming the
+longitudinally slotted center rail and the electric lead, which consists of
+two half-tubes of copper insulated from the chairs by the blocks, I, I. A
+special brass clamp, free to slide upon the tube, is employed for this
+purpose, and the same form of clamp serves to join the two ends of the
+copper tubes together and to make electric contact. Two half-tubes instead
+of one slotted tube have been employed, in order to leave a free passage
+for dirt or wet to fall through the slot in the center rail to the drain
+space, G. Between chair and chair hewn granite or artificial stone is
+employed, formed, as shown in the drawing, to complete the surface of the
+road and to form a continuous channel or drain. In order that this drain
+may not become choked, at suitable intervals, in the length of the track,
+sump holes are formed as illustrated in diagram, Fig. 4 These sump holes
+have a well for the accumulation of mud, and are also connected with the
+main street drain, so that water can freely pass away. The hand holes
+afford facility for easily removing the dirt.
+
+In a complete track these hand holes would occasionally be wider than shown
+here, for the purpose of removing or fixing the collector, Fig. 5, which
+consists of two sets of spirally fluted rollers free to revolve upon
+spindles, which are held by knuckle-joints drawn together by spiral
+springs; by this means the pressure of the rollers against the inside of
+the tube is constantly maintained, and should any obstruction occur in the
+tube the spiral flute causes it to revolve, thus automatically cleansing
+the tubes.
+
+[Illustration: FIG. 4]
+
+The collector is provided with two steel plates, which pass through the
+slit in the center rail; the lower ends of these plates are clamped by the
+upper frame of the collector, insulating material being interposed, and the
+upper ends are held in two iron cheeks. Between these steel plates
+insulated copper strips are held, electrically connected with the collector
+and with the adjustable clip mounted upon the iron cheeks; this clip holds
+the terminal on the end of the wire (leading to the motor) firmly enough
+for use, the cheeks being also provided with studs for the attachment of
+leather straps hooked on to the framework of the car, one for the forward
+and one for backward movement of the collector. These straps are strong
+enough for the ordinary haulage of the collector, and for the removal of
+pebbles and dirt that may get into the slit; but should any absolute block
+occur then they break and the terminal is withdrawn from the clip; the
+electric contact being thereby broken the car stops, the obstruction can
+then be removed and the collector reconnected without damage and with
+little delay.
+
+[Illustration: FIG. 5]
+
+In order to secure continuity of the center rail throughout the length of
+the track, and still provide for the removal of the collector at frequent
+intervals, the framework of the collector is so made that, by slackening
+the side-bolts, the steel plates can be drawn upward and the collector
+itself withdrawn sideways through the hand holes, one of the half-tubes
+being removed for the purpose.
+
+Fig. 6 illustrates another arrangement that I have constructed, both of
+collector and method of collecting.
+
+[Illustration: FIG. 6]
+
+As before mentioned, the arrangement now described has been carried out in
+a field near the works of Messrs. Smith, Baker & Co., Cornbrook Telegraph
+Works, Manchester, and its working efficiency has been most satisfactory.
+After a week of rain and during drenching showers the car ran with the same
+speed and under the same control as when the ground was dry.
+
+This I account for by the theory that when the rails are wet and the tubes
+moist the better contact made compensates for the slight leakage that may
+occur.
+
+At the commencement of my paper I promised to confine myself to work done;
+I therefore abstain from describing various modifications of detail for the
+same purpose. But one method of supporting and insulating the conductor in
+the channel may be suggested by an illustration of the plan I adopted for a
+little pleasure line in the Winter Gardens, Blackpool.
+
+[Illustration: FIG. 7.]
+
+Fig. 7. There the track being exclusively for the electric railway, it was
+not necessary to provide a center channel; the conductor has therefore been
+placed in the center of the track, and consists of bar iron 1¼ in. by ½
+in., and is held vertically by means of studs riveted into the side; these
+studs pass through porcelain insulators, and by means of wooden clamps and
+wedges are held in the iron chairs which rest upon the sleepers. The iron
+conductors were placed vertically to facilitate bending round the sharp
+curves which were unavoidable on this line.
+
+The collector consists of two metal slippers held together by springs,
+attached to the car by straps and electrically connected to the motor by
+clips in the same manner as the one employed in Manchester.
+
+I am glad to say that, notwithstanding the curves with a radius of 55 feet
+and gradients of 1 in 57, this line is also a practical success.
+
+       *       *       *       *       *
+
+
+
+
+FIRES IN LONDON AND NEW YORK.
+
+
+When the chief of the London Fire Brigade visited the United States in
+1882, he was, as is the general rule on the other side of the Atlantic,
+"interviewed"--a custom, it may be remarked, which appears to be gaining
+ground also in this country. The inferences drawn from these interviews
+seem to be that the absence of large fires in London was chiefly due to the
+superiority of our fire brigade, and that the greater frequency of
+conflagrations in American cities, and particularly in New York, was due to
+the inferiority of their fire departments. How unjust such a comparison
+would be is shown in a paper presented by Mr. Edward B. Dorsey, a member
+of the American Society of Civil Engineers, to that association, in which
+the author discusses the comparative liability to and danger from
+conflagrations in London and in American cities. He found from an
+investigation which he conducted with much care during a visit to London
+that it is undoubtedly true that large fires are much less frequent in the
+metropolis than in American cities; but it is equally true that the
+circumstances existing in London and New York are quite different. As it is
+a well-known fact that the promptness, efficiency, and bravery of American
+firemen cannot be surpassed, we gladly give prominence to the result of the
+author's investigations into the true causes of the great liability of
+American cities to large fires. In a highly interesting comparison the
+writer has selected New York and London as typical cities, although his
+observations will apply to most American and English towns, if, perhaps,
+with not quite the same force. In the first place, the efforts of the
+London Fire Brigade receive much aid from our peculiarly damp climate. From
+the average of eleven years (1871-1881) of the meteorological observations
+made at the Greenwich Observatory, it appears that in London it rains, on
+the average, more than three days in the week, that the sun shines only
+one-fourth of the time he is above the horizon, and that the atmosphere
+only lacks 18 per cent. of complete saturation, and is cloudy seven-tenths
+of the time. Moreover, the humidity of the atmosphere in London is very
+uniform, varying but little in the different months. Under these
+circumstances, wood will not be ignited very easily by sparks or by contact
+with a weak flame. This is very different from the condition of wood in the
+long, hot, dry seasons of the American continent. The average temperature
+for the three winter months in London is 38.24 degrees Fahr.; in New York
+it is 31.56 degrees, or 6.68 degrees lower. This lower range of temperature
+must be the cause of many conflagrations, for, to make up for the
+deficiency in the natural temperature, there must be in New York many more
+and larger domestic fires. The following statistics, taken from the records
+of the New York Fire Department, show this. In the three winter months of
+1881, January, February, and December, there were 522 fire alarms in New
+York, or an average per month of 174; in the remaining nine months 1,263,
+or an average per month of 140. In the corresponding three winter months of
+1882 there were 602 fire alarms, or an average per month of 201; in the
+remaining nine months 1,401, or an average per month of 155. In round
+numbers there were in 1881 one-fourth, and in 1882 one-third more fire
+alarms in the three winter months than in the nine warmer months. We are
+not aware that similar statistics have ever been compiled for London, and
+are consequently unable to draw comparison; but, speaking from
+recollection, fires appear to be more frequent also in London during the
+winter months.
+
+Another cause of the greater frequency of fires in New York and their more
+destructive nature is the greater density of population in that city. The
+London Metropolitan Police District covers 690 square miles, extending 12
+to 15 miles in every direction from Charing Cross, and contained in 1881 a
+population of 4,764,312; but what is generally known as London covers 122
+square miles, containing, in 1881, 528,794 houses, and a population of
+3,814,574, averaging 7.21 persons per house, 49 per acre, and 31,267 per
+square mile. Now let us look at New York. South of Fortieth Street between
+the Hudson and East Rivers, New York has an area of 3,905 acres, a fraction
+over six square miles, exclusive of piers, and contained, according to the
+census of 1880, a population of 813,076. This gives 208 persons per acre.
+The census of 1880 reports the total number of dwellings in New York at
+73,684; total population, 1,206,299; average per dwelling, 16.37. Selecting
+for comparison an area about equal from the fifteen most densely populated
+districts or parishes of London, of an aggregate area of 3,896 acres, and
+with a total population of 746,305, we obtain 191.5 persons per acre. Thus
+briefly New York averaged 208 persons per acre, and 16.37 per dwelling;
+London, for the same area, 191.5 persons per acre, and 7.21 per house. But
+this comparison is scarcely fair, as in London only the most populous and
+poorest districts are included, corresponding to the entirely tenement
+districts of New York, while in the latter city it includes the richest and
+most fashionable sections, as well as the poorest. If tenement districts
+were taken alone, the population would be found much more dense, and New
+York proportionately much more densely populated. Taking four of the most
+thickly populated of the London districts (East London, Strand, Old Street,
+St. Luke's, St. Giles-in-the-Fields, and St. George, Bloomsbury), we find
+on a total area of 792 acres a population of 197,285, or an average of 249
+persons per acre. In four of the most densely populated wards of New York
+(10th, 11th, 13th, and 17th), we have on an area of 735 acres a population
+of 258,966, or 352 persons per acre. This is 40 per cent. higher than in
+London, the districts being about the same size, each containing about
+1-1/5 square miles. Apart from the greater crowding which takes place in
+New York, and the different style of buildings, another very fertile cause
+of the spreading of fires is the freer use of wood in their construction.
+It is asserted that in New York there is more than double the quantity of
+wood used in buildings per acre than in London. From a house census
+undertaken in 1882 by the New York Fire Department, moreover, it appears
+that there were 106,885 buildings including sheds, of which 28,798 houses
+were built of wood or other inflammable materials, besides 3,803 wooden
+sheds, giving a total of 32,601 wooden buildings.
+
+We are not aware that there are any wooden houses left in London. There are
+other minor causes which act as checks upon the spreading of fires in
+London. London houses are mostly small in size, and fires are thus confined
+to a limited space between brick walls. Their walls are generally low and
+well braced, which enable the firemen to approach them without danger.
+About 60 per cent. of London houses are less than 22 feet high from the
+pavement to the eaves; more than half of the remainder are less than 40
+feet high, very few being over 50 feet high. This, of course, excludes the
+newer buildings in the City. St. James's Palace does not exceed 40 feet,
+the Bank of England not over 30 feet in height; but these are exceptional
+structures. Fireproof roofings and projecting party walls also retard the
+spreading of conflagrations. The houses being comparatively low and small,
+the firemen are enabled to throw water easily over them, and to reach their
+roofs with short ladders. There is in London an almost universal absence of
+wooden additions and outbuildings, and the New York ash barrel or box kept
+in the house is also unknown. The local authorities in London keep a strict
+watch over the manufacture or storage of combustible materials in populous
+parts of the city. Although overhead telegraph wires are multiplying to an
+alarming extent in London, their number is nothing to be compared to their
+bewildering multitude in New York, where their presence is not only a
+hinderance to the operations of the firemen, but a positive danger to their
+lives. Finally--and this has already been partly dealt with in speaking of
+the comparative density of population of the two cities--a look at the map
+of London will show us how the River Thames and the numerous parks,
+squares, private grounds, wide streets, as well as the railways running
+into London, all act as effectual barriers to the extension of fires.
+
+The recent great conflagrations in the city vividly illustrate to Londoners
+what fire could do if their metropolis were built on the New York plan. The
+City, however, as we have remarked, is an exceptional part of London, and,
+taking the British metropolis as it is, with its hundreds of square miles
+of suburbs, and contrasting its condition with that of New York, we are led
+to adopt the opinion that London, with its excellent fire brigade, is safe
+from a destructive conflagration. It was stated above, and it is repeated
+here, that the fire brigade of New York is unsurpassed for promptness,
+skill, and heroic intrepidity, but their task, by contrast, is a heavy one
+in a city like New York, with its numerous wooden buildings, wooden or
+asphalt roofs, buildings from four to ten stories high, with long unbraced
+walls, weakened by many large windows, containing more than ten times the
+timber an average London house does, and that very inflammable, owing to
+the dry and hot American climate. But this is not all. In New York we find
+the five and six story tenement houses with two or three families on each
+floor, each with their private ash barrel or box kept handy in their rooms,
+all striving to keep warm during the severe winters of North America. We
+also find narrow streets and high buildings, with nothing to arrest the
+extension of a fire except a few small parks, not even projecting or
+effectual fire-walls between the several buildings. And to all this must be
+added the perfect freedom with which the city authorities of New York allow
+in its most populous portions large stables, timber yards, carpenters'
+shops, and the manufacture and storage of inflammable materials. Personal
+liberty could not be carried to a more dangerous extent. We ought to be
+thankful that in such matters individual freedom is somewhat hampered in
+our old-fashioned and quieter-going country.--_London Morning Post_.
+
+       *       *       *       *       *
+
+
+
+
+THE LATEST KNOWLEDGE ABOUT GAPES.
+
+
+The gape worm may be termed the _bete noir_ of the poultry-keeper--his
+greatest enemy--whether he be farmer or fancier. It is true there are some
+who declare that it is unknown in their poultry-yards--that they have never
+been troubled with it at all. These are apt to lay it down, as I saw a
+correspondent did in a recent number of the _Country Gentleman_, that the
+cause is want of cleanliness or neglect in some way. But I can vouch that
+that is not so. I have been in yards where everything was first-rate, where
+the cleanliness was almost painfully complete, where no fault in the way of
+neglect could be found, and yet the gapes were there; and on the other
+hand, I have known places where every condition seemed favorable to the
+development of such a disease, and there it was absent--this not in
+isolated cases, but in many. No, we must look elsewhere for the cause.
+
+Observations lead me to the belief that gapes are more than usually
+troublesome during a wet spring or summer following a mild winter. This
+would tend to show that the egg from which the worm (that is in itself the
+disease) emerges is communicated from the ground, from the food eaten, or
+the water drunk, in the first instance, but it is more than possible that
+the insects themselves may pass from one fowl to another. All this we can
+accept as a settled fact, and also any description of the way in which the
+parasitic worms attach themselves to the throats of the birds, and cause
+the peculiar gaping of the mouth which gives the name to the disease.
+
+Many remedies have been suggested, and my object now is to communicate some
+of the later ones--thus to give a variety of methods, so that in case of
+the failure of one, another will be at hand ready to be tried. It is a
+mistake always to pin the faith to one remedy, for the varying conditions
+found in fowls compel a different treatment. The old plan of dislodging the
+worms with a feather is well known, and need not be described again. But I
+may mention that in this country some have found the use of an ointment,
+first suggested by Mr. Lewis Wright, I believe, most valuable. This is made
+of mercurial ointment, two parts; pure lard, two parts; flour of sulphur,
+one part; crude petroleum, one part--and when mixed together is applied to
+the heads of the chicks as soon as they are dry after hatching. Many have
+testified that they have never found this to fail as a preventive, and if
+the success is to be attributed to the ointment, it would seem as if the
+insects are driven off by its presence, for the application to the heads
+merely would not kill the eggs.
+
+Some time ago Lord Walsingham offered, through the Entomological Society of
+London, a prize for the best life history of the gapes disease, and this
+has been won by the eminent French scientist M. Pierre Mégnin, whose essay
+has been published by the noble donor. His offer was in the interest of
+pheasant breeders, but the benefit is not confined to that variety of game
+alone, for it is equally applicable to all gallinaceous birds troubled with
+this disease. The pamphlet in question is a very valuable work, and gives
+very clearly the methods by which the parasite develops. But for our
+purpose it will be sufficient to narrate what M. Mégnin recommends for the
+cure of it. These are various, as will be seen, and comprise the experience
+of other inquirers as well as himself.
+
+He states that Montague obtained great success by a combination of the
+following methods: Removal from infested runs; a thorough change of food,
+hemp seed and green vegetables figuring largely in the diet; and for
+drinking, instead of plain water, an infusion of rue and garlic. And Mégnin
+himself mentions an instance of the value of garlic. In the years 1877 and
+1878, the pheasant preserves of Fontainebleau were ravaged by gapes. The
+disease was there arrested and totally cured, when a mixture, consisting of
+yolks of eggs, boiled bullock's heart, stale bread crumbs, and leaves of
+nettle, well mixed and pounded together with garlic, was given, in the
+proportion of one clove to ten young pheasants. The birds were found to be
+very fond of this mixture, but great care was taken to see that the
+drinking vessels were properly cleaned out and refilled with clean, pure
+water twice a day. This treatment has met with the same success in other
+places, and if any of your readers are troubled with gapes and will try it,
+I shall be pleased to see the results narrated in the columns of the
+_Country Gentleman_. Garlic in this case is undoubtedly the active
+ingredient, and as it is volatile, when taken into the stomach the breath
+is charged with it, and in this way (for garlic is a powerful vermifuge)
+the worms are destroyed.
+
+Another remedy recommended by M. Mégnin was the strong smelling vermifuge
+assafoetida, known sometimes by the suggestive name of "devil's dung." It
+has one of the most disgusting oders possible, and is not very pleasant to
+be near. The assafoetida was mixed with an equal part of powdered yellow
+gentian, and this was given to the extent of about 8 grains a day in the
+food. As an assistance to the treatment, with the object of killing any
+embryos in the drinking water, fifteen grains of salicylate of soda was
+mixed with a pint and three-quarters of water. So successful was this, that
+on M. De Rothschild's preserves at Rambouillet, where a few days before
+gapes were so virulent that 1,200 pheasants were found dead every morning,
+it succeeded in stopping the epidemic in a few days. But to complete the
+matter, M. Mégnin adds that it is always advisable to disinfect the soil of
+preserves. For this purpose, the best means of destroying any eggs or
+embryos it may contain is to water the ground with a solution of sulphuric
+acid, in the proportion of a pennyweight to three pints of water, and also
+birds that die of the disease should be deeply buried in lime.
+
+Fumigation with carbolic acid is an undoubted cure, but then it is a
+dangerous one, and unless very great care is taken in killing the worms,
+the bird is killed also. Thus many find this a risky method, and prefer
+some other. Lime is found to be a valuable remedy. In some districts of
+England, where lime-kilns abound, it is a common thing to take children
+troubled with whooping-cough there. Standing in the smoke arising from the
+kilns, they are compelled to breathe it. This dislodges the phlegm in the
+throat, and they are enabled to get rid of it. Except near lime-kilns, this
+cannot be done to chickens, but fine slaked lime can be used, either alone
+or mixed with powdered sulphur, two parts of the former to one of the
+latter. The air is charged with this fine powder, and the birds, breathing
+it, cough, and thus get rid of the worms, which are stupefied by the lime,
+and do not retain so firm a hold on the throat. An apparatus has recently
+been introduced to spread this lime powder. It is in the form of an
+air-fan, with a pointed nozzle, which is put just within the coop at night,
+when the birds are all within. The powder is already in a compartment made
+for it, and by the turning of a handle, it is driven through the nozzle,
+and the air within the coop charged with it. There is no waste of powder,
+nor any fear that it will not be properly distributed. Experienced pheasant
+and poultry breeders state that by the use of this once a week, gapes are
+effectually prevented. In this case, also, I shall be glad to learn the
+result if tried.
+
+STEPHEN BEALE.
+
+H----, Eng., Aug. 1.
+
+--_Country Gentleman_.
+
+       *       *       *       *       *
+
+
+
+
+WOLPERT'S METHOD OF ESTIMATING THE AMOUNT OF CARBONIC ACID IN THE AIR.
+
+
+There is a large number of processes and apparatus for estimating the
+amount of carbonic acid in the air. Some of them, such as those of
+Regnault, Reiset, the Montsouris observers (Fig. 1), and Brand, are
+accurate analytical instruments, and consequently quite delicate, and not
+easily manipulated by hygienists of middling experience. Others are less
+complicated, and also less exact, but still require quite a troublesome
+manipulation--such, for example, as the process of Pettenkofer, as modified
+by Fodor, that of Hesse, etc.
+
+[Illustration: APPARATUS FOR ESTIMATING THE CARBONIC ACID OF THE AIR.
+FIG. 1.--Montsouris Apparatus. FIG. 2.--Smith's Minimetric Apparatus. FIG.
+3.--Bertin-Sans Apparatus. FIG. 4.--Bubbling Glass. FIG. 5.--Pipette. FIG.
+6.--Arrangement of the U-shaped Tube. FIG. 7.--Wolpert's Apparatus.]
+
+Hygienists have for some years striven to obtain some very simple apparatus
+(rather as an indicator than an analytical instrument) that should permit
+it to be quickly ascertained whether the degree of impurity of a place was
+incompatible with health, and in what proportion it was so. It is from such
+efforts that have resulted the processes of Messrs. Smith. Lunge,
+Bertin-Sans, and the apparatus of Prof. Wolpert (Fig. 7).
+
+It is of the highest interest to ascertain the proportion of carbonic acid
+in the air, and especially in that of inhabited places, since up to the
+present this is the best means of finding out how much the air that we are
+breathing is polluted, and whether there is sufficient ventilation or not.
+Experiment has, in fact, demonstrated that carbonic acid increases in the
+air of inhabited rooms in the same way as do those organic matters which
+are difficult of direct estimation. Although a few ten-thousandths more of
+carbonic acid in our air cannot of themselves endanger us, yet they have on
+another hand a baneful significance, and, indeed, the majority of
+hygienists will not tolerate more than six ten-millionths of this element
+in the air of dwellings, and some of them not more than five
+ten-millionths.
+
+Carbonic acid readily betrays its presence through solutions of the
+alkaline earths such as baryta and chalk, in which its passage produces an
+insoluble carbonate, and consequently makes the liquid turbid. If, then,
+one has prepared a solution of baryta or lime, of which a certain volume is
+made turbid by the passage of a likewise known volume of CO_{2}, it will be
+easy to ascertain how much CO_{2} a certain air contains, from the volume
+of the latter that it will be necessary to pass through the basic solution
+in order to obtain the amount of turbidity that has been taken as a
+standard. The problem consists in determining the minimum of air required
+to make the known solution turbid. Hence the name "minimetric estimation,"
+that has been given to this process. Prof. Lescoeur has had the goodness to
+construct for me a Smith's minimetric apparatus (Fig. 2) with the ingenious
+improvements that have been made in it by Mr. Fischli, assistant to Prof.
+Weil, of Zurich. I have employed it frequently, and I use it every year in
+my lectures. I find it very practical, provided one has got accustomed to
+using it. It is, at all events, of much simpler manipulation than that of
+Bertin-Sans, although the accuracy of the latter may be greater (Figs. 3,
+4, 5, and 6). But it certainly has more than one defect, and some of the
+faults that have been found with it are quite serious. The worst of these
+consists in the difficulty of catching the exact moment at which the
+turbidity of the basic liquid is at the proper point for arresting the
+operation. In addition to this capital defect, it is regrettable that it is
+necessary to shake the flask that contains the solution after every
+insufflation of air, and also that the play of the valves soon becomes
+imperfect. Finally, Mr. Wolpert rightly sees one serious drawback to the
+use of baryta in an apparatus that has to be employed in schools, among
+children, and that is that this substance is poisonous. This gentleman
+therefore replaces the solution of baryta by water saturated with lime,
+which costs almost nothing, and the preparation of which is exceedingly
+simple. Moreover, it is a harmless agent.
+
+The apparatus consists of two parts. The first of these is a glass tube
+closed at one end, and 12 cm. in length by 12 mm. in diameter. Its bottom
+is of porcelain, and bears on its inner surface the date 1882 in black
+characters. Above, and at the level that corresponds to a volume of three
+cubic centimeters, there is a black line which serves as an invariable
+datum point. A rubber bulb of twenty-eight cubic centimeters capacity is
+fixed to a tube which reaches its bottom, and is flanged at the other
+extremity (Fig. 7).
+
+The operation is as follows:
+
+The saturated, but limpid, solution of lime is poured into the first tube
+up to the black mark, the tube of the air bulb is introduced into the lime
+water in such a way that its orifice shall be in perfect contact with the
+bottom of the other tube, and then, while the bulb is held between the fore
+and middle fingers of the upturned hand, one presses slowly with the thumb
+upon its bottom so as to expel all the air that it contains. This air
+enters the lime-water bubble by bubble. After this the tube is removed from
+the water, and the bulb is allowed to fill with air, and the same maneuver
+is again gone through with. This is repeated until the figures 1882, looked
+at from above, cease to be clearly visible, and disappear entirely after
+the contents of the tube have been vigorously shaken.
+
+The measures are such that the turbidity supervenes at once if the air in
+the bulb contains twenty thousandths of CO_{2}. If it becomes necessary to
+inject the contents of the bulb into the water twice, it is clear that the
+proportion is only ten thousandths; and if it requires ten injections the
+air contains ten times less CO_{2} than that having twenty thousandths, or
+only two per cent. A table that accompanies the apparatus has been
+constructed upon this basis, and does away with the necessity of making
+calculations.
+
+An air that contained ten thousandths of CO_{2}, or even five, would be
+almost as deleterious, in my opinion, as one of two per cent. It is of no
+account, then, to know the proportions intermediate to these round numbers.
+Yet it is possible, if the case requires it, to obtain an indication
+between two consecutive figures of the scale by means of another bulb whose
+capacity is only half that of the preceding. Thus, two injections of the
+large bulb, followed by one of the small, or two and a half injections,
+correspond to a richness of 8 thousandths of CO_{2}; and 5½ to 3.6
+thousandths. This half-bulb serves likewise for another purpose. From the
+moment that the large bulb makes the lime-water turbid with an air
+containing two per cent. of CO_{2}, it is clear that the small one can
+cause the same turbidity only with air twice richer in CO_{2}, _i.e._, of
+four per cent.
+
+This apparatus, although it makes no pretensions to extreme accuracy, is
+capable of giving valuable information. The table that accompanies it is
+arranged for a temperature of 17° and a pressure of 740 mm. But different
+meteorological conditions do not materially alter the results. Thus, with
+10° less it would require thirty-one injections instead of thirty, and
+CO_{2} would be 0.64 per 1,000 instead of 0.66; and with 10° more, thirty
+injections instead of thirty one.
+
+The apparatus is contained in a box that likewise holds a bottle of
+lime-water sufficient for a dozen analyses, the table of proportions of
+CO_{2}, and the apparatus for cleaning the tubes. The entire affair is
+small enough to be carried in the pocket.--_J. Arnould, in Science et
+Nature_.
+
+       *       *       *       *       *
+
+[NATURE.]
+
+
+
+
+THE VOYAGE OF THE VETTOR PISANI.
+
+
+Knowing how much _Nature_ is read by all the naturalists of the world, I
+send these few lines, which I hope will be of some interest.
+
+The Italian R.N. corvette Vettor Pisani left Italy in April, 1882, for a
+voyage round the world with the ordinary commission of a man-of-war. The
+Minister of Marine, wishing to obtain scientific results, gave orders to
+form, when possible, a marine zoological collection, and to carry on
+surveying, deep-sea soundings, and abyssal thermometrical measurements. The
+officers of the ship received their different scientific charges, and Prof.
+Dohrn, director of the Zoological Station at Naples, gave to the writer
+necessary instructions for collecting and preserving sea animals.
+
+At the end of 1882 the Vettor Pisani visited the Straits of Magellan, the
+Patagonian Channels, and Chonos and Chiloe islands; we surveyed the Darwin
+Channel, and following Dr. Cuningham's work (who visited these places on
+board H.M.S. Nassau), we made a numerous collection of sea animals by
+dredging and fishing along the coasts.
+
+While fishing for a big shark in the Gulf of Panama during the stay of our
+ship in Taboga Island, one day in February, with a dead clam, we saw
+several great sharks some miles from our anchorage. In a short time several
+boats with natives went to sea, accompanied by two of the Vettor Pisani's
+boats.
+
+Having wounded one of these animals in the lateral part of the belly, we
+held him with lines fixed to the spears; he then began to describe a very
+narrow curve, and irritated by the cries of the people that were in the
+boats, ran off with a moderate velocity. To the first boat, which held the
+lines just mentioned, the other boats were fastened, and it was a rather
+strange emotion to feel ourselves towed by the monster for more than three
+hours with a velocity that proved to be two miles per hour. One of the
+boats was filled with water. At last the animal was tired by the great loss
+of blood, and the boats assembled to haul in the lines and tow the shark on
+shore.
+
+With much difficulty the nine boats towed the animal alongside the Vettor
+Pisani to have him hoisted on board, but it was impossible on account of
+his colossal dimensions. But as it was high water we went toward a sand
+beach with the animal, and we had him safely stranded at night.
+
+With much care were inspected the mouth, the nostrils, the ears, and all
+the body, but no parasite was found. The eyes were taken out and prepared
+for histological study. The set of teeth was all covered by a membrane that
+surrounded internally the lips; the teeth are very little, and almost in a
+rudimental state. The mouth, instead of opening in the inferior part of the
+head, as in common sharks, was at the extremity of the head; the jaws
+having the same bend.
+
+Cutting the animal on one side of the backbone we met (1) a compact layer
+of white fat 20 centimeters deep; (2) the cartilaginous ribs covered with
+blood vessels; (3) a stratum of flabby, stringy, white muscle, 60
+centimeters high, apparently in adipose degeneracy; (4) the stomach.
+
+By each side of the backbone he had three chamferings, or flutings, that
+were distinguished by inflected interstices. The color of the back was
+brown with yellow spots that became close and small toward the head, so as
+to be like marble spots. The length of the shark was 8.90 m. from the mouth
+to the _pinna caudalis_ extremity, the greatest circumference 6.50 m., and
+2.50 m. the main diameter (the outline of the two projections is made for
+giving other dimensions).
+
+The natives call the species _Tintoreva_, and the most aged of the village
+had only once before fished such an animal, but smaller. While the animal
+was on board we saw several _Remora_ about a foot long drop from his mouth;
+it was proved that these fish lived fixed to the palate, and one of them
+was pulled off and kept in the zoological collection of the ship.
+
+The Vettor Pisani has up the present visited Gibraltar, Cape Verde Islands,
+Pernambuco, Rio Janeiro, Monte Video, Valparaiso, many ports of Peru,
+Guayaquil, Panama, Galapagos Islands, and all the collections were up to
+this sent to the Zoological Station at Naples to be studied by the
+naturalists. By this time the ship left Callao for Honolulu, Manila, Hong
+Kong, and, as the Challenger had not crossed the Pacific Ocean in these
+directions, we made several soundings and deep-sea thermometrical
+measurements from Callao to Honolulu. Soundings are made with a steel wire
+(Thompson system) and a sounding-rod invented by J. Palumbo, captain of the
+ship. The thermometer employed is a Negretti and Zambra deep-sea
+thermometer, improved by Captain Maguaghi (director of the Italian R.N.
+Hydrographic Office).
+
+With the thermometer wire has always been sent down a tow-net which opens
+and closes automatically, also invented by Captain Palumbo. This tow-net
+has brought up some little animals that I think are unknown.
+
+G. CHIERCHIA.
+
+
+Honolulu July 1.
+
+The shark captured by the Vettor Pisani in the Gulf of Panama is _Rhinodon
+typicus_, probably the most gigantic fish in existence. Mr. Swinburne Ward,
+formerly commissioner of the Seychelles, has informed me that it attains to
+a length of 50 feet or more, which statement was afterward confirmed by
+Prof. E.P. Wright. Originally described by Sir A. Smith from a single
+specimen which was killed in the neighborhood of Cape Town, this species
+proved to be of not uncommon occurrence in the Seychelles Archipelago,
+where it is known by the name of "Chagrin." Quite recently Mr. Haly
+reported the capture of a specimen on the coast of Ceylon. Like other large
+sharks (_Carcharodon rondeletii, Selache maxima_, etc.), Rhinodon has a
+wide geographical range, and the fact of its occurrence on the Pacific
+coast of America, previously indicated by two sources, appears now to be
+fully established. T. Gill in 1865 described a large shark known in the
+Gulf of California by the name of "Tiburon ballenas" or whale-shark, as a
+distinct genus--_Micristodus punctatus_--which, in my opinion, is the same
+fish. And finally, Prof. W. Nation examined in 1878 a specimen captured at
+Callao. Of this specimen we possess in the British Museum a portion of the
+dental plate. The teeth differ in no respect from those of a Seychelles
+Chagrin; they are conical, sharply pointed, recurved, with the base of
+attachment swollen. Making no more than due allowance for such variations
+in the descriptions by different observers as are unavoidable in accounts
+of huge creatures examined by some in a fresh, by others in a preserved,
+state, we find the principal characteristics identical in all these
+accounts, viz.: the form of the body, head, and snout, relative
+measurements, position of mouth, nostrils, and eyes, dentition, peculiar
+ridges on the side of the trunk and tail, coloration, etc. I have only to
+add that this shark is stated to be of mild disposition and quite harmless.
+Indeed, the minute size of its teeth has led to the belief in the
+Seychelles that it is a herbivorous fish, which, however, is not probable.
+
+ALBERT GUNTHER.
+
+Natural History Museum, _July 30_.
+
+       *       *       *       *       *
+
+
+
+
+THE GREELY ARCTIC EXPEDITION.
+
+
+[Illustration: THE GREELY ARCTIC EXPEDITION.--THE FARTHEST POINT NORTH.]
+
+Some account has been given of the American Meteorological Expedition,
+commanded by Lieutenant, now Major, Greely, of the United States Army, in
+the farthest north channels, beyond Smith Sound, that part of the Arctic
+regions where the British Polar expedition, in May, 1876, penetrated to
+within four hundred geographical miles of the North Pole. The American
+expedition, in 1883, succeeded in getting four miles beyond, this being
+effected by a sledge party traveling over the snow from Fort Conger, the
+name they had given to their huts erected on the western shore near
+Discovery Cove, in Lady Franklin Sound. The farthest point reached, on May
+18, was in latitude 83 deg. 24 min. N.; longitude 40 deg. 46 min. W., on
+the Greenland coast. The sledge party was commanded by Lieutenant Lockwood,
+and the following particulars are supplied by Sergeant Brainerd, who
+accompanied Lieutenant Lockwood on the expedition. During their sojourn in
+the Arctic regions the men were allowed to grow the full beard, except
+under the mouth, where it was clipped short. They wore knitted mittens, and
+over these heavy seal-skin mittens were drawn, connected by a tanned
+seal-skin string that passed over the neck, to hold them when the hands
+were slipped out. Large tanned leather pockets were fastened outside the
+jackets, and in very severe weather jerseys were sometimes worn over the
+jackets for greater protection against the intense cold. On the sledge
+journeys the dogs were harnessed in a fan-shaped group to the traces, and
+were never run tandem. In traveling, the men were accustomed to hold on to
+the back of the sledge, never going in front of the team, and often took
+off their heavy overcoats and threw them on the load. When taking
+observations with the sextant, Lieutenant Lockwood generally reclined on
+the snow, while Sergeant Brainerd called time and made notes, as shown in
+our illustration. When further progress northward was barred by open water,
+and the party almost miraculously escaped drifting into the Polar sea,
+Lieutenant Lockwood erected, at the highest point of latitude reached by
+civilized man, a pyramidal-shaped cache of stones, six feet square at the
+base, and eight or nine feet high. In a little chamber about a foot square
+half-way to the apex, and extending to the center of the pile, he placed a
+self-recording spirit thermometer, a small tin cylinder containing records
+of the expedition, and then sealed up the aperture with a closely fitting
+stone. The cache was surmounted with a small American flag made by Mrs.
+Greely, but there were only thirteen stars, the number of the old
+revolutionary flag. From the summit of Lockwood Island, the scene presented
+in our illustration, 2,000 feet above the sea, Lieutenant Lockwood was
+unable to make out any land to the north or the northwest. "The awful
+panorama of the Arctic which their elevation spread out before them made a
+profound impression upon the explorers. The exultation which was natural to
+the achievement which they found they had accomplished was tempered by the
+reflections inspired by the sublime desolation of that stern and silent
+coast and the menace of its unbroken solitude. Beyond to the eastward was
+the interminable defiance of the unexplored coast--black, cold, and
+repellent. Below them lay the Arctic Ocean, buried beneath frozen chaos. No
+words can describe the confusion of this sea of ice--the hopeless asperity
+of it, the weariness of its torn and tortured surface. Only at the remote
+horizon did distance and the fallen snow mitigate its roughness and soften
+its outlines; and beyond it, in the yet unattainable recesses of the great
+circle, they looked toward the Pole itself. It was a wonderful sight, never
+to be forgotten, and in some degree a realization of the picture that
+astronomers conjure to themselves when the moon is nearly full, and they
+look down into the great plain which is called the Ocean of Storms, and
+watch the shadows of sterile and airless peaks follow a slow procession
+across its silver surface."--_Illustrated London News_.
+
+       *       *       *       *       *
+
+
+
+
+THE NILE EXPEDITION.
+
+
+[Illustration: WHALER GIG FOR THE NILE.]
+
+As soon as the authorities had finally made up their minds to send a
+flotilla of boats to Cairo for the relief of Khartoum, not a moment was
+lost in issuing orders to the different shipbuilding contractors for the
+completion, with the utmost dispatch, of the 400 "whaler-gigs" for service
+on the Nile. They are light-looking boats, built of white pine, and weigh
+each about 920 lb., that is without the gear, and are supposed to carry
+four tons of provisions, ammunition, and camp appliances, the food being
+sufficient for 100 days. The crew will number twelve men, soldiers and
+sailors, the former rowing, while the latter (two) will attend the helm.
+Each boat will be fitted with two lug sails, which can be worked reefed, so
+as to permit an awning to be fitted underneath for protection to the men
+from the sun. As is well known, the wind blows for two or three months
+alternately up and down the Nile, and the authorities expect the flotilla
+will have the advantage of a fair wind astern for four or five days at the
+least. On approaching the Cataracts, the boats will be transported on
+wooden rollers over the sand to the next level for relaunching.
+
+       *       *       *       *       *
+
+
+
+
+THE PROPER TIME FOR CUTTING TIMBER.
+
+
+_To the Editor of the Oregonian:_
+
+Believing that any ideas relating to this matter will be of some interest
+to your readers in this heavily-timbered region, I therefore propose giving
+you my opinion and conclusions arrived at after having experimented upon
+the cutting and use of timber for various purposes for a number of years
+here upon the Pacific coast.
+
+This, we are all well aware, is a very important question, and one very
+difficult to answer, since it requires observation and experiment through a
+course of many years to arrive at any definite conclusion; and it is a
+question too upon which even at the present day there exists a great
+difference of opinion among men who, being engaged in the lumber business,
+are thereby the better qualified to form an opinion.
+
+Many articles have been published in the various papers of the country upon
+this question for the past thirty years, but in all cases an opinion only
+has been given, which, at the present day, such is the advance and higher
+development of the intellectual faculties of man, that a mere opinion upon
+any question without sufficient and substantial reasons to back it is of
+little value.
+
+My object in writing this is not simply to give an opinion, but how and the
+methods used by which I adopted such conclusions, as well also as the
+reasons why timber is more durable and better when cut at a certain season
+of the year than when cut at any other.
+
+In the course of my investigations of this question for the past thirty
+years, I have asked the opinion of a great many persons who have been
+engaged in the lumber business in various States of the Union, from Maine
+to Wisconsin, and they all agree upon one point, viz., that the winter time
+is the proper time for cutting timber, although none has ever been able to
+give a reason why, only the fact that such was the case, and therefore
+drawing the inference that it was the proper time when timber should be
+cut; and so it is, for one reason only, however, and that is the
+convenience for handling or moving timber upon the snow and ice.
+
+It was while engaged in the business of mining in the mountains of
+California in early days, and having occasion to work often among timber,
+in removing stumps, etc., it was while so engaged that I noticed one
+peculiar fact, which was this--that the stumps of some trees which had been
+cut but two or three years had decayed, while others of the same size and
+variety of pine which had been cut the same year were as sound and firm as
+when first cut. This seemed strange to me, and I found upon inquiry of old
+lumbermen who had worked among timber all their lives, that it was strange
+to them also, and they could offer no explanation; and it was the
+investigation of this singular fact that led me to experiment further upon
+the problem of cutting timber.
+
+It was not, however, until many years after, and when engaged in clearing
+land for farming purposes, that I made the discovery why some stumps should
+decay sooner than others of the same size and variety, even when cut a few
+months afterward.
+
+I had occasion to clear several acres of land which was covered with a very
+dense growth of young pines from two to six inches in diameter (this work
+for certain reasons is usually done in the winter). The young trees, not
+being suitable for fuel, are thrown into piles and burned upon the ground.
+Such land, therefore, on account of the stumps is very difficult to plow,
+as the stumps do not decay for three or four years, while most of the
+larger ones remain sound even longer.
+
+But, for the purpose of experimenting, I cleaned a few acres of ground in
+the spring, cutting them in May and June. I trimmed the poles, leaving them
+upon the ground, and when seasoned hauled them to the house for fuel, and
+found that for cooking or heating purposes they were almost equal to oak;
+and it was my practice for many years afterward to cut these young pines in
+May or June for winter fuel.
+
+I found also that the stumps, instead of remaining sound for any length of
+time, decayed so quickly that they could all be plowed up the following
+spring.
+
+From which facts I draw these conclusions: that if in the cutting of timber
+the main object is to preserve the stumps, cut your trees in the fall or
+winter; but if the value of the timber is any consideration, cut your trees
+in the spring after the sap has ascended the tree, but before any growth
+has taken place or new wood has been formed.
+
+I experimented for many years also in the cutting of timber for fencing,
+fence posts, etc., and with the same results. Those which were cut in the
+spring and set after being seasoned were the most durable, such timber
+being much lighter, tougher, and in all respects better for all variety of
+purposes.
+
+Having given some little idea of the manner in which I experimented, and
+the conclusions arrived at as to the proper time when timber should be cut,
+I now propose to give what are, in my opinion, the reasons why timber cut
+in early summer is much better, being lighter, tougher and more durable
+than if cut at any other time. Therefore, in order to do this it is
+necessary first to explain the nature and value of the sap and the growth
+of a tree.
+
+We find it to be the general opinion at present, as it perhaps has always
+been among lumbermen and those who work among timber, that the sap of a
+tree is an evil which must be avoided if possible, for it is this which
+causes decay and destroys the life and good qualities of all wood when
+allowed to remain in it for an unusual length of time, but that this is a
+mistaken idea I will endeavor to show, not that the decay is due to the
+sap, but to the time when the tree was felled.
+
+We find by experiment in evaporating a quantity of sap of the pine, that it
+is water holding in solution a substance of a gummy nature, being composed
+of albumen and other elementary matters, which is deposited within the
+pores of the wood from the new growth of the tree; that these substances in
+solution, which constitute the sap, and which promote the growth of the
+tree, should have a tendency to cause decay of the wood is an
+impossibility. The injury results from the water only, and the improper
+time of felling the tree.
+
+Of the process in which the sap promotes the growth of the tree, the
+scientist informs us that it is extracted from the soil, and flows up
+through the pores of the wood of the tree, where it is deposited upon the
+fiber, and by a peculiar process of nature the albumen forms new cells,
+which in process of formation crowd and push out from the center, thus
+constituting the growth of the tree in all directions from center to
+circumference. Consequently this new growth of wood, being composed
+principally of albumen, is of a soft, spongy nature, and under the proper
+conditions will decay very rapidly, which can be easily demonstrated by
+experiment.
+
+Hence, we must infer that the proper time for felling the tree is when the
+conditions are such that the rapid decay of a new growth of wood is
+impossible; and this I have found by experiment to be in early summer,
+after the sap has ascended the tree, but before any new growth of wood has
+been formed. The new growth of the previous season is now well matured, has
+become hard and firm, and will not decay. On the contrary, the tree being
+cut when such new growth has not well matured, decay soon takes place, and
+the value of the timber is destroyed. The effect of this cutting and use of
+timber under the wrong conditions can be seen all around us. In the timbers
+of the bridges, in the trestlework and ties of railroads and in the piling
+of the wharves will be found portions showing rapid decay, while other
+portions are yet firm and in sound condition.
+
+Much more might be said in the explanation of this subject, but not wishing
+to extend the subject to an improper length, I will close. I would,
+however, say in conclusion that persons who have the opportunities and the
+inclination can verify the truth of a portion, at least, of what I have
+stated, in a simple manner and in a short time; for instance, by cutting
+two or three young fir or spruce saplings, say about six inches in
+diameter, mark them when cut, and also mark the stumps by driving pegs
+marked to correspond with the trees. Continue this monthly for the space of
+about one year, and note the difference in the wood, which should be left
+out and exposed to the weather until seasoned.
+
+C.W. HASKINS.
+
+       *       *       *       *       *
+
+
+
+
+RAISING FERNS FROM SPORES.
+
+
+[Illustration: 1, PAN; 2, BELL GLASS; 3, SMALL POTS AND LABELS.]
+
+This plan, of which I give a sketch, has been in use by myself for many
+years, and most successfully. I have at various times given it to growers,
+but still I hear of difficulties. Procure a good sized bell-glass and an
+earthenware pan without any holes for drainage. Prepare a number of small
+pots, all filled for sowing, place them inside the pan, and fit the glass
+over them, so that it takes all in easily. Take these filled small pots out
+of the pan, place them on the ground, and well water them with boiling
+water to destroy all animal and vegetable life, and allow them to get
+perfectly cold; use a fine rose. Then taking each small pot separately, sow
+the spores on the surface and label them; do this with the whole number,
+and then place them in the pan under the bell-glass. This had better be
+done in a room, so that nothing foreign can grow inside. Having arranged
+the pots and placed the glass over them, and which should fit down upon the
+pan with ease, take a clean sponge, and tearing it up pack the pieces round
+the outside of the glass, and touching the inner side of the pan all round.
+Water this with cold water, so that the sponge is saturated. Do this
+whenever required, and always use water that has been boiled. At the end of
+six weeks or so the prothallus will perhaps appear, certainly in a week or
+two more; perhaps from unforeseen circumstances not for three months.
+Slowly these will begin to show themselves as young ferns, and most
+interesting it is to watch the results. As the ferns are gradually
+increasing in size pass a small piece of slate under the edge of the
+bell-glass to admit air, and do this by very careful degrees, allowing more
+and more air to reach them. Never water overhead until the seedlings are
+acclimated and have perfect form as ferns, and even then water at the edges
+of the pots. In due time carefully prick out, and the task so interesting
+to watch is performed.--_The Garden_.
+
+       *       *       *       *       *
+
+
+
+
+THE LIFE HISTORY OF VAUCHERIA.
+
+[Footnote: Read before the San Francisco Microscopical Society, August 13,
+and furnished for publication in the _Press_.]
+
+By A.H. BRECKENFELD.
+
+
+Nearly a century ago, Vaucher, the celebrated Genevan botanist, described a
+fresh water filamentous alga which he named _Ectosperma geminata_, with a
+correctness that appears truly remarkable when the imperfect means of
+observation at his command are taken into consideration. His pupil, De
+Candolle, who afterward became so eminent a worker in the same field, when
+preparing his "Flora of France," in 1805, proposed the name of _Vaucheria_
+for the genus, in commemoration of the meritorious work of its first
+investigator. On March 12, 1826, Unger made the first recorded observation
+of the formation and liberation of the terminal or non-sexual spores of
+this plant. Hassall, the able English botanist, made it the subject of
+extended study while preparing his fine work entitled "A History of the
+British Fresh Water Algæ," published in 1845. He has given us a very
+graphic description of the phenomenon first observed by Unger. In 1856
+Pringsheim described the true sexual propagation by oospores, with such
+minuteness and accuracy that our knowledge of the plant can scarcely be
+said to have essentially increased since that time.
+
+[Illustration: GROWTH OF THE ALGA, VAUCHERIA, UNDER THE MICROSCOPE.]
+
+_Vaucheria_ has two or three rather doubtful marine species assigned to it
+by Harvey, but the fresh water forms are by far the more numerous, and it
+is to some of these I would call your attention for a few moments this
+evening. The plant grows in densely interwoven tufts, these being of a
+vivid green color, while the plant is in the actively vegetative condition,
+changing to a duller tint as it advances to maturity. Its habitat (with the
+exceptions above noted) is in freshwater--usually in ditches or slowly
+running streams. I have found it at pretty much all seasons of the year, in
+the stretch of boggy ground in the Presidio, bordering the road to Fort
+Point. The filaments attain a length of several inches when fully
+developed, and are of an average diameter of 1/250 (0.004) inch. They
+branch but sparingly, or not at all, and are characterized by consisting of
+a single long tube or cell, not divided by septa, as in the case of the
+great majority of the filamentous algæ. These tubular filaments are
+composed of a nearly transparent cellulose wall, including an inner layer
+thickly studded with bright green granules of chlorophyl. This inner layer
+is ordinarily not noticeable, but it retracts from the outer envelope when
+subjected to the action of certain reagents, or when immersed in a fluid
+differing in density from water, and it then becomes distinctly visible, as
+may be seen in the engraving (Fig. 1). The plant grows rapidly and is
+endowed with much vitality, for it resists changes of temperature to a
+remarkable degree. _Vaucheria_ affords a choice hunting ground to the
+microscopist, for its tangled masses are the home of numberless infusoria,
+rotifers, and the minuter crustacea, while the filaments more advanced in
+age are usually thickly incrusted with diatoms. Here, too, is a favorite
+haunt of the beautiful zoophytes, _Hydra vividis_ and _H. vulgaris_, whose
+delicate tentacles may be seen gracefully waving in nearly every gathering.
+
+
+REPRODUCTION IN VAUCHERIA.
+
+After the plant has attained a certain stage in its growth, if it be
+attentively watched, a marked change will be observed near the ends of the
+filaments. The chlorophyl appears to assume a darker hue, and the granules
+become more densely crowded. This appearance increases until the extremity
+of the tube appears almost swollen. Soon the densely congregated granules
+at the extreme end will be seen to separate from the endochrome of the
+filament, a clear space sometimes, but not always, marking the point of
+division. Here a septum or membrane appears, thus forming a cell whose
+length is about three or four times its width, and whose walls completely
+inclose the dark green mass of crowded granules (Fig. 1, b). These contents
+are now gradually forming themselves into the spore or "gonidium," as
+Carpenter calls it, in distinction from the true sexual spores, which he
+terms "oospores." At the extreme end of the filament (which is obtusely
+conical in shape) the chlorophyl grains retract from the old cellulose
+wall, leaving a very evident clear space. In a less noticeable degree, this
+is also the case in the other parts of the circumference of the cell, and,
+apparently, the granular contents have secreted a separate envelope
+entirely distinct from the parent filament. The grand climax is now rapidly
+approaching. The contents of the cell near its base are now so densely
+clustered as to appear nearly black (Fig. 1, c), while the upper half is of
+a much lighter hue and the separate granules are there easily
+distinguished, and, if very closely watched, show an almost imperceptible
+motion. The old cellulose wall shows signs of great tension, its conical
+extremity rounding out under the slowly increasing pressure from within.
+Suddenly it gives way at the apex. At the same instant, the inclosed
+gonidium (for it is now seen to be fully formed) acquires a rotary motion,
+at first slow, but gradually increasing until it has gained considerable
+velocity. Its upper portion is slowly twisted through the opening in the
+apex of the parent wall, the granular contents of the lower end flowing
+into the extruded portion in a manner reminding one of the flow of
+protoplasm in a living amoeba. The old cell wall seems to offer
+considerable resistance to the escape of the gonidium, for the latter,
+which displays remarkable elasticity, is pinched nearly in two while
+forcing its way through, assuming an hour glass shape when about half out.
+The rapid rotation of the spore continues during the process of emerging,
+and after about a minute it has fully freed itself (Fig 1, a). It
+immediately assumes the form of an ellipse or oval, and darts off with
+great speed, revolving on its major axis as it does so. Its contents are
+nearly all massed in the posterior half, the comparatively clear portion
+invariably pointing in advance. When it meets an obstacle, it partially
+flattens itself against it, then turns aside and spins off in a new
+direction. This erratic motion is continued for usually seven or eight
+minutes. The longest duration I have yet observed was a little over nine
+and one-half minutes. Hassall records a case where it continued for
+nineteen minutes. The time, however, varies greatly, as in some cases the
+motion ceases almost as soon as the spore is liberated, while in open
+water, unretarded by the cover glass or other obstacles, its movements have
+been seen to continue for over two hours.
+
+The motile force is imparted to the gonidium by dense rows of waving cilia
+with which it is completely surrounded. Owing to their rapid vibration, it
+is almost impossible to distinguish them while the spore is in active
+motion, but their effect is very plainly seen on adding colored pigment
+particles to the water. By subjecting the cilia to the action of iodine,
+their motion is arrested, they are stained brown, and become very plainly
+visible.
+
+After the gonidium comes gradually to a rest its cilia soon disappear, it
+becomes perfectly globular in shape, the inclosed granules distribute
+themselves evenly throughout its interior, and after a few hours it
+germinates by throwing out one, two, or sometimes three tubular
+prolongations, which become precisely like the parent filament (Fig 2).
+
+Eminent English authorities have advanced the theory that the ciliated
+gonidium of _Vaucheria_ is in reality a densely crowded aggregation of
+biciliated zoospores, similar to those found in many other confervoid algæ.
+Although this has by no means been proved, yet I cannot help calling the
+attention of the members of this society to a fact which I think strongly
+bears out the said theory: While watching a gathering of _Vaucheria_ one
+morning when the plant was in the gonidia-forming condition (which is
+usually assumed a few hours after daybreak), I observed one filament, near
+the end of which a septum had formed precisely as in the case of ordinary
+filaments about to develop a spore. But, instead of the terminal cell being
+filled with the usual densely crowded cluster of dark green granules
+constituting the rapidly forming spore, it contained hundreds of actively
+moving, nearly transparent zoospores, _and nothing else_. Not a single
+chlorophyl granule was to be seen. It is also to be noted as a significant
+fact, that the cellulose wall was _intact_ at the apex, instead of showing
+the opening through which in ordinary cases the gonidium escapes. It would
+seem to be a reasonable inference, I think, based upon the theory above
+stated, that in this case the newly formed gonidium, unable to escape from
+its prison by reason of the abnormal strength of the cell wall, became
+after a while resolved into its component zoospores.
+
+
+WONDERS OF REPRODUCTION.
+
+I very much regret that my descriptive powers are not equal to conveying a
+sufficient idea of the intensely absorbing interest possessed by this
+wonderful process of spore formation. I shall never forget the bright sunny
+morning when for the first time I witnessed the entire process under the
+microscope, and for over four hours scarcely moved my eyes from the tube.
+To a thoughtful observer I doubt if there is anything in the whole range of
+microscopy to exceed this phenomenon in point of startling interest. No
+wonder that its first observer published his researches under the caption
+of "The Plant at the Moment of becoming an Animal."
+
+
+FORMATION OF OTHER SPORES.
+
+The process of spore formation just described, it will be seen, is entirely
+non-sexual, being simply a vegetative process, analogous to the budding of
+higher plants, and the fission of some of the lower plants and animals.
+_Vaucheria_ has, however, a second and far higher mode of reproduction,
+viz., by means of fertilized cells, the true oospores, which, lying dormant
+as resting spores during the winter, are endowed with new life by the
+rejuvenating influences of spring. Their formation may be briefly described
+as follows:
+
+When _Vaucheria_ has reached the proper stage in its life cycle, slight
+swellings appear here and there on the sides of the filament. Each of these
+slowly develops into a shape resembling a strongly curved horn. This
+becomes the organ termed the _antheridium_, from its analogy in function to
+the anther of flowering plants. While this is in process of growth,
+peculiar oval capsules or sporangia (usually 2 to 5 in number) are formed
+in close proximity to the antheridium. In some species both these organs
+are sessile on the main filament, in others they appear on a short pedicel
+(Figs. 3 and 4). The upper part of the antheridium becomes separated from
+the parent stem by a septum, and its contents are converted into ciliated
+motile antherozoids. The adjacent sporangia also become cut off by septa,
+and the investing membrane, when mature, opens: it a beak-like
+prolongation, thus permitting the inclosed densely congregated green
+granules to be penetrated by the antherozoids which swarm from the
+antheridium at the same time. After being thus fertilized the contents of
+the sporangium acquire a peculiar oily appearance, of a beautiful emerald
+color, an exceedingly tough but transparent envelope is secreted, and thus
+is constituted the fully developed oospore, the beginner of a new
+generation of the plant. After the production of this oospore the parent
+filament gradually loses its vitality and slowly decays.
+
+The spore being thus liberated, sinks to the bottom. Its brilliant hue has
+faded and changed to a reddish brown, but after a rest of about three
+months (according to Pringsheim, who seems to be the only one who has ever
+followed the process of oospore formation entirely through), the spore
+suddenly assumes its original vivid hue and germinates into a young
+_Vaucheria_.
+
+
+CHARM OF MICROSCOPICAL STUDY.
+
+This concludes the account of my very imperfect attempt to trace the life
+history of a lowly plant. Its study has been to me a source of ever
+increasing pleasure, and has again demonstrated how our favorite instrument
+reveals phenomena of most absorbing interest in directions where the
+unaided eye finds but little promise. In walking along the banks of the
+little stream, where, half concealed by more pretentious plants, our humble
+_Vaucheria_ grows, the average passer by, if he notices it at all, sees but
+a tangled tuft of dark green "scum." Yet, when this is examined under the
+magic tube, a crystal cylinder, closely set with sparkling emeralds, is
+revealed. And although so transparent, so apparently simple in structure
+that it does not seem possible for even the finest details to escape our
+search, yet almost as we watch it mystic changes appear. We see the bright
+green granules, impelled by an unseen force, separate and rearrange
+themselves in new formations. Strange outgrowths from the parent filament
+appear. The strange power we call "life," doubly mysterious when manifested
+in an organism so simple as this, so open to our search, seems to challenge
+us to discover its secret, and, armed with our glittering lenses and our
+flashing stands of exquisite workmanship, we search intently, but in vain.
+And yet _not_ in vain, for we are more than recompensed by the wondrous
+revelations beheld and the unalloyed pleasures enjoyed, through the study
+of even the unpretentious _Vaucheria_.
+
+The amplification of the objects in the engravings is about 80 diameters.
+
+       *       *       *       *       *
+
+
+
+
+JAPANESE CAMPHOR--ITS PREPARATION, EXPERIMENTS, AND ANALYSIS OF THE
+CAMPHOR OIL.
+
+[Footnote: From the Journal of the Society of Chemical Industry.]
+
+By H. OISHI. (Communicated by Kakamatsa.)
+
+
+LAURUS CAMPHORA, or "kusunoki," as it is called in Japan, grows mainly in
+those provinces in the islands Shikobu and Kinshin, which have the southern
+sea coast. It also grows abundantly in the province of Kishu.
+
+The amount of camphor varies according to the age of the tree. That of a
+hundred years old is tolerably rich in camphor. In order to extract the
+camphor, such a tree is selected; the trunk and large stems are cut into
+small pieces, and subjected to distillation with steam.
+
+An iron boiler of 3 feet in diameter is placed over a small furnace, the
+boiler being provided with an iron flange at the top. Over this flange a
+wooden tub is placed, which is somewhat narrowed at the top, being 1 foot 6
+inches in the upper, and 2 feet 10 inches in the lower diameter, and 4 feet
+in height. The tub has a false bottom for the passage of steam from the
+boiler beneath. The upper part of the tub is connected with a condensing
+apparatus by means of a wooden or bamboo pipe. The condenser is a flat
+rectangular wooden vessel, which is surrounded with another one containing
+cold water. Over the first is placed still another trough of the same
+dimensions, into which water is supplied to cool the vessel at the top.
+After the first trough has been filled with water, the latter flows into
+the next by means of a small pipe attached to it. In order to expose a
+large surface to the vapors, the condensing trough is fitted internally
+with a number of vertical partitions, which are open at alternate ends, so
+that the vapors may travel along the partitions in the trough from one end
+to the other. The boiler is filled with water, and 120 kilogrammes of
+chopped pieces of wood are introduced into the tub, which is then closed
+with a cover, cemented with clay, so as to make it air-tight. Firing is
+then begun; the steam passes into the tub, and thus carries the vapors of
+camphor and oil into the condenser, in which the camphor solidifies, and
+is mixed with the oil and condensed water. After twenty-four hours the
+charge is taken out from the tub, and new pieces of the wood are
+introduced, and distillation is conducted as before. The water in the
+boiler must be supplied from time to time. The exhausted wood is dried and
+used as fuel. The camphor and oil accumulated in the trough are taken out
+in five or ten days, and they are separated from each other by filtration.
+The yield of the camphor and oil varies greatly in different seasons. Thus
+much more solid camphor is obtained in winter than in summer, while the
+reverse is the case with the oil. In summer, from 120 kilogrammes of the
+wood 2.4 kilogrammes, or 2 per cent. of the solid camphor are obtained in
+one day, while in winter, from the same amount of the wood, 3 kilogrammes,
+or 2.5 per cent., of camphor are obtainable at the same time.
+
+The amount of the oil obtained in ten days, _i.e._, from 10 charges or
+1,200 kilogrammes of the wood, in summer is about 18 liters, while in
+winter it amounts only to 5-7 liters. The price of the solid camphor is
+at present about 1s. 1d. per kilo.
+
+The oil contains a considerable amount of camphor in solution, which is
+separated by a simple distillation and cooling. By this means about 20 per
+cent. of the camphor can be obtained from the oil. The author subjected the
+original oil to fractioned distillation, and examined different fractions
+separately. That part of the oil which distilled between 180°-185° O. was
+analyzed after repeated distillations. The following is the result:
+
+    Found.                Calculated as
+                          C_{10}H_{16}O.
+
+C = 78.87                     78.95
+H = 10.73                     10.52
+O = 10.40 (by difference)     10.52
+
+The composition thus nearly agrees with that of the ordinary camphor.
+
+The fraction between 178°-180° C., after three distillations, gave the
+following analytical result:
+
+C = 86.95
+H = 12.28
+    -----
+    99.23
+
+It appears from this result that the body is a hydrocarbon. The vapor
+density was then determined by V. Meyer's apparatus, and was found to be
+5.7 (air=1). The molecular weight of the compound is therefore 5.7 × 14.42
+× 2 = 164.4, which gives
+
+H = (164.4 × 12.28)/100 = 20.18
+                                   or C_{12}H_{20}
+C = (164.4 × 86.95)/100 = 11.81
+
+Hence it is a hydrocarbon of the terpene series, having the general formula
+C^{n}H^(2n-4). From the above experiments it seems to be probable that
+the camphor oil is a complicated mixture, consisting of hydrocarbons of
+terpene series, oxy-hydrocarbons isomeric with camphor, and other oxidized
+hydrocarbons.
+
+
+_Application of the Camphor Oil_.
+
+The distinguishing property of the camphor oil, that it dissolves many
+resins, and mixes with drying oils, finds its application for the
+preparation of varnish. The author has succeeded in preparing various
+varnishes with the camphor oil, mixed with different resins and oils.
+Lampblack was also prepared by the author, by subjecting the camphor oil to
+incomplete combustion. In this way from 100 c.c. of the oil, about 13
+grammes of soot of a very good quality were obtained. Soot or lampblack is
+a very important material in Japan for making inks, paints, etc. If the
+manufacture of lampblack from the cheap camphor oil is conducted on a large
+scale, it would no doubt be profitable. The following is the report on the
+amount of the annual production of camphor in the province of Tosa up to
+1880:
+
+    Amount of Camphor produced.   Total Cost.
+
+1877.......... 504,000 kins.... 65,520 yen.
+1878.......... 519,000   " .... 72,660  "
+1879.......... 292,890   " .... 74,481  "
+1880.......... 192,837   " .... 58,302  "
+
+(1 yen = 2_s_. 9_d_.)
+(1 kin = 1-1/3lb.)
+
+       *       *       *       *       *
+
+
+
+
+THE SUNSHINE RECORDER.
+
+
+McLeod's sunshine recorder consists of a camera fixed with its axis
+parallel to that of the earth, and with the lens northward. Opposite to the
+lens there is placed a round-bottomed flask, silvered inside. The solar
+rays reflected from this sphere pass through the lens, and act on the
+sensitive surface.
+
+[Illustration]
+
+The construction of the instrument is illustrated by the subjoined cut, A
+being a camera supported at an inclination of 56 degrees with the horizon,
+and B the spherical flask silvered inside, while at D is placed the
+ferro-prussiate paper destined to receive the solar impression. The dotted
+line, C, may represent the direction of the central solar ray at one
+particular time, and it is easy to see how the sunlight reflected from the
+flask always passes through the lens. As the sun moves (apparently) in a
+circle round the flask, the image formed by the lens moves round on the
+sensitive paper, forming an arc of a circle.
+
+Although it is obvious that any sensitive surface might be used in the
+McLeod sunshine recorder, the inventor prefers at present to use the
+ordinary ferro-prussiate paper as employed by engineers for copying
+tracings, as this paper can be kept for a considerable length of time
+without change, and the blue image is fixed by mere washing in water;
+another advantage is the circumstance that a scale or set of datum lines
+can be readily printed on the paper from an engraved block, and if the
+printed papers be made to register properly in the camera, the records
+obtained will show at a glance the time at which sunshine commenced and
+ceased.
+
+Instead of specially silvering a flask inside, it will be found convenient
+to make use of one of the silvered globes which are sold as Christmas tree
+ornaments.
+
+The sensitive fluid for preparing the ferro-prussiate paper is made as
+follows: One part by weight of ferricyanide of potassium (red prussiate) is
+dissolved in eight parts of water, and one part of ammonia-citrate of iron
+is added. This last addition must be made in the dark-room. A smooth-faced
+paper is now floated on the liquid and allowed to dry.--_Photo. News._
+
+       *       *       *       *       *
+
+
+
+
+BREAKING OF A WATER MAIN.
+
+
+In Boston, Mass., recently, at a point where two iron bridges, with stone
+abutments, are being built over the Boston and Albany Railroad tracks at
+Brookline Avenue, the main water pipe, which partially supplies the city
+with water, had to be raised, and while in that position a large stone
+which was being raised slipped upon the pipe and broke it. Immediately a
+stream of water fifteen feet high spurted out. Before the water could be
+shut off it had made a breach thirty feet long in the main line of track,
+so that the entire four tracks, sleepers, and roadbed at that point were
+washed completely away.
+
+       *       *       *       *       *
+
+
+A catalogue, containing brief notices of many important scientific papers
+heretofore published in the SUPPLEMENT, may be had gratis at this office.
+
+
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+
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+End of the Project Gutenberg EBook of Scientific American Supplement, No.
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+<html>
+<head>
+<meta name="generator" content="HTML Tidy, see www.w3.org">
+<meta http-equiv="Content-Type" content=
+"text/html; charset=ISO-8859-1">
+<title>The Project Gutenberg eBook of Scientific American
+Supplement, OCTOBER 25, 1884</title>
+<style type="text/css">
+<!--
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+img {border: 0;}
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+hr {text-align: center; width: 50%;}
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+<body>
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+
+<pre>
+
+The Project Gutenberg EBook of Scientific American Supplement, No. 460,
+October 25, 1884, by Various
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Scientific American Supplement, No. 460, October 25, 1884
+
+Author: Various
+
+Release Date: March 28, 2004 [EBook #11734]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK  SCIENTIFIC AMERICAN 460 ***
+
+
+
+
+Produced by Don Kretz, Juliet Sutherland, Charles Franks and the DP Team
+
+
+
+
+
+</pre>
+
+<p class="ctr"><a href="./illustrations/1a.png"><img src=
+"./illustrations/1a_th.jpg" alt=""></a></p>
+
+<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 460</h1>
+
+<h2>NEW YORK, OCTOBER 25, 1884</h2>
+
+<h4>Scientific American Supplement. Vol. XVIII, No. 460.</h4>
+
+<h4>Scientific American established 1845</h4>
+
+<h4>Scientific American Supplement, $5 a year.</h4>
+
+<h4>Scientific American and Supplement, $7 a year.</h4>
+
+<hr>
+<table summary="Contents" border="0" cellspacing="5">
+<tr>
+<th colspan="2">TABLE OF CONTENTS.</th>
+</tr>
+
+<tr>
+<td valign="top">I.</td>
+<td><a href="#1">CHEMISTRY. ETC.&mdash;Wolpert's Method of
+Estimating the Amount of Carbonic Acid in the Air.&mdash;7
+Figures.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#2">Japanese Camphor.&mdash;Its preparation,
+experiments, and analysis of the camphor oil.&mdash;By H.
+OISHI.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">II.</td>
+<td><a href="#3">ENGINEERING AND MECHANICS.&mdash;Links in the
+History of the Locomotive.&mdash;With two engravings of the
+Rocket.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#4">The Flow of Water through Turbines and Screw
+Propellers.&mdash;By ARTHUR RIGG.&mdash;Experimental
+researches.&mdash;Impact on level plate.&mdash;Impact and reaction
+in confined channels.&mdash;4 figures.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#5">Improved Textile Machinery.&mdash;The Textile
+Exhibition at Islington.&mdash;5 figures.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#6">Endless Rope Haulage.&mdash;2 figures.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">III.</td>
+<td><a href="#7">TECHNOLOGY.&mdash;A Reliable Water
+Filter.&mdash;With engraving.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#8">Simple Devices for Distilling Water.&mdash;4
+figures.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#9">Improved Fire Damp Detecter.&mdash;With full
+description and engraving.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#10">Camera Attachment for Paper Photo
+Negatives.&mdash;2 figures.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#11">Instantaneous Photo Shutter.&mdash;1 figure.</a>
+</td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#12">Sulphurous Acid.&mdash;Easy method of preparation
+for photographic purposes.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">IV.</td>
+<td><a href="#13">PHYSICS. ELECTRICITY, ETC.&mdash;Steps toward a
+Kinetic Theory of Matter.&mdash;Address by Sir Wm. THOMSON at the
+Montreal meeting of the British Association.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#14">Application of Electricity to Tramways.&mdash;By
+M. HOLROYD SMITH.&mdash;7 figures.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#15">The Sunshine Recorder.&mdash;1 figure.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">V.</td>
+<td><a href="#16">ARCHITECTURE AND ART.&mdash;The National Monument
+at Rome.&mdash;With full page engraving.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#17">On the Evolution of Forms of Art.&mdash;From a
+paper by Prof. JACOBSTHAL.&mdash;Plant Forms the archetypes of
+cashmere patterns.&mdash;Ornamental representations of plants of
+two kinds.&mdash;Architectural forms of different ages.&mdash;20
+figures.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">VI.</td>
+<td><a href="#18">NATURAL HISTORY.&mdash;The Latest Knowledge about
+Gapes.&mdash;How to keep poultry free from them.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#19">The Voyage of the Vettor Pisani.&mdash;Shark
+fishing In the Gulf of Panama.&mdash;Capture of Rhinodon typicus,
+the largest fish in existence.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">VII.</td>
+<td><a href="#20">HORTICULTURE, ETC.&mdash;The Proper Time for
+Cutting Timber.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#21">Raising Ferns from Spores.&mdash;1 figure.</a>
+</td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#22">The Life History of Vaucheria.&mdash;Growth of
+alga vaucheria under the microscope.&mdash;4 figures.</a> </td>
+</tr>
+
+<tr>
+<td valign="top">VIII.</td>
+<td><a href="#23">MISCELLANEOUS.&mdash;Fires in London and New
+York.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#24">The Greely Arctic Expedition.&mdash;With
+engraving.</a> </td>
+</tr>
+
+<tr>
+<td></td>
+<td><a href="#25">The Nile Expedition.&mdash;1 figure.</a> </td>
+</tr>
+</table>
+
+<hr>
+<p><a name="3"></a></p>
+
+<h2>LINKS IN THE HISTORY OF THE LOCOMOTIVE.</h2>
+
+<p>It is, perhaps, more difficult to write accurate history than
+anything else, and this is true not only of nations, kings,
+politicians, or wars, but of events and things witnessed or called
+into existence in every-day life. In <i>The Engineer</i> for
+September 17, 1880, we did our best to place a true statement of
+the facts concerning the Rocket before our readers. In many
+respects this was the most remarkable steam engine ever built, and
+about it there ought to be no difficulty, one would imagine, in
+arriving at the truth. It was for a considerable period the
+cynosure of all eyes. Engineers all over the world were interested
+in its performance. Drawings were made of it; accounts were written
+of it, descriptions of it abounded. Little more than half a century
+has elapsed since it startled the world by its performance at
+Rainhill, and yet it is not too much to say that the
+truth&mdash;the whole truth, that is to say&mdash;can never now be
+written. We are, however, able to put some facts before our readers
+now which have never before been published, which are sufficiently
+startling, and while supplying a missing link in the history of the
+locomotive, go far to show that much that has hitherto been held to
+be true is not true at all.</p>
+
+<p>When the Liverpool and Manchester Railway was opened on the 15th
+of September, 1830, among those present was James Nasmyth,
+subsequently the inventor of the steam hammer. Mr. Nasmyth was a
+good freehand draughtsman, and he sketched the Rocket as it stood
+on the line. The sketch is still in existence. Mr. Nasmyth has
+placed this sketch at our disposal, thus earning the gratitude of
+our readers, and we have reproduced as nearly as possible, but to a
+somewhat enlarged scale, this invaluable link in the history of the
+locomotive. Mr. Nasmyth writes concerning it, July 26, 1884: "This
+slight and hasty sketch of the Rocket was made the day before the
+opening of the Manchester and Liverpool Railway, September 12,
+1830. I availed myself of the opportunity of a short pause in the
+experimental runs with the Rocket, of three or four miles between
+Liverpool and Rainhill, George Stephenson acting as engine driver
+and his son Robert as stoker. The limited time I had for making my
+sketch prevented me from making a more elaborate one, but such as
+it is, all the important and characteristic details are given; but
+the pencil lines, after the lapse of fifty-four years, have become
+somewhat indistinct." The pencil drawing, more than fifty years
+old, has become so faint that its reproduction has become a
+difficult task. Enough remains, however, to show very clearly what
+manner of engine this Rocket was. For the sake of comparison we
+reproduce an engraving of the Rocket of 1829. A glance will show
+that an astonishing transformation had taken place in the eleven
+months which had elapsed between the Rainhill trials and the
+opening of the Liverpool and Manchester Railway. We may indicate a
+few of the alterations. In 1829 the cylinders were set at a steep
+angle; in 1830 they were nearly horizontal. In 1829 the driving
+wheels were of wood; in 1830 they were of cast iron. In 1829 there
+was no smoke-box proper, and a towering chimney; in 1830 there was
+a smoke-box and a comparatively short chimney. In 1829 a cask and a
+truck constituted the tender; in 1830 there was a neatly designed
+tender, not very different in style from that still in use on the
+Great Western broad gauge. All these things may perhaps be termed
+concomitants, or changes in detail. But there is a radical
+difference yet to be considered. In 1829 the fire-box was a kind of
+separate chamber tacked on to the back of the barrel of the boiler,
+and communicating with it by three tubes; one on each side united
+the water spaces, and one at the top the steam spaces. In 1830 all
+this had disappeared, and we find in Mr. Nasmyth's sketch a regular
+fire-box, such as is used to this moment. In one word, the Rocket
+of 1829 is different from the Rocket of 1830 in almost every
+conceivable respect; and we are driven perforce to the conclusion
+that the Rocket of 1829 <i>never worked at all on the Liverpool and
+Manchester Railway; the engine of 1830 was an entirely new
+engine</i>. We see no possible way of escaping from this
+conclusion. The most that can be said against it is that the engine
+underwent many alterations. The alterations must, however, have
+been so numerous that they were tantamount to the construction of a
+new engine. It is difficult, indeed, to see what part of the old
+engine could exist in the new one; some plates of the boiler shell
+might, perhaps, have been retained, but we doubt it. It may,
+perhaps, disturb some hitherto well rooted beliefs to say so, but
+it seems to us indisputable that the Rocket of 1829 and 1830 were
+totally different engines.</p>
+
+<p class="ctr"><a href="./illustrations/1b.png"><img src=
+"./illustrations/1b_th.jpg" alt=
+" FIG. 1. THE ROCKET, 1829. THE ROCKET, 1830."></a></p>
+
+<p class="ctr">FIG. 1. THE ROCKET, 1829. THE ROCKET, 1830.</p>
+
+<p>Our engraving, Fig. 1, is copied from a drawing made by Mr.
+Phipps, M.I.C.E., who was employed by Messrs. Stephenson to compile
+a drawing of the Rocket from such drawings and documents as could
+be found. This gentleman had made the original drawings of the
+Rocket of 1829, under Messrs. G. &amp; R. Stephenson's direction.
+Mr. Phipps is quite silent about the history of the engine during
+the eleven months between the Rainhill trials and the opening of
+the railway. In this respect he is like every one else. This period
+is a perfect blank. It is assumed that from Rainhill the engine
+went back to Messrs. Stephenson's works; but there is nothing on
+the subject in print, so far as we are aware. Mr. G.R. Stephenson
+lent us in 1880 a working model of the Rocket. An engraving of this
+will be found in <i>The Engineer</i> for September 17, 1880. The
+difference between it and the engraving below, prepared from Mr.
+Phipps' drawing, is, it will be seen, very small&mdash;one of
+proportions more than anything else. Mr. Stephenson says of his
+model: "I can say that it is a very fair representation of what the
+engine was before she was altered." Hitherto it has always been
+taken for granted that the alteration consisted mainly in reducing
+the angle at which the cylinders were set. The Nasmyth drawing
+alters the whole aspect of the question, and we are now left to
+speculate as to what became of the original Rocket. We are told
+that after "it" left the railway it was employed by Lord Dundonald
+to supply steam to a rotary engine; then it propelled a steamboat;
+next it drove small machinery in a shop in Manchester; then it was
+employed in a brickyard; eventually it was purchased as a curiosity
+by Mr. Thomson, of Kirkhouse, near Carlisle, who sent it to Messrs.
+Stephenson to take care of. With them it remained for years. Then
+Messrs. Stephenson put it into something like its original shape,
+and it went to South Kensington Museum, where "it" is now. The
+question is, What engine is this? Was it the Rocket of 1829 or the
+Rocket of 1830, or neither? It could not be the last, as will be
+understood from Mr. Nasmyth's drawing; if we bear in mind that the
+so-called fire-box on the South Kensington engine is only a sham
+made of thin sheet iron without water space, while the fire-box
+shown in Mr. Nasmyth's engine is an integral part of the whole,
+which could not have been cut off. That is to say, Messrs.
+Stephenson, in getting the engine put in order for the Patent
+Office Museum, certainly did not cut off the fire-box shown in Mr.
+Nasmyth's sketch, and replace it with the sham box now on the
+boiler. If our readers will turn to our impression for the 30th of
+June, 1876, they will find a very accurate engraving of the South
+Kensington engine, which they can compare with Mr. Nasmyth's
+sketch, and not fail to perceive that the differences are
+radical.</p>
+
+<p>In "Wood on Railroads," second edition, 1832, page 377, we are
+told that "after those experiments"&mdash;the Rainhill
+trials&mdash;"were concluded, the Novelty underwent considerable
+alterations;" and on page 399, "Mr. Stephenson had also improved
+the working of the Rocket engine, and by applying the steam more
+powerfully in the chimney to increase the draught, was enabled to
+raise a much greater quantity of steam than before." Nothing is
+said as to where the new experiments took place, nor their precise
+date. But it seems that the Meteor and the Arrow&mdash;Stephenson
+engines&mdash;were tried at the same time; and this is really the
+only hint Wood gives as to what was done to the Rocket between the
+6th of October, 1829, and the 15th of September, 1830.</p>
+
+<p>There are men still alive who no doubt could clear up the
+question at issue, and it is much to be hoped that they will do so.
+As the matter now stands, it will be seen that we do not so much
+question that the Rocket in South Kensington Museum is, in part
+perhaps, the original Rocket of Rainhill celebrity, as that it ever
+ran in regular service on the Liverpool and Manchester Railway.
+Yet, if not, then we may ask, what became of the Rocket of 1830? It
+is not at all improbable that the first Rocket was cast on one
+side, until it was bought by Lord Dundonald, and that its history
+is set out with fair accuracy above. But the Rocket of the
+Manchester and Liverpool Railway is hardly less worthy of attention
+than its immediate predecessor, and concerning it information is
+needed. Any scrap of information, however apparently trifling, that
+can be thrown on this subject by our readers will be highly valued,
+and given an appropriate place in our pages.&mdash;<i>The
+Engineer</i>.</p>
+
+<hr>
+<p>The largest grain elevator in the world, says the <i>Nashville
+American</i>, is that just constructed at Newport News under the
+auspices of the Chesapeake &amp; Ohio Railway Co. It is 90 ft.
+wide, 386 ft. long, and about 164 ft. high, with engine and boiler
+rooms 40 &times; 100 ft. and 40 ft. high. In its construction there
+were used about 3,000 piles, 100,000 ft. of white-oak timber,
+82,000 cu. ft. of stone, 800,000 brick, 6,000,000 ft. of pine and
+spruce lumber, 4,500 kegs of nails, 6 large boilers, 2 large
+engines, 200 tons of machinery, 20 large hopper-scales, and 17,200
+ft. of rubber belts, from 8 to 48 in. wide and 50 to 1,700 ft.
+long; in addition, there were 8,000 elevator buckets, and other
+material. The storage capacity is 1,600,000 bushels, with a
+receiving capacity of 30,000, and a shipping capacity of 20,000
+bushels per hour.</p>
+
+<hr>
+<p><a name="4"></a></p>
+
+<h2>THE FLOW OF WATER THROUGH TURBINES AND SCREW PROPELLERS.<a
+name="FNanchor_1"></a><a href="#Footnote_1"><sup>1</sup></a></h2>
+
+<h3>By Mr. ARTHUR RIGG, C.E.</h3>
+
+<p>Literature relating to turbines probably stands unrivaled among
+all that concerns questions of hydraulic engineering, not so much
+in its voluminous character as in the extent to which purely
+theoretical writers have ignored facts, or practical writers have
+relied upon empirical rules rather than upon any sound theory. In
+relation to this view, it may suffice to note that theoretical
+deductions have frequently been based upon a generalization that
+"streams of water must enter the buckets of a turbine without
+shock, and leave them without velocity." Both these assumed
+conditions are misleading, and it is now well known that in every
+good turbine both are carefully disobeyed. So-called practical
+writers, as a rule, fail to give much useful information, and their
+task seems rather in praise of one description of turbine above
+another. But generally, it is of no consequence whatever how a
+stream of water may be led through the buckets of any form of
+turbine, so long as its velocity gradually becomes reduced to the
+smallest amount that will carry it freely clear of the machine.</p>
+
+<p>The character of theoretical information imparted by some
+<i>Chicago Journal of Commerce</i>, dated 20th February, 1884.
+There we are informed that "the height of the fall is one of the
+most important considerations, as the same stream of water will
+furnish five times the horse power at ten ft. that it will at five
+ft. fall." By general consent twice two are four, but it has been
+reserved for this imaginative writer to make the useful discovery
+that sometimes twice two are ten. Not until after the translation
+of Captain Morris' work on turbines by Mr. E. Morris in 1844, was
+attention in America directed to the advantages which these motors
+possessed over the gravity wheels then in use. A duty of 75 per
+cent. was then obtained, and a further study of the subject by a
+most acute and practical engineer, Mr. Boyden, led to various
+improvements upon Mr. Fauneyron's model, by which his experiments
+indicated the high duty of 88 per cent. The most conspicuous
+addition made by Mr. Boyden was the diffuser. The ingenious
+contrivance had the effect of transforming part of whatever
+velocity remained in the stream after passing out of a turbine into
+an atmospheric pressure, by which the corresponding lost head
+became effective, and added about 3 per cent. to the duty obtained.
+It may be worth noticing that, by an accidental application of
+these principles to some inward flow turbines, there is obtained
+most, if not all, of whatever advantage they are supposed to
+possess, but oddly enough this genuine advantage is never mentioned
+by any of the writers who are interested in their introduction or
+sale. The well-known experiments of Mr. James B. Francis in 1857,
+and his elaborate report, gave to hydraulic engineers a vast store
+of useful data, and since that period much progress has been made
+in the construction of turbines, and literature on the subject has
+become very complete.</p>
+
+<p>In the limits of a short paper it is impossible to do justice to
+more than one aspect of the considerations relating to turbines,
+and it is now proposed to bring before the Mechanical Section of
+the British Association some conclusions drawn from the behavior of
+jets of water discharged under pressure, more particularly in the
+hope that, as water power is extremely abundant in Canada, any
+remarks relating to the subject may not fail to prove
+interesting.</p>
+
+<p>Between the action of turbines and that of screw propellers
+exists an exact parallelism, although in one case water imparts
+motion to the buckets of a turbine, while in the other case blades
+of a screw give spiral movement to a column of water driven aft
+from the vessel it propels forward. Turbines have been driven
+sometimes by impact alone, sometimes by reaction above, though
+generally by a combination of impact and reaction, and it is by the
+last named system that the best results are now known to be
+obtained.</p>
+
+<p>The ordinary paddles of a steamer impel a mass of water
+horizontally backward by impact alone, but screw propellers use
+reaction somewhat disguised, and only to a limited extent. The full
+use and advantages of reaction for screw propellers were not
+generally known until after the publication of papers by the
+present writer in the "Proceedings" of the Institution of Naval
+Architects for 1867 and 1868, and more fully in the "Transactions"
+of the Society of Engineers for 1868. Since that time, by the
+author of these investigations then described, by the English
+Admiralty, and by private firms, further experiments have been
+carried out, some on a considerable scale, and all corroborative of
+the results published in 1868. But nothing further has been done in
+utilizing these discoveries until the recent exigencies of modern
+naval warfare have led foreign nations to place a high value upon
+speed. Some makers of torpedo boats have thus been induced to
+slacken the trammels of an older theory and to apply a somewhat
+incomplete form of the author's reaction propeller for gaining some
+portion of the notable performance of these hornets of the deep.
+Just as in turbines a combination of impact and reaction produces
+the maximum practical result, so in screw propellers does a
+corresponding gain accompany the same construction.</p>
+
+<p class="ctr"><img src="./illustrations/2a.png" alt=
+" FIG. 1."></p>
+
+<p class="ctr">FIG. 1.</p>
+
+<p class="ctr"><img src="./illustrations/2b.png" alt=
+" FIG. 2."></p>
+
+<p class="ctr">FIG. 2.</p>
+
+<p><i>Turbines</i>.&mdash;While studying those effects produced by
+jets of water impinging upon plain or concave surfaces
+corresponding to buckets of turbines, it simplifies matters to
+separate these results due to impact from others due to reaction.
+And it will be well at the outset to draw a distinction between the
+nature of these two pressures, and to remind ourselves of the laws
+which lie at the root and govern the whole question under present
+consideration. Water obeys the laws of gravity, exactly like every
+other body; and the velocity with which any quantity may be falling
+is an expression of the full amount of work it contains. By a
+sufficiently accurate practical rule this velocity is eight times
+the square root of the head or vertical column measured in feet.
+Velocity per second = 8 sqrt (head in feet), therefore, for a head
+of 100 ft. as an example, V = 8 sqrt (100) = 80 ft. per second. The
+graphic method of showing velocities or pressures has many
+advantages, and is used in all the following diagrams. Beginning
+with purely theoretical considerations, we must first recollect
+that there is no such thing as absolute motion. All movements are
+relative to something else, and what we have to do with a stream of
+water in a turbine is to reduce its velocity relatively to the
+earth, quite a different thing to its velocity in relation to the
+turbine; for while the one may be zero, the other may be anything
+we please. ABCD in Fig. 1 represents a parallelogram of velocities,
+wherein AC gives the direction of a jet of water starting at A, and
+arriving at C at the end of one second or any other division of
+time. At a scale of 1/40 in. to 1 ft., AC represents 80 ft., the
+fall due to 100 ft. head, or at a scale of 1 in. to 1 ft., AC gives
+2 ft., or the distance traveled by the same stream in 1/40 of a
+second. The velocity AC may be resolved into two others, namely, AB
+and AD, or BC, which are found to be 69.28 ft. and 40 ft.
+respectively, when the angle BAC&mdash;generally called <i>x</i> in
+treatises on turbines&mdash;is 30 deg. If, however, AC is taken at
+2 ft., then A B will be found = 20.78 in., and BC = 12 in. for a
+time of 1/40 or 0.025 of a second. Supposing now a flat plate, BC =
+12 in. wide move from DA to CB during 0.025 second, it will be
+readily seen that a drop of water starting from A will have arrived
+at C in 0.025 second, having been flowing along the surface BC from
+B to C without either friction or loss of velocity. If now, instead
+of a straight plate, BC, we substitute one having a concave
+surface, such as BK in Fig. 2, it will be found necessary to move
+it from A to L in 0.025 second, in order to allow a stream to
+arrive at C, that is K, without, in transit, friction or loss of
+velocity. This concave surface may represent one bucket of a
+turbine. Supposing now a resistance to be applied to that it can
+only move from A to B instead of to L. Then, as we have already
+resolved the velocity A C into AB and BC, so far as the former (AB)
+is concerned, no alteration occurs whether BK be straight or
+curved. But the other portion, BC, pressing vertically against the
+concave surface, BK, becomes gradually diminished in its velocity
+in relation to the earth, and produces and effect known as
+"reaction." A combined operation of impact and reaction occurs by
+further diminishing the distance which the bucket is allowed to
+travel, as, for examples, to EF. Here the jet is impelled against
+the lower edge of the bucket, B, and gives a pressure by its
+impact; then following the curve BK, with a diminishing velocity,
+it is finally discharged at K, retaining only sufficient movement
+to carry the water clear out of the machine. Thus far we have
+considered the movement of jets and buckets along AB as straight
+lines, but this can only occur, so far as buckets are concerned,
+when their radius in infinite. In practice these latter movements
+are always curves of more or less complicated form, which effect a
+considerable modification in the forms of buckets, etc., but not in
+the general principles, and it is the duty of the designer of any
+form of turbine to give this consideration its due importance.
+Having thus cleared away any ambiguity from the terms "impact," and
+"reaction," and shown how they can act independently or together,
+we shall be able to follow the course and behavior of streams in a
+turbine, and by treating their effects as arising from two separate
+causes, we shall be able to regard the problem without that
+inevitable confusion which arises when they are considered as
+acting conjointly. Turbines, though driven by vast volumes of
+water, are in reality impelled by countless isolated jets, or
+streams, all acting together, and a clear understanding of the
+behavior of any one of these facilitates and concludes a solution
+of the whole problem.</p>
+
+<p><i>Experimental researches</i>.&mdash;All experiments referred
+to in this paper were made by jets of water under an actual
+vertical head of 45 ft., but as the supply came through a
+considerable length of &frac12; in. bore lead piping, and many
+bends, a large and constant loss occurred through friction and
+bends, so that the actual working head was only known by measuring
+the velocity of discharge. This was easily done by allowing all the
+water to flow into a tank of known capacity. The stop cock had a
+clear circular passage through it, and two different jets were
+used. One oblong measured 0.5 in. by 0.15 in., giving an area of
+0.075 square inch. The other jet was circular, and just so much
+larger than &frac14; in. to be 0.05 of a square inch area, and the
+stream flowed with a velocity of 40 ft. per second, corresponding
+to a head of 25 ft. Either nozzle could be attached to the same
+universal joint, and directed at any desired inclination upon the
+horizontal surface of a special well-adjusted compound weighing
+machine, or into various bent tubes and other attachments, so that
+all pressures, whether vertical or horizontal, could be accurately
+ascertained and reduced to the unit, which was the quarter of an
+ounce. The vertical component <i>p</i> of any pressure P may be
+ascertained by the formula&mdash;</p>
+
+<pre>
+<i>p</i> = P sin alpha,
+</pre>
+
+<p>where alpha is the angle made by a jet against a surface; and in
+order to test the accuracy of the simple machinery employed for
+these researches, the oblong jet which gave 71 unit when impinging
+vertically upon a circular plate, was directed at 60 deg. and 45
+deg. thereon, with results shown in Table I., and these, it will be
+observed, are sufficiently close to theory to warrant reliance
+being placed on data obtained from the simple weighing machinery
+used in the experiment.</p>
+
+<pre>
+                 <i>Table I.&mdash;Impact on Level Plate.</i>
+--------------+--------------------+----------+----------+----------
+              | Inclination of jet |          |          |
+  Distance.   | to the horizonal.  |  90 deg. |  60 deg. |  45 deg.
+--------------+--------------------+----------+----------+----------
+              |                    | Pressure | Pressure | Pressure
+              |                    |          |          |
+            / |  Experiment    \   |        / |   61.00  |   49.00
+ 1&frac12; in.    &lt;  |                 &gt;  | 71.00 &lt;  |          |
+            \ |  Theory        /   |        \ |   61.48  |   50.10
+              |                    |          |          |
+              |                    |          |          |
+            / |  Experiment    \   |        / |   55.00  |   45.00
+ 1 in.     &lt;  |                 &gt;  | 63.00 &lt;  |          |
+            \ |  Theory        /   |        \ |   54.00  |   45.00
+              |                    |          |          |
+--------------+--------------------+----------+----------+----------
+             In each case the unit of pressure is &frac14; oz.
+</pre>
+
+<p>In the first trial there was a distance of 1&frac12; in. between
+the jet and point of its contact with the plate, while in the
+second trial this space was diminished to &frac12; in. It will be
+noticed that as this distance increases we have augmented
+pressures, and these are not due, as might be supposed, to increase
+of head, which is practically nothing, but they are due to the
+recoil of a portion of the stream, which occurs increasingly as it
+becomes more and more broken up. These alterations in pressure can
+only be eliminated when care is taken to measure that only due to
+impact, without at the same time adding the effect of an imperfect
+reaction. Any stream that can run off at all points from a smooth
+surface gives the minimum of pressure thereon, for then the least
+resistance is offered to the destruction of the vertical element of
+its velocity, but this freedom becomes lost when a stream is
+diverted into a confined channel. As pressure is an indication and
+measure of lost velocity, we may then reasonably look for greater
+pressure on the scale when a stream is confined after impact than
+when it discharges freely in every direction. Experimentally this
+is shown to be the case, for when the same oblong jet, discharged
+under the same conditions, impinged vertically upon a smooth plate,
+and gave a pressure of 71 units, gave 87 units when discharged into
+a confined right-angled channel. This result emphasizes the
+necessity for confining streams of water whenever it is desired to
+receive the greatest pressure by arresting their velocity. Such
+streams will always endeavor to escape in the directions of least
+resistance, and, therefore, in a turbine means should be provided
+to prevent any lateral deviation of the streams while passing
+through their buckets. So with screw propellers the great mass of
+surrounding water may be regarded as acting like a channel with
+elastic sides, which permits the area enlarging as the velocity of
+a current passing diminishes. The experiments thus far described
+have been made with jets of an oblong shape, and they give results
+differing in some degree from those obtained with circular jets.
+Yet as the general conclusions from both are found the same, it
+will avoid unnecessary prolixity by using the data from experiments
+made with a circular jet of 0.05 square inch area, discharging a
+stream at the rate of 40 ft. per second. This amounts to 52 lb. of
+water per minute with an available head of 25 ft., or 1,300
+foot-pounds per minute. The tubes which received and directed the
+course of this jet were generally of lead, having a perfectly
+smooth internal surface, for it was found that with a rougher
+surface the flow of water is retarded, and changes occur in the
+data obtained. Any stream having its course changed presses against
+the body causing such change, this pressure increasing in
+proportion to the angle through which the change is made, and also
+according to the radius of a curve around which it flows. This fact
+has long been known to hydraulic engineers, and formul&aelig; exist
+by which such pressures can be determined; nevertheless, it will be
+useful to study these relations from a somewhat different point of
+view than has been hitherto adopted, more particularly as they bear
+upon the construction of screw propellers and turbines; and by
+directing the stream, AB, Fig. 3, vertically into a tube 3/8 in.
+internal diameter and bent so as to turn the jet horizontally, and
+placing the whole arrangement upon a compound weighing machine, it
+is easy to ascertain the downward pressure, AB, due to impact, and
+the horizontal pressures, CB, due to reaction. In theoretical
+investigations it may be convenient to assume both these pressures
+exactly equal, and this has been done in the paper "On Screw
+Propellers" already referred to; but this brings in an error of no
+importance so far as general principles are involved, but one which
+destroys much of the value such researches might, otherwise possess
+for those who are engaged in the practical construction of screw
+propellers or turbines. The downward impact pressure, AB, is always
+somewhat greater than the horizontal reaction, BC, and any
+proportions between these two can only be accurately ascertained by
+trials. In these particular experiments the jet of water flowed 40
+ft. per second through an orifice of 0.05 square inch area, and in
+every case its course was bent to a right angle. The pressures for
+impact and reaction were weighed coincidently, with results given
+by columns 1 and 2, Table II.</p>
+
+<p class="ctr"><a href="./illustrations/2c.png"><img src=
+"./illustrations/2c_th.jpg" alt=" FIG. 3"></a></p>
+
+<p class="ctr">FIG. 3</p>
+
+<p class="ctr"><a href="./illustrations/2d.png"><img src=
+"./illustrations/2d_th.jpg" alt=" FIG. 4"></a></p>
+
+<p class="ctr">FIG. 4</p>
+
+<pre>
+<i>Table II.&mdash;Impact and Reaction in Confined Channels.</i>
+
+-----------------------------+-------+---------+----------+-------
+Number of column.            |   1   |    2    |    3     |   4
+-----------------------------+-------+---------+----------+-------
+Description of experiments.  |Impact.|Reaction.|Resultant.| Angles
+                             |       |         |          |  ABS.
+-----------------------------+-------+---------+----------+-------
+Smooth London tube, 1&frac34; in.   |  71   |   62    |  94.25   |   49&deg;
+  mean radius.               |       |         |          |
+                             |       |         |          |
+Rough wrought iron tube,     |  78   |   52    |  98.75   |  56.5&deg;
+  1&frac34; in.                     |       |         |          |
+                             |       |         |          |
+Smooth leaden tube bent to a |  71   |   40    |  81.5    |   60
+  sharp right angle.         |       |         |          |
+-----------------------------+-------+---------+----------+------
+</pre>
+
+<p>The third column is obtained by constructing a parallelogram of
+forces, where impact and reaction form the measures of opposing
+sides, and it furnishes the resultant due to both forces. The
+fourth column gives the inclination ABS, at which the line of
+impact must incline toward a plane surface RS, Fig. 3, so as to
+produce this maximum resultant perpendicularly upon it; as the
+resultant given in column 3 indicates the full practical effect of
+impact and reaction. When a stream has its direction changed to one
+at right angles to its original course, and as such a changed
+direction is all that can be hoped for by ordinary screw
+propellers, the figures in column 3 should bear some relationship
+to such cases. Therefore, it becomes an inquiry of some interest as
+to what angle of impact has been found best in those screw
+propellers which have given the best results in practical work.
+Taking one of the most improved propellers made by the late Mr.
+Robert Griffiths, its blades do not conform to the lines of a true
+screw, but it is an oblique paddle, where the acting portions of
+its blades were set at 48 deg. to the keel of the ship or 42 deg.
+to the plane of rotation. Again, taking a screw tug boat on the
+river Thames, with blades of a totally different form to those used
+by Mr. Griffiths, we still find them set at the same angle, namely,
+48 deg. to the keel or 42 deg. to the plane of rotation. An
+examination of other screws tends only to confirm these figures,
+and they justify the conclusion that the inclinations of blades
+found out by practice ought to be arrived at, or at any rate
+approached, by any sound and reliable theory; and that blades of
+whatever form must not transgress far from this inclination if they
+are to develop any considerable efficiency. Indeed, many favorable
+results obtained by propellers are not due to their peculiarities,
+but only to the fact that they have been made with an inclination
+of blade not far from 42 deg. to the plan of rotation. Referring to
+column 4, and accepting the case of water flowing through a smooth
+tube as analogous to that of a current flowing within a large body
+of water, it appears that the inclination necessary to give the
+highest resultant pressure is an angle of 49 deg., and this
+corresponds closely enough with the angle which practical
+constructors of screw propellers have found to give the best
+results. Until, therefore, we can deal with currents after they
+have been discharged from the blades of a propeller, it seems
+unlikely that anything can be done by alterations in the pitch of a
+propeller. So far as concerns theory, the older turbines were
+restricted to such imperfect results of impact and reaction as
+might be obtained by turning a stream at right angles to its
+original course; and the more scientific of modern turbine
+constructors may fairly claim credit for an innovation by which
+practice gave better results than theory seemed to warrant; and the
+consideration of this aspect of the question will form the
+concluding subject of the present paper. Referring again to Fig. 3,
+when a current passes round such a curve as the quadrant of a
+circle, its horizontal reaction appears as a pressure along
+<i>c</i> B, which is the result of the natural integration of all
+the horizontal components of pressures, all of which act
+perpendicularly to each element of the concave surface along which
+the current flows. If, now, we add another quadrant of a circle to
+the curve, and so turn the stream through two right angles, or 180
+deg., as shown by Fig. 4, then such a complete reversal of the
+original direction represents the carrying of it back again to the
+highest point; it means the entire destruction of its velocity, and
+it gives the maximum pressure obtainable from a jet of water
+impinging upon a surface of any form whatsoever. The reaction
+noticed in Fig. 3 as acting along <i>c</i> B is now confronted by
+an impact of the now horizontal stream as it is turned round the
+second 90 deg. of curvature, and reacts also vertically downward.
+It would almost seem as if the first reaction from B to F should be
+exactly neutralized by the second impact from F to D. But such is
+not the case, as experiment shows an excess of the second impact
+over the first reaction amounting to six units, and shows also that
+the behavior of the stream through its second quadrant is precisely
+similar in kind to the first, only less in degree. Also the impact
+takes place vertically in one case and horizontally in the other.
+The total downward pressure given by the stream when turned 180
+deg. is found by experiment thus: Total impact and reaction from
+180 deg. change in direction of current = 132 units; and by
+deducting the impact 71 units, as previously measured, the new
+reaction corresponds with an increase of 61 units above the first
+impact. It also shows an increase of 37.75 units above the greatest
+resultant obtained by the same stream turned through 90 deg. only.
+Therefore, in designing a screw propeller or turbine, it would seem
+from these experiments desirable to aim at changing the direction
+of the stream, so far as possible, into one at 180 deg. to its
+original course, and it is by carrying out this view, so far as the
+necessities of construction will permit, that the scientifically
+designed modern turbine has attained to that prominence which it
+holds at present over all hydraulic motors. Much more might be
+written to extend and amplify the conclusions that can be drawn
+from the experiments described in the present paper, and from many
+others made by the writer, but the exigencies of time and your
+patience alike preclude further consideration of this interesting
+and important subject.</p>
+
+<a name="Footnote_1"></a><a href="#FNanchor_1">[1]</a>
+
+<div class="note">Paper read before the British Association at
+Montreal.</div>
+
+<hr>
+<p><a name="5"></a></p>
+
+<h2>IMPROVED TEXTILE MACHINERY.</h2>
+
+<p class="ctr"><a href="./illustrations/3a.png"><img src=
+"./illustrations/3a_th.jpg" alt=
+" THE TEXTILE EXHIBITION, ISLINGTON."></a></p>
+
+<p class="ctr">THE TEXTILE EXHIBITION, ISLINGTON.</p>
+
+<p>In the recent textile exhibition at Islington, one of the most
+extensive exhibits was that, of Messrs. James Farmer and Sons, of
+Salford. The exhibit consists of a Universal calender, drying
+machines, patent creasing, measuring, and marking machines, and
+apparatus for bleaching, washing, chloring, scouring, soaping,
+dunging, and dyeing woven fabrics. The purpose of the Universal
+calender is, says the <i>Engineer</i>, to enable limited quantities
+of goods to be finished in various ways without requiring different
+machines. The machine consists of suitable framing, to which is
+attached all the requisite stave rails, batching apparatus,
+compound levers, top and bottom adjusting screws, and level setting
+down gear, also Stanley roller with all its adjustments. It is
+furthermore supplied with chasing arrangement and four bowls; the
+bottom one is of cast iron, with wrought iron center; the next is
+of paper or cotton; the third of chilled iron fitted for heating by
+steam or gas, and the top of paper or cotton. By this machine are
+given such finishes as are known as "chasing finish" when the
+thready surface is wanted; "frictioning," or what is termed
+"glazing finish," "swigging finish," and "embossing finish;" the
+later is done by substituting a steel or copper engraved roller in
+place of the friction bowl. This machine is also made to I produce
+the "Moire luster" finish. The drying machine consists of nineteen
+cylinders, arranged with stave rails and plaiting down apparatus.
+These cylinders are driven by bevel wheels, so that each one is
+independent of its neighbor, and should any accident occur to one
+or more of the cylinders or wheels, the remaining ones can be run
+until a favorable opportunity arrives to repair the damage. A small
+separate double cylinder diagonal engine is fitted to this machine,
+the speed of which can be adjusted for any texture of cloth, and
+being of the design it is, will start at once on steam being turned
+one. The machine cylinders are rolled by a special machine for that
+purpose, and are perfectly true on the face. Their insides are
+fitted with patent buckets, which remove all the condensed water.
+In the machine exhibited, which is designed for the bleaching,
+washing, chloring, and dyeing, the cloth is supported by hollow
+metallic cylinders perforated with holes and corrugated to allow
+the liquor used to pass freely through as much of the cloth as
+possible; the open ends of the cylinders are so arranged that
+nearly all of their area is open to the action of the pump. The
+liquor, which is drawn through the cloth into the inside of the
+cylinders by the centrifugal pumps, is discharged back into the
+cistern by a specially constructed discharge pipe, so devised that
+the liquor, which is sent into it with great force by the pump, is
+diverted so as to pour straight down in order to prevent any eddies
+which could cause the cloth to wander from its course. The cloth is
+supported to and from the cylinders by flat perforated plates in
+such a manner that the force of the liquor cannot bag or displace
+the threads of the cloth, and by this means also the liquor has a
+further tendency to penetrate the fibers of the cloth. Means are
+provided for readily and expeditiously cleansing the entire
+machine. The next machine which we have to notice in this exhibit
+is Farmer's patent marking and measuring machine, the purpose of
+which is to stamp on the cloths the lengths of the same at regular
+distances. It is very desirable that drapers should have some
+simple means of discovering at a glance what amount of material
+they have in stock without the necessity of unrolling their cloth
+to measure it, and this machine seems to perfectly meet the demands
+of the case. The arrangement for effecting the printing and inking
+is shown in our engraving at A. It is contained within a small
+disk, which can be moved at will, so that it can be adapted to
+various widths of cloth or other material. A measuring roller runs
+beside the printing disk, and on this is stamped the required
+figures by a simple contrivance at the desired distances, say every
+five yards. The types are linked together into a roller chain which
+is carried by the disk, A, and they ink themselves automatically
+from a flannel pad. The machine works in this way: The end of the
+piece to be measured is brought down until it touches the surface
+of the table, the marker is turned to zero, and also the finger of
+the dial on the end of the measuring roller. The machine is then
+started, and the lengths are printed at the required distances
+until it becomes necessary to cut out the first piecing or joint in
+the fabric. The dial registers the total length of the piece.</p>
+
+<hr>
+<p><a name="6"></a></p>
+
+<h2>ENDLESS ROPE HAULAGE.</h2>
+
+<p>In the North of England Report, the endless rope systems are
+classified as No. 1 and No 2 systems. No. 1, which has the rope
+under the tubs, is said to be in operation in the Midland counties.
+To give motion to the rope a single wheel is used, and friction for
+driving the rope is supplied either by clip pulleys or by taking
+the rope over several wheels. The diagram shows an arrangement for
+a tightening arrangement. One driving wheel is used, says <i>The
+Colliery Guardian</i>, and the rope is kept constantly tight by
+passing it round a pulley fixed upon a tram to which a heavy weight
+is attached. Either one or two lines of rails are used. When a
+single line is adopted the rope works backward and forward, only
+one part being on the wagon way and the other running by the side
+of the way. When two lines are used the ropes move always in one
+direction, the full tubs coming out on one line and the empties
+going in on the other. The rope passes under the tubs, and the
+connection is made by means of a clamp or by sockets in the rope,
+to which the set is attached by a short chain. The rope runs at a
+moderately high speed.</p>
+
+<p class="ctr"><a href="./illustrations/3b.png"><img src=
+"./illustrations/3b_th.jpg" alt=
+" TIGHTENING ARRANGEMENT&mdash;ENDLESS ROPE HAULAGE."></a></p>
+
+<p class="ctr">TIGHTENING ARRANGEMENT&mdash;ENDLESS ROPE
+HAULAGE.</p>
+
+<p>No. 2 system was peculiar to Wigan. A double line of rails is
+always used. The rope rests upon the tubs, which are attached to
+the rope either singly or in sets varying in number from two to
+twelve. The other engraving shows a mode of connection between the
+tubs and the rope by a rope loop as shown.</p>
+
+<p class="ctr"><a href="./illustrations/3c.png"><img src=
+"./illustrations/3c_th.jpg" alt=
+" ATTACHMENT TO ENDLESS ROPE &quot;OVER.&quot;"></a></p>
+
+<p class="ctr">ATTACHMENT TO ENDLESS ROPE "OVER."</p>
+
+<p>The tubs are placed at a regular distance apart, and the rope
+works slowly. Motion is given to the rope by large driving pulleys,
+and friction is obtained by taking the rope several times round the
+driving pulley.</p>
+
+<hr>
+<p><a name="7"></a></p>
+
+<h2>A RELIABLE WATER FILTER.</h2>
+
+<p>Opinions are so firmly fixed at present that water is capable of
+carrying the germs of disease that, in cases of epidemics, the
+recommendation is made to drink natural mineral waters, or to boil
+ordinary water. This is a wise measure, assuredly; but mineral
+waters are expensive, and, moreover, many persons cannot get used
+to them. As for boiled water, that is a beverage which has no
+longer a normal composition; a portion of its salts has become
+precipitated, and its dissolved gases have been given off. In spite
+of the aeration that it is afterward made to undergo, it preserves
+an insipid taste, and I believe that it is not very digestible. I
+have thought, then, that it would be important, from a hygienic
+standpoint, to have a filter that should effectually rid water of
+all the microbes or germs that it contains, while at the same time
+preserving the salts or gases that it holds in solution. I have
+reached such a result, and, although it is always delicate to speak
+of things that one has himself done, I think the question is too
+important to allow me to hold back my opinion in regard to the
+apparatus. It is a question of general hygiene before which my own
+personality must disappear completely.</p>
+
+<p>In Mr. Pasteur's laboratory, we filter the liquids in which
+microbes have been cultivated, so as to separate them from the
+medium in which they exist. For this purpose we employ a small
+unglazed porcelain tube that we have had especially constructed
+therefor. The liquid traverses the porous sides of this under the
+influence of atmospheric pressure, since we cause a vacuum around
+the tube by means of an air-pump. We collect in this way, after
+several hours, a few cubic inches of a liquid which is absolutely
+pure, since animals may be inoculated with it without danger to
+them, while the smallest quantity of the same liquid, when not
+filtered, infallibly causes death.</p>
+
+<p>This is the process that I have applied to the filtration of
+water. I have introduced into it merely such modifications as are
+necessary to render the apparatus entirely practical. My apparatus
+consists of an unglazed porcelain tube inverted upon a ring of
+enameled porcelain, forming a part thereof, and provided with an
+aperture for the outflow of the liquid. This tube is placed within
+a metallic one, which is directly attached to a cock that is
+soldered to the service pipe. A nut at the base that can be
+maneuvered by hand permits, through the intermedium of a rubber
+washer resting upon the enameled ring, of the tube being
+hermetically closed.</p>
+
+<p>Under these circumstances, when the cock is turned on, the water
+fills the space between the two tubes and slowly filters, under the
+influence of pressure, through the sides of the porous one, and is
+freed from all solid matter, including the microbes and germs, that
+it contains. It flows out thoroughly purified, through the lower
+aperture, into a vessel placed there to receive it.</p>
+
+<p>I have directly ascertained that water thus filtered is deprived
+of all its germs. For this purpose I have added some of it (with
+the necessary precautions against introducing foreign organisms) to
+very changeable liquids, such as veal broth, blood, and milk, and
+have found that there was no alteration. Such water, then, is
+incapable of transmitting the germs of disease.</p>
+
+<p class="ctr"><a href="./illustrations/4a.png"><img src=
+"./illustrations/4a_th.jpg" alt=" CHAMBERLAND'S WATER FILTER.">
+</a></p>
+
+<p class="ctr">CHAMBERLAND'S WATER FILTER.</p>
+
+<p>With an apparatus like the one here figured, and in which the
+filtering tube is eight inches in length by about one inch in
+diameter, about four and a half gallons of water per day may be
+obtained when the pressure is two atmospheres&mdash;the mean
+pressure in Mr. Pasteur's laboratory, where my experiments were
+made. Naturally, the discharge is greater or less according to the
+pressure. A discharge of three and a half to four and a half
+gallons of water seems to me to be sufficient for the needs of an
+ordinary household. For schools, hospitals, barracks, etc., it is
+easy to obtain the necessary volume of water by associating the
+tubes in series. The discharge will be multiplied by the number of
+tubes.</p>
+
+<p>In the country, or in towns that have no water mains, it will be
+easy to devise an arrangement for giving the necessary pressure. An
+increase in the porosity of the filtering tube is not to be thought
+of, as this would allow very small germs to pass. This filter being
+a perfect one, we must expect to see it soil quickly. Filters that
+do not get foul are just the ones that do not filter. But with the
+arrangement that I have adopted the solid matters deposit upon the
+external surface of the filter, while the inner surface always
+remains perfectly clean. In order to clean the tube, it is only
+necessary to take it out and wash it vigorously. As the tube is
+entirely of porcelain, it may likewise be plunged into boiling
+water so as to destroy the germs that may have entered the sides
+or, better yet, it may be heated over a gas burner or in an
+ordinary oven. In this way all the organic matter will be burned,
+and the tube will resume its former porosity.&mdash;<i>M.
+Chamberland, La Nature.</i></p>
+
+<hr>
+<p><a name="8"></a></p>
+
+<h2>SIMPLE DEVICES FOR DISTILLING WATER.</h2>
+
+<p>The alchemists dreamed and talked of that universal solvent
+which they so long and vainly endeavored to discover; still, for
+all this, not only the alchemist of old, but his more immediate
+successor, the chemist of to-day, has found no solvent so universal
+as water. No liquid has nearly so wide a range of dissolving
+powers, and, taking things all round, no liquid exercises so slight
+an action upon the bodies dissolved&mdash;evaporate the water away,
+and the dissolved substance is obtained in an unchanged condition;
+at any rate, this is the general rule.</p>
+
+<p>The function of water in nature is essentially that of a solvent
+or a medium of circulation; it is not, in any sense, a food, yet
+without it no food can be assimilated by an animal. Without water
+the solid materials of the globe would be unable to come together
+so closely as to interchange their elements; and unless the
+temperatures were sufficiently high to establish an igneous
+fluidity, such as undoubtedly exists in the sun, there would be no
+circulation of matter to speak of, and the earth would be, as it
+were, locked up or dead.</p>
+
+<p>When we look upon water as the nearest approach to a universal
+solvent that even the astute scientist of to-day has been able to
+discover, who can wonder that it is never found absolutely pure in
+nature? For wherever it accumulates it dissolves something from its
+surroundings. Still, in a rain-drop just formed we have very nearly
+pure water; but even this contains dissolved air to the extent of
+about one-fiftieth of its volume, and as the drop falls downward it
+takes up such impurities as may be floating in the atmosphere; so
+that if our rain-drop is falling immediately after a long drought,
+it becomes charged with nitrate or nitrite of ammonia and various
+organic matters&mdash;perhaps also the spores or germs of disease.
+Thus it will be seen that rain tends to wonderfully clear or wash
+the atmosphere, and we all know how much a first rain is
+appreciated as an air purifier, and how it carries down with it
+valuable food for plants. The rain-water, in percolating through or
+over the land, flows mainly toward the rivers, and in doing so it
+becomes more or less charged with mineral matter, lime salts and
+common salt being the chief of them; while some of that water which
+has penetrated more deeply into the earth takes up far more solid
+matter than is ordinarily found in river water. The bulk of this
+more or less impure water tends toward the ocean, taking with it
+its load of salt and lime. Constant evaporation, of course, takes
+place from the surface of the sea, so that the salt and lime
+accumulate, this latter being, however, ultimately deposited as
+shells, coral, and chalk, while nearly pure or naturally distilled
+water once more condenses in the form of clouds. This process, by
+which a constant supply of purified water is kept up in the natural
+economy, is imitated on a small scale when water is converted into
+steam by the action of heat, and this vapor is cooled so as to
+reproduce liquid water, the operation in question being known as
+distillation.</p>
+
+<p>For this purpose an apparatus known as a still is required; and
+although by law one must pay an annual license fee for the right to
+use a still, it is not usual for the government authorities to
+enforce the law when a still is merely used for purifying
+water.</p>
+
+<p>One of the best forms of still for the photographer to employ
+consists of a tin can or bottle in which the water is boiled, and
+to this a tin tube is adapted by means of a cork, one end of this
+tin tube terminating in a coil passing through a tub or other
+vessel of cold water. A gas burner, as shown, is a convenient
+source of heat, and in order to insure a complete condensation of
+the vapor, the water in the cooling tub must be changed now and
+again.</p>
+
+<p class="ctr"><a href="./illustrations/4b.png"><img src=
+"./illustrations/4b_th.jpg" alt=""></a></p>
+
+<p>Sometimes the vapor is condensed by being allowed to play
+against the inside of a conical cover which is adapted to a
+saucepan, and is kept cool by the external application of cold
+water; and in this case the still takes the form represented by the
+subjoined diagrams; such compact and portable stills being largely
+employed in Ireland for the private manufacture of whisky.</p>
+
+<p class="ctr"><a href="./illustrations/4c.png"><img src=
+"./illustrations/4c_th.jpg" alt=""></a></p>
+
+<p>It is scarcely necessary to say that the condensed water
+trickles down on the inside of the cone, and flows out at the
+spout.</p>
+
+<p>An extemporized arrangement of a similar character may be made
+by passing a tobacco pipe through the side of a tin saucepan as
+shown below, and inverting the lid of the saucepan; if the lid is
+now kept cool by frequent changes of water inside it, and the pipe
+is properly adjusted so as to catch the drippings from the convex
+side of the lid, a considerable quantity of distilled water may be
+collected in an hour or so.</p>
+
+<p>The proportion of solid impurities present in water as
+ordinarily met with is extremely variable: rain water which has
+been collected toward the end of a storm contains only a minute
+fraction of a grain per gallon, while river or spring water may
+contain from less than thirty grains per gallon or so and upward.
+Ordinary sea water generally contains from three to four per cent.
+of saline matter, but that of the Dead Sea contains nearly
+one-fourth of its weight of salts.</p>
+
+<p class="ctr"><a href="./illustrations/4d.png"><img src=
+"./illustrations/4d_th.jpg" alt=""></a></p>
+
+<p>The three impurities of water which most interest the
+photographer are lime or magnesia salts, which give the so-called
+hardness; chlorides (as, for example, chloride of sodium or common
+salt), which throw down silver salts; and organic matter, which may
+overturn the balance of photographic operations by causing
+premature reduction of the sensitive silver compounds. To test for
+them is easy. Hardness is easily recognizable by washing one's
+hands in the water, the soap being curdled; but in many cases one
+must rather seek for a hard water than avoid it, as the tendency of
+gelatine plates to frill is far less in hard water than in soft
+water. It is, indeed, a common and useful practice to harden the
+water used for washing by adding half an ounce or an ounce of Epsom
+salts (sulphate of magnesia) to each bucket of water.
+Chlorides&mdash;chloride of sodium or common salt being that
+usually met with&mdash;may be detected by adding a drop or two of
+nitrate of silver to half a wineglassful of the water, a few drops
+of nitric acid being then added. A slight cloudiness indicates a
+trace of chlorides, and a decided milkiness shows the presence of a
+larger quantity. If it is wished to get a somewhat more definite
+idea of the amount, it is easy to make up a series of standards for
+comparison, by dissolving known weights of common salt in distilled
+or rain water, and testing samples of them side by side with the
+water to be examined.</p>
+
+<p>Organic matters may be detected by adding a little nitrate of
+silver to the water, filtering off from any precipitate of chloride
+of silver, and exposing the clear liquid to sunlight; a clean
+stoppered bottle being the most convenient vessel to use. The
+extent to which a blackening takes place may be regarded as
+approximately proportionate to the amount of organic matter
+present.</p>
+
+<p>Filtration on a small scale is not altogether a satisfactory
+mode of purifying water, as organic impurities often accumulate in
+the filter, and enter into active putrefaction when hot weather
+sets in.&mdash;<i>Photo. News.</i></p>
+
+<hr>
+<p><a name="9"></a></p>
+
+<h2>IMPROVED FIRE-DAMP DETECTER.</h2>
+
+<p>According to the London <i>Mining Journal</i>, Mr. W.E.
+Garforth, of Normanton, has introduced an ingenious invention, the
+object of which is to detect fire-damp in collieries with the least
+possible degree of risk to those engaged in the work. Mr.
+Garforth's invention, which is illustrated in the diagram given
+below, consists in the use of a small India rubber hand ball,
+without a valve of any description; but by the ordinary action of
+compressing the ball, and then allowing it to expand, a sample of
+the suspected atmosphere is drawn from the roof, or any part of the
+mine, without the great risk which now attends the operation of
+testing for gas should the gauze of the lamp be defective. The
+sample thus obtained is then forced through a small protected tube
+on to the flame, when if gas is present it is shown by the
+well-known blue cap and elongated flame. From this description, and
+from the fact that the ball is so small that it can be carried in
+the coat pocket, or, if necessary, in the waistcoat pocket, it will
+be apparent what a valuable adjunct Mr. Garforth's invention will
+prove to the safety-lamp. It has been supposed by some persons that
+explosions have been caused by the fire-trier himself, but owing to
+his own death in most cases the cause has remained undiscovered.
+This danger will now be altogether avoided. It is well known that
+the favorite form of lamp with the firemen is the Davy, because it
+shows more readily the presence of small quantities of gas; but the
+Davy was some years ago condemned, and is now strictly prohibited
+in all Belgian and many English mines. Recent experience, gained by
+repeated experiments with costly apparatus, has resulted in not
+only proving the Davy and some other descriptions of lamps to be
+unsafe, but some of our Government Inspectors and our most
+experienced mining engineers go so far as to say that "no lamp in a
+strong current of explosive gas is safe unless protected by a tin
+shield."</p>
+
+<p class="ctr"><a href="./illustrations/4e.png"><img src=
+"./illustrations/4e_th.jpg" alt=""></a></p>
+
+<p>If such is the case, Mr. Garforth seems to have struck the
+key-note when, in the recent paper read before the Midland
+Institute of Mining and Civil Engineers, and which we have now
+before us, he says: "It would seem from the foregoing remarks that
+in any existing safety-lamp where one qualification is increased
+another is proportionately reduced; so it is doubtful whether all
+the necessary requirements of sensitiveness, resistance to strong
+currents, satisfactory light, self-extinction, perfect combustion,
+etc., can ever be combined in one lamp."</p>
+
+<p>The nearest approach to Mr. Garforth's invention which we have
+ever heard of is that of a workman at a colliery in the north of
+England, who, more than twenty years ago, to avoid the trouble of
+getting to the highest part of the roof, used a kind of air pump,
+seven or eight feet long, to extract the gas from the breaks; and
+some five years ago Mr. Jones, of Ebbw Vale, had a similar idea. It
+appears that these appliances were so cumbersome, besides requiring
+too great length or height for most mines, and necessitating the
+use of both hands, that they did not come into general use. The
+ideas, however, are totally different, and the causes which have
+most likely led to the invention of the ball and protected tube
+were probably never thought of until recently; indeed, Mr. Garforth
+writes that he has only learned about them since his paper was read
+before the Midland Institute, and some weeks after his patent was
+taken out.</p>
+
+<p>No one, says Mr. Garforth, in his paper read before the Midland
+Institute, will, I presume, deny that the Davy is more sensitive
+than the tin shield lamp, inasmuch as in the former the surrounding
+atmosphere or explosive mixture has only one thickness of gauze to
+pass through, and that on a level with the flame; while the latter
+has a number of small holes and two or three thicknesses of gauze
+(according to the construction of the lamp), which the gas must
+penetrate before it reaches the flame. Moreover, the tin shield
+lamp, when inclined to one side, is extinguished (though not so
+easily as the Mueseler); and as the inlet holes are 6 inches from
+the top, it does not show a thin stratum of fire-damp near the roof
+as perceptibly as the Davy, which admits of being put in almost a
+horizontal position. Although the Davy lamp was, nearly fifty years
+ago, pronounced unsafe, by reason of its inability to resist an
+ordinary velocity of eight feet per second, yet it is still kept in
+use on account of its sensitiveness. Its advocates maintain that a
+mine can be kept safer by using the Davy, which detects small
+quantities of gas, and thereby shows the real state of the mine,
+than by a lamp which, though able to resist a greater velocity, is
+not so sensitive, and consequently is apt to deceive. Assuming the
+Davy lamp to be condemned (as it has already been in Belgium and in
+some English mines), the Stephenson and some of the more recently
+invented lamps pronounced unsafe, then if greater shielding is
+recommended the question is, what means have we for detecting small
+quantities of fire-damp?</p>
+
+<p>It would seem from the foregoing remarks that in any existing
+safety-lamp, where one qualification is increased another is
+proportionately reduced; so it is doubtful whether all the
+necessary requirements of sensitiveness, resistance to strong
+currents, satisfactory light, self-extinction, perfect combustion,
+etc., can ever be combined in one lamp. The object of the present
+paper is to show that with the assistance of the fire-damp
+detecter, the tin shield, or any other description of lamp, is made
+as sensitive as the Davy, while its other advantages of resisting
+velocity, etc., are not in any way interfered with. As a proof of
+this I may mention that a deputy of experience recently visited a
+working place to make his inspection. He reported the stall to be
+free from gas, but when the manager and steward visited it with the
+detecter, which they applied to the roof (where it would have been
+difficult to put even a small Davy), it drew a sample of the
+atmosphere which, on being put to the test tube in the tin-shield
+lamp, at once showed the presence of fire-damp. Out of twenty-eight
+tests in a mine working a long-wall face the Davy showed gas only
+eleven times, while the detecter showed it in every case. The
+detecter, as will be perceived from the one exhibited, and the
+accompanying sectional drawing, consists simply of an oval-shaped
+India rubber ball, fitted with a mouthpiece. The diameter is about
+2&frac14; inches by 3 inches, its weight is two ounces, and it is
+so small that it can be carried without any inconvenience in the
+coat or even in the waistcoat pocket. Its capacity is such that all
+the air within it may be expelled by the compression of one
+hand.</p>
+
+<p>The mouthpiece is made to fit a tube in the bottom of the lamp,
+and when pressed against the India rubber ring on the ball-flange,
+a perfectly tight joint is made, which prevents the admission of
+any external air. The tube in the bottom of the lamp is carried
+within a short distance of the height of the wick-holder. It is
+covered at the upper end with gauze, besides being fitted with
+other thicknesses of gauze at certain distances within the tube;
+and if it be found desirable to further protect the flame against
+strong currents of air, a small valve may be placed at the inlet,
+as shown in the drawing. This valve is made of sufficient weight to
+resist the force of a strong current, and is only lifted from its
+seat by the pressure of the hand on the mouthpiece. It will be
+apparent from the small size and elasticity of the detecter that
+the test can easily be made with one hand, and when the ball is
+allowed to expand a vacuum is formed within it, and a sample of the
+atmosphere drawn from the breaks, cavities, or highest parts of the
+roof, or, of course, any portion of the mine. When the sample is
+forced through the tube near the flame, gas if present at once
+reveals itself by the elongation of the flame in the usual way, at
+the same time giving an additional proof by burning with a blue
+flame on the top of the test tube. If gas is not present, the
+distinction is easily seen by the flame keeping the same size, but
+burning with somewhat greater brightness, owing to the increased
+quality of oxygen forced upon it.</p>
+
+<p>I venture to claim for this method of detecting fire-damp among
+other advantages: 1. The detecter, on account of its size, can be
+placed in a break in the roof where an ordinary lamp&mdash;even a
+small Davy&mdash;could not be put, and a purer sample of the
+suspected atmosphere is obtained than would be the case even a few
+inches below the level of the roof, 2. The obtaining and testing of
+a sample in the manner above described takes away the possibility
+of an explosion, which might be the result if a lamp with a
+defective gauze were placed in an explosive atmosphere. No one
+knows how many explosions have not been caused by the fire-trier
+himself. This will now be avoided. (Although lamps fitted with a
+tin shield will be subjected to the same strict examination as
+hitherto, still they do not admit of the same frequent inspection
+as those without shields, for in the latter case each workman can
+examine his own lamp as an extra precaution; whereas the
+examination of the tin shield lamps will rest entirely with the
+lamp man.) 3. The lamp can be kept in a pure atmosphere while the
+sample is obtained by the detecter, and at a greater height than
+the flame in a safety-lamp could be properly distinguished. The
+test can afterward be made in a safe place, at some distance from
+the explosive atmosphere; and, owing to the vacuum formed, the ball
+(without closing the mouthpiece) has been carried a mile or more
+without the gas escaping. 4. The detecter supplies a better
+knowledge of the condition of the working places, especially in
+breaks and cavities in the roof; which latter, with the help of a
+nozzle and staff, may be reached to a height of ten feet or more,
+by the detecter being pressed against the roof and sides, or by the
+use of a special form of detecter. 5. Being able at will to force
+the contents of the detecter on to the flame, the effects of an
+explosion inside the lamp need not be feared. (This danger being
+removed, admits, I think, of the glass cylinder being made of a
+larger diameter, whereby a better light is obtained; it may also be
+considered quite as strong, when used with the detecter, as a lamp
+with a small diameter, when the latter is placed in an explosive
+atmosphere.) 6. The use of the detecter will permit the further
+protection of the present tin shield lamp, by an extra thickness of
+gauze, if such addition is found advantageous in resisting an
+increased velocity. 7. In the Mueseler, Stephenson, and other
+lamps, where the flame is surrounded by glass, there is no means of
+using the wire for shot firing. The detecter tube, although
+protected by two thicknesses of gauze, admits of this being done by
+the use of a special form of valve turned by the mouthpiece of the
+detecter. The system of firing shots or using open lamps in the
+same pit where safety lamps are used is exceedingly objectionable;
+still, under certain conditions shots may be fired without danger.
+Whether safety lamps or candles are used, it is thought the use of
+the detecter will afford such a ready means of testing that more
+examinations will be made before firing a shot, thereby insuring
+greater safety. 8. In testing for gas with a safety lamp there is a
+fear of the light being extinguished, when the lamp is suddenly
+placed in a quantity of gas, or in endeavoring to get a very small
+light; this is especially the case with some kinds of lamps. With
+the detecter this is avoided, as a large flame can be used, which
+is considered by some a preferable means of testing for small
+quantities; and the test can be made without risk. Where gas is
+present in large quantities, the blue flame at the end of the test
+tube will be found a further proof. This latter result is produced
+by the slightest compression of the ball. (I need not point out the
+inconvenience and loss of time in having to travel a mile or more
+to relight.) As regards the use of the detecter with open lights,
+several of the foregoing advantages or modifications of them will
+apply. Instead of having to use the safety lamp as at present, it
+is thought that the working place will be more frequently examined,
+for a sample of the suspected atmosphere can be carried to a safe
+place and forced on to the naked light, when, if gas be present, it
+simply burns at the end of the mouthpiece like an ordinary gas jet.
+There are other advantages, such as examining the return airways
+without exposing the lamp, etc., which will be apparent, and become
+of more or less importance according to the conditions under which
+the tests are made.</p>
+
+<p>In conclusion, I wish to paint out that the practice adopted at
+some collieries, of having all the men supplied with the most
+approved lamp (such as the Mueseler or tin shield lamp) is not a
+safe one. If the strength of a chain is only equal to the weakest
+link, it may be argued that the safety of a mine is only equal to
+that of the most careless man or most unsafe lamp in it. If,
+therefore, the deputies, whose duty it is to look for gas and
+travel the most dangerous parts of the mine, are obliged to use the
+Davy on account of its sensitiveness, may it not be said that, as
+their lamps are exposed equally with the workmen's to the high
+velocities of air, they are the weak links in the safety of the
+mine? For the reasons given, I venture to submit that the
+difficulties and dangers I have mentioned will be largely reduced,
+if not wholly overcome, by the use of the fire-damp detecter.</p>
+
+<hr>
+<p><a name="10"></a></p>
+
+<h2>CAMERA ATTACHMENT FOR PAPER PHOTO NEGATIVES.</h2>
+
+<p>In computing the weight of the various items for a photographic
+tour, the glass almost invariably comes out at the head of the
+list, and the farther or longer the journey, so much more does the
+weight of the plates stand out pre-eminent; indeed, if one goes out
+on a trip with only three dozen half-plates, the glass will
+probably weigh nearly as much as camera, backs, and tripod, in
+spite of the stipulation with the maker to supply plates on "thin
+glass."</p>
+
+<p>Next in importance to glass as a support comes paper, and it is
+quite easy to understand that the tourist in out of the way parts
+might be able to take an apparatus containing a roll of sensitive
+paper, when it would be altogether impracticable for him to take an
+equivalent surface of coated glass, and in such a case the roller
+slide becomes of especial value.</p>
+
+<p>The roller slide of Melhuish is tolerably well known, and is, we
+believe, now obtainable as an article of commerce. The slide is
+fitted up with two rollers, <i>a a</i>, and the sensitive sheets,
+<i>b b</i>, are gummed together, making one long band, the ends of
+which are gummed to pieces of paper always kept on the rollers. The
+sensitive sheets are wound off the left or reserve roller on to the
+right or exposed roller, until all are exposed.</p>
+
+<p class="ctr"><a href="./illustrations/5a.png"><img src=
+"./illustrations/5a_th.jpg" alt=""></a></p>
+
+<p>The rollers are supported on springs, <i>a&sup1; a&sup1;</i>, to
+render their motion equal; they are turned by the milled heads,
+<i>m m</i>, and clamped when each fresh sheet is brought into
+position by the nuts, <i>a&sup2; a&sup2;</i>. <i>c</i>, is a board
+which is pressed forward by springs, <i>c&sup1; c&sup1;</i>, so as
+to hold the sheet to be exposed, and keep it smooth against the
+plate of glass, <i>d</i>; when the sheet has been exposed, the
+board is drawn back from the glass in order to release the exposed
+sheet, and allow it to be rolled on the exposed roller; the board
+is kept back while this is being done by turning the square rod,
+<i>c&sup2;</i>, half round, so that the angles of the square will
+not pass back through the square opening until again turned
+opposite to it; <i>e e</i> are doors, by opening which the operator
+can see (through the yellow glass, <i>y y</i>) to adjust the
+position of the sensitive sheets when changing them.</p>
+
+<p>The remarkable similarity of such a slide to the automatic
+printing-frame described last week will strike the reader; and,
+like the printing-frame, it possesses the advantage of speed in
+working&mdash;no small consideration to the photographer in a
+distant, and possibly hostile, country.</p>
+
+<p>Fine paper well sized with an insoluble size and coated with a
+sensitive emulsion is, we believe, the very best material to use in
+the roller slide; and such a paper might be made in long lengths at
+a very low price, a coating machine similar to that constructed for
+use in making carbon tissue being employed. We have used such paper
+with success, and hope that some manufacturer will introduce it
+into commerce before long. But the question suggests itself, how
+are the paper negatives to be rendered transparent, and how is the
+grain of the paper to be obliterated? Simply by pressure, as
+extremely heavy rolling will render such paper almost as
+transparent as glass, a fact abundantly demonstrated by Mr.
+Woodbury in his experiments on the Photo-Filigrane process, and
+confirmed by some trials which we have made.</p>
+
+<p>It must be confessed that roller slide experiments which we have
+made with sensitive films supported on gelatine sheets, or on such
+composite sheets as the alternate rubber and collodion pellicle of
+Mr. Warnerke, have been hardly satisfactory&mdash;possibly,
+however, from our own want of skill; while no form of the Calotype
+process which we have tried has proved so satisfactory as
+gelatino-bromide paper.&mdash;<i>Photo. News</i>.</p>
+
+<hr>
+<p><a name="11"></a></p>
+
+<h2>INSTANTANEOUS PHOTO SHUTTER.</h2>
+
+<p>M. Audra, in the name of M. Braun, of Angoul&ecirc;me, has
+presented to the Photo Society of France a new instantaneous
+shutter. The shutter is formed by a revolving metallic disk out of
+which a segment has been taken. This disk is placed in the center
+of the diaphragms, in order to obtain the greatest rapidity
+combined with the least possible distance to travel. On the axis to
+which this circular disk is fixed is a small wheel, to which is
+attached a piece of string, and when the disk is turned round for
+the exposure the string is wound round the wheel. If the string be
+pulled, naturally the disk will revolve back to its former position
+so much the more quickly the more violently the string is pulled.
+M. Braun has replaced the hand by a steel spring attached to the
+drum of the lens (Fig. 2) By shortening or lengthening the string,
+more or less rapid exposures may be obtained.</p>
+
+<p class="ctr"><a href="./illustrations/5b.png"><img src=
+"./illustrations/5b_th.jpg" alt=
+" AAA, lens; B, aperture of lens; C, metallic disk; D,"></a></p>
+
+<p class="ctr">AAA, lens; B, aperture of lens; C, metallic disk; D,
+wheel on the axis; E, cord or string; E&sup1;E&sup1;E&sup1;E&sup1;,
+knots in string; G, steel spring; H, catch; K, socket for
+catch.</p>
+
+<hr>
+<p><a name="12"></a></p>
+
+<h2>SULPHUROUS ACID.&mdash;EASY METHOD OF PREPARATION FOR
+PHOTOGRAPHIC PURPOSES.</h2>
+
+<p>Within a short period sulphurous acid has become an important
+element in the preparation of an excellent pyro developer for
+gelatine plates; and as it is more or less unstable in its keeping
+qualities, some easy method of preparing a small quantity which
+shall have a uniform strength is desirable. A method recently
+described in the <i>Photographic News</i> will afford the amateur
+photographer a ready way of preparing a small quantity of the
+acid.</p>
+
+<p class="ctr"><a href="./illustrations/5c.png"><img src=
+"./illustrations/5c_th.jpg" alt=""></a></p>
+
+<p>In the illustration given above, A and B are two bottles, both
+of which can be closed tightly with corks. A hole is made in the
+cork in the bottle, A, a little smaller than the glass tube which
+connects A and B. It is filed out with a rat-tail file until it is
+large enough to admit the tube very tightly. The tube may be bent
+easily, by being heated over a common fish-tail gas burner or over
+the top of the chimney of a kerosene lamp, so as to form two right
+angles, one end extending close to the bottom of the bottle B as
+shown.</p>
+
+<p>Having fitted up the apparatus, about two ounces of hyposulphite
+of soda are placed in the bottle A, while the bottle B is about
+three-fourths filled with water&mdash;distilled or melted ice water
+is to be preferred; some sulphuric acid&mdash;about two
+ounces&mdash;is now diluted with about twice its bulk of water, by
+first putting the water into a dish and pouring in the acid in a
+steady stream, stirring meanwhile. It is well to set the dish in a
+sink, to avoid any damage which might occur through the breaking of
+the dish by the heat produced; when cool, the solution is ready for
+use and may be kept in a bottle.</p>
+
+<p>The cork which serves to adapt the bent tube to the bottle A is
+now just removed for an instant, the other end remaining in the
+water in bottle B, and about two or three ounces of the dilute acid
+are poured in upon the hyposulphite, after which the cork is
+immediately replaced.</p>
+
+<p>Sulphurous acid is now evolved by the action of the acid on the
+hypo, and as the gas is generated it is led as a series of bubbles
+through the water in the bottle B as shown. The air space above the
+water in bottle B soon becomes filled by displacement with
+sulphurous acid gas, which is a little over twice as heavy as air;
+so in order to expedite the complete saturation of the water, it is
+convenient to remove the bottle A with its tube from bottle B, and
+after having closed the latter by its cork or stopper, to agitate
+it thoroughly by turning the bottle upside down. As the sulphurous
+acid gas accumulated in the air space over the water is absorbed by
+the water, a partial vacuum is created, and when the stopper is
+eased an inrush of air may be noted. When, after passing fresh gas
+through the liquid for some minutes, no further inrush of air is
+noted on easing the stopper as before described after agitating the
+bottle, it may be concluded that the water is thoroughly saturated
+with sulphurous acid and is strong enough for immediate use. More
+gas can be generated by adding more dilute sulphuric acid to the
+hypo until the latter is decomposed; then it should be thrown
+aside, and a fresh charge put in the bottle. On preparing the
+solution it is well to set the bottles on the outside ledge of the
+window, or in some other open situation where no inconvenience will
+result from the escape of the excess of sulphurous gas as it
+bubbles through the water.</p>
+
+<p>The solution of sulphurous acid, if preserved at all, ought to
+be kept in small bottles, completely filled and perfectly closed;
+but as it is very easy to saturate a considerable quantity of water
+with sulphurous acid gas in a short time, there is but little
+inducement to use a solution which may possibly have become
+weakened by keeping.</p>
+
+<p>Care should be taken not to add too much dilute acid to the hypo
+at a time, else excessive effervescence will occur, and the
+solution will froth over the top of the bottle.</p>
+
+<hr>
+<p><a name="16"></a></p>
+
+<h2>THE NATIONAL MONUMENT AT ROME.</h2>
+
+<p>About three years ago the Italian Government invited the
+architects and artists of the world to furnish competitive designs
+for a national monument to be erected to the memory of King Victor
+Emanuel II. at Rome. More than $1,800,000 were appropriated for the
+monument exclusive of the foundation. It is very seldom that an
+artist has occasion to carry out as grand and interesting a work as
+this was to be: the representation of the creator of the Italian
+union in the new capitol of the new state surrounded by the ruins
+and mementos of a proud and mighty past. Prizes of $10,000, $6,000,
+and $4,000 were donated for the first, second, and third prize
+designs respectively. Designs were entered, not only from Italy,
+but also from Germany, France, Norway, Sweden, England, and
+America, and even from Caucasus and Japan.</p>
+
+<p class="ctr"><a href="./illustrations/6a.png"><img src=
+"./illustrations/6a_th.jpg" alt=
+" THE UNION OF ITALY. SACCONI'S PRIZE DESIGN FOR THE"></a></p>
+
+<p class="ctr">THE UNION OF ITALY. SACCONI'S PRIZE DESIGN FOR THE
+NATIONAL MONUMENT, ROME, ITALY.</p>
+
+<p>The height and size of the monument were not determined on, nor
+was the exact location, and the competitors had full liberty in
+relation to the artistic character of the monument, and it was left
+for them to decide whether it should be a triumphal arch, a column,
+a temple, a mausoleum, or any other elaborate design. This great
+liberty given to the competitors was of great value and service to
+the monument commission, as it enabled them to decide readily what
+the character of the monument should be but it was a dangerous
+point for the artists, at which most of them foundered. The
+competition was resultless. Two prizes were given, but new designs
+had to be called for, which were governed more or less by a certain
+programme issued by the committee.</p>
+
+<p>In place of the Piazza de Termini, a square extending from the
+church of St. Maria degli Angeli to the new Via Nazionale, to which
+preference was given by the competitors, the heights of Aracoeli
+were chosen. The monument was to be erected at this historic place
+in front of the side wall of the church, with the center toward the
+Corso, high above the surrounding buildings. The programme called
+for an equestrian statue of the King located in front of an
+architectural background which was to cover the old church walls,
+and was to be reached by a grand staircase.</p>
+
+<p>Even the result of this second competition was not definite, but
+as the designers were guided by the programme, the results obtained
+were much more satisfactory. The commission decided not to award
+the first prize, but honored the Italian architects Giuseppi
+Sacconi and Manfredo Manfredi, and the German Bruno Schmitz, with a
+prize of $2,000 each; and requested them to enter into another
+competition and deliver their models within four months, so as to
+enable the commission to come to a final decision. On June 18, the
+commission decided to accept Sacconi's design for execution, and
+awarded a second prize of $2,000 to Manfredi.</p>
+
+<p>Sacconi's design, shown opposite page, cut taken from the
+<i>Illustrirte Zeitung</i>, needs but little explanation. An
+elegant gallery of sixteen Corinthian columns on a high, prominent
+base is crowned by a high attica and flanked by pavilions. It forms
+the architectural background for the equestrian statue, and is
+reached by an elaborately ornamented staircase.</p>
+
+<p>Manfredi's design shows a handsomely decorated wall in place of
+the gallery, and in front of the wall an amphitheater is arranged,
+in the center of which the equestrian statue is placed. Bruno
+Schmitz' design shows a rich mosaic base supporting an Ionic
+portico, from the middle of which a six column Corinthian "pronaos"
+projects, which no doubt would have produced a magnificent effect
+in the streets of Rome.</p>
+
+<hr>
+<p><a name="17"></a></p>
+
+<h2>ON THE EVOLUTION OF FORMS OF ORNAMENT. <a name=
+"FNanchor_2"></a><a href="#Footnote_2"><sup>1</sup></a></h2>
+
+<p>The statement that modern culture can be understood only through
+a study of all its stages of development is equally true of its
+several branches.</p>
+
+<p>Let us assume that decorative art is one of these. It contains
+in itself, like language and writing, elements of ancient and even
+of prehistoric forms, but it must, like these other expressions of
+culture, which are forever undergoing changes, adapt itself to the
+new demands which are made upon it, not excepting the very
+arbitrary ones of fashion; and it is owing to this cause that,
+sometimes even in the early stages of its development, little or
+nothing of its original form is recognizable. Investigations the
+object of which is to clear up this process of development as far
+as possible are likely to be of some service; a person is more
+likely to recognize the beauties in the details of ornamental works
+of art if he has an acquaintance with the leading styles, and the
+artist who is freed from the bondage of absolute tradition will be
+put into a better position to discriminate between accidental and
+arbitrary and organic and legitimate forms, and will thus have his
+work in the creation of new ones made more easy for him.</p>
+
+<p>Hence I venture to claim some measure of indulgence in
+communicating the results of the following somewhat theoretical
+investigations, as they are not altogether without a practical
+importance. I must ask the reader to follow me into a modern
+drawing-room, not into one that will dazzle us with its cold
+elegance, but into one whose comfort invites us to remain in
+it.</p>
+
+<p>The simple stucco ceiling presents a central rosette, which
+passes over by light conventional floral forms into the general
+pattern of the ceiling. The frieze also, which is made of the same
+material, presents a similar but somewhat more compact floral
+pattern as its chief motive. Neither of these, though they belong
+to an old and never extinct species, has as yet attained the
+dignity of a special name.</p>
+
+<p>The walls are covered with a paper the ornamentation of which is
+based upon the designs of the splendid textile fabrics of the
+middle ages, and represents a floral pattern of spirals and
+climbing plants, and bears evident traces of the influence of
+Eastern culture. It is called a pomegranate or pine-apple pattern,
+although in this case neither pomegranates nor pine-apples are
+recognizable.</p>
+
+<p>Similarly with respect to the pattern of the coverings of the
+chairs and sofas and of the stove-tiles; these, however, show the
+influence of Eastern culture more distinctly.</p>
+
+<p>The carpet also, which is not a true Oriental one, fails to
+rivet the attention, but gives a quiet satisfaction to the eye,
+which, as it were, casually glances over it, by its simple pattern,
+which is derived from Persian-Indian archetypes (Cashmere pattern,
+Indian palmettas), and which is ever rhythmically repeating itself
+(see Fig. 1).</p>
+
+<p class="ctr"><a href="./illustrations/7a.png"><img src=
+"./illustrations/7a_th.jpg" alt=" FIG. 1."></a></p>
+
+<p class="ctr">FIG. 1.</p>
+
+<p>The floral pattern on the dressing-gown of the master of the
+house, as well as on the light woolen shawl that is thrown round
+the shoulders of his wife, and even the brightly colored glass
+knicknacks on the mantel-piece, manufactured in Silesia after the
+Indian patterns of the Reuleaux collection, again show the same
+motive; in the one case in the more geometrical linear arrangement,
+in the other in the more freely entwined spirals.</p>
+
+<p>Now you will perhaps permit me to denominate these three groups
+of patterns that occur in our new home fabrics as modern patterns.
+Whether we shall in the next season be able, in the widest sense of
+the word, to call these patterns modern naturally depends on the
+ruling fashion of the day, which of course cannot be calculated
+upon (Fig. 2).</p>
+
+<p class="ctr"><a href="./illustrations/7b.png"><img src=
+"./illustrations/7b_th.jpg" alt=" FIG. 2."></a></p>
+
+<p class="ctr">FIG. 2.</p>
+
+<p>I beg to be allowed to postpone the nearer definition of the
+forms that occur in the three groups, which, however, on a closer
+examination all present a good deal that they have in common.
+Taking them in a general way, they all show a leaf-form inclosing
+an inflorescence in the form of an ear or thistle; or at other
+times a fruit or a fruit-form. In the same way with the stucco
+ornaments and the wall-paper pattern.</p>
+
+<p>The Cashmere pattern also essentially consists of a leaf with
+its apex laterally expanded; it closes an ear-shaped flower-stem,
+set with small florets, which in exceptional cases protrude beyond
+the outline of the leaf; the whole is treated rigorously as an
+absolute flat ornament, and hence its recognition is rendered
+somewhat more difficult. The blank expansion of the leaf is not
+quite unrelieved by ornament, but is set off with small points,
+spots, and blossoms. This will be thought less strange if we
+reflect on the Eastern representations of animals, in the portrayal
+of which the flat expanses produced by the muscle-layers are often
+treated from a purely decorative point of view, which strikes us as
+an exaggeration of convention.</p>
+
+<p class="ctr"><a href="./illustrations/7c.png"><img src=
+"./illustrations/7c_th.jpg" alt=" FIG. 3."></a></p>
+
+<p class="ctr">FIG. 3.</p>
+
+<p>One cannot go wrong in taking for granted that plant-forms were
+the archetypes of all these patterns. Now we know that it holds
+good, as a general principle in the history of civilization, that
+the tiller of the ground supplants the shepherd, as the shepherd
+supplants the hunter; and the like holds also in the history of the
+branch of art we are discussing&mdash;representations of animals
+are the first to make their appearance, and they are at this period
+remarkable for a wonderful sharpness of characterization. At a
+later stage man first begins to exhibit a preference for
+plant-forms as subjects for representation, and above all for such
+as can in any way be useful or hurtful to him. We, however, meet
+such plant-forms used in ornament in the oldest extant monuments of
+art in Egypt, side by side with representations of animals; but the
+previous history of this very developed culture is unknown. In such
+cases as afford us an opportunity of studying more primitive though
+not equally ancient stages of culture, as for instance among the
+Greeks, we find the above dictum confirmed, at any rate in cases
+where we have to deal with the representation of the indigenous
+flora as contradistinguished from such representations of plants as
+were imported from foreign civilizations. In the case that is now
+to occupy us, we have not to go back so very far in the history of
+the world.</p>
+
+<p class="ctr"><a href="./illustrations/7d.png"><img src=
+"./illustrations/7d_th.jpg" alt=" FIG. 4."></a></p>
+
+<p class="ctr">FIG. 4.</p>
+
+<p>The ornamental representations of plants are of two kinds. Where
+we have to deal with a simple pictorial reproduction of plants as
+symbols (laurel branches, boughs of olive and fir, and branches of
+ivy), <i>i. e</i>., with a mere characteristic decoration of a
+technical structure, stress is laid upon the most faithful
+reproduction of the object possible&mdash;the artist is again and
+again referred to the study of Nature in order to imitate her.
+Hence, as a general rule, there is less difficulty in the
+explanation of these forms, because even the minute details of the
+natural object now and then offer points that one can fasten upon.
+It is quite another thing when we have to deal with actual
+decoration which does not aim at anything further than at employing
+the structural laws of organisms in order to organize the unwieldy
+substance, to endow the stone with a higher vitality. These latter
+forms depart, even at the time when they originate, very
+considerably from the natural objects. The successors of the
+originators soon still further modify them by adapting them to
+particular purposes, combining and fusing them with other forms so
+as to produce particular individual forms which have each their own
+history (<i>e.g</i>., the acanthus ornament, which, in its
+developed form, differs very greatly from the acanthus plant
+itself); and in a wider sense we may here enumerate all such forms
+as have been raised by art to the dignity of perfectly viable
+beings, <i>e.g</i>., griffins, sphinxes, dragons, and angels.</p>
+
+<p class="ctr"><a href="./illustrations/7e.png"><img src=
+"./illustrations/7e_th.jpg" alt=" Fig. 5."></a></p>
+
+<p class="ctr">Fig. 5.</p>
+
+<p>The deciphering and derivation of such forms as these is
+naturally enough more difficult; in the case of most of them we are
+not even in possession of the most necessary preliminaries to the
+investigation, and in the case of others there are very important
+links missing (<i>e.g</i>., for the well-known Greek palmettas). In
+proportion as the representation of the plant was a secondary
+object, the travesty has been more and more complete. As in the
+case of language, where the root is hardly recognizable in the
+later word, so in decorative art the original form is
+indistinguishable in the ornament. The migration of races and the
+early commercial intercourse between distant lands have done much
+to bring about the fusion of types; but again in contrast to this
+we find, in the case of extensive tracts of country, notably in the
+Asiatic continent, a fixity, throughout centuries, of forms that
+have once been introduced, which occasions a confusion between
+ancient and modern works of art, and renders investigations much
+more difficult. An old French traveler writes: "J'ai vu dans le
+tr&eacute;sor d'Ispahan les vetements de Tamerlan; ils ne different
+en rien de ceux d'aujourd'hui." Ethnology, the natural sciences,
+and last, but not least, the history of technical art are here set
+face to face with great problems.</p>
+
+<p class="ctr"><a href="./illustrations/7f.png"><img src=
+"./illustrations/7f_th.jpg" alt=" FIG. 6."></a></p>
+
+<p class="ctr">FIG. 6.</p>
+
+<p>In the case in point, the study of the first group of artistic
+forms that have been elaborated by Western art leads to definite
+results, because the execution of the forms in stone can be
+followed on monuments that are relatively not very old, that are
+dated, and of which the remains are still extant. In order to
+follow the development, I ask your permission to go back at once to
+the very oldest of the known forms. They come down to us from the
+golden era of Greek decorative art&mdash;from the fourth or fifth
+century B.C.&mdash;when the older simple styles of architecture
+were supplanted by styles characterized by a greater richness of
+structure and more developed ornament. A number of flowers from
+capitals in Priene, Miletus, Eleusis, Athens (monument of
+Lysicrates), and Pergamon; also flowers from the calathos of a
+Greek caryatid in the Villa Albani near Rome, upon many Greek
+sepulchral wreaths, upon the magnificent gold helmet of a Grecian
+warrior (in the Museum of St. Petersburg)&mdash;these show us the
+simplest type of the pattern in question, a folded leaf, that has
+been bulged out, inclosing a knob or a little blossom (see Figs. 3
+and 4). This is an example from the Temple of Apollo at Miletus,
+one that was constructed about ten years ago, for educational
+purposes. Here is the specimen of the flower of the monument to
+Lysicrates at Athens, of which the central part consists of a small
+flower or fruits (Figs. 5 and 6).</p>
+
+<p class="ctr"><a href="./illustrations/7g.png"><img src=
+"./illustrations/7g_th.jpg" alt=" FIG. 7."></a></p>
+
+<p class="ctr">FIG. 7.</p>
+
+<p>The form passes over into Roman art. The larger scale of the
+buildings, and the pretensions to a greater richness in details,
+lead to a further splitting up of the leaf into acanthus-like
+forms. Instead of a fruit-form a fir-cone appears, or a pine-apple
+or other fruit in an almost naturalistic form.</p>
+
+<p>In a still larger scale we have the club-shaped knob developing
+into a plant-stem branching off something after the fashion of a
+candelabrum, and the lower part of the leaf, where it is folded
+together in a somewhat bell-shaped fashion, becomes in the true
+sense of the word a campanulum, out of which an absolute
+vessel-shaped form, as <i>e.g</i>. is to be seen in the frieze of
+the Basilica Ulpia in Rome, becomes developed.</p>
+
+<p class="ctr"><a href="./illustrations/7h.png"><img src=
+"./illustrations/7h_th.jpg" alt=" FIG. 8."></a></p>
+
+<p class="ctr">FIG. 8.</p>
+
+<p>Such remains of pictorial representation as are still extant
+present us with an equally perfect series of developments. The
+splendid Gr&aelig;co-Italian vessels, the richly ornamented Apulian
+vases, show flowers in the spirals of the ornaments, and even in
+the foreground of the pictorial representations, which correspond
+exactly to the above mentioned Greek relief representations. [The
+lecturer sent round, among other illustrations, a small photograph
+of a celebrated vase in Naples (representing the funeral rites of
+Patroclus), in which the flower in question appears in the
+foreground, and is perhaps also employed as ornament.] (Figs. 7 and
+8.)</p>
+
+<p>The Pompeian paintings and mosaics, and the Roman paintings, of
+which unfortunately very few specimens have come down to us, show
+that the further developments of this form were most manifold, and
+indeed they form in conjunction with the Roman achievements in
+plastic art the highest point that this form reached in its
+development, a point that the Renaissance, which followed hard upon
+it, did not get beyond.</p>
+
+<p class="ctr"><a href="./illustrations/8a.png"><img src=
+"./illustrations/8a_th.jpg" alt=" FIG. 9."></a></p>
+
+<p class="ctr">FIG. 9.</p>
+
+<p>Thus the work of Raphael from the loggias follows in unbroken
+succession upon the forms from the Therm&aelig; of Titus. It is
+only afterward that a freer handling of the traditional pattern
+arose, characterized by the substitution of, for instance, maple or
+whitethorn for the acanthus-like forms. Often even the central part
+falls away completely, or is replaced by overlapping leaves. In the
+forms of this century we have the same process repeated. Schinkel
+and Botticher began with the Greek form, and have put it to various
+uses; Stuler, Strack, Gropius, and others followed in their wake
+until the more close resemblance to the forms of the period of the
+Renaissance in regard to Roman art which characterizes the present
+day was attained (Fig. 9).</p>
+
+<p>Now, what plant suggested this almost indispensable form of
+ornament, which ranks along with the acanthus and palmetta, and
+which has also become so important by a certain fusion with the
+structural laws of both?</p>
+
+<p class="ctr"><a href="./illustrations/8b.png"><img src=
+"./illustrations/8b_th.jpg" alt=" FIG. 10."></a></p>
+
+<p class="ctr">FIG. 10.</p>
+
+<p>We meet with organism of the form in the family of the
+Arace&aelig;, or aroid plants. An enveloping leaf (bract), called
+the spathe, which is often brilliantly colored, surrounds the
+florets, or fruits, that are disposed upon a spadix. Even the older
+writers&mdash;Theophrastus, Dioscorides, Galen, and
+Pliny&mdash;devote a considerable amount of attention to several
+species of this interesting family, especially to the value of
+their swollen stems as a food-stuff, to their uses in medicine,
+etc. Some species of Arum were eaten, and even nowadays the value
+of the swollen stems of some species of the family causes them to
+be cultivated, as, for instance, in Egypt and India, etc. (the
+so-called Portland sago, Portland Island arrowroot, is prepared
+from the swollen stems of <i>Arum maculatum</i>). In contrast with
+the smooth or softly undulating outlines of the spathe of
+Mediterranean Arace&aelig;, one species stands out in relief, in
+which the sharply-marked fold of the spathe almost corresponds to
+the forms of the ornaments which we are discussing. It is
+<i>Dracunculus vulgaris</i>, and derives its name from its stem,
+which is spotted like a snake. This plant, which is pretty widely
+distributed in olive woods and in the river valleys of the
+countries bordering on the Mediterranean, was employed to a
+considerable extent in medicine by the ancients (and is so still
+nowadays, according to Von Heldreich, in Greece). It was, besides,
+the object of particular regard, because it was said not only to
+heal snake-bite, but the mere fact of having it about one was
+supposed to keep away snakes, who were said altogether to avoid the
+places where it grew. But, apart from this, the striking appearance
+of this plant, which often grows to an enormous size, would be
+sufficient to suggest its employment in art. According to
+measurements of Dr. Julius Schmidt, who is not long since dead, and
+was the director of the Observatory at Athens, a number of these
+plants grow in the Valley of Cephisus, and attain a height of as
+much as two meters, the spathe alone measuring nearly one meter.
+[The lecturer here exhibited a drawing (natural size) of this
+species, drawn to the measurements above referred to.]</p>
+
+<p class="ctr"><a href="./illustrations/8c.png"><img src=
+"./illustrations/8c_th.jpg" alt=" FIG. 11."></a></p>
+
+<p class="ctr">FIG. 11.</p>
+
+<p>Dr. Sintenis, the botanist, who last year traveled through Asia
+Minor and Greece, tells me that he saw beautiful specimens of the
+plant in many places, <i>e.g</i>., in Assos, in the neighborhood of
+the Dardanelles, under the cypresses of the Turkish cemeteries.</p>
+
+<p>The inflorescence corresponds almost exactly to the ornament,
+but the multipartite leaf has also had a particular influence upon
+its development and upon that of several collateral forms which I
+cannot now discuss. The shape of the leaf accounts for several as
+yet unexplained extraordinary forms in the ancient plane-ornament,
+and in the Renaissance forms that have been thence developed. It
+first suggested the idea to me of studying the plant attentively
+after having had the opportunity five years ago of seeing the
+leaves in the Botanic Gardens at Pisa. It was only afterward that I
+succeeded in growing some flowers which fully confirmed the
+expectations that I had of them (Figs. 10 and 11).</p>
+
+<p class="ctr"><a href="./illustrations/8d.png"><img src=
+"./illustrations/8d_th.jpg" alt=" FIG. 12."></a></p>
+
+<p class="ctr">FIG. 12.</p>
+
+<p>The leaf in dracunculus has a very peculiar shape; it consists
+of a number of lobes which are disposed upon a stalk which is more
+or less forked (tends more or less to dichotomize). If you call to
+your minds some of the Pompeian wall decorations, you will perceive
+that similar forms occur there in all possible variations. Stems
+are regularly seen in decorations that run perpendicularly,
+surrounded by leaves of this description. Before this, these
+suggested the idea of a misunderstood (or very conventional)
+perspective representation of a circular flower. Now the form also
+occurs in this fashion, and thus negatives the idea of a
+perspective representation of a closed flower. It is out of this
+form in combination with the flower-form that the series of
+patterns was developed which we have become acquainted with in
+Roman art, especially in the ornament of Titus' Therm&aelig; and in
+the Renaissance period in Raphael's work. [The lecturer here
+explained a series of illustrations of the ornaments referred to
+(Figs. 12, 13, 14).]</p>
+
+<p>The attempt to determine the course of the first group of forms
+has been to a certain extent successful, but we meet greater
+difficulties in the study of the second.</p>
+
+<p class="ctr"><a href="./illustrations/8e.png"><img src=
+"./illustrations/8e_th.jpg" alt=" FIG. 13."></a></p>
+
+<p class="ctr">FIG. 13.</p>
+
+<p>It is difficult to obtain a firm basis on which to conduct our
+investigations from the historical or geographical point of view
+into this form of art, which was introduced into the West by
+Arabico-Moorish culture, and which has since been further developed
+here. There is only one method open to us in the determination of
+the form, which is to pass gradually from the richly developed and
+strongly differentiated forms to the smaller and simpler ones, even
+if these latter should have appeared contemporaneously or even
+later than the former. Here we have again to refer to the fact that
+has already been mentioned, to wit, that Oriental art remained
+stationary throughout long periods of time. In point of fact, the
+simpler forms are invariably characterized by a nearer and nearer
+approach to the more ancient patterns and also to the natural
+flower-forms of the Arace&aelig;. We find the spathe, again,
+sometimes drawn like an acanthus leaf, more often, however, bulged
+out, coming to be more and more of a mere outline figure, and
+becoming converted into a sort of background; then the spadix,
+generally conical in shape, sometimes, however, altogether replaced
+by a perfect thistle, at other times again by a pomegranate.
+Auberville, in his magnificent work "L'Ornement des Tissus," is
+astonished to find the term pomegranate-pattern almost confined to
+these forms, since their central part is generally formed of a
+thistle-form. As far as I can discover in the literature that is at
+my disposal, this question has not had any particular attention
+devoted to it except in the large work upon Ottoman architecture
+published in Constantinople under the patronage of Edhem Pasha. The
+pomegranate that has served as the original of the pattern in
+question is in this work surrounded with leaves till it gives some
+sort of an approach to the pattern. (There are important
+suggestions in the book as to the employment of melon-forms.)
+Whoever has picked the fruit from the tender twigs of the
+pomegranate tree, which are close set with small altered leaves,
+will never dream of attributing the derivation of the thorny leaves
+that appear in the pattern to pomegranate leaves at any stage of
+their development.</p>
+
+<p class="ctr"><a href="./illustrations/8f.png"><img src=
+"./illustrations/8f_th.jpg" alt=" FIG. 14"></a></p>
+
+<p class="ctr">FIG. 14</p>
+
+<p>It does not require much penetration to see that the outline of
+the whole form corresponds to the spathe of the Arace&aelig;, even
+although in later times the jagged contour is all that has remained
+of it, and it appears to have been provided with ornamental forms
+quite independently of the rest of the pattern. The inner
+thistle-form cannot be derived from the common thistle, because the
+surrounding leaves negative any such idea. The artichoke theory
+also has not enough in its favor, although the artichoke, as well
+as the thistle, was probably at a later time directly pressed into
+service. Prof. Ascherson first called my attention to the extremely
+anciently cultivated plant, the safflor (<i>Carthamus
+tinctoris</i>, Fig. 15), a thistle plant whose flowers were
+employed by the ancients as a dye. Some drawings and dried
+specimens, as well as the literature of the subject, first gave me
+a hope to find that this plant was the archetype of this ornament,
+a hope that was borne out by the study of the actual plant,
+although I was unable to grow it to any great perfection.</p>
+
+<p>In the days of the Egyptian King Sargo (according to Ascherson
+and Schweinfurth) this plant was already well known as a plant of
+cultivation; in a wild state it is not known (De Candolle,
+"Originel des Plantes cultiv&eacute;es"). In Asia its cultivation
+stretches to Japan. Semper cites a passage from an Indian drama to
+the effect that over the doorway there was stretched an arch of
+ivory, and about it were bannerets on which wild safran
+(<i>Saflor</i>) was painted.</p>
+
+<p class="ctr"><a href="./illustrations/8g.png"><img src=
+"./illustrations/8g_th.jpg" alt=" FIG. 15"></a></p>
+
+<p class="ctr">FIG. 15</p>
+
+<p>The importance of the plant as a dye began steadily to decrease,
+and it has now ceased to have any value as such in the face of the
+introduction of newer coloring matters (a question that was treated
+of in a paper read a short time ago by Dr. Reimann before this
+Society). Perhaps its only use nowadays is in the preparation of
+rouge (<i>rouge v&eacute;g&eacute;tale</i>).</p>
+
+<p>But at a time when dyeing, spinning, and weaving were, if not in
+the one hand, yet at any rate intimately connected with one another
+in the narrow circle of a home industry, the appearance of this
+beautiful gold-yellow plant, heaped up in large masses, would be
+very likely to suggest its immortalization in textile art, because
+the drawing is very faithful to nature in regard to the thorny
+involucre. Drawings from nature of the plant in the old botanical
+works of the sixteenth and seventeenth centuries look very like
+ornamental patterns. Now after the general form had been
+introduced, pomegranates or other fruits&mdash;for instance,
+pine-apples&mdash;were introduced within the nest of leaves.</p>
+
+<p class="ctr"><a href="./illustrations/8h.png"><img src=
+"./illustrations/8h_th.jpg" alt=" FIG. 16."></a></p>
+
+<p class="ctr">FIG. 16.</p>
+
+<p>Into the detailed study of the intricacies of this subject I
+cannot here enter; the East-Asian influences are not to be
+neglected, which had probably even in early times an effect upon
+the form that was assumed, and have fused the correct style of
+compound flowers for flat ornament with the above-mentioned forms,
+so as to produce peculiar patterns; we meet them often in the
+so-called Persian textures and flat ornaments (Fig. 16).</p>
+
+<p>We now come to the third group of forms&mdash;the so-called
+Cashmere pattern, or Indian palmetta. The developed forms, which,
+when they have attained their highest development, often show us
+outlines that are merely fanciful, and represent quite a bouquet of
+flowers leaning over to one side, and springing from a vessel (the
+whole corresponding to the Roman form with the vessel), must be
+thrown to one side, while we follow up the simpler forms, because
+in this case also we have no information as to either the where or
+the when the forms originated. (Figs. 17, 18, 19.)</p>
+
+<p class="ctr"><a href="./illustrations/8i.png"><img src=
+"./illustrations/8i_th.jpg" alt=" FIG. 17."></a></p>
+
+<p class="ctr">FIG. 17.</p>
+
+<p>Here again we are struck by resemblances to the forms that were
+the subjects of our previous study, we even come across direct
+transitional forms, which differ from the others only by the
+lateral curve of the apex of the leaf; sometimes it is the central
+part, the spadix, that is bent outward, and the very details show a
+striking agreement with the structure of the aroid inflorescence,
+so much so that one might regard them as actually copied from
+them.</p>
+
+<p class="ctr"><a href="./illustrations/8j.png"><img src=
+"./illustrations/8j_th.jpg" alt=" FIG. 18."></a></p>
+
+<p class="ctr">FIG. 18.</p>
+
+<p>This form of ornament has been introduced into Europe since the
+French expedition to Egypt, owing to the importation of genuine
+Cashmere shawls. (When it cropped up in isolated forms, as in
+Venice in the fifteenth century, it appears not to have exerted any
+influence; its introduction is perhaps rather to be attributed to
+calico-printing.) Soon afterward the European shawl-manufacture,
+which is still in a flourishing state, was introduced. Falcot
+informs us that designs of a celebrated French artist, Couder, for
+shawl-patterns, a subject that he studied in India itself, were
+exported back to that country and used there (Fig. 20).</p>
+
+<p>In these shawl-patterns the original simple form meets us in a
+highly developed, magnificent, and splendidly colored
+differentiation and elaboration. This we can have no scruples in
+ranking along with the medi&aelig;val plane-patterns, which we have
+referred to above, among the highest achievements of decorative
+art.</p>
+
+<p class="ctr"><a href="./illustrations/8k.png"><img src=
+"./illustrations/8k_th.jpg" alt=" FIG. 19."></a></p>
+
+<p class="ctr">FIG. 19.</p>
+
+<p>It is evident that it, at any rate in this high stage of
+development, resisted fusion with Western forms of art. It is all
+the more incumbent upon us to investigate the laws of its
+existence, in order to make it less alien to us, or perhaps to
+assimilate it to ourselves by attaining to an understanding of
+those laws. A great step has been made when criticism has, by a
+more painstaking study, put itself into a position to characterize
+as worthless ignorantly imitated, or even original, miscreations
+such as are eternally cropping up. If we look at our modern
+manufactures immediately after studying patterns which enchant us
+with their classical repose, or after it such others as captivate
+the eye by their beautiful coloring, or the elaborative working out
+of their details, we recognize that the beautifully balanced form
+is often cut up, choked over with others, or mangled (the flower
+springing up side down from the leaves), the whole being traversed
+at random by spirals, which are utterly foreign to the spirit of
+such a style, and all this at the caprice of uncultured, boorish
+designers. Once we see that the original of the form was a plant,
+we shall ever in the developed, artistic form cling, in a general
+way at least, to the laws of its organization, and we shall at any
+rate be in a position to avoid violent incongruities.</p>
+
+<p class="ctr"><a href="./illustrations/8l.png"><img src=
+"./illustrations/8l_th.jpg" alt=" FIG. 20."></a></p>
+
+<p class="ctr">FIG. 20.</p>
+
+<p>I had resort, a few years ago, to the young botanist Ruhmer,
+assistant at the Botanical Museum at Sch&ouml;neberg, who has
+unfortunately since died of some chest-disease, in order to get
+some sort of a groundwork for direct investigations. I asked him to
+look up the literature of the subject, with respect to the
+employment of the Indian Arace&aelig; for domestic uses or in
+medicine. A detailed work on the subject was produced, and
+establishes that, quite irrespective of species of Alocasia and
+Colocasia that have been referred to, a large number of
+Arace&aelig; were employed for all sorts of domestic purposes.
+Scindapsus, which was used as a medicine, has actually retained a
+Sanskrit name, "vustiva." I cannot here go further into the details
+of this investigation, but must remark that even the incomplete and
+imperfect drawings of these plants, which, owing to the difficulty
+of preserving them, are so difficult to collect through travelers,
+exhibit such a wealth of shape, that it is quite natural that
+Indian and Persian flower-loving artists should be quite taken with
+them, and employ them enthusiastically in decorative art. Let me
+also mention that Haeckel, in his '"Letters of an Indian Traveler,"
+very often bears witness to the effect of the Arace&aelig; upon the
+general appearance of the vegetation, both in the full and enormous
+development of species of Caladia and in the species of Pothos
+which form such impenetrable mazes of interlooping stems.</p>
+
+<p>In conclusion, allow me to remark that the results of my
+investigation, of which but a succinct account has been given here,
+negative certain derivations, which have been believed in, though
+they have never been proved; such as that of the form I have last
+discussed from the Assyrian palmetta, or from a cypress bent down
+by the wind. To say the least the laws of formation here laid down
+have a more intimate connection with the forms as they have come
+down to us, and give us a better handle for future use and
+development. The object of the investigation was, in general words,
+to prepare for an explanation of the questions raised; and even if
+the results had turned out other than they have, it would have
+sufficed me to have given an impulse to labors which will testify
+to the truth of the dead master's words:</p>
+
+<pre>
+    "Was Du ererbt von deinen V&auml;tern hast,
+    Erwirb es, um es zu besitzen."
+</pre>
+
+<a name="Footnote_2"></a><a href="#FNanchor_2">[1]</a>
+
+<div class="note">From a paper by Prof. Jacobsthal in the
+<i>Transactions</i> of the Arch&aelig;ological Society of
+Berlin.&mdash;<i>Nature</i></div>
+
+<hr>
+<p><a name="13"></a></p>
+
+<h2>STEPS TOWARD A KINETIC THEORY OF MATTER.<a name=
+"FNanchor_3"></a><a href="#Footnote_3"><sup>1</sup></a></h2>
+
+<h3>By Sir WILLIAM THOMSON.</h3>
+
+<p>The now well known kinetic theory of gases is a step so
+important in the way of explaining seemingly static properties of
+matter by motion, that it is scarcely possible to help anticipating
+in idea the arrival at a complete theory of matter, in which all
+its properties will be seen to be merely attributes of motion. If
+we are to look for the origin of this idea we must go back to
+Democritus, Epicurus, and Lucretius. We may then, I believe,
+without missing a single step, skip 1800 years. Early last century
+we find in Malebranche's "Recherche de la Verite," the statement
+that "la durete de corps" depends on "petits tourbillons."<a name=
+"FNanchor_4"></a><a href="#Footnote_4"><sup>2</sup></a> These
+words, embedded in a hopeless mass of unintelligible statements of
+the physical, metaphysical, and theological philosophies of the
+day, and unsupported by any explanation, elucidation, or
+illustration throughout the rest of the three volumes, and only
+marred by any other single sentence or word to be found in the
+great book, still do express a distinct conception which forms a
+most remarkable step toward the kinetic theory of matter. A little
+later we have Daniel Bernoulli's promulgation of what we now accept
+as a surest article of scientific faith&mdash;the kinetic theory of
+gases. He, so far as I know, thought only of Boyle's and Mariotte's
+law of the "spring of air," as Boyle called it, without reference
+to change of temperature or the augmentation of its pressure if not
+allowed to expand for elevation of temperature, a phenomenon which
+perhaps he scarcely knew, still less the elevation of temperature
+produced by compression, and the lowering of temperature by
+dilatation, and the consequent necessity of waiting for a fraction
+of a second or a few seconds of time (with apparatus of ordinary
+experimental magnitude), to see a subsidence from a larger change
+of pressure down to the amount of change that verifies Boyle's law.
+The consideration of these phenomena forty years ago by Joule, in
+connection with Bernoulli's original conception, formed the
+foundation of the kinetic theory of gases as we now have it. But
+what a splendid and useful building has been placed on this
+foundation by Clausius and Maxwell, and what a beautiful ornament
+we see on the top of it in the radiometer of Crookes, securely
+attached to it by the happy discovery of Tait and Dewar,<a name=
+"FNanchor_5"></a><a href="#Footnote_5"><sup>3</sup></a> that the
+length of the free path of the residual molecules of air in a good
+modern vacuum may amount to several inches! Clausius' and Maxwell's
+explanations of the diffusion of gases, and of thermal conduction
+in gases, their charmingly intelligible conclusion that in gases
+the diffusion of heat is just a little more rapid than the
+diffusion of molecules, because of the interchange of energy in
+collisions between molecules,<a name="FNanchor_6"></a><a href=
+"#Footnote_6"><sup>4</sup></a> while the chief transference of heat
+is by actual transport of the molecules themselves, and Maxwell's
+explanation of the viscosity of gases, with the absolute numerical
+relations which the work of those two great discoverers found among
+the three properties of diffusion, thermal conduction, and
+viscosity, have annexed to the domain of science a vast and ever
+growing province.</p>
+
+<p>Rich as it is in practical results, the kinetic theory of gases,
+as hitherto developed, stops absolutely short at the atom or
+molecule, and gives not even a suggestion toward explaining the
+properties in virtue of which the atoms or molecules mutually
+influence one another. For some guidance toward a deeper and more
+comprehensive theory of matter, we may look back with advantage to
+the end of last century and beginning of this century, and find
+Rumford's conclusion regarding the heat generated in boring a brass
+gun: "It appears to me to be extremely difficult, if not quite
+impossible, to form any distinct idea of anything capable of being
+excited and communicated in the manner the heat was excited and
+communicated in these experiments, except it be MOTION;" and Davy's
+still more suggestive statements: "The phenomena of repulsion are
+not dependent on a peculiar elastic fluid for their existence." ...
+"Heat may be defined as a peculiar motion, probably a vibration, of
+the corpuscles of bodies, tending to separate them." ... "To
+distinguish this motion from others, and to signify the causes of
+our sensations of heat, etc., the name <i>repulsive</i> motion has
+been adopted." Here we have a most important idea. It would be
+somewhat a bold figure of speech to say the earth and moon are kept
+apart by a repulsive motion; and yet, after all, what is
+centrifugal force but a repulsive motion, and may it not be that
+there is no such thing as repulsion, and that it is solely by
+inertia that what seems to be repulsion is produced? Two bodies fly
+together, and, accelerated by mutual attraction, if they do not
+precisely hit one another, they cannot but separate in virtue of
+the inertia of their masses. So, after dashing past one another in
+sharply concave curves round their common center of gravity, they
+fly asunder again. A careless onlooker might imagine they had
+repelled one another, and might not notice the difference between
+what he actually sees and what he would see if the two bodies had
+been projected with great velocity toward one another, and either
+colliding and rebounding, or repelling one another into sharply
+convex continuous curves, fly asunder again.</p>
+
+<p>Joule, Clausius, and Maxwell, and no doubt Daniel Bernoulli
+himself, and I believe every one who has hitherto written or done
+anything very explicit in the kinetic theory of gases, has taken
+the mutual action of molecules in collision as repulsive. May it
+not after all be attractive? This idea has never left my mind since
+I first read Davy's "Repulsive Motion," about thirty-five years
+ago, and I never made anything of it, at all events have not done
+so until to-day (June 16, 1884)&mdash;if this can be said to be
+making anything of it&mdash;when, in endeavoring to prepare the
+present address, I notice that Joule's and my own old experiments<a
+name="FNanchor_7"></a><a href="#Footnote_7"><sup>5</sup></a> on the
+thermal effect of gases expanding from a high-pressure vessel
+through a porous plug, proves the less dense gas to have greater
+intrinsic <i>potential</i> energy than the denser gas, if we assume
+the ordinary hypothesis regarding the temperature of a gas,
+according to which two gases are of equal temperatures<a name=
+"FNanchor_8"></a><a href="#Footnote_8"><sup>6</sup></a> when the
+kinetic energies of their constituent molecules are of equal
+average amounts per molecule.</p>
+
+<p>Think of the thing thus. Imagine a great multitude of particles
+inclosed by a boundary which may be pushed inward in any part all
+round at pleasure. Now station an engineer corps of Maxwell's army
+of sorting demons all round the inclosure, with orders to push in
+the boundary diligently everywhere, when none of the besieged
+troops are near, and to do nothing when any of them are seen
+approaching, and until after they have turned again inward. The
+result will be that, with exactly the same sum of kinetic and
+potential energies of the same inclosed multitude of particles, the
+throng has been caused to be denser. Now Joule's and my own old
+experiments on the efflux of air prove that if the crowd be common
+air, or oxygen, or nitrogen, or carbonic acid, the temperature is a
+little higher in the denser than in the rarer condition when the
+energies are the same. By the hypothesis, equality of temperature
+between two different gases or two portions of the same gas at
+different densities means equality of kinetic energies in the same
+number of molecules of the two. From our observations proving the
+temperature to be higher, it therefore follows that the potential
+energy is smaller in the condensed crowd. This&mdash;always,
+however, under protest as to the temperature
+hypothesis&mdash;proves some degree of attraction among the
+molecules, but it does not prove ultimate attraction between two
+molecules in collision, or at distances much less than the average
+mutual distance of nearest neighbors in the multitude. The
+collisional force might be repulsive, as generally supposed
+hitherto, and yet attraction might predominate in the whole
+reckoning of difference between the intrinsic potential energies of
+the more dense and less dense multitudes.</p>
+
+<p>It is however remarkable that the explanation of the propagation
+of sound through gases, and even of the positive fluid pressure of
+a gas against the sides of the containing vessel, according to the
+kinetic theory of gases, is quite independent of the question
+whether the ultimate collisional force is attractive or repulsive.
+Of course it must be understood that, if it is attractive, the
+particles must, be so small that they hardly ever meet&mdash;they
+would have to be infinitely small to <i>never</i> meet&mdash;that,
+in fact, they meet so seldom, in comparison with the number of
+times their courses&mdash;are turned through large angles by
+attraction, that the influence of these surely attractive
+collisions is preponderant over that of the comparatively very rare
+impacts from actual contact. Thus, after all, the train of
+speculation suggested by Davy's "Repulsive Motion" does not allow
+us to escape from the idea of true repulsion, does not do more than
+let us say it is of no consequence, nor even say this with truth,
+because, if there are impacts at all, the nature of the force
+during the impact and the effects of the mutual impacts, however
+rare, cannot be evaded in any attempt to realize a conception of
+the kinetic theory of gases. And in fact, unless we are satisfied
+to imagine the atoms of a gas as mathematical points endowed with
+inertia, and as, according to Boscovich, endowed with forces of
+mutual, positive, and negative attraction, varying according to
+some definite function of the distance, we cannot avoid the
+question of impacts, and of vibrations and rotations of the
+molecules resulting from impacts, and we must look distinctly on
+each molecule as being either a little elastic solid or a
+configuration of motion in a continuous all-pervading liquid. I do
+not myself see how we can ever permanently rest anywhere short of
+this last view; but it would be a very pleasant temporary
+resting-place on the way to it if we could, as it were, make a
+mechanical model of a gas out of little pieces of round, perfectly
+elastic solid matter, flying about through the space occupied by
+the gas, and colliding with one another and against the sides of
+the containing vessel.</p>
+
+<p>This is, in fact, all we have of the kinetic theory of gases up
+to the present time, and this has done for us, in the hands of
+Clausius and Maxwell, the great things which constitute our first
+step toward a molecular theory of matter. Of course from it we
+should have to go on to find an explanation of the elasticity and
+all the other properties of the molecules themselves, a subject
+vastly more complex and difficult than the gaseous properties, for
+the explanation of which we assume the elastic molecule; but
+without any explanation of the properties of the molecule itself,
+with merely the assumption that the molecule has the requisite
+properties, we might rest happy for a while in the contemplation of
+the kinetic theory of gases, and its explanation of the gaseous
+properties, which is not only stupendously important as a step
+toward a more thoroughgoing theory of matter, but is undoubtedly
+the expression of a perfectly intelligible and definite set of
+facts in Nature.</p>
+
+<p>But alas for our mechanical model consisting of the cloud of
+little elastic solids flying about among one another. Though each
+particle have absolutely perfect elasticity, the end must be pretty
+much the same as if it were but imperfectly elastic. The average
+effect of repeated and repeated mutual collisions must be to
+gradually convert all the translational energy into energy of
+shriller and shriller vibrations of the molecule. It seems certain
+that each collision must have something more of energy in
+vibrations of very finely divided nodal parts than there was of
+energy in such vibrations before the impact. The more minute this
+nodal subdivision, the less must be the tendency to give up part of
+the vibrational energy into the shape of translational energy in
+the course of a collision; and I think it is rigorously
+demonstrable that the whole translational energy must ultimately
+become transformed into vibrational energy of higher and higher
+nodal subdivisions if each molecule is a continuous elastic solid.
+Let us, then, leave the kinetic theory of gases for a time with
+this difficulty unsolved, in the hope that we or others after us
+may return to it, armed with more knowledge of the properties of
+matter, and with sharper mathematical weapons to cut through the
+barrier which at present hides from us any view of the molecule
+itself, and of the effects other than mere change of translational
+motion which it experiences in collision.</p>
+
+<p>To explain the elasticity of a gas was the primary object of the
+kinetic theory of gases. This object is only attainable by the
+assumption of an elasticity more complex in character, and more
+difficult of explanation, than the elasticity of gases&mdash;the
+elasticity of a solid. Thus, even if the fatal fault in the theory,
+to which I have alluded, did not exist, and if we could be
+perfectly satisfied with the kinetic theory of gases founded on the
+collisions of elastic solid molecules, there would still be beyond
+it a grander theory which need not be considered a chimerical
+object of scientific ambition&mdash;to explain the elasticity of
+solids. But we may be stopped when we commence to look in the
+direction of such a theory with the cynical question, What do you
+mean by explaining a property of matter? As to being stopped by any
+such question, all I can say is that if engineering were to be all
+and to end all physical science, we should perforce be content with
+merely finding properties of matter by observation, and using them
+for practical purposes. But I am sure very few, if any, engineers
+are practically satisfied with so narrow a view of their noble
+profession. They must and do patiently observe, and discover by
+observation, properties of matter and results of material
+combinations. But deeper questions are always present, and always
+fraught with interest to the true engineer, and he will be the last
+to give weight to any other objection to any attempt to see below
+the surface of things than the practical question, Is it likely to
+prove wholly futile? But now, instead of imagining the question,
+What do you mean by explaining a property of matter? to be put
+cynically, and letting ourselves be irritated by it, suppose we
+give to the questioner credit for being sympathetic, and condescend
+to try and answer his question. We find it not very easy to do so.
+All the properties of matter are so connected that we can scarcely
+imagine one <i>thoroughly explained</i> without our seeing its
+relation to all the others, without in fact having the explanation
+of all; and till we have this we cannot tell what we mean by
+"explaining a property" or "explaining the properties" of matter.
+But though this consummation may never be reached by man, the
+progress of science may be, I believe will be, step by step toward
+it, on many different roads converging toward it from all sides.
+The kinetic theory of gases is, as I have said, a true step on one
+of the roads. On the very distinct road of chemical science, St.
+Claire Deville arrived at his grand theory of dissociation without
+the slightest aid from the kinetic theory of gases. The fact that
+he worked it out solely from chemical observation and experiment,
+and expounded it to the world without any hypothesis whatever, and
+seemingly even without consciousness of the beautiful explanation
+it has in the kinetic theory of gases, secured for it immediately
+an independent solidity and importance as a chemical theory when he
+first promulgated it, to which it might even by this time scarcely
+have attained if it had first been suggested as a probability
+indicated by the kinetic theory of gases, and been only afterward
+confirmed by observation. Now, however, guided by the views which
+Clausius and Williamson have given us of the continuous interchange
+of partners between the compound molecules constituting chemical
+compounds in the gaseous state, we see in Deville's theory of
+dissociation a point of contact of the most transcendent interest
+between the chemical and physical lines of scientific progress.</p>
+
+<p>To return to elasticity: if we could make out of matter devoid
+of elasticity a combined system of relatively moving parts which,
+in virtue of motion, has the essential characteristics of an
+elastic body, this would surely be, if not positively a step in the
+kinetic theory of matter, at least a fingerpost pointing a way
+which we may hope will lead to a kinetic theory of matter. Now
+this, as I have already shown,<a name="FNanchor_9"></a><a href=
+"#Footnote_9"><sup>7</sup></a> we can do in several ways. In the
+case of the last of the communications referred to, of which only
+the title has hitherto been published, I showed that, from the
+mathematical investigation of a gyrostatically dominated
+combination contained in the passage of Thomson and Tait's "Natural
+Philosophy" referred to, it follows that any ideal system of
+material particles, acting on one another mutually through massless
+connecting springs, may be perfectly imitated in a model consisting
+of rigid links jointed together, and having rapidly rotating fly
+wheels pivoted on some or on all of the links. The imitation is not
+confined to cases of equilibrium. It holds also for vibration
+produced by disturbing the system infinitesimally from a position
+of stable equilibrium and leaving it to itself. Thus we may make a
+gyrostatic system such that it is in equilibrium under the
+influence of certain positive forces applied to different points of
+this system; all the forces being precisely the same as, and the
+points of application similarly situated to, those of the stable
+system with springs. Then, provided proper masses (that is to say,
+proper amounts and distributions of inertia) be attributed to the
+links, we may remove the external forces from each system, and the
+consequent vibration of the points of application of the forces
+will be identical. Or we may act upon the systems of material
+points and springs with any given forces for any given time, and
+leave it to itself, and do the same thing for the gyrostatic
+system; the consequent motion will be the same in the two cases. If
+in the one case the springs are made more and more stiff, and in
+the other case the angular velocities of the fly wheels are made
+greater and greater, the periods of the vibrational constituents of
+the motion will become shorter and shorter, and the amplitudes
+smaller and smaller, and the motions will approach more and more
+nearly those of two perfectly rigid groups of material points
+moving through space and rotating according to the well known mode
+of rotation of a rigid body having unequal moments of inertia about
+its three principal axes. In one case the ideal nearly rigid
+connection between the particles is produced by massless,
+exceedingly stiff springs; in the other case it is produced by the
+exceedingly rapid rotation of the fly wheels in a system which,
+when the fly wheels are deprived of their rotation, is perfectly
+limp.</p>
+
+<p>The drawings (Figs. 1 and 2) before you illustrate two such
+material systems.<a name="FNanchor_10"></a><a href=
+"#Footnote_10"><sup>8</sup></a> The directions of rotation of the
+fly-wheels in the gyrostatic system (Fig. 2) are indicated by
+directional ellipses, which show in perspective the direction of
+rotation of the fly-wheel of each gyrostat. The gyrostatic system
+(Fig. 2) might have been constituted of two gyrostatic members, but
+four are shown for symmetry. The inclosing circle represents in
+each case in section an inclosing spherical shell to prevent the
+interior from being seen. In the inside of one there are
+fly-wheels, in the inside of the other a massless spring. The
+projecting hooked rods seem as if they are connected by a spring in
+each case. If we hang any one of the systems up by the hook on one
+of its projecting rods, and hang a weight to the hook of the other
+projecting rod, the weight, when first put on, will oscillate up
+and down, and will go on doing so for ever if the system be
+absolutely unfrictional. If we check the vibration by hand, the
+weight will hang down at rest, the pin drawn out to a certain
+degree; and the distance drawn out will be simply proportional to
+the weight hung on, as in an ordinary spring balance.</p>
+
+<p class="ctr"><a href="./illustrations/10a.png"><img src=
+"./illustrations/10a_th.jpg" alt=" FIG. 1"></a></p>
+
+<p class="ctr">FIG. 1</p>
+
+<p class="ctr"><a href="./illustrations/10b.png"><img src=
+"./illustrations/10b_th.jpg" alt=" FIG. 2"></a></p>
+
+<p class="ctr">FIG. 2</p>
+
+<p>Here, then, out of matter possessing rigidity, but absolutely
+devoid of elasticity, we have made a perfect model of a spring in
+the form of a spring balance. Connect millions of millions of
+particles by pairs of rods such as these of this spring balance,
+and we have a group of particles constituting an elastic solid;
+exactly fulfilling the mathematical ideal worked out by Navier,
+Poisson, and Cauchy, and many other mathematicians, who, following
+their example, have endeavored to found a theory of the elasticity
+of solids on mutual attraction and repulsion between a group of
+material particles. All that can possibly be done by this theory,
+with its assumption of forces acting according to any assumed law
+of relation to distance, is done by the gyrostatic system. But the
+gyrostatic system does, besides, what the system of naturally
+acting material particles cannot do&mdash;it constitutes an elastic
+solid which can have the Faraday magneto-optic rotation of the
+plane of polarization of light; supposing the application of our
+solid to be a model of the luminiferous ether for illustrating the
+undulatory theory of light. The gyrostatic model spring balance is
+arranged to have zero moment of momentum as a whole, and therefore
+to contribute nothing to the Faraday rotation; with this
+arrangement the model illustrates the luminiferous ether in a field
+unaffected by magnetic force. But now let there be a different
+rotational velocity imparted to the jointed square round the axis
+of the two projecting hooked rods, such as to give a resultant
+moment of momentum round any given line through the center of
+inertia of the system; and let pairs of the hooked rods in the
+model thus altered, which is no longer a model of a mere spring
+balance, be applied as connections between millions of pairs of
+particles as before, with the lines of resultant moment of momentum
+all similarly directed. We now have a model elastic solid which
+will have the property that the direction of vibration in waves of
+rectilinear vibrations propagated through it shall turn round the
+line of propagation of the waves, just as Faraday's observation
+proves to be done by the line of vibration of light in a dense
+medium between the poles of a powerful magnet. The case of wave
+front perpendicular to the lines of resultant moment of momentum
+(that is to say, the direction of propagation being parallel to
+these lines) corresponds, in our mechanical model, to the case of
+light traveling in the direction of the lines of force in a
+magnetic field.</p>
+
+<p>In these illustrations and models we have different portions of
+ideal rigid matter acting upon one another, by normal pressure at
+mathematical points of contact&mdash;of course no forces of
+friction are supposed. It is exceedingly interesting to see how
+thus, with no other postulates than inertia, rigidity, and mutual
+impenetrability, we can thoroughly model not only an elastic solid,
+and any combination of elastic solids, but so complex and recondite
+a phenomenon as the passage of polarized light through a magnetic
+field. But now, with the view of ultimately discarding the
+postulate of rigidity from all our materials, let us suppose some
+to be absolutely destitute of rigidity, and to possess merely
+inertia and incompressibility, and mutual impenetrability with
+reference to the still remaining rigid matter. With these
+postulates we can produce a perfect model of mutual action at a
+distance between solid particles, fulfilling the condition, so
+keenly desired by Newton and Faraday, of being explained by
+continuous action through an intervening medium. The law of the
+mutual force in our model, however, is not the simple Newtonian
+law, but the much more complex law of the mutual action between
+electro magnets&mdash;with this difference, that in the
+hydro-kinetic model in every case the force is opposite in
+direction to the corresponding force in the electro-magnetic
+analogue. Imagine a solid bored through with a hole, and placed in
+our ideal perfect liquid. For a moment let the hole be stopped by a
+diaphragm, and let an impulsure pressure be applied for an instant
+uniformly over the whole membrane, and then instantly let the
+membrane be dissolved into liquid. This action originates a motion
+of the liquid relatively to the solid, of a kind to which I have
+given the name of "irrotational circulation," which remains
+absolutely constant however the solid be moved through the liquid.
+Thus, at any time the actual motion of the liquid at any point in
+the neighborhood of the solid will be the resultant of the motion
+it would have in virtue of the circulation alone, were the solid at
+rest, and the motion it would have in virtue of the motion of the
+solid itself, had there been no circulation established through the
+aperture. It is interesting and important to remark in passing that
+the whole kinetic energy of the liquid is the sum of the kinetic
+energies which it would have in the two cases separately. Now,
+imagine the whole liquid to be inclosed in an infinitely large,
+rigid, containing vessel, and in the liquid, at an infinite
+distance from any part of the containing vessel, let two perforated
+solids, with irrotational circulation through each, be placed at
+rest near one another. The resultant fluid motion due to the two
+circulations, will give rise to fluid pressure on the two bodies,
+which, if unbalanced, will cause them to move. The force
+systems&mdash;force-and-torques, or pairs of forces&mdash;required
+to prevent them from moving will be mutual and opposite, and will
+be the same as, but opposite in direction to, the mutual force
+systems required to hold at rest two electromagnets fulfilling the
+following specification: The two electro magnets are to be of the
+same shape and size as the two bodies, and to be placed in the same
+relative positions, and to consist of infinitely thin layers of
+electric currents in the surfaces of solids possessing extreme
+diamagnetic quality&mdash;in other words, infinitely small
+permeability. The distribution of electric current on each body may
+be any whatever which fulfills the condition that the total current
+across any closed line drawn on the surface once through the
+aperture is equal to &frac14; &pi; of the circulation<a name=
+"FNanchor_11"></a><a href="#Footnote_11"><sup>9</sup></a> through
+the aperture in the hydro-kinetic analogue.</p>
+
+<p>It might be imagined that the action at a distance thus provided
+for by fluid motion could serve as a foundation for a theory of the
+equilibrium, and the vibrations, of elastic solids, and the
+transmission of waves like those of light through an extended
+quasi-elastic solid medium. But unfortunately for this idea the
+equilibrium is essentially unstable, both in the case of magnets
+and, notwithstanding the fact that the forces are oppositely
+directed, in the hydro-kinetic analogue also, when the several
+movable bodies (two or any greater number) are so placed relatively
+as to be in equilibrium. If, however, we connect the perforated
+bodies with circulation through them in the hydro-kinetic system,
+by jointed rigid connecting links, we may arrange for
+configurations of stable equilibrium. Thus, without fly-wheels, but
+with fluid circulations through apertures, we may make a model
+spring balance or a model luminiferous ether, either without or
+with the rotational quality corresponding to that of the true
+luminiferous ether in the magnetic fluid&mdash;in short, do all by
+the perforated solids with circulations through them that we saw we
+could do by means of linked gyrostats. But something that we cannot
+do by linked gyrostats we can do by the perforated bodies with
+fluid circulation: we can make a model gas. The mutual action at a
+distance, repulsive or attractive according to the mutual aspect of
+the two bodies when passing within collisional distance<a name=
+"FNanchor_12"></a><a href="#Footnote_12"><sup>10</sup></a> of one
+another, suffices to produce the change of direction of motion in
+collision, which essentially constitutes the foundation of the
+kinetic theory of gases, and which, as we have seen before, may as
+well be due to attraction as to repulsion, so far as we know from
+any investigation hitherto made in this theory.</p>
+
+<p>There remains, however, as we have seen before, the difficulty
+of providing for the case of actual impacts between the solids,
+which must be done by giving them massless spring buffers or, which
+amounts to the same thing, attributing to them repulsive forces
+sufficiently powerful at very short distances to absolutely prevent
+impacts between solid and solid; unless we adopt the equally
+repugnant idea of infinitely small perforated solids, with
+infinitely great fluid circulations through them. Were it not for
+this fundamental difficulty, the hydro-kinetic model gas would be
+exceedingly interesting; and, though we could scarcely adopt it as
+conceivably a true representation of what gases really are, it
+might still have some importance as a model configuration of solid
+and liquid matter, by which without elasticity the elasticity of
+true gas might be represented.</p>
+
+<p>But lastly, since the hydro-kinetic model gas with perforated
+solids and fluid circulations through them fails because of the
+impacts between the solids, let us annul the solids and leave the
+liquid performing irrotational circulation round vacancy,<a name=
+"FNanchor_13"></a><a href="#Footnote_13"><sup>11</sup></a> in the
+place of the solid cores which we have hitherto supposed; or let us
+annul the rigidity of the solid cores of the rings, and give them
+molecular rotation according to Helmholtz's theory of vortex
+motion. For stability the molecular rotation must be such as to
+give the same velocity at the boundary of the rotational fluid core
+as that of the irrotationally circulating liquid in contact with
+it, because, as I have proved, frictional slip between two portions
+of liquid in contact is inconsistent with stability. There is a
+further condition, upon which I cannot enter into detail just now,
+but which may be understood in a general way when I say that it is
+a condition of either uniform or of increasing molecular rotation
+from the surface inward, analogous to the condition that the
+density of a liquid, resting for example under the influence of
+gravity, must either be uniform or must be greater below than above
+for stability of equilibrium. All that I have said in favor of the
+model vortex gas composed of perforated solids with fluid
+circulations through them holds without modification for the purely
+hydro-kinetic model, composed of either Helmholtz cored vortex
+rings or of coreless vortices, and we are now troubled with no such
+difficulty as that of the impacts between solids. Whether, however,
+when the vortex theory of gases is thoroughly worked out, it will
+or will not be found to fail in a manner analogous to the failure
+which I have already pointed out in connection with the kinetic
+theory of gases composed of little elastic solid molecules, I
+cannot at present undertake to speak with certainty. It seems to me
+most probable that the vortex theory cannot fail in any such way,
+because all I have been able to find out hitherto regarding the
+vibration of vortices,<a name="FNanchor_14"></a><a href=
+"#Footnote_14"><sup>12</sup></a> whether cored or coreless, does
+not seem to imply the liability of translational or impulsive
+energies of the individual vortices becoming lost in energy of
+smaller and smaller vibrations.</p>
+
+<p>As a step toward kinetic theory of matter, it is certainly most
+interesting to remark that in the quasi-elasticity, elasticity
+looking like that of an India-rubber band, which we see in a
+vibrating smoke-ring launched from an elliptic aperture, or in two
+smoke-rings which were circular, but which have become deformed
+from circularity by mutual collision, we have in reality a virtual
+elasticity in matter devoid of elasticity, and even devoid of
+rigidity, the virtual elasticity being due to motion, and generated
+by the generation of motion.</p>
+
+<a name="Footnote_3"></a><a href="#FNanchor_3">[1]</a>
+
+<div class="note">Meeting of the British Association, Montreal.
+1884. Section A. Mathematical and Physical science. Opening Address
+by Prof. Sir William Thomson, M.A., LL.D., D.C.L., F.R.SS.L. and
+E., F.R.A.S., President of the Section.</div>
+
+<a name="Footnote_4"></a><a href="#FNanchor_4">[2]</a>
+
+<div class="note">"Preuve de la supposition que j'ay faite: Que la
+matiere subtile ou etheree est necessairement composee de PETITS
+TOURBILLONS; et qu'ils sont les causes naturelles de tous les
+changements qui arrivent a la matiere; ce que je confirme par
+i'explication des effets les plus generaux de la Physique, tels que
+sont la durete des corps, leur fluidite, leur pesanteur, legerete,
+la lumiere et la refraction et reflexion de ses
+rayons."&mdash;Malebranche, "Recherche de la Verite," 1712.</div>
+
+<a name="Footnote_5"></a><a href="#FNanchor_5">[3]</a>
+
+<div class="note">Proc. R.S.E., March 2, 1874, and July 5,
+1875.</div>
+
+<a name="Footnote_6"></a><a href="#FNanchor_6">[4]</a>
+
+<div class="note">On the other hand, in liquids, on account of the
+crowdedness of the molecules, the diffusion of heat must be chiefly
+by interchange of energies between the molecules, and should be, as
+experiment proves it is, enormously more rapid than the diffusion
+of the molecules themselves, and this again ought to be much less
+rapid than either the material or thermal diffusivities of gases.
+Thus the diffusivity of common salt through water was found by Fick
+to be as small as 0.0000112 square centimeter per second; nearly
+200 times as great as this is the diffusivity of heat through
+water, which was found by J.T. Bottomley to be about 0.002 square
+centimeter per second. The material diffusivities of gases,
+according to Loschmidt's experiments, range from 0.98 (the
+interdiffusivity of carbonic acid and nitrous oxide) to 0.642 (the
+interdiffusivity of carbonic oxide and hydrogen), while the thermal
+diffusivities of gases, calculated according to Clausius' and
+Maxwell's kinetic theory of gases, are 0.089 for carbonic acid,
+0.16 for common air of other gases of nearly the same density, and
+1.12 for hydrogen (all, both material and thermal, being reckoned
+in square centimeters per second).</div>
+
+<a name="Footnote_7"></a><a href="#FNanchor_7">[5]</a>
+
+<div class="note">Republished in Sir W. Thomson's "Mathematical and
+Physical Papers," vol. i., article xlix., p. 381.</div>
+
+<a name="Footnote_8"></a><a href="#FNanchor_8">[6]</a>
+
+<div class="note">That this is a mere hypothesis has been scarcely
+remarked by the founders themselves, nor by almost any writer on
+the kinetic theory of gases. No one has yet examined the question,
+What is the condition as regards average distribution of kinetic
+energy, which is ultimately fulfilled by two portions of gaseous
+matter, separated by a thin elastic septum which absolutely
+prevents interdiffusion of matter, while it allows interchange of
+kinetic energy by collisions against itself? Indeed, I do not know
+but, that the present is the very first statement which has ever
+been published of this condition of the problem of equal
+temperatures between two gaseous masses.</div>
+
+<a name="Footnote_9"></a><a href="#FNanchor_9">[7]</a>
+
+<div class="note">Paper on "Vortex Atoms," <i>Proc</i>. R.S.E.
+February. 1867: abstract of a lecture before the Royal Institution
+of Great Britain, March 4, 1881, on "Elasticity Viewed as possibly
+a Mode of Motion"; Thomson and Tait's "Natural Philosophy," second
+edition, part 1, &sect;&sect; 345 viii. to 345 xxxvii.; "On
+Oscillation and Waves in an Adynamic Gyrostatic System" (title
+only), <i>Proc</i>. R.S.E. March, 1883.</div>
+
+<a name="Footnote_10"></a><a href="#FNanchor_10">[8]</a>
+
+<div class="note">In Fig. 1 the two hooked rods seen projecting
+from the sphere are connected by an elastic coach-spring. In Fig. 2
+the hooked rods are connected one to each of two opposite corners
+of a four-sided jointed frame, each member of which carries a
+gyrostat so that the axis of rotation of the fly-wheel is in the
+axis of the member of the frame which bears it. Each of the hooked
+rods in Fig. 2 is connected to the framework through a swivel
+joint, so that the whole gyrostatic framework may be rotated about
+the axis of the hooked rods in order to annul the moment of
+momentum of the framework about this axis due to rotation of the
+fly-wheels in the gyrostat.</div>
+
+<a name="Footnote_11"></a><a href="#FNanchor_11">[9]</a>
+
+<div class="note">The integral of tangential component velocity all
+round any closed curve, passing once through the aperture, is
+defined as the "cyclic-constant" or the "circulation" ("Vortex
+Motion," &sect; 60 (a), <i>Trans</i>. R.S.E., April 29, 1867). It
+has the same value for all closed curves passing just once through
+the aperture, and it remains constant through all time, whether the
+solid body be in motion or at rest.</div>
+
+<a name="Footnote_12"></a><a href="#FNanchor_12">[10]</a>
+
+<div class="note">According to this view, there is no precise
+distance, or definite condition respecting the distance, between
+two molecules, at which apparently they come to be in collision, or
+when receding from one another they cease to be in collision. It is
+convenient, however, in the kinetic theory of gases, to adopt
+arbitrarily a precise definition of collision, according to which
+two bodies or particles mutually acting at a distance may be said
+to be in collision when their mutual action exceeds some definite
+arbitrarily assigned limit, as, for example, when the radius of
+curvature of the path of either body is less than a stated fraction
+(one one-hundredth, for instance) of the distance between
+them.</div>
+
+<a name="Footnote_13"></a><a href="#FNanchor_13">[11]</a>
+
+<div class="note">Investigations respecting coreless vortices will
+be found in a paper by the author, "Vibrations of a Columnar
+Vortex," <i>Proc</i>. R.S.E., March 1, 1880; and a paper by Hicks,
+recently read before the Royal Society.</div>
+
+<a name="Footnote_14"></a><a href="#FNanchor_14">[12]</a>
+
+<div class="note">See papers by the author "On Vortex Motion."
+<i>Trans</i>. R.S.E. April, 1867, and "Vortex Statics,"
+<i>Proc</i>. R.S.E. December, 1875; also a paper by J.J. Thomson,
+B.A., "On the Vibrations of a Vortex Ring," <i>Trans</i>. R.S.
+December, 1881, and his valuable book on "Vortex Motion."</div>
+
+<hr>
+<p><a name="14"></a></p>
+
+<h2>APPLICATION OF ELECTRICITY TO TRAMWAYS.</h2>
+
+<h3>By M. HOLROYD SMITH.</h3>
+
+<p>Last year, when I had the pleasure of reading a paper before you
+on my new system of electric tramways, I ventured to express the
+hope that before twelve months had passed, "to be able to report
+progress," and I am happy to say that notwithstanding the wearisome
+delay and time lost in fruitless negotiations, and the hundred and
+one difficulties within and without that have beset me, I am able
+to appear before you again and tell you of advance.</p>
+
+<p class="ctr"><a href="./illustrations/11a.png"><img src=
+"./illustrations/11a_th.jpg" alt=" FIG. 1"></a></p>
+
+<p class="ctr">FIG. 1</p>
+
+<p>Practical men know well that there is a wide difference between
+a model and a full sized machine; and when I decided to construct a
+full sized tramcar and lay out a full sized track, I found it
+necessary to make many alterations of detail, my chief difficulty
+being so to design my work as to facilitate construction and allow
+of compensation for that inaccuracy of workmanship which I have
+come to regard as inevitable.</p>
+
+<p>In order to satisfy the directors of a tramway company of the
+practical nature of my system before disturbing their lines, I have
+laid, in a field near the works of Messrs. Smith, Baker &amp; Co.,
+Manchester, a track 110 yards long, 4 ft. 8&frac12; in. gauge, and
+I have constructed a full sized street tramcar to run thereon. My
+negotiations being with a company in a town where there are no
+steep gradients, and where the coefficient of friction of ordinary
+wheels would be sufficient for all tractive purposes, I thought it
+better to avoid the complication involved in employing a large
+central wheel with a broad surface specially designed for hilly
+districts, and with which I had mounted a gradient of one in
+sixteen.</p>
+
+<p class="ctr"><a href="./illustrations/11b.png"><img src=
+"./illustrations/11b_th.jpg" alt=" FIG. 2"></a></p>
+
+<p class="ctr">FIG. 2</p>
+
+<p>But as the line in question was laid with all the curves
+unnecessarily quick, even those in the "pass-bies," I thought it
+expedient to employ differential gear, as illustrated at D, Fig. 1,
+which is a sketch plan showing the mechanism employed. M is a
+Siemens electric motor running at 650 revolutions per minute; E is
+a combination of box gearing, frictional clutch, and chain pinion,
+and from this pinion a steel chain passes around the chain-wheel,
+H, which is free to revolve upon the axle, and carries within it
+the differential pinion, gearing with the bevel-wheel, B&sup2;,
+keyed upon the sleeve of the loose tram-wheel, T&sup2;, and with
+the bevel-wheel, B&sup1;, keyed upon the axle, to which the other
+tram-wheel, T&sup1;, is attached. To the other tram-wheels no gear
+is connected; one of them is fast to the axle, and the other runs
+loose, but to them the brake is applied in the usual manner.</p>
+
+<p>The electric current from the collector passes, by means of a
+copper wire, and a switch upon the dashboard of the car, and
+resistance coils placed under the seats, to the motor, and from the
+motor by means of an adjustable clip (illustrated in diagram, Fig.
+2) to the axles, and by them through the four wheels to the rails,
+which form the return circuit.</p>
+
+<p class="ctr"><a href="./illustrations/11c.png"><img src=
+"./illustrations/11c_th.jpg" alt=" FIG. 3"></a></p>
+
+<p class="ctr">FIG. 3</p>
+
+<p>I have designed many modifications of the track, but it is,
+perhaps, best at present to describe only that which I have in
+actual use, and it is illustrated in diagram, Fig. 3, which is a
+sectional and perspective view of the central channel. L is the
+surface of the road, and SS are the sleepers, CC are the chairs
+which hold the angle iron, AA forming the longitudinally slotted
+center rail and the electric lead, which consists of two half-tubes
+of copper insulated from the chairs by the blocks, I, I. A special
+brass clamp, free to slide upon the tube, is employed for this
+purpose, and the same form of clamp serves to join the two ends of
+the copper tubes together and to make electric contact. Two
+half-tubes instead of one slotted tube have been employed, in order
+to leave a free passage for dirt or wet to fall through the slot in
+the center rail to the drain space, G. Between chair and chair hewn
+granite or artificial stone is employed, formed, as shown in the
+drawing, to complete the surface of the road and to form a
+continuous channel or drain. In order that this drain may not
+become choked, at suitable intervals, in the length of the track,
+sump holes are formed as illustrated in diagram, Fig. 4 These sump
+holes have a well for the accumulation of mud, and are also
+connected with the main street drain, so that water can freely pass
+away. The hand holes afford facility for easily removing the
+dirt.</p>
+
+<p>In a complete track these hand holes would occasionally be wider
+than shown here, for the purpose of removing or fixing the
+collector, Fig. 5, which consists of two sets of spirally fluted
+rollers free to revolve upon spindles, which are held by
+knuckle-joints drawn together by spiral springs; by this means the
+pressure of the rollers against the inside of the tube is
+constantly maintained, and should any obstruction occur in the tube
+the spiral flute causes it to revolve, thus automatically cleansing
+the tubes.</p>
+
+<p class="ctr"><a href="./illustrations/11d.png"><img src=
+"./illustrations/11d_th.jpg" alt=" FIG. 4"></a></p>
+
+<p class="ctr">FIG. 4</p>
+
+<p>The collector is provided with two steel plates, which pass
+through the slit in the center rail; the lower ends of these plates
+are clamped by the upper frame of the collector, insulating
+material being interposed, and the upper ends are held in two iron
+cheeks. Between these steel plates insulated copper strips are
+held, electrically connected with the collector and with the
+adjustable clip mounted upon the iron cheeks; this clip holds the
+terminal on the end of the wire (leading to the motor) firmly
+enough for use, the cheeks being also provided with studs for the
+attachment of leather straps hooked on to the framework of the car,
+one for the forward and one for backward movement of the collector.
+These straps are strong enough for the ordinary haulage of the
+collector, and for the removal of pebbles and dirt that may get
+into the slit; but should any absolute block occur then they break
+and the terminal is withdrawn from the clip; the electric contact
+being thereby broken the car stops, the obstruction can then be
+removed and the collector reconnected without damage and with
+little delay.</p>
+
+<p class="ctr"><a href="./illustrations/11e.png"><img src=
+"./illustrations/11e_th.jpg" alt=" FIG. 5"></a></p>
+
+<p class="ctr">FIG. 5</p>
+
+<p>In order to secure continuity of the center rail throughout the
+length of the track, and still provide for the removal of the
+collector at frequent intervals, the framework of the collector is
+so made that, by slackening the side-bolts, the steel plates can be
+drawn upward and the collector itself withdrawn sideways through
+the hand holes, one of the half-tubes being removed for the
+purpose.</p>
+
+<p>Fig. 6 illustrates another arrangement that I have constructed,
+both of collector and method of collecting.</p>
+
+<p class="ctr"><a href="./illustrations/11f.png"><img src=
+"./illustrations/11f_th.jpg" alt=" FIG. 6"></a></p>
+
+<p class="ctr">FIG. 6</p>
+
+<p>As before mentioned, the arrangement now described has been
+carried out in a field near the works of Messrs. Smith, Baker &amp;
+Co., Cornbrook Telegraph Works, Manchester, and its working
+efficiency has been most satisfactory. After a week of rain and
+during drenching showers the car ran with the same speed and under
+the same control as when the ground was dry.</p>
+
+<p>This I account for by the theory that when the rails are wet and
+the tubes moist the better contact made compensates for the slight
+leakage that may occur.</p>
+
+<p>At the commencement of my paper I promised to confine myself to
+work done; I therefore abstain from describing various
+modifications of detail for the same purpose. But one method of
+supporting and insulating the conductor in the channel may be
+suggested by an illustration of the plan I adopted for a little
+pleasure line in the Winter Gardens, Blackpool.</p>
+
+<p class="ctr"><a href="./illustrations/12a.png"><img src=
+"./illustrations/12a_th.jpg" alt=" FIG. 7."></a></p>
+
+<p class="ctr">FIG. 7.</p>
+
+<p>Fig. 7. There the track being exclusively for the electric
+railway, it was not necessary to provide a center channel; the
+conductor has therefore been placed in the center of the track, and
+consists of bar iron 1&frac14; in. by &frac12; in., and is held
+vertically by means of studs riveted into the side; these studs
+pass through porcelain insulators, and by means of wooden clamps
+and wedges are held in the iron chairs which rest upon the
+sleepers. The iron conductors were placed vertically to facilitate
+bending round the sharp curves which were unavoidable on this
+line.</p>
+
+<p>The collector consists of two metal slippers held together by
+springs, attached to the car by straps and electrically connected
+to the motor by clips in the same manner as the one employed in
+Manchester.</p>
+
+<p>I am glad to say that, notwithstanding the curves with a radius
+of 55 feet and gradients of 1 in 57, this line is also a practical
+success.</p>
+
+<hr>
+<p><a name="23"></a></p>
+
+<h2>FIRES IN LONDON AND NEW YORK.</h2>
+
+<p>When the chief of the London Fire Brigade visited the United
+States in 1882, he was, as is the general rule on the other side of
+the Atlantic, "interviewed"&mdash;a custom, it may be remarked,
+which appears to be gaining ground also in this country. The
+inferences drawn from these interviews seem to be that the absence
+of large fires in London was chiefly due to the superiority of our
+fire brigade, and that the greater frequency of conflagrations in
+American cities, and particularly in New York, was due to the
+inferiority of their fire departments. How unjust such a comparison
+would be is shown in a paper presented by Mr. Edward B. Dorsey, a
+member of the American Society of Civil Engineers, to that
+association, in which the author discusses the comparative
+liability to and danger from conflagrations in London and in
+American cities. He found from an investigation which he conducted
+with much care during a visit to London that it is undoubtedly true
+that large fires are much less frequent in the metropolis than in
+American cities; but it is equally true that the circumstances
+existing in London and New York are quite different. As it is a
+well-known fact that the promptness, efficiency, and bravery of
+American firemen cannot be surpassed, we gladly give prominence to
+the result of the author's investigations into the true causes of
+the great liability of American cities to large fires. In a highly
+interesting comparison the writer has selected New York and London
+as typical cities, although his observations will apply to most
+American and English towns, if, perhaps, with not quite the same
+force. In the first place, the efforts of the London Fire Brigade
+receive much aid from our peculiarly damp climate. From the average
+of eleven years (1871-1881) of the meteorological observations made
+at the Greenwich Observatory, it appears that in London it rains,
+on the average, more than three days in the week, that the sun
+shines only one-fourth of the time he is above the horizon, and
+that the atmosphere only lacks 18 per cent. of complete saturation,
+and is cloudy seven-tenths of the time. Moreover, the humidity of
+the atmosphere in London is very uniform, varying but little in the
+different months. Under these circumstances, wood will not be
+ignited very easily by sparks or by contact with a weak flame. This
+is very different from the condition of wood in the long, hot, dry
+seasons of the American continent. The average temperature for the
+three winter months in London is 38.24 degrees Fahr.; in New York
+it is 31.56 degrees, or 6.68 degrees lower. This lower range of
+temperature must be the cause of many conflagrations, for, to make
+up for the deficiency in the natural temperature, there must be in
+New York many more and larger domestic fires. The following
+statistics, taken from the records of the New York Fire Department,
+show this. In the three winter months of 1881, January, February,
+and December, there were 522 fire alarms in New York, or an average
+per month of 174; in the remaining nine months 1,263, or an average
+per month of 140. In the corresponding three winter months of 1882
+there were 602 fire alarms, or an average per month of 201; in the
+remaining nine months 1,401, or an average per month of 155. In
+round numbers there were in 1881 one-fourth, and in 1882 one-third
+more fire alarms in the three winter months than in the nine warmer
+months. We are not aware that similar statistics have ever been
+compiled for London, and are consequently unable to draw
+comparison; but, speaking from recollection, fires appear to be
+more frequent also in London during the winter months.</p>
+
+<p>Another cause of the greater frequency of fires in New York and
+their more destructive nature is the greater density of population
+in that city. The London Metropolitan Police District covers 690
+square miles, extending 12 to 15 miles in every direction from
+Charing Cross, and contained in 1881 a population of 4,764,312; but
+what is generally known as London covers 122 square miles,
+containing, in 1881, 528,794 houses, and a population of 3,814,574,
+averaging 7.21 persons per house, 49 per acre, and 31,267 per
+square mile. Now let us look at New York. South of Fortieth Street
+between the Hudson and East Rivers, New York has an area of 3,905
+acres, a fraction over six square miles, exclusive of piers, and
+contained, according to the census of 1880, a population of
+813,076. This gives 208 persons per acre. The census of 1880
+reports the total number of dwellings in New York at 73,684; total
+population, 1,206,299; average per dwelling, 16.37. Selecting for
+comparison an area about equal from the fifteen most densely
+populated districts or parishes of London, of an aggregate area of
+3,896 acres, and with a total population of 746,305, we obtain
+191.5 persons per acre. Thus briefly New York averaged 208 persons
+per acre, and 16.37 per dwelling; London, for the same area, 191.5
+persons per acre, and 7.21 per house. But this comparison is
+scarcely fair, as in London only the most populous and poorest
+districts are included, corresponding to the entirely tenement
+districts of New York, while in the latter city it includes the
+richest and most fashionable sections, as well as the poorest. If
+tenement districts were taken alone, the population would be found
+much more dense, and New York proportionately much more densely
+populated. Taking four of the most thickly populated of the London
+districts (East London, Strand, Old Street, St. Luke's, St.
+Giles-in-the-Fields, and St. George, Bloomsbury), we find on a
+total area of 792 acres a population of 197,285, or an average of
+249 persons per acre. In four of the most densely populated wards
+of New York (10th, 11th, 13th, and 17th), we have on an area of 735
+acres a population of 258,966, or 352 persons per acre. This is 40
+per cent. higher than in London, the districts being about the same
+size, each containing about 1-1/5 square miles. Apart from the
+greater crowding which takes place in New York, and the different
+style of buildings, another very fertile cause of the spreading of
+fires is the freer use of wood in their construction. It is
+asserted that in New York there is more than double the quantity of
+wood used in buildings per acre than in London. From a house census
+undertaken in 1882 by the New York Fire Department, moreover, it
+appears that there were 106,885 buildings including sheds, of which
+28,798 houses were built of wood or other inflammable materials,
+besides 3,803 wooden sheds, giving a total of 32,601 wooden
+buildings.</p>
+
+<p>We are not aware that there are any wooden houses left in
+London. There are other minor causes which act as checks upon the
+spreading of fires in London. London houses are mostly small in
+size, and fires are thus confined to a limited space between brick
+walls. Their walls are generally low and well braced, which enable
+the firemen to approach them without danger. About 60 per cent. of
+London houses are less than 22 feet high from the pavement to the
+eaves; more than half of the remainder are less than 40 feet high,
+very few being over 50 feet high. This, of course, excludes the
+newer buildings in the City. St. James's Palace does not exceed 40
+feet, the Bank of England not over 30 feet in height; but these are
+exceptional structures. Fireproof roofings and projecting party
+walls also retard the spreading of conflagrations. The houses being
+comparatively low and small, the firemen are enabled to throw water
+easily over them, and to reach their roofs with short ladders.
+There is in London an almost universal absence of wooden additions
+and outbuildings, and the New York ash barrel or box kept in the
+house is also unknown. The local authorities in London keep a
+strict watch over the manufacture or storage of combustible
+materials in populous parts of the city. Although overhead
+telegraph wires are multiplying to an alarming extent in London,
+their number is nothing to be compared to their bewildering
+multitude in New York, where their presence is not only a
+hinderance to the operations of the firemen, but a positive danger
+to their lives. Finally&mdash;and this has already been partly
+dealt with in speaking of the comparative density of population of
+the two cities&mdash;a look at the map of London will show us how
+the River Thames and the numerous parks, squares, private grounds,
+wide streets, as well as the railways running into London, all act
+as effectual barriers to the extension of fires.</p>
+
+<p>The recent great conflagrations in the city vividly illustrate
+to Londoners what fire could do if their metropolis were built on
+the New York plan. The City, however, as we have remarked, is an
+exceptional part of London, and, taking the British metropolis as
+it is, with its hundreds of square miles of suburbs, and
+contrasting its condition with that of New York, we are led to
+adopt the opinion that London, with its excellent fire brigade, is
+safe from a destructive conflagration. It was stated above, and it
+is repeated here, that the fire brigade of New York is unsurpassed
+for promptness, skill, and heroic intrepidity, but their task, by
+contrast, is a heavy one in a city like New York, with its numerous
+wooden buildings, wooden or asphalt roofs, buildings from four to
+ten stories high, with long unbraced walls, weakened by many large
+windows, containing more than ten times the timber an average
+London house does, and that very inflammable, owing to the dry and
+hot American climate. But this is not all. In New York we find the
+five and six story tenement houses with two or three families on
+each floor, each with their private ash barrel or box kept handy in
+their rooms, all striving to keep warm during the severe winters of
+North America. We also find narrow streets and high buildings, with
+nothing to arrest the extension of a fire except a few small parks,
+not even projecting or effectual fire-walls between the several
+buildings. And to all this must be added the perfect freedom with
+which the city authorities of New York allow in its most populous
+portions large stables, timber yards, carpenters' shops, and the
+manufacture and storage of inflammable materials. Personal liberty
+could not be carried to a more dangerous extent. We ought to be
+thankful that in such matters individual freedom is somewhat
+hampered in our old-fashioned and quieter-going
+country.&mdash;<i>London Morning Post</i>.</p>
+
+<hr>
+<p><a name="18"></a></p>
+
+<h2>THE LATEST KNOWLEDGE ABOUT GAPES.</h2>
+
+<p>The gape worm may be termed the <i>bete noir</i> of the
+poultry-keeper&mdash;his greatest enemy&mdash;whether he be farmer
+or fancier. It is true there are some who declare that it is
+unknown in their poultry-yards&mdash;that they have never been
+troubled with it at all. These are apt to lay it down, as I saw a
+correspondent did in a recent number of the <i>Country
+Gentleman</i>, that the cause is want of cleanliness or neglect in
+some way. But I can vouch that that is not so. I have been in yards
+where everything was first-rate, where the cleanliness was almost
+painfully complete, where no fault in the way of neglect could be
+found, and yet the gapes were there; and on the other hand, I have
+known places where every condition seemed favorable to the
+development of such a disease, and there it was absent&mdash;this
+not in isolated cases, but in many. No, we must look elsewhere for
+the cause.</p>
+
+<p>Observations lead me to the belief that gapes are more than
+usually troublesome during a wet spring or summer following a mild
+winter. This would tend to show that the egg from which the worm
+(that is in itself the disease) emerges is communicated from the
+ground, from the food eaten, or the water drunk, in the first
+instance, but it is more than possible that the insects themselves
+may pass from one fowl to another. All this we can accept as a
+settled fact, and also any description of the way in which the
+parasitic worms attach themselves to the throats of the birds, and
+cause the peculiar gaping of the mouth which gives the name to the
+disease.</p>
+
+<p>Many remedies have been suggested, and my object now is to
+communicate some of the later ones&mdash;thus to give a variety of
+methods, so that in case of the failure of one, another will be at
+hand ready to be tried. It is a mistake always to pin the faith to
+one remedy, for the varying conditions found in fowls compel a
+different treatment. The old plan of dislodging the worms with a
+feather is well known, and need not be described again. But I may
+mention that in this country some have found the use of an
+ointment, first suggested by Mr. Lewis Wright, I believe, most
+valuable. This is made of mercurial ointment, two parts; pure lard,
+two parts; flour of sulphur, one part; crude petroleum, one
+part&mdash;and when mixed together is applied to the heads of the
+chicks as soon as they are dry after hatching. Many have testified
+that they have never found this to fail as a preventive, and if the
+success is to be attributed to the ointment, it would seem as if
+the insects are driven off by its presence, for the application to
+the heads merely would not kill the eggs.</p>
+
+<p>Some time ago Lord Walsingham offered, through the Entomological
+Society of London, a prize for the best life history of the gapes
+disease, and this has been won by the eminent French scientist M.
+Pierre M&eacute;gnin, whose essay has been published by the noble
+donor. His offer was in the interest of pheasant breeders, but the
+benefit is not confined to that variety of game alone, for it is
+equally applicable to all gallinaceous birds troubled with this
+disease. The pamphlet in question is a very valuable work, and
+gives very clearly the methods by which the parasite develops. But
+for our purpose it will be sufficient to narrate what M.
+M&eacute;gnin recommends for the cure of it. These are various, as
+will be seen, and comprise the experience of other inquirers as
+well as himself.</p>
+
+<p>He states that Montague obtained great success by a combination
+of the following methods: Removal from infested runs; a thorough
+change of food, hemp seed and green vegetables figuring largely in
+the diet; and for drinking, instead of plain water, an infusion of
+rue and garlic. And M&eacute;gnin himself mentions an instance of
+the value of garlic. In the years 1877 and 1878, the pheasant
+preserves of Fontainebleau were ravaged by gapes. The disease was
+there arrested and totally cured, when a mixture, consisting of
+yolks of eggs, boiled bullock's heart, stale bread crumbs, and
+leaves of nettle, well mixed and pounded together with garlic, was
+given, in the proportion of one clove to ten young pheasants. The
+birds were found to be very fond of this mixture, but great care
+was taken to see that the drinking vessels were properly cleaned
+out and refilled with clean, pure water twice a day. This treatment
+has met with the same success in other places, and if any of your
+readers are troubled with gapes and will try it, I shall be pleased
+to see the results narrated in the columns of the <i>Country
+Gentleman</i>. Garlic in this case is undoubtedly the active
+ingredient, and as it is volatile, when taken into the stomach the
+breath is charged with it, and in this way (for garlic is a
+powerful vermifuge) the worms are destroyed.</p>
+
+<p>Another remedy recommended by M. M&eacute;gnin was the strong
+smelling vermifuge assafoetida, known sometimes by the suggestive
+name of "devil's dung." It has one of the most disgusting oders
+possible, and is not very pleasant to be near. The assafoetida was
+mixed with an equal part of powdered yellow gentian, and this was
+given to the extent of about 8 grains a day in the food. As an
+assistance to the treatment, with the object of killing any embryos
+in the drinking water, fifteen grains of salicylate of soda was
+mixed with a pint and three-quarters of water. So successful was
+this, that on M. De Rothschild's preserves at Rambouillet, where a
+few days before gapes were so virulent that 1,200 pheasants were
+found dead every morning, it succeeded in stopping the epidemic in
+a few days. But to complete the matter, M. M&eacute;gnin adds that
+it is always advisable to disinfect the soil of preserves. For this
+purpose, the best means of destroying any eggs or embryos it may
+contain is to water the ground with a solution of sulphuric acid,
+in the proportion of a pennyweight to three pints of water, and
+also birds that die of the disease should be deeply buried in
+lime.</p>
+
+<p>Fumigation with carbolic acid is an undoubted cure, but then it
+is a dangerous one, and unless very great care is taken in killing
+the worms, the bird is killed also. Thus many find this a risky
+method, and prefer some other. Lime is found to be a valuable
+remedy. In some districts of England, where lime-kilns abound, it
+is a common thing to take children troubled with whooping-cough
+there. Standing in the smoke arising from the kilns, they are
+compelled to breathe it. This dislodges the phlegm in the throat,
+and they are enabled to get rid of it. Except near lime-kilns, this
+cannot be done to chickens, but fine slaked lime can be used,
+either alone or mixed with powdered sulphur, two parts of the
+former to one of the latter. The air is charged with this fine
+powder, and the birds, breathing it, cough, and thus get rid of the
+worms, which are stupefied by the lime, and do not retain so firm a
+hold on the throat. An apparatus has recently been introduced to
+spread this lime powder. It is in the form of an air-fan, with a
+pointed nozzle, which is put just within the coop at night, when
+the birds are all within. The powder is already in a compartment
+made for it, and by the turning of a handle, it is driven through
+the nozzle, and the air within the coop charged with it. There is
+no waste of powder, nor any fear that it will not be properly
+distributed. Experienced pheasant and poultry breeders state that
+by the use of this once a week, gapes are effectually prevented. In
+this case, also, I shall be glad to learn the result if tried.</p>
+
+<p>STEPHEN BEALE.</p>
+
+<p>H&mdash;&mdash;, Eng., Aug. 1.</p>
+
+<p>&mdash;<i>Country Gentleman</i>.</p>
+
+<hr>
+<p><a name="1"></a></p>
+
+<h2>WOLPERT'S METHOD OF ESTIMATING THE AMOUNT OF CARBONIC ACID IN
+THE AIR</h2>
+
+.
+
+<p>There is a large number of processes and apparatus for
+estimating the amount of carbonic acid in the air. Some of them,
+such as those of Regnault, Reiset, the Montsouris observers (Fig.
+1), and Brand, are accurate analytical instruments, and
+consequently quite delicate, and not easily manipulated by
+hygienists of middling experience. Others are less complicated, and
+also less exact, but still require quite a troublesome
+manipulation&mdash;such, for example, as the process of
+Pettenkofer, as modified by Fodor, that of Hesse, etc.</p>
+
+<p class="ctr"><a href="./illustrations/13a.png"><img src=
+"./illustrations/13a_th.jpg" alt=
+" APPARATUS FOR ESTIMATING THE CARBONIC ACID OF THE AIR."></a></p>
+
+<p class="ctr">APPARATUS FOR ESTIMATING THE CARBONIC ACID OF THE
+AIR. 3.&mdash;Bertin-Sans Apparatus. FIG. 4.&mdash;Bubbling Glass.
+FIG. 5.&mdash;Pipette. FIG. 6.&mdash;Arrangement of the U-shaped
+Tube. FIG. 7.&mdash;Wolpert's Apparatus.</p>
+
+<p>Hygienists have for some years striven to obtain some very
+simple apparatus (rather as an indicator than an analytical
+instrument) that should permit it to be quickly ascertained whether
+the degree of impurity of a place was incompatible with health, and
+in what proportion it was so. It is from such efforts that have
+resulted the processes of Messrs. Smith. Lunge, Bertin-Sans, and
+the apparatus of Prof. Wolpert (Fig. 7).</p>
+
+<p>It is of the highest interest to ascertain the proportion of
+carbonic acid in the air, and especially in that of inhabited
+places, since up to the present this is the best means of finding
+out how much the air that we are breathing is polluted, and whether
+there is sufficient ventilation or not. Experiment has, in fact,
+demonstrated that carbonic acid increases in the air of inhabited
+rooms in the same way as do those organic matters which are
+difficult of direct estimation. Although a few ten-thousandths more
+of carbonic acid in our air cannot of themselves endanger us, yet
+they have on another hand a baneful significance, and, indeed, the
+majority of hygienists will not tolerate more than six
+ten-millionths of this element in the air of dwellings, and some of
+them not more than five ten-millionths.</p>
+
+<p>Carbonic acid readily betrays its presence through solutions of
+the alkaline earths such as baryta and chalk, in which its passage
+produces an insoluble carbonate, and consequently makes the liquid
+turbid. If, then, one has prepared a solution of baryta or lime, of
+which a certain volume is made turbid by the passage of a likewise
+known volume of CO<sub>2</sub>, it will be easy to ascertain how
+much CO<sub>2</sub> a certain air contains, from the volume of the
+latter that it will be necessary to pass through the basic solution
+in order to obtain the amount of turbidity that has been taken as a
+standard. The problem consists in determining the minimum of air
+required to make the known solution turbid. Hence the name
+"minimetric estimation," that has been given to this process. Prof.
+Lescoeur has had the goodness to construct for me a Smith's
+minimetric apparatus (Fig. 2) with the ingenious improvements that
+have been made in it by Mr. Fischli, assistant to Prof. Weil, of
+Zurich. I have employed it frequently, and I use it every year in
+my lectures. I find it very practical, provided one has got
+accustomed to using it. It is, at all events, of much simpler
+manipulation than that of Bertin-Sans, although the accuracy of the
+latter may be greater (Figs. 3, 4, 5, and 6). But it certainly has
+more than one defect, and some of the faults that have been found
+with it are quite serious. The worst of these consists in the
+difficulty of catching the exact moment at which the turbidity of
+the basic liquid is at the proper point for arresting the
+operation. In addition to this capital defect, it is regrettable
+that it is necessary to shake the flask that contains the solution
+after every insufflation of air, and also that the play of the
+valves soon becomes imperfect. Finally, Mr. Wolpert rightly sees
+one serious drawback to the use of baryta in an apparatus that has
+to be employed in schools, among children, and that is that this
+substance is poisonous. This gentleman therefore replaces the
+solution of baryta by water saturated with lime, which costs almost
+nothing, and the preparation of which is exceedingly simple.
+Moreover, it is a harmless agent.</p>
+
+<p>The apparatus consists of two parts. The first of these is a
+glass tube closed at one end, and 12 cm. in length by 12 mm. in
+diameter. Its bottom is of porcelain, and bears on its inner
+surface the date 1882 in black characters. Above, and at the level
+that corresponds to a volume of three cubic centimeters, there is a
+black line which serves as an invariable datum point. A rubber bulb
+of twenty-eight cubic centimeters capacity is fixed to a tube which
+reaches its bottom, and is flanged at the other extremity (Fig.
+7).</p>
+
+<p>The operation is as follows:</p>
+
+<p>The saturated, but limpid, solution of lime is poured into the
+first tube up to the black mark, the tube of the air bulb is
+introduced into the lime water in such a way that its orifice shall
+be in perfect contact with the bottom of the other tube, and then,
+while the bulb is held between the fore and middle fingers of the
+upturned hand, one presses slowly with the thumb upon its bottom so
+as to expel all the air that it contains. This air enters the
+lime-water bubble by bubble. After this the tube is removed from
+the water, and the bulb is allowed to fill with air, and the same
+maneuver is again gone through with. This is repeated until the
+figures 1882, looked at from above, cease to be clearly visible,
+and disappear entirely after the contents of the tube have been
+vigorously shaken.</p>
+
+<p>The measures are such that the turbidity supervenes at once if
+the air in the bulb contains twenty thousandths of CO<sub>2</sub>.
+If it becomes necessary to inject the contents of the bulb into the
+water twice, it is clear that the proportion is only ten
+thousandths; and if it requires ten injections the air contains ten
+times less CO<sub>2</sub> than that having twenty thousandths, or
+only two per cent. A table that accompanies the apparatus has been
+constructed upon this basis, and does away with the necessity of
+making calculations.</p>
+
+<p>An air that contained ten thousandths of CO<sub>2</sub>, or even
+five, would be almost as deleterious, in my opinion, as one of two
+per cent. It is of no account, then, to know the proportions
+intermediate to these round numbers. Yet it is possible, if the
+case requires it, to obtain an indication between two consecutive
+figures of the scale by means of another bulb whose capacity is
+only half that of the preceding. Thus, two injections of the large
+bulb, followed by one of the small, or two and a half injections,
+correspond to a richness of 8 thousandths of CO<sub>2</sub>; and
+5&frac12; to 3.6 thousandths. This half-bulb serves likewise for
+another purpose. From the moment that the large bulb makes the
+lime-water turbid with an air containing two per cent. of
+CO<sub>2</sub>, it is clear that the small one can cause the same
+turbidity only with air twice richer in CO<sub>2</sub>,
+<i>i.e</i>., of four per cent.</p>
+
+<p>This apparatus, although it makes no pretensions to extreme
+accuracy, is capable of giving valuable information. The table that
+accompanies it is arranged for a temperature of 17&deg; and a
+pressure of 740 mm. But different meteorological conditions do not
+materially alter the results. Thus, with 10&deg; less it would
+require thirty-one injections instead of thirty, and CO<sub>2</sub>
+would be 0.64 per 1,000 instead of 0.66; and with 10&deg; more,
+thirty injections instead of thirty one.</p>
+
+<p>The apparatus is contained in a box that likewise holds a bottle
+of lime-water sufficient for a dozen analyses, the table of
+proportions of CO<sub>2</sub>, and the apparatus for cleaning the
+tubes. The entire affair is small enough to be carried in the
+pocket.&mdash;<i>J. Arnould, in Science et Nature</i>.</p>
+
+<hr>
+<p>[NATURE.]</p>
+
+<p><a name="19"></a></p>
+
+<h2>THE VOYAGE OF THE VETTOR PISANI.</h2>
+
+<p>Knowing how much <i>Nature</i> is read by all the naturalists of
+the world, I send these few lines, which I hope will be of some
+interest.</p>
+
+<p>The Italian R.N. corvette Vettor Pisani left Italy in April,
+1882, for a voyage round the world with the ordinary commission of
+a man-of-war. The Minister of Marine, wishing to obtain scientific
+results, gave orders to form, when possible, a marine zoological
+collection, and to carry on surveying, deep-sea soundings, and
+abyssal thermometrical measurements. The officers of the ship
+received their different scientific charges, and Prof. Dohrn,
+director of the Zoological Station at Naples, gave to the writer
+necessary instructions for collecting and preserving sea
+animals.</p>
+
+<p>At the end of 1882 the Vettor Pisani visited the Straits of
+Magellan, the Patagonian Channels, and Chonos and Chiloe islands;
+we surveyed the Darwin Channel, and following Dr. Cuningham's work
+(who visited these places on board H.M.S. Nassau), we made a
+numerous collection of sea animals by dredging and fishing along
+the coasts.</p>
+
+<p>While fishing for a big shark in the Gulf of Panama during the
+stay of our ship in Taboga Island, one day in February, with a dead
+clam, we saw several great sharks some miles from our anchorage. In
+a short time several boats with natives went to sea, accompanied by
+two of the Vettor Pisani's boats.</p>
+
+<p>Having wounded one of these animals in the lateral part of the
+belly, we held him with lines fixed to the spears; he then began to
+describe a very narrow curve, and irritated by the cries of the
+people that were in the boats, ran off with a moderate velocity. To
+the first boat, which held the lines just mentioned, the other
+boats were fastened, and it was a rather strange emotion to feel
+ourselves towed by the monster for more than three hours with a
+velocity that proved to be two miles per hour. One of the boats was
+filled with water. At last the animal was tired by the great loss
+of blood, and the boats assembled to haul in the lines and tow the
+shark on shore.</p>
+
+<p>With much difficulty the nine boats towed the animal alongside
+the Vettor Pisani to have him hoisted on board, but it was
+impossible on account of his colossal dimensions. But as it was
+high water we went toward a sand beach with the animal, and we had
+him safely stranded at night.</p>
+
+<p>With much care were inspected the mouth, the nostrils, the ears,
+and all the body, but no parasite was found. The eyes were taken
+out and prepared for histological study. The set of teeth was all
+covered by a membrane that surrounded internally the lips; the
+teeth are very little, and almost in a rudimental state. The mouth,
+instead of opening in the inferior part of the head, as in common
+sharks, was at the extremity of the head; the jaws having the same
+bend.</p>
+
+<p>Cutting the animal on one side of the backbone we met (1) a
+compact layer of white fat 20 centimeters deep; (2) the
+cartilaginous ribs covered with blood vessels; (3) a stratum of
+flabby, stringy, white muscle, 60 centimeters high, apparently in
+adipose degeneracy; (4) the stomach.</p>
+
+<p>By each side of the backbone he had three chamferings, or
+flutings, that were distinguished by inflected interstices. The
+color of the back was brown with yellow spots that became close and
+small toward the head, so as to be like marble spots. The length of
+the shark was 8.90 m. from the mouth to the <i>pinna caudalis</i>
+extremity, the greatest circumference 6.50 m., and 2.50 m. the main
+diameter (the outline of the two projections is made for giving
+other dimensions).</p>
+
+<p>The natives call the species <i>Tintoreva</i>, and the most aged
+of the village had only once before fished such an animal, but
+smaller. While the animal was on board we saw several <i>Remora</i>
+about a foot long drop from his mouth; it was proved that these
+fish lived fixed to the palate, and one of them was pulled off and
+kept in the zoological collection of the ship.</p>
+
+<p>The Vettor Pisani has up the present visited Gibraltar, Cape
+Verde Islands, Pernambuco, Rio Janeiro, Monte Video, Valparaiso,
+many ports of Peru, Guayaquil, Panama, Galapagos Islands, and all
+the collections were up to this sent to the Zoological Station at
+Naples to be studied by the naturalists. By this time the ship left
+Callao for Honolulu, Manila, Hong Kong, and, as the Challenger had
+not crossed the Pacific Ocean in these directions, we made several
+soundings and deep-sea thermometrical measurements from Callao to
+Honolulu. Soundings are made with a steel wire (Thompson system)
+and a sounding-rod invented by J. Palumbo, captain of the ship. The
+thermometer employed is a Negretti and Zambra deep-sea thermometer,
+improved by Captain Maguaghi (director of the Italian R.N.
+Hydrographic Office).</p>
+
+<p>With the thermometer wire has always been sent down a tow-net
+which opens and closes automatically, also invented by Captain
+Palumbo. This tow-net has brought up some little animals that I
+think are unknown.</p>
+
+<p>G. CHIERCHIA.</p>
+
+<p>Honolulu July 1.</p>
+
+<p>The shark captured by the Vettor Pisani in the Gulf of Panama is
+<i>Rhinodon typicus</i>, probably the most gigantic fish in
+existence. Mr. Swinburne Ward, formerly commissioner of the
+Seychelles, has informed me that it attains to a length of 50 feet
+or more, which statement was afterward confirmed by Prof. E.P.
+Wright. Originally described by Sir A. Smith from a single specimen
+which was killed in the neighborhood of Cape Town, this species
+proved to be of not uncommon occurrence in the Seychelles
+Archipelago, where it is known by the name of "Chagrin." Quite
+recently Mr. Haly reported the capture of a specimen on the coast
+of Ceylon. Like other large sharks (<i>Carcharodon rondeletii,
+Selache maxima</i>, etc.), Rhinodon has a wide geographical range,
+and the fact of its occurrence on the Pacific coast of America,
+previously indicated by two sources, appears now to be fully
+established. T. Gill in 1865 described a large shark known in the
+Gulf of California by the name of "Tiburon ballenas" or
+whale-shark, as a distinct genus&mdash;<i>Micristodus
+punctatus</i>&mdash;which, in my opinion, is the same fish. And
+finally, Prof. W. Nation examined in 1878 a specimen captured at
+Callao. Of this specimen we possess in the British Museum a portion
+of the dental plate. The teeth differ in no respect from those of a
+Seychelles Chagrin; they are conical, sharply pointed, recurved,
+with the base of attachment swollen. Making no more than due
+allowance for such variations in the descriptions by different
+observers as are unavoidable in accounts of huge creatures examined
+by some in a fresh, by others in a preserved, state, we find the
+principal characteristics identical in all these accounts, viz.:
+the form of the body, head, and snout, relative measurements,
+position of mouth, nostrils, and eyes, dentition, peculiar ridges
+on the side of the trunk and tail, coloration, etc. I have only to
+add that this shark is stated to be of mild disposition and quite
+harmless. Indeed, the minute size of its teeth has led to the
+belief in the Seychelles that it is a herbivorous fish, which,
+however, is not probable.</p>
+
+<p>ALBERT GUNTHER.</p>
+
+<p>Natural History Museum, <i>July 30</i>.</p>
+
+<hr>
+<p><a name="24"></a></p>
+
+<h2>THE GREELY ARCTIC EXPEDITION.</h2>
+
+<p class="ctr"><a href="./illustrations/14a.png"><img src=
+"./illustrations/14a_th.jpg" alt=
+" THE GREELY ARCTIC EXPEDITION.&mdash;THE FARTHEST POINT"></a></p>
+
+<p class="ctr">THE GREELY ARCTIC EXPEDITION.&mdash;THE FARTHEST
+POINT NORTH.</p>
+
+<p>Some account has been given of the American Meteorological
+Expedition, commanded by Lieutenant, now Major, Greely, of the
+United States Army, in the farthest north channels, beyond Smith
+Sound, that part of the Arctic regions where the British Polar
+expedition, in May, 1876, penetrated to within four hundred
+geographical miles of the North Pole. The American expedition, in
+1883, succeeded in getting four miles beyond, this being effected
+by a sledge party traveling over the snow from Fort Conger, the
+name they had given to their huts erected on the western shore near
+Discovery Cove, in Lady Franklin Sound. The farthest point reached,
+on May 18, was in latitude 83 deg. 24 min. N.; longitude 40 deg. 46
+min. W., on the Greenland coast. The sledge party was commanded by
+Lieutenant Lockwood, and the following particulars are supplied by
+Sergeant Brainerd, who accompanied Lieutenant Lockwood on the
+expedition. During their sojourn in the Arctic regions the men were
+allowed to grow the full beard, except under the mouth, where it
+was clipped short. They wore knitted mittens, and over these heavy
+seal-skin mittens were drawn, connected by a tanned seal-skin
+string that passed over the neck, to hold them when the hands were
+slipped out. Large tanned leather pockets were fastened outside the
+jackets, and in very severe weather jerseys were sometimes worn
+over the jackets for greater protection against the intense cold.
+On the sledge journeys the dogs were harnessed in a fan-shaped
+group to the traces, and were never run tandem. In traveling, the
+men were accustomed to hold on to the back of the sledge, never
+going in front of the team, and often took off their heavy
+overcoats and threw them on the load. When taking observations with
+the sextant, Lieutenant Lockwood generally reclined on the snow,
+while Sergeant Brainerd called time and made notes, as shown in our
+illustration. When further progress northward was barred by open
+water, and the party almost miraculously escaped drifting into the
+Polar sea, Lieutenant Lockwood erected, at the highest point of
+latitude reached by civilized man, a pyramidal-shaped cache of
+stones, six feet square at the base, and eight or nine feet high.
+In a little chamber about a foot square half-way to the apex, and
+extending to the center of the pile, he placed a self-recording
+spirit thermometer, a small tin cylinder containing records of the
+expedition, and then sealed up the aperture with a closely fitting
+stone. The cache was surmounted with a small American flag made by
+Mrs. Greely, but there were only thirteen stars, the number of the
+old revolutionary flag. From the summit of Lockwood Island, the
+scene presented in our illustration, 2,000 feet above the sea,
+Lieutenant Lockwood was unable to make out any land to the north or
+the northwest. "The awful panorama of the Arctic which their
+elevation spread out before them made a profound impression upon
+the explorers. The exultation which was natural to the achievement
+which they found they had accomplished was tempered by the
+reflections inspired by the sublime desolation of that stern and
+silent coast and the menace of its unbroken solitude. Beyond to the
+eastward was the interminable defiance of the unexplored
+coast&mdash;black, cold, and repellent. Below them lay the Arctic
+Ocean, buried beneath frozen chaos. No words can describe the
+confusion of this sea of ice&mdash;the hopeless asperity of it, the
+weariness of its torn and tortured surface. Only at the remote
+horizon did distance and the fallen snow mitigate its roughness and
+soften its outlines; and beyond it, in the yet unattainable
+recesses of the great circle, they looked toward the Pole itself.
+It was a wonderful sight, never to be forgotten, and in some degree
+a realization of the picture that astronomers conjure to themselves
+when the moon is nearly full, and they look down into the great
+plain which is called the Ocean of Storms, and watch the shadows of
+sterile and airless peaks follow a slow procession across its
+silver surface."&mdash;<i>Illustrated London News</i>.</p>
+
+<hr>
+<p><a name="25"></a></p>
+
+<h2>THE NILE EXPEDITION.</h2>
+
+<p class="ctr"><a href="./illustrations/14b.png"><img src=
+"./illustrations/14b_th.jpg" alt=" WHALER GIG FOR THE NILE.">
+</a></p>
+
+<p class="ctr">WHALER GIG FOR THE NILE.</p>
+
+<p>As soon as the authorities had finally made up their minds to
+send a flotilla of boats to Cairo for the relief of Khartoum, not a
+moment was lost in issuing orders to the different shipbuilding
+contractors for the completion, with the utmost dispatch, of the
+400 "whaler-gigs" for service on the Nile. They are light-looking
+boats, built of white pine, and weigh each about 920 lb., that is
+without the gear, and are supposed to carry four tons of
+provisions, ammunition, and camp appliances, the food being
+sufficient for 100 days. The crew will number twelve men, soldiers
+and sailors, the former rowing, while the latter (two) will attend
+the helm. Each boat will be fitted with two lug sails, which can be
+worked reefed, so as to permit an awning to be fitted underneath
+for protection to the men from the sun. As is well known, the wind
+blows for two or three months alternately up and down the Nile, and
+the authorities expect the flotilla will have the advantage of a
+fair wind astern for four or five days at the least. On approaching
+the Cataracts, the boats will be transported on wooden rollers over
+the sand to the next level for relaunching.</p>
+
+<hr>
+<p><a name="20"></a></p>
+
+<h2>THE PROPER TIME FOR CUTTING TIMBER.</h2>
+
+<h3><i>To the Editor of the Oregonian:</i></h3>
+
+<p>Believing that any ideas relating to this matter will be of some
+interest to your readers in this heavily-timbered region, I
+therefore propose giving you my opinion and conclusions arrived at
+after having experimented upon the cutting and use of timber for
+various purposes for a number of years here upon the Pacific
+coast.</p>
+
+<p>This, we are all well aware, is a very important question, and
+one very difficult to answer, since it requires observation and
+experiment through a course of many years to arrive at any definite
+conclusion; and it is a question too upon which even at the present
+day there exists a great difference of opinion among men who, being
+engaged in the lumber business, are thereby the better qualified to
+form an opinion.</p>
+
+<p>Many articles have been published in the various papers of the
+country upon this question for the past thirty years, but in all
+cases an opinion only has been given, which, at the present day,
+such is the advance and higher development of the intellectual
+faculties of man, that a mere opinion upon any question without
+sufficient and substantial reasons to back it is of little
+value.</p>
+
+<p>My object in writing this is not simply to give an opinion, but
+how and the methods used by which I adopted such conclusions, as
+well also as the reasons why timber is more durable and better when
+cut at a certain season of the year than when cut at any other.</p>
+
+<p>In the course of my investigations of this question for the past
+thirty years, I have asked the opinion of a great many persons who
+have been engaged in the lumber business in various States of the
+Union, from Maine to Wisconsin, and they all agree upon one point,
+viz., that the winter time is the proper time for cutting timber,
+although none has ever been able to give a reason why, only the
+fact that such was the case, and therefore drawing the inference
+that it was the proper time when timber should be cut; and so it
+is, for one reason only, however, and that is the convenience for
+handling or moving timber upon the snow and ice.</p>
+
+<p>It was while engaged in the business of mining in the mountains
+of California in early days, and having occasion to work often
+among timber, in removing stumps, etc., it was while so engaged
+that I noticed one peculiar fact, which was this&mdash;that the
+stumps of some trees which had been cut but two or three years had
+decayed, while others of the same size and variety of pine which
+had been cut the same year were as sound and firm as when first
+cut. This seemed strange to me, and I found upon inquiry of old
+lumbermen who had worked among timber all their lives, that it was
+strange to them also, and they could offer no explanation; and it
+was the investigation of this singular fact that led me to
+experiment further upon the problem of cutting timber.</p>
+
+<p>It was not, however, until many years after, and when engaged in
+clearing land for farming purposes, that I made the discovery why
+some stumps should decay sooner than others of the same size and
+variety, even when cut a few months afterward.</p>
+
+<p>I had occasion to clear several acres of land which was covered
+with a very dense growth of young pines from two to six inches in
+diameter (this work for certain reasons is usually done in the
+winter). The young trees, not being suitable for fuel, are thrown
+into piles and burned upon the ground. Such land, therefore, on
+account of the stumps is very difficult to plow, as the stumps do
+not decay for three or four years, while most of the larger ones
+remain sound even longer.</p>
+
+<p>But, for the purpose of experimenting, I cleaned a few acres of
+ground in the spring, cutting them in May and June. I trimmed the
+poles, leaving them upon the ground, and when seasoned hauled them
+to the house for fuel, and found that for cooking or heating
+purposes they were almost equal to oak; and it was my practice for
+many years afterward to cut these young pines in May or June for
+winter fuel.</p>
+
+<p>I found also that the stumps, instead of remaining sound for any
+length of time, decayed so quickly that they could all be plowed up
+the following spring.</p>
+
+<p>From which facts I draw these conclusions: that if in the
+cutting of timber the main object is to preserve the stumps, cut
+your trees in the fall or winter; but if the value of the timber is
+any consideration, cut your trees in the spring after the sap has
+ascended the tree, but before any growth has taken place or new
+wood has been formed.</p>
+
+<p>I experimented for many years also in the cutting of timber for
+fencing, fence posts, etc., and with the same results. Those which
+were cut in the spring and set after being seasoned were the most
+durable, such timber being much lighter, tougher, and in all
+respects better for all variety of purposes.</p>
+
+<p>Having given some little idea of the manner in which I
+experimented, and the conclusions arrived at as to the proper time
+when timber should be cut, I now propose to give what are, in my
+opinion, the reasons why timber cut in early summer is much better,
+being lighter, tougher and more durable than if cut at any other
+time. Therefore, in order to do this it is necessary first to
+explain the nature and value of the sap and the growth of a
+tree.</p>
+
+<p>We find it to be the general opinion at present, as it perhaps
+has always been among lumbermen and those who work among timber,
+that the sap of a tree is an evil which must be avoided if
+possible, for it is this which causes decay and destroys the life
+and good qualities of all wood when allowed to remain in it for an
+unusual length of time, but that this is a mistaken idea I will
+endeavor to show, not that the decay is due to the sap, but to the
+time when the tree was felled.</p>
+
+<p>We find by experiment in evaporating a quantity of sap of the
+pine, that it is water holding in solution a substance of a gummy
+nature, being composed of albumen and other elementary matters,
+which is deposited within the pores of the wood from the new growth
+of the tree; that these substances in solution, which constitute
+the sap, and which promote the growth of the tree, should have a
+tendency to cause decay of the wood is an impossibility. The injury
+results from the water only, and the improper time of felling the
+tree.</p>
+
+<p>Of the process in which the sap promotes the growth of the tree,
+the scientist informs us that it is extracted from the soil, and
+flows up through the pores of the wood of the tree, where it is
+deposited upon the fiber, and by a peculiar process of nature the
+albumen forms new cells, which in process of formation crowd and
+push out from the center, thus constituting the growth of the tree
+in all directions from center to circumference. Consequently this
+new growth of wood, being composed principally of albumen, is of a
+soft, spongy nature, and under the proper conditions will decay
+very rapidly, which can be easily demonstrated by experiment.</p>
+
+<p>Hence, we must infer that the proper time for felling the tree
+is when the conditions are such that the rapid decay of a new
+growth of wood is impossible; and this I have found by experiment
+to be in early summer, after the sap has ascended the tree, but
+before any new growth of wood has been formed. The new growth of
+the previous season is now well matured, has become hard and firm,
+and will not decay. On the contrary, the tree being cut when such
+new growth has not well matured, decay soon takes place, and the
+value of the timber is destroyed. The effect of this cutting and
+use of timber under the wrong conditions can be seen all around us.
+In the timbers of the bridges, in the trestlework and ties of
+railroads and in the piling of the wharves will be found portions
+showing rapid decay, while other portions are yet firm and in sound
+condition.</p>
+
+<p>Much more might be said in the explanation of this subject, but
+not wishing to extend the subject to an improper length, I will
+close. I would, however, say in conclusion that persons who have
+the opportunities and the inclination can verify the truth of a
+portion, at least, of what I have stated, in a simple manner and in
+a short time; for instance, by cutting two or three young fir or
+spruce saplings, say about six inches in diameter, mark them when
+cut, and also mark the stumps by driving pegs marked to correspond
+with the trees. Continue this monthly for the space of about one
+year, and note the difference in the wood, which should be left out
+and exposed to the weather until seasoned.</p>
+
+<p>C.W. HASKINS.</p>
+
+<hr>
+<p><a name="21"></a></p>
+
+<h2>RAISING FERNS FROM SPORES.</h2>
+
+<p class="ctr"><a href="./illustrations/15a.png"><img src=
+"./illustrations/15a_th.jpg" alt=
+" 1, PAN; 2, BELL GLASS; 3, SMALL POTS AND LABELS."></a></p>
+
+<p class="ctr">1, PAN; 2, BELL GLASS; 3, SMALL POTS AND LABELS.</p>
+
+<p>This plan, of which I give a sketch, has been in use by myself
+for many years, and most successfully. I have at various times
+given it to growers, but still I hear of difficulties. Procure a
+good sized bell-glass and an earthenware pan without any holes for
+drainage. Prepare a number of small pots, all filled for sowing,
+place them inside the pan, and fit the glass over them, so that it
+takes all in easily. Take these filled small pots out of the pan,
+place them on the ground, and well water them with boiling water to
+destroy all animal and vegetable life, and allow them to get
+perfectly cold; use a fine rose. Then taking each small pot
+separately, sow the spores on the surface and label them; do this
+with the whole number, and then place them in the pan under the
+bell-glass. This had better be done in a room, so that nothing
+foreign can grow inside. Having arranged the pots and placed the
+glass over them, and which should fit down upon the pan with ease,
+take a clean sponge, and tearing it up pack the pieces round the
+outside of the glass, and touching the inner side of the pan all
+round. Water this with cold water, so that the sponge is saturated.
+Do this whenever required, and always use water that has been
+boiled. At the end of six weeks or so the prothallus will perhaps
+appear, certainly in a week or two more; perhaps from unforeseen
+circumstances not for three months. Slowly these will begin to show
+themselves as young ferns, and most interesting it is to watch the
+results. As the ferns are gradually increasing in size pass a small
+piece of slate under the edge of the bell-glass to admit air, and
+do this by very careful degrees, allowing more and more air to
+reach them. Never water overhead until the seedlings are acclimated
+and have perfect form as ferns, and even then water at the edges of
+the pots. In due time carefully prick out, and the task so
+interesting to watch is performed.&mdash;<i>The Garden</i>.</p>
+
+<hr>
+<p><a name="22"></a></p>
+
+<h2>THE LIFE HISTORY OF VAUCHERIA.<a name="FNanchor_15"></a><a
+href="#Footnote_15"><sup>1</sup></a></h2>
+
+<h3>By A.H. BRECKENFELD.</h3>
+
+<p>Nearly a century ago, Vaucher, the celebrated Genevan botanist,
+described a fresh water filamentous alga which he named
+<i>Ectosperma geminata</i>, with a correctness that appears truly
+remarkable when the imperfect means of observation at his command
+are taken into consideration. His pupil, De Candolle, who afterward
+became so eminent a worker in the same field, when preparing his
+"Flora of France," in 1805, proposed the name of <i>Vaucheria</i>
+for the genus, in commemoration of the meritorious work of its
+first investigator. On March 12, 1826, Unger made the first
+recorded observation of the formation and liberation of the
+terminal or non-sexual spores of this plant. Hassall, the able
+English botanist, made it the subject of extended study while
+preparing his fine work entitled "A History of the British Fresh
+Water Alg&aelig;," published in 1845. He has given us a very
+graphic description of the phenomenon first observed by Unger. In
+1856 Pringsheim described the true sexual propagation by oospores,
+with such minuteness and accuracy that our knowledge of the plant
+can scarcely be said to have essentially increased since that
+time.</p>
+
+<p class="ctr"><a href="./illustrations/15b.png"><img src=
+"./illustrations/15b_th.jpg" alt=
+" GROWTH OF THE ALGA, VAUCHERIA, UNDER THE MICROSCOPE."></a></p>
+
+<p class="ctr">GROWTH OF THE ALGA, VAUCHERIA, UNDER THE
+MICROSCOPE.</p>
+
+<p><i>Vaucheria</i> has two or three rather doubtful marine species
+assigned to it by Harvey, but the fresh water forms are by far the
+more numerous, and it is to some of these I would call your
+attention for a few moments this evening. The plant grows in
+densely interwoven tufts, these being of a vivid green color, while
+the plant is in the actively vegetative condition, changing to a
+duller tint as it advances to maturity. Its habitat (with the
+exceptions above noted) is in freshwater&mdash;usually in ditches
+or slowly running streams. I have found it at pretty much all
+seasons of the year, in the stretch of boggy ground in the
+Presidio, bordering the road to Fort Point. The filaments attain a
+length of several inches when fully developed, and are of an
+average diameter of 1/250 (0.004) inch. They branch but sparingly,
+or not at all, and are characterized by consisting of a single long
+tube or cell, not divided by septa, as in the case of the great
+majority of the filamentous alg&aelig;. These tubular filaments are
+composed of a nearly transparent cellulose wall, including an inner
+layer thickly studded with bright green granules of chlorophyl.
+This inner layer is ordinarily not noticeable, but it retracts from
+the outer envelope when subjected to the action of certain
+reagents, or when immersed in a fluid differing in density from
+water, and it then becomes distinctly visible, as may be seen in
+the engraving (Fig. 1). The plant grows rapidly and is endowed with
+much vitality, for it resists changes of temperature to a
+remarkable degree. <i>Vaucheria</i> affords a choice hunting ground
+to the microscopist, for its tangled masses are the home of
+numberless infusoria, rotifers, and the minuter crustacea, while
+the filaments more advanced in age are usually thickly incrusted
+with diatoms. Here, too, is a favorite haunt of the beautiful
+zoophytes, <i>Hydra vividis</i> and <i>H. vulgaris</i>, whose
+delicate tentacles may be seen gracefully waving in nearly every
+gathering.</p>
+
+<h3>REPRODUCTION IN VAUCHERIA.</h3>
+
+<p>After the plant has attained a certain stage in its growth, if
+it be attentively watched, a marked change will be observed near
+the ends of the filaments. The chlorophyl appears to assume a
+darker hue, and the granules become more densely crowded. This
+appearance increases until the extremity of the tube appears almost
+swollen. Soon the densely congregated granules at the extreme end
+will be seen to separate from the endochrome of the filament, a
+clear space sometimes, but not always, marking the point of
+division. Here a septum or membrane appears, thus forming a cell
+whose length is about three or four times its width, and whose
+walls completely inclose the dark green mass of crowded granules
+(Fig. 1, b). These contents are now gradually forming themselves
+into the spore or "gonidium," as Carpenter calls it, in distinction
+from the true sexual spores, which he terms "oospores." At the
+extreme end of the filament (which is obtusely conical in shape)
+the chlorophyl grains retract from the old cellulose wall, leaving
+a very evident clear space. In a less noticeable degree, this is
+also the case in the other parts of the circumference of the cell,
+and, apparently, the granular contents have secreted a separate
+envelope entirely distinct from the parent filament. The grand
+climax is now rapidly approaching. The contents of the cell near
+its base are now so densely clustered as to appear nearly black
+(Fig. 1, c), while the upper half is of a much lighter hue and the
+separate granules are there easily distinguished, and, if very
+closely watched, show an almost imperceptible motion. The old
+cellulose wall shows signs of great tension, its conical extremity
+rounding out under the slowly increasing pressure from within.
+Suddenly it gives way at the apex. At the same instant, the
+inclosed gonidium (for it is now seen to be fully formed) acquires
+a rotary motion, at first slow, but gradually increasing until it
+has gained considerable velocity. Its upper portion is slowly
+twisted through the opening in the apex of the parent wall, the
+granular contents of the lower end flowing into the extruded
+portion in a manner reminding one of the flow of protoplasm in a
+living amoeba. The old cell wall seems to offer considerable
+resistance to the escape of the gonidium, for the latter, which
+displays remarkable elasticity, is pinched nearly in two while
+forcing its way through, assuming an hour glass shape when about
+half out. The rapid rotation of the spore continues during the
+process of emerging, and after about a minute it has fully freed
+itself (Fig 1, a). It immediately assumes the form of an ellipse or
+oval, and darts off with great speed, revolving on its major axis
+as it does so. Its contents are nearly all massed in the posterior
+half, the comparatively clear portion invariably pointing in
+advance. When it meets an obstacle, it partially flattens itself
+against it, then turns aside and spins off in a new direction. This
+erratic motion is continued for usually seven or eight minutes. The
+longest duration I have yet observed was a little over nine and
+one-half minutes. Hassall records a case where it continued for
+nineteen minutes. The time, however, varies greatly, as in some
+cases the motion ceases almost as soon as the spore is liberated,
+while in open water, unretarded by the cover glass or other
+obstacles, its movements have been seen to continue for over two
+hours.</p>
+
+<p>The motile force is imparted to the gonidium by dense rows of
+waving cilia with which it is completely surrounded. Owing to their
+rapid vibration, it is almost impossible to distinguish them while
+the spore is in active motion, but their effect is very plainly
+seen on adding colored pigment particles to the water. By
+subjecting the cilia to the action of iodine, their motion is
+arrested, they are stained brown, and become very plainly
+visible.</p>
+
+<p>After the gonidium comes gradually to a rest its cilia soon
+disappear, it becomes perfectly globular in shape, the inclosed
+granules distribute themselves evenly throughout its interior, and
+after a few hours it germinates by throwing out one, two, or
+sometimes three tubular prolongations, which become precisely like
+the parent filament (Fig 2).</p>
+
+<p>Eminent English authorities have advanced the theory that the
+ciliated gonidium of <i>Vaucheria</i> is in reality a densely
+crowded aggregation of biciliated zoospores, similar to those found
+in many other confervoid alg&aelig;. Although this has by no means
+been proved, yet I cannot help calling the attention of the members
+of this society to a fact which I think strongly bears out the said
+theory: While watching a gathering of <i>Vaucheria</i> one morning
+when the plant was in the gonidia-forming condition (which is
+usually assumed a few hours after daybreak), I observed one
+filament, near the end of which a septum had formed precisely as in
+the case of ordinary filaments about to develop a spore. But,
+instead of the terminal cell being filled with the usual densely
+crowded cluster of dark green granules constituting the rapidly
+forming spore, it contained hundreds of actively moving, nearly
+transparent zoospores, <i>and nothing else</i>. Not a single
+chlorophyl granule was to be seen. It is also to be noted as a
+significant fact, that the cellulose wall was <i>intact</i> at the
+apex, instead of showing the opening through which in ordinary
+cases the gonidium escapes. It would seem to be a reasonable
+inference, I think, based upon the theory above stated, that in
+this case the newly formed gonidium, unable to escape from its
+prison by reason of the abnormal strength of the cell wall, became
+after a while resolved into its component zoospores.</p>
+
+<h3>WONDERS OF REPRODUCTION.</h3>
+
+<p>I very much regret that my descriptive powers are not equal to
+conveying a sufficient idea of the intensely absorbing interest
+possessed by this wonderful process of spore formation. I shall
+never forget the bright sunny morning when for the first time I
+witnessed the entire process under the microscope, and for over
+four hours scarcely moved my eyes from the tube. To a thoughtful
+observer I doubt if there is anything in the whole range of
+microscopy to exceed this phenomenon in point of startling
+interest. No wonder that its first observer published his
+researches under the caption of "The Plant at the Moment of
+becoming an Animal."</p>
+
+<h3>FORMATION OF OTHER SPORES.</h3>
+
+<p>The process of spore formation just described, it will be seen,
+is entirely non-sexual, being simply a vegetative process,
+analogous to the budding of higher plants, and the fission of some
+of the lower plants and animals. <i>Vaucheria</i> has, however, a
+second and far higher mode of reproduction, viz., by means of
+fertilized cells, the true oospores, which, lying dormant as
+resting spores during the winter, are endowed with new life by the
+rejuvenating influences of spring. Their formation may be briefly
+described as follows:</p>
+
+<p>When <i>Vaucheria</i> has reached the proper stage in its life
+cycle, slight swellings appear here and there on the sides of the
+filament. Each of these slowly develops into a shape resembling a
+strongly curved horn. This becomes the organ termed the
+<i>antheridium</i>, from its analogy in function to the anther of
+flowering plants. While this is in process of growth, peculiar oval
+capsules or sporangia (usually 2 to 5 in number) are formed in
+close proximity to the antheridium. In some species both these
+organs are sessile on the main filament, in others they appear on a
+short pedicel (Figs. 3 and 4). The upper part of the antheridium
+becomes separated from the parent stem by a septum, and its
+contents are converted into ciliated motile antherozoids. The
+adjacent sporangia also become cut off by septa, and the investing
+membrane, when mature, opens: it a beak-like prolongation, thus
+permitting the inclosed densely congregated green granules to be
+penetrated by the antherozoids which swarm from the antheridium at
+the same time. After being thus fertilized the contents of the
+sporangium acquire a peculiar oily appearance, of a beautiful
+emerald color, an exceedingly tough but transparent envelope is
+secreted, and thus is constituted the fully developed oospore, the
+beginner of a new generation of the plant. After the production of
+this oospore the parent filament gradually loses its vitality and
+slowly decays.</p>
+
+<p>The spore being thus liberated, sinks to the bottom. Its
+brilliant hue has faded and changed to a reddish brown, but after a
+rest of about three months (according to Pringsheim, who seems to
+be the only one who has ever followed the process of oospore
+formation entirely through), the spore suddenly assumes its
+original vivid hue and germinates into a young
+<i>Vaucheria</i>.</p>
+
+<h3>CHARM OF MICROSCOPICAL STUDY.</h3>
+
+<p>This concludes the account of my very imperfect attempt to trace
+the life history of a lowly plant. Its study has been to me a
+source of ever increasing pleasure, and has again demonstrated how
+our favorite instrument reveals phenomena of most absorbing
+interest in directions where the unaided eye finds but little
+promise. In walking along the banks of the little stream, where,
+half concealed by more pretentious plants, our humble
+<i>Vaucheria</i> grows, the average passer by, if he notices it at
+all, sees but a tangled tuft of dark green "scum." Yet, when this
+is examined under the magic tube, a crystal cylinder, closely set
+with sparkling emeralds, is revealed. And although so transparent,
+so apparently simple in structure that it does not seem possible
+for even the finest details to escape our search, yet almost as we
+watch it mystic changes appear. We see the bright green granules,
+impelled by an unseen force, separate and rearrange themselves in
+new formations. Strange outgrowths from the parent filament appear.
+The strange power we call "life," doubly mysterious when manifested
+in an organism so simple as this, so open to our search, seems to
+challenge us to discover its secret, and, armed with our glittering
+lenses and our flashing stands of exquisite workmanship, we search
+intently, but in vain. And yet <i>not</i> in vain, for we are more
+than recompensed by the wondrous revelations beheld and the
+unalloyed pleasures enjoyed, through the study of even the
+unpretentious <i>Vaucheria</i>.</p>
+
+<p>The amplification of the objects in the engravings is about 80
+diameters.</p>
+
+<a name="Footnote_15"></a><a href="#FNanchor_15">[1]</a>
+
+<div class="note">Read before the San Francisco Microscopical
+Society, August 13, and furnished for publication in the
+<i>Press</i>.</div>
+
+<hr>
+<p><a name="2"></a></p>
+
+<h2>JAPANESE CAMPHOR&mdash;ITS PREPARATION, EXPERIMENTS, AND
+ANALYSIS OF THE CAMPHOR OIL.<a name="FNanchor_16"></a><a href=
+"#Footnote_16"><sup>1</sup></a></h2>
+
+<h3>By H. OISHI. (Communicated by Kakamatsa.)</h3>
+
+<p>LAURUS CAMPHORA, or "kusunoki," as it is called in Japan, grows
+mainly in those provinces in the islands Shikobu and Kinshin, which
+have the southern sea coast. It also grows abundantly in the
+province of Kishu.</p>
+
+<p>The amount of camphor varies according to the age of the tree.
+That of a hundred years old is tolerably rich in camphor. In order
+to extract the camphor, such a tree is selected; the trunk and
+large stems are cut into small pieces, and subjected to
+distillation with steam.</p>
+
+<p>An iron boiler of 3 feet in diameter is placed over a small
+furnace, the boiler being provided with an iron flange at the top.
+Over this flange a wooden tub is placed, which is somewhat narrowed
+at the top, being 1 foot 6 inches in the upper, and 2 feet 10
+inches in the lower diameter, and 4 feet in height. The tub has a
+false bottom for the passage of steam from the boiler beneath. The
+upper part of the tub is connected with a condensing apparatus by
+means of a wooden or bamboo pipe. The condenser is a flat
+rectangular wooden vessel, which is surrounded with another one
+containing cold water. Over the first is placed still another
+trough of the same dimensions, into which water is supplied to cool
+the vessel at the top. After the first trough has been filled with
+water, the latter flows into the next by means of a small pipe
+attached to it. In order to expose a large surface to the vapors,
+the condensing trough is fitted internally with a number of
+vertical partitions, which are open at alternate ends, so that the
+vapors may travel along the partitions in the trough from one end
+to the other. The boiler is filled with water, and 120 kilogrammes
+of chopped pieces of wood are introduced into the tub, which is
+then closed with a cover, cemented with clay, so as to make it
+air-tight. Firing is then begun; the steam passes into the tub, and
+thus carries the vapors of camphor and oil into the condenser, in
+which the camphor solidifies, and is mixed with the oil and
+condensed water. After twenty-four hours the charge is taken out
+from the tub, and new pieces of the wood are introduced, and
+distillation is conducted as before. The water in the boiler must
+be supplied from time to time. The exhausted wood is dried and used
+as fuel. The camphor and oil accumulated in the trough are taken
+out in five or ten days, and they are separated from each other by
+filtration. The yield of the camphor and oil varies greatly in
+different seasons. Thus much more solid camphor is obtained in
+winter than in summer, while the reverse is the case with the oil.
+In summer, from 120 kilogrammes of the wood 2.4 kilogrammes, or 2
+per cent. of the solid camphor are obtained in one day, while in
+winter, from the same amount of the wood, 3 kilogrammes, or 2.5 per
+cent., of camphor are obtainable at the same time.</p>
+
+<p>The amount of the oil obtained in ten days, <i>i.e</i>., from 10
+charges or 1,200 kilogrammes of the wood, in summer is about 18
+liters, while in winter it amounts only to 5-7 liters. The price of
+the solid camphor is at present about 1s. 1d. per kilo.</p>
+
+<p>The oil contains a considerable amount of camphor in solution,
+which is separated by a simple distillation and cooling. By this
+means about 20 per cent. of the camphor can be obtained from the
+oil. The author subjected the original oil to fractioned
+distillation, and examined different fractions separately. That
+part of the oil which distilled between 180&deg;-185&deg; O. was
+analyzed after repeated distillations. The following is the
+result:</p>
+
+<table summary="result">
+<tr>
+<th align="center">Found.</th>
+<th align="center"></th>
+<th align="center">Calculated as<br>
+C<sub>10</sub>H<sub>16</sub>O.</th>
+</tr>
+
+<tr>
+<td align="center">C = 78.87</td>
+<td align="center"></td>
+<td align="center">78.95</td>
+</tr>
+
+<tr>
+<td align="center">H = 10.73</td>
+<td align="center"></td>
+<td align="center">10.52</td>
+</tr>
+
+<tr>
+<td align="center">O = 10.40</td>
+<td align="center">(by difference)</td>
+<td align="center">10.52</td>
+</tr>
+</table>
+
+<p>The composition thus nearly agrees with that of the ordinary
+camphor.</p>
+
+<p>The fraction between 178&deg;-180&deg; C., after three
+distillations, gave the following analytical result:</p>
+
+<pre>
+C = 86.95
+H = 12.28
+    &mdash;&mdash;&mdash;&mdash;&mdash;
+    99.23
+</pre>
+
+<p>It appears from this result that the body is a hydrocarbon. The
+vapor density was then determined by V. Meyer's apparatus, and was
+found to be 5.7 (air=1). The molecular weight of the compound is
+therefore 5.7 &times; 14.42 &times; 2 = 164.4, which gives</p>
+
+<table summary="C_{12} H_{20}">
+<tr>
+<td>H = (164.4 &times; 12.28)/100 = 20.18</td>
+<td></td>
+</tr>
+
+<tr>
+<td></td>
+<td>or C<sub>12</sub>H<sub>20</sub></td>
+</tr>
+
+<tr>
+<td>C = (164.4 &times; 86.95)/100 = 11.81</td>
+<td></td>
+</tr>
+</table>
+
+<p>Hence it is a hydrocarbon of the terpene series, having the
+general formula C<sup>n</sup>H<sup>2n-4</sup>. From the above
+experiments it seems to be probable that the camphor oil is a
+complicated mixture, consisting of hydrocarbons of terpene series,
+oxy-hydrocarbons isomeric with camphor, and other oxidized
+hydrocarbons.</p>
+
+<h3><i>Application of the Camphor Oil</i>.</h3>
+
+<p>The distinguishing property of the camphor oil, that it
+dissolves many resins, and mixes with drying oils, finds its
+application for the preparation of varnish. The author has
+succeeded in preparing various varnishes with the camphor oil,
+mixed with different resins and oils. Lampblack was also prepared
+by the author, by subjecting the camphor oil to incomplete
+combustion. In this way from 100 c.c. of the oil, about 13 grammes
+of soot of a very good quality were obtained. Soot or lampblack is
+a very important material in Japan for making inks, paints, etc. If
+the manufacture of lampblack from the cheap camphor oil is
+conducted on a large scale, it would no doubt be profitable. The
+following is the report on the amount of the annual production of
+camphor in the province of Tosa up to 1880:</p>
+
+<pre>
+    Amount of Camphor produced.   Total Cost.
+
+1877.......... 504,000 kins.... 65,520 yen.
+1878.......... 519,000   " .... 72,660  "
+1879.......... 292,890   " .... 74,481  "
+1880.......... 192,837   " .... 58,302  "
+
+(1 yen = 2<i>s</i>. 9<i>d</i>.)
+(1 kin = 1-1/3lb.)
+</pre>
+
+<a name="Footnote_16"></a><a href="#FNanchor_16">[1]</a>
+
+<div class="note">From the Journal of the Society of Chemical
+Industry.</div>
+
+<hr>
+<p><a name="15"></a></p>
+
+<h2>THE SUNSHINE RECORDER.</h2>
+
+<p>McLeod's sunshine recorder consists of a camera fixed with its
+axis parallel to that of the earth, and with the lens northward.
+Opposite to the lens there is placed a round-bottomed flask,
+silvered inside. The solar rays reflected from this sphere pass
+through the lens, and act on the sensitive surface.</p>
+
+<p class="ctr"><a href="./illustrations/16a.png"><img src=
+"./illustrations/16a_th.jpg" alt=""></a></p>
+
+<p>The construction of the instrument is illustrated by the
+subjoined cut, A being a camera supported at an inclination of 56
+degrees with the horizon, and B the spherical flask silvered
+inside, while at D is placed the ferro-prussiate paper destined to
+receive the solar impression. The dotted line, C, may represent the
+direction of the central solar ray at one particular time, and it
+is easy to see how the sunlight reflected from the flask always
+passes through the lens. As the sun moves (apparently) in a circle
+round the flask, the image formed by the lens moves round on the
+sensitive paper, forming an arc of a circle.</p>
+
+<p>Although it is obvious that any sensitive surface might be used
+in the McLeod sunshine recorder, the inventor prefers at present to
+use the ordinary ferro-prussiate paper as employed by engineers for
+copying tracings, as this paper can be kept for a considerable
+length of time without change, and the blue image is fixed by mere
+washing in water; another advantage is the circumstance that a
+scale or set of datum lines can be readily printed on the paper
+from an engraved block, and if the printed papers be made to
+register properly in the camera, the records obtained will show at
+a glance the time at which sunshine commenced and ceased.</p>
+
+<p>Instead of specially silvering a flask inside, it will be found
+convenient to make use of one of the silvered globes which are sold
+as Christmas tree ornaments.</p>
+
+<p>The sensitive fluid for preparing the ferro-prussiate paper is
+made as follows: One part by weight of ferricyanide of potassium
+(red prussiate) is dissolved in eight parts of water, and one part
+of ammonia-citrate of iron is added. This last addition must be
+made in the dark-room. A smooth-faced paper is now floated on the
+liquid and allowed to dry.&mdash;<i>Photo. News.</i></p>
+
+<hr>
+<h2>BREAKING OF A WATER MAIN.</h2>
+
+<p>In Boston, Mass., recently, at a point where two iron bridges,
+with stone abutments, are being built over the Boston and Albany
+Railroad tracks at Brookline Avenue, the main water pipe, which
+partially supplies the city with water, had to be raised, and while
+in that position a large stone which was being raised slipped upon
+the pipe and broke it. Immediately a stream of water fifteen feet
+high spurted out. Before the water could be shut off it had made a
+breach thirty feet long in the main line of track, so that the
+entire four tracks, sleepers, and roadbed at that point were washed
+completely away.</p>
+
+<hr>
+<p>A catalogue, containing brief notices of many important
+scientific papers heretofore published in the SUPPLEMENT, may be
+had gratis at this office.</p>
+
+<hr>
+<h2>THE SCIENTIFIC AMERICAN SUPPLEMENT.</h2>
+
+<h3>PUBLISHED WEEKLY.</h3>
+
+<h3>Terms of Subscription, $5 a Year.</h3>
+
+<p>Sent by mail, postage prepaid, to subscribers in any part of the
+United States or Canada. Six dollars a year, sent, prepaid, to any
+foreign country.</p>
+
+<p>All the back numbers of THE SUPPLEMENT, from the commencement,
+January 1, 1876, can be had. Price, 10 cents each.</p>
+
+<p>All the back volumes of THE SUPPLEMENT can likewise be supplied.
+Two volumes are issued yearly. Price of each volume, $2.50,
+stitched in paper, or $3.50, bound in stiff covers.</p>
+
+<p>COMBINED RATES&mdash;One copy of SCIENTIFIC AMERICAN and one
+copy of SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid,
+$7.00.</p>
+
+<p>A liberal discount to booksellers, news agents, and
+canvassers.</p>
+
+<p><b>MUNN &amp; CO., Publishers,</b></p>
+
+<p><b>361 Broadway, New York, N.Y.</b></p>
+
+<hr>
+<h2><b>PATENTS.</b></h2>
+
+<p>In connection with the <b>Scientific American</b>, Messrs. MUNN
+&amp; Co. are Solicitors of American and Foreign Patents, have had
+39 years' experience, and now have the largest establishment in the
+world. Patents are obtained on the best terms.</p>
+
+<p>A special notice is made in the <b>Scientific American</b> of
+all Inventions patented through this Agency, with the name and
+residence of the Patentee. By the immense circulation thus given,
+public attention is directed to the merits of the new patent, and
+sales or introduction often easily effected.</p>
+
+<p>Any person who has made a new discovery or invention can
+ascertain, free of charge, whether a patent can probably be
+obtained, by writing to MUNN &amp; Co.</p>
+
+<p>We also send free our Hand Book about the Patent Laws, Patents,
+Caveats. Trade Marks, their costs, and how procured, with hints for
+procuring advances on inventions. Address</p>
+
+<p><b>MUNN &amp; CO., 361 Broadway, New York.</b></p>
+
+<p>Branch Office, cor. F and 7th Sts., Washington, D.C.</p>
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Scientific American Supplement, No.
+460, October 25, 1884, by Various
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+The Project Gutenberg EBook of Scientific American Supplement, No. 460,
+October 25, 1884, by Various
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Scientific American Supplement, No. 460, October 25, 1884
+
+Author: Various
+
+Release Date: March 28, 2004 [EBook #11734]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK  SCIENTIFIC AMERICAN 460 ***
+
+
+
+
+Produced by Don Kretz, Juliet Sutherland, Charles Franks and the DP Team
+
+
+
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 460
+
+
+
+
+NEW YORK, OCTOBER 25, 1884
+
+Scientific American Supplement. Vol. XVIII, No. 460.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+       *       *       *       *       *
+
+
+TABLE OF CONTENTS.
+
+I.    CHEMISTRY. ETC.--Wolpert's Method of Estimating the
+      Amount of Carbonic Acid in the Air.--7 Figures.
+
+      Japanese Camphor.--Its preparation, experiments, and analysis
+      of the camphor oil.--By H. OISHI.
+
+II.   ENGINEERING AND MECHANICS.--Links in the History of the
+      Locomotive.--With two engravings of the Rocket.
+
+      The Flow of Water through Turbines and Screw Propellers.--By
+      ARTHUR RIGG.--Experimental researches.--Impact on level
+      plate.--Impact and reaction in confined channels.--4 figures.
+
+      Improved Textile Machinery.--The Textile Exhibition at
+      Islington.--5 figures.
+
+      Endless Rope Haulage.--2 figures.
+
+III.  TECHNOLOGY.--A Reliable Water Filter.--With engraving.
+
+      Simple Devices for Distilling Water.--4 figures.
+
+      Improved Fire Damp Detecter.--With full description and engraving.
+
+      Camera Attachment for Paper Photo Negatives.--2 figures.
+
+      Instantaneous Photo Shutter.--1 figure.
+
+      Sulphurous Acid.--Easy method of preparation for photographic
+      purposes.
+
+IV.   PHYSICS. ELECTRICITY, ETC.--Steps toward a Kinetic
+      Theory of Matter.--Address by Sir Wm. THOMSON at the Montreal
+      meeting of the British Association.
+
+      Application of Electricity to Tramways.--By M. HOLROYD
+      SMITH.--7 figures.
+
+      The Sunshine Recorder.--1 figure.
+
+V.    ARCHITECTURE AND ART.--The National Monument at Rome.--With
+      full page engraving.
+
+      On the Evolution of Forms of Art.--From a paper by Prof.
+      JACOBSTHAL.--Plant Forms the archetypes of cashmere
+      patterns.--Ornamental representations of plants of two
+      kinds.--Architectural forms of different ages.--20 figures.
+
+VI.   NATURAL HISTORY.--The Latest Knowledge about Gapes.--How
+      to keep poultry free from them.
+
+      The Voyage of the Vettor Pisani.--Shark fishing In the Gulf
+      of Panama.--Capture of Rhinodon typicus, the largest fish in
+      existence.
+
+VII.  HORTICULTURE, ETC.--The Proper Time for Cutting Timber.
+
+      Raising Ferns from Spores.--1 figure.
+
+      The Life History of Vaucheria.--Growth of alga vaucheria
+      under the microscope.--4 figures.
+
+VIII. MISCELLANEOUS.--Fires in London and New York.
+
+      The Greely Arctic Expedition.--With engraving.
+
+      The Nile Expedition.--1 figure.
+
+       *       *       *       *       *
+
+
+
+
+LINKS IN THE HISTORY OF THE LOCOMOTIVE.
+
+
+It is, perhaps, more difficult to write accurate history than anything
+else, and this is true not only of nations, kings, politicians, or wars,
+but of events and things witnessed or called into existence in every-day
+life. In _The Engineer_ for September 17, 1880, we did our best to place a
+true statement of the facts concerning the Rocket before our readers. In
+many respects this was the most remarkable steam engine ever built, and
+about it there ought to be no difficulty, one would imagine, in arriving at
+the truth. It was for a considerable period the cynosure of all eyes.
+Engineers all over the world were interested in its performance. Drawings
+were made of it; accounts were written of it, descriptions of it abounded.
+Little more than half a century has elapsed since it startled the world by
+its performance at Rainhill, and yet it is not too much to say that the
+truth--the whole truth, that is to say--can never now be written. We are,
+however, able to put some facts before our readers now which have never
+before been published, which are sufficiently startling, and while
+supplying a missing link in the history of the locomotive, go far to show
+that much that has hitherto been held to be true is not true at all.
+
+When the Liverpool and Manchester Railway was opened on the 15th of
+September, 1830, among those present was James Nasmyth, subsequently the
+inventor of the steam hammer. Mr. Nasmyth was a good freehand draughtsman,
+and he sketched the Rocket as it stood on the line. The sketch is still in
+existence. Mr. Nasmyth has placed this sketch at our disposal, thus earning
+the gratitude of our readers, and we have reproduced as nearly as possible,
+but to a somewhat enlarged scale, this invaluable link in the history of
+the locomotive. Mr. Nasmyth writes concerning it, July 26, 1884: "This
+slight and hasty sketch of the Rocket was made the day before the opening
+of the Manchester and Liverpool Railway, September 12, 1830. I availed
+myself of the opportunity of a short pause in the experimental runs with
+the Rocket, of three or four miles between Liverpool and Rainhill, George
+Stephenson acting as engine driver and his son Robert as stoker. The
+limited time I had for making my sketch prevented me from making a more
+elaborate one, but such as it is, all the important and characteristic
+details are given; but the pencil lines, after the lapse of fifty-four
+years, have become somewhat indistinct." The pencil drawing, more than
+fifty years old, has become so faint that its reproduction has become a
+difficult task. Enough remains, however, to show very clearly what manner
+of engine this Rocket was. For the sake of comparison we reproduce an
+engraving of the Rocket of 1829. A glance will show that an astonishing
+transformation had taken place in the eleven months which had elapsed
+between the Rainhill trials and the opening of the Liverpool and Manchester
+Railway. We may indicate a few of the alterations. In 1829 the cylinders
+were set at a steep angle; in 1830 they were nearly horizontal. In 1829 the
+driving wheels were of wood; in 1830 they were of cast iron. In 1829 there
+was no smoke-box proper, and a towering chimney; in 1830 there was a
+smoke-box and a comparatively short chimney. In 1829 a cask and a truck
+constituted the tender; in 1830 there was a neatly designed tender, not
+very different in style from that still in use on the Great Western broad
+gauge. All these things may perhaps be termed concomitants, or changes in
+detail. But there is a radical difference yet to be considered. In 1829 the
+fire-box was a kind of separate chamber tacked on to the back of the barrel
+of the boiler, and communicating with it by three tubes; one on each side
+united the water spaces, and one at the top the steam spaces. In 1830 all
+this had disappeared, and we find in Mr. Nasmyth's sketch a regular
+fire-box, such as is used to this moment. In one word, the Rocket of 1829
+is different from the Rocket of 1830 in almost every conceivable respect;
+and we are driven perforce to the conclusion that the Rocket of 1829
+_never worked at all on the Liverpool and Manchester Railway; the engine of
+1830 was an entirely new engine_. We see no possible way of escaping from
+this conclusion. The most that can be said against it is that the engine
+underwent many alterations. The alterations must, however, have been so
+numerous that they were tantamount to the construction of a new engine. It
+is difficult, indeed, to see what part of the old engine could exist in the
+new one; some plates of the boiler shell might, perhaps, have been
+retained, but we doubt it. It may, perhaps, disturb some hitherto well
+rooted beliefs to say so, but it seems to us indisputable that the Rocket
+of 1829 and 1830 were totally different engines.
+
+[Illustration: FIG. 1. THE ROCKET, 1829. THE ROCKET, 1830.]
+
+Our engraving, Fig. 1, is copied from a drawing made by Mr. Phipps,
+M.I.C.E., who was employed by Messrs. Stephenson to compile a drawing of
+the Rocket from such drawings and documents as could be found. This
+gentleman had made the original drawings of the Rocket of 1829, under
+Messrs. G. & R. Stephenson's direction. Mr. Phipps is quite silent about
+the history of the engine during the eleven months between the Rainhill
+trials and the opening of the railway. In this respect he is like every one
+else. This period is a perfect blank. It is assumed that from Rainhill the
+engine went back to Messrs. Stephenson's works; but there is nothing on the
+subject in print, so far as we are aware. Mr. G.R. Stephenson lent us in
+1880 a working model of the Rocket. An engraving of this will be found in
+_The Engineer_ for September 17, 1880. The difference between it and the
+engraving below, prepared from Mr. Phipps' drawing, is, it will be seen,
+very small--one of proportions more than anything else. Mr. Stephenson says
+of his model: "I can say that it is a very fair representation of what the
+engine was before she was altered." Hitherto it has always been taken for
+granted that the alteration consisted mainly in reducing the angle at which
+the cylinders were set. The Nasmyth drawing alters the whole aspect of the
+question, and we are now left to speculate as to what became of the
+original Rocket. We are told that after "it" left the railway it was
+employed by Lord Dundonald to supply steam to a rotary engine; then it
+propelled a steamboat; next it drove small machinery in a shop in
+Manchester; then it was employed in a brickyard; eventually it was
+purchased as a curiosity by Mr. Thomson, of Kirkhouse, near Carlisle, who
+sent it to Messrs. Stephenson to take care of. With them it remained for
+years. Then Messrs. Stephenson put it into something like its original
+shape, and it went to South Kensington Museum, where "it" is now. The
+question is, What engine is this? Was it the Rocket of 1829 or the Rocket
+of 1830, or neither? It could not be the last, as will be understood from
+Mr. Nasmyth's drawing; if we bear in mind that the so-called fire-box on
+the South Kensington engine is only a sham made of thin sheet iron without
+water space, while the fire-box shown in Mr. Nasmyth's engine is an
+integral part of the whole, which could not have been cut off. That is to
+say, Messrs. Stephenson, in getting the engine put in order for the Patent
+Office Museum, certainly did not cut off the fire-box shown in Mr.
+Nasmyth's sketch, and replace it with the sham box now on the boiler. If
+our readers will turn to our impression for the 30th of June, 1876, they
+will find a very accurate engraving of the South Kensington engine, which
+they can compare with Mr. Nasmyth's sketch, and not fail to perceive that
+the differences are radical.
+
+In "Wood on Railroads," second edition, 1832, page 377, we are told that
+"after those experiments"--the Rainhill trials--"were concluded, the
+Novelty underwent considerable alterations;" and on page 399, "Mr.
+Stephenson had also improved the working of the Rocket engine, and by
+applying the steam more powerfully in the chimney to increase the draught,
+was enabled to raise a much greater quantity of steam than before." Nothing
+is said as to where the new experiments took place, nor their precise date.
+But it seems that the Meteor and the Arrow--Stephenson engines--were tried
+at the same time; and this is really the only hint Wood gives as to what
+was done to the Rocket between the 6th of October, 1829, and the 15th of
+September, 1830.
+
+There are men still alive who no doubt could clear up the question at
+issue, and it is much to be hoped that they will do so. As the matter now
+stands, it will be seen that we do not so much question that the Rocket in
+South Kensington Museum is, in part perhaps, the original Rocket of
+Rainhill celebrity, as that it ever ran in regular service on the Liverpool
+and Manchester Railway. Yet, if not, then we may ask, what became of the
+Rocket of 1830? It is not at all improbable that the first Rocket was cast
+on one side, until it was bought by Lord Dundonald, and that its history is
+set out with fair accuracy above. But the Rocket of the Manchester and
+Liverpool Railway is hardly less worthy of attention than its immediate
+predecessor, and concerning it information is needed. Any scrap of
+information, however apparently trifling, that can be thrown on this
+subject by our readers will be highly valued, and given an appropriate
+place in our pages.--_The Engineer_.
+
+       *       *       *       *       *
+
+The largest grain elevator in the world, says the _Nashville American_, is
+that just constructed at Newport News under the auspices of the Chesapeake
+& Ohio Railway Co. It is 90 ft. wide, 386 ft. long, and about 164 ft. high,
+with engine and boiler rooms 40 x 100 ft. and 40 ft. high. In its
+construction there were used about 3,000 piles, 100,000 ft. of white-oak
+timber, 82,000 cu. ft. of stone, 800,000 brick, 6,000,000 ft. of pine and
+spruce lumber, 4,500 kegs of nails, 6 large boilers, 2 large engines, 200
+tons of machinery, 20 large hopper-scales, and 17,200 ft. of rubber belts,
+from 8 to 48 in. wide and 50 to 1,700 ft. long; in addition, there were
+8,000 elevator buckets, and other material. The storage capacity is
+1,600,000 bushels, with a receiving capacity of 30,000, and a shipping
+capacity of 20,000 bushels per hour.
+
+       *       *       *       *       *
+
+
+
+
+THE FLOW OF WATER THROUGH TURBINES AND SCREW PROPELLERS.
+
+[Footnote: Paper read before the British Association at Montreal.]
+
+By Mr. ARTHUR RIGG, C.E.
+
+
+Literature relating to turbines probably stands unrivaled among all that
+concerns questions of hydraulic engineering, not so much in its voluminous
+character as in the extent to which purely theoretical writers have ignored
+facts, or practical writers have relied upon empirical rules rather than
+upon any sound theory. In relation to this view, it may suffice to note
+that theoretical deductions have frequently been based upon a
+generalization that "streams of water must enter the buckets of a turbine
+without shock, and leave them without velocity." Both these assumed
+conditions are misleading, and it is now well known that in every good
+turbine both are carefully disobeyed. So-called practical writers, as a
+rule, fail to give much useful information, and their task seems rather in
+praise of one description of turbine above another. But generally, it is of
+no consequence whatever how a stream of water may be led through the
+buckets of any form of turbine, so long as its velocity gradually becomes
+reduced to the smallest amount that will carry it freely clear of the
+machine.
+
+The character of theoretical information imparted by some _Chicago Journal
+of Commerce_, dated 20th February, 1884. There we are informed that "the
+height of the fall is one of the most important considerations, as the same
+stream of water will furnish five times the horse power at ten ft. that it
+will at five ft. fall." By general consent twice two are four, but it has
+been reserved for this imaginative writer to make the useful discovery that
+sometimes twice two are ten. Not until after the translation of Captain
+Morris' work on turbines by Mr. E. Morris in 1844, was attention in America
+directed to the advantages which these motors possessed over the gravity
+wheels then in use. A duty of 75 per cent. was then obtained, and a further
+study of the subject by a most acute and practical engineer, Mr. Boyden,
+led to various improvements upon Mr. Fauneyron's model, by which his
+experiments indicated the high duty of 88 per cent. The most conspicuous
+addition made by Mr. Boyden was the diffuser. The ingenious contrivance had
+the effect of transforming part of whatever velocity remained in the stream
+after passing out of a turbine into an atmospheric pressure, by which the
+corresponding lost head became effective, and added about 3 per cent. to
+the duty obtained. It may be worth noticing that, by an accidental
+application of these principles to some inward flow turbines, there is
+obtained most, if not all, of whatever advantage they are supposed to
+possess, but oddly enough this genuine advantage is never mentioned by any
+of the writers who are interested in their introduction or sale. The
+well-known experiments of Mr. James B. Francis in 1857, and his elaborate
+report, gave to hydraulic engineers a vast store of useful data, and since
+that period much progress has been made in the construction of turbines,
+and literature on the subject has become very complete.
+
+In the limits of a short paper it is impossible to do justice to more than
+one aspect of the considerations relating to turbines, and it is now
+proposed to bring before the Mechanical Section of the British Association
+some conclusions drawn from the behavior of jets of water discharged under
+pressure, more particularly in the hope that, as water power is extremely
+abundant in Canada, any remarks relating to the subject may not fail to
+prove interesting.
+
+Between the action of turbines and that of screw propellers exists an exact
+parallelism, although in one case water imparts motion to the buckets of a
+turbine, while in the other case blades of a screw give spiral movement to
+a column of water driven aft from the vessel it propels forward. Turbines
+have been driven sometimes by impact alone, sometimes by reaction above,
+though generally by a combination of impact and reaction, and it is by the
+last named system that the best results are now known to be obtained.
+
+The ordinary paddles of a steamer impel a mass of water horizontally
+backward by impact alone, but screw propellers use reaction somewhat
+disguised, and only to a limited extent. The full use and advantages of
+reaction for screw propellers were not generally known until after the
+publication of papers by the present writer in the "Proceedings" of the
+Institution of Naval Architects for 1867 and 1868, and more fully in the
+"Transactions" of the Society of Engineers for 1868. Since that time, by
+the author of these investigations then described, by the English
+Admiralty, and by private firms, further experiments have been carried out,
+some on a considerable scale, and all corroborative of the results
+published in 1868. But nothing further has been done in utilizing these
+discoveries until the recent exigencies of modern naval warfare have led
+foreign nations to place a high value upon speed. Some makers of torpedo
+boats have thus been induced to slacken the trammels of an older theory and
+to apply a somewhat incomplete form of the author's reaction propeller for
+gaining some portion of the notable performance of these hornets of the
+deep. Just as in turbines a combination of impact and reaction produces the
+maximum practical result, so in screw propellers does a corresponding gain
+accompany the same construction.
+
+[Illustration: FIG. 1.]
+
+[Illustration: FIG. 2.]
+
+_Turbines_.--While studying those effects produced by jets of water
+impinging upon plain or concave surfaces corresponding to buckets of
+turbines, it simplifies matters to separate these results due to impact
+from others due to reaction. And it will be well at the outset to draw a
+distinction between the nature of these two pressures, and to remind
+ourselves of the laws which lie at the root and govern the whole question
+under present consideration. Water obeys the laws of gravity, exactly like
+every other body; and the velocity with which any quantity may be falling
+is an expression of the full amount of work it contains. By a sufficiently
+accurate practical rule this velocity is eight times the square root of the
+head or vertical column measured in feet. Velocity per second = 8 sqrt
+(head in feet), therefore, for a head of 100 ft. as an example, V = 8 sqrt
+(100) = 80 ft. per second. The graphic method of showing velocities or
+pressures has many advantages, and is used in all the following diagrams.
+Beginning with purely theoretical considerations, we must first recollect
+that there is no such thing as absolute motion. All movements are relative
+to something else, and what we have to do with a stream of water in a
+turbine is to reduce its velocity relatively to the earth, quite a
+different thing to its velocity in relation to the turbine; for while the
+one may be zero, the other may be anything we please. ABCD in Fig. 1
+represents a parallelogram of velocities, wherein AC gives the direction of
+a jet of water starting at A, and arriving at C at the end of one second or
+any other division of time. At a scale of 1/40 in. to 1 ft., AC represents
+80 ft., the fall due to 100 ft. head, or at a scale of 1 in. to 1 ft., AC
+gives 2 ft., or the distance traveled by the same stream in 1/40 of a
+second. The velocity AC may be resolved into two others, namely, AB and AD,
+or BC, which are found to be 69.28 ft. and 40 ft. respectively, when the
+angle BAC--generally called _x_ in treatises on turbines--is 30 deg. If,
+however, AC is taken at 2 ft., then A B will be found = 20.78 in., and BC =
+12 in. for a time of 1/40 or 0.025 of a second. Supposing now a flat plate,
+BC = 12 in. wide move from DA to CB during 0.025 second, it will be readily
+seen that a drop of water starting from A will have arrived at C in 0.025
+second, having been flowing along the surface BC from B to C without either
+friction or loss of velocity. If now, instead of a straight plate, BC, we
+substitute one having a concave surface, such as BK in Fig. 2, it will be
+found necessary to move it from A to L in 0.025 second, in order to allow a
+stream to arrive at C, that is K, without, in transit, friction or loss of
+velocity. This concave surface may represent one bucket of a turbine.
+Supposing now a resistance to be applied to that it can only move from A to
+B instead of to L. Then, as we have already resolved the velocity A C into
+AB and BC, so far as the former (AB) is concerned, no alteration occurs
+whether BK be straight or curved. But the other portion, BC, pressing
+vertically against the concave surface, BK, becomes gradually diminished in
+its velocity in relation to the earth, and produces and effect known as
+"reaction." A combined operation of impact and reaction occurs by further
+diminishing the distance which the bucket is allowed to travel, as, for
+examples, to EF. Here the jet is impelled against the lower edge of the
+bucket, B, and gives a pressure by its impact; then following the curve BK,
+with a diminishing velocity, it is finally discharged at K, retaining only
+sufficient movement to carry the water clear out of the machine. Thus far
+we have considered the movement of jets and buckets along AB as straight
+lines, but this can only occur, so far as buckets are concerned, when their
+radius in infinite. In practice these latter movements are always curves of
+more or less complicated form, which effect a considerable modification in
+the forms of buckets, etc., but not in the general principles, and it is
+the duty of the designer of any form of turbine to give this consideration
+its due importance. Having thus cleared away any ambiguity from the terms
+"impact," and "reaction," and shown how they can act independently or
+together, we shall be able to follow the course and behavior of streams in
+a turbine, and by treating their effects as arising from two separate
+causes, we shall be able to regard the problem without that inevitable
+confusion which arises when they are considered as acting conjointly.
+Turbines, though driven by vast volumes of water, are in reality impelled
+by countless isolated jets, or streams, all acting together, and a clear
+understanding of the behavior of any one of these facilitates and concludes
+a solution of the whole problem.
+
+_Experimental researches_.--All experiments referred to in this paper were
+made by jets of water under an actual vertical head of 45 ft., but as the
+supply came through a considerable length of 1/2 in. bore lead piping, and
+many bends, a large and constant loss occurred through friction and bends,
+so that the actual working head was only known by measuring the velocity of
+discharge. This was easily done by allowing all the water to flow into a
+tank of known capacity. The stop cock had a clear circular passage through
+it, and two different jets were used. One oblong measured 0.5 in. by 0.15
+in., giving an area of 0.075 square inch. The other jet was circular, and
+just so much larger than 1/4 in. to be 0.05 of a square inch area, and the
+stream flowed with a velocity of 40 ft. per second, corresponding to a head
+of 25 ft. Either nozzle could be attached to the same universal joint, and
+directed at any desired inclination upon the horizontal surface of a
+special well-adjusted compound weighing machine, or into various bent tubes
+and other attachments, so that all pressures, whether vertical or
+horizontal, could be accurately ascertained and reduced to the unit, which
+was the quarter of an ounce. The vertical component _p_ of any pressure P
+may be ascertained by the formula--
+
+    _p_ = P sin alpha,
+
+where alpha is the angle made by a jet against a surface; and in order to
+test the accuracy of the simple machinery employed for these researches,
+the oblong jet which gave 71 unit when impinging vertically upon a circular
+plate, was directed at 60 deg. and 45 deg. thereon, with results shown in
+Table I., and these, it will be observed, are sufficiently close to theory
+to warrant reliance being placed on data obtained from the simple weighing
+machinery used in the experiment.
+
+                 _Table I.--Impact on Level Plate._
+--------------+--------------------+----------+----------+----------
+              | Inclination of jet |          |          |
+  Distance.   | to the horizonal.  |  90 deg. |  60 deg. |  45 deg.
+--------------+--------------------+----------+----------+----------
+              |                    | Pressure | Pressure | Pressure
+              |                    |          |          |
+            / |  Experiment    \   |        / |   61.00  |   49.00
+ 11/2 in.    <  |                 >  | 71.00 <  |          |
+            \ |  Theory        /   |        \ |   61.48  |   50.10
+              |                    |          |          |
+              |                    |          |          |
+            / |  Experiment    \   |        / |   55.00  |   45.00
+ 1 in.     <  |                 >  | 63.00 <  |          |
+            \ |  Theory        /   |        \ |   54.00  |   45.00
+              |                    |          |          |
+--------------+--------------------+----------+----------+----------
+             In each case the unit of pressure is 1/4 oz.
+
+In the first trial there was a distance of 11/2 in. between the jet and point
+of its contact with the plate, while in the second trial this space was
+diminished to 1/2 in. It will be noticed that as this distance increases we
+have augmented pressures, and these are not due, as might be supposed, to
+increase of head, which is practically nothing, but they are due to the
+recoil of a portion of the stream, which occurs increasingly as it becomes
+more and more broken up. These alterations in pressure can only be
+eliminated when care is taken to measure that only due to impact, without
+at the same time adding the effect of an imperfect reaction. Any stream
+that can run off at all points from a smooth surface gives the minimum of
+pressure thereon, for then the least resistance is offered to the
+destruction of the vertical element of its velocity, but this freedom
+becomes lost when a stream is diverted into a confined channel. As pressure
+is an indication and measure of lost velocity, we may then reasonably look
+for greater pressure on the scale when a stream is confined after impact
+than when it discharges freely in every direction. Experimentally this is
+shown to be the case, for when the same oblong jet, discharged under the
+same conditions, impinged vertically upon a smooth plate, and gave a
+pressure of 71 units, gave 87 units when discharged into a confined
+right-angled channel. This result emphasizes the necessity for confining
+streams of water whenever it is desired to receive the greatest pressure by
+arresting their velocity. Such streams will always endeavor to escape in
+the directions of least resistance, and, therefore, in a turbine means
+should be provided to prevent any lateral deviation of the streams while
+passing through their buckets. So with screw propellers the great mass of
+surrounding water may be regarded as acting like a channel with elastic
+sides, which permits the area enlarging as the velocity of a current
+passing diminishes. The experiments thus far described have been made with
+jets of an oblong shape, and they give results differing in some degree
+from those obtained with circular jets. Yet as the general conclusions from
+both are found the same, it will avoid unnecessary prolixity by using the
+data from experiments made with a circular jet of 0.05 square inch area,
+discharging a stream at the rate of 40 ft. per second. This amounts to 52
+lb. of water per minute with an available head of 25 ft., or 1,300
+foot-pounds per minute. The tubes which received and directed the course of
+this jet were generally of lead, having a perfectly smooth internal
+surface, for it was found that with a rougher surface the flow of water is
+retarded, and changes occur in the data obtained. Any stream having its
+course changed presses against the body causing such change, this pressure
+increasing in proportion to the angle through which the change is made, and
+also according to the radius of a curve around which it flows. This fact
+has long been known to hydraulic engineers, and formulae exist by which such
+pressures can be determined; nevertheless, it will be useful to study these
+relations from a somewhat different point of view than has been hitherto
+adopted, more particularly as they bear upon the construction of screw
+propellers and turbines; and by directing the stream, AB, Fig. 3,
+vertically into a tube 3/8 in. internal diameter and bent so as to turn the
+jet horizontally, and placing the whole arrangement upon a compound
+weighing machine, it is easy to ascertain the downward pressure, AB, due to
+impact, and the horizontal pressures, CB, due to reaction. In theoretical
+investigations it may be convenient to assume both these pressures exactly
+equal, and this has been done in the paper "On Screw Propellers" already
+referred to; but this brings in an error of no importance so far as general
+principles are involved, but one which destroys much of the value such
+researches might, otherwise possess for those who are engaged in the
+practical construction of screw propellers or turbines. The downward impact
+pressure, AB, is always somewhat greater than the horizontal reaction, BC,
+and any proportions between these two can only be accurately ascertained by
+trials. In these particular experiments the jet of water flowed 40 ft. per
+second through an orifice of 0.05 square inch area, and in every case its
+course was bent to a right angle. The pressures for impact and reaction
+were weighed coincidently, with results given by columns 1 and 2, Table II.
+
+[Illustration: FIG. 3]
+
+[Illustration: FIG. 4]
+
+_Table II.--Impact and Reaction in Confined Channels._
+
+-----------------------------+-------+---------+----------+-------
+Number of column.            |   1   |    2    |    3     |   4
+-----------------------------+-------+---------+----------+-------
+Description of experiments.  |Impact.|Reaction.|Resultant.| Angles
+                             |       |         |          |  ABS.
+-----------------------------+-------+---------+----------+-------
+Smooth London tube, 13/4 in.   |  71   |   62    |  94.25   |   49 deg.
+  mean radius.               |       |         |          |
+                             |       |         |          |
+Rough wrought iron tube,     |  78   |   52    |  98.75   |  56.5 deg.
+  13/4 in.                     |       |         |          |
+                             |       |         |          |
+Smooth leaden tube bent to a |  71   |   40    |  81.5    |   60
+  sharp right angle.         |       |         |          |
+-----------------------------+-------+---------+----------+------
+
+The third column is obtained by constructing a parallelogram of forces,
+where impact and reaction form the measures of opposing sides, and it
+furnishes the resultant due to both forces. The fourth column gives the
+inclination ABS, at which the line of impact must incline toward a plane
+surface RS, Fig. 3, so as to produce this maximum resultant perpendicularly
+upon it; as the resultant given in column 3 indicates the full practical
+effect of impact and reaction. When a stream has its direction changed to
+one at right angles to its original course, and as such a changed direction
+is all that can be hoped for by ordinary screw propellers, the figures in
+column 3 should bear some relationship to such cases. Therefore, it becomes
+an inquiry of some interest as to what angle of impact has been found best
+in those screw propellers which have given the best results in practical
+work. Taking one of the most improved propellers made by the late Mr.
+Robert Griffiths, its blades do not conform to the lines of a true screw,
+but it is an oblique paddle, where the acting portions of its blades were
+set at 48 deg. to the keel of the ship or 42 deg. to the plane of rotation.
+Again, taking a screw tug boat on the river Thames, with blades of a
+totally different form to those used by Mr. Griffiths, we still find them
+set at the same angle, namely, 48 deg. to the keel or 42 deg. to the plane
+of rotation. An examination of other screws tends only to confirm these
+figures, and they justify the conclusion that the inclinations of blades
+found out by practice ought to be arrived at, or at any rate approached, by
+any sound and reliable theory; and that blades of whatever form must not
+transgress far from this inclination if they are to develop any
+considerable efficiency. Indeed, many favorable results obtained by
+propellers are not due to their peculiarities, but only to the fact that
+they have been made with an inclination of blade not far from 42 deg. to
+the plan of rotation. Referring to column 4, and accepting the case of
+water flowing through a smooth tube as analogous to that of a current
+flowing within a large body of water, it appears that the inclination
+necessary to give the highest resultant pressure is an angle of 49 deg.,
+and this corresponds closely enough with the angle which practical
+constructors of screw propellers have found to give the best results.
+Until, therefore, we can deal with currents after they have been
+discharged from the blades of a propeller, it seems unlikely that anything
+can be done by alterations in the pitch of a propeller. So far as concerns
+theory, the older turbines were restricted to such imperfect results of
+impact and reaction as might be obtained by turning a stream at right
+angles to its original course; and the more scientific of modern turbine
+constructors may fairly claim credit for an innovation by which practice
+gave better results than theory seemed to warrant; and the consideration of
+this aspect of the question will form the concluding subject of the present
+paper. Referring again to Fig. 3, when a current passes round such a curve
+as the quadrant of a circle, its horizontal reaction appears as a pressure
+along _c_ B, which is the result of the natural integration of all the
+horizontal components of pressures, all of which act perpendicularly to
+each element of the concave surface along which the current flows. If, now,
+we add another quadrant of a circle to the curve, and so turn the stream
+through two right angles, or 180 deg., as shown by Fig. 4, then such a
+complete reversal of the original direction represents the carrying of it
+back again to the highest point; it means the entire destruction of its
+velocity, and it gives the maximum pressure obtainable from a jet of water
+impinging upon a surface of any form whatsoever. The reaction noticed in
+Fig. 3 as acting along _c_ B is now confronted by an impact of the now
+horizontal stream as it is turned round the second 90 deg. of curvature,
+and reacts also vertically downward. It would almost seem as if the first
+reaction from B to F should be exactly neutralized by the second impact
+from F to D. But such is not the case, as experiment shows an excess of the
+second impact over the first reaction amounting to six units, and shows
+also that the behavior of the stream through its second quadrant is
+precisely similar in kind to the first, only less in degree. Also the
+impact takes place vertically in one case and horizontally in the other.
+The total downward pressure given by the stream when turned 180 deg. is
+found by experiment thus: Total impact and reaction from 180 deg. change in
+direction of current = 132 units; and by deducting the impact 71 units, as
+previously measured, the new reaction corresponds with an increase of 61
+units above the first impact. It also shows an increase of 37.75 units
+above the greatest resultant obtained by the same stream turned through 90
+deg. only. Therefore, in designing a screw propeller or turbine, it would
+seem from these experiments desirable to aim at changing the direction of
+the stream, so far as possible, into one at 180 deg. to its original
+course, and it is by carrying out this view, so far as the necessities of
+construction will permit, that the scientifically designed modern turbine
+has attained to that prominence which it holds at present over all
+hydraulic motors. Much more might be written to extend and amplify the
+conclusions that can be drawn from the experiments described in the present
+paper, and from many others made by the writer, but the exigencies of time
+and your patience alike preclude further consideration of this interesting
+and important subject.
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED TEXTILE MACHINERY.
+
+
+[Illustration: THE TEXTILE EXHIBITION, ISLINGTON.]
+
+In the recent textile exhibition at Islington, one of the most extensive
+exhibits was that, of Messrs. James Farmer and Sons, of Salford. The
+exhibit consists of a Universal calender, drying machines, patent creasing,
+measuring, and marking machines, and apparatus for bleaching, washing,
+chloring, scouring, soaping, dunging, and dyeing woven fabrics. The purpose
+of the Universal calender is, says the _Engineer_, to enable limited
+quantities of goods to be finished in various ways without requiring
+different machines. The machine consists of suitable framing, to which is
+attached all the requisite stave rails, batching apparatus, compound
+levers, top and bottom adjusting screws, and level setting down gear, also
+Stanley roller with all its adjustments. It is furthermore supplied with
+chasing arrangement and four bowls; the bottom one is of cast iron, with
+wrought iron center; the next is of paper or cotton; the third of chilled
+iron fitted for heating by steam or gas, and the top of paper or cotton. By
+this machine are given such finishes as are known as "chasing finish" when
+the thready surface is wanted; "frictioning," or what is termed "glazing
+finish," "swigging finish," and "embossing finish;" the later is done by
+substituting a steel or copper engraved roller in place of the friction
+bowl. This machine is also made to I produce the "Moire luster" finish. The
+drying machine consists of nineteen cylinders, arranged with stave rails
+and plaiting down apparatus. These cylinders are driven by bevel wheels, so
+that each one is independent of its neighbor, and should any accident occur
+to one or more of the cylinders or wheels, the remaining ones can be run
+until a favorable opportunity arrives to repair the damage. A small
+separate double cylinder diagonal engine is fitted to this machine, the
+speed of which can be adjusted for any texture of cloth, and being of the
+design it is, will start at once on steam being turned one. The machine
+cylinders are rolled by a special machine for that purpose, and are
+perfectly true on the face. Their insides are fitted with patent buckets,
+which remove all the condensed water. In the machine exhibited, which is
+designed for the bleaching, washing, chloring, and dyeing, the cloth is
+supported by hollow metallic cylinders perforated with holes and corrugated
+to allow the liquor used to pass freely through as much of the cloth as
+possible; the open ends of the cylinders are so arranged that nearly all of
+their area is open to the action of the pump. The liquor, which is drawn
+through the cloth into the inside of the cylinders by the centrifugal
+pumps, is discharged back into the cistern by a specially constructed
+discharge pipe, so devised that the liquor, which is sent into it with
+great force by the pump, is diverted so as to pour straight down in order
+to prevent any eddies which could cause the cloth to wander from its
+course. The cloth is supported to and from the cylinders by flat perforated
+plates in such a manner that the force of the liquor cannot bag or displace
+the threads of the cloth, and by this means also the liquor has a further
+tendency to penetrate the fibers of the cloth. Means are provided for
+readily and expeditiously cleansing the entire machine. The next machine
+which we have to notice in this exhibit is Farmer's patent marking and
+measuring machine, the purpose of which is to stamp on the cloths the
+lengths of the same at regular distances. It is very desirable that drapers
+should have some simple means of discovering at a glance what amount of
+material they have in stock without the necessity of unrolling their cloth
+to measure it, and this machine seems to perfectly meet the demands of the
+case. The arrangement for effecting the printing and inking is shown in our
+engraving at A. It is contained within a small disk, which can be moved at
+will, so that it can be adapted to various widths of cloth or other
+material. A measuring roller runs beside the printing disk, and on this is
+stamped the required figures by a simple contrivance at the desired
+distances, say every five yards. The types are linked together into a
+roller chain which is carried by the disk, A, and they ink themselves
+automatically from a flannel pad. The machine works in this way: The end of
+the piece to be measured is brought down until it touches the surface of
+the table, the marker is turned to zero, and also the finger of the dial on
+the end of the measuring roller. The machine is then started, and the
+lengths are printed at the required distances until it becomes necessary to
+cut out the first piecing or joint in the fabric. The dial registers the
+total length of the piece.
+
+       *       *       *       *       *
+
+
+
+
+ENDLESS ROPE HAULAGE.
+
+
+In the North of England Report, the endless rope systems are classified as
+No. 1 and No 2 systems. No. 1, which has the rope under the tubs, is said
+to be in operation in the Midland counties. To give motion to the rope a
+single wheel is used, and friction for driving the rope is supplied either
+by clip pulleys or by taking the rope over several wheels. The diagram
+shows an arrangement for a tightening arrangement. One driving wheel is
+used, says _The Colliery Guardian_, and the rope is kept constantly tight
+by passing it round a pulley fixed upon a tram to which a heavy weight is
+attached. Either one or two lines of rails are used. When a single line is
+adopted the rope works backward and forward, only one part being on the
+wagon way and the other running by the side of the way. When two lines are
+used the ropes move always in one direction, the full tubs coming out on
+one line and the empties going in on the other. The rope passes under the
+tubs, and the connection is made by means of a clamp or by sockets in the
+rope, to which the set is attached by a short chain. The rope runs at a
+moderately high speed.
+
+[Illustration: TIGHTENING ARRANGEMENT--ENDLESS ROPE HAULAGE.]
+
+No. 2 system was peculiar to Wigan. A double line of rails is always used.
+The rope rests upon the tubs, which are attached to the rope either singly
+or in sets varying in number from two to twelve. The other engraving shows
+a mode of connection between the tubs and the rope by a rope loop as shown.
+
+[Illustration: ATTACHMENT TO ENDLESS ROPE "OVER."]
+
+The tubs are placed at a regular distance apart, and the rope works slowly.
+Motion is given to the rope by large driving pulleys, and friction is
+obtained by taking the rope several times round the driving pulley.
+
+       *       *       *       *       *
+
+
+
+
+A RELIABLE WATER FILTER.
+
+
+Opinions are so firmly fixed at present that water is capable of carrying
+the germs of disease that, in cases of epidemics, the recommendation is
+made to drink natural mineral waters, or to boil ordinary water. This is a
+wise measure, assuredly; but mineral waters are expensive, and, moreover,
+many persons cannot get used to them. As for boiled water, that is a
+beverage which has no longer a normal composition; a portion of its salts
+has become precipitated, and its dissolved gases have been given off. In
+spite of the aeration that it is afterward made to undergo, it preserves an
+insipid taste, and I believe that it is not very digestible. I have
+thought, then, that it would be important, from a hygienic standpoint, to
+have a filter that should effectually rid water of all the microbes or
+germs that it contains, while at the same time preserving the salts or
+gases that it holds in solution. I have reached such a result, and,
+although it is always delicate to speak of things that one has himself
+done, I think the question is too important to allow me to hold back my
+opinion in regard to the apparatus. It is a question of general hygiene
+before which my own personality must disappear completely.
+
+In Mr. Pasteur's laboratory, we filter the liquids in which microbes have
+been cultivated, so as to separate them from the medium in which they
+exist. For this purpose we employ a small unglazed porcelain tube that we
+have had especially constructed therefor. The liquid traverses the porous
+sides of this under the influence of atmospheric pressure, since we cause a
+vacuum around the tube by means of an air-pump. We collect in this way,
+after several hours, a few cubic inches of a liquid which is absolutely
+pure, since animals may be inoculated with it without danger to them, while
+the smallest quantity of the same liquid, when not filtered, infallibly
+causes death.
+
+This is the process that I have applied to the filtration of water. I have
+introduced into it merely such modifications as are necessary to render the
+apparatus entirely practical. My apparatus consists of an unglazed
+porcelain tube inverted upon a ring of enameled porcelain, forming a part
+thereof, and provided with an aperture for the outflow of the liquid. This
+tube is placed within a metallic one, which is directly attached to a cock
+that is soldered to the service pipe. A nut at the base that can be
+maneuvered by hand permits, through the intermedium of a rubber washer
+resting upon the enameled ring, of the tube being hermetically closed.
+
+Under these circumstances, when the cock is turned on, the water fills the
+space between the two tubes and slowly filters, under the influence of
+pressure, through the sides of the porous one, and is freed from all solid
+matter, including the microbes and germs, that it contains. It flows out
+thoroughly purified, through the lower aperture, into a vessel placed there
+to receive it.
+
+I have directly ascertained that water thus filtered is deprived of all its
+germs. For this purpose I have added some of it (with the necessary
+precautions against introducing foreign organisms) to very changeable
+liquids, such as veal broth, blood, and milk, and have found that there was
+no alteration. Such water, then, is incapable of transmitting the germs of
+disease.
+
+[Illustration: CHAMBERLAND'S WATER FILTER.]
+
+With an apparatus like the one here figured, and in which the filtering
+tube is eight inches in length by about one inch in diameter, about four
+and a half gallons of water per day may be obtained when the pressure is
+two atmospheres--the mean pressure in Mr. Pasteur's laboratory, where my
+experiments were made. Naturally, the discharge is greater or less
+according to the pressure. A discharge of three and a half to four and a
+half gallons of water seems to me to be sufficient for the needs of an
+ordinary household. For schools, hospitals, barracks, etc., it is easy to
+obtain the necessary volume of water by associating the tubes in series.
+The discharge will be multiplied by the number of tubes.
+
+In the country, or in towns that have no water mains, it will be easy to
+devise an arrangement for giving the necessary pressure. An increase in the
+porosity of the filtering tube is not to be thought of, as this would allow
+very small germs to pass. This filter being a perfect one, we must expect
+to see it soil quickly. Filters that do not get foul are just the ones that
+do not filter. But with the arrangement that I have adopted the solid
+matters deposit upon the external surface of the filter, while the inner
+surface always remains perfectly clean. In order to clean the tube, it is
+only necessary to take it out and wash it vigorously. As the tube is
+entirely of porcelain, it may likewise be plunged into boiling water so as
+to destroy the germs that may have entered the sides or, better yet, it may
+be heated over a gas burner or in an ordinary oven. In this way all the
+organic matter will be burned, and the tube will resume its former
+porosity.--_M. Chamberland, La Nature._
+
+       *       *       *       *       *
+
+
+
+
+SIMPLE DEVICES FOR DISTILLING WATER.
+
+
+The alchemists dreamed and talked of that universal solvent which they so
+long and vainly endeavored to discover; still, for all this, not only the
+alchemist of old, but his more immediate successor, the chemist of to-day,
+has found no solvent so universal as water. No liquid has nearly so wide a
+range of dissolving powers, and, taking things all round, no liquid
+exercises so slight an action upon the bodies dissolved--evaporate the
+water away, and the dissolved substance is obtained in an unchanged
+condition; at any rate, this is the general rule.
+
+The function of water in nature is essentially that of a solvent or a
+medium of circulation; it is not, in any sense, a food, yet without it no
+food can be assimilated by an animal. Without water the solid materials of
+the globe would be unable to come together so closely as to interchange
+their elements; and unless the temperatures were sufficiently high to
+establish an igneous fluidity, such as undoubtedly exists in the sun, there
+would be no circulation of matter to speak of, and the earth would be, as
+it were, locked up or dead.
+
+When we look upon water as the nearest approach to a universal solvent that
+even the astute scientist of to-day has been able to discover, who can
+wonder that it is never found absolutely pure in nature? For wherever it
+accumulates it dissolves something from its surroundings. Still, in a
+rain-drop just formed we have very nearly pure water; but even this
+contains dissolved air to the extent of about one-fiftieth of its volume,
+and as the drop falls downward it takes up such impurities as may be
+floating in the atmosphere; so that if our rain-drop is falling
+immediately after a long drought, it becomes charged with nitrate or
+nitrite of ammonia and various organic matters--perhaps also the spores or
+germs of disease. Thus it will be seen that rain tends to wonderfully clear
+or wash the atmosphere, and we all know how much a first rain is
+appreciated as an air purifier, and how it carries down with it valuable
+food for plants. The rain-water, in percolating through or over the land,
+flows mainly toward the rivers, and in doing so it becomes more or less
+charged with mineral matter, lime salts and common salt being the chief of
+them; while some of that water which has penetrated more deeply into the
+earth takes up far more solid matter than is ordinarily found in river
+water. The bulk of this more or less impure water tends toward the ocean,
+taking with it its load of salt and lime. Constant evaporation, of course,
+takes place from the surface of the sea, so that the salt and lime
+accumulate, this latter being, however, ultimately deposited as shells,
+coral, and chalk, while nearly pure or naturally distilled water once more
+condenses in the form of clouds. This process, by which a constant supply
+of purified water is kept up in the natural economy, is imitated on a small
+scale when water is converted into steam by the action of heat, and this
+vapor is cooled so as to reproduce liquid water, the operation in question
+being known as distillation.
+
+For this purpose an apparatus known as a still is required; and although by
+law one must pay an annual license fee for the right to use a still, it is
+not usual for the government authorities to enforce the law when a still is
+merely used for purifying water.
+
+One of the best forms of still for the photographer to employ consists of a
+tin can or bottle in which the water is boiled, and to this a tin tube is
+adapted by means of a cork, one end of this tin tube terminating in a coil
+passing through a tub or other vessel of cold water. A gas burner, as
+shown, is a convenient source of heat, and in order to insure a complete
+condensation of the vapor, the water in the cooling tub must be changed now
+and again.
+
+[Illustration]
+
+Sometimes the vapor is condensed by being allowed to play against the
+inside of a conical cover which is adapted to a saucepan, and is kept cool
+by the external application of cold water; and in this case the still takes
+the form represented by the subjoined diagrams; such compact and portable
+stills being largely employed in Ireland for the private manufacture of
+whisky.
+
+[Illustration]
+
+It is scarcely necessary to say that the condensed water trickles down on
+the inside of the cone, and flows out at the spout.
+
+An extemporized arrangement of a similar character may be made by passing a
+tobacco pipe through the side of a tin saucepan as shown below, and
+inverting the lid of the saucepan; if the lid is now kept cool by frequent
+changes of water inside it, and the pipe is properly adjusted so as to
+catch the drippings from the convex side of the lid, a considerable
+quantity of distilled water may be collected in an hour or so.
+
+The proportion of solid impurities present in water as ordinarily met with
+is extremely variable: rain water which has been collected toward the end
+of a storm contains only a minute fraction of a grain per gallon, while
+river or spring water may contain from less than thirty grains per gallon
+or so and upward. Ordinary sea water generally contains from three to four
+per cent. of saline matter, but that of the Dead Sea contains nearly
+one-fourth of its weight of salts.
+
+[Illustration]
+
+The three impurities of water which most interest the photographer are lime
+or magnesia salts, which give the so-called hardness; chlorides (as, for
+example, chloride of sodium or common salt), which throw down silver salts;
+and organic matter, which may overturn the balance of photographic
+operations by causing premature reduction of the sensitive silver
+compounds. To test for them is easy. Hardness is easily recognizable by
+washing one's hands in the water, the soap being curdled; but in many cases
+one must rather seek for a hard water than avoid it, as the tendency of
+gelatine plates to frill is far less in hard water than in soft water. It
+is, indeed, a common and useful practice to harden the water used for
+washing by adding half an ounce or an ounce of Epsom salts (sulphate of
+magnesia) to each bucket of water. Chlorides--chloride of sodium or common
+salt being that usually met with--may be detected by adding a drop or two
+of nitrate of silver to half a wineglassful of the water, a few drops of
+nitric acid being then added. A slight cloudiness indicates a trace of
+chlorides, and a decided milkiness shows the presence of a larger quantity.
+If it is wished to get a somewhat more definite idea of the amount, it is
+easy to make up a series of standards for comparison, by dissolving known
+weights of common salt in distilled or rain water, and testing samples of
+them side by side with the water to be examined.
+
+Organic matters may be detected by adding a little nitrate of silver to the
+water, filtering off from any precipitate of chloride of silver, and
+exposing the clear liquid to sunlight; a clean stoppered bottle being the
+most convenient vessel to use. The extent to which a blackening takes place
+may be regarded as approximately proportionate to the amount of organic
+matter present.
+
+Filtration on a small scale is not altogether a satisfactory mode of
+purifying water, as organic impurities often accumulate in the filter, and
+enter into active putrefaction when hot weather sets in.--_Photo. News._
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED FIRE-DAMP DETECTER.
+
+
+According to the London _Mining Journal_, Mr. W.E. Garforth, of Normanton,
+has introduced an ingenious invention, the object of which is to detect
+fire-damp in collieries with the least possible degree of risk to those
+engaged in the work. Mr. Garforth's invention, which is illustrated in the
+diagram given below, consists in the use of a small India rubber hand ball,
+without a valve of any description; but by the ordinary action of
+compressing the ball, and then allowing it to expand, a sample of the
+suspected atmosphere is drawn from the roof, or any part of the mine,
+without the great risk which now attends the operation of testing for gas
+should the gauze of the lamp be defective. The sample thus obtained is then
+forced through a small protected tube on to the flame, when if gas is
+present it is shown by the well-known blue cap and elongated flame. From
+this description, and from the fact that the ball is so small that it can
+be carried in the coat pocket, or, if necessary, in the waistcoat pocket,
+it will be apparent what a valuable adjunct Mr. Garforth's invention will
+prove to the safety-lamp. It has been supposed by some persons that
+explosions have been caused by the fire-trier himself, but owing to his own
+death in most cases the cause has remained undiscovered. This danger will
+now be altogether avoided. It is well known that the favorite form of lamp
+with the firemen is the Davy, because it shows more readily the presence of
+small quantities of gas; but the Davy was some years ago condemned, and is
+now strictly prohibited in all Belgian and many English mines. Recent
+experience, gained by repeated experiments with costly apparatus, has
+resulted in not only proving the Davy and some other descriptions of lamps
+to be unsafe, but some of our Government Inspectors and our most
+experienced mining engineers go so far as to say that "no lamp in a strong
+current of explosive gas is safe unless protected by a tin shield."
+
+[Illustration]
+
+If such is the case, Mr. Garforth seems to have struck the key-note when,
+in the recent paper read before the Midland Institute of Mining and Civil
+Engineers, and which we have now before us, he says: "It would seem from
+the foregoing remarks that in any existing safety-lamp where one
+qualification is increased another is proportionately reduced; so it is
+doubtful whether all the necessary requirements of sensitiveness,
+resistance to strong currents, satisfactory light, self-extinction, perfect
+combustion, etc., can ever be combined in one lamp."
+
+The nearest approach to Mr. Garforth's invention which we have ever heard
+of is that of a workman at a colliery in the north of England, who, more
+than twenty years ago, to avoid the trouble of getting to the highest part
+of the roof, used a kind of air pump, seven or eight feet long, to extract
+the gas from the breaks; and some five years ago Mr. Jones, of Ebbw Vale,
+had a similar idea. It appears that these appliances were so cumbersome,
+besides requiring too great length or height for most mines, and
+necessitating the use of both hands, that they did not come into general
+use. The ideas, however, are totally different, and the causes which have
+most likely led to the invention of the ball and protected tube were
+probably never thought of until recently; indeed, Mr. Garforth writes that
+he has only learned about them since his paper was read before the Midland
+Institute, and some weeks after his patent was taken out.
+
+No one, says Mr. Garforth, in his paper read before the Midland Institute,
+will, I presume, deny that the Davy is more sensitive than the tin shield
+lamp, inasmuch as in the former the surrounding atmosphere or explosive
+mixture has only one thickness of gauze to pass through, and that on a
+level with the flame; while the latter has a number of small holes and two
+or three thicknesses of gauze (according to the construction of the lamp),
+which the gas must penetrate before it reaches the flame. Moreover, the tin
+shield lamp, when inclined to one side, is extinguished (though not so
+easily as the Mueseler); and as the inlet holes are 6 inches from the top,
+it does not show a thin stratum of fire-damp near the roof as perceptibly
+as the Davy, which admits of being put in almost a horizontal position.
+Although the Davy lamp was, nearly fifty years ago, pronounced unsafe, by
+reason of its inability to resist an ordinary velocity of eight feet per
+second, yet it is still kept in use on account of its sensitiveness. Its
+advocates maintain that a mine can be kept safer by using the Davy, which
+detects small quantities of gas, and thereby shows the real state of the
+mine, than by a lamp which, though able to resist a greater velocity, is
+not so sensitive, and consequently is apt to deceive. Assuming the Davy
+lamp to be condemned (as it has already been in Belgium and in some English
+mines), the Stephenson and some of the more recently invented lamps
+pronounced unsafe, then if greater shielding is recommended the question
+is, what means have we for detecting small quantities of fire-damp?
+
+It would seem from the foregoing remarks that in any existing safety-lamp,
+where one qualification is increased another is proportionately reduced; so
+it is doubtful whether all the necessary requirements of sensitiveness,
+resistance to strong currents, satisfactory light, self-extinction, perfect
+combustion, etc., can ever be combined in one lamp. The object of the
+present paper is to show that with the assistance of the fire-damp
+detecter, the tin shield, or any other description of lamp, is made as
+sensitive as the Davy, while its other advantages of resisting velocity,
+etc., are not in any way interfered with. As a proof of this I may mention
+that a deputy of experience recently visited a working place to make his
+inspection. He reported the stall to be free from gas, but when the manager
+and steward visited it with the detecter, which they applied to the roof
+(where it would have been difficult to put even a small Davy), it drew a
+sample of the atmosphere which, on being put to the test tube in the
+tin-shield lamp, at once showed the presence of fire-damp. Out of
+twenty-eight tests in a mine working a long-wall face the Davy showed gas
+only eleven times, while the detecter showed it in every case. The
+detecter, as will be perceived from the one exhibited, and the accompanying
+sectional drawing, consists simply of an oval-shaped India rubber ball,
+fitted with a mouthpiece. The diameter is about 21/4 inches by 3 inches, its
+weight is two ounces, and it is so small that it can be carried without any
+inconvenience in the coat or even in the waistcoat pocket. Its capacity is
+such that all the air within it may be expelled by the compression of one
+hand.
+
+The mouthpiece is made to fit a tube in the bottom of the lamp, and when
+pressed against the India rubber ring on the ball-flange, a perfectly tight
+joint is made, which prevents the admission of any external air. The tube
+in the bottom of the lamp is carried within a short distance of the height
+of the wick-holder. It is covered at the upper end with gauze, besides
+being fitted with other thicknesses of gauze at certain distances within
+the tube; and if it be found desirable to further protect the flame against
+strong currents of air, a small valve may be placed at the inlet, as shown
+in the drawing. This valve is made of sufficient weight to resist the force
+of a strong current, and is only lifted from its seat by the pressure of
+the hand on the mouthpiece. It will be apparent from the small size and
+elasticity of the detecter that the test can easily be made with one hand,
+and when the ball is allowed to expand a vacuum is formed within it, and a
+sample of the atmosphere drawn from the breaks, cavities, or highest parts
+of the roof, or, of course, any portion of the mine. When the sample is
+forced through the tube near the flame, gas if present at once reveals
+itself by the elongation of the flame in the usual way, at the same time
+giving an additional proof by burning with a blue flame on the top of the
+test tube. If gas is not present, the distinction is easily seen by the
+flame keeping the same size, but burning with somewhat greater brightness,
+owing to the increased quality of oxygen forced upon it.
+
+I venture to claim for this method of detecting fire-damp among other
+advantages: 1. The detecter, on account of its size, can be placed in a
+break in the roof where an ordinary lamp--even a small Davy--could not be
+put, and a purer sample of the suspected atmosphere is obtained than would
+be the case even a few inches below the level of the roof, 2. The obtaining
+and testing of a sample in the manner above described takes away the
+possibility of an explosion, which might be the result if a lamp with a
+defective gauze were placed in an explosive atmosphere. No one knows how
+many explosions have not been caused by the fire-trier himself. This will
+now be avoided. (Although lamps fitted with a tin shield will be subjected
+to the same strict examination as hitherto, still they do not admit of the
+same frequent inspection as those without shields, for in the latter case
+each workman can examine his own lamp as an extra precaution; whereas the
+examination of the tin shield lamps will rest entirely with the lamp man.)
+3. The lamp can be kept in a pure atmosphere while the sample is obtained
+by the detecter, and at a greater height than the flame in a safety-lamp
+could be properly distinguished. The test can afterward be made in a safe
+place, at some distance from the explosive atmosphere; and, owing to the
+vacuum formed, the ball (without closing the mouthpiece) has been carried a
+mile or more without the gas escaping. 4. The detecter supplies a better
+knowledge of the condition of the working places, especially in breaks and
+cavities in the roof; which latter, with the help of a nozzle and staff,
+may be reached to a height of ten feet or more, by the detecter being
+pressed against the roof and sides, or by the use of a special form of
+detecter. 5. Being able at will to force the contents of the detecter on to
+the flame, the effects of an explosion inside the lamp need not be feared.
+(This danger being removed, admits, I think, of the glass cylinder being
+made of a larger diameter, whereby a better light is obtained; it may also
+be considered quite as strong, when used with the detecter, as a lamp with
+a small diameter, when the latter is placed in an explosive atmosphere.) 6.
+The use of the detecter will permit the further protection of the present
+tin shield lamp, by an extra thickness of gauze, if such addition is found
+advantageous in resisting an increased velocity. 7. In the Mueseler,
+Stephenson, and other lamps, where the flame is surrounded by glass, there
+is no means of using the wire for shot firing. The detecter tube, although
+protected by two thicknesses of gauze, admits of this being done by the use
+of a special form of valve turned by the mouthpiece of the detecter. The
+system of firing shots or using open lamps in the same pit where safety
+lamps are used is exceedingly objectionable; still, under certain
+conditions shots may be fired without danger. Whether safety lamps or
+candles are used, it is thought the use of the detecter will afford such a
+ready means of testing that more examinations will be made before firing a
+shot, thereby insuring greater safety. 8. In testing for gas with a safety
+lamp there is a fear of the light being extinguished, when the lamp is
+suddenly placed in a quantity of gas, or in endeavoring to get a very
+small light; this is especially the case with some kinds of lamps. With the
+detecter this is avoided, as a large flame can be used, which is considered
+by some a preferable means of testing for small quantities; and the test
+can be made without risk. Where gas is present in large quantities, the
+blue flame at the end of the test tube will be found a further proof. This
+latter result is produced by the slightest compression of the ball. (I need
+not point out the inconvenience and loss of time in having to travel a mile
+or more to relight.) As regards the use of the detecter with open lights,
+several of the foregoing advantages or modifications of them will apply.
+Instead of having to use the safety lamp as at present, it is thought that
+the working place will be more frequently examined, for a sample of the
+suspected atmosphere can be carried to a safe place and forced on to the
+naked light, when, if gas be present, it simply burns at the end of the
+mouthpiece like an ordinary gas jet. There are other advantages, such as
+examining the return airways without exposing the lamp, etc., which will be
+apparent, and become of more or less importance according to the conditions
+under which the tests are made.
+
+In conclusion, I wish to paint out that the practice adopted at some
+collieries, of having all the men supplied with the most approved lamp
+(such as the Mueseler or tin shield lamp) is not a safe one. If the
+strength of a chain is only equal to the weakest link, it may be argued
+that the safety of a mine is only equal to that of the most careless man or
+most unsafe lamp in it. If, therefore, the deputies, whose duty it is to
+look for gas and travel the most dangerous parts of the mine, are obliged
+to use the Davy on account of its sensitiveness, may it not be said that,
+as their lamps are exposed equally with the workmen's to the high
+velocities of air, they are the weak links in the safety of the mine? For
+the reasons given, I venture to submit that the difficulties and dangers I
+have mentioned will be largely reduced, if not wholly overcome, by the use
+of the fire-damp detecter.
+
+       *       *       *       *       *
+
+
+
+
+CAMERA ATTACHMENT FOR PAPER PHOTO NEGATIVES.
+
+
+In computing the weight of the various items for a photographic tour, the
+glass almost invariably comes out at the head of the list, and the farther
+or longer the journey, so much more does the weight of the plates stand out
+pre-eminent; indeed, if one goes out on a trip with only three dozen
+half-plates, the glass will probably weigh nearly as much as camera, backs,
+and tripod, in spite of the stipulation with the maker to supply plates on
+"thin glass."
+
+Next in importance to glass as a support comes paper, and it is quite easy
+to understand that the tourist in out of the way parts might be able to
+take an apparatus containing a roll of sensitive paper, when it would be
+altogether impracticable for him to take an equivalent surface of coated
+glass, and in such a case the roller slide becomes of especial value.
+
+The roller slide of Melhuish is tolerably well known, and is, we believe,
+now obtainable as an article of commerce. The slide is fitted up with two
+rollers, _a a_, and the sensitive sheets, _b b_, are gummed together,
+making one long band, the ends of which are gummed to pieces of paper
+always kept on the rollers. The sensitive sheets are wound off the left or
+reserve roller on to the right or exposed roller, until all are exposed.
+
+[Illustration]
+
+The rollers are supported on springs, _a a_, to render their motion
+equal; they are turned by the milled heads, _m m_, and clamped when each
+fresh sheet is brought into position by the nuts, _a squared a squared_. _c_, is a board
+which is pressed forward by springs, _c c_, so as to hold the sheet to be
+exposed, and keep it smooth against the plate of glass, _d_; when the sheet
+has been exposed, the board is drawn back from the glass in order to
+release the exposed sheet, and allow it to be rolled on the exposed roller;
+the board is kept back while this is being done by turning the square rod,
+_c squared_, half round, so that the angles of the square will not pass back
+through the square opening until again turned opposite to it; _e e_ are
+doors, by opening which the operator can see (through the yellow glass, _y
+y_) to adjust the position of the sensitive sheets when changing them.
+
+The remarkable similarity of such a slide to the automatic printing-frame
+described last week will strike the reader; and, like the printing-frame,
+it possesses the advantage of speed in working--no small consideration to
+the photographer in a distant, and possibly hostile, country.
+
+Fine paper well sized with an insoluble size and coated with a sensitive
+emulsion is, we believe, the very best material to use in the roller slide;
+and such a paper might be made in long lengths at a very low price, a
+coating machine similar to that constructed for use in making carbon tissue
+being employed. We have used such paper with success, and hope that some
+manufacturer will introduce it into commerce before long. But the question
+suggests itself, how are the paper negatives to be rendered transparent,
+and how is the grain of the paper to be obliterated? Simply by pressure, as
+extremely heavy rolling will render such paper almost as transparent as
+glass, a fact abundantly demonstrated by Mr. Woodbury in his experiments on
+the Photo-Filigrane process, and confirmed by some trials which we have
+made.
+
+It must be confessed that roller slide experiments which we have made with
+sensitive films supported on gelatine sheets, or on such composite sheets
+as the alternate rubber and collodion pellicle of Mr. Warnerke, have been
+hardly satisfactory--possibly, however, from our own want of skill; while
+no form of the Calotype process which we have tried has proved so
+satisfactory as gelatino-bromide paper.--_Photo. News_.
+
+       *       *       *       *       *
+
+
+
+
+INSTANTANEOUS PHOTO SHUTTER.
+
+
+M. Audra, in the name of M. Braun, of Angouleme, has presented to the Photo
+Society of France a new instantaneous shutter. The shutter is formed by a
+revolving metallic disk out of which a segment has been taken. This disk is
+placed in the center of the diaphragms, in order to obtain the greatest
+rapidity combined with the least possible distance to travel. On the axis
+to which this circular disk is fixed is a small wheel, to which is attached
+a piece of string, and when the disk is turned round for the exposure the
+string is wound round the wheel. If the string be pulled, naturally the
+disk will revolve back to its former position so much the more quickly the
+more violently the string is pulled. M. Braun has replaced the hand by a
+steel spring attached to the drum of the lens (Fig. 2) By shortening or
+lengthening the string, more or less rapid exposures may be obtained.
+
+[Illustration: AAA, lens; B, aperture of lens; C, metallic disk; D,
+wheel on the axis; E, cord or string; EEEE, knots in string; G, steel
+spring; H, catch; K, socket for catch.]
+
+       *       *       *       *       *
+
+
+
+
+SULPHUROUS ACID.--EASY METHOD OF PREPARATION FOR PHOTOGRAPHIC PURPOSES.
+
+
+Within a short period sulphurous acid has become an important element in
+the preparation of an excellent pyro developer for gelatine plates; and as
+it is more or less unstable in its keeping qualities, some easy method of
+preparing a small quantity which shall have a uniform strength is
+desirable. A method recently described in the _Photographic News_ will
+afford the amateur photographer a ready way of preparing a small quantity
+of the acid.
+
+[Illustration]
+
+In the illustration given above, A and B are two bottles, both of which can
+be closed tightly with corks. A hole is made in the cork in the bottle, A,
+a little smaller than the glass tube which connects A and B. It is filed
+out with a rat-tail file until it is large enough to admit the tube very
+tightly. The tube may be bent easily, by being heated over a common
+fish-tail gas burner or over the top of the chimney of a kerosene lamp, so
+as to form two right angles, one end extending close to the bottom of the
+bottle B as shown.
+
+Having fitted up the apparatus, about two ounces of hyposulphite of soda
+are placed in the bottle A, while the bottle B is about three-fourths
+filled with water--distilled or melted ice water is to be preferred; some
+sulphuric acid--about two ounces--is now diluted with about twice its bulk
+of water, by first putting the water into a dish and pouring in the acid in
+a steady stream, stirring meanwhile. It is well to set the dish in a sink,
+to avoid any damage which might occur through the breaking of the dish by
+the heat produced; when cool, the solution is ready for use and may be kept
+in a bottle.
+
+The cork which serves to adapt the bent tube to the bottle A is now just
+removed for an instant, the other end remaining in the water in bottle B,
+and about two or three ounces of the dilute acid are poured in upon the
+hyposulphite, after which the cork is immediately replaced.
+
+Sulphurous acid is now evolved by the action of the acid on the hypo, and
+as the gas is generated it is led as a series of bubbles through the water
+in the bottle B as shown. The air space above the water in bottle B soon
+becomes filled by displacement with sulphurous acid gas, which is a little
+over twice as heavy as air; so in order to expedite the complete saturation
+of the water, it is convenient to remove the bottle A with its tube from
+bottle B, and after having closed the latter by its cork or stopper, to
+agitate it thoroughly by turning the bottle upside down. As the sulphurous
+acid gas accumulated in the air space over the water is absorbed by the
+water, a partial vacuum is created, and when the stopper is eased an inrush
+of air may be noted. When, after passing fresh gas through the liquid for
+some minutes, no further inrush of air is noted on easing the stopper as
+before described after agitating the bottle, it may be concluded that the
+water is thoroughly saturated with sulphurous acid and is strong enough for
+immediate use. More gas can be generated by adding more dilute sulphuric
+acid to the hypo until the latter is decomposed; then it should be thrown
+aside, and a fresh charge put in the bottle. On preparing the solution it
+is well to set the bottles on the outside ledge of the window, or in some
+other open situation where no inconvenience will result from the escape of
+the excess of sulphurous gas as it bubbles through the water.
+
+The solution of sulphurous acid, if preserved at all, ought to be kept in
+small bottles, completely filled and perfectly closed; but as it is very
+easy to saturate a considerable quantity of water with sulphurous acid gas
+in a short time, there is but little inducement to use a solution which may
+possibly have become weakened by keeping.
+
+Care should be taken not to add too much dilute acid to the hypo at a time,
+else excessive effervescence will occur, and the solution will froth over
+the top of the bottle.
+
+       *       *       *       *       *
+
+
+
+
+THE NATIONAL MONUMENT AT ROME.
+
+
+About three years ago the Italian Government invited the architects and
+artists of the world to furnish competitive designs for a national monument
+to be erected to the memory of King Victor Emanuel II. at Rome. More than
+$1,800,000 were appropriated for the monument exclusive of the foundation.
+It is very seldom that an artist has occasion to carry out as grand and
+interesting a work as this was to be: the representation of the creator of
+the Italian union in the new capitol of the new state surrounded by the
+ruins and mementos of a proud and mighty past. Prizes of $10,000, $6,000,
+and $4,000 were donated for the first, second, and third prize designs
+respectively. Designs were entered, not only from Italy, but also from
+Germany, France, Norway, Sweden, England, and America, and even from
+Caucasus and Japan.
+
+[Illustration: THE UNION OF ITALY. SACCONI'S PRIZE DESIGN FOR THE
+NATIONAL MONUMENT, ROME, ITALY.]
+
+The height and size of the monument were not determined on, nor was the
+exact location, and the competitors had full liberty in relation to the
+artistic character of the monument, and it was left for them to decide
+whether it should be a triumphal arch, a column, a temple, a mausoleum, or
+any other elaborate design. This great liberty given to the competitors was
+of great value and service to the monument commission, as it enabled them
+to decide readily what the character of the monument should be but it was a
+dangerous point for the artists, at which most of them foundered. The
+competition was resultless. Two prizes were given, but new designs had to
+be called for, which were governed more or less by a certain programme
+issued by the committee.
+
+In place of the Piazza de Termini, a square extending from the church of
+St. Maria degli Angeli to the new Via Nazionale, to which preference was
+given by the competitors, the heights of Aracoeli were chosen. The monument
+was to be erected at this historic place in front of the side wall of the
+church, with the center toward the Corso, high above the surrounding
+buildings. The programme called for an equestrian statue of the King
+located in front of an architectural background which was to cover the old
+church walls, and was to be reached by a grand staircase.
+
+Even the result of this second competition was not definite, but as the
+designers were guided by the programme, the results obtained were much more
+satisfactory. The commission decided not to award the first prize, but
+honored the Italian architects Giuseppi Sacconi and Manfredo Manfredi, and
+the German Bruno Schmitz, with a prize of $2,000 each; and requested them
+to enter into another competition and deliver their models within four
+months, so as to enable the commission to come to a final decision. On June
+18, the commission decided to accept Sacconi's design for execution, and
+awarded a second prize of $2,000 to Manfredi.
+
+Sacconi's design, shown opposite page, cut taken from the _Illustrirte
+Zeitung_, needs but little explanation. An elegant gallery of sixteen
+Corinthian columns on a high, prominent base is crowned by a high attica
+and flanked by pavilions. It forms the architectural background for the
+equestrian statue, and is reached by an elaborately ornamented staircase.
+
+Manfredi's design shows a handsomely decorated wall in place of the
+gallery, and in front of the wall an amphitheater is arranged, in the
+center of which the equestrian statue is placed. Bruno Schmitz' design
+shows a rich mosaic base supporting an Ionic portico, from the middle of
+which a six column Corinthian "pronaos" projects, which no doubt would have
+produced a magnificent effect in the streets of Rome.
+
+       *       *       *       *       *
+
+
+
+
+ON THE EVOLUTION OF FORMS OF ORNAMENT.
+
+[Footnote: From a paper by Prof. Jacobsthal in the _Transactions_ of the
+Archaeological Society of Berlin.--_Nature_.]
+
+
+The statement that modern culture can be understood only through a study of
+all its stages of development is equally true of its several branches.
+
+Let us assume that decorative art is one of these. It contains in itself,
+like language and writing, elements of ancient and even of prehistoric
+forms, but it must, like these other expressions of culture, which are
+forever undergoing changes, adapt itself to the new demands which are made
+upon it, not excepting the very arbitrary ones of fashion; and it is owing
+to this cause that, sometimes even in the early stages of its development,
+little or nothing of its original form is recognizable. Investigations the
+object of which is to clear up this process of development as far as
+possible are likely to be of some service; a person is more likely to
+recognize the beauties in the details of ornamental works of art if he has
+an acquaintance with the leading styles, and the artist who is freed from
+the bondage of absolute tradition will be put into a better position to
+discriminate between accidental and arbitrary and organic and legitimate
+forms, and will thus have his work in the creation of new ones made more
+easy for him.
+
+Hence I venture to claim some measure of indulgence in communicating the
+results of the following somewhat theoretical investigations, as they are
+not altogether without a practical importance. I must ask the reader to
+follow me into a modern drawing-room, not into one that will dazzle us with
+its cold elegance, but into one whose comfort invites us to remain in it.
+
+The simple stucco ceiling presents a central rosette, which passes over by
+light conventional floral forms into the general pattern of the ceiling.
+The frieze also, which is made of the same material, presents a similar but
+somewhat more compact floral pattern as its chief motive. Neither of these,
+though they belong to an old and never extinct species, has as yet attained
+the dignity of a special name.
+
+The walls are covered with a paper the ornamentation of which is based upon
+the designs of the splendid textile fabrics of the middle ages, and
+represents a floral pattern of spirals and climbing plants, and bears
+evident traces of the influence of Eastern culture. It is called a
+pomegranate or pine-apple pattern, although in this case neither
+pomegranates nor pine-apples are recognizable.
+
+Similarly with respect to the pattern of the coverings of the chairs and
+sofas and of the stove-tiles; these, however, show the influence of Eastern
+culture more distinctly.
+
+The carpet also, which is not a true Oriental one, fails to rivet the
+attention, but gives a quiet satisfaction to the eye, which, as it were,
+casually glances over it, by its simple pattern, which is derived from
+Persian-Indian archetypes (Cashmere pattern, Indian palmettas), and which
+is ever rhythmically repeating itself (see Fig. 1).
+
+[Illustration: FIG. 1.]
+
+The floral pattern on the dressing-gown of the master of the house, as well
+as on the light woolen shawl that is thrown round the shoulders of his
+wife, and even the brightly colored glass knicknacks on the mantel-piece,
+manufactured in Silesia after the Indian patterns of the Reuleaux
+collection, again show the same motive; in the one case in the more
+geometrical linear arrangement, in the other in the more freely entwined
+spirals.
+
+Now you will perhaps permit me to denominate these three groups of patterns
+that occur in our new home fabrics as modern patterns. Whether we shall in
+the next season be able, in the widest sense of the word, to call these
+patterns modern naturally depends on the ruling fashion of the day, which
+of course cannot be calculated upon (Fig. 2).
+
+[Illustration: FIG. 2.]
+
+I beg to be allowed to postpone the nearer definition of the forms that
+occur in the three groups, which, however, on a closer examination all
+present a good deal that they have in common. Taking them in a general way,
+they all show a leaf-form inclosing an inflorescence in the form of an ear
+or thistle; or at other times a fruit or a fruit-form. In the same way with
+the stucco ornaments and the wall-paper pattern.
+
+The Cashmere pattern also essentially consists of a leaf with its apex
+laterally expanded; it closes an ear-shaped flower-stem, set with small
+florets, which in exceptional cases protrude beyond the outline of the
+leaf; the whole is treated rigorously as an absolute flat ornament, and
+hence its recognition is rendered somewhat more difficult. The blank
+expansion of the leaf is not quite unrelieved by ornament, but is set off
+with small points, spots, and blossoms. This will be thought less strange
+if we reflect on the Eastern representations of animals, in the portrayal
+of which the flat expanses produced by the muscle-layers are often treated
+from a purely decorative point of view, which strikes us as an exaggeration
+of convention.
+
+[Illustration: FIG. 3.]
+
+One cannot go wrong in taking for granted that plant-forms were the
+archetypes of all these patterns. Now we know that it holds good, as a
+general principle in the history of civilization, that the tiller of the
+ground supplants the shepherd, as the shepherd supplants the hunter; and
+the like holds also in the history of the branch of art we are
+discussing--representations of animals are the first to make their
+appearance, and they are at this period remarkable for a wonderful
+sharpness of characterization. At a later stage man first begins to exhibit
+a preference for plant-forms as subjects for representation, and above all
+for such as can in any way be useful or hurtful to him. We, however, meet
+such plant-forms used in ornament in the oldest extant monuments of art in
+Egypt, side by side with representations of animals; but the previous
+history of this very developed culture is unknown. In such cases as afford
+us an opportunity of studying more primitive though not equally ancient
+stages of culture, as for instance among the Greeks, we find the above
+dictum confirmed, at any rate in cases where we have to deal with the
+representation of the indigenous flora as contradistinguished from such
+representations of plants as were imported from foreign civilizations. In
+the case that is now to occupy us, we have not to go back so very far in
+the history of the world.
+
+[Illustration: FIG. 4.]
+
+The ornamental representations of plants are of two kinds. Where we have to
+deal with a simple pictorial reproduction of plants as symbols (laurel
+branches, boughs of olive and fir, and branches of ivy), _i. e._, with a
+mere characteristic decoration of a technical structure, stress is laid
+upon the most faithful reproduction of the object possible--the artist is
+again and again referred to the study of Nature in order to imitate her.
+Hence, as a general rule, there is less difficulty in the explanation of
+these forms, because even the minute details of the natural object now and
+then offer points that one can fasten upon. It is quite another thing when
+we have to deal with actual decoration which does not aim at anything
+further than at employing the structural laws of organisms in order to
+organize the unwieldy substance, to endow the stone with a higher vitality.
+These latter forms depart, even at the time when they originate, very
+considerably from the natural objects. The successors of the originators
+soon still further modify them by adapting them to particular purposes,
+combining and fusing them with other forms so as to produce particular
+individual forms which have each their own history (_e.g._, the acanthus
+ornament, which, in its developed form, differs very greatly from the
+acanthus plant itself); and in a wider sense we may here enumerate all such
+forms as have been raised by art to the dignity of perfectly viable beings,
+_e.g._, griffins, sphinxes, dragons, and angels.
+
+[Illustration: Fig. 5.]
+
+The deciphering and derivation of such forms as these is naturally
+enough more difficult; in the case of most of them we are not even in
+possession of the most necessary preliminaries to the investigation, and
+in the case of others there are very important links missing (_e.g._,
+for the well-known Greek palmettas). In proportion as the representation
+of the plant was a secondary object, the travesty has been more and more
+complete. As in the case of language, where the root is hardly
+recognizable in the later word, so in decorative art the original form
+is indistinguishable in the ornament. The migration of races and the
+early commercial intercourse between distant lands have done much to
+bring about the fusion of types; but again in contrast to this we find,
+in the case of extensive tracts of country, notably in the Asiatic
+continent, a fixity, throughout centuries, of forms that have once been
+introduced, which occasions a confusion between ancient and modern works
+of art, and renders investigations much more difficult. An old French
+traveler writes: "J'ai vu dans le tresor d'Ispahan les vetements de
+Tamerlan; ils ne different en rien de ceux d'aujourd'hui." Ethnology,
+the natural sciences, and last, but not least, the history of technical
+art are here set face to face with great problems.
+
+[Illustration: FIG. 6.]
+
+In the case in point, the study of the first group of artistic forms that
+have been elaborated by Western art leads to definite results, because the
+execution of the forms in stone can be followed on monuments that are
+relatively not very old, that are dated, and of which the remains are still
+extant. In order to follow the development, I ask your permission to go
+back at once to the very oldest of the known forms. They come down to us
+from the golden era of Greek decorative art--from the fourth or fifth
+century B.C.--when the older simple styles of architecture were supplanted
+by styles characterized by a greater richness of structure and more
+developed ornament. A number of flowers from capitals in Priene, Miletus,
+Eleusis, Athens (monument of Lysicrates), and Pergamon; also flowers from
+the calathos of a Greek caryatid in the Villa Albani near Rome, upon many
+Greek sepulchral wreaths, upon the magnificent gold helmet of a Grecian
+warrior (in the Museum of St. Petersburg)--these show us the simplest type
+of the pattern in question, a folded leaf, that has been bulged out,
+inclosing a knob or a little blossom (see Figs. 3 and 4). This is an
+example from the Temple of Apollo at Miletus, one that was constructed
+about ten years ago, for educational purposes. Here is the specimen of the
+flower of the monument to Lysicrates at Athens, of which the central part
+consists of a small flower or fruits (Figs. 5 and 6).
+
+[Illustration: FIG. 7.]
+
+The form passes over into Roman art. The larger scale of the buildings,
+and the pretensions to a greater richness in details, lead to a further
+splitting up of the leaf into acanthus-like forms. Instead of a fruit-form
+a fir-cone appears, or a pine-apple or other fruit in an almost
+naturalistic form.
+
+In a still larger scale we have the club-shaped knob developing into a
+plant-stem branching off something after the fashion of a candelabrum, and
+the lower part of the leaf, where it is folded together in a somewhat
+bell-shaped fashion, becomes in the true sense of the word a campanulum,
+out of which an absolute vessel-shaped form, as _e.g._ is to be seen in the
+frieze of the Basilica Ulpia in Rome, becomes developed.
+
+[Illustration: FIG. 8.]
+
+Such remains of pictorial representation as are still extant present us
+with an equally perfect series of developments. The splendid Graeco-Italian
+vessels, the richly ornamented Apulian vases, show flowers in the spirals
+of the ornaments, and even in the foreground of the pictorial
+representations, which correspond exactly to the above mentioned Greek
+relief representations. [The lecturer sent round, among other
+illustrations, a small photograph of a celebrated vase in Naples
+(representing the funeral rites of Patroclus), in which the flower in
+question appears in the foreground, and is perhaps also employed as
+ornament.] (Figs. 7 and 8.)
+
+The Pompeian paintings and mosaics, and the Roman paintings, of which
+unfortunately very few specimens have come down to us, show that the
+further developments of this form were most manifold, and indeed they form
+in conjunction with the Roman achievements in plastic art the highest point
+that this form reached in its development, a point that the Renaissance,
+which followed hard upon it, did not get beyond.
+
+[Illustration: FIG. 9.]
+
+Thus the work of Raphael from the loggias follows in unbroken succession
+upon the forms from the Thermae of Titus. It is only afterward that a freer
+handling of the traditional pattern arose, characterized by the
+substitution of, for instance, maple or whitethorn for the acanthus-like
+forms. Often even the central part falls away completely, or is replaced by
+overlapping leaves. In the forms of this century we have the same process
+repeated. Schinkel and Botticher began with the Greek form, and have put it
+to various uses; Stuler, Strack, Gropius, and others followed in their wake
+until the more close resemblance to the forms of the period of the
+Renaissance in regard to Roman art which characterizes the present day was
+attained (Fig. 9).
+
+Now, what plant suggested this almost indispensable form of ornament, which
+ranks along with the acanthus and palmetta, and which has also become so
+important by a certain fusion with the structural laws of both?
+
+[Illustration: FIG. 10.]
+
+We meet with organism of the form in the family of the Araceae, or aroid
+plants. An enveloping leaf (bract), called the spathe, which is often
+brilliantly colored, surrounds the florets, or fruits, that are disposed
+upon a spadix. Even the older writers--Theophrastus, Dioscorides, Galen,
+and Pliny--devote a considerable amount of attention to several species of
+this interesting family, especially to the value of their swollen stems as
+a food-stuff, to their uses in medicine, etc. Some species of Arum were
+eaten, and even nowadays the value of the swollen stems of some species of
+the family causes them to be cultivated, as, for instance, in Egypt and
+India, etc. (the so-called Portland sago, Portland Island arrowroot, is
+prepared from the swollen stems of _Arum maculatum_). In contrast with the
+smooth or softly undulating outlines of the spathe of Mediterranean Araceae,
+one species stands out in relief, in which the sharply-marked fold of the
+spathe almost corresponds to the forms of the ornaments which we are
+discussing. It is _Dracunculus vulgaris_, and derives its name from its
+stem, which is spotted like a snake. This plant, which is pretty widely
+distributed in olive woods and in the river valleys of the countries
+bordering on the Mediterranean, was employed to a considerable extent in
+medicine by the ancients (and is so still nowadays, according to Von
+Heldreich, in Greece). It was, besides, the object of particular regard,
+because it was said not only to heal snake-bite, but the mere fact of
+having it about one was supposed to keep away snakes, who were said
+altogether to avoid the places where it grew. But, apart from this, the
+striking appearance of this plant, which often grows to an enormous size,
+would be sufficient to suggest its employment in art. According to
+measurements of Dr. Julius Schmidt, who is not long since dead, and was the
+director of the Observatory at Athens, a number of these plants grow in the
+Valley of Cephisus, and attain a height of as much as two meters, the
+spathe alone measuring nearly one meter. [The lecturer here exhibited a
+drawing (natural size) of this species, drawn to the measurements above
+referred to.]
+
+[Illustration: FIG. 11.]
+
+Dr. Sintenis, the botanist, who last year traveled through Asia Minor and
+Greece, tells me that he saw beautiful specimens of the plant in many
+places, _e.g._, in Assos, in the neighborhood of the Dardanelles, under the
+cypresses of the Turkish cemeteries.
+
+The inflorescence corresponds almost exactly to the ornament, but the
+multipartite leaf has also had a particular influence upon its development
+and upon that of several collateral forms which I cannot now discuss. The
+shape of the leaf accounts for several as yet unexplained extraordinary
+forms in the ancient plane-ornament, and in the Renaissance forms that have
+been thence developed. It first suggested the idea to me of studying the
+plant attentively after having had the opportunity five years ago of seeing
+the leaves in the Botanic Gardens at Pisa. It was only afterward that I
+succeeded in growing some flowers which fully confirmed the expectations
+that I had of them (Figs. 10 and 11).
+
+[Illustration: FIG. 12.]
+
+The leaf in dracunculus has a very peculiar shape; it consists of a number
+of lobes which are disposed upon a stalk which is more or less forked
+(tends more or less to dichotomize). If you call to your minds some of the
+Pompeian wall decorations, you will perceive that similar forms occur there
+in all possible variations. Stems are regularly seen in decorations that
+run perpendicularly, surrounded by leaves of this description. Before this,
+these suggested the idea of a misunderstood (or very conventional)
+perspective representation of a circular flower. Now the form also occurs
+in this fashion, and thus negatives the idea of a perspective
+representation of a closed flower. It is out of this form in combination
+with the flower-form that the series of patterns was developed which we
+have become acquainted with in Roman art, especially in the ornament of
+Titus' Thermae and in the Renaissance period in Raphael's work. [The
+lecturer here explained a series of illustrations of the ornaments referred
+to (Figs. 12, 13, 14).]
+
+The attempt to determine the course of the first group of forms has been to
+a certain extent successful, but we meet greater difficulties in the study
+of the second.
+
+[Illustration: FIG. 13.]
+
+It is difficult to obtain a firm basis on which to conduct our
+investigations from the historical or geographical point of view into this
+form of art, which was introduced into the West by Arabico-Moorish culture,
+and which has since been further developed here. There is only one method
+open to us in the determination of the form, which is to pass gradually
+from the richly developed and strongly differentiated forms to the smaller
+and simpler ones, even if these latter should have appeared
+contemporaneously or even later than the former. Here we have again to
+refer to the fact that has already been mentioned, to wit, that Oriental
+art remained stationary throughout long periods of time. In point of fact,
+the simpler forms are invariably characterized by a nearer and nearer
+approach to the more ancient patterns and also to the natural flower-forms
+of the Araceae. We find the spathe, again, sometimes drawn like an acanthus
+leaf, more often, however, bulged out, coming to be more and more of a mere
+outline figure, and becoming converted into a sort of background; then the
+spadix, generally conical in shape, sometimes, however, altogether replaced
+by a perfect thistle, at other times again by a pomegranate. Auberville, in
+his magnificent work "L'Ornement des Tissus," is astonished to find the
+term pomegranate-pattern almost confined to these forms, since their
+central part is generally formed of a thistle-form. As far as I can
+discover in the literature that is at my disposal, this question has not
+had any particular attention devoted to it except in the large work upon
+Ottoman architecture published in Constantinople under the patronage of
+Edhem Pasha. The pomegranate that has served as the original of the pattern
+in question is in this work surrounded with leaves till it gives some sort
+of an approach to the pattern. (There are important suggestions in the book
+as to the employment of melon-forms.) Whoever has picked the fruit from the
+tender twigs of the pomegranate tree, which are close set with small
+altered leaves, will never dream of attributing the derivation of the
+thorny leaves that appear in the pattern to pomegranate leaves at any stage
+of their development.
+
+[Illustration: FIG. 14]
+
+It does not require much penetration to see that the outline of the whole
+form corresponds to the spathe of the Araceae, even although in later times
+the jagged contour is all that has remained of it, and it appears to have
+been provided with ornamental forms quite independently of the rest of the
+pattern. The inner thistle-form cannot be derived from the common thistle,
+because the surrounding leaves negative any such idea. The artichoke theory
+also has not enough in its favor, although the artichoke, as well as the
+thistle, was probably at a later time directly pressed into service. Prof.
+Ascherson first called my attention to the extremely anciently cultivated
+plant, the safflor (_Carthamus tinctoris_, Fig. 15), a thistle plant whose
+flowers were employed by the ancients as a dye. Some drawings and dried
+specimens, as well as the literature of the subject, first gave me a hope
+to find that this plant was the archetype of this ornament, a hope that was
+borne out by the study of the actual plant, although I was unable to grow
+it to any great perfection.
+
+In the days of the Egyptian King Sargo (according to Ascherson and
+Schweinfurth) this plant was already well known as a plant of cultivation;
+in a wild state it is not known (De Candolle, "Originel des Plantes
+cultivees"). In Asia its cultivation stretches to Japan. Semper cites a
+passage from an Indian drama to the effect that over the doorway there was
+stretched an arch of ivory, and about it were bannerets on which wild
+safran (_Saflor_) was painted.
+
+[Illustration: FIG. 15]
+
+The importance of the plant as a dye began steadily to decrease, and it has
+now ceased to have any value as such in the face of the introduction of
+newer coloring matters (a question that was treated of in a paper read a
+short time ago by Dr. Reimann before this Society). Perhaps its only use
+nowadays is in the preparation of rouge (_rouge vegetale_).
+
+But at a time when dyeing, spinning, and weaving were, if not in the one
+hand, yet at any rate intimately connected with one another in the narrow
+circle of a home industry, the appearance of this beautiful gold-yellow
+plant, heaped up in large masses, would be very likely to suggest its
+immortalization in textile art, because the drawing is very faithful to
+nature in regard to the thorny involucre. Drawings from nature of the plant
+in the old botanical works of the sixteenth and seventeenth centuries look
+very like ornamental patterns. Now after the general form had been
+introduced, pomegranates or other fruits--for instance, pine-apples--were
+introduced within the nest of leaves.
+
+[Illustration: FIG. 16.]
+
+Into the detailed study of the intricacies of this subject I cannot here
+enter; the East-Asian influences are not to be neglected, which had
+probably even in early times an effect upon the form that was assumed, and
+have fused the correct style of compound flowers for flat ornament with the
+above-mentioned forms, so as to produce peculiar patterns; we meet them
+often in the so-called Persian textures and flat ornaments (Fig. 16).
+
+We now come to the third group of forms--the so-called Cashmere pattern, or
+Indian palmetta. The developed forms, which, when they have attained their
+highest development, often show us outlines that are merely fanciful, and
+represent quite a bouquet of flowers leaning over to one side, and
+springing from a vessel (the whole corresponding to the Roman form with the
+vessel), must be thrown to one side, while we follow up the simpler forms,
+because in this case also we have no information as to either the where or
+the when the forms originated. (Figs. 17, 18, 19.)
+
+[Illustration: FIG. 17.]
+
+Here again we are struck by resemblances to the forms that were the
+subjects of our previous study, we even come across direct transitional
+forms, which differ from the others only by the lateral curve of the apex
+of the leaf; sometimes it is the central part, the spadix, that is bent
+outward, and the very details show a striking agreement with the structure
+of the aroid inflorescence, so much so that one might regard them as
+actually copied from them.
+
+[Illustration: FIG. 18.]
+
+This form of ornament has been introduced into Europe since the French
+expedition to Egypt, owing to the importation of genuine Cashmere shawls.
+(When it cropped up in isolated forms, as in Venice in the fifteenth
+century, it appears not to have exerted any influence; its introduction is
+perhaps rather to be attributed to calico-printing.) Soon afterward the
+European shawl-manufacture, which is still in a flourishing state, was
+introduced. Falcot informs us that designs of a celebrated French artist,
+Couder, for shawl-patterns, a subject that he studied in India itself, were
+exported back to that country and used there (Fig. 20).
+
+In these shawl-patterns the original simple form meets us in a highly
+developed, magnificent, and splendidly colored differentiation and
+elaboration. This we can have no scruples in ranking along with the
+mediaeval plane-patterns, which we have referred to above, among the highest
+achievements of decorative art.
+
+[Illustration: FIG. 19.]
+
+It is evident that it, at any rate in this high stage of development,
+resisted fusion with Western forms of art. It is all the more incumbent
+upon us to investigate the laws of its existence, in order to make it less
+alien to us, or perhaps to assimilate it to ourselves by attaining to an
+understanding of those laws. A great step has been made when criticism has,
+by a more painstaking study, put itself into a position to characterize as
+worthless ignorantly imitated, or even original, miscreations such as are
+eternally cropping up. If we look at our modern manufactures immediately
+after studying patterns which enchant us with their classical repose, or
+after it such others as captivate the eye by their beautiful coloring, or
+the elaborative working out of their details, we recognize that the
+beautifully balanced form is often cut up, choked over with others, or
+mangled (the flower springing up side down from the leaves), the whole
+being traversed at random by spirals, which are utterly foreign to the
+spirit of such a style, and all this at the caprice of uncultured, boorish
+designers. Once we see that the original of the form was a plant, we shall
+ever in the developed, artistic form cling, in a general way at least, to
+the laws of its organization, and we shall at any rate be in a position to
+avoid violent incongruities.
+
+[Illustration: FIG. 20.]
+
+I had resort, a few years ago, to the young botanist Ruhmer, assistant at
+the Botanical Museum at Schoeneberg, who has unfortunately since died of
+some chest-disease, in order to get some sort of a groundwork for direct
+investigations. I asked him to look up the literature of the subject, with
+respect to the employment of the Indian Araceae for domestic uses or in
+medicine. A detailed work on the subject was produced, and establishes
+that, quite irrespective of species of Alocasia and Colocasia that have
+been referred to, a large number of Araceae were employed for all sorts of
+domestic purposes. Scindapsus, which was used as a medicine, has actually
+retained a Sanskrit name, "vustiva." I cannot here go further into the
+details of this investigation, but must remark that even the incomplete and
+imperfect drawings of these plants, which, owing to the difficulty of
+preserving them, are so difficult to collect through travelers, exhibit
+such a wealth of shape, that it is quite natural that Indian and Persian
+flower-loving artists should be quite taken with them, and employ them
+enthusiastically in decorative art. Let me also mention that Haeckel, in
+his '"Letters of an Indian Traveler," very often bears witness to the
+effect of the Araceae upon the general appearance of the vegetation, both in
+the full and enormous development of species of Caladia and in the species
+of Pothos which form such impenetrable mazes of interlooping stems.
+
+In conclusion, allow me to remark that the results of my investigation, of
+which but a succinct account has been given here, negative certain
+derivations, which have been believed in, though they have never been
+proved; such as that of the form I have last discussed from the Assyrian
+palmetta, or from a cypress bent down by the wind. To say the least the
+laws of formation here laid down have a more intimate connection with the
+forms as they have come down to us, and give us a better handle for future
+use and development. The object of the investigation was, in general words,
+to prepare for an explanation of the questions raised; and even if the
+results had turned out other than they have, it would have sufficed me to
+have given an impulse to labors which will testify to the truth of the dead
+master's words:
+
+    "Was Du ererbt von deinen Vaetern hast,
+    Erwirb es, um es zu besitzen."
+
+       *       *       *       *       *
+
+
+
+
+STEPS TOWARD A KINETIC THEORY OF MATTER.
+
+[Footnote: Meeting of the British Association, Montreal. 1884. Section A.
+Mathematical and Physical science. Opening Address by Prof. Sir William
+Thomson, M.A., LL.D., D.C.L., F.R.SS.L. and E., F.R.A.S., President of the
+Section.]
+
+By Sir WILLIAM THOMSON.
+
+
+The now well known kinetic theory of gases is a step so important in the
+way of explaining seemingly static properties of matter by motion, that it
+is scarcely possible to help anticipating in idea the arrival at a complete
+theory of matter, in which all its properties will be seen to be merely
+attributes of motion. If we are to look for the origin of this idea we must
+go back to Democritus, Epicurus, and Lucretius. We may then, I believe,
+without missing a single step, skip 1800 years. Early last century we find
+in Malebranche's "Recherche de la Verite," the statement that "la durete de
+corps" depends on "petits tourbillons." [1] These words, embedded in a
+hopeless mass of unintelligible statements of the physical, metaphysical,
+and theological philosophies of the day, and unsupported by any
+explanation, elucidation, or illustration throughout the rest of the three
+volumes, and only marred by any other single sentence or word to be found
+in the great book, still do express a distinct conception which forms a
+most remarkable step toward the kinetic theory of matter. A little later we
+have Daniel Bernoulli's promulgation of what we now accept as a surest
+article of scientific faith--the kinetic theory of gases. He, so far as I
+know, thought only of Boyle's and Mariotte's law of the "spring of air," as
+Boyle called it, without reference to change of temperature or the
+augmentation of its pressure if not allowed to expand for elevation of
+temperature, a phenomenon which perhaps he scarcely knew, still less the
+elevation of temperature produced by compression, and the lowering of
+temperature by dilatation, and the consequent necessity of waiting for a
+fraction of a second or a few seconds of time (with apparatus of ordinary
+experimental magnitude), to see a subsidence from a larger change of
+pressure down to the amount of change that verifies Boyle's law. The
+consideration of these phenomena forty years ago by Joule, in connection
+with Bernoulli's original conception, formed the foundation of the kinetic
+theory of gases as we now have it. But what a splendid and useful building
+has been placed on this foundation by Clausius and Maxwell, and what a
+beautiful ornament we see on the top of it in the radiometer of Crookes,
+securely attached to it by the happy discovery of Tait and Dewar,[2] that
+the length of the free path of the residual molecules of air in a good
+modern vacuum may amount to several inches! Clausius' and Maxwell's
+explanations of the diffusion of gases, and of thermal conduction in gases,
+their charmingly intelligible conclusion that in gases the diffusion of
+heat is just a little more rapid than the diffusion of molecules, because
+of the interchange of energy in collisions between molecules,[3] while the
+chief transference of heat is by actual transport of the molecules
+themselves, and Maxwell's explanation of the viscosity of gases, with the
+absolute numerical relations which the work of those two great discoverers
+found among the three properties of diffusion, thermal conduction, and
+viscosity, have annexed to the domain of science a vast and ever growing
+province.
+
+[Footnote 1: "Preuve de la supposition que j'ay faite: Que la matiere
+subtile ou etheree est necessairement composee de PETITS TOURBILLONS; et
+qu'ils sont les causes naturelles de tous les changements qui arrivent a la
+matiere; ce que je confirme par i'explication des effets les plus generaux
+de la Physique, tels que sont la durete des corps, leur fluidite, leur
+pesanteur, legerete, la lumiere et la refraction et reflexion de ses
+rayons."--Malebranche, "Recherche de la Verite," 1712.]
+
+[Footnote 2: Proc. R.S.E., March 2, 1874, and July 5, 1875.]
+
+[Footnote 3: On the other hand, in liquids, on account of the crowdedness
+of the molecules, the diffusion of heat must be chiefly by interchange of
+energies between the molecules, and should be, as experiment proves it is,
+enormously more rapid than the diffusion of the molecules themselves, and
+this again ought to be much less rapid than either the material or thermal
+diffusivities of gases. Thus the diffusivity of common salt through water
+was found by Fick to be as small as 0.0000112 square centimeter per second;
+nearly 200 times as great as this is the diffusivity of heat through water,
+which was found by J.T. Bottomley to be about 0.002 square centimeter per
+second. The material diffusivities of gases, according to Loschmidt's
+experiments, range from 0.98 (the interdiffusivity of carbonic acid and
+nitrous oxide) to 0.642 (the interdiffusivity of carbonic oxide and
+hydrogen), while the thermal diffusivities of gases, calculated according
+to Clausius' and Maxwell's kinetic theory of gases, are 0.089 for carbonic
+acid, 0.16 for common air of other gases of nearly the same density, and
+1.12 for hydrogen (all, both material and thermal, being reckoned in square
+centimeters per second).]
+
+Rich as it is in practical results, the kinetic theory of gases, as
+hitherto developed, stops absolutely short at the atom or molecule, and
+gives not even a suggestion toward explaining the properties in virtue of
+which the atoms or molecules mutually influence one another. For some
+guidance toward a deeper and more comprehensive theory of matter, we may
+look back with advantage to the end of last century and beginning of this
+century, and find Rumford's conclusion regarding the heat generated in
+boring a brass gun: "It appears to me to be extremely difficult, if not
+quite impossible, to form any distinct idea of anything capable of being
+excited and communicated in the manner the heat was excited and
+communicated in these experiments, except it be MOTION;" and Davy's still
+more suggestive statements: "The phenomena of repulsion are not dependent
+on a peculiar elastic fluid for their existence." ... "Heat may be defined
+as a peculiar motion, probably a vibration, of the corpuscles of bodies,
+tending to separate them." ... "To distinguish this motion from others, and
+to signify the causes of our sensations of heat, etc., the name _repulsive_
+motion has been adopted." Here we have a most important idea. It would be
+somewhat a bold figure of speech to say the earth and moon are kept apart
+by a repulsive motion; and yet, after all, what is centrifugal force but a
+repulsive motion, and may it not be that there is no such thing as
+repulsion, and that it is solely by inertia that what seems to be repulsion
+is produced? Two bodies fly together, and, accelerated by mutual
+attraction, if they do not precisely hit one another, they cannot but
+separate in virtue of the inertia of their masses. So, after dashing past
+one another in sharply concave curves round their common center of gravity,
+they fly asunder again. A careless onlooker might imagine they had repelled
+one another, and might not notice the difference between what he actually
+sees and what he would see if the two bodies had been projected with great
+velocity toward one another, and either colliding and rebounding, or
+repelling one another into sharply convex continuous curves, fly asunder
+again.
+
+Joule, Clausius, and Maxwell, and no doubt Daniel Bernoulli himself, and I
+believe every one who has hitherto written or done anything very explicit
+in the kinetic theory of gases, has taken the mutual action of molecules in
+collision as repulsive. May it not after all be attractive? This idea has
+never left my mind since I first read Davy's "Repulsive Motion," about
+thirty-five years ago, and I never made anything of it, at all events have
+not done so until to-day (June 16, 1884)--if this can be said to be making
+anything of it--when, in endeavoring to prepare the present address, I
+notice that Joule's and my own old experiments[1] on the thermal effect of
+gases expanding from a high-pressure vessel through a porous plug, proves
+the less dense gas to have greater intrinsic _potential_ energy than the
+denser gas, if we assume the ordinary hypothesis regarding the temperature
+of a gas, according to which two gases are of equal temperatures [2] when
+the kinetic energies of their constituent molecules are of equal average
+amounts per molecule.
+
+[Footnote 1: Republished in Sir W. Thomson's "Mathematical and Physical
+Papers," vol. i., article xlix., p. 381. ]
+
+[Footnote 2: That this is a mere hypothesis has been scarcely remarked by
+the founders themselves, nor by almost any writer on the kinetic theory of
+gases. No one has yet examined the question, What is the condition as
+regards average distribution of kinetic energy, which is ultimately
+fulfilled by two portions of gaseous matter, separated by a thin elastic
+septum which absolutely prevents interdiffusion of matter, while it allows
+interchange of kinetic energy by collisions against itself? Indeed, I do
+not know but, that the present is the very first statement which has ever
+been published of this condition of the problem of equal temperatures
+between two gaseous masses.]
+
+Think of the thing thus. Imagine a great multitude of particles inclosed by
+a boundary which may be pushed inward in any part all round at pleasure.
+Now station an engineer corps of Maxwell's army of sorting demons all round
+the inclosure, with orders to push in the boundary diligently everywhere,
+when none of the besieged troops are near, and to do nothing when any of
+them are seen approaching, and until after they have turned again inward.
+The result will be that, with exactly the same sum of kinetic and potential
+energies of the same inclosed multitude of particles, the throng has been
+caused to be denser. Now Joule's and my own old experiments on the efflux
+of air prove that if the crowd be common air, or oxygen, or nitrogen, or
+carbonic acid, the temperature is a little higher in the denser than in the
+rarer condition when the energies are the same. By the hypothesis, equality
+of temperature between two different gases or two portions of the same gas
+at different densities means equality of kinetic energies in the same
+number of molecules of the two. From our observations proving the
+temperature to be higher, it therefore follows that the potential energy is
+smaller in the condensed crowd. This--always, however, under protest as to
+the temperature hypothesis--proves some degree of attraction among the
+molecules, but it does not prove ultimate attraction between two molecules
+in collision, or at distances much less than the average mutual distance of
+nearest neighbors in the multitude. The collisional force might be
+repulsive, as generally supposed hitherto, and yet attraction might
+predominate in the whole reckoning of difference between the intrinsic
+potential energies of the more dense and less dense multitudes.
+
+It is however remarkable that the explanation of the propagation of sound
+through gases, and even of the positive fluid pressure of a gas against the
+sides of the containing vessel, according to the kinetic theory of gases,
+is quite independent of the question whether the ultimate collisional force
+is attractive or repulsive. Of course it must be understood that, if it is
+attractive, the particles must, be so small that they hardly ever
+meet--they would have to be infinitely small to _never_ meet--that, in
+fact, they meet so seldom, in comparison with the number of times their
+courses--are turned through large angles by attraction, that the influence
+of these surely attractive collisions is preponderant over that of the
+comparatively very rare impacts from actual contact. Thus, after all, the
+train of speculation suggested by Davy's "Repulsive Motion" does not allow
+us to escape from the idea of true repulsion, does not do more than let us
+say it is of no consequence, nor even say this with truth, because, if
+there are impacts at all, the nature of the force during the impact and the
+effects of the mutual impacts, however rare, cannot be evaded in any
+attempt to realize a conception of the kinetic theory of gases. And in
+fact, unless we are satisfied to imagine the atoms of a gas as mathematical
+points endowed with inertia, and as, according to Boscovich, endowed with
+forces of mutual, positive, and negative attraction, varying according to
+some definite function of the distance, we cannot avoid the question of
+impacts, and of vibrations and rotations of the molecules resulting from
+impacts, and we must look distinctly on each molecule as being either a
+little elastic solid or a configuration of motion in a continuous
+all-pervading liquid. I do not myself see how we can ever permanently rest
+anywhere short of this last view; but it would be a very pleasant temporary
+resting-place on the way to it if we could, as it were, make a mechanical
+model of a gas out of little pieces of round, perfectly elastic solid
+matter, flying about through the space occupied by the gas, and colliding
+with one another and against the sides of the containing vessel.
+
+This is, in fact, all we have of the kinetic theory of gases up to the
+present time, and this has done for us, in the hands of Clausius and
+Maxwell, the great things which constitute our first step toward a
+molecular theory of matter. Of course from it we should have to go on to
+find an explanation of the elasticity and all the other properties of the
+molecules themselves, a subject vastly more complex and difficult than the
+gaseous properties, for the explanation of which we assume the elastic
+molecule; but without any explanation of the properties of the molecule
+itself, with merely the assumption that the molecule has the requisite
+properties, we might rest happy for a while in the contemplation of the
+kinetic theory of gases, and its explanation of the gaseous properties,
+which is not only stupendously important as a step toward a more
+thoroughgoing theory of matter, but is undoubtedly the expression of a
+perfectly intelligible and definite set of facts in Nature.
+
+But alas for our mechanical model consisting of the cloud of little elastic
+solids flying about among one another. Though each particle have absolutely
+perfect elasticity, the end must be pretty much the same as if it were but
+imperfectly elastic. The average effect of repeated and repeated mutual
+collisions must be to gradually convert all the translational energy into
+energy of shriller and shriller vibrations of the molecule. It seems
+certain that each collision must have something more of energy in
+vibrations of very finely divided nodal parts than there was of energy in
+such vibrations before the impact. The more minute this nodal subdivision,
+the less must be the tendency to give up part of the vibrational energy
+into the shape of translational energy in the course of a collision; and I
+think it is rigorously demonstrable that the whole translational energy
+must ultimately become transformed into vibrational energy of higher and
+higher nodal subdivisions if each molecule is a continuous elastic solid.
+Let us, then, leave the kinetic theory of gases for a time with this
+difficulty unsolved, in the hope that we or others after us may return to
+it, armed with more knowledge of the properties of matter, and with sharper
+mathematical weapons to cut through the barrier which at present hides from
+us any view of the molecule itself, and of the effects other than mere
+change of translational motion which it experiences in collision.
+
+To explain the elasticity of a gas was the primary object of the kinetic
+theory of gases. This object is only attainable by the assumption of an
+elasticity more complex in character, and more difficult of explanation,
+than the elasticity of gases--the elasticity of a solid. Thus, even if the
+fatal fault in the theory, to which I have alluded, did not exist, and if
+we could be perfectly satisfied with the kinetic theory of gases founded on
+the collisions of elastic solid molecules, there would still be beyond it a
+grander theory which need not be considered a chimerical object of
+scientific ambition--to explain the elasticity of solids. But we may be
+stopped when we commence to look in the direction of such a theory with the
+cynical question, What do you mean by explaining a property of matter? As
+to being stopped by any such question, all I can say is that if engineering
+were to be all and to end all physical science, we should perforce be
+content with merely finding properties of matter by observation, and using
+them for practical purposes. But I am sure very few, if any, engineers are
+practically satisfied with so narrow a view of their noble profession. They
+must and do patiently observe, and discover by observation, properties of
+matter and results of material combinations. But deeper questions are
+always present, and always fraught with interest to the true engineer, and
+he will be the last to give weight to any other objection to any attempt to
+see below the surface of things than the practical question, Is it likely
+to prove wholly futile? But now, instead of imagining the question, What do
+you mean by explaining a property of matter? to be put cynically, and
+letting ourselves be irritated by it, suppose we give to the questioner
+credit for being sympathetic, and condescend to try and answer his
+question. We find it not very easy to do so. All the properties of matter
+are so connected that we can scarcely imagine one _thoroughly explained_
+without our seeing its relation to all the others, without in fact having
+the explanation of all; and till we have this we cannot tell what we mean
+by "explaining a property" or "explaining the properties" of matter. But
+though this consummation may never be reached by man, the progress of
+science may be, I believe will be, step by step toward it, on many
+different roads converging toward it from all sides. The kinetic theory of
+gases is, as I have said, a true step on one of the roads. On the very
+distinct road of chemical science, St. Claire Deville arrived at his grand
+theory of dissociation without the slightest aid from the kinetic theory of
+gases. The fact that he worked it out solely from chemical observation and
+experiment, and expounded it to the world without any hypothesis whatever,
+and seemingly even without consciousness of the beautiful explanation it
+has in the kinetic theory of gases, secured for it immediately an
+independent solidity and importance as a chemical theory when he first
+promulgated it, to which it might even by this time scarcely have attained
+if it had first been suggested as a probability indicated by the kinetic
+theory of gases, and been only afterward confirmed by observation. Now,
+however, guided by the views which Clausius and Williamson have given us of
+the continuous interchange of partners between the compound molecules
+constituting chemical compounds in the gaseous state, we see in Deville's
+theory of dissociation a point of contact of the most transcendent interest
+between the chemical and physical lines of scientific progress.
+
+To return to elasticity: if we could make out of matter devoid of
+elasticity a combined system of relatively moving parts which, in virtue of
+motion, has the essential characteristics of an elastic body, this would
+surely be, if not positively a step in the kinetic theory of matter, at
+least a fingerpost pointing a way which we may hope will lead to a kinetic
+theory of matter. Now this, as I have already shown,[1] we can do in
+several ways. In the case of the last of the communications referred to, of
+which only the title has hitherto been published, I showed that, from the
+mathematical investigation of a gyrostatically dominated combination
+contained in the passage of Thomson and Tait's "Natural Philosophy"
+referred to, it follows that any ideal system of material particles, acting
+on one another mutually through massless connecting springs, may be
+perfectly imitated in a model consisting of rigid links jointed together,
+and having rapidly rotating fly wheels pivoted on some or on all of the
+links. The imitation is not confined to cases of equilibrium. It holds also
+for vibration produced by disturbing the system infinitesimally from a
+position of stable equilibrium and leaving it to itself. Thus we may make a
+gyrostatic system such that it is in equilibrium under the influence of
+certain positive forces applied to different points of this system; all the
+forces being precisely the same as, and the points of application similarly
+situated to, those of the stable system with springs. Then, provided proper
+masses (that is to say, proper amounts and distributions of inertia) be
+attributed to the links, we may remove the external forces from each
+system, and the consequent vibration of the points of application of the
+forces will be identical. Or we may act upon the systems of material points
+and springs with any given forces for any given time, and leave it to
+itself, and do the same thing for the gyrostatic system; the consequent
+motion will be the same in the two cases. If in the one case the springs
+are made more and more stiff, and in the other case the angular velocities
+of the fly wheels are made greater and greater, the periods of the
+vibrational constituents of the motion will become shorter and shorter, and
+the amplitudes smaller and smaller, and the motions will approach more and
+more nearly those of two perfectly rigid groups of material points moving
+through space and rotating according to the well known mode of rotation of
+a rigid body having unequal moments of inertia about its three principal
+axes. In one case the ideal nearly rigid connection between the particles
+is produced by massless, exceedingly stiff springs; in the other case it is
+produced by the exceedingly rapid rotation of the fly wheels in a system
+which, when the fly wheels are deprived of their rotation, is perfectly
+limp.
+
+[Footnote 1: Paper on "Vortex Atoms," _Proc_. R.S.E. February. 1867:
+abstract of a lecture before the Royal Institution of Great Britain, March
+4, 1881, on "Elasticity Viewed as possibly a Mode of Motion"; Thomson and
+Tait's "Natural Philosophy," second edition, part 1, Sec.Sec. 345 viii. to 345
+xxxvii.; "On Oscillation and Waves in an Adynamic Gyrostatic System" (title
+only), _Proc_. R.S.E. March, 1883.]
+
+The drawings (Figs. 1 and 2) before you illustrate two such material
+systems.[1] The directions of rotation of the fly-wheels in the gyrostatic
+system (Fig. 2) are indicated by directional ellipses, which show in
+perspective the direction of rotation of the fly-wheel of each gyrostat.
+The gyrostatic system (Fig. 2) might have been constituted of two
+gyrostatic members, but four are shown for symmetry. The inclosing circle
+represents in each case in section an inclosing spherical shell to prevent
+the interior from being seen. In the inside of one there are fly-wheels, in
+the inside of the other a massless spring. The projecting hooked rods seem
+as if they are connected by a spring in each case. If we hang any one of
+the systems up by the hook on one of its projecting rods, and hang a weight
+to the hook of the other projecting rod, the weight, when first put on,
+will oscillate up and down, and will go on doing so for ever if the system
+be absolutely unfrictional. If we check the vibration by hand, the weight
+will hang down at rest, the pin drawn out to a certain degree; and the
+distance drawn out will be simply proportional to the weight hung on, as in
+an ordinary spring balance.
+
+[Footnote 1: In Fig. 1 the two hooked rods seen projecting from the sphere
+are connected by an elastic coach-spring. In Fig. 2 the hooked rods are
+connected one to each of two opposite corners of a four-sided jointed
+frame, each member of which carries a gyrostat so that the axis of rotation
+of the fly-wheel is in the axis of the member of the frame which bears it.
+Each of the hooked rods in Fig. 2 is connected to the framework through a
+swivel joint, so that the whole gyrostatic framework may be rotated about
+the axis of the hooked rods in order to annul the moment of momentum of the
+framework about this axis due to rotation of the fly-wheels in the
+gyrostat.]
+
+[Illustration: FIG. 1]
+
+[Illustration: FIG. 2]
+
+Here, then, out of matter possessing rigidity, but absolutely devoid of
+elasticity, we have made a perfect model of a spring in the form of a
+spring balance. Connect millions of millions of particles by pairs of rods
+such as these of this spring balance, and we have a group of particles
+constituting an elastic solid; exactly fulfilling the mathematical ideal
+worked out by Navier, Poisson, and Cauchy, and many other mathematicians,
+who, following their example, have endeavored to found a theory of the
+elasticity of solids on mutual attraction and repulsion between a group of
+material particles. All that can possibly be done by this theory, with its
+assumption of forces acting according to any assumed law of relation to
+distance, is done by the gyrostatic system. But the gyrostatic system does,
+besides, what the system of naturally acting material particles cannot
+do--it constitutes an elastic solid which can have the Faraday
+magneto-optic rotation of the plane of polarization of light; supposing the
+application of our solid to be a model of the luminiferous ether for
+illustrating the undulatory theory of light. The gyrostatic model spring
+balance is arranged to have zero moment of momentum as a whole, and
+therefore to contribute nothing to the Faraday rotation; with this
+arrangement the model illustrates the luminiferous ether in a field
+unaffected by magnetic force. But now let there be a different rotational
+velocity imparted to the jointed square round the axis of the two
+projecting hooked rods, such as to give a resultant moment of momentum
+round any given line through the center of inertia of the system; and let
+pairs of the hooked rods in the model thus altered, which is no longer a
+model of a mere spring balance, be applied as connections between millions
+of pairs of particles as before, with the lines of resultant moment of
+momentum all similarly directed. We now have a model elastic solid which
+will have the property that the direction of vibration in waves of
+rectilinear vibrations propagated through it shall turn round the line of
+propagation of the waves, just as Faraday's observation proves to be done
+by the line of vibration of light in a dense medium between the poles of a
+powerful magnet. The case of wave front perpendicular to the lines of
+resultant moment of momentum (that is to say, the direction of propagation
+being parallel to these lines) corresponds, in our mechanical model, to the
+case of light traveling in the direction of the lines of force in a
+magnetic field.
+
+In these illustrations and models we have different portions of ideal rigid
+matter acting upon one another, by normal pressure at mathematical points
+of contact--of course no forces of friction are supposed. It is exceedingly
+interesting to see how thus, with no other postulates than inertia,
+rigidity, and mutual impenetrability, we can thoroughly model not only an
+elastic solid, and any combination of elastic solids, but so complex and
+recondite a phenomenon as the passage of polarized light through a magnetic
+field. But now, with the view of ultimately discarding the postulate of
+rigidity from all our materials, let us suppose some to be absolutely
+destitute of rigidity, and to possess merely inertia and incompressibility,
+and mutual impenetrability with reference to the still remaining rigid
+matter. With these postulates we can produce a perfect model of mutual
+action at a distance between solid particles, fulfilling the condition, so
+keenly desired by Newton and Faraday, of being explained by continuous
+action through an intervening medium. The law of the mutual force in our
+model, however, is not the simple Newtonian law, but the much more complex
+law of the mutual action between electro magnets--with this difference,
+that in the hydro-kinetic model in every case the force is opposite in
+direction to the corresponding force in the electro-magnetic analogue.
+Imagine a solid bored through with a hole, and placed in our ideal perfect
+liquid. For a moment let the hole be stopped by a diaphragm, and let an
+impulsure pressure be applied for an instant uniformly over the whole
+membrane, and then instantly let the membrane be dissolved into liquid.
+This action originates a motion of the liquid relatively to the solid, of a
+kind to which I have given the name of "irrotational circulation," which
+remains absolutely constant however the solid be moved through the liquid.
+Thus, at any time the actual motion of the liquid at any point in the
+neighborhood of the solid will be the resultant of the motion it would have
+in virtue of the circulation alone, were the solid at rest, and the motion
+it would have in virtue of the motion of the solid itself, had there been
+no circulation established through the aperture. It is interesting and
+important to remark in passing that the whole kinetic energy of the liquid
+is the sum of the kinetic energies which it would have in the two cases
+separately. Now, imagine the whole liquid to be inclosed in an infinitely
+large, rigid, containing vessel, and in the liquid, at an infinite distance
+from any part of the containing vessel, let two perforated solids, with
+irrotational circulation through each, be placed at rest near one another.
+The resultant fluid motion due to the two circulations, will give rise to
+fluid pressure on the two bodies, which, if unbalanced, will cause them to
+move. The force systems--force-and-torques, or pairs of forces--required to
+prevent them from moving will be mutual and opposite, and will be the same
+as, but opposite in direction to, the mutual force systems required to hold
+at rest two electromagnets fulfilling the following specification: The two
+electro magnets are to be of the same shape and size as the two bodies, and
+to be placed in the same relative positions, and to consist of infinitely
+thin layers of electric currents in the surfaces of solids possessing
+extreme diamagnetic quality--in other words, infinitely small permeability.
+The distribution of electric current on each body may be any whatever which
+fulfills the condition that the total current across any closed line drawn
+on the surface once through the aperture is equal to 1/4 [pi] of the
+circulation[1] through the aperture in the hydro-kinetic analogue.
+
+[Footnote 1: The integral of tangential component velocity all round any
+closed curve, passing once through the aperture, is defined as the
+"cyclic-constant" or the "circulation" ("Vortex Motion," Sec. 60 (a), _Trans_.
+R.S.E., April 29, 1867). It has the same value for all closed curves
+passing just once through the aperture, and it remains constant through all
+time, whether the solid body be in motion or at rest.]
+
+It might be imagined that the action at a distance thus provided for by
+fluid motion could serve as a foundation for a theory of the equilibrium,
+and the vibrations, of elastic solids, and the transmission of waves like
+those of light through an extended quasi-elastic solid medium. But
+unfortunately for this idea the equilibrium is essentially unstable, both
+in the case of magnets and, notwithstanding the fact that the forces are
+oppositely directed, in the hydro-kinetic analogue also, when the several
+movable bodies (two or any greater number) are so placed relatively as to
+be in equilibrium. If, however, we connect the perforated bodies with
+circulation through them in the hydro-kinetic system, by jointed rigid
+connecting links, we may arrange for configurations of stable equilibrium.
+Thus, without fly-wheels, but with fluid circulations through apertures, we
+may make a model spring balance or a model luminiferous ether, either
+without or with the rotational quality corresponding to that of the true
+luminiferous ether in the magnetic fluid--in short, do all by the
+perforated solids with circulations through them that we saw we could do by
+means of linked gyrostats. But something that we cannot do by linked
+gyrostats we can do by the perforated bodies with fluid circulation: we can
+make a model gas. The mutual action at a distance, repulsive or attractive
+according to the mutual aspect of the two bodies when passing within
+collisional distance[1] of one another, suffices to produce the change of
+direction of motion in collision, which essentially constitutes the
+foundation of the kinetic theory of gases, and which, as we have seen
+before, may as well be due to attraction as to repulsion, so far as we know
+from any investigation hitherto made in this theory.
+
+[Footnote 1: According to this view, there is no precise distance, or
+definite condition respecting the distance, between two molecules, at which
+apparently they come to be in collision, or when receding from one another
+they cease to be in collision. It is convenient, however, in the kinetic
+theory of gases, to adopt arbitrarily a precise definition of collision,
+according to which two bodies or particles mutually acting at a distance
+may be said to be in collision when their mutual action exceeds some
+definite arbitrarily assigned limit, as, for example, when the radius of
+curvature of the path of either body is less than a stated fraction (one
+one-hundredth, for instance) of the distance between them.]
+
+There remains, however, as we have seen before, the difficulty of providing
+for the case of actual impacts between the solids, which must be done by
+giving them massless spring buffers or, which amounts to the same thing,
+attributing to them repulsive forces sufficiently powerful at very short
+distances to absolutely prevent impacts between solid and solid; unless we
+adopt the equally repugnant idea of infinitely small perforated solids,
+with infinitely great fluid circulations through them. Were it not for this
+fundamental difficulty, the hydro-kinetic model gas would be exceedingly
+interesting; and, though we could scarcely adopt it as conceivably a true
+representation of what gases really are, it might still have some
+importance as a model configuration of solid and liquid matter, by which
+without elasticity the elasticity of true gas might be represented.
+
+But lastly, since the hydro-kinetic model gas with perforated solids and
+fluid circulations through them fails because of the impacts between the
+solids, let us annul the solids and leave the liquid performing
+irrotational circulation round vacancy,[1] in the place of the solid cores
+which we have hitherto supposed; or let us annul the rigidity of the solid
+cores of the rings, and give them molecular rotation according to
+Helmholtz's theory of vortex motion. For stability the molecular rotation
+must be such as to give the same velocity at the boundary of the rotational
+fluid core as that of the irrotationally circulating liquid in contact with
+it, because, as I have proved, frictional slip between two portions of
+liquid in contact is inconsistent with stability. There is a further
+condition, upon which I cannot enter into detail just now, but which may be
+understood in a general way when I say that it is a condition of either
+uniform or of increasing molecular rotation from the surface inward,
+analogous to the condition that the density of a liquid, resting for
+example under the influence of gravity, must either be uniform or must be
+greater below than above for stability of equilibrium. All that I have said
+in favor of the model vortex gas composed of perforated solids with fluid
+circulations through them holds without modification for the purely
+hydro-kinetic model, composed of either Helmholtz cored vortex rings or of
+coreless vortices, and we are now troubled with no such difficulty as that
+of the impacts between solids. Whether, however, when the vortex theory of
+gases is thoroughly worked out, it will or will not be found to fail in a
+manner analogous to the failure which I have already pointed out in
+connection with the kinetic theory of gases composed of little elastic
+solid molecules, I cannot at present undertake to speak with certainty. It
+seems to me most probable that the vortex theory cannot fail in any such
+way, because all I have been able to find out hitherto regarding the
+vibration of vortices,[2] whether cored or coreless, does not seem to imply
+the liability of translational or impulsive energies of the individual
+vortices becoming lost in energy of smaller and smaller vibrations.
+
+[Footnote 1: Investigations respecting coreless vortices will be found in a
+paper by the author, "Vibrations of a Columnar Vortex," _Proc_. R.S.E.,
+March 1, 1880; and a paper by Hicks, recently read before the Royal
+Society.]
+
+[Footnote 2: See papers by the author "On Vortex Motion." _Trans_. R.S.E.
+April, 1867, and "Vortex Statics," _Proc_. R.S.E. December, 1875; also a
+paper by J.J. Thomson, B.A., "On the Vibrations of a Vortex Ring," _Trans_.
+R.S. December, 1881, and his valuable book on "Vortex Motion."]
+
+As a step toward kinetic theory of matter, it is certainly most interesting
+to remark that in the quasi-elasticity, elasticity looking like that of an
+India-rubber band, which we see in a vibrating smoke-ring launched from an
+elliptic aperture, or in two smoke-rings which were circular, but which
+have become deformed from circularity by mutual collision, we have in
+reality a virtual elasticity in matter devoid of elasticity, and even
+devoid of rigidity, the virtual elasticity being due to motion, and
+generated by the generation of motion.
+
+       *       *       *       *       *
+
+
+
+
+APPLICATION OF ELECTRICITY TO TRAMWAYS.
+
+By M. HOLROYD SMITH.
+
+
+Last year, when I had the pleasure of reading a paper before you on my new
+system of electric tramways, I ventured to express the hope that before
+twelve months had passed, "to be able to report progress," and I am happy
+to say that notwithstanding the wearisome delay and time lost in fruitless
+negotiations, and the hundred and one difficulties within and without that
+have beset me, I am able to appear before you again and tell you of
+advance.
+
+[Illustration: FIG. 1]
+
+Practical men know well that there is a wide difference between a model and
+a full sized machine; and when I decided to construct a full sized tramcar
+and lay out a full sized track, I found it necessary to make many
+alterations of detail, my chief difficulty being so to design my work as to
+facilitate construction and allow of compensation for that inaccuracy of
+workmanship which I have come to regard as inevitable.
+
+In order to satisfy the directors of a tramway company of the practical
+nature of my system before disturbing their lines, I have laid, in a field
+near the works of Messrs. Smith, Baker & Co., Manchester, a track 110 yards
+long, 4 ft. 81/2 in. gauge, and I have constructed a full sized street
+tramcar to run thereon. My negotiations being with a company in a town
+where there are no steep gradients, and where the coefficient of friction
+of ordinary wheels would be sufficient for all tractive purposes, I thought
+it better to avoid the complication involved in employing a large central
+wheel with a broad surface specially designed for hilly districts, and with
+which I had mounted a gradient of one in sixteen.
+
+[Illustration: FIG. 2]
+
+But as the line in question was laid with all the curves unnecessarily
+quick, even those in the "pass-bies," I thought it expedient to employ
+differential gear, as illustrated at D, Fig. 1, which is a sketch plan
+showing the mechanism employed. M is a Siemens electric motor running at
+650 revolutions per minute; E is a combination of box gearing, frictional
+clutch, and chain pinion, and from this pinion a steel chain passes around
+the chain-wheel, H, which is free to revolve upon the axle, and carries
+within it the differential pinion, gearing with the bevel-wheel, B squared, keyed
+upon the sleeve of the loose tram-wheel, T squared, and with the bevel-wheel, B,
+keyed upon the axle, to which the other tram-wheel, T, is attached. To the
+other tram-wheels no gear is connected; one of them is fast to the axle,
+and the other runs loose, but to them the brake is applied in the usual
+manner.
+
+The electric current from the collector passes, by means of a copper wire,
+and a switch upon the dashboard of the car, and resistance coils placed
+under the seats, to the motor, and from the motor by means of an adjustable
+clip (illustrated in diagram, Fig. 2) to the axles, and by them through the
+four wheels to the rails, which form the return circuit.
+
+[Illustration: FIG. 3]
+
+I have designed many modifications of the track, but it is, perhaps, best
+at present to describe only that which I have in actual use, and it is
+illustrated in diagram, Fig. 3, which is a sectional and perspective view
+of the central channel. L is the surface of the road, and SS are the
+sleepers, CC are the chairs which hold the angle iron, AA forming the
+longitudinally slotted center rail and the electric lead, which consists of
+two half-tubes of copper insulated from the chairs by the blocks, I, I. A
+special brass clamp, free to slide upon the tube, is employed for this
+purpose, and the same form of clamp serves to join the two ends of the
+copper tubes together and to make electric contact. Two half-tubes instead
+of one slotted tube have been employed, in order to leave a free passage
+for dirt or wet to fall through the slot in the center rail to the drain
+space, G. Between chair and chair hewn granite or artificial stone is
+employed, formed, as shown in the drawing, to complete the surface of the
+road and to form a continuous channel or drain. In order that this drain
+may not become choked, at suitable intervals, in the length of the track,
+sump holes are formed as illustrated in diagram, Fig. 4 These sump holes
+have a well for the accumulation of mud, and are also connected with the
+main street drain, so that water can freely pass away. The hand holes
+afford facility for easily removing the dirt.
+
+In a complete track these hand holes would occasionally be wider than shown
+here, for the purpose of removing or fixing the collector, Fig. 5, which
+consists of two sets of spirally fluted rollers free to revolve upon
+spindles, which are held by knuckle-joints drawn together by spiral
+springs; by this means the pressure of the rollers against the inside of
+the tube is constantly maintained, and should any obstruction occur in the
+tube the spiral flute causes it to revolve, thus automatically cleansing
+the tubes.
+
+[Illustration: FIG. 4]
+
+The collector is provided with two steel plates, which pass through the
+slit in the center rail; the lower ends of these plates are clamped by the
+upper frame of the collector, insulating material being interposed, and the
+upper ends are held in two iron cheeks. Between these steel plates
+insulated copper strips are held, electrically connected with the collector
+and with the adjustable clip mounted upon the iron cheeks; this clip holds
+the terminal on the end of the wire (leading to the motor) firmly enough
+for use, the cheeks being also provided with studs for the attachment of
+leather straps hooked on to the framework of the car, one for the forward
+and one for backward movement of the collector. These straps are strong
+enough for the ordinary haulage of the collector, and for the removal of
+pebbles and dirt that may get into the slit; but should any absolute block
+occur then they break and the terminal is withdrawn from the clip; the
+electric contact being thereby broken the car stops, the obstruction can
+then be removed and the collector reconnected without damage and with
+little delay.
+
+[Illustration: FIG. 5]
+
+In order to secure continuity of the center rail throughout the length of
+the track, and still provide for the removal of the collector at frequent
+intervals, the framework of the collector is so made that, by slackening
+the side-bolts, the steel plates can be drawn upward and the collector
+itself withdrawn sideways through the hand holes, one of the half-tubes
+being removed for the purpose.
+
+Fig. 6 illustrates another arrangement that I have constructed, both of
+collector and method of collecting.
+
+[Illustration: FIG. 6]
+
+As before mentioned, the arrangement now described has been carried out in
+a field near the works of Messrs. Smith, Baker & Co., Cornbrook Telegraph
+Works, Manchester, and its working efficiency has been most satisfactory.
+After a week of rain and during drenching showers the car ran with the same
+speed and under the same control as when the ground was dry.
+
+This I account for by the theory that when the rails are wet and the tubes
+moist the better contact made compensates for the slight leakage that may
+occur.
+
+At the commencement of my paper I promised to confine myself to work done;
+I therefore abstain from describing various modifications of detail for the
+same purpose. But one method of supporting and insulating the conductor in
+the channel may be suggested by an illustration of the plan I adopted for a
+little pleasure line in the Winter Gardens, Blackpool.
+
+[Illustration: FIG. 7.]
+
+Fig. 7. There the track being exclusively for the electric railway, it was
+not necessary to provide a center channel; the conductor has therefore been
+placed in the center of the track, and consists of bar iron 11/4 in. by 1/2
+in., and is held vertically by means of studs riveted into the side; these
+studs pass through porcelain insulators, and by means of wooden clamps and
+wedges are held in the iron chairs which rest upon the sleepers. The iron
+conductors were placed vertically to facilitate bending round the sharp
+curves which were unavoidable on this line.
+
+The collector consists of two metal slippers held together by springs,
+attached to the car by straps and electrically connected to the motor by
+clips in the same manner as the one employed in Manchester.
+
+I am glad to say that, notwithstanding the curves with a radius of 55 feet
+and gradients of 1 in 57, this line is also a practical success.
+
+       *       *       *       *       *
+
+
+
+
+FIRES IN LONDON AND NEW YORK.
+
+
+When the chief of the London Fire Brigade visited the United States in
+1882, he was, as is the general rule on the other side of the Atlantic,
+"interviewed"--a custom, it may be remarked, which appears to be gaining
+ground also in this country. The inferences drawn from these interviews
+seem to be that the absence of large fires in London was chiefly due to the
+superiority of our fire brigade, and that the greater frequency of
+conflagrations in American cities, and particularly in New York, was due to
+the inferiority of their fire departments. How unjust such a comparison
+would be is shown in a paper presented by Mr. Edward B. Dorsey, a member
+of the American Society of Civil Engineers, to that association, in which
+the author discusses the comparative liability to and danger from
+conflagrations in London and in American cities. He found from an
+investigation which he conducted with much care during a visit to London
+that it is undoubtedly true that large fires are much less frequent in the
+metropolis than in American cities; but it is equally true that the
+circumstances existing in London and New York are quite different. As it is
+a well-known fact that the promptness, efficiency, and bravery of American
+firemen cannot be surpassed, we gladly give prominence to the result of the
+author's investigations into the true causes of the great liability of
+American cities to large fires. In a highly interesting comparison the
+writer has selected New York and London as typical cities, although his
+observations will apply to most American and English towns, if, perhaps,
+with not quite the same force. In the first place, the efforts of the
+London Fire Brigade receive much aid from our peculiarly damp climate. From
+the average of eleven years (1871-1881) of the meteorological observations
+made at the Greenwich Observatory, it appears that in London it rains, on
+the average, more than three days in the week, that the sun shines only
+one-fourth of the time he is above the horizon, and that the atmosphere
+only lacks 18 per cent. of complete saturation, and is cloudy seven-tenths
+of the time. Moreover, the humidity of the atmosphere in London is very
+uniform, varying but little in the different months. Under these
+circumstances, wood will not be ignited very easily by sparks or by contact
+with a weak flame. This is very different from the condition of wood in the
+long, hot, dry seasons of the American continent. The average temperature
+for the three winter months in London is 38.24 degrees Fahr.; in New York
+it is 31.56 degrees, or 6.68 degrees lower. This lower range of temperature
+must be the cause of many conflagrations, for, to make up for the
+deficiency in the natural temperature, there must be in New York many more
+and larger domestic fires. The following statistics, taken from the records
+of the New York Fire Department, show this. In the three winter months of
+1881, January, February, and December, there were 522 fire alarms in New
+York, or an average per month of 174; in the remaining nine months 1,263,
+or an average per month of 140. In the corresponding three winter months of
+1882 there were 602 fire alarms, or an average per month of 201; in the
+remaining nine months 1,401, or an average per month of 155. In round
+numbers there were in 1881 one-fourth, and in 1882 one-third more fire
+alarms in the three winter months than in the nine warmer months. We are
+not aware that similar statistics have ever been compiled for London, and
+are consequently unable to draw comparison; but, speaking from
+recollection, fires appear to be more frequent also in London during the
+winter months.
+
+Another cause of the greater frequency of fires in New York and their more
+destructive nature is the greater density of population in that city. The
+London Metropolitan Police District covers 690 square miles, extending 12
+to 15 miles in every direction from Charing Cross, and contained in 1881 a
+population of 4,764,312; but what is generally known as London covers 122
+square miles, containing, in 1881, 528,794 houses, and a population of
+3,814,574, averaging 7.21 persons per house, 49 per acre, and 31,267 per
+square mile. Now let us look at New York. South of Fortieth Street between
+the Hudson and East Rivers, New York has an area of 3,905 acres, a fraction
+over six square miles, exclusive of piers, and contained, according to the
+census of 1880, a population of 813,076. This gives 208 persons per acre.
+The census of 1880 reports the total number of dwellings in New York at
+73,684; total population, 1,206,299; average per dwelling, 16.37. Selecting
+for comparison an area about equal from the fifteen most densely populated
+districts or parishes of London, of an aggregate area of 3,896 acres, and
+with a total population of 746,305, we obtain 191.5 persons per acre. Thus
+briefly New York averaged 208 persons per acre, and 16.37 per dwelling;
+London, for the same area, 191.5 persons per acre, and 7.21 per house. But
+this comparison is scarcely fair, as in London only the most populous and
+poorest districts are included, corresponding to the entirely tenement
+districts of New York, while in the latter city it includes the richest and
+most fashionable sections, as well as the poorest. If tenement districts
+were taken alone, the population would be found much more dense, and New
+York proportionately much more densely populated. Taking four of the most
+thickly populated of the London districts (East London, Strand, Old Street,
+St. Luke's, St. Giles-in-the-Fields, and St. George, Bloomsbury), we find
+on a total area of 792 acres a population of 197,285, or an average of 249
+persons per acre. In four of the most densely populated wards of New York
+(10th, 11th, 13th, and 17th), we have on an area of 735 acres a population
+of 258,966, or 352 persons per acre. This is 40 per cent. higher than in
+London, the districts being about the same size, each containing about
+1-1/5 square miles. Apart from the greater crowding which takes place in
+New York, and the different style of buildings, another very fertile cause
+of the spreading of fires is the freer use of wood in their construction.
+It is asserted that in New York there is more than double the quantity of
+wood used in buildings per acre than in London. From a house census
+undertaken in 1882 by the New York Fire Department, moreover, it appears
+that there were 106,885 buildings including sheds, of which 28,798 houses
+were built of wood or other inflammable materials, besides 3,803 wooden
+sheds, giving a total of 32,601 wooden buildings.
+
+We are not aware that there are any wooden houses left in London. There are
+other minor causes which act as checks upon the spreading of fires in
+London. London houses are mostly small in size, and fires are thus confined
+to a limited space between brick walls. Their walls are generally low and
+well braced, which enable the firemen to approach them without danger.
+About 60 per cent. of London houses are less than 22 feet high from the
+pavement to the eaves; more than half of the remainder are less than 40
+feet high, very few being over 50 feet high. This, of course, excludes the
+newer buildings in the City. St. James's Palace does not exceed 40 feet,
+the Bank of England not over 30 feet in height; but these are exceptional
+structures. Fireproof roofings and projecting party walls also retard the
+spreading of conflagrations. The houses being comparatively low and small,
+the firemen are enabled to throw water easily over them, and to reach their
+roofs with short ladders. There is in London an almost universal absence of
+wooden additions and outbuildings, and the New York ash barrel or box kept
+in the house is also unknown. The local authorities in London keep a strict
+watch over the manufacture or storage of combustible materials in populous
+parts of the city. Although overhead telegraph wires are multiplying to an
+alarming extent in London, their number is nothing to be compared to their
+bewildering multitude in New York, where their presence is not only a
+hinderance to the operations of the firemen, but a positive danger to their
+lives. Finally--and this has already been partly dealt with in speaking of
+the comparative density of population of the two cities--a look at the map
+of London will show us how the River Thames and the numerous parks,
+squares, private grounds, wide streets, as well as the railways running
+into London, all act as effectual barriers to the extension of fires.
+
+The recent great conflagrations in the city vividly illustrate to Londoners
+what fire could do if their metropolis were built on the New York plan. The
+City, however, as we have remarked, is an exceptional part of London, and,
+taking the British metropolis as it is, with its hundreds of square miles
+of suburbs, and contrasting its condition with that of New York, we are led
+to adopt the opinion that London, with its excellent fire brigade, is safe
+from a destructive conflagration. It was stated above, and it is repeated
+here, that the fire brigade of New York is unsurpassed for promptness,
+skill, and heroic intrepidity, but their task, by contrast, is a heavy one
+in a city like New York, with its numerous wooden buildings, wooden or
+asphalt roofs, buildings from four to ten stories high, with long unbraced
+walls, weakened by many large windows, containing more than ten times the
+timber an average London house does, and that very inflammable, owing to
+the dry and hot American climate. But this is not all. In New York we find
+the five and six story tenement houses with two or three families on each
+floor, each with their private ash barrel or box kept handy in their rooms,
+all striving to keep warm during the severe winters of North America. We
+also find narrow streets and high buildings, with nothing to arrest the
+extension of a fire except a few small parks, not even projecting or
+effectual fire-walls between the several buildings. And to all this must be
+added the perfect freedom with which the city authorities of New York allow
+in its most populous portions large stables, timber yards, carpenters'
+shops, and the manufacture and storage of inflammable materials. Personal
+liberty could not be carried to a more dangerous extent. We ought to be
+thankful that in such matters individual freedom is somewhat hampered in
+our old-fashioned and quieter-going country.--_London Morning Post_.
+
+       *       *       *       *       *
+
+
+
+
+THE LATEST KNOWLEDGE ABOUT GAPES.
+
+
+The gape worm may be termed the _bete noir_ of the poultry-keeper--his
+greatest enemy--whether he be farmer or fancier. It is true there are some
+who declare that it is unknown in their poultry-yards--that they have never
+been troubled with it at all. These are apt to lay it down, as I saw a
+correspondent did in a recent number of the _Country Gentleman_, that the
+cause is want of cleanliness or neglect in some way. But I can vouch that
+that is not so. I have been in yards where everything was first-rate, where
+the cleanliness was almost painfully complete, where no fault in the way of
+neglect could be found, and yet the gapes were there; and on the other
+hand, I have known places where every condition seemed favorable to the
+development of such a disease, and there it was absent--this not in
+isolated cases, but in many. No, we must look elsewhere for the cause.
+
+Observations lead me to the belief that gapes are more than usually
+troublesome during a wet spring or summer following a mild winter. This
+would tend to show that the egg from which the worm (that is in itself the
+disease) emerges is communicated from the ground, from the food eaten, or
+the water drunk, in the first instance, but it is more than possible that
+the insects themselves may pass from one fowl to another. All this we can
+accept as a settled fact, and also any description of the way in which the
+parasitic worms attach themselves to the throats of the birds, and cause
+the peculiar gaping of the mouth which gives the name to the disease.
+
+Many remedies have been suggested, and my object now is to communicate some
+of the later ones--thus to give a variety of methods, so that in case of
+the failure of one, another will be at hand ready to be tried. It is a
+mistake always to pin the faith to one remedy, for the varying conditions
+found in fowls compel a different treatment. The old plan of dislodging the
+worms with a feather is well known, and need not be described again. But I
+may mention that in this country some have found the use of an ointment,
+first suggested by Mr. Lewis Wright, I believe, most valuable. This is made
+of mercurial ointment, two parts; pure lard, two parts; flour of sulphur,
+one part; crude petroleum, one part--and when mixed together is applied to
+the heads of the chicks as soon as they are dry after hatching. Many have
+testified that they have never found this to fail as a preventive, and if
+the success is to be attributed to the ointment, it would seem as if the
+insects are driven off by its presence, for the application to the heads
+merely would not kill the eggs.
+
+Some time ago Lord Walsingham offered, through the Entomological Society of
+London, a prize for the best life history of the gapes disease, and this
+has been won by the eminent French scientist M. Pierre Megnin, whose essay
+has been published by the noble donor. His offer was in the interest of
+pheasant breeders, but the benefit is not confined to that variety of game
+alone, for it is equally applicable to all gallinaceous birds troubled with
+this disease. The pamphlet in question is a very valuable work, and gives
+very clearly the methods by which the parasite develops. But for our
+purpose it will be sufficient to narrate what M. Megnin recommends for the
+cure of it. These are various, as will be seen, and comprise the experience
+of other inquirers as well as himself.
+
+He states that Montague obtained great success by a combination of the
+following methods: Removal from infested runs; a thorough change of food,
+hemp seed and green vegetables figuring largely in the diet; and for
+drinking, instead of plain water, an infusion of rue and garlic. And Megnin
+himself mentions an instance of the value of garlic. In the years 1877 and
+1878, the pheasant preserves of Fontainebleau were ravaged by gapes. The
+disease was there arrested and totally cured, when a mixture, consisting of
+yolks of eggs, boiled bullock's heart, stale bread crumbs, and leaves of
+nettle, well mixed and pounded together with garlic, was given, in the
+proportion of one clove to ten young pheasants. The birds were found to be
+very fond of this mixture, but great care was taken to see that the
+drinking vessels were properly cleaned out and refilled with clean, pure
+water twice a day. This treatment has met with the same success in other
+places, and if any of your readers are troubled with gapes and will try it,
+I shall be pleased to see the results narrated in the columns of the
+_Country Gentleman_. Garlic in this case is undoubtedly the active
+ingredient, and as it is volatile, when taken into the stomach the breath
+is charged with it, and in this way (for garlic is a powerful vermifuge)
+the worms are destroyed.
+
+Another remedy recommended by M. Megnin was the strong smelling vermifuge
+assafoetida, known sometimes by the suggestive name of "devil's dung." It
+has one of the most disgusting oders possible, and is not very pleasant to
+be near. The assafoetida was mixed with an equal part of powdered yellow
+gentian, and this was given to the extent of about 8 grains a day in the
+food. As an assistance to the treatment, with the object of killing any
+embryos in the drinking water, fifteen grains of salicylate of soda was
+mixed with a pint and three-quarters of water. So successful was this, that
+on M. De Rothschild's preserves at Rambouillet, where a few days before
+gapes were so virulent that 1,200 pheasants were found dead every morning,
+it succeeded in stopping the epidemic in a few days. But to complete the
+matter, M. Megnin adds that it is always advisable to disinfect the soil of
+preserves. For this purpose, the best means of destroying any eggs or
+embryos it may contain is to water the ground with a solution of sulphuric
+acid, in the proportion of a pennyweight to three pints of water, and also
+birds that die of the disease should be deeply buried in lime.
+
+Fumigation with carbolic acid is an undoubted cure, but then it is a
+dangerous one, and unless very great care is taken in killing the worms,
+the bird is killed also. Thus many find this a risky method, and prefer
+some other. Lime is found to be a valuable remedy. In some districts of
+England, where lime-kilns abound, it is a common thing to take children
+troubled with whooping-cough there. Standing in the smoke arising from the
+kilns, they are compelled to breathe it. This dislodges the phlegm in the
+throat, and they are enabled to get rid of it. Except near lime-kilns, this
+cannot be done to chickens, but fine slaked lime can be used, either alone
+or mixed with powdered sulphur, two parts of the former to one of the
+latter. The air is charged with this fine powder, and the birds, breathing
+it, cough, and thus get rid of the worms, which are stupefied by the lime,
+and do not retain so firm a hold on the throat. An apparatus has recently
+been introduced to spread this lime powder. It is in the form of an
+air-fan, with a pointed nozzle, which is put just within the coop at night,
+when the birds are all within. The powder is already in a compartment made
+for it, and by the turning of a handle, it is driven through the nozzle,
+and the air within the coop charged with it. There is no waste of powder,
+nor any fear that it will not be properly distributed. Experienced pheasant
+and poultry breeders state that by the use of this once a week, gapes are
+effectually prevented. In this case, also, I shall be glad to learn the
+result if tried.
+
+STEPHEN BEALE.
+
+H----, Eng., Aug. 1.
+
+--_Country Gentleman_.
+
+       *       *       *       *       *
+
+
+
+
+WOLPERT'S METHOD OF ESTIMATING THE AMOUNT OF CARBONIC ACID IN THE AIR.
+
+
+There is a large number of processes and apparatus for estimating the
+amount of carbonic acid in the air. Some of them, such as those of
+Regnault, Reiset, the Montsouris observers (Fig. 1), and Brand, are
+accurate analytical instruments, and consequently quite delicate, and not
+easily manipulated by hygienists of middling experience. Others are less
+complicated, and also less exact, but still require quite a troublesome
+manipulation--such, for example, as the process of Pettenkofer, as modified
+by Fodor, that of Hesse, etc.
+
+[Illustration: APPARATUS FOR ESTIMATING THE CARBONIC ACID OF THE AIR.
+FIG. 1.--Montsouris Apparatus. FIG. 2.--Smith's Minimetric Apparatus. FIG.
+3.--Bertin-Sans Apparatus. FIG. 4.--Bubbling Glass. FIG. 5.--Pipette. FIG.
+6.--Arrangement of the U-shaped Tube. FIG. 7.--Wolpert's Apparatus.]
+
+Hygienists have for some years striven to obtain some very simple apparatus
+(rather as an indicator than an analytical instrument) that should permit
+it to be quickly ascertained whether the degree of impurity of a place was
+incompatible with health, and in what proportion it was so. It is from such
+efforts that have resulted the processes of Messrs. Smith. Lunge,
+Bertin-Sans, and the apparatus of Prof. Wolpert (Fig. 7).
+
+It is of the highest interest to ascertain the proportion of carbonic acid
+in the air, and especially in that of inhabited places, since up to the
+present this is the best means of finding out how much the air that we are
+breathing is polluted, and whether there is sufficient ventilation or not.
+Experiment has, in fact, demonstrated that carbonic acid increases in the
+air of inhabited rooms in the same way as do those organic matters which
+are difficult of direct estimation. Although a few ten-thousandths more of
+carbonic acid in our air cannot of themselves endanger us, yet they have on
+another hand a baneful significance, and, indeed, the majority of
+hygienists will not tolerate more than six ten-millionths of this element
+in the air of dwellings, and some of them not more than five
+ten-millionths.
+
+Carbonic acid readily betrays its presence through solutions of the
+alkaline earths such as baryta and chalk, in which its passage produces an
+insoluble carbonate, and consequently makes the liquid turbid. If, then,
+one has prepared a solution of baryta or lime, of which a certain volume is
+made turbid by the passage of a likewise known volume of CO_{2}, it will be
+easy to ascertain how much CO_{2} a certain air contains, from the volume
+of the latter that it will be necessary to pass through the basic solution
+in order to obtain the amount of turbidity that has been taken as a
+standard. The problem consists in determining the minimum of air required
+to make the known solution turbid. Hence the name "minimetric estimation,"
+that has been given to this process. Prof. Lescoeur has had the goodness to
+construct for me a Smith's minimetric apparatus (Fig. 2) with the ingenious
+improvements that have been made in it by Mr. Fischli, assistant to Prof.
+Weil, of Zurich. I have employed it frequently, and I use it every year in
+my lectures. I find it very practical, provided one has got accustomed to
+using it. It is, at all events, of much simpler manipulation than that of
+Bertin-Sans, although the accuracy of the latter may be greater (Figs. 3,
+4, 5, and 6). But it certainly has more than one defect, and some of the
+faults that have been found with it are quite serious. The worst of these
+consists in the difficulty of catching the exact moment at which the
+turbidity of the basic liquid is at the proper point for arresting the
+operation. In addition to this capital defect, it is regrettable that it is
+necessary to shake the flask that contains the solution after every
+insufflation of air, and also that the play of the valves soon becomes
+imperfect. Finally, Mr. Wolpert rightly sees one serious drawback to the
+use of baryta in an apparatus that has to be employed in schools, among
+children, and that is that this substance is poisonous. This gentleman
+therefore replaces the solution of baryta by water saturated with lime,
+which costs almost nothing, and the preparation of which is exceedingly
+simple. Moreover, it is a harmless agent.
+
+The apparatus consists of two parts. The first of these is a glass tube
+closed at one end, and 12 cm. in length by 12 mm. in diameter. Its bottom
+is of porcelain, and bears on its inner surface the date 1882 in black
+characters. Above, and at the level that corresponds to a volume of three
+cubic centimeters, there is a black line which serves as an invariable
+datum point. A rubber bulb of twenty-eight cubic centimeters capacity is
+fixed to a tube which reaches its bottom, and is flanged at the other
+extremity (Fig. 7).
+
+The operation is as follows:
+
+The saturated, but limpid, solution of lime is poured into the first tube
+up to the black mark, the tube of the air bulb is introduced into the lime
+water in such a way that its orifice shall be in perfect contact with the
+bottom of the other tube, and then, while the bulb is held between the fore
+and middle fingers of the upturned hand, one presses slowly with the thumb
+upon its bottom so as to expel all the air that it contains. This air
+enters the lime-water bubble by bubble. After this the tube is removed from
+the water, and the bulb is allowed to fill with air, and the same maneuver
+is again gone through with. This is repeated until the figures 1882, looked
+at from above, cease to be clearly visible, and disappear entirely after
+the contents of the tube have been vigorously shaken.
+
+The measures are such that the turbidity supervenes at once if the air in
+the bulb contains twenty thousandths of CO_{2}. If it becomes necessary to
+inject the contents of the bulb into the water twice, it is clear that the
+proportion is only ten thousandths; and if it requires ten injections the
+air contains ten times less CO_{2} than that having twenty thousandths, or
+only two per cent. A table that accompanies the apparatus has been
+constructed upon this basis, and does away with the necessity of making
+calculations.
+
+An air that contained ten thousandths of CO_{2}, or even five, would be
+almost as deleterious, in my opinion, as one of two per cent. It is of no
+account, then, to know the proportions intermediate to these round numbers.
+Yet it is possible, if the case requires it, to obtain an indication
+between two consecutive figures of the scale by means of another bulb whose
+capacity is only half that of the preceding. Thus, two injections of the
+large bulb, followed by one of the small, or two and a half injections,
+correspond to a richness of 8 thousandths of CO_{2}; and 51/2 to 3.6
+thousandths. This half-bulb serves likewise for another purpose. From the
+moment that the large bulb makes the lime-water turbid with an air
+containing two per cent. of CO_{2}, it is clear that the small one can
+cause the same turbidity only with air twice richer in CO_{2}, _i.e._, of
+four per cent.
+
+This apparatus, although it makes no pretensions to extreme accuracy, is
+capable of giving valuable information. The table that accompanies it is
+arranged for a temperature of 17 deg. and a pressure of 740 mm. But different
+meteorological conditions do not materially alter the results. Thus, with
+10 deg. less it would require thirty-one injections instead of thirty, and
+CO_{2} would be 0.64 per 1,000 instead of 0.66; and with 10 deg. more, thirty
+injections instead of thirty one.
+
+The apparatus is contained in a box that likewise holds a bottle of
+lime-water sufficient for a dozen analyses, the table of proportions of
+CO_{2}, and the apparatus for cleaning the tubes. The entire affair is
+small enough to be carried in the pocket.--_J. Arnould, in Science et
+Nature_.
+
+       *       *       *       *       *
+
+[NATURE.]
+
+
+
+
+THE VOYAGE OF THE VETTOR PISANI.
+
+
+Knowing how much _Nature_ is read by all the naturalists of the world, I
+send these few lines, which I hope will be of some interest.
+
+The Italian R.N. corvette Vettor Pisani left Italy in April, 1882, for a
+voyage round the world with the ordinary commission of a man-of-war. The
+Minister of Marine, wishing to obtain scientific results, gave orders to
+form, when possible, a marine zoological collection, and to carry on
+surveying, deep-sea soundings, and abyssal thermometrical measurements. The
+officers of the ship received their different scientific charges, and Prof.
+Dohrn, director of the Zoological Station at Naples, gave to the writer
+necessary instructions for collecting and preserving sea animals.
+
+At the end of 1882 the Vettor Pisani visited the Straits of Magellan, the
+Patagonian Channels, and Chonos and Chiloe islands; we surveyed the Darwin
+Channel, and following Dr. Cuningham's work (who visited these places on
+board H.M.S. Nassau), we made a numerous collection of sea animals by
+dredging and fishing along the coasts.
+
+While fishing for a big shark in the Gulf of Panama during the stay of our
+ship in Taboga Island, one day in February, with a dead clam, we saw
+several great sharks some miles from our anchorage. In a short time several
+boats with natives went to sea, accompanied by two of the Vettor Pisani's
+boats.
+
+Having wounded one of these animals in the lateral part of the belly, we
+held him with lines fixed to the spears; he then began to describe a very
+narrow curve, and irritated by the cries of the people that were in the
+boats, ran off with a moderate velocity. To the first boat, which held the
+lines just mentioned, the other boats were fastened, and it was a rather
+strange emotion to feel ourselves towed by the monster for more than three
+hours with a velocity that proved to be two miles per hour. One of the
+boats was filled with water. At last the animal was tired by the great loss
+of blood, and the boats assembled to haul in the lines and tow the shark on
+shore.
+
+With much difficulty the nine boats towed the animal alongside the Vettor
+Pisani to have him hoisted on board, but it was impossible on account of
+his colossal dimensions. But as it was high water we went toward a sand
+beach with the animal, and we had him safely stranded at night.
+
+With much care were inspected the mouth, the nostrils, the ears, and all
+the body, but no parasite was found. The eyes were taken out and prepared
+for histological study. The set of teeth was all covered by a membrane that
+surrounded internally the lips; the teeth are very little, and almost in a
+rudimental state. The mouth, instead of opening in the inferior part of the
+head, as in common sharks, was at the extremity of the head; the jaws
+having the same bend.
+
+Cutting the animal on one side of the backbone we met (1) a compact layer
+of white fat 20 centimeters deep; (2) the cartilaginous ribs covered with
+blood vessels; (3) a stratum of flabby, stringy, white muscle, 60
+centimeters high, apparently in adipose degeneracy; (4) the stomach.
+
+By each side of the backbone he had three chamferings, or flutings, that
+were distinguished by inflected interstices. The color of the back was
+brown with yellow spots that became close and small toward the head, so as
+to be like marble spots. The length of the shark was 8.90 m. from the mouth
+to the _pinna caudalis_ extremity, the greatest circumference 6.50 m., and
+2.50 m. the main diameter (the outline of the two projections is made for
+giving other dimensions).
+
+The natives call the species _Tintoreva_, and the most aged of the village
+had only once before fished such an animal, but smaller. While the animal
+was on board we saw several _Remora_ about a foot long drop from his mouth;
+it was proved that these fish lived fixed to the palate, and one of them
+was pulled off and kept in the zoological collection of the ship.
+
+The Vettor Pisani has up the present visited Gibraltar, Cape Verde Islands,
+Pernambuco, Rio Janeiro, Monte Video, Valparaiso, many ports of Peru,
+Guayaquil, Panama, Galapagos Islands, and all the collections were up to
+this sent to the Zoological Station at Naples to be studied by the
+naturalists. By this time the ship left Callao for Honolulu, Manila, Hong
+Kong, and, as the Challenger had not crossed the Pacific Ocean in these
+directions, we made several soundings and deep-sea thermometrical
+measurements from Callao to Honolulu. Soundings are made with a steel wire
+(Thompson system) and a sounding-rod invented by J. Palumbo, captain of the
+ship. The thermometer employed is a Negretti and Zambra deep-sea
+thermometer, improved by Captain Maguaghi (director of the Italian R.N.
+Hydrographic Office).
+
+With the thermometer wire has always been sent down a tow-net which opens
+and closes automatically, also invented by Captain Palumbo. This tow-net
+has brought up some little animals that I think are unknown.
+
+G. CHIERCHIA.
+
+
+Honolulu July 1.
+
+The shark captured by the Vettor Pisani in the Gulf of Panama is _Rhinodon
+typicus_, probably the most gigantic fish in existence. Mr. Swinburne Ward,
+formerly commissioner of the Seychelles, has informed me that it attains to
+a length of 50 feet or more, which statement was afterward confirmed by
+Prof. E.P. Wright. Originally described by Sir A. Smith from a single
+specimen which was killed in the neighborhood of Cape Town, this species
+proved to be of not uncommon occurrence in the Seychelles Archipelago,
+where it is known by the name of "Chagrin." Quite recently Mr. Haly
+reported the capture of a specimen on the coast of Ceylon. Like other large
+sharks (_Carcharodon rondeletii, Selache maxima_, etc.), Rhinodon has a
+wide geographical range, and the fact of its occurrence on the Pacific
+coast of America, previously indicated by two sources, appears now to be
+fully established. T. Gill in 1865 described a large shark known in the
+Gulf of California by the name of "Tiburon ballenas" or whale-shark, as a
+distinct genus--_Micristodus punctatus_--which, in my opinion, is the same
+fish. And finally, Prof. W. Nation examined in 1878 a specimen captured at
+Callao. Of this specimen we possess in the British Museum a portion of the
+dental plate. The teeth differ in no respect from those of a Seychelles
+Chagrin; they are conical, sharply pointed, recurved, with the base of
+attachment swollen. Making no more than due allowance for such variations
+in the descriptions by different observers as are unavoidable in accounts
+of huge creatures examined by some in a fresh, by others in a preserved,
+state, we find the principal characteristics identical in all these
+accounts, viz.: the form of the body, head, and snout, relative
+measurements, position of mouth, nostrils, and eyes, dentition, peculiar
+ridges on the side of the trunk and tail, coloration, etc. I have only to
+add that this shark is stated to be of mild disposition and quite harmless.
+Indeed, the minute size of its teeth has led to the belief in the
+Seychelles that it is a herbivorous fish, which, however, is not probable.
+
+ALBERT GUNTHER.
+
+Natural History Museum, _July 30_.
+
+       *       *       *       *       *
+
+
+
+
+THE GREELY ARCTIC EXPEDITION.
+
+
+[Illustration: THE GREELY ARCTIC EXPEDITION.--THE FARTHEST POINT NORTH.]
+
+Some account has been given of the American Meteorological Expedition,
+commanded by Lieutenant, now Major, Greely, of the United States Army, in
+the farthest north channels, beyond Smith Sound, that part of the Arctic
+regions where the British Polar expedition, in May, 1876, penetrated to
+within four hundred geographical miles of the North Pole. The American
+expedition, in 1883, succeeded in getting four miles beyond, this being
+effected by a sledge party traveling over the snow from Fort Conger, the
+name they had given to their huts erected on the western shore near
+Discovery Cove, in Lady Franklin Sound. The farthest point reached, on May
+18, was in latitude 83 deg. 24 min. N.; longitude 40 deg. 46 min. W., on
+the Greenland coast. The sledge party was commanded by Lieutenant Lockwood,
+and the following particulars are supplied by Sergeant Brainerd, who
+accompanied Lieutenant Lockwood on the expedition. During their sojourn in
+the Arctic regions the men were allowed to grow the full beard, except
+under the mouth, where it was clipped short. They wore knitted mittens, and
+over these heavy seal-skin mittens were drawn, connected by a tanned
+seal-skin string that passed over the neck, to hold them when the hands
+were slipped out. Large tanned leather pockets were fastened outside the
+jackets, and in very severe weather jerseys were sometimes worn over the
+jackets for greater protection against the intense cold. On the sledge
+journeys the dogs were harnessed in a fan-shaped group to the traces, and
+were never run tandem. In traveling, the men were accustomed to hold on to
+the back of the sledge, never going in front of the team, and often took
+off their heavy overcoats and threw them on the load. When taking
+observations with the sextant, Lieutenant Lockwood generally reclined on
+the snow, while Sergeant Brainerd called time and made notes, as shown in
+our illustration. When further progress northward was barred by open water,
+and the party almost miraculously escaped drifting into the Polar sea,
+Lieutenant Lockwood erected, at the highest point of latitude reached by
+civilized man, a pyramidal-shaped cache of stones, six feet square at the
+base, and eight or nine feet high. In a little chamber about a foot square
+half-way to the apex, and extending to the center of the pile, he placed a
+self-recording spirit thermometer, a small tin cylinder containing records
+of the expedition, and then sealed up the aperture with a closely fitting
+stone. The cache was surmounted with a small American flag made by Mrs.
+Greely, but there were only thirteen stars, the number of the old
+revolutionary flag. From the summit of Lockwood Island, the scene presented
+in our illustration, 2,000 feet above the sea, Lieutenant Lockwood was
+unable to make out any land to the north or the northwest. "The awful
+panorama of the Arctic which their elevation spread out before them made a
+profound impression upon the explorers. The exultation which was natural to
+the achievement which they found they had accomplished was tempered by the
+reflections inspired by the sublime desolation of that stern and silent
+coast and the menace of its unbroken solitude. Beyond to the eastward was
+the interminable defiance of the unexplored coast--black, cold, and
+repellent. Below them lay the Arctic Ocean, buried beneath frozen chaos. No
+words can describe the confusion of this sea of ice--the hopeless asperity
+of it, the weariness of its torn and tortured surface. Only at the remote
+horizon did distance and the fallen snow mitigate its roughness and soften
+its outlines; and beyond it, in the yet unattainable recesses of the great
+circle, they looked toward the Pole itself. It was a wonderful sight, never
+to be forgotten, and in some degree a realization of the picture that
+astronomers conjure to themselves when the moon is nearly full, and they
+look down into the great plain which is called the Ocean of Storms, and
+watch the shadows of sterile and airless peaks follow a slow procession
+across its silver surface."--_Illustrated London News_.
+
+       *       *       *       *       *
+
+
+
+
+THE NILE EXPEDITION.
+
+
+[Illustration: WHALER GIG FOR THE NILE.]
+
+As soon as the authorities had finally made up their minds to send a
+flotilla of boats to Cairo for the relief of Khartoum, not a moment was
+lost in issuing orders to the different shipbuilding contractors for the
+completion, with the utmost dispatch, of the 400 "whaler-gigs" for service
+on the Nile. They are light-looking boats, built of white pine, and weigh
+each about 920 lb., that is without the gear, and are supposed to carry
+four tons of provisions, ammunition, and camp appliances, the food being
+sufficient for 100 days. The crew will number twelve men, soldiers and
+sailors, the former rowing, while the latter (two) will attend the helm.
+Each boat will be fitted with two lug sails, which can be worked reefed, so
+as to permit an awning to be fitted underneath for protection to the men
+from the sun. As is well known, the wind blows for two or three months
+alternately up and down the Nile, and the authorities expect the flotilla
+will have the advantage of a fair wind astern for four or five days at the
+least. On approaching the Cataracts, the boats will be transported on
+wooden rollers over the sand to the next level for relaunching.
+
+       *       *       *       *       *
+
+
+
+
+THE PROPER TIME FOR CUTTING TIMBER.
+
+
+_To the Editor of the Oregonian:_
+
+Believing that any ideas relating to this matter will be of some interest
+to your readers in this heavily-timbered region, I therefore propose giving
+you my opinion and conclusions arrived at after having experimented upon
+the cutting and use of timber for various purposes for a number of years
+here upon the Pacific coast.
+
+This, we are all well aware, is a very important question, and one very
+difficult to answer, since it requires observation and experiment through a
+course of many years to arrive at any definite conclusion; and it is a
+question too upon which even at the present day there exists a great
+difference of opinion among men who, being engaged in the lumber business,
+are thereby the better qualified to form an opinion.
+
+Many articles have been published in the various papers of the country upon
+this question for the past thirty years, but in all cases an opinion only
+has been given, which, at the present day, such is the advance and higher
+development of the intellectual faculties of man, that a mere opinion upon
+any question without sufficient and substantial reasons to back it is of
+little value.
+
+My object in writing this is not simply to give an opinion, but how and the
+methods used by which I adopted such conclusions, as well also as the
+reasons why timber is more durable and better when cut at a certain season
+of the year than when cut at any other.
+
+In the course of my investigations of this question for the past thirty
+years, I have asked the opinion of a great many persons who have been
+engaged in the lumber business in various States of the Union, from Maine
+to Wisconsin, and they all agree upon one point, viz., that the winter time
+is the proper time for cutting timber, although none has ever been able to
+give a reason why, only the fact that such was the case, and therefore
+drawing the inference that it was the proper time when timber should be
+cut; and so it is, for one reason only, however, and that is the
+convenience for handling or moving timber upon the snow and ice.
+
+It was while engaged in the business of mining in the mountains of
+California in early days, and having occasion to work often among timber,
+in removing stumps, etc., it was while so engaged that I noticed one
+peculiar fact, which was this--that the stumps of some trees which had been
+cut but two or three years had decayed, while others of the same size and
+variety of pine which had been cut the same year were as sound and firm as
+when first cut. This seemed strange to me, and I found upon inquiry of old
+lumbermen who had worked among timber all their lives, that it was strange
+to them also, and they could offer no explanation; and it was the
+investigation of this singular fact that led me to experiment further upon
+the problem of cutting timber.
+
+It was not, however, until many years after, and when engaged in clearing
+land for farming purposes, that I made the discovery why some stumps should
+decay sooner than others of the same size and variety, even when cut a few
+months afterward.
+
+I had occasion to clear several acres of land which was covered with a very
+dense growth of young pines from two to six inches in diameter (this work
+for certain reasons is usually done in the winter). The young trees, not
+being suitable for fuel, are thrown into piles and burned upon the ground.
+Such land, therefore, on account of the stumps is very difficult to plow,
+as the stumps do not decay for three or four years, while most of the
+larger ones remain sound even longer.
+
+But, for the purpose of experimenting, I cleaned a few acres of ground in
+the spring, cutting them in May and June. I trimmed the poles, leaving them
+upon the ground, and when seasoned hauled them to the house for fuel, and
+found that for cooking or heating purposes they were almost equal to oak;
+and it was my practice for many years afterward to cut these young pines in
+May or June for winter fuel.
+
+I found also that the stumps, instead of remaining sound for any length of
+time, decayed so quickly that they could all be plowed up the following
+spring.
+
+From which facts I draw these conclusions: that if in the cutting of timber
+the main object is to preserve the stumps, cut your trees in the fall or
+winter; but if the value of the timber is any consideration, cut your trees
+in the spring after the sap has ascended the tree, but before any growth
+has taken place or new wood has been formed.
+
+I experimented for many years also in the cutting of timber for fencing,
+fence posts, etc., and with the same results. Those which were cut in the
+spring and set after being seasoned were the most durable, such timber
+being much lighter, tougher, and in all respects better for all variety of
+purposes.
+
+Having given some little idea of the manner in which I experimented, and
+the conclusions arrived at as to the proper time when timber should be cut,
+I now propose to give what are, in my opinion, the reasons why timber cut
+in early summer is much better, being lighter, tougher and more durable
+than if cut at any other time. Therefore, in order to do this it is
+necessary first to explain the nature and value of the sap and the growth
+of a tree.
+
+We find it to be the general opinion at present, as it perhaps has always
+been among lumbermen and those who work among timber, that the sap of a
+tree is an evil which must be avoided if possible, for it is this which
+causes decay and destroys the life and good qualities of all wood when
+allowed to remain in it for an unusual length of time, but that this is a
+mistaken idea I will endeavor to show, not that the decay is due to the
+sap, but to the time when the tree was felled.
+
+We find by experiment in evaporating a quantity of sap of the pine, that it
+is water holding in solution a substance of a gummy nature, being composed
+of albumen and other elementary matters, which is deposited within the
+pores of the wood from the new growth of the tree; that these substances in
+solution, which constitute the sap, and which promote the growth of the
+tree, should have a tendency to cause decay of the wood is an
+impossibility. The injury results from the water only, and the improper
+time of felling the tree.
+
+Of the process in which the sap promotes the growth of the tree, the
+scientist informs us that it is extracted from the soil, and flows up
+through the pores of the wood of the tree, where it is deposited upon the
+fiber, and by a peculiar process of nature the albumen forms new cells,
+which in process of formation crowd and push out from the center, thus
+constituting the growth of the tree in all directions from center to
+circumference. Consequently this new growth of wood, being composed
+principally of albumen, is of a soft, spongy nature, and under the proper
+conditions will decay very rapidly, which can be easily demonstrated by
+experiment.
+
+Hence, we must infer that the proper time for felling the tree is when the
+conditions are such that the rapid decay of a new growth of wood is
+impossible; and this I have found by experiment to be in early summer,
+after the sap has ascended the tree, but before any new growth of wood has
+been formed. The new growth of the previous season is now well matured, has
+become hard and firm, and will not decay. On the contrary, the tree being
+cut when such new growth has not well matured, decay soon takes place, and
+the value of the timber is destroyed. The effect of this cutting and use of
+timber under the wrong conditions can be seen all around us. In the timbers
+of the bridges, in the trestlework and ties of railroads and in the piling
+of the wharves will be found portions showing rapid decay, while other
+portions are yet firm and in sound condition.
+
+Much more might be said in the explanation of this subject, but not wishing
+to extend the subject to an improper length, I will close. I would,
+however, say in conclusion that persons who have the opportunities and the
+inclination can verify the truth of a portion, at least, of what I have
+stated, in a simple manner and in a short time; for instance, by cutting
+two or three young fir or spruce saplings, say about six inches in
+diameter, mark them when cut, and also mark the stumps by driving pegs
+marked to correspond with the trees. Continue this monthly for the space of
+about one year, and note the difference in the wood, which should be left
+out and exposed to the weather until seasoned.
+
+C.W. HASKINS.
+
+       *       *       *       *       *
+
+
+
+
+RAISING FERNS FROM SPORES.
+
+
+[Illustration: 1, PAN; 2, BELL GLASS; 3, SMALL POTS AND LABELS.]
+
+This plan, of which I give a sketch, has been in use by myself for many
+years, and most successfully. I have at various times given it to growers,
+but still I hear of difficulties. Procure a good sized bell-glass and an
+earthenware pan without any holes for drainage. Prepare a number of small
+pots, all filled for sowing, place them inside the pan, and fit the glass
+over them, so that it takes all in easily. Take these filled small pots out
+of the pan, place them on the ground, and well water them with boiling
+water to destroy all animal and vegetable life, and allow them to get
+perfectly cold; use a fine rose. Then taking each small pot separately, sow
+the spores on the surface and label them; do this with the whole number,
+and then place them in the pan under the bell-glass. This had better be
+done in a room, so that nothing foreign can grow inside. Having arranged
+the pots and placed the glass over them, and which should fit down upon the
+pan with ease, take a clean sponge, and tearing it up pack the pieces round
+the outside of the glass, and touching the inner side of the pan all round.
+Water this with cold water, so that the sponge is saturated. Do this
+whenever required, and always use water that has been boiled. At the end of
+six weeks or so the prothallus will perhaps appear, certainly in a week or
+two more; perhaps from unforeseen circumstances not for three months.
+Slowly these will begin to show themselves as young ferns, and most
+interesting it is to watch the results. As the ferns are gradually
+increasing in size pass a small piece of slate under the edge of the
+bell-glass to admit air, and do this by very careful degrees, allowing more
+and more air to reach them. Never water overhead until the seedlings are
+acclimated and have perfect form as ferns, and even then water at the edges
+of the pots. In due time carefully prick out, and the task so interesting
+to watch is performed.--_The Garden_.
+
+       *       *       *       *       *
+
+
+
+
+THE LIFE HISTORY OF VAUCHERIA.
+
+[Footnote: Read before the San Francisco Microscopical Society, August 13,
+and furnished for publication in the _Press_.]
+
+By A.H. BRECKENFELD.
+
+
+Nearly a century ago, Vaucher, the celebrated Genevan botanist, described a
+fresh water filamentous alga which he named _Ectosperma geminata_, with a
+correctness that appears truly remarkable when the imperfect means of
+observation at his command are taken into consideration. His pupil, De
+Candolle, who afterward became so eminent a worker in the same field, when
+preparing his "Flora of France," in 1805, proposed the name of _Vaucheria_
+for the genus, in commemoration of the meritorious work of its first
+investigator. On March 12, 1826, Unger made the first recorded observation
+of the formation and liberation of the terminal or non-sexual spores of
+this plant. Hassall, the able English botanist, made it the subject of
+extended study while preparing his fine work entitled "A History of the
+British Fresh Water Algae," published in 1845. He has given us a very
+graphic description of the phenomenon first observed by Unger. In 1856
+Pringsheim described the true sexual propagation by oospores, with such
+minuteness and accuracy that our knowledge of the plant can scarcely be
+said to have essentially increased since that time.
+
+[Illustration: GROWTH OF THE ALGA, VAUCHERIA, UNDER THE MICROSCOPE.]
+
+_Vaucheria_ has two or three rather doubtful marine species assigned to it
+by Harvey, but the fresh water forms are by far the more numerous, and it
+is to some of these I would call your attention for a few moments this
+evening. The plant grows in densely interwoven tufts, these being of a
+vivid green color, while the plant is in the actively vegetative condition,
+changing to a duller tint as it advances to maturity. Its habitat (with the
+exceptions above noted) is in freshwater--usually in ditches or slowly
+running streams. I have found it at pretty much all seasons of the year, in
+the stretch of boggy ground in the Presidio, bordering the road to Fort
+Point. The filaments attain a length of several inches when fully
+developed, and are of an average diameter of 1/250 (0.004) inch. They
+branch but sparingly, or not at all, and are characterized by consisting of
+a single long tube or cell, not divided by septa, as in the case of the
+great majority of the filamentous algae. These tubular filaments are
+composed of a nearly transparent cellulose wall, including an inner layer
+thickly studded with bright green granules of chlorophyl. This inner layer
+is ordinarily not noticeable, but it retracts from the outer envelope when
+subjected to the action of certain reagents, or when immersed in a fluid
+differing in density from water, and it then becomes distinctly visible, as
+may be seen in the engraving (Fig. 1). The plant grows rapidly and is
+endowed with much vitality, for it resists changes of temperature to a
+remarkable degree. _Vaucheria_ affords a choice hunting ground to the
+microscopist, for its tangled masses are the home of numberless infusoria,
+rotifers, and the minuter crustacea, while the filaments more advanced in
+age are usually thickly incrusted with diatoms. Here, too, is a favorite
+haunt of the beautiful zoophytes, _Hydra vividis_ and _H. vulgaris_, whose
+delicate tentacles may be seen gracefully waving in nearly every gathering.
+
+
+REPRODUCTION IN VAUCHERIA.
+
+After the plant has attained a certain stage in its growth, if it be
+attentively watched, a marked change will be observed near the ends of the
+filaments. The chlorophyl appears to assume a darker hue, and the granules
+become more densely crowded. This appearance increases until the extremity
+of the tube appears almost swollen. Soon the densely congregated granules
+at the extreme end will be seen to separate from the endochrome of the
+filament, a clear space sometimes, but not always, marking the point of
+division. Here a septum or membrane appears, thus forming a cell whose
+length is about three or four times its width, and whose walls completely
+inclose the dark green mass of crowded granules (Fig. 1, b). These contents
+are now gradually forming themselves into the spore or "gonidium," as
+Carpenter calls it, in distinction from the true sexual spores, which he
+terms "oospores." At the extreme end of the filament (which is obtusely
+conical in shape) the chlorophyl grains retract from the old cellulose
+wall, leaving a very evident clear space. In a less noticeable degree, this
+is also the case in the other parts of the circumference of the cell, and,
+apparently, the granular contents have secreted a separate envelope
+entirely distinct from the parent filament. The grand climax is now rapidly
+approaching. The contents of the cell near its base are now so densely
+clustered as to appear nearly black (Fig. 1, c), while the upper half is of
+a much lighter hue and the separate granules are there easily
+distinguished, and, if very closely watched, show an almost imperceptible
+motion. The old cellulose wall shows signs of great tension, its conical
+extremity rounding out under the slowly increasing pressure from within.
+Suddenly it gives way at the apex. At the same instant, the inclosed
+gonidium (for it is now seen to be fully formed) acquires a rotary motion,
+at first slow, but gradually increasing until it has gained considerable
+velocity. Its upper portion is slowly twisted through the opening in the
+apex of the parent wall, the granular contents of the lower end flowing
+into the extruded portion in a manner reminding one of the flow of
+protoplasm in a living amoeba. The old cell wall seems to offer
+considerable resistance to the escape of the gonidium, for the latter,
+which displays remarkable elasticity, is pinched nearly in two while
+forcing its way through, assuming an hour glass shape when about half out.
+The rapid rotation of the spore continues during the process of emerging,
+and after about a minute it has fully freed itself (Fig 1, a). It
+immediately assumes the form of an ellipse or oval, and darts off with
+great speed, revolving on its major axis as it does so. Its contents are
+nearly all massed in the posterior half, the comparatively clear portion
+invariably pointing in advance. When it meets an obstacle, it partially
+flattens itself against it, then turns aside and spins off in a new
+direction. This erratic motion is continued for usually seven or eight
+minutes. The longest duration I have yet observed was a little over nine
+and one-half minutes. Hassall records a case where it continued for
+nineteen minutes. The time, however, varies greatly, as in some cases the
+motion ceases almost as soon as the spore is liberated, while in open
+water, unretarded by the cover glass or other obstacles, its movements have
+been seen to continue for over two hours.
+
+The motile force is imparted to the gonidium by dense rows of waving cilia
+with which it is completely surrounded. Owing to their rapid vibration, it
+is almost impossible to distinguish them while the spore is in active
+motion, but their effect is very plainly seen on adding colored pigment
+particles to the water. By subjecting the cilia to the action of iodine,
+their motion is arrested, they are stained brown, and become very plainly
+visible.
+
+After the gonidium comes gradually to a rest its cilia soon disappear, it
+becomes perfectly globular in shape, the inclosed granules distribute
+themselves evenly throughout its interior, and after a few hours it
+germinates by throwing out one, two, or sometimes three tubular
+prolongations, which become precisely like the parent filament (Fig 2).
+
+Eminent English authorities have advanced the theory that the ciliated
+gonidium of _Vaucheria_ is in reality a densely crowded aggregation of
+biciliated zoospores, similar to those found in many other confervoid algae.
+Although this has by no means been proved, yet I cannot help calling the
+attention of the members of this society to a fact which I think strongly
+bears out the said theory: While watching a gathering of _Vaucheria_ one
+morning when the plant was in the gonidia-forming condition (which is
+usually assumed a few hours after daybreak), I observed one filament, near
+the end of which a septum had formed precisely as in the case of ordinary
+filaments about to develop a spore. But, instead of the terminal cell being
+filled with the usual densely crowded cluster of dark green granules
+constituting the rapidly forming spore, it contained hundreds of actively
+moving, nearly transparent zoospores, _and nothing else_. Not a single
+chlorophyl granule was to be seen. It is also to be noted as a significant
+fact, that the cellulose wall was _intact_ at the apex, instead of showing
+the opening through which in ordinary cases the gonidium escapes. It would
+seem to be a reasonable inference, I think, based upon the theory above
+stated, that in this case the newly formed gonidium, unable to escape from
+its prison by reason of the abnormal strength of the cell wall, became
+after a while resolved into its component zoospores.
+
+
+WONDERS OF REPRODUCTION.
+
+I very much regret that my descriptive powers are not equal to conveying a
+sufficient idea of the intensely absorbing interest possessed by this
+wonderful process of spore formation. I shall never forget the bright sunny
+morning when for the first time I witnessed the entire process under the
+microscope, and for over four hours scarcely moved my eyes from the tube.
+To a thoughtful observer I doubt if there is anything in the whole range of
+microscopy to exceed this phenomenon in point of startling interest. No
+wonder that its first observer published his researches under the caption
+of "The Plant at the Moment of becoming an Animal."
+
+
+FORMATION OF OTHER SPORES.
+
+The process of spore formation just described, it will be seen, is entirely
+non-sexual, being simply a vegetative process, analogous to the budding of
+higher plants, and the fission of some of the lower plants and animals.
+_Vaucheria_ has, however, a second and far higher mode of reproduction,
+viz., by means of fertilized cells, the true oospores, which, lying dormant
+as resting spores during the winter, are endowed with new life by the
+rejuvenating influences of spring. Their formation may be briefly described
+as follows:
+
+When _Vaucheria_ has reached the proper stage in its life cycle, slight
+swellings appear here and there on the sides of the filament. Each of these
+slowly develops into a shape resembling a strongly curved horn. This
+becomes the organ termed the _antheridium_, from its analogy in function to
+the anther of flowering plants. While this is in process of growth,
+peculiar oval capsules or sporangia (usually 2 to 5 in number) are formed
+in close proximity to the antheridium. In some species both these organs
+are sessile on the main filament, in others they appear on a short pedicel
+(Figs. 3 and 4). The upper part of the antheridium becomes separated from
+the parent stem by a septum, and its contents are converted into ciliated
+motile antherozoids. The adjacent sporangia also become cut off by septa,
+and the investing membrane, when mature, opens: it a beak-like
+prolongation, thus permitting the inclosed densely congregated green
+granules to be penetrated by the antherozoids which swarm from the
+antheridium at the same time. After being thus fertilized the contents of
+the sporangium acquire a peculiar oily appearance, of a beautiful emerald
+color, an exceedingly tough but transparent envelope is secreted, and thus
+is constituted the fully developed oospore, the beginner of a new
+generation of the plant. After the production of this oospore the parent
+filament gradually loses its vitality and slowly decays.
+
+The spore being thus liberated, sinks to the bottom. Its brilliant hue has
+faded and changed to a reddish brown, but after a rest of about three
+months (according to Pringsheim, who seems to be the only one who has ever
+followed the process of oospore formation entirely through), the spore
+suddenly assumes its original vivid hue and germinates into a young
+_Vaucheria_.
+
+
+CHARM OF MICROSCOPICAL STUDY.
+
+This concludes the account of my very imperfect attempt to trace the life
+history of a lowly plant. Its study has been to me a source of ever
+increasing pleasure, and has again demonstrated how our favorite instrument
+reveals phenomena of most absorbing interest in directions where the
+unaided eye finds but little promise. In walking along the banks of the
+little stream, where, half concealed by more pretentious plants, our humble
+_Vaucheria_ grows, the average passer by, if he notices it at all, sees but
+a tangled tuft of dark green "scum." Yet, when this is examined under the
+magic tube, a crystal cylinder, closely set with sparkling emeralds, is
+revealed. And although so transparent, so apparently simple in structure
+that it does not seem possible for even the finest details to escape our
+search, yet almost as we watch it mystic changes appear. We see the bright
+green granules, impelled by an unseen force, separate and rearrange
+themselves in new formations. Strange outgrowths from the parent filament
+appear. The strange power we call "life," doubly mysterious when manifested
+in an organism so simple as this, so open to our search, seems to challenge
+us to discover its secret, and, armed with our glittering lenses and our
+flashing stands of exquisite workmanship, we search intently, but in vain.
+And yet _not_ in vain, for we are more than recompensed by the wondrous
+revelations beheld and the unalloyed pleasures enjoyed, through the study
+of even the unpretentious _Vaucheria_.
+
+The amplification of the objects in the engravings is about 80 diameters.
+
+       *       *       *       *       *
+
+
+
+
+JAPANESE CAMPHOR--ITS PREPARATION, EXPERIMENTS, AND ANALYSIS OF THE
+CAMPHOR OIL.
+
+[Footnote: From the Journal of the Society of Chemical Industry.]
+
+By H. OISHI. (Communicated by Kakamatsa.)
+
+
+LAURUS CAMPHORA, or "kusunoki," as it is called in Japan, grows mainly in
+those provinces in the islands Shikobu and Kinshin, which have the southern
+sea coast. It also grows abundantly in the province of Kishu.
+
+The amount of camphor varies according to the age of the tree. That of a
+hundred years old is tolerably rich in camphor. In order to extract the
+camphor, such a tree is selected; the trunk and large stems are cut into
+small pieces, and subjected to distillation with steam.
+
+An iron boiler of 3 feet in diameter is placed over a small furnace, the
+boiler being provided with an iron flange at the top. Over this flange a
+wooden tub is placed, which is somewhat narrowed at the top, being 1 foot 6
+inches in the upper, and 2 feet 10 inches in the lower diameter, and 4 feet
+in height. The tub has a false bottom for the passage of steam from the
+boiler beneath. The upper part of the tub is connected with a condensing
+apparatus by means of a wooden or bamboo pipe. The condenser is a flat
+rectangular wooden vessel, which is surrounded with another one containing
+cold water. Over the first is placed still another trough of the same
+dimensions, into which water is supplied to cool the vessel at the top.
+After the first trough has been filled with water, the latter flows into
+the next by means of a small pipe attached to it. In order to expose a
+large surface to the vapors, the condensing trough is fitted internally
+with a number of vertical partitions, which are open at alternate ends, so
+that the vapors may travel along the partitions in the trough from one end
+to the other. The boiler is filled with water, and 120 kilogrammes of
+chopped pieces of wood are introduced into the tub, which is then closed
+with a cover, cemented with clay, so as to make it air-tight. Firing is
+then begun; the steam passes into the tub, and thus carries the vapors of
+camphor and oil into the condenser, in which the camphor solidifies, and
+is mixed with the oil and condensed water. After twenty-four hours the
+charge is taken out from the tub, and new pieces of the wood are
+introduced, and distillation is conducted as before. The water in the
+boiler must be supplied from time to time. The exhausted wood is dried and
+used as fuel. The camphor and oil accumulated in the trough are taken out
+in five or ten days, and they are separated from each other by filtration.
+The yield of the camphor and oil varies greatly in different seasons. Thus
+much more solid camphor is obtained in winter than in summer, while the
+reverse is the case with the oil. In summer, from 120 kilogrammes of the
+wood 2.4 kilogrammes, or 2 per cent. of the solid camphor are obtained in
+one day, while in winter, from the same amount of the wood, 3 kilogrammes,
+or 2.5 per cent., of camphor are obtainable at the same time.
+
+The amount of the oil obtained in ten days, _i.e._, from 10 charges or
+1,200 kilogrammes of the wood, in summer is about 18 liters, while in
+winter it amounts only to 5-7 liters. The price of the solid camphor is
+at present about 1s. 1d. per kilo.
+
+The oil contains a considerable amount of camphor in solution, which is
+separated by a simple distillation and cooling. By this means about 20 per
+cent. of the camphor can be obtained from the oil. The author subjected the
+original oil to fractioned distillation, and examined different fractions
+separately. That part of the oil which distilled between 180 deg.-185 deg. O. was
+analyzed after repeated distillations. The following is the result:
+
+    Found.                Calculated as
+                          C_{10}H_{16}O.
+
+C = 78.87                     78.95
+H = 10.73                     10.52
+O = 10.40 (by difference)     10.52
+
+The composition thus nearly agrees with that of the ordinary camphor.
+
+The fraction between 178 deg.-180 deg. C., after three distillations, gave the
+following analytical result:
+
+C = 86.95
+H = 12.28
+    -----
+    99.23
+
+It appears from this result that the body is a hydrocarbon. The vapor
+density was then determined by V. Meyer's apparatus, and was found to be
+5.7 (air=1). The molecular weight of the compound is therefore 5.7 x 14.42
+x 2 = 164.4, which gives
+
+H = (164.4 x 12.28)/100 = 20.18
+                                   or C_{12}H_{20}
+C = (164.4 x 86.95)/100 = 11.81
+
+Hence it is a hydrocarbon of the terpene series, having the general formula
+C^{n}H^(2n-4). From the above experiments it seems to be probable that
+the camphor oil is a complicated mixture, consisting of hydrocarbons of
+terpene series, oxy-hydrocarbons isomeric with camphor, and other oxidized
+hydrocarbons.
+
+
+_Application of the Camphor Oil_.
+
+The distinguishing property of the camphor oil, that it dissolves many
+resins, and mixes with drying oils, finds its application for the
+preparation of varnish. The author has succeeded in preparing various
+varnishes with the camphor oil, mixed with different resins and oils.
+Lampblack was also prepared by the author, by subjecting the camphor oil to
+incomplete combustion. In this way from 100 c.c. of the oil, about 13
+grammes of soot of a very good quality were obtained. Soot or lampblack is
+a very important material in Japan for making inks, paints, etc. If the
+manufacture of lampblack from the cheap camphor oil is conducted on a large
+scale, it would no doubt be profitable. The following is the report on the
+amount of the annual production of camphor in the province of Tosa up to
+1880:
+
+    Amount of Camphor produced.   Total Cost.
+
+1877.......... 504,000 kins.... 65,520 yen.
+1878.......... 519,000   " .... 72,660  "
+1879.......... 292,890   " .... 74,481  "
+1880.......... 192,837   " .... 58,302  "
+
+(1 yen = 2_s_. 9_d_.)
+(1 kin = 1-1/3lb.)
+
+       *       *       *       *       *
+
+
+
+
+THE SUNSHINE RECORDER.
+
+
+McLeod's sunshine recorder consists of a camera fixed with its axis
+parallel to that of the earth, and with the lens northward. Opposite to the
+lens there is placed a round-bottomed flask, silvered inside. The solar
+rays reflected from this sphere pass through the lens, and act on the
+sensitive surface.
+
+[Illustration]
+
+The construction of the instrument is illustrated by the subjoined cut, A
+being a camera supported at an inclination of 56 degrees with the horizon,
+and B the spherical flask silvered inside, while at D is placed the
+ferro-prussiate paper destined to receive the solar impression. The dotted
+line, C, may represent the direction of the central solar ray at one
+particular time, and it is easy to see how the sunlight reflected from the
+flask always passes through the lens. As the sun moves (apparently) in a
+circle round the flask, the image formed by the lens moves round on the
+sensitive paper, forming an arc of a circle.
+
+Although it is obvious that any sensitive surface might be used in the
+McLeod sunshine recorder, the inventor prefers at present to use the
+ordinary ferro-prussiate paper as employed by engineers for copying
+tracings, as this paper can be kept for a considerable length of time
+without change, and the blue image is fixed by mere washing in water;
+another advantage is the circumstance that a scale or set of datum lines
+can be readily printed on the paper from an engraved block, and if the
+printed papers be made to register properly in the camera, the records
+obtained will show at a glance the time at which sunshine commenced and
+ceased.
+
+Instead of specially silvering a flask inside, it will be found convenient
+to make use of one of the silvered globes which are sold as Christmas tree
+ornaments.
+
+The sensitive fluid for preparing the ferro-prussiate paper is made as
+follows: One part by weight of ferricyanide of potassium (red prussiate) is
+dissolved in eight parts of water, and one part of ammonia-citrate of iron
+is added. This last addition must be made in the dark-room. A smooth-faced
+paper is now floated on the liquid and allowed to dry.--_Photo. News._
+
+       *       *       *       *       *
+
+
+
+
+BREAKING OF A WATER MAIN.
+
+
+In Boston, Mass., recently, at a point where two iron bridges, with stone
+abutments, are being built over the Boston and Albany Railroad tracks at
+Brookline Avenue, the main water pipe, which partially supplies the city
+with water, had to be raised, and while in that position a large stone
+which was being raised slipped upon the pipe and broke it. Immediately a
+stream of water fifteen feet high spurted out. Before the water could be
+shut off it had made a breach thirty feet long in the main line of track,
+so that the entire four tracks, sleepers, and roadbed at that point were
+washed completely away.
+
+       *       *       *       *       *
+
+
+A catalogue, containing brief notices of many important scientific papers
+heretofore published in the SUPPLEMENT, may be had gratis at this office.
+
+
+       *       *       *       *       *
+
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+       *       *       *       *       *
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