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diff --git a/11734.txt b/11734.txt new file mode 100644 index 0000000..387f420 --- /dev/null +++ b/11734.txt @@ -0,0 +1,4381 @@ +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. 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