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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. 447, July 26, 1884 + +Author: Various + +Posting Date: October 10, 2012 [EBook #9266] +Release Date: November, 2005 +First Posted: September 16, 2003 + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 447 *** + + + + +Produced by Don Kretz, Juliet Sutherland, and Distributed Proofreaders + + + + + +</pre> + + +<p class="ctr"><a href="images/1a.png"><img src= +"images/1a_th.jpg" alt=""></a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 447</h1> + +<h2>NEW YORK, JULY 26, 1884</h2> + +<h4>Scientific American Supplement. Vol. XVIII, No. 447.</h4> + +<h4>Scientific American established 1845</h4> + +<h4>Scientific American Supplement, $5 a year.</h4> + +<h4>Scientific American and Supplement, $7 a year.</h4> + +<hr> +<table summary="Contents" border="0" cellspacing="5"> +<tr> +<th colspan="2">TABLE OF CONTENTS.</th> +</tr> + +<tr> +<td valign="top">I.</td> +<td><a href="#1">CHEMISTRY.--The Bitter Substance of Hops.--By Dr. +H. BUNGENER. --What gives hops their bitter taste?--Processes for +obtaining hop-bitter acid.--Analysis of the same.</a></td> +</tr> + +<tr> +<td valign="top">II.</td> +<td><a href="#2">ENGINEERING AND MECHANICS.--Improvements in the +Harbor of Antwerp.--With engraving of caisson for deepening the +river.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#3">Progress of Antwerp.--Recent works in the +harbor.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#4">Bicycles and Tricycles.--By C.V. +BOYS.---Advantages of the different machines.--Manner of finding +the steepness of a hill and representing same on a +map.--Experiments on ball bearings.-- The Otto bicycle.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#5">The Canal Iron Works, London.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#6">Marinoni's Rotary Printing Press.--With 2 +engravings.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#7">Chenot's Economic Filter Press.--With +engraving.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#8">Steel Chains without Welding.--Method and machines +for making same.--Several figures.</a></td> +</tr> + +<tr> +<td valign="top">III.</td> +<td><a href="#9">TECHNOLOGY.--Some Economic Processes connected +with the Cloth Making Industry.--By Dr. WM. RAMSAY.--How to save +and utilize soap used in wool scouring.--To recover the indigo from +the refuse.--Extraction of potash from <i>suint</i>.--Use of +bisulphide of carbon.</a></td> +</tr> + +<tr> +<td valign="top">IV.</td> +<td><a href="#10">PHYSICS. ELECTRICITY, ETC.--Thury's Dynamo +Electric Machine. --5 figures.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#11">Breguet's Telephone.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#12">Munro's Telephonic Experiments.--9 +figures.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#13">Apparatus for Maneuvering Bichromate of Potassa +Piles from a Distance.--2 figures.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#14">Magnetic Rotations.--By E.L. VOICE.--1 +figure.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#15">Lighton's Immersion Illuminator.--1 +figure.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#16">Foucault's Pendulum Experiments.--By RICHARD A. +PROCTOR. --4 figures.</a></td> +</tr> + +<tr> +<td valign="top">V.</td> +<td><a href="#17">ARCHITECTURE, ART, ETC.--St. Paul's Vicarage, +Forest Hill, Kent.--2 engravings.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#18">Designs for Iron Gates.--An engraving.</a></td> +</tr> + +<tr> +<td valign="top">VI.</td> +<td><a href="#19">ASTRONOMY.--A New Lunarian.--By Prof. C.W. +MACCORD. --With 3 figures.</a></td> +</tr> + +<tr> +<td valign="top">VII.</td> +<td><a href="#20">GEOLOGY.--Coal and its Uses.--By JAMES +PYKE.--Formation of carboniferous rocks and the coal in the +same.--Processes of nature.--Greatness of this country due to +coal.--Manufacture of gas.--Products of the same.</a></td> +</tr> + +<tr> +<td valign="top">VIII.</td> +<td><a href="#21">NATURAL HISTORY, BOTANY. ETC.--The Wine Fly.--The +egg.--Larva.--Pupa and fly.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#22">The "Potetometer." an Instrument for Measuring +the Transpiration of Water by Plants.--1 figure.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#23">Bolivian Cinchona Forests.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#24">Ferns.--Nephrolepis Davillioides Furcans and +Nephrolepis Duffi. --2 engravings.</a></td> +</tr> + +<tr> +<td valign="top">IX.</td> +<td><a href="#25">PHYSIOLOGY, HYGIENE, ETC.--The Upright Attitude +of Mankind. --Review of a lecture by Dr. S.V. CLEVENGER, in which +he tries to prove that man must have originated from a four footed +being.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#26">Our Enemies, the Microbes.--Affections caused by +the same.-- Experiments of Davaine, Pasteur, and others.--How to +prevent bacterides from entering the body.--5 figures.</a></td> +</tr> + +<tr> +<td valign="top">X.</td> +<td><a href="#27">BIOGRAPHY.--Gaston Plante, the Scientist.--With +portrait</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#28">Warren Colburn, the American +Mathematician.</a></td> +</tr> +</table> + +<hr> +<p><a name="2"></a></p> + +<h2>IMPROVEMENTS IN THE HARBOR OF ANTWERP.</h2> + +<p>The harbor of Antwerp, which, excepting those of London and +Liverpool, is the largest in Europe, has been improved wonderfully +during the last decade. Before 1870 it was inferior to the harbor +at Havre, but now it far surpasses the same. The river Scheldt, +which is about 1,500 ft. wide, was badgered out up to the vertical +walls of the basin, so that the largest ships can land at the +docks. The river was deepened by the use of caissons, in the lower +parts of which the workmen operated in compressed air. The annexed +cut shows that part of one of the caissons which projects above the +surface of the water. The depth of the river at low tide is about +26 ft., and at high tide about 39 ft. Some of the old sluices, +channels, basins, etc., which were rendered useless by the +improvements made in the river Scheldt have been filled up, and +thereby the city has been enriched by several handsome and elegant +squares.--<i>Illustrirte Zeitung</i>.</p> + +<hr> +<p><a name="3"></a></p> + +<h2>PROGRESS OF ANTWERP.</h2> + +<p>Antwerp is now the chief port on the Continent. Since 1873 the +progress has continued, and made very rapid advances. In 1883 the +tonnage of the port reached 3,734,428 registered tons. This +marvelous development is partly due to the position of Antwerp as +the embarking point from the Continent of Europe to America, and +partly also to the recent additions and changes which have been +carried out there, and which, now nearly completed, have made this +cosmopolitan port one of the best organized in the world. This is +so well known that vessels bound for Switzerland with a cargo of +corn from Russia pass Marseilles and go two thousand miles out of +their way for the purpose of unloading at Antwerp. No other port, +in fact, offers the same facilities. There is not another place in +the world where fifty vessels of 3,000 tons can come alongside as +easily as the penny boats on the Thames run into the landing.</p> + +<p class="ctr"><a href="images/1b.png"><img src= +"images/1b_th.jpg" alt= +"CAISSONS FOR DEEPENING THE RIVER AT ANTWERP."></a></p> + +<p class="ctr">CAISSONS FOR DEEPENING THE RIVER AT ANTWERP.</p> + +<p>Since the opening of the St. Gothard Tunnel nearly all the +alimentary provisions that Italy sends to the British Isles pass +through Antwerp. In 1882 82,000,000 eggs and 30,000 pounds of fruit +were shipped there for England. The greater part of these came from +Italy. Antwerp has become also an important port for emigrants; +35,125 embarked in 1882, out of which number 3,055 were bound for +New York. The city was always destined, from its topographical +position, to be at the head of a very considerable traffic; +political reasons alone for many years prevented this being the +case. These have happily now disappeared, and, since 1863, when the +"Scheldt was liberated," the progress of commerce has been more +rapid than even the most ardent Antwerp patriot dared hope. At that +date the toll of 1s. 11d. on all vessels going up the river, and of +7½d. on vessels going down, was abolished, and reforms were +introduced among the taxes on the general navigation; the tax on +tonnage in the port itself was abolished, and the pilot tax was +lowered. The results of these measures became immediately apparent. +Traffic increased with such rapidity that in 1876 the crowding on +the quays was such that the relation of the tonnage to the length +of the quay was about 270 tons per yard, which is four times as +great as at Liverpool.</p> + +<p>A few words now, briefly, as to the nature of the important +works[1] completed at Antwerp. They were commenced in 1877, and +have opened for the port an era of prosperity such as was never +experienced even during the sixteenth century, the zenith of her +splendor. These works have cost £4,000,000, and have +necessitated the employment of 12,000 tons of wrought iron, of +490,000 cubic yards of brickwork and concrete, of 32,000 cubic +yards of masonry, and of more than 3,300,000 cubic yards of +earthwork in filling and dredging, etc. The quay walls run the +whole length of the town, a distance of rather more than two miles. +It rests on a foundation laid without timber footings, and giving a +depth of twenty-six feet at low water, sufficient drawing for the +largest ships afloat. Beyond this wall are the real quays, which +consists of first a line of rails reserved for hydraulic cranes +serving to unload vessels and deposit their cargo railway trucks; +secondly, a second line of rails parallel with the first, on which +these trucks are stationed; thirdly, sheds extending toward the +town for a width of one hundred and fifty feet, and covered with +galvanized iron sheetings. A third line of rails parallel with the +two others runs from end to end of these sheds, and a number of +lines placed transversely with this one connect it by means of +spring bridges with, fourthly, four more lines also parallel with +the quays, whence the goods start for the different stations, and +thence to their destinations. The total width of these immense +constructions is about three hundred and twenty feet. Such is their +magnitude that about six hundred houses had to be pulled down to +make place for them. A railing running along their entire length +cuts them off from the town.</p> + +<p>[Transcribers note 1: changed from 'words']</p> + +<p>During the course of last year 4,379 vessels entered the port of +Antwerp, gauging a total of 3,734,428 tons, which places Antwerp, +as I have already stated, at the head of European ports. In 1882 +the tonnage of Havre was only 2,200,000, that of Genoa 2,250,000, +and of Bilboa 315,000, owing to its iron ore exports. Among the +English ports a few only exceed Antwerp. London is still the first +port in the world, with a tonnage of 10,421,000 tons, and Liverpool +the second, with 7,351,000 tons; Newcastle follows with 6,000,000 +tons, also in excess of Antwerp, but both Hull and Glasgow are +below, with respectively 1,875,000 and 2,110,000 tons.--<i>Pall +Mall Gazette</i>.</p> + +<hr> +<p><a name="4"></a></p> + +<h2>BICYCLES AND TRICYCLES.</h2> + +<p>[Footnote: A recent lecture before the Society of Arts, +London.]</p> + +<h3>By C.V. BOYS.</h3> + +<p>The subject of this paper is one of such wide interest, and of +such great importance, that it is quite unnecessary for me to make +any apology for bringing it to your notice. Exactly two months ago, +I had the honor of dealing with the same subject at the Royal +Institution. On that occasion I considered main principles only, +and avoided anything in which none but riders were likely to take +an interest, or which was in any way a matter of dispute. As it may +be assumed that the audience here consists largely of riders, and +of those who are following those matters of detail, the +elaboration, simplification, and perfection of which have brought +the art of constructing cycles to its present state of perfection, +I purpose treating the subject from a totally different point of +view. I do not intend, in general, to describe anything, assuming +that the audience is familiar with the construction of the leading +types of machines, but rather to consider the pros and cons of the +various methods by which manufacturers have striven to attain +perfection. As a discussion on the subject of this paper will +doubtless follow--and I hope makers or riders of every class of +machine will freely express their opinion, for by so doing they +will lend an interest which I alone could not hope to awaken--I +shall not consider it necessary to assume an absolutely neutral +position, which might be expected of me if there were no +discussion, but shall explain my own views without reserve.</p> + +<p>The great variety of cycles may be grouped under the following +heads:</p> + +<pre> + 1. The Bicycle unmodified. + 2. The Safety bicycle, a modification of 1. + 3. The Center-cycle. + 4. The Tricycle, which includes five general types: + (a.) Rear steerer of any sort. + (b.) Coventry rotary. + (c.) Front steerer of any sort (except e). + (d.) Humber pattern. + (e.) The Oarsman. + 5. Double machines: sociables and tandems. + 6. The Otto. +</pre> + +<p>It is perfectly obvious that not one machine is superior to all +others in every respect, for if that were the case, the rest would +rapidly become extinct. Not one shows any signs of becoming +extinct, and, therefore, it may be assumed that each one possesses +some points in which it is superior to others, the value of which +is considered by its riders to far outweigh any points in which it +may be inferior. The widely varying conditions under which, and +purposes for which, machines are used and the very different +degrees of importance which differently constituted minds attach to +the peculiarities of various machines, will, probably, prevent any +from becoming extinct. Nevertheless, the very great advantages +which some of these possess over others will, no doubt, in time +become evident by the preponderance of the better class of +machines.</p> + +<p>The bicycle, which surpasses all other machines in simplicity, +lightness, and speed, will probably, for these reasons, always +remain a favorite with a large class. The fact that it requires +only one track places it at a great advantage with respect to other +machines, for it is common for a road which is unpleasant from mud +or stones to have a hard, smooth edge, a kind of path, where the +bicyclist can travel in peace, but which is of little advantage to +other machines. Again, the bicycle can be wheeled through narrow +gates or door ways, and so kept in places which are inaccessible to +tricycles. One peculiarity of the bicycle, and to a certain extent +of the center-cycle, is that the plane of the machine always lies +in the direction of the resultant force, that the machine leans +over to an amount depending on the velocity and the sharpness of +the curve described. For this reason all lateral strain on the +parts is abolished, and if we except the slipping away of the wheel +from under the rider, which can hardly occur on a country road, an +upset from taking a curve too quickly is impossible. This leaning +to either side by the machine and rider gives rise to that +delightful gliding which none but the bicyclist or the skater can +experience. In this respect the bicycle has an enormous advantage +over any machine, tricycle or Otto, which must at all times remain +upright, and which must, therefore, at a high speed, be taken round +a curve with discretion.</p> + +<p>The perfect and instantaneous steering of the bicycle, combined +with its narrowness, counteract, to a great extent, the advantage +which the tricyclist has of being able to stop so much more +quickly, for the bicyclist can "dodge" past a thing for which the +rider of the three-wheeler must pull up. In one other respect the +bicyclist has an advantage which, though of no real importance, has +great weight with many people. The bicycle well ridden presents a +picture of such perfect elegance that no one on anything else need +expect to appear to advantage in comparison.</p> + +<p>The chief disadvantage of the bicycle is the fact that a rider +cannot stop for any purpose, or go back a little, without +dismounting. For town riding, where a stoppage is frequently +necessitated by the traffic, this perpetual mounting and +dismounting is not only tiresome, but wearying, so much so that few +bicyclists care to ride daily in town.</p> + +<p>The position of the rider on a bicycle, with respect to the +treadles, is by no means good, for if he is placed sufficiently far +forward to be able to employ his weight to advantage without +bending himself double, he will be in so critical a position that a +mere touch will send him over the handles. He has, therefore, to +balance stability and safety against comfort and power; the more +forward he is, the more furiously he can drive his machine, and the +less does he suffer from friction and the shaking of the little +wheel; the more backward he is, the less is he likely to come to +grief riding down hill, or over unseen stones. The bicyclist is no +better off than the rider of any other machine with a little wheel, +the vibration from which may weary him nearly as much as the work +he does. The little wheel as a mud-throwing machine engine is still +more effective on the bicycle than it is on any tricycle, for in +general it is run at a higher speed.</p> + +<p>I now come to the usual complaint about the bicycle. There is a +fashion just now to call it dangerous and the tricycle safe. But +the difference in safety has been much exaggerated. The bicyclist +is more likely to suffer from striking a stone than his friend on +three wheels, but then he should not strike one where the +tricyclist would strike a dozen. Properly ridden, neither class of +machine can be considered dangerous; an accident should never +happen except it be due to the action of others. People, carts, +cattle, and dogs on the road are liable to such unexpected +movements, that the real danger of the cyclist comes from the +outside; to danger from absolute collapse, due to a hidden flaw in +the materials employed, every one is liable, but, the bicyclist +more remotely than the tricyclist, owing to the greater simplicity +of his machine. The bicyclist, though he has further to fall in +case of an accident from any of these causes, is in a better +position than the tricyclist, for he is outside instead of inside +his machine; he can in an instant get clear.</p> + +<p>It would appear that many tricyclists consider accidents of the +kind next to impossible, for in several machines the rider is so +involved that an instantaneous dismount without a moment's notice, +at any speed, is absolutely impossible. There remains one +objection, which, however, should be of next to no importance--the +difficulty of learning the bicycle prevents many from taking to the +light and fast machine, because they are afraid of a little +preliminary trouble.</p> + +<p>The chief objections to the bicycle, then, are the liability of +the rider to go over the handles, the impossibility of stopping +very quickly, and the inability to remain at rest or go backward, +and the difficulty of learning.</p> + +<p>The first two of these are, to a large extent, overcome in the +safety bicycles, but not without the introduction of what is in +comparison a certain degree of complication, or without the loss of +the whole of the grace or elegance of the bicycle. On almost all of +these safety bicycles the rider is better placed than on the +unmodified bicycle, but though safer, I do not think bicyclists +find them complete in speed, though, no doubt, they are superior in +that respect to the tricycle. Though they do not allow the rider to +stop without dismounting, the fatigue resulting from this cause is +less than it is with a bicycle, owing to the fact that with the +small machines the rider has so small a distance to climb. Of these +machines, the Extraordinary leaves the rider high up in the air on +a full-sized wheel, but places him further back and more over the +pedals. The motion of these is peculiar, being not circular, but +oval, a form which has certain advantages.</p> + +<p>In the Sun and Planet and Kangaroo bicycles a small wheel is +"geared up," that is, is made to turn faster than the pedals, so as +to avoid the very rapid pedaling which is necessary to obtain an +ordinary amount of speed out of a small wheel. In each of these the +pedals move in a circular path, and their appearance is in +consequence less peculiar than that of the Facile, which, in this +respect, does not compare favorably with any good machine. The +pedal motion on the Facile is merely reciprocating. Riders of +machines where circular motion is employed, among them myself, do +not believe that this reciprocating motion can be so good as +circular, but I understand that this view is not held by those who +are used to it. Of course, the harmonic motion of the Facile pedal +is superior to the equable reciprocating motion employed in some +machines where speed is an object, especially with small +wheels.</p> + +<p>If I have overlooked anything typical in the modified bicycle +class, I hope some one will afterward supply the omission, and +point out any peculiarities or advantages.</p> + +<p>That very peculiar machine, the center-cycle, seems to combine +many of the advantages of the bicycle and tricycle. On it the rider +can remain at rest, or can move backward; he can travel at any +speed round curves without an upset being possible; he can ride +over brickbats, or obstructions, not only without being upset, but, +if going slowly, without even touching them. As this machine is +very little known, a few words of explanation may be +interesting.</p> + +<p>In the first place, the rider is placed over the main wheel, as +in the bicycle, but much further forward. There are around him, on +or near the ground, four little wheels, two before and two behind, +supported in a manner the ingenuity of which calls for the utmost +admiration. Turning the steering handle not only causes the front +and rear pairs to turn opposite ways, but owing to their swiveling +about an inward pointing axis, the machine is compelled to lean +over toward the inside of the curve; not only is this the case, but +each pair rises and falls with every inequality of the road, if the +rider chooses that they run on the ground; but he can, if he +pleases, arrange that in general they ride in the air, any one +touching at such times as are necessary to keep him on the top of +the one wheel, on which alone he is practically riding. He can, if +he likes, at any time lift the main wheel off the ground and run +along on the others only. The very few machines of the kind which I +have seen have been provided with foot straps, to enable the rider +to pull as well as push, which is a great advantage when climbing a +hill, but this is on every machine except the Otto, of which I +shall speak later, considered a dangerous practice.</p> + +<p>Some of the objections to the bicycle to which I have referred +were sufficient to prevent many, especially elderly men, from +dreaming of becoming cyclists. So long as the tricycle was a crude +and clumsy machine, there was no chance of cycling becoming a part, +as it almost is and certainly soon will be, of our national life. +The tricycle has been brought to such a state of perfection that it +is difficult to imagine where further progress can be made.</p> + +<p>Perhaps it will be well to mention what is necessary in order +that a three-wheeled machine may be made to roll freely in a +straight line, and also round curves. At all times each wheel must +be able to travel in its own plane in spite of the united action of +the other two. To run straight, the axes of all the wheels must +obviously be parallel. To run round a curve, the axis of each must, +if continued, pass through the center of curvature of the curve. If +two wheels have a common axis, the intersection of the two lines +forming the axes can only meet in one point. To steer such a +combination, therefore, the plane of the third wheel only need be +turned. If the axis of no two are common, then the planes of two of +the wheels must be turned in order that the three axes may meet in +a point.</p> + +<p>Not only does free rolling depend on the suitable direction of +the planes of the wheels, each wheel must be able to run at a speed +proportional to its distance from the point of intersection of the +three axes, i.e., from the ever-shifting center of curvature.</p> + +<p>The most obvious way, then, of contriving a three wheeler is to +drive one wheel, steer with another, and leave the third, which +must be opposite the driver, idle. The next in simplicity is to +drive with one wheel, and steer with the other two, having one in +front and the other behind. So far then, the single driving +rear-steerer and the Coventry rotary pattern are easily understood. +The evils of single driving, minimized, it is true, to a large +extent, in the Coventry rotary, have led to the contrivance of +means by which a wheel on each side may be driven without +interfering with their differential motion in turning a corner.</p> + +<p>Three methods are commonly used, but as only two are employed on +tricycles, I shall leave the third till I come to the special +machine for which it is necessary. The most easy to understand is +the clutch, a model of which I have on the table. If each main +wheel is driven by means of one of these, though compelled to go +forward by the crankshaft, it is yet free to go faster without +restraint. By this means "double driving" is effected in several +forms of tricycle.</p> + +<p>Differential gear, which is well understood, and of which there +are several mechanically equivalent forms, divides the applied +driving power, whether forward or backward, between the main +wheels, equally if the gear is perfect, unequally if imperfect. To +understand the effect of the two systems of driving, and of single +driving, let us place on grooves a block which offers resistance to +a moving force. If we wish to move it, and apply our force at the +end of one side, it will tend to turn round as well as move +forward, and much friction will be spent on the guides by their +keeping it straight.</p> + +<p>This is the single driver. If, instead of applying force at one +side, we push the block bodily forward by a beam moving parallel to +itself, then so long as the guides are straight no strain will be +put upon them, even though one side of the block is resisted more +than the other; if, however, the guides compelled the block to +travel round a curve, then the power, instead of being divided +between the two sides in such proportion as is necessary to relieve +the guides of all strain, is suddenly applied only to the inside, +and the effect is that of a single driver only. This is the clutch. +Lastly, if the last-mentioned beam, instead of being pushed along +parallel to itself, were pivoted in the middle, and that pivot only +pushed, the same power would be applied to each side of the block, +and no strain would be thrown on the guides, whether straight or +curved, so long as the resistance opposed to the block on the two +sides were equal; if, however, one side met with more resistance +than the other, then the guides would have to keep the block +straight. This is the differential gear.</p> + +<p>I have assumed that in the last case the force was applied to +the middle of the beam; this corresponds to every evenly-balanced +gear. In the gear employed by Singer, which is not evenly balanced, +but which derives its good qualities from its simplicity, the same +effect is produced as if the beam were pivoted on one side of the +center instead of on the center. Thus, though both sides are +driven, one is driven more than the other. On the whole, there is +no doubt that the balanced gear gives a superior action to the +clutch, for except when the two sides of the machine meet with very +different resistance, and then only when running straight, the +clutch will not compare with the other. The clutch also gives rise +to what is considered by most riders a grave defect, the inability +to back treadle, while the free pedal, which is an immediate +consequence, is considered by others a luxury.</p> + +<p>On the other hand, this same free pedal can be obtained on +differentially driven machines to which speed and power gear have +been applied.</p> + +<p>Of the relative merits of different forms of differential gear +there is little to be said. Perhaps it will not be thought I am +unduly thrusting myself forward, if I refer to a scheme of my own, +in which no toothed wheels are employed, but in which two conical +surfaces are driven by a series of balls lying in the groove +between them, and jambed against them by a recessed ring.</p> + +<p>I have here a large wooden diagrammatic model, and a small +working model in steel, which shows that the new principle employed +is correct, namely, that a ball while jambed is free to turn, or if +turning is able to jamb. All Humbers, and most front steerers, +employ differential gearing; in some front steerers the clutch of +necessity is used.</p> + +<p>Neglecting for the present the different modes of transmitting +power from the pedals to the main wheels, it is possible now to +consider the four typical builds of tricycle. The only advantage +that a rider can find in a rear-steerer is the open front, so that +in case of accident he can more easily clear himself of his +machine; as I have already remarked, this power of instantly +escaping seems to be considered by many as of no importance.</p> + +<p>In a rear-steerer which has not an open front, whether driven by +a clutch or by differential gear, I fail to discover any good +quality. The steering of a rear-steerer is so very uncertain, that +such machines cannot safely be driven at anything like a high +speed, because any wheel meeting with an obstruction will, by +checking the machine, diminish the weight on the steering wheel +just at the time when a greater weight than usual should be +applied. It is for the corresponding reason that the steering of a +front-steerer is so excellent; the more the machine is checked by +obstruction, by back treading, or by the brake, the greater is the +weight on the front wheel.</p> + +<p>For shooting hills, or for pulling up suddenly, no machine of +any kind will compare with a good front-steerer. In all respects it +is superior to the rear-steerer if we except the open front, but +against this may be set the fact that on many the rider can mount +from behind, or can dismount in the same manner while the machine +is in motion. Experience shows that the front-steerer is for +general excellence, safety, easy management, and light-running, the +best all-round tricycle that is to be had.</p> + +<p>The Humber build, which departs less from the ordinary bicycle +than any othar, is far superior to all others for speed; it is, +however, somewhat difficult to manage, for the steering is not only +delicate, but critical, requiring constant care lest a stone or +other obstruction should take the rider unawares, and steer the +machine for him.</p> + +<p>The control which a skillful rider of the Humber has over his +machine is wonderful; the elegance of the machine among tricycles +is unequaled. So great a favorite is this form, especially among +the better class of riders, that almost every firm have brought out +their own Humber, each with a distinguishing name.</p> + +<p>The only improvement or change, whichever it may be, that has +been made by others with which I am acquainted, is the triple +steering, in which the hind wheel moves the opposite way to the +others. The corresponding change in the bicycle was soon discarded; +I do not know what advantage can result from the increased delicacy +of steering here. I should have thought it delicate enough +already.</p> + +<p>One noticeable change in the front-steering tricycle, which has +been largely made, lately, is the substitution of central for side +gearing, in consequence of which bicycle cranks can be employed, +instead of the cranked axle, with its fixed throw. This gives an +appearance of lightness which the older types of machine do not +possess.</p> + +<p>I now come to that very difficult and all-important subject, the +method of transmitting power from the body of the rider to the main +axle. Next to the structural arrangement, this is most important in +distinguishing one type of machine from another.</p> + +<p>The first to which I shall refer is the direct action employed +on the National and the Monarch tricycles. It is obvious that by +having no separate crank shaft, much greater simplicity and +cheapness and less friction are attained than can be possible when +the extra bearings and gear generally used are employed. In this +respect the direct action machines undoubtedly have an advantage, +but an advantage of any kind may be too dearly bought, as it +certainly is here.</p> + +<p>In the first place, the direct action can only be applied to a +rear-steering, clutch-driven machine, or single driver, for if the +wheels were not free to run ahead, it would be impossible to go +round a curve. In the second place, the rider must be placed at +such a height for his feet to work on the axle that the machine, of +necessity, is very unstable, and is likely to upset if ridden +without great caution round a curve. Thirdly, to diminish as far as +possible this last objection, miserable little wheels must be +employed, which cannot be geared up, that is, made to travel faster +than the treadles, and so be equivalent to larger wheels. +Therefore, though it is likely that at such low speeds only as it +is safe to run such a machine it may move more easily than a +machine of a recognized type, and though direct action would +undoubtedly be advantageous if it did not entail defects of a most +serious order of magnitude, we may dismiss this at once from our +consideration. It is true that in the Monarch a few inches of +height are gained by the hanging pedals, but I question very much +whether one machine is much better than the other.</p> + +<p>The chain which is used on almost every make of machine cannot +be considered perfect; it is, on the whole, a dirty and noisy +contrivance, giving rise to friction where the links take and leave +the teeth of the pulleys; stretching, or rather lengthening, by +wear, and, finally, allowing back lash, which is most unpleasant. +In spite of all this, it affords a convenient and reliable means of +transmitting power, which is applicable to every type of tricycle, +except one.</p> + +<p>Instead of a chain, an intermediate or idle wheel has been +tried, but this has not been found advantageous. The intermediate +wheel has been removed, and the crank and wheel pulley allowed to +gear directly together, making reverse motion of the feet +necessary, and possibly reducing friction.</p> + +<p>The crank and connecting rod are employed in some machines. If +there are two only, they must not be placed in opposite positions, +but be fixed at an angle, so that there are times when each rod is +under compression, a strain which delicate rods cannot stand. In +the three-throw crank, employed in the Matchless tricycle, this +objection is obviated, for one, at least, is at all times in such a +position as to be in tension. The objection to the crank is the +fact that it weakens the shaft, and that it can only be used with a +clutch, not with a differential gear.</p> + +<p>The most silent, neatest, and cleanest driver, the one of which +the working friction is least, is the endless steel band, so well +known in connection with the Otto bicycle. This is not, as far as I +am aware, employed on any tricycle, makers probably fearing lest it +should slip. The Otto shows that it can safely be employed.</p> + +<p>I have devised a scheme, of which I now show a model, which +seems to me to be free from the objections which may be urged +against other methods; but I, of course, cannot be considered in +this respect a judge. Eccentrics are well known as equivalent to +cranks, but if used in the same way, with a connecting rod, either +fatal friction or enormous ball-bearings would be necessary. +Instead of these, I connect two pair of equal eccentrics by an +endless band embracing each, so that the band acts like a +connecting rod without friction, and, at the same time, acts by its +turning power as on the Otto, thus making two eccentrics sufficient +instead of three, and carrying them over the dead points.</p> + +<p>There is one more system of transmitting power employed on a few +machines. In these, a band or line passes over the circumference of +a sector or wheel, and the power is directly applied to it. The +motion of the feet in the omnicycle, and of the hands and body in +the Oarsman, is therefore uniform. There would be no harm in this +if it were not for the starting and the stopping, which cannot be +gradual and at the same time effective in machines of this type. +For this reason, a high speed cannot be obtained; nevertheless, +these machines are better able to climb hills than are tricycles +with the usual rotary motion, for, at all parts of the +stroke--which may be of any length that the rider chooses--his +driving power on the wheels is equal. The ingenious expanding drums +on the omnicycle make this machine exceptionally good in this +respect, for increased leverage is effected without increased +friction, which is the result of "putting on the power" in some of +the two-speed contrivances.</p> + +<p>Having spoken of the Oarsman tricycle, I must express regret +that I have not been able to find an opportunity to ride on or with +the machine, so that I cannot from observation form an opinion of +its going qualities. There can be no doubt that the enormous amount +of work that can be got from the body in each stroke on a sliding +seat in a boat must, applied in the same manner on the Oarsman +tricycle, make it shoot away in a surprising manner; whether such +motion, when continued for hours, is more tiring than the ordinary +leg motion only, I cannot say for certain, but I should imagine +that it would be. The method by which the steering is effected by +the feet, and can with one foot be locked to a rigidly straight +course, is especially to be admired.</p> + +<p>There is much difference of opinion with respect to the most +suitable size for the wheels of machines. Except with certain +machines, this has nothing to do with the speed at which the +machine will travel at a given rate of pedaling, for the wheels may +be geared up or down to any extent, that is made to turn more +quickly or slowly than the cranks. Thus the most suitable speeding +is a separate question, and must be treated by itself.</p> + +<p>Large wheels are far superior to small wheels in allowing +comfortable, easy motion, a matter of considerable importance in a +long journey. They are also far better than small for running over +loose or muddy ground, for with a given weight upon them they sink +in less, from the longer bearing they present, and this, combined +with their less curvature, makes the everlasting ascent which the +mud presents to them far less than with a smaller wheel. On the +other hand, the large wheel is heavier, and suffers more from air +resistance than the small wheel. For racing purposes a little +wheel, geared up of course, is certainly better than a high wheel; +for comfortable traveling, and in general, the high wheel is +preferable. Though this is certainly the case, it does not follow +that large wheels are worth having on a machine when there is +already one little wheel. If the rider is to be worried with the +evils of a little wheel at all, it is possible that any advantage +which large wheels would give him would be swamped by the vibration +and mud-sticking properties of the small steering wheel. One firm, +in their endeavors to minimize these evils, have designed machines +without any very small wheels; all three wheels are large, and a +steadier and more comfortable motion no doubt results.</p> + +<p>High and low gearing are the natural sequel to high and low +wheels. Of course the lower the gearing the greater is the +mechanical advantage in favor of the rider when meeting with much +resistance, whether from wind, mud, or steepness of slope. In spite +of this, for some reason which I cannot divine, the machines with +excessively low gear do not seem to obtain so great an advantage in +climbing hills as might be expected. To make such a machine travel +at a moderate speed only, excessively rapid pedaling is necessary, +and the rider is made tired more by the motion of his legs than by +any work he is doing. The slow, steady stroke by which a rider +propels a high-geared machine is far more graceful and less +wearying than the furious motion which is necessary on a low-geared +machine. The height up to which the driving-wheels are usually +geared may be taken as an indication of the ease with which any +class of machines runs. A rider on a low-geared machine can start +his machine much more quickly than an equal man on one that has +high gearing, and therefore in a race he has an advantage at first, +which he speedily loses as his rapid pedaling begins to tell. For +ordinary riding the slight loss of time at starting is a matter of +no importance whatever.</p> + +<p>There are several devices which enable us to obtain the +advantages of high and low gearing on the same machine, which at +the same time give the rider the benefit of a free pedal whenever +he wishes. On some single driving rear-steering tricycles the +connection on one side is for speed, and that on the other for +power, either being in action at the wish of the rider, or both +speed and power combinations are applied on the same side. To drive +with a power gear a single wheel only seems to me to be the height +of folly; in my opinion no arrangement of this type is worthy of +serious attention. Among the better class of machines there are +three methods by which this change is effected--first, that +employed on the omnicycle, to which I have already referred; +secondly, an epicyclic combination of wheelwork which moves as one +piece when set for speed, thus adding nothing to the working +friction except by its weight, but which works internally when set +for power, thus reducing to a small extent, by the additional +friction, the gain of power which the rider desires; thirdly, a +double set of chains and pulleys, each set always in movement, so +that, whether set for speed or power, there is rather more friction +than there would be if there were no additional chains, but these +are free from that increased friction due to toothed wheel gearing, +from which the epicyclic contrivances suffer only when set for +power. There is much difference of opinion whether any of these +arrangements are worth carrying, for perhaps nine miles, for the +sake of any advantage that may be obtained in the tenth. It is on +this account that the drums on the omnicycle are so excellent; +whether expanded or not, there is, on their account, no loss of +work whatever, for there is no additional friction. The subject of +these two speed gears will, I hope, be discussed; it is one which, +though not new, is coming more to the front, and about which much +may be said.</p> + +<p>Having now dealt with the means by which tricycles are made to +climb hills more easily, I wish to leave the subject of bicycles +and tricycles altogether for a few minutes, to say a few words +which may specially interest those who are fond of trying their +power in riding up our best known hills. The difficulty of getting +up depends to a large extent on the surface and on the wind, but +chiefly on the steepness. The vague manner in which one hill is +compared with another, and the wild ideas that many hold who have +not made any measurements, induces me to describe a method which I +have found specially applicable for the measurement of steepness of +any hill on which a cyclist may find himself, and also a scheme for +the complete representation of the steepness and elevation of every +part of a hill on a map so as to be taken in at a glance. The force +required to move the thing up a slope is directly proportional not +to the angle, but to the trigonometrical sine of that angle. To +measure this, place the tricycle, or Otto--a bicycle will not stand +square to the road, and therefore cannot be used--pointing in +direction at right angles to the slope of the hill, so that it will +not tend to move. Clip on the top of the wheel a level, and mark +that part of the road which is in the line of sight. Take a string +made up of pieces alternately black and white, each exactly as long +as the wheel is high, and stretch it between the mark and the top +of the wheel. If there are n pieces of string included, the slope +is 1 in n, for by similar triangles the diameter of the wheel is to +the length of the string as the vertical rise is to the distance on +the road. This gives the average steepness of a piece sufficiently +long to be worth testing, because an incline only a few feet in +length, of almost any steepness, can be mounted by the aid of +momentum.</p> + +<p>There is only one process, with which I am acquainted, which +supplies a method of representing on a map the steepness of a road +at every part. Contours, of course, show how far one has to go to +rise 50 or 100 feet, but as to whether the ascent is made uniformly +or in an irregular manner, with steep and level places, they tell +us nothing. Let the course of a road be indicated by a single line +where it is level, and by a pair of lines where inclined. Let the +distance between the lines be everywhere proportional to the +steepness, then the greatest width will show the steepest part, and +an intermediate width will show places of intermediate steepness; +the crossing of the lines, which must be distinguishable from one +another, will show where the direction of the slope changes. +Further, the size of the figure bounded by the two lines will show +the total rise; a great height being reached only by great +steepness or by great length, a large figure being formed only by +great width or by great length. Those who are mathematically +inclined will recognize here that I have differentiated the curve +representing the slope of the bill, and laid the differential curve +down in plan.</p> + +<p>Having wandered off my subject, I must return to more mechanical +things, and give the results of some experiments which I have made +on the balls of ball bearings. There is no necessity to argue the +case of ball vs. plain bearings, the balls have so clearly won +their case, that it would be waste of time to show why. Of the wear +of the twelve balls forming one set belonging to the bearings of +the wheels of my Otto, I have on a previous occasion spoken; I may, +however, repeat that in running 1,000 miles, the twelve balls lost +in weight only 1/20.8 grain, or each ball lost only 1/250 grain. +The wear of the surface amounted to only 1/158000 inch; at the same +rate of wear, the loss in traveling from here to the moon would +amount to only 1/34.3 of their weight. I examined each ball every +200 miles, and was surprised to find that on the whole the wear of +each, during each journey, varied very little. The balls +experimented on were a new set obtained from Mr. Bown. I also had +from him one ball of each of each of the following sizes 3, 4, 5, +6, and 7 16ths of an inch in diameter, as I was curious to know +what weight they would suppport without crushing. As as preliminary +experiment, I placed a spare 5/16 ball between the crushing faces +of the new testing machine at South Kensington, and applied a +gradually increasing force up to 7 tons 9½ cwt., at which it +showed no signs of distress. On removing it I found that it had +buried itself over an angle of about 60° in the hard steel +faces, faces so hard that a file would not touch them. Those marks +will be a permanent record of the stuff of which the ball was made. +The ball itself is sealed in a tube, so that any one who is curious +to see it can do so. Finding that the crushing faces were not +sufficiently hard, I made two anvils of the best tool steel, and +very carefully hardened them. These, though they were impressed +slightly, were sufficiently good for the purpose. In the following +table are the results of the crushing experiments:</p> + +<p>3/16 ball at 2 tons 13 cwt. did not break, but crushed on +removing part of the weight.</p> + +<p>¼ ball at 3 tons 15 cwt. did not break, but crushed on +removing part of the weight.</p> + +<p>5/16 ball at 4 tons 9 cwt. broke.</p> + +<p>3/8 ball at 8 tons 6 cwt. did not break, crushed under another +120 lb.</p> + +<p>7/16 ball crushed before 3 tons, with which I was starting, had +been applied. Examination showed that the steel bar of which it was +made had been laminated.</p> + +<p>These experiments do not tell much of importance; they are +curious, and perhaps of sufficient interest to bring before your +notice. The fragments are all preserved in tubes, and labeled, so +that any one who likes to see them can do so.</p> + +<p>Of the advantage which a machine which will collapse or fold up +when desired, but retain its form on the road, offers in +convenience, it is unnecessary for me to speak.</p> + +<p>Of double machines, the Rucker tandem bicycle seems to me to be +in every respect the best, but I should add that I speak only from +imagination and not from experience. The independent steering, the +impossibility of capsizing forward or sideways, the position of the +rider over his work, the absence of any little wheel with its mud +throwing and vibrating tendencies, combine to make a machine which +ought to be superior in almost every desirable quality to any +other; what it may be in practice I hope to hear in the +discussion.</p> + +<p>Of double tricycles, the Sociable has been tried by many, and is +practically a failure in so far as traveling quickly and easily is +concerned. The Tandem, though it presents so objectionable an +appearance, seems likely to become a favorite, for it surpasses any +single tricycle, and rivals the bicycle in speed. How it may +compare in comfort or in safety with the single machine, perhaps +those few who are well acquainted with them will say; at any rate, +in the case of the Humber, greater stability is given to the +steering, owing to the weight of the front rider.</p> + +<p>Time will not allow me to say more of these machines, or to +attack the subject of steam, electric, or magic tricycles, which I +had hoped to do. With steam and electricity we are well acquainted; +by magic tricycles, I mean those driven by a motor which, without +any expense, will drive one twenty miles an hour, up or down hill, +with perfect safety. Highway regulations, and certain reasons not +well understood, have at present prevented these contrivances from +making a revolution.</p> + +<p>There remains one machine which must be considered separately, +for it cannot be classed with any other. This is the Otto bicycle. +My opinion of this machine is so pronounced that I do not care to +state it fully. I shall merely give the reasons why I prefer it to +anything else, and in so doing I shall be taking the first step in +the discussion, in which it will be interesting to hear from riders +of other machines the reasons for their preference.</p> + +<p>In the first place, the evils of a third or little wheel, the +cause of trouble in all tricycles, are avoided. There is none of +the vibration which makes all other machines almost unbearable to +Ottoists, vibration which tricyclists have learnt to consider a +necessary accompaniment of cycling, but which has, no doubt, been +diminished by the use of the spring support of the front steering +Humber. It would be presumptuous in me to make any remarks on the +effect of this vibration on the human system; we shall all be +anxious to hear what our Chairman has to say on this point. By +having only two wheels, we have only two tracks, so that we can +travel at a fair speed along those places in the country called +roads, which consist of alternate lines of ruts and stones, where a +three-track machine could not be driven, and where, from the +quantity of loose limestone in the ruts, a little wheel of a +two-track tricycle would be likely to suffer. By having no little +wheel, we can ride in dirty weather without having the rest of our +machine pelted with mud, so that cleaning takes less time than it +does with anything else. As I have already remarked, the small +wheel is the culprit which makes the bicycle and tricycle drive so +heavily on a soft road. The ease with which the Otto can therefore +be run through the mud astonishes every one. Having no little +wheel, we can obtain the full advantage of the high 56 inch wheel, +which almost every one prefers. As I have ridden all combinations, +from a 50 inch geared up to 60 inch, to a 60 inch geared level, I +can speak from experience of the increased comfort to be derived +from these large wheels, though for speed only they do not compare +with the smaller and lighter wheels geared up. A further point +gained by the use of two wheels only is the fact that the whole +weight of machine and rider is on the driving-wheel, as it is also +on the steering-wheel, so that by no possibility can the wheels be +made to slip in the driving, or to fail in steering from want of +pressure upon them.</p> + +<p>The most important consequence, however, is the absence of any +fixed frame. In all machines, bicycles and tricycles, with the +usual fixed frame, a position is found for the saddle which is, on +the whole, most suitable. For some particular gradient it will be +perfect; on a steeper gradient the treadles will be further in +advance, but with a steeper gradient the rider should be more over +the front of the treadles. To get his weight further to the front, +he has to double up in the middle, and assume a position in which +he cannot possibly work to advantage. The swinging frame of the +Otto carries the treadles, of necessity, further back, so that the +Ottoist, when working at his hardest, is still upright, with his +hands in the line between his shoulders, and his feet and his arms +straight, so that he can hold himself down, and employ his strength +in a perfectly natural position. On going down a slope, the fixed +frame of a bicycle or tricycle leans forward, and places the rider +in such a position that extra weight is thrown on his arms and his +shoulders, whereas the swing frame of the Otto goes back, and the +rider of necessity assumes that position in which his arms are +relieved of all strain. In so far as the general position taken by +the automatic Otto frame is concerned, nearly the same effect can +be obtained by using the swing frame of the Devon tricycle, which +can be shifted and locked in any position which the rider wishes, +or by the sliding saddle, which can be slid backward or forward and +locked so as to place the rider in one of three positions. Though +the rider can by these devices assume nearly that position with +respect to the treadles which is most advantageous, he cannot +obtain that curious fore and aft oscillation made use of by the +Ottoist in climbing hills, which, as the model on the table shows, +enables him to get past the dead points without even moving, and +which, therefore, makes the Otto by far the best hill-climbing +machine there is, if account is taken of the high speeding with +which all Ottoists ride. This is a proposition which none who knows +the machine will question for one moment.</p> + +<p>The freedom of motion resulting from the swing of the frame of +the Otto gives a pleasurable sensation, which those who have only +experienced the constrained motion of a three-wheeler cannot even +understand.</p> + +<p>The very peculiar method of driving and steering, which seems so +puzzling to the novice, especially if he is a good rider of other +machines--for in that case he is far worse off than one who has +never ridden anything--give the rider, when he is familiar with +them, a control over the machine which is still surprising to me. +In the first place, the machine will run along straight, backward +or forward, so long as the handles are let alone. This automatic +straight running is a luxury, for until a deviation has to be made, +the steering handles need not be touched, and the rider may, if +sufficiently confident, travel with his arms folded or his hands in +his pockets. The rigid connection between the cranks and the wheels +does away with all the backlash, which is so unpleasant with chain +or toothed wheel gearing. There is no differential gear or clutch, +but the machine possesses the advantage of the clutch over the +differential gear when meeting with unequal resistance on a +straight course, for each wheel must travel at the same speed; but, +in turning a corner, instead of driving the inner wheel only, which +is done by the clutch or both wheels equally, which is the case +with differential gear, each wheel is driven, but the outer one +more than the inner. At high speeds, the steering of the Otto has +this advantage, that whereas, with a given action on a tricyle, the +same deviation will be effected in the same <i>space</i> at high as +at low speeds, the same action on the Otto will, at high speeds, +produce the same deviation in the same <i>time</i> as it does at +low speeds; and so instead of becoming more sensitive at high +speeds, as is the case with the tricyle, the steering of the Otto +remains the same. This is because the steering of the tricycle +depends on a kinematical, that of the Otto on a dynamical +principle.</p> + +<p>In another respect, no machine can approach the Otto; at almost +any speed the rider can, if there is reason, instantly dismount, by +which action he puts on the brakes, and the machine will save him +from falling, stopping with him almost instantly. As is well known, +we can move backward and forward, we can twist around and around in +our own width, or can ride over bricks with impunity.</p> + +<p>One objection to the machine is the difficulty of learning, +which is considerable, but which presents no danger. This +difficulty has been much exaggerated, for before the present +powerful brake was applied it did require considerable skill to +ride it down a steep hill. The way to do this must still be learnt, +but it is now comparatively easy. For going down steep hills, the +front steering tricycle is without a rival; I do not know what +other machine will do this better than the Otto. Lastly, the foot +straps, which would be a great advantage on any machine, if only +they were safe, are not--though none but riders will believe it--in +any way a source of danger on the Otto. Having ridden this machine +for close upon 10,000 miles, I can speak with more authority on +this point than can those who are not able to sit upon it for a +moment.</p> + +<p>The only disadvantage which the machine presents is the fact +that it is impossible to remove the feet from the pedals while +running, without dismounting; but though they must at all times +follow the pedals, the Ottoist is not, as is generally thought, +working when descending a hill.</p> + +<p>The enthusiastic terms in which every one who has mastered the +peculiarities of the Otto speaks of it would be considered as +evidence in its favor, if we were not all considered by other +cyclists to be in various stages of lunacy.</p> + +<hr> +<p><a name="5"></a></p> + +<h2>THE CANAL IRON WORKS, LONDON.</h2> + +<p>Some interest is awakened in engineering circles in London, just +now, by the approaching close of the old engineering works so well +known as the "Canal Ironworks," at the entrance to the Isle of +Dogs, London, E. This notable establishment stands second in +priority in London--that of Messrs. Maudslay, Sons & Field +being the oldest--for the manufacture of marine engines. It was +founded by the late Messrs. Seawards, above sixty years ago. Here +was originated Seaward's hoisting "sheers" with the traveling back +leg, a modern example of which, 100 feet high, in iron, stands on +the wharf. An interesting tool, also, is the large vertical boring +machine for largest size cylinders; Seaward spent £5,000 upon +this, and it is certainly an admirable tool. There is also the +large vertical slotting machine, with a stroke up to 5 feet 2 +inches, a wonderfully powerful and compact machine. The extensive +collection of screwing tackle is, perhaps, unsurpassed, and extends +up to 8 inches diameter. There is a peculiar erecting shop roof, +which will still repay examination.</p> + +<hr> +<p><a name="6"></a></p> + +<h2>MARINONI'S ROTARY PRINTING PRESS.</h2> + +<p>The greatest progress that has been made in recent years in the +art of printing is in the invention of the high speed press +provided with continuous paper.</p> + +<p>Three French constructors, Messrs. Marinoni, Alauzet, and +Derriey, have brought this kind of apparatus to such a degree of +perfection that the majority of foreign journals having a large +circulation buy their presses in France. We reproduce in Fig. 1 a +perspective view of the Marinoni press, and in Fig. 2 a diagram +showing the parts of the same. In order to give a complete +description of it, we cannot do better than to reproduce the very +interesting study that has been made of it by Mr. Monet, a civil +engineer.</p> + +<p class="ctr"><a href="images/4a.png"><img src= +"images/4a_th.jpg" alt= +"FIG. 1.--MARINONI'S ROTARY PRINTING PRESS."></a></p> + +<p class="ctr">FIG. 1.--MARINONI'S ROTARY PRINTING PRESS.</p> + +<p>The roller, J (Fig. 2), is placed in the machine in the state in +which it is received from the paper manufactory. The paper unwinds, +runs over the rollers, e and e', which serve only for tautening it, +and then passes between the two cylinders, A and B. The cylinder, +A, carries the form, and B carries the blanket, and the paper thus +receives its first impression. It afterward passes between the +cylinders, A' and B', and receives an impression on the other side, +the cylinder, A', carrying the form, and B' the blanket. Being now +printed on both sides, it passes between the cylinders, KK', which +cut it off and allow the sheet to slide between the cords of the +rollers. These latter lead the sheets over the rollers, g h, on +which they wind, one over the other, when the rollers, a a', are in +the position shown by unbroken lines in the cut.</p> + +<p>The part of the machine that holds the rollers, g h, and the +different cords that wind over them, is the <i>accumulator</i>, and +it is in this part of the press that the sheets accumulate, one +over the other, to any number desired.</p> + +<p>The size of the rollers, g h, and their distance apart are so +regulated that when the sheet reaches the accumulator, it falls +exactly on those that have preceded it. When the proper number of +sheets is in the accumulator (4 or 5 being the number most employed +for afterward facilitating the separation into packets on the +receiving table), the two small rollers, a a', advance over the +rack, N, and the sheets, instead of continuing to roll over into +the accumulator, fall on the rack and are deposited by it upon the +receiving table, O.</p> + +<p class="ctr"><a href="images/4b.png"><img src= +"images/4b_th.jpg" alt="FIG. 2.--MARINONI'S PRESS."> +</a></p> + +<p class="ctr">FIG. 2.--MARINONI'S PRESS.</p> + +<p>The rack having fallen twenty times, and deposited five sheets +each time, or one hundred in all, the table moves in such a way as +to prevent the sheets subsequently deposited from getting mixed +with them. When the rack has fallen twenty times, the table returns +to its initial position.</p> + +<p>The distributing rollers, D, come in contact with the inking +rollers, I, once during each revolution of the printing cylinders, +and are mounted on racking levers provided with regulating screws +that permit of easily regulating the amount of ink taken up. The +supports of the inking rollers are movable and can be made to +approach or recede from the distributing rollers, so as to still +further vary the amount of ink taken up by them.</p> + +<p>The distributing rollers supply the ink to a roller, E, of large +diameter, which, having a backward and forward motion, begins to +distribute the ink and to transmit it to a second roller, F, of the +same diameter. This latter then spreads it over a metallic +cylinder, G, which is of the same diameter as the printing +cylinders, and against which revolve three distributing rollers, H, +that have a backward and forward motion.</p> + +<p>Between the cylindrical inking table, G, and the type cylinder, +there are situated inking cylinders, T, of large diameter, that +constantly take up ink from the inking table and distribute it over +the types.</p> + +<p>The machine here described, when designed for printing large +sized journals, has cylinders whose circumference corresponds to +the size of paper for two widths of pages, and whose length is +sufficient to allow it to receive two forms. Each cylinder, then, +carries four forms, or eight in all, and prints two complete copies +at each revolution.</p> + +<p>The large sheet cut off by the cylinders, K K', contains, then, +two copies; and this sheet, on passing under the roller, f is again +cut in two by a disk which separates it in a direction +perpendicular to the cylinders.</p> + +<p>To this press there may be added a mechanical folder of Mr. +Marinoni's invention, capable of folding a journal five +times.--<i>Annales Industrielles</i>.</p> + +<hr> +<p><a name="7"></a></p> + +<h2>CHENOT'S ECONOMIC FILTER PRESS.</h2> + +<p>Mr. E. Chenot, who is occupied in the manufacture of wine from +dry grapes, has been led to devise a new style of filter, which by +reason of its mode of action and its construction, he calls the +"Economic Filter Press."</p> + +<p>The apparatus, which is shown in the accompanying cut, consists +of flat bags whose mouth may be at the top, as usual, or at the +side. Through this orifice there is introduced a flat piece of wood +or metal, which, like the bag, has an aperture through the center. +The whole is suspended from a distributing pipe that is fixed at +one end to the frame and is free at the other. This pipe is slotted +beneath, and the pieces of wood or metal contain, opposite the +slot, a number of small apertures that put the distributer in +communication with the interior of the bags. Between these latter +there are placed wire cloth frames which hold them in position and +facilitate the flow of the filtered liquid. The cut shows the +filter provided with a portion of its bags and frames. When all the +frames are in place they are locked by causing the movable plate to +move forward by means of two screws connected with an endless chain +and actuated by a hand wheel. The pressure of this plate closes up +the bags hermetically. Then, the feed cock being opened, the liquid +flows into all the bags, deposits therein what it holds in +suspension, and the clarified product flows to the inclined bottom +of the filter and from thence to the exterior.</p> + +<p class="ctr"><img src="images/4c.png" alt= +"CHENOT'S ECONOMIC FILTER PRESS."></p> + +<p class="ctr">CHENOT'S ECONOMIC FILTER PRESS.</p> + +<p>The apparatus may be supplied either through an upper reservoir, +a juice elevator, or a pump. The discharge is proportional to the +square root of the pressure. When the bags are full of residuum, +the feed cock is closed, the filter is unscrewed, and the bags and +frames are taken out. With fresh bags and the same frames, it is +possible to at once set the apparatus in operation again.</p> + +<p>Before the filter is taken apart, the residuum may be exhausted +by washing it either with water or steam, or by pressure. To effect +the operation by pressure, the pieces of wood or metal are removed, +the mouths are closed by making a fold in the top of the bags, and +the latter are then put back into the apparatus or into an ordinary +press and submitted to another squeezing.</p> + +<p>To render the maneuvering of it easier, the apparatus has been +given a horizontal position.--<i>Revue Industrielle</i>.</p> + +<hr> +<p>[American Engineer]</p> + +<p><a name="8"></a></p> + +<h2>STEEL CHAINS WITHOUT WELDING.</h2> + +<p>We take the following description, together with the +illustrations, of a method and machine for making steel chain +without welding, from our valued contemporary, <i>Le Genie +Civil</i>, of Paris:</p> + +<p>When we regard an ordinary oval-linked chain endwise, it +presents itself in the form of a metal cross, and it was this that +gave the cue to M. Oury, of the Government Arsenals, to construct +chain without welding. By a series of matrices and punches, etc., +he contrives, with small loss of metal, to model a chain out of +cross-shaped steel bar.</p> + +<p>Steel is the better material for such usage, from its +homogeneity, both as to composition and strength.</p> + +<p>Referring to the plate below, Figs. 1 to 10 explain the +successive steps from the bar to the finished chain.</p> + +<p>Fig. 1 shows in plan and section the steel bar, whose length may +be some 40 feet, and which would make a chain say 50 feet long. The +shape of the bar presents no difficulties in the way of +rolling.</p> + +<p>Figs. 2 and 3 give, in side elevations of the two faces and +sections, the first rough form of the links. These first begin to +take the exterior shape with the rounding of the angles.</p> + +<p>The operations following, represented by Figs. 4 and 5, is the +piercing of the center of the links, which can later be furnished +with a stay for such chains as require special strength. The point +now is to detach the links, which is accomplished by oblique +piercings, as shown in Fig. 6. In the operation represented by Fig. +7, the oval shape is imparted to the link, and the operation +finishes as shown in Fig. 8.</p> + +<p>Actually, the links are circular and separate. This separation +is retarded as much as possible, for it is plain that it is easier +to operate a rigid bar than a chain, above all when the operation +necessitates its being pushed forward.</p> + +<p>By means of a good system of heating, analogous to that employed +on the large parts entering into ship construction, it is hoped to +perform a major part of the operations, of which we have given but +an idea, at a single heat.</p> + +<p class="ctr"><a href="images/5a.png"><img src= +"images/5a_th.jpg" alt= +"MACHINE FOR MAKING CHAIN WITHOUT WELDING."></a></p> + +<p class="ctr">MACHINE FOR MAKING CHAIN WITHOUT WELDING.</p> + +<p>These operations require work on both faces alternately--this +presents no difficulties; but what appears to us most difficult to +realize is <i>continuous work</i>, the bar passing through several +machines which successively impress upon it the steps of progress +toward the finished chain. If the machines are end on to each other +in a direct line, there will necessarily be a fixed place for each +tool; the rough cut chain must accurately reach the point where +another tool is ready to continue the modeling. This appears to us +practically impossible, the more so as the elongation which the bar +takes at each stamp varies with its initial diameter.</p> + +<p>What is more admissible is that with one heat and in the same +machine an operation could be performed on the two faces +perpendicularly. The bar could then be taken from one furnace and +put in another immediately, to pass at once to another machine to +again undergo the operations following. The work could then be done +rapidly, submitting the bar to several heats.</p> + +<p>A few words on the tools as they exist.</p> + +<p>The most important principle to note, and on which the different +machines employed are designed, is this: The punches or matrices +acting on the chain at its different points of progress are put in +motion by spiral springs worked by means of tappets or cams +distributed over the circumference of a cylinder, having a rotary +movement imparted to it by pulleys and belts.</p> + +<p>The figures on our plate show with sufficient clearness the +working of one of these machines. It will be seen that the bar +traverses through and through the machine for stamping, and that it +can be disengaged for a reheating before passing to subsequent +operations.</p> + +<hr> +<p>The bog peat of Mexico is now being used on a considerable scale +as fuel for locomotives, stationary engines, smelting purposes, +smiths' fires, and househould use. The peat is mixed with a proper +proportion of bitumen, and is said not only to burn freely, and +without smoke in much quantity, but to give a higher dynamic +equivalent of heat than the same amount of wood.</p> + +<hr> +<p><a name="1"></a></p> + +<h2>THE BITTER SUBSTANCE OF HOPS.</h2> + +<p>[Footnote: <i>The Brewers' Guardian</i>, from the <i>Zeit. f. d. +gesammte Brauwesen</i>.]</p> + +<h3>By DR. H. BUNGENER.</h3> + +<p>Little that is definite is known of the substance or substances +to which the hop owes its bitterness. Lermer has succeeded, it is +true, in separating from hops a crystallized colorless substance, +insoluble in water, an alkaline solution of which has a marked +bitter flavor, and which easily changes on exposure to the air, +assuming a resinous form. According to Lermer, the formula of this +substance is C<sub>32</sub>H<sub>50</sub>O<sub>7</sub>; it +possesses the properties of a weak acid and forms a characteristic +copper salt, which is soluble in ether. This hop bitter is, +however, produced from the hop by a very roundabout process, by +treatment of the extract with alkalies; it is not therefore +regarded by many as present in this form in the hop, and they hold +that it is only produced by the action of the alkalies. On the +other hand, however, Etti, by a complicated extracting process, but +without using an alkali, succeeded in producing a bitter substance +from hops, which is, however, soluble in water.</p> + +<p>Several experiments convinced me that there really existed in +hops a crystallizable substance, insoluble in water, the alcoholic +and alkaline solution of which had a bitter flavor, in short, which +possessed all the properties of Lermer's hop bitter acid. Petroleum +ether is the best practical solvent in use for its isolation, as it +does not dissolve the majority of the remaining constituents of the +hop, especially the hop-resin, which they contain in considerable +quantity. Still, the extraction of hop-bitter acid from hops is a +troublesome and thankless job, the petroleum ether taking up +certain substances which add greatly to the difficulty of purifying +the crystals. On the other hand, we can readily and quickly attain +our object, if we employ for our original material fresh lupuline +from unsulphured hops.</p> + +<p>The following process has furnished me the best results:</p> + +<p>The lupuline is first freed from gross impurities (hop-seed +leaves, etc.), and then covered with petroleum ether boiling at a +low temperature (40° to 70°) in stoppered flasks. The +mixture is shaken up from time to time. After twenty-four hours, by +means of a Zullowsky filter immersed in the mass, and with the aid +of a suction-pump, the dark brown solution is drawn off; then fresh +ether is poured on to the lupuline, and it is allowed to stand for +another twenty-four hours. After this process has been three times +repeated, nearly everything the petroleum will dissolve has +probably been extracted. The solutions are put together, and the +petroleum ether distilled off <i>in vacuo</i> at a low temperature, +until there remains in the flask a dark brown sirup, which on +cooling solidifies into a crystalline mass. This is pulverized and +turned on to a filter composed of a large funnel, in which a +smaller funnel covered with muslin is inserted. With the aid of a +suction-pump, the greater portion of the thick, crude solution can +be filtered through. There remains on the filter a highly colored +crystalline "cake," which should be pulverized with a small +quantity of petroleum ether and again filtered. After this +operation has been repeated three or four times, we obtain an +almost colorless mass, consisting of hop-bitter acid, contaminated +by small quantities of a fatty substance, and a substance which I +could not isolate, and which I had at first great trouble in +separating from the hop-bitter acid.</p> + +<p>If we do not wish to utilize this crude substance at once, it +will be necessary to melt it in the water bath and pour it into a +bottle under close seal, where it will at once crystallize and +solidify. If it remains exposed to the atmosphere, it will soon +become sticky and turn partly into resin. Six kilos of lupuline, +which included a large proportion of sand, furnished 400 grammes of +crude hop-bitter acid. The first experiments in crystallization +with petroleum ether gave poor results; it is difficult to produce +the acid pure in large quantities by this process, as a small +quantity of the above substance obstinately clings to it, and it +readily assumes a non-crystallizable form. Our object is more +readily attained if we crystallize it once from alcohol, for which +purpose we dissolve it in a little lukewarm alcohol, then quickly +cool the solution; flakes of a fatty substance will be separated, +which are removed by filtration with the aid of a suction-pump. +Then we throw a few small crystals of the acid into the solution, +and after a short time crystallization commences. As soon as it +appears to be ended, the mother solution is removed with the aid of +a platinum cone, and the crystals washed with a little cold +alcohol. The alcoholic mother solution, which still contains the +chief part of the bitter acid, must be quickly evaporated, and the +residue consigned to a flask. The acid crystallized from the +alcohol is then recrystallized several times from petroleum-ether. +In order to quickly dissolve the bitter substance, it should be +carefully melted in a flask, and double its volume of ether +gradually added; on its cooling, we obtain beautiful prismatic +crystals, which attain a length of 1 cm., and become perfectly pure +after four or five crystallizations. The mother solutions must be +speedily evaporated if we still wish to obtain crystals; after a +time they will only furnish a resinous residue.</p> + +<p>The hop-bitter acid melts at 92° to 93°. It is easily +soluble in alcohol, ether, benzol, chloroform, sulphide of carbon, +and vinegar; to a lesser extent in cold petroleum ether, and not at +all in water.</p> + +<p>In the analysis I obtained figures which correspond best with +those calculated from the formula +C<sub>25</sub>H<sub>35</sub>O<sub>4</sub>.</p> + +<pre> + Obtained. + Calculated. ------------------------^----------------------- + -----^----- 2. Crystal. 3. Crystal. 5. Crystal. 6. Crystal. + p.c. p.c. p.c. p.c. p.c. p.c. p.c. + C 75.19 74.79 74.83 74.9 75.04 75.05 75.07 + H 8.77 8.97 8.90 8.85 8.87 8.83 8.80 + O 16.04 +</pre> + +<p>If we shake up the ether solution of bitter substance with an +aqueous solution of acetate of copper, the ether will assume a +green color, and gradually deposits a green crystalline powder, a +cupreous combination of the bitter acid. It is difficult to obtain +in a pure state, as the solutions are readily subject to slight +decomposition, accompanied by a small deposit of copper oxide. This +combination is readily soluble in alcohol, to a lesser extent in +ether, and is insoluble in water.</p> + +<p>In the course of analysis, I obtained the following figures:</p> + +<pre> + C 69.4 per cent. 69.3 per cent. + H 7.95 " 7.98 " + Cu 7.20 " 7.18 " +</pre> + +<p>If we suppose that the copper combines with two molecules of +hop-bitter acid, by the decomposition of one of its atoms, H, we +obtain the formula C<sub>50</sub>H<sub>68</sub>O<sub>8</sub>Cu. +This combination will contain 69.87 per cent. C, 7.91 per cent. H, +and 7.33 per cent. Cu. The figures obtained do not perfectly +coincide with those calculated; it is nevertheless probable that +the formula is correct, and the combined substance analyzed was not +perfectly true.</p> + +<p>I have already referred to the fact that solutions of hop-bitter +acid, if left standing too long, assume a yellow color, and on +evaporation leave only a yellow resinous residue. This, as its +reaction shows, evinces a complete analogy with the crystallized +acid. The dark-colored mother solution, from which the crystalline +cakes of bitter acid are obtained, contains a large proportion of +this resinous compound, which can be isolated by treatment with a +weak soda-lye; this substance, like the crystallized acid, is +soluble in alkalies, and can be precipitated from an alkaline +solution by an acid. Old hops furnish far less crystallizable acid +than new hops; from some samples I have been able to obtain only a +few crystals; the remainder had been transformed into the resinous +modification.</p> + +<p>If pure hop-bitter acid be pulverized and exposed to the +atmosphere, it soon turns yellow and the surface assumes a resinous +consistency. At the same time, a more pronounced odor of fatty +acids and aldehydes is apparent. Still more rapidly will this +oxidation occur if a thin layer of an alcoholic solution of the +acid is allowed to evaporate in the air. On the other hand, we can +allow hop-oil to stand for days without its odor being perceptibly +changed; it appears to me more than probable that the peculiar +smell of old hops is due far more to the oxidation of the bitter +substance than to the oxidation of oil.</p> + +<p>Hop-bitter acid appears to possess the character of an aldehyde +and of a weak acid; for the present I am not in a position to state +its constitution more clearly. Most of the oxidizing processes have +an energetic effect on it, forming also considerable quantities of +valerianic acid.</p> + +<p>The question as to whether the hop owes chiefly to this acid and +its resinous modifications the property of imparting a pronounced +bitter flavor to a solution, I must for the present leave +unanswered. The acid and its isomer are both insoluble in water; +they are, on the other hand, very readily dissolved in hop oil; +they also furnish a tolerably bitter solution, if boiled for a long +time in water, probably on their account of their gradual +decomposition. I will not for the present go further into the +subject, as I hope soon to be in a position to give more definite +information.</p> + +<hr> +<p><a name="17"></a></p> + +<h2>ST. PAUL'S VICARAGE, FOREST HILL, KENT.</h2> + +<p>This vicarage, for the Rev. Frank Jones, has recently been +completed from the designs of Mr. E.W. Mountford, A.R.I.B.A.; of 22 +Buckingham Street, Strand, W. C., and Mr. H. D. Appleton, +A.R.I.B.A., of the Wool Exchange, Coleman Street, E. C., who were +the joint architects. The builder was Mr. William Robinson, of +Lower Tooting, S. W. The walls are of yellow stock bricks, with red +brick arches, quoins, etc., the gables being hung with Kentish +tiles and the roofs covered with Broseley tiles. The internal +joinery is of pitch pine.</p> + +<p class="ctr"><a href="images/6a.png"><img src= +"images/6a_th.jpg" alt= +"ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM ROAD."></a></p> + +<p class="ctr">ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM +ROAD.</p> + +<p class="ctr"><a href="images/6b.png"><img src= +"images/6b_th.jpg" alt= +"ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM GARDEN."></a></p> + +<p class="ctr">ST. PAUL'S VICARAGE, FOREST HILL.--VIEW FROM +GARDEN.</p> + +<p>The illustrations are from drawings by Mr. J. Stonier.--<i>The +Architect</i>.</p> + +<hr> +<p><a name="9"></a></p> + +<h2>SOME ECONOMICAL PROCESSES CONNECTED WITH THE CLOTHWORKING +INDUSTRY.</h2> + +<p>[Footnote: Read before the Society of Arts, London, May, +1884.]</p> + +<h3>By Dr. WILLIAM RAMSAY, Professor of Chemistry at University +College, Bristol.</h3> + +<p>In this present age of scientific and technical activity, there +is one branch which has, I think, been the subject of an article in +the <i>Quarterly Journal of Science</i>. It is one which deserves +attention. It was there termed "The Investigation of Residual +Phenomena," and I can conceive no better title to express the idea. +The investigator who first explores an unknown region is content if +he can in some measure delineate its grand features--its rivers, +its mountain chains, its plains; if he be a geologist, he attempts +no more than broadly to observe its most important rock formations; +if a botanist, its more striking forms of vegetation. So with the +scientific investigator. The chemist or physicist who discovers a +new law seldom succeeds in doing more than testing its general +accuracy by experiments; it is reserved for his successors to note +the divergence between his broad and sweeping generalization and +particular instances which do not quite accord with it. So it was +with Boyle's law that the volume of a gas varies in inverse ratio +to the pressure to which it is exposed; so it is with the Darwinian +theory, inasmuch as deterioration and degeneration play a part +which was, perhaps, at first overlooked; and similar instances may +be found in almost all pure sciences.</p> + +<p>I conceive that the parallel from the technical point of view is +a double one. For just as every technical process cannot be +considered to be beyond improvement, there is always scope for +technical investigation; but the true residual phenomena of which I +would speak to-night are waste products. There is, I imagine, no +manufacture in which every substance produced meets with a market. +Some products are always allowed to run to waste, yet it is evident +that every effort consistent with economy should be made to prevent +such waste; and it has been frequently found that an attempt in +this direction, though at first unsuccessful, has finally been +worked into such a form as to remunerate the manufacturer.</p> + +<p>It is my purpose to-night to bring under your notice methods by +which saving can be effected in the cloth industry. I am aware that +these methods have not much claim to novelty; but I also know that +there are, unfortunately, few works where they are practiced.</p> + +<p>The first of these relates to the saving and utilization of the +soap used in wool scouring and milling. It is, perhaps, hardly +necessary to explain that woolen goods are scoured by being run +between rollers, after passing through a bath of soap, and this is +continued for several hours, the cloth being repeatedly moistened +with the lye, and repeatedly wrung out by the rollers. The process +is analogous to ordinary washing; the soap dissolves the greasy +film adhering to the fibers, and the "dirt" mechanically retained +is thus loosened, and washed away. Now, in order to dissolve this +greasy matter, a considerable amount of soap must be employed; and +in the course of purification of the fabric, not merely what may be +characterized as "dirt" is removed, but also short fibers, and +various dye-stuffs with which the fabric has been dyed, many of +which are partially soluble in alkaline water; moreover, it +invariably happens that some dye does not combine with the fiber +and mordant, thus becoming fixed, but merely incrusts the fiber; +hence this portion is washed off when the retaining film of grease +is removed from the fiber. The suds, therefore, after fulfilling +this purpose, are no longer a pure solution of soap, but contain +many foreign matters; and the problem is so to treat these suds as +to recover the fat in some condition available for re-conversion +into soap.</p> + +<p>For this purpose wooden runnels are placed beneath the rollers, +through which the cloth passes in the scouring machine, so as to +collect the suds after they have been spent. These runnels lead to +a wooden pipe or runnel, which receives the spent suds from all the +scouring machines, and the whole of the waste, instead of being let +off into the stream, polluting it, delivers into a tank or trough, +which may also be constructed of wood, but, as it has to withstand +the action of acid, is better lined with lead. This tank is +necessarily proportioned in size to the number of scouring machines +and the quantity of spent suds to be treated. When a sufficient +quantity has collected, oil of vitriol, diluted with twice its bulk +of water, is added, one workman pouring it in gradually while +another stirs the contents of the tank vigorously. At short +intervals, the liquid is tested by means of litmus paper, and when +it shows a faint acid reaction, by turning the blue paper red, the +addition of acid is stopped. The acid has then combined with the +alkali of the soap, while the fatty acids formerly in combination +with the alkali are liberated, and float to the surface of the +liquid, carrying with them the impurities in the shape of short +fibers and dye stuffs; the sand and heavier impurity, should any be +present, sinks to the bottom.</p> + +<p>After standing for some hours, the separation is complete. In +order to separate the two layers, the tank is provided with an exit +in the side, near the bottom, closed by a sluice or valve. This +valve is opened, and the watery portion is allowed to escape into a +sand filter bed.</p> + +<p>The filter serves to retain any solid impurities which may still +remain suspended in the water; but it will be found that the +escaping water is nearly pure.</p> + +<p>The dark brown fatty acid is mixed with a large amount of +impurity, such as short wool fibers, burrs, sand, and dye stuffs +washed from the wool. To remove water more completely, the +semi-fluid mass is pumped from the tank, and delivered into +hair-cloth filters; the liquid which drains from these bags finds +its ways to the sand filters joining the drainage which formerly +passed out from the tank through the sluice. After being turned +over in the filter several times, the residue is transferred to +canvas sacks. These sacks are placed in a filter press, where they +are exposed to pressure while heated to a temperature sufficient to +melt the fat. The solid impurities remain in the bags, while the +fatty acids escape, and are received in a barrel or tank for the +purpose. The fatty acids, when cold, are of a deep brown color, and +of the consistency of butter. The residue is kept, and the method +of treating it for the recovery of indigo will afterward be +described.</p> + +<p>The fatty acids are now ready for conversion into soap. It may +here be remarked that, on distillation, they yield a nearly white +fatty mass, which, when treated with soda-lye, is capable of +yielding a perfectly white soap. But, for the clothworker's +purpose, this purification is unnecessary.</p> + +<p>The conversion into soap is a very simple matter. As the fats +are acids--a mixture of palmitic, oleic, and stearic acids--and not +the glycerine salts of these acids, like ordinary fats, soap is +made by causing them directly to unite with caustic soda. The fats +are melted in a copper, by means of a steam-jacket, or coil of +steam-pipe in the copper, and the soda-lye is run in until complete +union has taken place. The exact point of neutralization can easily +be found by taking out a small sample after stirring, and +dissolving it in some methylated spirits. A few drops of alcoholic +tincture of phenol-phthalein are then added, and as soon as a faint +red color appears, addition of soda is stopped. This shows that the +fatty acids have been over-saturated. Addition of a little more fat +renders them perfectly neutral, and the soap is then ladled out +into wooden moulds, lined with loose sheets of zinc.</p> + +<p>The resulting soap is of a brown color, but is perfectly adapted +for the purpose of wool-scouring. It should here be mentioned that, +in practice, the soap is always made somewhat alkaline; in point of +fact, it contains about 2 per cent. of free alkali. This is found +to assist in scouring; I presume that the free alkali forms a soap +with the oil added to the wool during spinning, and if no free +alkali be present, this oil would not be so thoroughly removed.</p> + +<p>It will be noticed that in this simple method of soap-making, +there is no salting out to separate the true soap from the watery +solution of glycerine, for no glycerine is present. The apparatus +may be of the simplest nature, and on any required scale, +proportionate to the size of the mill. It is a process which +requires no specially skilled labor; in any works some hand may be +told off to conduct the process as occasion requires; and as a very +large proportion of the fatty matter is recovered, the soap-bill is +reduced to a very small fraction of the amount which would be paid +were recovery not practiced. And lastly, the streams are not +polluted; the only waste is a little sulphate of soda, which can +hardly be regarded as a nuisance, inasmuch as it is a not +unfrequent constituent of many natural waters.</p> + +<p>Let us now return to the solid matter from which the fatty acids +have been removed by pressure. This brown, earthly-looking cake +consists of vegetable impurity washed off from the cloth, of short +fibers, and of various dye stuffs. It is divided into two lots: +That which contains indigo, and that which contains none, or which +contains too small a quantity for profitable extraction. And it may +here be remarked, that it is advisable to collect the suds from +cloth dyed with indigo separate from that to dye which no indigo +has been employed. The residue from indigo-dyed cloth has always a +more or less blue shade, and if much indigo is present, the +well-known copper-color is evident. Of course, the amount of indigo +must greatly vary, but it may rise to 8 or 10 per cent. of the +total weight of the refuse.</p> + +<p>To recover the indigo from this refuse, the somewhat hard cakes +are broken up, placed in a tank, and allowed to steep in water. +When quite disintegrated, they are transferred to another tank--a +barrel may be used for small quantities--and thus this refuse is +exposed to the reducing action of copperas and lime. The indigo is +converted into indigo-white, and is rendered soluble, and it +oxidizes on the surface, forming a layer of blue froth on the top +of the liquid, while the remainder of the impurities sinks. This +process of reduction may last for twenty-four hours, and is helped +by frequent stirring.</p> + +<p>The indigo scum is preserved, and placed in filter cloths, where +it is thoroughly washed with water two or three times. The residue +which has sunk to the bottom is removed, dried, and forms a +valuable manure, owing to the amount of the nitrogen which it +contains. Its value may be increased by addition of weak vitriol, +which exercises a decomposing action on the nitrogenous matter, +forming with it sulphate of ammonia. The original residue from the +filter-press, if it does not contain indigo, may be at once put to +similar use.</p> + +<p>In large works, which dye their own goods, it is well known that +the "fermentation vat" is in general use for indigo-dyeing. But +this vat requires constant superintendence, and must be kept in +continual action; besides, it is successful only on a comparatively +large scale. And, moreover, it requires skilled labor. Small works, +or works in which dyeing is only occasionally practiced, find it +more convenient to use Schützenberger and Lalande's process. +Although this process is well known, a short description of it may +not here be out of place.</p> + +<p>The process depends on the reduction of indigo to indigo-white, +or soluble indigo, by means of hyposulphite, or, as it is generally +termed to avoid confusion with antichlore, rightly named +thiosulphate of soda, hydrosulphite of soda. The formula of this +substance is NaHSO<sub>2</sub>, as distinguished from what is +commonly known as hyposulphite of soda, +Na<sub>2</sub>S<sub>2</sub>O<sub>3</sub>. It is produced by the +action of zinc-dust on the acid sulphite of soda. The zinc may be +supposed to remove oxygen from the acid sulphite, +NaHSO<sub>3</sub>, giving hyposulphite, NaHS0<sub>2</sub>. The +reduction of the acid sulphite is best performed in a cask, which +can be closed at the top, so as to avoid entrance of air. The acid +sulphite of soda, at a strength of 50 or 60 Twaddell (specific +gravity 1.26 to 1.3), is placed in the cask, and zinc-dust is +added, with frequent stirring. The liquid is then mixed with milk +of lime, and after again thoroughly stirring, the liquid is allowed +to settle, and the clear is decanted into the dyeing-copper. The +indigo, in the frothy state in which it is skimmed from the +purifying barrels or tanks, is then added, with sufficient lime to +dissolve it when it has been reduced. It is heated gently by a +steam coil, to about 90° Fahr., and the goods are dyed in it. +The colors obtained by means of this indigo are light in shade, and +the goods must be dipped several times if dark shades are required. +But it is found better in practice not to attempt to dye dark +shades by this process; the ordinary indigo-vat is better adapted +for such work. The object of not wasting indigo is sufficiently +attained by employing it for the purpose to which it is best +adapted. Of course the recovered indigo may be used in the ordinary +manner. I merely mention the most convenient way of disposing of it +in works where only a small quantity is recovered, and which do not +practice dyeing on an extensive scale.</p> + +<p>I have now to ask you to turn to a different subject, namely, +the scouring of wool, not by the usual agent, water, but by a +liquid, bisulphide of carbon, made by the action of sulphur vapor +on red hot coke or charcoal.</p> + +<p>This, again, is not wholly a new process, for various attempts +have been made to dissolve out the yolk, or <i>suint</i>, or greasy +matter from unwashed wool, as it comes from the back of the sheep. +Fusel oil has been patented for this purpose. Carbon disulphide has +also been patented, but, as will afterward be shown, the old method +of removing it from the wool injured the color and quality of the +fiber, so as to make the application of this scouring agent a +failure.</p> + +<p>Wool in its unwashed state contains a considerable proportion of +what is termed <i>suint</i>. This consists of the fatty matter +exuded as perspiration from the sheep, along with, or in some form +of combination with, potash derived from the grass on which the +sheep feed. <i>Suint</i> was first investigated by Vauquelin. He +obtained it by evaporating, after filtration, the water in which +raw fleeces had been washed. The residue is of a brown color, and +has a saline, bitter taste. On addition of an acid to its solution +in water, it coagulates, and a fatty matter rises to the surface. +It is, in fact, a potash soap, to a great extent containing +carbonate and acetate of potash, along with chloride of potassium +and lime, probably in combination also with fatty acids. It is +usually mixed with sand and carbonate of lime.</p> + +<p>In 1828, M. Chevreul, who is still alive in Paris, although +nearly a century old, published an analysis of merino wool. It +consisted of:</p> + +<pre> + Per cent. + Pure wool 31.23 + Soluble _suint_ 32.74 + Insoluble 8.57 + Earthy matter 27.46 + ------ + 100.00 +</pre> + +<p>It is easily seen that <i>suint</i> forms a very important +constituent of raw wool. Its proportion varies, of course, +according to the nature of the pasture on which the sheep are fed, +the climate, etc. Wool from Buenos Ayres, for example, contains +much less than that analyzed by M. Chevreul; its amount is only 12 +per cent. of the weight of the raw wool.</p> + +<p>This <i>suint</i> contains always about 52 per cent. of residue +when ignited. The composition of this residue is:</p> + +<pre> + Per cent. + Carbonate of potash 86.78 + Chloride of potassium 6.18 + Sulphate of potash 2.83 + Silica, alumina, etc. 4.21 + ------ + 100.00 +</pre> + +<p>In 1859, MM. Maumene and Rogelet patented the use of the water +in which wool has been washed as a source of potash, and at present +the extraction of potash from <i>suint</i> is practiced in France +on a large scale. The wool is washed in a systematic manner, in +casks, with cold water, which runs out of the last cask with +specific gravity 1.1. These washings are evaporated to dryness, and +the residue is calcined in iron retorts, the gas evolved being used +for illuminating purposes. The remaining cinder, consisting of a +mixture of charcoal and carbonate of potash, is treated with water, +whereby the latter is dissolved out. The residue left on +evaporation of this water consists largely--almost entirely--of +white carbonate of potash. At present there are works at Rheims, +Elboeuf, Fourmier, and Vervier, which yield about 1,000 tons of +carbonate of potash annually. Now, only 15,000 tons are made per +annum by Leblanc's process. In 1868, 62,000 tons of wool were +imported into Britain from Australia alone, and from this 7,000 to +8,000 tons of carbonate of potash might have been recovered, the +value of which is £260,000. Yet it was all wasted! And this +estimate does not include the fats of the <i>suint</i>, which are +worth an even greater sum.</p> + +<p>Now, it is evident that there is here a profitable source of +economy. So far as I am aware, no work in this country saves its +washings. The water all goes to pollute the nearest river.</p> + +<p>The use of carbon disulphide has again been introduced, and it +is to be hoped with better success, for methods have been devised +whereby the wool is not injured by it, but is even rendered better +than when scoured by the old process of washing with carbonate of +soda and water, or by soap. The process is due to Mr. Thomas J. +Mullings. Briefly described, it consists in exposing the wool, +placed in a hydro-extractor, to the action of bisulphide of carbon; +the machine is then made to revolve, and the excess of solvent is +expelled, carrying with it the fatty matters; the solvent finds its +way into a tank, from which it flows into a still, heated with +steam; the carbon disulphide, which boils at a very low +temperature, distills over, and is again ready for use, while the +residue in the still consists of <i>suint</i> washed from the wool. +To remove the last trace of carbon disulphide from the wool in the +hydro-extractor, cold water is admitted, and when the wool is +soaked, the machine again revolves. On expulsion of the water, the +wool is ready for washing in the ordinary machines, but with cold +water only instead of hot soapsuds.</p> + +<p>The distinguishing features of Mr. Mullings' process are, method +by which loss of carbon disulphide is avoided, and the extraction +of that solvent by means of cold water. The apparatus consists of a +hydro-extractor or centrifugal machine of special construction, +fitted with a bell-shaped cover, which can be lifted into and out +of position by means of a weighted lever. The rim of this cover +fits into an annular cup filled with water, which surrounds the top +of the machine, forming an effective seal or joint. Upon the +spindle of this machine is suspended, as in ordinary forms of the +hydro-extractor, a perforated basket, and in this basket is placed +the wool to be treated. The cover being closed, the carbon +disulphide is admitted, and passing through the wool, the greasy +matter is dissolved, and along with the solvent enters a reservoir. +The machine is now set in motion, and the bulk of the solvent is +drawn off. Cold water is then admitted, and the machine being again +caused to rotate, the whole of the bisulphide is expelled. It is a +curious fact that, although wool soaks remarkably easily with +carbon disulphide, and at once becomes wet, cold water expels and +replaces almost all that liquid. This operation takes about twenty +minutes, and at one operation about 1½ cwt. of raw wool may +be treated. The wool is then washed in suitable washing machines of +the ordinary type, but with cold water, no soap or alkali being +employed. The bisulphide of carbon, mixed with water, flows into a +reservoir, provided with diaphragms to prevent splashing, and +consequent loss by evaporation. From its gravity it sinks, forming +a layer below the water; it is then separated and recovered by +distillation, and may be used in subsequent operations.</p> + +<p>The point in which this process differs from the old and +unsuccessful ones formerly tried, is in the expulsion of the carbon +disulphide. It was imagined that it was necessary to expel it by +means of heat or steam. Now, when wool moist with bisulphide is +heated, it invariably turns yellow. No heat must, therefore, be +employed. As already remarked, the solvent is expelled with cold +water.</p> + +<p>The residue, after distillation of the carbon disulphide, is a +grayish colored, very viscous oily matter, still retaining a little +bisulphide, as may be perceived from the smell. It has not the +composition of ordinary <i>suint</i>, inasmuch as it contains no +carbonate of potash, and indeed little mineral matter of any kind. +A sample which I analyzed lost in drying 36.2 per cent., the loss +consisting of water and carbon disulphide. It gave a residue on +ignition amounting only to 1.6 per cent. of the original fatty +matter, or 2.5 per cent. of the dried fat. The oil appears, from +some experiments which I made, to be a mixture of a glycerine salt +and a cholesterine salt of fatty acids. It distills without much +decomposition, giving a brown-yellow oil, which fluoresces +strongly, and has a somewhat pungent smell. The molecular weight +was determined by saponification with alcoholic potash, and +subsequent titration of the excess of potash employed. This was +found to equal 546.3. This would correspond to a mixture of 18.7 +parts of stearate, palmitate, and oleate of glycerine, with 81.3 +parts of the same acids combined with cholesteryl. But this is +largely conjecture. The boiling point of the oil is high, much +above the range of a mercurial thermometer, so that it is difficult +to gain an insight into its composition.</p> + +<p>An objection which has been raised to this process is that the +use of such an easily inflammable substance as bisulphide of carbon +is attended by great risk of fire. Were the bisulphide to be +exposed to free air, there might be force in this objection; but +there is no reason why it should ever be removed from under a layer +of water. The apparatus, to make all safe, should not be under the +same roof as the mill; and no open fire need be used in the +building set apart for it. It is easy to rotate the centrifugal +machine by a belt from the mill, but better by a small engine +attached, the power for which can be conducted by a small +steam-pipe, and the distillation of the bisulphide can also be +conducted without danger by the use of steam, as its boiling point +is a very low one. The question may be naturally asked, "How do the +wool and fabric made from the wool scoured by this process, compare +with that scoured in the usual way?" To answer this question I may +refer to a test made by Messrs. Isaac Holden & Co., at their +works at Roubaix. A sample of wool was divided into two portions, +one of which was scoured by the usual method, and the other by the +turbine or Mullings' process. Skilled workers then span each sample +to as fine a thread as possible. Now the thinness to which a wool +can be spun is evidence of its power of cohesion--in other words, +its strength. The weight of 1,000 meters of the wool cleaned by the +new process bore to that scoured by the old process the proportion +of 1,015 to 1,085, showing that a considerably finer thread had +been produced. And in total quantity, 67.53 kilos. of the former +corresponded to 71.77 kilos. of the latter, showing a +proportionately less waste. Such fine yarn had never before been +obtained from similar wool. The yarn of the soap-washed wool could +not be spun, for it could not withstand the strain; whereas, that +scoured by the new process gave an admirable thread.</p> + +<p>Another test to which it was subjected may be cited. It is the +custom in France, before the wool is scoured, to put it through a +sorting process, by which all the short lengths are weeded out. On +a quantity exceeding 11,000 kilogrammes, half of which was scoured +by the turbine process, and half by the ordinary process, the +former in scouring lost in weight 2 per cent. less than the latter, +although the short length extracted from the moiety thus treated +weighed only 10 kilogrammes, while that taken from the other +weighed over 150 kilogrammes. This saving, even with the unequal +treatment, amounted in value to from 30 to 40 centimes per +kilogramme.</p> + +<p>In order that the importance of this application may be +realized, I shall conclude with some figures:</p> + +<p>The raw wool imported into England, in the year 1882, amounted +to 1,487,169 bales, its total value being about £22,000,000. +The cost of washing this wool by the old process, with carbonate of +soda, amounts to about ½d. per lb. of the raw material. The +cost for the total quantity of wool imported is at least +£1,214,000. But it is customary to wash wool with soap, +especially for the combing trade, and the cost is then about 1d. +per lb. The cost of scouring by the new process is about £1 +5s. per ton, or 0.13d. per lb. Taking the least favorable +comparison, were all the imported wool (home-grown wool is here +left out of the calculation, for want of sufficient returns) +cleansed by the turbine process, the actual saving would be +£1,214,500 <i>minus</i> £315,700, or nearly +£900,000 per annum.</p> + +<p>It is thus seen that there is room for a very important economy +in the treatment of wool. I have endeavored to show how economy may +be practiced in scouring by the old process with soap, and how one +dye stuff may be profitably recovered. It is to be hoped that means +of extracting other dyes from the residue may soon follow. Unless +the process were too costly to repay the trouble of extraction, it +would be well worth practicing; for it would not merely be a +solution of the problem of how to avoid waste, but would at the +same time prevent the pollution of our streams, now, unfortunately, +only too rarely pellucid; and were the last process to have as +successful a future as I hope it may have, a very important saving +of expense would result, and a large quantity of valuable fatty +matter would no longer be thrown away.</p> + +<hr> +<p><a name="18"></a></p> + +<p class="ctr"><img src="images/7a.png" alt= +"SUGGESTIONS IN DECORATIVE ART.--DESIGNS FOR IRON GATES."></p> + +<p class="ctr">SUGGESTIONS IN DECORATIVE ART.--DESIGNS FOR IRON +GATES.</p> + +<hr> +<p><a name="20"></a></p> + +<h2>COAL AND ITS USES.</h2> + +<p>[Footnote: From a paper lately read before the Association of +Foremen Engineers.]</p> + +<h3>By JAMES PYKE.</h3> + +<p>The records from which geologists draw their information can +scarcely be compared to written or printed histories. There are, +however, nations of whom no written account exists, who perhaps +never had any written history, but about whom we are still able to +gather from other sources a vast amount of information. Their +houses, their monuments, their weapons, and their tools have +survived, and these tell us the kind of life, the state of +civilization, and the skill of the men to whom they belonged; from +the contents of their tombs we learn what manner of men they were +physically; sometimes a sudden change in the appointments and +belongings of the folk indicates that tribes which had for a long +time inhabited a district were driven out and replaced by a new +race. Thus, then, from waifs and strays we can piece together a +fairly connected account of the events of a period long antecedent +to any written history.</p> + +<p>The investigations of Dr. Schliemann on the supposed site of the +city of Troy furnish a good example of this method of research. He +found lying, one on the top of another, traces of the existence of +five successive communities of men, differing in customs and social +development, and was able to establish the fact that some of the +cities had been destroyed by fire, and that later on other towns +had grown up over the buried remains of the earlier settlements. +The lowest layers were, of course, the oldest, and the position of +each layer in the pile gives its date, not in years, but with +regard to the layers above and below it.</p> + +<p>Now, from time immemorial nature has been at work building up +monuments and providing tombs which tell us what were the events +going on, and what kind of inhabitants the earth had long before +man made his appearance on its surface. The monuments are the rocks +which compose the ground under our feet, and these, like many +ancient monuments of human construction, are the tombs of the +creatures that lived while they were being built.</p> + +<p>Many facts testify that the earth's crust did not come into +existence exactly as we find it now, but that its rocks have been +built up by the slow action of natural agencies. These rocks +constantly inclose the remains of plants and animals, and as it is +evident that neither plant nor animal could have lived in the heart +of a solid rock, this fact shows that the rock must in some way +have gathered round the remains that are now found in it. Again, +many of these remains, or fossils, belonged to animals that lived +in water, the larger part, indeed, to marine creatures. This +indicates that the rock was formed beneath the sea, and when we +examine the way in which the constituents of the rock are arranged, +we frequently find it to correspond exactly with the manner in +which the sand and mud that rivers sweep down into the sea or lakes +are spread out over the bottom of the water. In a pile of rocks +formed in this way it is clear that the lowest is the oldest of +all, and that any one stratum lying above is younger than the one +beneath it. Further, the occurrence of rocks inland containing +marine fossils far above the sea level shows that the sea and land +have changed places. When, again, we find that the fossils of one +group of rocks differ entirely from those of a group lying above +them, we learn that one race of creatures died out and was +supplanted by a new assemblage of animal forms.</p> + +<p>These general remarks will, I trust, give some notion of the +evidence which is available for reconstructing the history of those +remote periods with which geology deals, and of the kind of +reasoning which the geologist employs for interpreting the records +that are submitted to him.</p> + +<p>We will now briefly examine, by aid of these methods, the group +of rocks in which coal occurs in Great Britain, and see how far we +can read the story they have to tell.</p> + +<p>The group with which we have to deal is called the carboniferous +or coal bearing system, and it includes four classes of rocks, +viz.: 1, sandstone; 2, shale or bind; 3, limestone; 4, coal and +underclay.</p> + +<p>We will take the sandstones and shales first. They are grains of +sand known to mineralogists as quartz, and consisting of a +substance called silica by chemists. The grains of sand are bound +together by a cement which in some few cases is identical in +composition with themselves, and consists of pure silica, but +usually is a mixture of sandy, clayey, and other substances. The +shales are made up very largely of clay, mixed, however, usually +with sand and other substances, forming a conglomerate. Both +sandstones and shales are divided into layers or beds, and are said +to be stratified. It is this stratified or bedded structure that +gives us the first clew to the way in which these rocks were +formed. Rivers are constantly carrying down sand and mud into the +sea or lakes, and when their flow is slackened on entering the +still water the materials they bring down with them sink and are +spread out in layers over the bottom. The structure of the +sandstones and shales shows that they were formed in this way; they +often inclose the remains of plants that have been carried down +from land, and occasionally of animals that lived in the water +where they were deposited.</p> + +<p>The next we have to consider is limestone, which is mainly made +up of a substance known to chemists as calcium carbonate, or +carbonate of lime.</p> + +<p>In some districts, especially in volcanic countries, springs +occur very highly charged with carbonate of lime. The warm springs +of Matlock are a case in point; they are probably the last vestige +of volcanic action which was in operation in that neighborhood +during carboniferous times. Limestone is chiefly formed by the +agency of small marine creatures of low organization. By the aid of +these animals the carbonate of lime is brought back to a solid +form; at their death their hard parts fall to the bottom and +accumulate in a mass of pure limestone, which afterward becomes +solidified into limestone rock.</p> + +<p>The information that limestone gives us is this:</p> + +<p>When we find, as is often the case, a mass of limestone hundreds +of feet thick, and composed of little else but carbonate of lime, +we know that the spot where it occurs was, at the time it was +formed, far out at sea, covered by the clear water of mid ocean; +and when we find that this limestone grows in certain directions +earthy and impure, and that layers of shale and sandstone, thin at +first, but gradually thickening out in a wedge-shape form, come in +between its beds, we know that in those directions we are traveling +toward the shore lines of that sea whence the water was receiving +from time to time supplies of muddy and sandy sediment.</p> + +<p>The next class of rocks are the clays that are found beneath +every bed of coal, and which are known as <i>underclays</i>, or +<i>warrant</i>, or <i>spavins</i>. They vary very much in mineral +composition. Sometimes they are soft clay; sometimes clay mixed +with a certain portion of sand; and sometimes they contain such a +large proportion of silicious matters that they become hard, flinty +rock, which many of you know under the name of <i>gannister</i>. +But all underclays agree in two points: they are all unstratified. +They differ totally from the shales and sandstones in this respect, +and instead of splitting up readily into thin flakes, they break up +into irregular lumpy masses. And they all contain a very peculiar +vegetable fossil called <i>Stigmaria</i>.</p> + +<p>This strange fossil was for a long time a sore puzzle to fossil +botanists, and after much discussion the question was fairly solved +by Mr. Binney by the discovery of a tree embedded in the coal +measures, and standing erect just as it grew, with its roots spread +out into the stratum on which it stood. These roots were Stigmaria, +and the stuff into which they penetrated was an underclay. Sir +Charles Lyell mentions an individual sigillaria 72 feet in length +found at Newcastle, and a specimen taken from the Jarrow coal mine +was more than 40 feet in length and 13 feet in diameter near the +base. It is not often these trees are found erect, because the +action of water, combined with natural decay, has generally thrown +them down. They are, however, found in very large numbers in the +roof of the coal, evidently having been tossed over, and lying +there flat and squeezed thin by the pressure of the measures that +lie above them.</p> + +<p>Lastly, we come to coal itself--a rock which constitutes a small +portion of the whole bulk of the carboniferous deposits, but which +may be fairly looked upon as the most important member of that +group, both on account of its intrinsic value and also from the +interest that attaches to its history. That coal is little else but +mineralized vegetable matter is a point on which there has for a +long time been but small doubt. The more minute investigations of +recent years have not only placed this completely beyond question, +but have also enabled us to say what the plants were which +contributed to the formation of coal, and in some cases even to +decide what portions of those plants enter into its composition. It +is a thing so universally admitted on all hands, that I shall take +it for granted you are all perfectly convinced that coal has been +nothing in the world but a great mass of vegetable matter. The only +question is: How were these great masses of vegetable matter +brought together? And you must realize that they were very large +masses indeed. Just to take one instance. The Yorkshire and +Derbyshire coal field is somewhere about 700 to 800 square miles in +area, and Lancashire about 200. Well, in both these coal fields you +have a great number of beds of coal that spread over the whole of +them with tolerable regularity and thickness, and very often with +scarcely any break whatever. And this is only a very small portion +of what must have been the original sheet of coal, so that you see +we have to account for a mass of vegetable matter perfectly free +from any admixture of sand, mud, or dirt, and laid down with +tolerably uniform thickness over many hundreds of square miles.</p> + +<p>At one time it was supposed that coal was formed out of dead +trees and plants which were swept down by rivers into the sea, just +in the same way as shales and sandstones were formed out of mud and +sand so swept down. The fatal objection to this theory, however, is +that rivers would not bring down dead wood alone, but they would +bring down sand and mud, and other matters, and that in the bottom +of the sea the dead wood would be mixed with these matters, and +instead of getting a perfectly unmixed mass of vegetable matter, we +should get a mixture of dead plants, sand, mud, and other things, +which would give rise to something like coal, but something very +different, as any one who tries to burn such coal will soon find +out, from really good, pure house coal. So that this theory, which +is generally known as the "drift" theory, was totally inadequate to +account for the facts as we know them.</p> + +<p>The other theory was that coal was formed out of plants and +trees that grew on the spot where we now find coal itself. On this +supposition it is easy to account for the absence of foreign +admixtures of sand, mud, and clay in the coal; and we can also +understand very much better than by the aid of the drift theory how +the coal had accumulated with such wonderful uniformity of +thickness over such very large areas. This theory was for some time +but poorly received; but after the discovery of Sir William Logan, +that every bed of coal had a bed of underclay beneath, and the +discovery of Mr. Binney, that these underclays were true soils on +which plants had undoubtedly grown, there was no doubt whatever +that this was the real and true explanation of the matter.</p> + +<p>I dare say many of you have had occasion to walk across peat +bogs. The peat bog is a great mass of vegetable matter, which is +every year growing thicker and thicker; and underneath it there is +almost always a bed of thin clay, in look very much like the +underclays, and this thin clay is penetrated by the rootlets of the +moss forming the peat, exactly the same way as the underclays of +the coal measures are penetrated by the stigmaria and its rootlets. +But you must not suppose that the plants out of which coal was +formed were exactly the same low type of moss which forms our +present peat bogs. However, it is pretty certain that they were for +the most part of a loose, succulent texture, and that they grew +very rapidly indeed.</p> + +<p>You will have noticed that there is one step more wanted to make +good this theory of the growth of coal on the spot where we now +find it. The coal is found, as already described, interbedded with +shales and sandstones. These shales and sandstones, as shown, were +formed beneath the water of the sea, and as long as they remained +there of course no plants could grow upon them. The question is, +How was the land surface formed for the growth of plants? It must +have been formed in some way or other by the sea bottom having been +raised above the level of the water. Now, we have distinct proof in +many cases that elevation of the sea bottom and depression of the +land is now going on in many parts of the earth's surface. And, +therefore, we shall be assuming nothing beyond the range of +experience if we say that such elevations and depressions went on +during coal measure times. The coal measure times must have been +times during which the same spot was now below the sea, and now dry +land, over and over again. There was a land surface on which plants +grew fast and multiplied rapidly, and as they died fell and +accumulated in a great heap of dead vegetable matter. After a time +this layer of vegetable matter was slowly and gently let down +beneath the waters of the sea--so slowly that the water flowing +over it did not, as a rule, disturb the loose, pasty mass; and +then, by the method I have described to you, shales and sandstones +were deposited on the top of this mass of dead vegetable matter. By +their weight they compressed it, and by certain chemical changes +(which we have not time to go into this evening) this dense mass of +vegetable matter became converted into coal. After a time the +shales and sandstones which had been piled above this stuff, which +was to form coal for the future, were again elevated to form a land +surface; upon this another forest sprang up, and by its decay +produced another mass of vegetable matter fit to form coal. This +again was let down below the water, more shales and sandstones were +deposited on the top, and this process went on over and over again +till the whole mass of our present coal measures was formed. You +will now see how it is that trees are so seldom found in an upright +position in the coal beds. As the land went down, they would in +very many cases be toppled over by the water as it flowed against +them, or their base would be rotted, and they would then either +fall or be blown over; that is the reason why in most cases they +are found lying flat on the roof of the coal bed. But in a few +cases, when the depression was very gentle and gradual, the trees +were not overthrown, and the shales and sandstones accumulated +round them and preserved them in the position in which they +grew.</p> + +<p>I do not know that I can point out to you anything nowadays that +exactly resembles the state of things that must have gone on during +the times these coal measures were being formed; but there are a +great many cases strikingly analogous to them. I shall not attempt +to describe them to you, but may just mention the mangrove swamps +that very often fringe the coasts in the tropics, and the cypress +swamps of the Mississippi, which are so well described by Sir +Charles Lyell in his recent works; also the great Dismal Swamp of +Virginia, which appears to me to furnish the nearest analogue to +the state of things that existed during coal measure times.</p> + +<p>Having explained the way in which coal measures have been +formed, we will now take a brief sketch of its uses and products. +The year 1259 is memorable in the annals of coal mining. Hitherto +the mineral had not been raised by authority, but in that year +Henry III. granted a charter to the freemen of Newcastle-on-Tyne +for liberty to dig coal, and a considerable export trade was +established with London, and it speedily became an article among +the various manufacturers of the metropolis. But its popularity was +but short lived. An impression became general that the smoke +arising therefrom contaminated the atmosphere and was injurious to +public health. Years of experience have proved the fallacy of the +imputation; but in 1306 the outcry became so general that a +proclamation was issued by Edward I forbidding the use of the +offending fuel, and authorizing the destruction of all furnaces, +etc., of those persons who should persist in using it. Prejudice +gradually gave way as the value of the fossil fuel became better +known, and from that time downward its use has become more and more +extended down to the enormous extent of our present trade. The +annual increase in the production of coal in the British Isles +since the year 1854 is over 2½ million tons. In that year +the coal produce was about 65 million tons, and it has grown up to +the year 1880 to the grand total of 135 million tons.</p> + +<p>We will now deal with some of the uses that this valuable black +diamond is now being put to. It is, in the first place, the center +of all our enterprise and prosperity, and upon it depends our chief +success as a manufacturing nation for the future. When it is +exhausted we shall have to look forward to the condition of things +which now obtains in those regions where there is no coal--that is +to say, instead of our being a nation full of manufacturing and +mercantile enterprise, a great nation to which all the people of +the earth resort, we shall be merely a people who live for +ourselves by the cultivation of the ground. The duration of our +coal fields has been ascertained within certain limits. Mr. Hall, +an accomplished geologist, tells us that in England at the present +time we have a stock of coal sufficient for our consumption for no +less than 1,000 years. On the other hand, Professor Jevons, whose +opinion is worthy of the very greatest weight on such questions, +calculates that 100 years is about the tenure of our coal fields, +according to the present rate of increase in the consumption. +Whichever view we take, sooner or later the end must ultimately +come when the coal will be exhausted; when the great mainspring of +our commercial enterprise will be gone, and we shall revert to that +condition in which we were before the coal fields were worked. In +this point of view, therefore, coal has an especial interest to us +as engineers. If coal is important in this direction, it is no less +important in a purely scientific point of view, apart from any +mercantile end.</p> + +<p>The chemist or physicist will tell you the wondrous story that +the black substance which you burn is simply so much light and heat +and motion borrowed from the sun and invested in the tissues of +plants. He will tell you that when you sit round your firesides the +flame which enlivens you, and the gas which enables you to read, +and which civilizes you, is nothing in the world but so much +sunlight and so much sunheat bottled up in the tissues of +vegetables, and simply reproduced in your grates and gas burners. +Very few persons, I am afraid, realize this, which is one of the +many stories which science in its higher teachings shows us--one of +those fairy tales which are the result of the most careful +scientific investigation. Of the hundred and odd million tons of +coal which we in this country burn in the course of a year, about +20,000,000 tons are thrown on our house fires; 30,000,000 tons find +their way into our blast furnaces, or are otherwise used in the +smelting and manufacture of metals; about 48,000,000 are burnt +under steam boilers; 6,000,000 are used in gas-making; while the +remainder is consumed in potteries, glass works, brick and lime +kilns, chemical works, and other sundries which I need not speak +of.</p> + +<p>To go into the chemistry of coal is quite sufficient to take up +more time than I have at my disposal this evening, therefore I will +briefly touch on a few of the main points. Coal gas is made, as you +are all aware, by heating coal or cannel, which is the special form +of coal most valued for the purpose, on account of the high quality +of gas it produces in cylindrical fireclay retorts.</p> + +<p>The by-products obtained in the manufacture of coal gas, the tar +and the ammonia water, are nowadays scarcely less important than +the coal gas itself. The ammonia water furnishes large quantities +of salts to be used, among other applications, as food for plants. +We thus restore to-day to our vegetation the nitrogen which existed +in plants of primeval times. The tar, black and noisome though it +be, is a marvelous product, by the reason of scores of beautiful +substances which are concealed within it.</p> + +<p>Coal tar when distilled yields three main products: naphtha, +dead oil, and pitch or asphalt. The naphtha on redistillation +yields benzine, from which are prepared some of our most beautiful +dyes; the dead oil, as the less volatile portion is termed, +furnishes carbolic acid, used as a disinfectant and antiseptic, +together with anthracene and naphthaline; all three substances the +starting points of new series of coloring matters.</p> + +<p>This discovery of these coloring matters marks an era in the +history of chemical science; it exercised an extraordinary +influence on the development of organic chemistry. Theoretical and +applied chemistry were knit together in closer union than ever, and +dye followed dye in quick succession; after mauve came magenta, and +in close attendance followed a brilliant train of reds, yellows, +oranges, greens, blues, and violets; in fact, all the simple and +beautiful colors of the rainbow.</p> + +<p>But there is still another story of coal tar to be told. Among +the many curious substances that wonderful fluid contains is the +beautiful wax-like body called paraffine, the development of which +chiefly owes its origin to the genius and energy of Mr. James +Young. As early as 1848, Mr. Young had worked a small petroleum +spring in a coal mine in Derbyshire, and had produced oils suitable +for burning and lubricating purposes, but the spring gave out, and +then Mr. Young sought to obtain these oils by distilling coal. +After many trials, in conjunction with other gentlemen connected +therewith, he proved successful, and the present magnitude of this +industry is without parallel in the history of British +manufactures.</p> + +<p>In Scotland alone there are about sixty paraffine oil works, one +alone occupying a site of nearly forty acres. Here about 120,000 +gallons of crude oil are produced weekly, and among the various +works in Scotland about 800,000 tons of shale are distilled per +annum, producing nearly 30,000,000 gallons of crude oil, from which +about 12,000,000 gallons of refined burning oil are obtained in +addition to the large quantities of naphtha, solid paraffine, +ammonia, and other chemical products. Twenty-five years ago +scarcely a dozen persons had seen this paraffine, and now it is +turned out by the ton, fashioned into candles delicately tinted +with colors obtained from coal tar.</p> + +<p>I might dwell on this subject until it becomes wearisome to you, +therefore I will not trespass too much on your time. But from every +point we look we reach this fact, that our coal trade is one which +develops itself according to laws that we are perfectly powerless +to control; if it seems to promise a less rapid increase here, it +is only that it may spread abroad with accelerated vigor elsewhere; +if it is our slave in some aspects, it seems as if it were our +master in others.</p> + +<p>Finally, we have to ask, What of our export coals? Rapid as has +been the growth of our total production during the last +twenty-three years, the growth of our export of coals has been +greater still. Beginning at 4,300,000 tons in '54, we find it +reaching 16,250,000 tons in '76, and an increase at a corresponding +ratio up to the present date as far as statistics will carry us. At +such a rate of increase it would seem as if our whole annual +production would be ultimately swallowed up in our exports, and it +is not, perhaps, impossible that after we have ceased to be to any +great extent a manufacturing people, a certain export trade in coal +may still continue. Just the same as the export trade in coal +preceded by centuries our own uses for it other than domestic, so +may it also survive these by a period as prolonged. If our descent +from our present favored position be a gradual one, much may be +done in the interval to adapt ourselves to the future outcome, but +it is certain that nothing will be done except under the stern +persuasion of necessity.</p> + +<p>When our coal fields become exhausted, be it soon or late, he +would be a wise or, perhaps, a rash speculator who fixed himself to +a year or a generation. Being inevitable, the best philosophy is to +make our decline more gradual and less bitter. Sentimental regrets +that these hills and valleys will no longer resound with the din of +labor, or be blackened by the smoke of the factory, would surely be +out of place. What we might regret is that Britain, which we know +and are proud of, the Britain of great achievements in politics and +literature, of free thought and self-respecting obedience, of a +thousand years of high endeavor and constant progress, was indeed +to perish when these factories and furnaces whirled and blazed +their last. But, it is not so. This country's fortunes are +gradually being merged into those of a Greater Britain, which +largely, through the aid of coal, whose prospective loss we are +lamenting, has grown beyond the limits of these islands to +overspread the vastest and richest regions of the earth; and we +have no reason to fear that the great inheritance that America and +Australia and New Zealand have accepted from us will in their hands +be dealt unworthily with in the future.</p> + +<hr> +<p><a name="27"></a></p> + +<h2>GASTON PLANTE.</h2> + +<p>This eminent scientist was born in Orthez (Department of +Basses-Pyrénées) on the 22d of April, 1834; at +present in his fiftieth year. He began his scientific career as +assistant to Edmund Becquerel at the Conservatoire des Arts et +Métiers at Paris. In the year 1859, after resigning his +position at the above named institution, he entered upon his +researches in electricity, and has continued them ever since. His +work entitled "Recherches sur l'Electricité" is a model of +clear language and elegant demonstration, and contains all the +papers presented by Planté to the Paris Academy of Sciences +since 1859.</p> + +<p class="ctr"><img src="images/9a.png" alt= +"GASTON PLANTE."></p> + +<p class="ctr">GASTON PLANTE.</p> + +<p>At the Paris Electrical Exhibition in 1881, Planté +received a Diploma of Honor, the highest distinction conferred, +while in the same year the Academy of Sciences voted him the +"Lacaze" prize, and the Society for the Encouragement of National +Industry presented him with the "Ampère" medal, its highest +award.</p> + +<p>Planté deserves not only the honors conferred upon him by +his own country, but those of the world on account of his +cosmopolitan character--a rarity among his countrymen. He sends his +apparatus to all exhibitions of any consequence; they appeared at +Munich and Vienna, where their interpretation by the attendant +added considerably to the renown of their author.--<i>Zeitch f. +Elektrotechnik</i>.</p> + +<hr> +<p><a name="28"></a></p> + +<h2>WARREN COLBURN.</h2> + +<p>Warren Colburn, the eminent American mathematician, was born in +Dedham, Mass., March 1, 1793.</p> + +<p>He was the eldest son of a large family of children. His parents +were poor, and "Warren" was, during his childhood, frequently +employed in different manufacturing establishments to aid the +family by his small earnings.</p> + +<p>In early boyhood he manifested an unusual taste for mathematics, +and in the common district school was regarded as remarkable in +this department. He learned the trade of a machinist, studying +winters, until he was over twenty-two years of age, when he began +to fit for Harvard College, which he entered in 1817 and graduated +with high honors in 1820. He taught school in the winter months, +while in college, in Boston, Leominster, and in Canton, Mass. From +1820 to 1823 he taught a select school in Boston.</p> + +<p>While in college he was regarded as by far the best +mathematician in his class, and during this period thought there +was the necessity for such a book as his "First Lessons in +Intellectual Arithmetic." This conviction had been forced upon his +mind by his experience in teaching. In the autumn of 1821 he +published his "first edition." His plan was well digested, although +he was accustomed to say that "the pupils who were under his +tuition made his arithmetic for him;" that the questions they asked +and the necessary answers and explanations which he gave in reply +were embodied in the book, which has had a sale unprecedented for +any book on elementary arithmetic in the world, having reached over +2,000,000 copies in this country, and the sale still continues, +both in this country and in Great Britain. It has been translated +into most of the European languages and by missionaries into many +Asiatic languages.</p> + +<p>After teaching in Boston about two and one-half years, he was +chosen superintendent of the Boston Manufacturing Company's works +at Waltham, Mass., and accepted the position; and in August, 1824, +owing to the mechanical genius he displayed in applying power to +machinery, combined with his great administrative ability, he was +appointed superintendent of the Lowell Merrimac Manufacturing Co., +at Lowell, Mass. Here he projected a system of lectures of an +instructive character, presenting commerce and useful subjects in +such a way as to gain attention and enlighten the people.</p> + +<p>For several years he delivered gratuitous lectures on the +Natural History of Animals, Light, Electricity, the Seasons, +Hydraulics, Eclipses, etc. His knowledge of machinery enabled him +admirably to illustrate these lectures by models of his own +construction; and his successful experiments and simple teaching +added much to the practical knowledge of his operatives.</p> + +<p>He proposed to occupy the space between the common schools and +the college halls by carrying, so far as might be practicable, the +design of the Rumford Lectures of Harvard into the community of the +actual workers of common life.</p> + +<p>In the mean time he discharged his official duties efficiently, +and the superintendence of the schools of Lowell was also added to +his labors. He never relinquished, during these busy years, the +design formed in his college days of furnishing to the children of +the country a series of text-books on the <i>inductive plan</i> in +mathematics.</p> + +<p>His "Algebra upon the Inductive Method of Instruction," appeared +in 1825, and his "Sequel to Intellectual Arithmetic" in 1836. He +regarded the "Sequel" as a book of more merit and importance than +the "First Lessons."</p> + +<p>He also published a series of selections from Miss Edgeworth's +stories, in a suitable form for reading exercises for the younger +classes of the Lowell schools, in the use of which the teachers +were carefully instructed.</p> + +<p>In May, 1827, he was elected a Fellow of the American Academy of +Sciences. For several years he was a member of the Examining +Committee for Mathematics at Harvard College.</p> + +<p>He was a member of the Superintending School Committee of +Lowell; and so busy were he and his coworkers that they were +repeatedly obliged to hold their meetings at six o'clock in the +morning.</p> + +<p>Warren Colburn was ardently admired--almost revered--by the +teachers who were trained to use his "Inductive Methods of +Instruction" in teaching elementary mathematics.</p> + +<p>In personal appearance Mr. Colburn was decidedly pleasing. His +height was five feet ten, and his figure was well proportioned. His +face was one not to be forgotten; it indicated sweetness of +disposition, benevolence, intelligence, and refinement. His mental +operations were not rapid, and it was only by great patience and +long continued thought that he achieved his objects. He was not +fluent in conversation; his hesitancy of speech, however, was not +so great when with friends as with strangers. The tendency of his +mind was toward the practical in knowledge; his study was to +simplify science, and to make it accessible to common minds.</p> + +<p>Mr. Colburn will live in educational history as the author of +"Warren Colburn's First Lessons," one of the very best books ever +written, and which, for a quarter of a century, was in almost +universal use as a text-book in the best common schools, not only +in the primary and intermediate grades, but also in the grammar +school classes.</p> + +<p>In accordance with the method of this famous book, the pupils +were taught in a natural way, a knowledge of the fundamental +principles of arithmetic. By its use they developed the ability to +solve mentally and with great facility all of the simple questions +likely to occur in the every day business of common life.</p> + +<p>Undoubtedly Pestalozzi first conceived the idea of the true +"inductive method" of teaching numbers; but it was Mr. Colburn who +adapted it to the needs of the children of the common elementary +schools. It has wrought a great change in teaching, and placed +Warren Colburn on the roll as one of the educational benefactors of +his age.</p> + +<p>He died at Lowell, Mass., Sept. 13, 1883, at the age of 90 +years.--<i>Journal of Education</i>.</p> + +<hr> +<p><a name="10"></a></p> + +<h2>THURY'S DYNAMO-ELECTRIC MACHINE.</h2> + +<p>Thury's dynamo-electric machine, which presents some +peculiarities, has never to our knowledge been employed outside of +Sweden and a few neighboring regions; but this is doubtless due to +some personal motive or other of its constructors, since it has, it +would seem, given excellent results in every application that has +been made of it. It is represented in perspective in Fig. 1, and in +longitudinal section and elevation in Figs. 2 and 3.</p> + +<p>As may be seen, it is a multipolar (6-pole) machine in which an +attempt has been made to utilize magnetically, as far as possible, +all the iron used in the frame. For this reason the system has been +given the form of a hexagonal prism, whose faces are formed of flat +electro-magnets, A, A, xxx, constituting the inductors.</p> + +<p>The internal angles of this prism are filled by polar +expansions, P, P, xxx, alternately north and south, that thus form +in the interior of the apparatus an inscribed cylinder designed to +receive the armature. This latter belongs to the kinds that are +wound upon a cylinder in which the wire is external thereto.</p> + +<p>The conductors are placed upon the iron drum longitudinally and +parallel with its axis. But instead of being connected with each +other at the posterier end of the armature, as in the Siemens +system, they are connected according to chords that correspond to a +fourth, a sixth, or any equal fraction whatever of the +circumference. Fig. 4 gives a perspective view of the cylinder, +upon which the conductors 1, 2, 3, 4, and so on, are placed +according to generatrices. The armature is supposed to be divided +into six parts, each conductor passing over the bases of the drum +through a chord equal to the radius, that is to say, corresponding +to a sixth of the circumference.</p> + +<p>Three conductors are all connected together in such a way as to +form but a single circuit closed upon itself. Conductor 1, for +example, is connected with No. 6 in such a way that the end issuing +from 1 becomes the end that enters No. 6. Conductor No. 3 is +connected in the same way with No. 8, and so on, up to the last +conductor, which is connected in its turn with the end that enters +the first.</p> + +<p>As the figure shows, the conductor before passing from 3 to 8, +for example, returns several times upon itself in following 6 and +3, and the same is the case with all the rest of the winding.</p> + +<p class="ctr"><img src="images/10a.png" alt= +"FIG. 1. PERSPECTIVE VIEW OF THE THURY MACHINE."></p> + +<p class="ctr">FIG. 1. PERSPECTIVE VIEW OF THE THURY MACHINE.</p> + +<p>In this way the cylinder becomes inclosed within nine +rectangular wire frames, each of which is connected with the +following one by a conductor that is at the same time connected +with one of the nine plates of the collector. The number of the +rubbers corresponds to that of the inducting poles. They may be +coupled in different ways, but they are in most cases united for +quantity.</p> + +<p>It will be seen that the Thury armature resembles, in the system +of winding, those of the Siemens machines and their derivatives. +But it differs from these, however, in the details connected with +the coupling of the wires, from the very fact that the features of +a two-pole machine are not found exactly in a multipolar one.</p> + +<p class="ctr"><img src="images/10b.png" alt= +"FIGS. 2 AND 3."></p> + +<p class="ctr">FIGS. 2 AND 3.</p> + +<p>This latter kind of machine is considered advantageous by its +inventors, in that there is no need of revolving it with much +velocity. It must not be forgotten, however, that although we +reduce the velocity by this mode of construction, we are, on +another hand, obliged to increase the size of the machine, so that, +according to the circumstances under which we chanced to be placed, +the advantage may now be on the one side and now on the other.</p> + +<p class="ctr"><img src="images/10c.png" alt= +"FIGS. 4 AND 5."></p> + +<p class="ctr">FIGS. 4 AND 5.</p> + +<p>It goes without saying that Fig. 4 is essentially diagrammatic, +and is designed to give a clearer idea of the mode of winding the +armature. In practice the number of the frames, and consequently +that of the plates of the conductor, is much greater, and the +arrangement that we have described is repeated a certain number of +times, the conducter always forming a circuit that is closed upon +itself.</p> + +<p>The Thury machines are constructed in different styles. No. 1 is +a 100-lamp (16 candles and 100 volts) machine, and Nos. 2 and 3 are +nominally 250-lamp ones, but may be more. Their weight is 1,100 +kilogrammes, and their velocity, for 100 volts, is from 400 to 500 +revolutions, according to the mode of coupling.</p> + +<p>A later type, now in course of construction, is to furnish from +750 to 2,000 lamps, with 250 revolutions, for 100 volts, and is not +to weigh more than 2,000 kilogrammes. Let us add that Messrs. +Meuron and Cuenod, the manufacturers, have likewise applied their +mode of winding to conductors arranged radially upon the surface of +a circle. Fig. 5 shows this arrangement.</p> + +<p>In this case the inductors will, it is unnecessary to say, be +arranged laterally as in all flat ring machines. The arrangement +will recall, for example, that of the Victoria machines +(Brush-Mordey).</p> + +<p>We do not think that the inventors have applied this radial +arrangement practically, for it does not appear to be advantageous. +The parts of conductors which are perpendicular to the radius, and +which can be only inert (even if they do not become the seat of +disadvantageous currents), have, in fact, too great an importance +with respect to the radial parts.--<i>A. Guerout, in La Lumiere +Electrique</i>.</p> + +<hr> +<p><a name="11"></a></p> + +<h2>BREGUET'S TELEPHONE.</h2> + +<p>Prof. G. Forbes gives the following description: The instrument +which I call Breguét's telephone is founded upon the +instrument which was described by Lipmann, called the capillary +electrometer. The phenomenon may be shown in a variety of ways. One +of the easiest methods to show it is by taking a long glass tube +and bending it into two glasses of dilute acid, and, the tube being +filled with acid itself, a piece of mercury is placed in the center +of the tube. Then if one pole of a battery is connected with one +vessel of acid, and the other pole of the battery is connected with +the other vessel of acid, at the moment of connection the bit of +mercury will be seen to travel to the right or left, according to +the direction of the current. M. Lipmann explained the action by +showing that the electro-motive force which is generated tends to +alter the convexity of the surface of the mercury. The surface of +the mercury, looked at from one side, has a convex form, which is +altered by the electro-motive force set up when connection is made +with the battery. The equilibrium of the mercury is dependent upon +the convexity, and consequently when the convexity is disturbed the +mercury moves to one side or the other. Lipmann also showed that if +a tube containing a bit of mercury, and tapering to a point, is +taken and dipped into acid, and then the tube filled with acid, on +one pole of a battery being dipped into the tube and another into +the acid the mercury will move up or down, showing similar action +to that which I have just described.</p> + +<p>Lipmann further showed the reverse effect, that if a piece of +mercury be forcibly pressed, so as to alter the convexity of its +surface, such as by bringing it into a narrower part of the tube, +then there is an electro-motive force produced.</p> + +<p>It occurred to me, and no doubt it did to Breguet also, that if +we speak either against the surface of the glass tube, and caused +the tube to vibrate, or if the mercury were caused to vibrate in +the manner I have shown, we ought to be able to introduce a varying +current in the wires which might have sufficient electro-motive +force to produce audible speech in a Bell telephone. Further, the +same instrument, since varying electro-motive force affected the +drop of mercury and produced varying displacement, ought also to +act as a receiving instrument, and should vibrate in accordance +with the currents that arrive. My experiments have only been in the +way of using the instrument as a transmitter; but Breguét, I +find, used it as a receiver as well as a transmitter, though I am +not aware that M. Breguet made any actual experiments so as to +produce articulate speech. I presume that this was done, although I +have not come across any description of the experiments, and it was +for that reason that I thought possibly some account of my own +experiments might be interesting to the members of the Society. The +first tubes that I used were bits of glass tube about a centimeter +diameter, and simply drawn out to a tapering point. I have the +tubes here. The first experiment I tried was by tapping the glass +tube so as to mechanically shift the position of the mercury, and +by listening on the telephone for the effect. For a long time, at +least an hour, I could get no effect at all. At last I got a sound, +but could not understand how it was that at one time of tapping I +could not hear, while at another time it was quite loud.</p> + +<p>At the top I always got sound, but at the side I got no sound, +although the mercury was shaking. I then tried to see how feeble a +current was audible in the telephone. An assistant tapped the tube +while I stood out of the way, and where I could not see. I got him +to tap it gentler and gentler, and could hear the most feeble tap. +A pellet of paper was next dropped from various heights down to an +inch, and each tap was perfectly audible in the telephone. I tried +many methods, and one, purely accidentally chosen, was a piece of +glass tube which I had drawn out into a tube about 2 mm. diameter, +and then nearly closed the end of it. I have that tube here, and +you will see what an ill-shapen and ugly-looking tube it is, but it +is one of the best tubes I ever got; and finally, I found that +small bits of thermometer tube, which were simply closed at their +ends with a blow-pipe, gave very good results, and I was able to +make them useful for various purposes. I then tried mounting a tube +on the end of a speaking-trumpet and speaking to the mercury, but +got no effect. In every place where I attached the glass tube +itself to a sounding-board I got a very accurate reproduction. I +put one on a piece of ferrotype plate, and that gave really the +best result I ever got. The tube was fastened with sealing-wax, and +with it I got excellent speech heard in a Bell receiver. I tried +putting in a large number of these tubes, all in quantity, on the +bottom of a ferrotype plate, but with no advantage. I have not yet +tried putting them in series, one behind the other, so as to +increase the electro-motive force, but I think that probably would +be an improvement; of course it would require many vessels of +acidulated water to dip into. The most distinct articulate speech +was obtained from an ordinary ferrotype telephone plate, secured at +the edges, and one of the glass tubes you see here attached to +it.</p> + +<hr> +<p><a name="12"></a></p> + +<h2>MUNRO'S TELEPHONIC EXPERIMENTS.</h2> + +<p>Mr. J. Munro, whose name is well known not only as a very clear +writer upon electrical subjects, but as an original investigator, +has recently, with the assistance of Mr. Benjamin Warwick, been +conducting a most interesting experimental investigation of the +action of the microphone as a telephonic transmitter, with the +result of proving that metals may advantageously be employed in the +place of carbon in a transmitting instrument, a practical +development of one of the very earliest of Professor Hughes' +microphones. The fact that metallic electrodes can practically be +employed in microphonic transmitters has been denied of late with +so much assurance and in such high quarters, that Mr. Munro's +successful applications of that portion of Professor Hughes' +discovery possess an especial interest, and must to a considerable +extent affect the aspect of litigation in future contests in which +the discovery of the microphone and the invention of the carbon +transmitter are vital points at issue.</p> + +<p>In investigating the properties of metallic conductors employed +in the construction of microphones, Mr. Munro's first experiments +were made with wires. These, in some cases, were caused by the +action of a diaphragm, to rub the one on the other in such a manner +as to make the point of contact vary (under the influence of the +vibrations of the diaphragms) on one side or other of a position of +normal potential, so that by the movement of a wire attached to a +vibrating tympan along a fixed wire conveying a current from a +battery, and thereby shunting the current at various positions +along the length of the fixed wire, the strength of the current in +the derived circuit, in which was included a suitable receiver, was +varied accordingly. In other experiments mercury was employed, +either as a sliding-drop, inclosing the fixed wire, or as an +oscillating column; but these experiments, though instructive and +interesting, did not for various reasons give encouraging results +with a view to the practical application of the principle.</p> + +<p>They, however, led Mr. Munro to proceed with compound wire +structures, such as gratings resting upon or rubbing against one +another, and one of the first experiments in this direction proved +very successful, and led Mr. Munro to the construction of his gauze +telephone, which is the most characteristic and efficient of his +practical apparatus.</p> + +<p>This instrument consists essentially of two pieces of iron-wire +gauze, the one fixed in a vertical plane, and the other resting +more or less lightly against it, the pressure between them being +regulated by an adjustable spring or weight. These gauze plates are +so connected in a telephonic circuit as to constitute the +electrodes of a microphone; for touching one another lightly in +several points, they allow the current to be transmitted between +them in inverse proportion to the resistance offered to it in its +passage from one to the other. Under the influence of sonorous +vibrations the one plate dances more or less on the other, thus +varying the resistance; and very perfect articulation is produced +in a telephonic receiver included in the circuit. The gauze +transmitter so constructed may be fixed within a wall-box with or +without a mouthpiece; but as the sound waves acting directly upon +the gauze plates set them into agitation through their sympathetic +vibration or by direct impact, no sort of diaphragm or equivalent +device is necessary, and none is employed.</p> + +<p class="ctr"><img src="images/11a.png" alt= +"FIG. 1."></p> + +<p class="ctr">FIG. 1.</p> + +<p>A convenient form of this apparatus is shown in Fig. 1, and to +which the name of "The Lyre Telephone" has been given from its +resemblance to that impossible musical instrument. In this +apparatus, G¹ is a plate of iron wire gauze stretched +vertically between two horizontal wires attached to a lyre-shaped +framework of mahogany; against the plate rests the smaller plate, +G², the normal pressure between them being regulated by an +adjustable spring acting in opposition to a weighted lever, W. The +two plates are connected respectively with the attachment screws, X +and Y, by which the instrument is placed in a circuit with a +battery and telephonic circuit.</p> + +<p class="ctr"><img src="images/11b.png" alt= +"FIG. 2."></p> + +<p class="ctr">FIG. 2.</p> + +<p>A modification of this apparatus is shown in the diagram sketch, +Fig. 2, which will probably be a more practical form. In this +instrument the electrodes consist of two circular disks of iron +wire gauze of different diameters, the larger disk, G¹, which +is fixed, being pierced with holes of smaller diameter than the +smaller disk, G². In the diagram the two disks are shown +separated for the purpose of explanation, but in reality they rest +the one against the other; the smaller and movable disk, G², +is held up against G¹ with greater or less pressure by the +spiral spring, S, the tension of which can be adjusted by a screw +or other suitable device at N. This form of the apparatus is more +suitable for inclosure in a wall box with or without a mouthpiece, +but it does not require the employment of any kind of diaphragm or +tympan. Mr. Munro can employ with all his instruments an induction +coil for installations where the resistance of the line wire makes +it desirable to do so; the microphone and battery being included in +the primary circuit and the telephones in the secondary.</p> + +<p class="ctr"><img src="images/11c.png" alt= +"FIG. 3."></p> + +<p class="ctr">FIG. 3.</p> + +<p>Fig. 3 is an ingenious arrangement devised by Mr. Munro, in +which the adjusting spring or weight is substituted by a magnet +which may be either a permanent or an electro-magnet. The figure +shows an arrangement in which the fixed gauze, g¹, is +perforated as in the apparatus illustrated in Fig. 2, and the +movable electrode, g, is bent or dished so as to press upon g¹ +around its edge. E is a magnet which by its attractive influence +upon g holds t up against g¹ with a pressure dependent upon +its magnetic intensity and upon its distance from the gauze. By +making E an electro-magnet, and including its coil in the +telephonic circuit, an instrument may be constructed in which the +normal pressure between the electrodes can be automatically +adjusted to the strength of the current, and in cases where an +induction coil is employed the magnet, E, may be the core of such a +coil.</p> + +<p class="ctr"><img src="images/11d.png" alt= +"FIG. 4."></p> + +<p class="ctr">FIG. 4.</p> + +<p>Fig. 4 illustrates an apparatus devised by Mr. Munro, and to +which the name thermo-microphone might be given, as it is a +microphone in which thermo-electric currents are employed in the +place of voltaic currents, its special feature of interest lying in +the fact that the heated junction of the thermo-electric couple is +identical with the microphone contacts of the two electrodes. In +this very elegant experiment a piece of iron wire gauze, G, is +supported in a horizontal position by a light metallic support, B. +To another support. A, is loosely hinged a frame, which at its +further extremity carries a little coil of German silver wire, C, +which by its weight rests upon the center of the gauze plate, G; +and in contact therewith, and to increase the pressure of contact, +a little bar weight is laid within the convolutions of the core. +The two electrodes, the gauze, and the coil are connected, as +shown, to a receiving telephone, T. Upon the application of heat, +as from the flame of a spirit lamp placed below, a thermo-electric +current is set up throughout the circuit; in this condition the +apparatus becomes a very perfect microphone, and when the pressure +between the electrodes is properly adjusted it is a very efficient +telephonic transmitter, transmitting articulate speech and musical +sounds with remarkable clearness and fidelity.</p> + +<p class="ctr"><img src="images/11e.png" alt="FIG. 5"></p> + +<p class="ctr">FIG. 5</p> + +<p>Mr. Munro is, with the aid of Mr. Warwick's manipulative skill, +extending this portion of his investigation further by +experimenting with gauzes and coils of various metals forming other +couples in the thermo-electric series, as well as with iron and +other gauzes electrotyped with bismuth and other metals, and we +hope in due time to lay the results of those experiments before our +readers.</p> + +<p>Mr. Munro has, moreover, observed that if two pieces of gauze of +identical material and in microphonic contact be heated, a peculiar +sighing sound is heard in a telephone connected with them and with +a battery, and he attributes this phenomenon to the electrical +discharge between the gauze plates being facilitated and increased +by the action of heat, but we are rather inclined to trace the +effect to the mechanical action of the one gauze moving over the +other under the influence of expansion and contraction of the +metals by the variable temperature of the flame and convection +currents of heated air, such movement producing the sounds just as +would be produced if one of the electrodes of an ordinary +microphone were as delicately moved by the hand or other agent.</p> + +<p class="ctr"><img src="images/11f.png" alt="FIG. 6"></p> + +<p class="ctr">FIG. 6</p> + +<p>Figs. 5 and 6 illustrate another and distinct form of metallic +microphone transmitter designed by Mr. Munro and Mr. Warwick, in +which a small chain, preferably of iron, forms the microphonic +portion of the apparatus. In Fig. 5, A is a plate of sonorous wood +forming a diaphragm or collector of the sonorous waves; to the back +of this is attached a short length of chain, C, the opposite ends +of which are by the wires, X and Y, included in the telephonic +circuit. The points of junction of the links with one another +constitute the variable microphonic contacts, and the normal +pressure between them is adjusted by the spiral spring, S, the +tension of which may be varied by the cord and winding pin, B. Fig. +6 is the section of a transmitter constructed upon this principle, +and in which two chains, c and c', are employed attached at one end +by a wire, f, to a diaphragm mouthpiece, N, and at their opposite +extremities to the adjusting springs, s and s'; an induction coil, +D, may be employed if the resistance of the line render it +advantageous.</p> + +<p class="ctr"><img src="images/11g.png" alt="FIG. 7"></p> + +<p class="ctr">FIG. 7</p> + +<p>Fig. 7 is a form of pencil microphone experimented with by Mr. +Munro, which differs from some of the Hughes' transmitters adopted +by Crossley, Gower, Ader, and many others only in the material of +which it is composed, Mr. Munro's being of cast iron, while the +others to which we have referred are of carbon rods such as are +used in electric lighting. In Fig. 7 a light cast-iron bar, +i², of the form shown, is supported in holes drilled in two +blocks of cast iron, i i', and the pressure between the bar and the +blocks can be adjusted by a regulating spring, s. In connection +with this apparatus Mr. Munro has observed that rust has no +appreciable effect upon the efficiency of the instrument unless it +be to such an extent as to cause the two to adhere, or to be +"rusted up" together.</p> + +<p class="ctr"><img src="images/11h.png" alt="FIG. 8"></p> + +<p class="ctr">FIG. 8</p> + +<p>We now come to another class of metallic transmitters with which +Mr. Munro and his associate have been making experiments, and to +which he has given the name "Grain transmitter," since it consists +of a box having metallic sides, e e', to which terminal screws, t +t', are attached and filled in between with iron or brass filings, +granules of spongy iron, or indeed small metallic particles in any +form; one of the most efficient transmitters being a box such as is +shown in Fig. 8, filled with a quantity of ¼ in. screws.</p> + +<p class="ctr"><img src="images/11i.png" alt="FIG. 9"></p> + +<p class="ctr">FIG. 9</p> + +<p>The results of Mr. Munro's experiments have led him to the +opinion that the action of the microphone must be attributed to the +action of sonorous vibrations upon the air or gaseous medium +separating the so-called contact-points of the electrodes, and that +across these spaces, or films of gaseous matter, silent electrical +discharges take place, the strengths of which, being determined by +the thickness of the gaseous strata through which they pass, vary +with the motion of the electrodes; and as, according to this +hypothesis, the distances of the electrodes from one another is +determined by the sound-waves, the sound in that way controls the +current.--<i>Engineering</i>.</p> + +<hr> +<p><a name="13"></a></p> + +<h2>APPARATUS FOR MANEUVRING BICHROMATE OF POTASSA PILES FROM A +DISTANCE.</h2> + +<p>Bichromate of potassa piles, especially those single liquid ones +that are applied to domestic lighting, all present the grave defect +of consuming almost as much zinc in open as in closed circuit, and +of becoming rapidly exhausted if care be not taken to remove the +zinc from the liquid when the battery is not in use. This +operation, which is a purely mechanical one, has hitherto required +the pile to be located near the place where it was to be used, or +to have at one's disposal a system of mechanical transmission that +was complicated and not very ornamental.</p> + +<p>In order to do away with this inconvenience, which is inherent +to all bichromate piles, Mr. G. Mareschal has invented and had +constructed an ingenious system that we shall now describe.</p> + +<p class="ctr"><a href="images/12a.png"><img src= +"images/12a_th.jpg" alt=""></a></p> + +<p class="ctr">FIG. 1.--BICHROMATE OF POTASSIUM PILE, WITH<br> +MANEUVERING APPARATUS.</p> + +<p>Mr. Mareschal's plan consists in suspending the frame that +carries all the battery zincs (Fig. 1) from the extremity of a +horizontal beam, and balancing them by means of weights at the +other extremity.</p> + +<p>The system, being balanced, the lifting or immersion of the +zincs then only requires a slight mechanical power, such as may be +obtained from an ordinary kitchen jack through a combination that +will be readily understood upon reference to Fig. 2. The axis, M, +of the jack, on revolving, carries along a crank, MD, to which is +fixed a connecting-rod, A, whose other extremity is attached to the +horizontal beam that supports the zincs and counterpoises. If the +axle, M, be given a continuous revolution, it will communicate to +the rod, A, an upward and downward motion that will be transmitted +to the beam and produce an alternate immersion and emersion of the +zincs.</p> + +<p>Upon stopping the jack at certain properly selected positions of +the rod, MD, the zincs may, at will, be kept immersed in the +liquids, or <i>vice versa</i>. This is brought about by Mr. +Mareschal in the following way: The jack carries along in its +motion a horizontal fly-wheel, V, against whose rim there bears an +iron shoe, F, placed opposite an electro-magnet, E. In the ordinary +position, this shoe, which is fixed to a spring, bears against the +felly of the wheel and stops the jack through friction. When a +current is sent into the electro-magnet, E, the brake shoe, F, is +attracted, leaves the fly wheel, and sets free the jack, which +continues to revolve until the current ceases to pass into the +electro.</p> + +<p class="ctr"><img src="images/12b.png" alt= +"FIG. 2.--PRINCIPLE OF THE APPARATUS."></p> + +<p class="ctr">FIG. 2.--PRINCIPLE OF THE APPARATUS.</p> + +<p>The problem, then, is reduced to sending a current into the +electro and in shutting it off at the proper moment. This result is +obtained very simply by means of an auxiliary Leclauche pile. (The +piles got up for house bells will answer.) The current from this +pile is cut off from the electro, F, by means of a button, B, when +it is desired to light or extinguish the lamps. In a position of +rest, for example, the crank, MD, is vertical, as shown in the +diagram to the right in Fig. 2. The circuit is open between M and N +through the effect of the small rod, C, which separates the spring, +R, from the spring, R'. As soon as the circuit has been closed, be +it only for an instant, the crank leaves its vertical position, the +rod, C, quits the bend, S, and the spring, R, by virtue of its +elasticity, touches the spring, R', and continues its contact until +the crank, MD, having made a half revolution, the rod, C', repulses +the spring, R, and breaks the circuit anew. The brake then acts, +and the crank stops after making a revolution of 180°, and +immersing the zincs to a maximum depth. In order to extinguish the +lamp, it is only necessary to press the button, B, again. The axle, +M, will then make another half revolution, and, when it stops, the +zinks will be entirely out of the liquid. The depth of immersion is +regulated by fixing the crank-pin. D, in the apertures, +T<sub>1</sub>, or T<sub>2</sub>, of the connecting rod. This +permits the travel, and consequently the degree of immersion, to be +varied.</p> + +<p>The device requires three wires, two for connecting the lamp +with the battery, and one for maneuvering the apparatus through a +closing of the contact, B.</p> + +<p>With Mr. Mareschal's system, bichromate of potassa piles may be +utilized in a large number of cases where a light of but short +duration is required until the battery is exhausted, without the +tedious maneuvering of a winch and without inconvenience. The jack +permits of a large number of lightings and extinctions being +effected before it becomes necessary to wind up its clockwork +movement. This operation, however, is very simple, and may be +performed every time the battery is visited in order to see what +state it is in.</p> + +<p>We regard Mr. Mareschal's apparatus as an indispensable addition +to every case of domestic electric lighting in which bichromate of +potassa piles are used, and, in general, to all cases where the +pile becomes uselessly exhausted in open circuit. It will likewise +find an application in laboratories, where the bichromate pile is +in much demand because of its powerful qualities, and where it is +often necessary to order it from quite a distant point.--<i>La +Nature</i>.</p> + +<hr> +<p><a name="14"></a></p> + +<h2>MAGNETIC ROTATIONS.</h2> + +<h3>By E. L. VOICE.</h3> + +<p>The remarkable researches and experiments of Professor Hughes +clearly show that magnetism is totally independent of iron, and +that its molecules, particles, or polarities are capable of +rotation in that metal. It would also appear that by reason of the +friction between magnetism and iron, the molecules of the latter +are only partially moved, such movement being the result of the +tendency of iron to retard magnetic change.</p> + +<p>I have found that the magnetic molecules also possess inertia, +that they are capable of acquiring momentum, and that their +rotation continues for a considerable time after the exciting cause +of their rotation has ceased.</p> + +<p>These facts may be proved in a very evident manner, inasmuch as +induced electric currents are generated by this <i>after</i> +rotation, which may be made to light incandescent lamps.</p> + +<p>In this case the magnetic rotations are produced in an electro +magnet by means of alternate currents supplied by alternating +Gramme machine.</p> + +<p>In order to better explain the action, it will be necessary to +refer to a new electro-motor, which was the subject of an article +in the <i>Electrical Review</i> of February 19 last. It is of that +type of motor in which the field magnet and armature poles are +alternately arranged, and which requires a periodical reversibility +of magnetism in the armature to cause the latter to revolve, as in +the Griscom motor. The insulating strips in the commutator are +sufficiently wide to demagnetize the whole of the machine before +reversibility in the armature takes place, and this demagnetization +sets up a <i>direct</i> induced current, which is caught in a shunt +circuit by the aid of a second commutator, which only comes into +action when the first commutator goes out.</p> + +<p>When this motor is supplied by a continuous current, it is easy +to understand that the induced current which passes through the +shunt circuit, and which is caused by the demagnetization, is +proportional to the mass of iron and wire of which the machine is +composed, or proportional to its inductive capacity. This current +is purely a secondary effect, of short duration, and only occurs +once at each break of the commutator.</p> + +<p>The motor is of such a size that when supplied with a continuous +current of proper strength the induced electrical effect in the +shunt circuit will light one incandescent lamp. If, however, it is +supplied with an alternating current of the same power, it will +light eight lamps, and the mechanical power given off is even more +than with a continuous current, provided that the alternations from +the dynamo do not exceed 6,000 a minute.</p> + +<p>At first I was considerably puzzled by this great difference, +because in both cases it is impossible for the lamp circuit to be +acted upon by the main current. It occurred to me, however, that +the rapid alternations of the exciting current from the dynamo, and +the consequent speed of magnetic molecular rotation, gave the +latter a certain momentum, and that by widening the insulating +strips of the first or main current commutator, and proportionately +increasing the width of conducting surface in the shunt commutator +up to certain limits, this effect would be increased. I found such +to be the case, from which I inferred that the increase of induced +current in the shunt circuit was on account of its longer duration, +by reason of the acquired momentum of the magnetic molecular +rotations <i>after</i> the alternating exciting current had +ceased.</p> + +<p class="ctr"><img src="images/12c.png" alt=""></p> + +<p>Those who have facilities for carrying out experiments may prove +it in the following manner:</p> + +<p>E, in the inclosed drawing, is an electro-magnet whose brushes +press on two metallic bands, B and B¹, fixed to but insulated +from the spindle, A. The band, B, is in electrical circuit with the +shunt commutator, S, and the main commutator, M; while the band, +B¹, is in contact with shunt commutator, S¹, and main +commutator, M¹. This contact is made by conducting rods, as +indicated. The commutators, as regards their brushes, are so +arranged that when M and M¹ are in action, S and S¹ are +out of action, and <i>vice versa</i>. The spindle and commutators +are rotated by the pulley, P. L is an incandescent lamp in the +shunt circuit.</p> + +<p>Let us now suppose the apparatus at rest, and the brushes in +electrical contact with the main commutators, M and M¹. The +current from an alternating dynamo passes into the magnet, E, and +rapidly reverses its polarity. By actuating the pulley, P, the +commutators are rotated, when M and M¹ go out of, and the +shunt commutators, S and S¹, come into action, enabling the +<i>after</i> current set up in the magnet to light the lamp, L, in +the shunt circuit.</p> + +<p>In order to make comparative tests, the same apparatus may be +supplied with continuous instead of alternating currents. The after +current in the former case, however, is much smaller, consisting of +one electrical impulse only at each break of the commutator, +whereas in the alternating system these impulses are practically +continued; the result being that, all things being equal, a far +greater number of lamps may be used in the shunt than when supplied +by continuous current only, and it would appear that this +difference can only be attributed to the fact that the rotatory +motion of magnetic molecules, or polarity of the magnet, E, +acquires momentum when acted upon by a suitable physical cause, +such as alternating currents of electricity; this momentum lasting +a sensible time after the cessation of the acting cause.</p> + +<p>If we had the gift of magnetic sight, and could see what is +going on in the electro-magnet when it is excited by alternating +currents, we should probably see the molecules or polarities +tumbling over each other at an enormous rate. I do not think, +however, that we should see anything but a vibratory motion as +regards the iron molecules.--<i>Elec. Review</i>.</p> + +<hr> +<p>[AMER. MICROSCOP. JOUR.]</p> + +<p><a name="15"></a></p> + +<h2>LIGHTON'S IMMERSION ILLUMINATOR</h2> + +<p>The following extremely simple plan for an immersion illuminator +was first brought to the notice of microscopists a few years ago, +and, in the absence of the inventor, was kindly described by Prof. +Albert McCalla, at the meeting of the American Society of +Microscopists, at Columbus, O. It consists of a small disk of +silvered plate glass, c, about one-eighth of an inch thick, which +is cemented by glycerine or some homogeneous immersion medium to +the under surface of the glass-slide, s. Let r represent the +silvered surface of the glass disk, b, the immersion objective, f, +the thin glass cover. It will be easily seen that the ray of light, +h, from the mirror or condenser above the stage will enter the +slide and thence be refracted to the silvered surface of the +illuminator, r, whence it is reflected at a corresponding angle to +the object in the focus of the objective. A shield to prevent +unnecessary light from entering the objective can be made of any +material at hand, by taking a strip one inch long and three-fourths +of an inch wide and turning up one end. A hole not more than +three-sixteenths of an inch in diameter should be made at the +angle. The shield should be placed on the upper surface of the +slide, so that the hole will cover the point where the light from +the mirror enters the glass. With this illuminator Möller's +balsam test-plate is resolved with ease, with suitable objectives. +Diatoms mounted dry are shown in a manner far surpassing that by +the usual arrangement of mirror, particularly with large angle dry +objectives.</p> + +<p>Ottumwa, Ia.</p> + +<p>WM. LIGHTON.</p> + +<p class="ctr"><img src="images/12d.png" alt= +"LIGHTON'S ILLUMINATOR."></p> + +<p class="ctr">LIGHTON'S ILLUMINATOR.</p> + +<hr> +<p><a name="16"></a></p> + +<h2>FOUCAULT'S PENDULUM EXPERIMENTS.</h2> + +<h3>By RICHARD A. PROCTOR.</h3> + +<p>Science owes to M. Foucault the suggestion that the motions of a +pendulum so suspended as to be free to swing in any vertical plane +might be made to give ocular demonstration of the earth's rotation. +The principle of proof may be easily exhibited, though, like nearly +all of the evidences of the earth's rotation, the complete theory +of the matter can only be mastered by the aid of mathematical +researches of considerable complexity. Suppose A B (Fig. 1) to be a +straight rod in a horizontal position bearing the free pendulum C D +suspended in some such manner as is indicated at C; and suppose the +pendulum to be set swinging in the direction of the length of the +rod A B, so that the bob D remains throughout the oscillations +vertically under the rod A B. Now, if A B be shifted in the manner +indicated by the arrows, its horizontality being preserved, it will +be found that the pendulum does not partake in this motion. Thus, +if the direction of A B was north and south at first, so that the +pendulum was set swinging in a north and south direction, it will +be found that, the pendulum will still swing in that direction, +even though the rod be made to take up an east and west +position.</p> + +<p class="ctr"><img src="images/13a.png" alt= +"Fig. 1."></p> + +<p class="ctr">Fig. 1.</p> + +<p>Nor will it matter if we suppose B (say) fixed and the rod +shifted by moving the end A horizontally round B. Further, as this +is true whatever the length of the rod, it is clear that the same +fixity of the plane of swing will be observed if the rod be shifted +horizontally as though forming part of a radial line from a point E +in its length. In these cases the plane of the pendulum's swing +will indeed be shifted <i>bodily</i>, but the direction of swing +will still continue to be from north to south.</p> + +<p>Now, let P O P' represent the polar axis of the earth; a b a +horizontal rod at the pole bearing a pendulum, as in Fig. 1. It is +clear that if the earth is rotating about P O P' in the direction +shown by the arrow, the rod a b is being shifted round, precisely +as in the case first considered. The swinging pendulum below it +will not partake in its motion; and thus, through whatever arc the +earth rotates from west to east, through the same arc will the +plane of swing of the pendulum appear to travel from east to west +under a b.</p> + +<p>But we cannot set up a pendulum to swing at the pole of the +earth. Let us inquire, then, whether the experiment ought to have +similar results if carried out elsewhere.</p> + +<p>Suppose A B to be our pendulum-bearing rod, placed (for +convenience of description merely) in a north and south position. +Then it is clear that A B produced meets the polar axis produced +(in E, suppose), and when, owing to the earth's rotation, the rod +has been carried to the position A' B', it still passes through the +point E. Hence it has shifted through the angle A E A', a motion +which corresponds to the case of the motion of A B (in Fig. 1) +about the point E,[1] and the plane of the pendulum's swing will +therefore show a displacement equal to the angle A E A'. It will be +at once seen that for a given arc of rotation the displacement is +smaller in this case than in the former, since the angle A E A' is +obviously less than the angle A K A'.[2] In our latitude a free +pendulum should seem to shift through one degree in about five +minutes.</p> + +<p>[Footnote 1: In reality A E moves to the position A' E over the +surface of a cone having E P' as axis, and E as vertex; but for any +small part of its motion, the effect is the same as though it +traveled in a plane through E, touching this cone; and the sum of +the effects should clearly be proportioned to the sum of the +angular displacements.]</p> + +<p>[Footnote 2: In fact, the former angle is less than the latter, +in the same proportion that A K is less than A E, or in the +proportion of the sine of the angle A E P, which is obviously the +same as the sine of the latitude.]</p> + +<p>It is obvious that a great deal depends on the mode of +suspension. What is needed is that the pendulum should be as little +affected as possible by its connection with the rotating earth. It +will surprise many, perhaps, to learn that in Foucault's original +mode of suspension the upper end of the wire bearing the pendulum +bob was fastened to a metal plate by means of a screw. It might be +supposed that the torsion of the wire would appreciably affect the +result. In reality, however, the torsion was very small.</p> + +<p class="ctr"><img src="images/13b.png" alt= +"Fig. 2."></p> + +<p class="ctr">Fig. 2.</p> + +<p>Still, other modes of suspension are obviously suggested by the +requirements of the problem. Hansen made use of the mode of +suspension exhibited in Fig. 3. Mr. Worms, in a series of +experiments carried out at King's College, London, adopted a +somewhat similar arrangement, but in place of the hemispherical +segment he employed a conoid, as shown in Fig. 4, and a socket was +provided in which the conoid could work freely. From some +experiments I made myself a score of years ago, I am inclined to +prefer a plane surface for the conoid to work upon. Care must be +taken that the first swing of the pendulum may take place truly in +one plane. The mode of liberation is also a matter of +importance.</p> + +<p class="ctr"><img src="images/13c.png" alt="Fig.3."></p> + +<p class="ctr">Fig.3.</p> + +<p>Many interesting experiments have been made upon the motions of +a free pendulum, regarded as a proof of the earth's rotation, and +when carefully conducted, the experiments have never failed to +afford the most satisfactory results. Space, however, will only +permit me to dwell on a single series of experiments. I select +those made by Mr. Worms in the Hall of King's College, London, in +the year 1859:</p> + +<p>"The bob was a truly turned ball of brass weighing 40 lb.; the +suspending medium was a thick steel wire; the length of the +pendulum was 17 feet 9 inches. The amplitude of the first +oscillation was 6° 42', and during the time of the +experiment--about half an hour--the arcs were not much diminished. +As I had to demonstrate to a large number of spectators, I +encountered considerable difficulty," says Mr. Worms, "in rendering +the small deviations of the plane of oscillation visible to all. I +accomplished it in three different ways." These he proceeds to +describe. He had first a set of small cones set up, which were +successively knocked down as the change in the plane of the +pendulum slowly brought the pointer under the bob to bear on cone +after cone. Secondly, a small cannon was so placed that the first +touch of the pendulum pointer against a platinum wire across the +touch-hole completed a galvanic circuit, and so fired the cannon. +Lastly, a candle was placed so as to throw the shadow of the +pendulum bob upon a ground-glass screen, and so to exhibit the +gradual change of the plane of swing.</p> + +<p>The results accorded most satisfactorily with the deductions +from the theory of the earth's rotation.</p> + +<p class="ctr"><img src="images/13d.png" alt="Fig.4."></p> + +<p class="ctr">Fig.4.</p> + +<hr> +<p><a name="19"></a></p> + +<h2>A NEW LUNARIAN.</h2> + +<h3>By Prof. C. W. MACCORD, Sc.D.</h3> + +<p>The construction of apparatus for illustrating the motions of +the heavenly bodies has often occupied the attention of both +mathematicians and mechanicians, who have produced many very +ingenious, and in some cases very complicated, combinations. These +may be divided into two classes; the object of the first being to +represent <i>exactly</i> what occurs--to reproduce the precise +movements of the various bodies represented in their true +proportions and relations to each other, in respect to distances, +magnitudes, times, and phases. When the absolute complexity of the +movements of the bodies composing the solar system is considered, +it is not so much a matter of wonder that a planetarium which shall +thus imitate them is a very delicate and complicated machine as +that it should lie within the limits of human ingenuity.</p> + +<p>In the second class, the object is to show the nature and the +causes of specific phenomena, without regard to others perhaps, and +without necessarily paying attention to exact proportions of +distances and dimensions. Indeed, it is often the case that the +illustration is made clearer by exaggerating some of these and +reducing others; thus, for example, the causes of the variation in +the lengths of the days and nights, and of the changes in the +seasons, can be exhibited to much better advantage by an apparatus +in which the diameter of the sun and its distance from the earth +are enormously reduced than they possibly could be were they of +their proper proportionate magnitudes; nor is the presence of any +other planet, or the attendance of a satellite, at all necessary or +even desirable for the purpose named.</p> + +<p>It is apparent that machines of this class can be made much more +simple than those of the first, while at the same time it may +safely be asserted that for educational purposes they are far more +useful.</p> + +<p>In both classes, the action involves the use of some sort of +epicyclic train, since the motions to be explained are both orbital +and axial. The planetary body is carried round by a train-arm, and +its rotation about its axis is usually given it by a train of +gearing, the inner or central wheel of which is stationary, being +fastened to the fixed frame supporting the whole.</p> + +<p class="ctr"><a href="images/13e.png"><img src= +"images/13e_th.jpg" alt="AN IMPROVED LUNARIAN."></a></p> + +<p class="ctr">AN IMPROVED LUNARIAN.</p> + +<p>The lunarian which we herewith present belongs to the second of +the classes above named; in its construction an attempt has been +made to show by as simple means and in as clear a manner as +possible the nature of the following phenomena, viz.:</p> + +<p>1. Apogee and perigee.</p> + +<p>2. The moon's phases.</p> + +<p>3. The rotation on her axis, by reason of which she always +presents nearly the same face to the earth.</p> + +<p>4. The inclination of her axis to the plane of her orbit, and +her consequent libration in latitude.</p> + +<p>5. Her varying angular velocity, and consequent libration in +longitude.</p> + +<p>The mechanism consists of a train-arm, T, which turns upon the +vertical pivot, P, fixed in the stand. In this arm, T, are the +bearings of two cranks, B and C. equal in length to each other and +to a third crank, A, which is stationary, being fixed to the pivot, +P, by a pin, p. To the crank-pin of A is secured a reverted arm, +A', which supports the earth, E, and keeps it also stationary. The +three cranks are connected by the rod, R, like the parallel rod of +a locomotive: to which is fastened by a steady-pin, o, the bevel +wheel, D, concentric with the crank-pin, b. The head of this +crank-pin is first made spherical, then faced off at an angle with +the axis of b, and in the sloping face is firmly fixed the long +screw, S, forming the support for the moon, M, which is caused to +rotate about the axis of S, by means of the wheel, F, equal to and +engaging with D. The upper end of S projects slightly through a +perforation in the moon, and to it the hemispherical black shell or +cap, G, is fixed by the screw, K; this cap represents the +unilluminated part of the moon, and since G, s, b, and B, are in +effect but one piece, the cap moves precisely as the crank +does.</p> + +<p>Now as the train-arm, T, is carried round, the cranks, B and C, +will turn in their bearings; but by their connection with A, they +are compelled to remain always parallel to themselves, and thus the +axis of the moon receives a motion of translation. But since during +this action the wheel D turns relatively to the pin b, the moon +evidently rotates about its axis with an angular velocity precisely +equal to that of its orbital motion.</p> + +<p>The black shell however has the motion of translation only, and +thus exhibits the phases of the moon, on the supposition that the +source of light is infinitely remote and the rays come always in +the same direction, which is not strictly true, of course; but the +reasons of the varying appearance are as clearly shown as if it +were absolutely exact. The same may be said in regard to the +phenomena of libration; the inclination of the moon's axis to the +plane of her orbit is really small, but is purposely exaggerated in +this apparatus in order to make the results apparent; in the +position represented, it is quite obvious that an observer upon the +earth can see a little past one pole, and cannot quite see the +other, as well as that this condition will be reversed after half a +revolution.</p> + +<p>The action in reference to the phases is clearly shown in the +small diagram on the right. The one on the left illustrates the +manner in which the libration in longitude is made apparent. It +will be noted that the center of M is not directly over the axis of +the bearing of the crank, B, so that after half a revolution the +moon will be farther from the earth than she is here shown. Her +orbit here is circular, whereas, in fact, it is an ellipse; but the +earth not being in the center, her angular velocity in relation to +the earth is variable, the result of which is that, when she is +near her quadrature, the actual force presented to the earth is +slightly different from that presented when in conjunction or +opposition.</p> + +<p>Thus these various peculiarities of the motion of our satellite +are exhibited by comparatively simple means--the number of moving +parts being, it is believed, as small as it can be made; and the +substitution of a crank motion for the usual train of wheels, we +think, is a new device.</p> + +<hr> +<p><a name="25"></a></p> + +<h2>THE UPRIGHT ATTITUDE OF MANKIND.</h2> + +<p>Every one must have heard or have read of the supposed perfect +adaptation of the human frame to bipedal locomotion and to an +upright attitude, as well as the advantages which we gain by this +erect position. We are told, and with perfect truth, that in man +the occipital foramen--the aperture through which the brain is +connected with the spinal cord--is so placed that the head is +nearly in equilibrium when he stands upright. In other mammalia +this aperture lies further back, and takes a more oblique +direction, so that the head is thrown forward, and requires to be +upheld partly by muscular effort and partly by the ligamentum +nuchæ, popularly known in cattle as the "pax-wax."</p> + +<p>Again, the relative lengths of the bones of the hinder +extremities in man form an obstacle to his walking on all-fours. If +we keep the legs straight we may touch the ground in front of our +feet with the tips of the fingers, but we cannot place the palms of +the hands upon the ground and use them to support any part of our +weight in walking. Not a few other points of a similar tendency +have been so often enlarged upon, in works of a teleological +character, that there can be no need even to specify them at +present.</p> + +<p>But till lately it has never been asked, "Is man's adaptation to +an upright posture perfect?" and "Is this posture attended with no +drawbacks?" These questions have been raised by Dr. S. V. Clevenger +in a lecture delivered before the Chicago University Club, on April +18, 1882, and recently published in the <i>American Naturalist</i>. +This lecture, we may add, cost the speaker the chair of Comparative +Anatomy and Physiology at the Chicago University!</p> + +<p>Dr. Clevenger first discusses the position of the valves in the +veins. The teleologists have long told us that the valves in the +veins of the arms and legs assist in the return of blood to the +heart against gravitation. But what earthly use has a man for +valves in the intercostal veins which carry blood almost +horizontally backward to the azygos veins? When recumbent, these +valves are an actual obstacle to the free flow of the blood. The +inferior thyroid veins which drop their blood into the innominate +are obstructed by valves at their junction. Two pairs of valves are +situate in the external jugular, and another pair in the internal +jugular, but they do not prevent regurgitation of blood upward.</p> + +<p>An anomaly exists in the absence of valves from parts where they +are most needed, such as the venæ cavæ, the spinal, +iliac, hæmorrhoidal, and portal veins.</p> + +<p>But if we place man upon all-fours these anomalies disappear, +and a law is found regulating the presence or absence of valves, +and, according to Dr. Clevenger, it is applicable to all quadrupeds +and to the so-called Quadrumana. Veins flowing toward the back, +i.e., against gravitation in the all-fours posture--are fitted with +valves; those flowing in other directions are without. For the few +exceptions a very feasible explanation is given.</p> + +<p>Valves in the hæmorrhoidal veins would be useless to +quadrupeds; but to man, in his upright position, they would be very +valuable. "To their absence in man many a life has been and will be +sacrificed, to say nothing of the discomfort and distress +occasioned by the engorgement known as piles, which the presence of +valves in their veins would obviate."</p> + +<p>A noticeable departure from the rule obtaining in the vascular +system of mammalia also occurs to the exposed situation of the +femoral artery in man. The arteries lie deeper than the veins, or +are otherwise protected, for the purpose--as a teleologist would +say--of preventing serious loss of blood from superficial cuts. +Translating this view into evolutionary language, it appears that +only animals with deeply placed arteries can survive and transmit +their structural peculiarities to their offspring. The ordinary +abrasions to which all animals are exposed, not to mention their +onslaughts upon each other, would quickly kill off species with +superficially placed arteries. But when man assumed the upright +posture the femoral artery, which in the quadrupedal position is +placed out of reach on the inner part of the thigh, became exposed. +Were not this defect greatly compensated by man's ability to +protect this part in ways not open to brutes, he, too, might have +become extinct. As it is, this exposure of so large an artery is a +fruitful cause of trouble and death.</p> + +<p>We may here mention some other disadvantages of the upright +position which Dr. Clevenger has omitted. Foremost comes the +liability to fall due to an erect posture supported upon two feet +only. Four-footed animals in their natural haunts are little liable +to fall; if one foot slips or fails to find hold, the other three +are available. If a fall does occur on level ground, there is very +little danger to any mammal nearly approaching man in bulk and +weight. Their vital parts, especially the heart and the head, are +ordinarily so near the ground that to them the shock is +comparatively slight. To human beings the effects of a fall on +smooth, level ground are often serious, or even deadly. We need +merely call to mind the case of the illustrious physicist whom we +have so recently and suddenly lost.</p> + +<p>The upright attitude involves a further sourge of danger. In few +parts (if any) of the body is a blow more fatal than over what is +popularly called the "pit of the stomach." In the quadruped this +part is little exposed either to accidental or intentional +injuries. In man it is quite open to both. A blow, a kick, a fall +among stones, etc., may thus easily prove fatal.</p> + +<p>Another point is the exposure and prominence of the generative +organs, which in most other animals are well protected. Leaving +danger out of the question, it may be asked whether we have not +here the origin of clothing? The assumption of the upright posture +may have made primitive man aware of his nakedness.</p> + +<p>Returning to the illustrations furnished by Dr. Clevenger, we +are reminded that another disadvantage which occurs from the +upright position of man is his greater liability to inguinal +hernia. In quadrupeds the main weight of the abdominal viscera is +supported by the ribs and by strong pectoral and abdominal muscles. +The weakest part of the latter group of muscles is in the region of +Poupart's ligament, above the groin. Inguinal hernia is rare in +other vertebrates because this weak part is relieved by the +pressure of the viscera. In man the pelvis receives almost the +entire load of the intestines, and hence Art is called in to +compensate the deficiencies of nature, and an immense number of +trusses have to be manufactured and used. It is calculated that 20 +per cent. of the human family suffer in this way. Strangulated +hernia frequently causes death. The liability to femoral hernia is +in like manner increased by the upright position.</p> + +<p>Now, if man has always been erect from his creation--or, if that +term be disliked, from his origin--we have evidently nothing to +hope from the future in the way of an amendment of this and other +defects. But if we have sprung from a quadrupedal animal, and have +by degrees adopted an upright position, to which we are as yet +imperfectly adapted, the muscular tissues of the abdomen will +doubtless in the lapse of ages become strengthened to meet the +demand made upon them, so that the liability to rupture will +decrease. In like manner the other defects above enumerated may +gradually be rendered less serious.</p> + +<p>A most important point remains; the peritoneal ligaments of the +uterus fully subserve suspensory functions. The anterior, +posterior, and lateral ligaments are mainly concerned in preventing +the gravid uterus, in quadrupeds, from pitching too far forward +toward the diaphragm. The round ligaments are utterly unmeaning in +the human female, but in the lower animals they serve the same +purpose as the other ligaments. Prolapsus uteri, from the erect +position and the absence of supports adapted to the position, is +thus rendered common, destroying the health and happiness of +multitudes.</p> + +<p>As a simple deduction from mechanical laws, it would readily +follow that any animal or race of men which had for the longest +time maintained an erect position would have straighter abdomens, +wider pelvic brims with contracted pelvic outlets, and that the +weight of the spinal column would force the sacrum lower down. +This, generally speaking, we find to be the case. In quadrupeds the +box-shaped pelvis, which admits of easy parturition, is prevalent. +Where the position of the animal is such as to throw the weight of +the viscera into the pelvis, the brim necessarily widens, these +weighty organs sink lower, and the beads of the thigh-bones acting +as fulcra permit the crest of the ilium to be carried outward, +while the lower part of the pelvis is at the same time +contracted.</p> + +<p>In the innominate bones of a young child the box-shape exists, +while its prominent abdomen resembles that of the gorilla. The +gibbon exhibits this iliac expansion through the sitting posture +which developed his ischial callosities. Similarly iliac expansion +occurs in the chimpanzee. The megatherium had wide iliacal +expansions due to its semi-erect habits; but as its weight was in +great part supported by the huge tail, and as the fermora rested in +acetabula placed far forward, the leverage necessary to contract +the lower portion of the pelvis was absent.</p> + +<p>Prof. Weber, of Bonn, quoted in Karl Vogt's "Vorlesungen ueber +den Mensohen," distinguishes four chief forms of the pelvis in +mankind--the oval in Aryans, the round among the Red Indians, the +square in the Mongols, and the wedge-shaped in the Negro. Examining +this question mechanically it would seem that the longer a race had +remained in an upright position the lower is the sacrum, and the +greater is the tendency to approximate to the larger lateral +diameter of the European female. The front to back diameter of the +ape's pelvis is usually greater than the measurement from side to +side. A similar condition affords the cuneiform, from which it may +be inferred that the erect position in the Negro has not been +maintained so long as in the Mongol, whose pelvis has assumed the +quadrilateral shape owing to persistence of spinal axis weight for +a greater time. This pressure has finally culminated in forcing the +sacrum of the European nearer the pubes, with consequent lateral +expansion and contraction of the diameter from front to back. From +the marsupials to the lemurs the box-shaped pelvis remains. With +the wedge-shape occasioned in the lowest human types there occurs a +further remarkable phenomenon in the increased size of the foetal +head accompanying the contraction of the pelvic outlet. While the +marsupial head is about one-sixth the size of the narrowest part of +the bony parturient canal, the moment we pass to erect animals the +greater relative increase is there seen in cranial size, with a +coexisting decrease in the area of the outlet. This altered +condition of things has caused the death of millions of otherwise +perfectly healthy and well-formed human mothers and children. The +palæontologist might tell us if some such case of ischial +approximation by natural mechanical causes has not caused the +probable extinction of whole genera of vertebrates. "If we are to +believe that for our original sin the pangs and labor of childbirth +were increased, and if we also believe in the disproportionate +contraction of the pelvic space being an efficient cause of the +same difficulties of parturition, the logical inference is that +man's original sin consisted in his getting upon his hind +legs."</p> + +<p>This subject is not without direct applications. Accoucheurs +cause their patients to assume what is called the knee-chest +position, a prone one, for the purpose of restoring the uterus to +something near a natural position. Brown-Sequard recommends, in +myelitis, or spinal congestion, drawing away the blood from the +spine by placing the patient on his abdomen or side, with hands and +feet somewhat hanging down. The liability to <i>spina bifida</i> is +greatest in the human infant, through the stress thrown on the +spine. The easy parturition in the lower human races is due to the +discrepancy between cranial and pelvic sizes not having been as yet +reached by those races. The Sandwich Island mother has a difficult +delivery only when her child is half white, and has consequently a +longer head than the unmixed native strain.</p> + +<p>At present the world goes on in its blindness, apparently +satisfied that everything is all right because its exists, ignorant +of the evil consequences of apparently beneficial pecularities, +vaunting man's erectness and its advantages, while ignoring the +disadvantages.</p> + +<p>The observation that the lower the animal the more prolific (not +universally true!) would warrant the belief that the higher the +animal the more difficulties encompass its propagation and +development. The cranio-pelvic difficulty may perhaps settle the +Malthusian question as far as the higher races of men are concerned +by their extinction.</p> + +<p>[If the facts brought forward by Dr. Clevenger cannot be +controverted, they seem to prove that man must have originated by +gradual development from a four-footed being. Had he been created +an erect, bipedal animal, as we find him, his structure would have +been not in partial, but in perfect, adaptation to the conditions +of that attitude. That some of the peculiarities of his structure +are better in harmony with a horizontal than a vertical position of +the spinal column, is perhaps the strongest argument against the +theory of direct creation and the radical <i>toto coelo</i> +distinction between man and beast that has yet been advanced. We +cannot at the moment lay our hands upon any thorough and +trustworthy account of the valves in the veins of the sloth: as +that animal spends its life hanging, back downward, the structure +of the veins would be interesting in this connection.--ED. J. +S.]--<i>Journal of Science</i>.</p> + +<hr> +<p><a name="26"></a></p> + +<h2>OUR ENEMIES, THE MICROBES.</h2> + +<p>We have seen the microbes, as our servants[1], often performing, +unbeknown to us, the work of purifying and regenerating the soil +and atmosphere. Let us now examine our enemies, for they are +numerous. Everywhere frequent--in the air, in the earth, in the +water--they only await an occasion to introduce themselves into our +body in order to engage in a contest for existence with the cells +that make up our tissues; and, often victorious, they cause death +with fearful rapidity. When we have named charbon, +septicæmia, diphtheria, typhoid fever, pork measles, etc., we +shall have indicated the serious affections that microbes are +capable of engendering in the animal organism.</p> + +<p>[Footnote 1: SUPPLEMENT, No. 446, page 7125.]</p> + +<p>We call those diseases "parasitic" that are occasioned by the +introduction of a living organism into the bodies of animals. +Although a knowledge of such diseases is easy where it concerns +parasites such as acari and worms, it becomes very difficult when +it is a question of diseases that are caused by the +Bacteriaceæ. In fact, the germs of these plants exist in the +air in large quantities, as is shown by the analysis of pure air by +a sunbeam, and we are obliged to take minute precautions to prevent +then from invading organic substances. If, then, during an autopsy +of an individual or animal, a microscopic examination reveals the +presence of microbes, we cannot affirm that the latter were the +cause of the affection that it is desired to study, since they +might have introduced themselves during the manipulation, and by +reason of their rapid vegetation have invaded the tissues of the +dead animal in a very short time. The presumption exists, +nevertheless, that when the same form of bacteria is present in the +same tissue with the same affection, it is connected with the +disease. This was what Davaine was the first to show with regard to +<i>Bacillus anthracis</i>, which causes charbon. He, in 1850, +having examined the blood of an animal that had died of this +disease, found therein amid the globules (Fig. 1), small, +immovable, very narrow rods of a length double that of the blood +corpuscles. It was not till 1863 that he suspected the active role +of these organisms in the charbon malady, and endeavored to +demonstrate it by experiments in inoculation. Is the presence of +these little rods in the blood of an animal that has died of +charbon sufficient of itself to demonstrate the parasitic nature of +the affection? No; in order that the demonstration shall be +complete, the bacteria must be isolated, cultivated in a state of +purity in proper liquids, and then be used to inoculate animals +with. If the latter die with all the symptoms of charbon, the +demonstration will be complete. Davaine did, indeed, perform some +experiments in inoculation that were successful, but his results +were contradicted by the experiments of Messrs. Jaillard and +Leplat, and those of Mr. Bert concerning the toxic influence of +oxygen at high tension upon microbes. As Davaine was unable to +explain the contradiction between his results and those of Messrs. +Jaillard, Leplat, and Bert, minds were not as yet convinced, +notwithstanding the support that his ideas received from Mr. Koch's +researches.</p> + +<p>In 1877 Mr. Pasteur took up Davaine's experiments, and confirmed +his affirmations step by step by employing the method of culture +that he had used with such success in his studies upon +fermentation. He isolated Davaine's bacterium by cultivating it in +a decoction of beer yeast that had been previously sterilized (Fig. +2); and after from ten to twenty cultures, he found that a portion +of the liquid containing a few bacteria, when used for inoculating +a rabbit, quickly caused the latter to die of charbon, while the +same liquid, when filtered through plaster or porcelain, became +harmless.</p> + +<p>Davaine's bacterium develops exclusively in the blood, and is +never found at any depth in the tissues. This is due to the fact +that the alga, having need of oxygen in order to live, borrows its +flow from the blood, and thus extracts from the globules that which +they should have carried to the tissue. The animal therefore dies +asphyxiated. It is on account of the absence of oxygen in the blood +that the latter assumes the blackish-brown color that characterizes +the malady, and that has given its name of <i>charbon</i> +(coal).</p> + +<p>The parasitic nature of charbon was therefore absolutely +demonstrated, first, by the constant presence of <i>Bacillus +anthracis</i> in the blood of anthracoid animals, and second, by +the pure culture of the parasite and the inoculation of animals +with charbon by means of it.</p> + +<p>Davaine began the demonstration in 1863, and Pasteur finished it +in 1877. These facts are now incontestable; yet, to show how slowly +truth is propagated, even in these days of telegraphs and +telephones, there might have been read a few months ago, in an +interesting article on microbes, by Dr. Fol, a distinguished +savant, the statement that charbon and tuberculosis were discovered +by Dr. Koch!</p> + +<p>New parasitic affections, whose existence was suspected, were +soon discovered and scientifically demonstrated, such, for example, +as septicæmia, or the putrefaction which occurs in living +animals, which in ambulances causes so fearful havoc among the +wounded, and which proceeds from <i>Bacillus septicus</i>. This +parasite exhibits itself under the form of little articulated rods +that live isolated from oxygen in the mass of the tissues, and +disorganize the latter in disengaging a large quantity of putrid +gas. Other parasites of this class are the <i>micrococcus</i> of +chicken cholera (Fig. 3), the <i>micrococcus</i> of hog measles, +and the <i>Spirochoete Obermeieri</i> of recurrent fever, +discovered by Obermeier (Fig. 5).</p> + +<p>Besides these, there are a certain number of maladies that seem +as if they must be due to the Bacteriaceæ, although a +demonstration of the fact by the method of cultures and inoculation +has not as yet been attempted. Among such, we may cite typhoid +fever, diphtheria, murrain, tuberculosis (Fig. 4), malarial fever +(Fig. 6), etc.</p> + +<p>As may be seen, the list is already a long one, and it tends +every day to still further increase. All the progress that has been +made in so few years in our knowledge of contagious or epidemic +diseases is due exclusively to M. Pasteur and the scientific method +that he introduced through his remarkable labors on fermentation. +Now that we know our most formidable enemies, how shall we defend +ourselves against them?</p> + +<p>As we have seen, bacteria exist everywhere, mixed with the dust +that interferes with the transparency of the air and covers all +objects; and they are likewise found in water.</p> + +<p>Under normal conditions, our body is closed to these organisms +through the epidermis and epithelium, and, as has been shown by Mr. +Pasteur, no bacteria are found in the blood and tissues of living +animals. But let a rupture or wound occur, and bacteria will enter +the body, and, when once the enemy is in place, it will be too +late. One sole chance of safety remains to us, and that is that in +the warfare that it is raging against our tissues the enemy may +succumb. M. Pasteur has shown that the blood corpsucles sometimes +engage in the contest against bacterides and come off victorious. +In fact, chickens are proof against poisoning by charbon, because, +owing to the high temperature of their blood, the bacterides are +unable to extract oxygen from the corpuscles thereof. But, if the +chickens be chilled, the conditions are changed, and they will die +of charbon just as do cattle and sheep; but, as the result of the +contest cannot always be foreseen, it is necessary at any cost to +prevent bacterides from entering the body.</p> + +<p class="ctr"><img src="images/15a.png" alt=""></p> + +<p class="ctr">I. Bacteria of charbon (<i>Bacillus antracis</i>.) +II. The<br> +same cultivated in yeast. III. The <i>Micrococcus</i> of chicken +cholera.<br> +IV. The <i>Bacillus</i> of tuberculosis. V. The <i>Spirillun</i> +of<br> +recurrent fever. VI. The <i>Bacillus</i> of malaria.</p> + +<p>Under ordinary circumstances a severe hygiene will suffice to +preserve us; if a wound is received it should be washed with water +mixed with antiseptics, such as phenic acid, borax, or salicylic +acid. If water is impure, it must be boiled and then aerated before +it is drunk. If the air is the vehicle of the germs of the disease, +it will have to be filtered by means of a muslin curtain kept wet +with a hygroscopic solution, glycerine for example. Finally, when, +after an epidemic, contaminated apartments are to be occupied, the +walls and floor and the clothing must be washed with antiseptic +solutions whose nature will vary according to circumstances--steam +charged with phenic acid, water mixed with a millionth part of +sulphuric acid, boric acid, ozone, chlorine, etc.</p> + +<p>These preventives only prove efficient on condition that they be +used persistently. Let our vigilance be lacking for an instant, and +the enemy will enter to work destruction, for it only requires a +spore less than a hundredth of a millimeter in diameter to produce +the most serious affections.</p> + +<p>Fortunately, and it is again to Mr. Pasteur that we owe these +wonderful discoveries, the parasitic microbes themselves, which sow +sickness and death, may, through proper culture, become true +vaccine viri that are capable of preserving the organism against +any future attack of the disease that they were capable of +producing; such vaccine matters have been discovered for charbon, +chicken cholera, the measles of swine, etc.</p> + +<p>When the <i>micrococcus</i> of chicken cholera (Fig. 3.) is +cultivated, it is seen that the activity of the microbe in cultures +exposed to the air gradually diminishes. While a drop of the liquid +would, in twenty-four hours, have killed all the chickens that were +inoculated with it, its effect after two, three, or four days +considerably diminishes, and an inoculation with it produces +nothing more than a slight indisposition in the animal, and one +that is never followed by a serious accident. It is then said that +the virulence of the microbe is attenuated.</p> + +<p>The air is the agent of this transformation that gradually +renders the bacteria benign, for in cultures made under the same +circumstances as the preceding, but with the absence of air, the +activity of these algæ is preserved for days or weeks, and +they will then cause death just as surely as they would have done +at the end of one day.</p> + +<p>What is remarkable is that animals inoculated with the +attenuated <i>micrococcus</i> become for a varying length of time +refractory to the action of the most formidable parasites of this +kind. Mr. Pasteur has discovered two such vaccine viri--one for +chicken cholera and the other for charbon. His results have not +been accepted without a struggle, and it required nothing less than +public experiment in vaccination, both in France and abroad, to +convince the incredulous. There are still people at the present +time who assert that Mr. Pasteur's process of vaccination has not a +great practical range! And yet, here we have the results; more than +400,000 animals have been vaccinated since 1881, and it has been +found that the mortality is ten times less in these than in those +that have not been vaccinated!</p> + +<p>An impetus has now been given, and we can look to the future +with confidence, for, if our enemies are numerous, the use of a +severe hygiene and preventive vaccination will permit us to +gradually free humanity from the terrible scourges that sap the +sources of fortune and life.--<i>Science et Nature</i>.</p> + +<hr> +<p><a name="21"></a></p> + +<h2>THE WINE FLY.</h2> + +<p>At the last meeting of the New York Microscopical Society, a +paper was read by Dr. Samuel Lockwood, secretary of the New Jersey +State Microscopical Society. His subject was the Wine Fly, +<i>Drosophila ampelophila</i>. The paper was a contribution to the +life-history of this minute insect. He had given in part three +years to its study, beginning in September, 1881, when nothing +whatever of its life-history seemed to have been known. In October +the flies attacked his Concords. He found upon a grape which he was +inspecting with a pocket-lens an extremely small white egg; but +lost it. The grapes when brought on the table were infested by the +flies, which proved to be the above mentioned species. When driven +from the grapes they would fly to the window, where he captured two +of them These were placed in a jar with a grape for food. In two +days he found one egg on the outer skin of the grape. The laying +was kept up for four or five days, until there were about thirty, +some on the outside of the grape and some at an opening where the +two flies had fed. The egg had a pair of curious suspenders near +the end where the mouth of the larva would develop. These +suspenders were attached at their ends to the grape, but where the +egg was laid in the soft part of the fruit the suspenders were +spread out at the surface; thus the larva would emerge clean from +the shell. The egg was 0.5 mm. in length, and about a fourth of +that in width. The larva when grown was at least four times as long +as the egg. As the larva burrowed in the juices of the fruit, two +quite prominent breathing tubes at the posterior end were kept in +the air. Between these cardinal tubes were several teat-like +points, much smaller, but having a similar function.</p> + +<p>The larvae appeared in five days after the eggs were laid. In +about as many more days the puparium state would be entered, and in +about six days more the fly or imago would appear. In ovipositing +the suspensors would leave the oviparous duct last. The paper +claimed that the curious shape of the egg compelled the female to +oviposit slowly, as it took time for the egg to assume its form; +hence, the eggs were not laid in strings or masses, but singly and +at considerable intervals.</p> + +<p>The flies are very hairy, especially the females. The neck and +even the eyes are very hirsute. The eyes are red, quite large and +pretty, though somewhat <i>outre</i> under the microscope, for from +between the little lenses are projecting, straight, stiff hairs. As +the insect is quite active, it must be that this fringing of the +tiny eyelets with hair does not materially obscure its vision. When +the minuteness of this singular arrangement is considered, it is +surely remarkable. This general hairiness of the female especially, +and that about the head, neck, and forward part of the thorax, +stands correlated to a beautiful structure found only in the male, +which has on the tarsus of each leg in the forward pair what the +lecturer called a sexual comb. It is a beautiful comb of a very +dark brown color, each comb having ten pointed and strong teeth. In +the nuptial embrace these combs are fixed in the hairy front of the +thorax of the female, thus becoming little grapnels.</p> + +<p>The flies love any vegetable substance in fermentation, whether +acetic or vinous. Hence it will abound about cider mills, swarm on +preserves in the pantry, and in cellars or places where wine is +being made or stored. The paper showed the tendency of the glucose +in the over-ripe grape to the vinous ferment, and that the fly +delighted in it. A singular accident showed how they loved even the +very high spirits. In making some of the mounts shown to the +society, Dr. Lockwood had left a bottle of 90 per cent. alcohol +uncorked over night. Next morning he was astonished to find his +alcohol of a beautiful amethystine color, and the cork out. +Inspection showed a number of these tiny creatures, which, when +filled with the purple juice of the grape, had smelt the alcohol in +the open bottle, and had gone in to drink. They had ignominiously +perished, and had given color to the liquid.--<i>Micro. +Journal</i>.</p> + +<hr> +<p>[NATURE.]</p> + +<p><a name="22"></a></p> + +<h2>THE "POTETOMETER," AN INSTRUMENT FOR MEASURING THE +TRANSPIRATION OF WATER BY PLANTS.</h2> + +<p>In view of the interest now attaching to recent advances in +vegetable physiology, it seems not unlikely that a description of +the instrument bearing the above name, lately published by Moll +(<i>Archives Neerlandaises</i>, t. xviii.), will serve as useful +purpose. The apparatus was designed to do away with certain sources +of error in Sachs' older form of the instrument, described in his +"Experimental Physiologie"--errors chiefly due to the continual +alteration of pressure during the progress of the experiment.</p> + +<p>As shown in the diagram, the "potetometer" consists essentially +of a glass tube, a d, open at both ends, and blown out into a bulb +near the lower end; an aperture also exists on either side of the +bulb at or about its equator. The two ends of the main tube are +governed by the stopcocks, a and d, and the greater length of the +tube is graduated. A perforated caoutchouc stopper is fitted into +one aparture of the bulb, e, and the tube, g k, fits hermetically +to the other. This latter tube is dilated into a cup at h to +receive the caoutchouc stopper, into which the end of the shoot to +be experimented upon is properly fixed.</p> + +<p>The fixing of the shoot is effected by caoutchouc and wire or +silk, as shown at i, and must be performed so that the clean-cut +end of the shoot is exactly at the level of a tube passing through +the perforated stopper, e, of the bulb; this is easily managed, and +is provided for by the bending of the tube, g h. The tube, f, +passing horizontally through the caoutchouc stopper, e, is intended +to admit bubbles of air, and so equalize the pressure and at the +same time afford a means of measuring the rapidity of the +absorption of water by the transpiring shoot. This tube (see Fig. +2, f) is a short piece of capillary glass tubing, to which is fixed +a thin sheath of copper, b', which slides on it, and supports a +small plate of polished copper, a', in such a manner that the +latter can be held vertically at a small distance from the inner +opening of the tube, and so regulate the size of the bubble of air +to be directed upward into the graduated tube, a b.</p> + +<p class="ctr"><img src="images/15b.png" alt=""></p> + +<p>The apparatus is filled by placing the lower end of the main +tube under water, closing the tubes, f and i (with caoutchouc +tubing and clips), and opening the stopcocks, a and d. Water is +then sucked in from a, and the whole apparatus carefully filled. +The cocks are then turned, and the cut end of the shoot fixed into +i, as stated; care must be taken that no air remains under the cut +end at i, and the end of the shoot must be at the level, k l. This +done, the tube, f, may then be opened.</p> + +<p>The leaves of the shoot transpire water, which is replaced +through the stem at the cut end in i from the water in the +apparatus. A bubble of air passes through the tube, f, and at once +ascends into the graduated tube, a c. The descent of the +water-level in this tube--which may conveniently be graduated to +measure cubic millimeters--enables the experimenter at once to read +off the amount of water employed in a given time.</p> + +<p>It is not necessary to dwell on obvious modifications of these +essentials, nor to speak of the slight difficulties of manipulation +(especially with the tube, f). Of course the apparatus might be +mounted in several ways; and excellent results for demonstration in +class could be obtained by arranging the whole on one of the pans +of a sensitive balance. H. MARSHALL WARD.</p> + +<p>Botanical Laboratory, Owens College.</p> + +<hr> +<p><a name="23"></a></p> + +<h2>BOLIVIAN CINCHONA FORESTS.</h2> + +<p>The great progress made in the acclimation of cinchona trees in +India, Ceylon, and elsewhere has awakened the governments of +countries where the plants are indigenous to the necessity of +conserving from reckless destruction, and replanting denuded +forests, so as to be able to keep up the supply of this valuable +product.</p> + +<p>In Bolivia, since 1878, according to the report of the +Netherlands Consul, private individuals and land owners have taken +up the question with great earnestness, and at the present time on +the banks of the Mapiri, in the department of La Paz, there are +over a million of young trees growing.</p> + +<p>New plantations have also sprung up in various other localities, +either on private ground or that owned by Government. The +competition of India and Ceylon in supplying the markets has had +also the effect of inducing more care in collecting and also of +revisiting old spots, often with the result of a rich harvest of +bark which had been left on partly denuded trunks, and the opening +up of new localities. The new shoots springing up from the old +stumps have yielded much quill bark, and the root bark of the old +stumps has also been utilized.</p> + +<p>The replanting entails very little expense. The Indian tenant on +an estate has a house and land from the owner (hacienda) of the +estate. For this he binds himself to work for two to four days a +week, at from 28 to 36 cents per day, women and children obtaining +16 to 21 cents per day. Thus the planting, weeding, etc., during +the first two years is but nominal in expense; after this period +the trees may be left to themselves.</p> + +<p>On Government land the expense is greater, as, after an +application being made, the land is put up to public auction, and +may fetch a very low or higher price according to the bidding. The +land secured, contracts are made with natives of the lower class to +clear the forest and plant cinchona. The contracts are often sublet +to Indians. The young plants are planted from five to six feet +apart, with banana trees between, on account of their rapid growth +and the shade the latter afford. From March to June, after the wet +season is over, is the best time for planting, and the contractor +keeps the plantation free from weeds and in good order for twelve +months, when it is handed over to the owner. The following is given +as the cost of the Mapiri River plantation of an area from 60 or +more miles in extent:</p> + +<pre> + Ground. $1,200 + 300,000 plants at $0.14. 42,000 + Superintendent, buildings, etc. 4,400 + Interest. 4,800 + ------- + Total. $52,400 +</pre> + +<p>Till the plants are above two years of age, they are liable to +die from drought or the attacks of ants, and during 1878 many +thousands died from these causes. At the end of the fourth year +some proprietors begin to collect the quill bark by the method of +coppicing.</p> + +<p>It is feared by some that, should this new venture be +successful, it will prove a dangerous rival to the plantations of +India, Ceylon, and Java, and lower the price of bark +considerably.--<i>Jour. Society of Arts</i>.</p> + +<hr> +<p><a name="24"></a></p> + +<h2>FERNS.</h2> + +<p><i>N. Davallioides Furcans.</i>--Among the many crested ferns in +cultivation, this, of which the annexed is an illustration, is one +of the most distinct; so different indeed it is from the type, that +it is questionable if it really is a form of it; the most essential +characteristic, that of the fructification at the extreme edge of +the lobes of the pinnæ, is altogether absent, and the whole +habit of the plant is also thoroughly distinct. It is of equally +robust growth, but its handsomely arching fronds, which are from 3 +feet to 4 feet in length, are produced in great abundance from a +central tuft or agglomeration of crowns. Its most distinct +characteristic is the furcation of the pinnæ, which are all +of the same dimensions, whether sterile or fertile; they are all +opposite and closely set along the mid-rib, whereas those of N. +davallioides are set much further apart. In the barren pinnæ +which are only situated on the lower portion of the frond, and +which generally are only few in number, the furcation is +rudimentary; in the fertile pinnæ it is twice and even three +times repeated in the extremities of the first division, becoming +more complex toward the point of the frond, where it often forms +quite a large tassel, whose weight gives the fronds quite an +elegant, arching habit. On that account this plant is valuable for +growing in baskets of large dimensions, in which it shows itself +off to good advantage, and never fails to prove attractive. +Although it produces spores freely, it is best to propagate it by +means of the young plants produced from rhizomes in the ordinary +way, on account of the extreme variations which take place among +the seedlings, a small percentage only of which are possessed of +the true character of the parent plant. Stove.--<i>The +Garden.</i></p> + +<p class="ctr"><img src="images/16a.png" alt= +"NEPHROLEPIS DAVALLIOIDES FURCANS."></p> + +<p class="ctr">NEPHROLEPIS DAVALLIOIDES FURCANS.</p> + +<p><i>N. Duffi</i>.--This pretty, neat-habited species, of which an +illustration, kindly lent us by Mr. Bull, appears in another place, +is a native of the Duke of York's Island, in the South Pacific +Ocean, and is undoubtedly one of the most interesting of the whole +genus. Its compact habit, its comparatively small dimensions, and +the bright, glossy color of its beautifully tasseled fronds render +it a most welcome addition to a group of ferns naturally rich in +decorative plants. Its curiously and irregularly pinnate fronds are +borne on slender stalks, terete toward the base, and covered with +reddish brown, downy scales, instead of being produced loosely, as +in most other Nephrolepises; these are densily crowded, and the +outcome of closely clustered crowns. They measure from 15 inches to +18 inches long, and are terminated by very handsome massive crests, +which vary in size according to the temperature in which the plant +is grown. We have at different times heard complaints of these +fronds being simply furcate, when the same plant, after being +subjected to a greater amount of heat and moisture, produced fronds +very heavily tasseled, and partaking of an elegant vase-shaped +appearance. In fact, nothing short of the moist heat of a stove +will induce it to show its characters in their best condition. The +pinnæ, which are small, of different sizes, rounded and +serrated at the edges, are produced in pairs, one overlying the +other, and, curiously enough, those on the top are the largest. The +pairs are sometimes opposite, but mostly alternate, distant toward +the base, approximate higher up, and crowded and quite overlapping +in the crested portion of the frond. This, being a thoroughly +barren kind, can only be propagated by division of the crowns, an +operation easily done at any time of the year, but most safely in +early spring and by young plants produced from the rhizomes, which, +however, are produced much more sparingly than in any other +species. It is also one of the best adapted for pot or pan culture, +its somewhat upright habit making it less suitable for baskets, +brackets, and wall covering than other species. Stove.--<i>The +Garden</i>.</p> + +<p class="ctr"><img src="images/16b.png" alt= +"NEPHROLEPIS DUFFI."></p> + +<p class="ctr">NEPHROLEPIS DUFFI.</p> + +<hr> +<h2>FORMATION OF SUGAR.</h2> + +<p>A paper on "The Formation of Sugar in the Sugar-cane" was +recently read by M. Aimé Girard before the Paris Academy of +Sciences. By comparative investigations of the amount of cane sugar +and grape sugar in different parts of the sugar-cane in the +afternoon and before sunrise, the author has found that only in the +substance of the leaves does this quantity vary, and that the +quantity of cane sugar sinks during the night to one-half, while +the quantity of reducing sugar remains almost unaltered. He finds +further that the quantity of sugar-cane in the leaves increases +with the illumination, on very bright days reaching nearly one per +cent., considerably less on dull ones, and in either case +diminishing during the night by one-half. From this the author +concludes that the formation of saccharose from glucose takes place +entirely in the leaves under the influence of sunlight, and that +the saccharose thereupon ascends the cane through the petioles, +etc., and collects there.</p> + +<hr> +<p>A catalogue, containing brief notices of many important +scientific papers heretofore published in the SUPPLEMENT, may be +had gratis at this office.</p> + +<hr> +<h2>THE SCIENTIFIC AMERICAN SUPPLEMENT.</h2> + +<h3>PUBLISHED WEEKLY.</h3> + +<p><b>Terms of Subscription, $5 a Year.</b></p> + +<p>Sent by mail, postage prepaid, to subscribers in any part of the +United States or Canada. Six dollars a year, sent, prepaid, to any +foreign country.</p> + +<p>All the back numbers of THE SUPPLEMENT, from the commencement, +January 1, 1876, can be had. Price, 10 cents each.</p> + +<p>All the back volumes of THE SUPPLEMENT can likewise be supplied. +Two volumes are issued yearly. 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