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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/11383-0.txt b/11383-0.txt new file mode 100644 index 0000000..1cb19f3 --- /dev/null +++ b/11383-0.txt @@ -0,0 +1,4249 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 11383 *** + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 531 + + + + +NEW YORK, MARCH 6, 1886 + +Scientific American Supplement. Vol. XXI, No. 531. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY AND METALLURGY.--Annatto.-Analyses of the same.--By + WM. LAWSON + + Aluminum.--By J.A. PRICE.--Iron the basis of civilization.-- + Aluminum the metal of the future.--Discovery of aluminum.--Art + of obtaining the metal.--Uses and possibilities + +II. ENGINEERING AND MECHANICS.--The Use of Iron in Fortification. + --Armor-plated casements.--The Schumann-Gruson chilled iron + cupola.--Mougin's rolled iron cupola.--With full page + of engravings + + High Speed on the Ocean + + Sibley College Lectures.--Principles and Methods of Balancing + Forces developed in Moving Bodies.--Momentum and centrifugal + force.--By CHAS.T. PORTER.--3 figures + + Compressed Air Power Schemes.--By J. STURGEON.--Several + figures + + The Berthon Collapsible Canoe.--2 engravings + + The Fiftieth Anniversary of the Opening of the First German + Steam Railroad.--With full page engraving + + Improved Coal Elevator.--With engraving + +III. TECHNOLOGY.--Steel-making Ladles.--4 figures + + Water Gas.--The relative value of water gas and other gases as + Iron-reducing Agents.--By B.H. THWAITE.--Experiments.--With + tables and 1 figure + + Japanese Rice Wine and Soja Sauce.--Method of making + +IV. ELECTRICITY, MICROSCOPY, ETC.-Apparatus for demonstrating + that Electricity develops only on the Surface of Conductors.--1 + figure + + The Colson Telephone.--3 engravings + + The Meldometer.--An apparatus for determining the melting + points of minerals + + Touch Transmission by Electricity in the Education of Deaf + Mutes.--By S. TEFFT WALKER.--With 1 figure + +V. HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By + C.F. HOLDER.--With 2 engravings + + How Plants are reproduced.--By C.E. STUART.--A paper read + before the Chemists' Assistants' Association + +VI. MISCELLANEOUS--The Origin of Meteorites.--With 1 figure + + * * * * * + + + + +THE USE OF IRON IN FORTIFICATION. + + +Roumania is thinking of protecting a portion of the artillery of the +forts surrounding her capital by metallic cupolas. But, before deciding +upon the mode of constructing these formidable and costly affairs, and +before ordering them, she has desired to ascertain their efficacy and +the respective merits of the chilled iron armor which was recently in +fashion and of rolled iron, which looks as if it were to be the fashion +hereafter. + +[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.] + +The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a turret +of rolled iron. Both of these recommend themselves by various merits, +and by remarkably ingenious arrangements, and it only remains to be seen +how they will behave under the fire of the largest pieces of artillery. + +[Illustration: FIG. 2.] + +We are far in advance of the time when cannons with smooth bore were +obliged to approach to within a very short range of a scarp in order to +open a breach, and we are far beyond that first rifled artillery which +effected so great a revolution in tactics. + +[Illustration: FIG. 3.] + +To-day we station the batteries that are to tear open a rampart at +distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch +cannon that arms them has for probable deviations, under a charge of 20 +pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16 +inches in direct fire and 8 inches in curved. + +The weight of the projectile is 88 pounds, and its remanent velocity at +the moment of impact is 1,295 feet. Under this enormous live force, the +masonry gradually crumbles, and carries along the earth of the parapet, +and opens a breach for the assaulting columns. + +[Illustration: FIG. 4--STATE OF A CUPOLA AFTER THE ACTION OF +THIRTY-SEVEN 6 IN. PROJECTILES.] + +In order to protect the masonry of the scarp, engineers first lowered +the cordon to the level of the covert-way. Under these circumstances, +the enemy, although he could no longer see it, reached it by a curved or +"plunging" shot. When, in fact, for a given distance we load a gun with +the heaviest charge that it will stand, the trajectory, AMB (Fig. 2), is +as depressed as possible, and the angles, a and a', at the start and +arrival are small, and we have a direct shot. If we raise the chase of +the piece, the projectile will describe a curve in space which would be +a perfect parabola were it not for the resistance of the air, and the +summit of such curve will rise in proportion as the angle so increases. +So long as the falling angle, a, remains less than 45°, we shall have a +curved shot. When the angle exceeds this, the shot is called "vertical." +If we preserve the same charge, the parabolic curve in rising will meet +the horizontal plane at a greater distance off. This is, as well known, +the process employed for reaching more and more distant objects. + +[Illustration: Fig. 5.--STATE OF A CAST-IRON CUPOLA AFTER THE BREAKAGE +OF A VOUSSOIR.] + +The length of a gun depends upon the maximum charge burned in it, since +the combustion must be complete when the projectile reaches the open +air. It results from this that although guns of great length are capable +of throwing projectiles with small charges, it is possible to use +shorter pieces for this purpose--such as howitzers for curved shots and +mortars for vertical ones. The curved shot finds one application in the +opening of breaches in scarp walls, despite the existence of a covering +of great thickness. If, from a point, a (Fig. 3), we wish to strike the +point, b, of a scarp, over the crest, c, of the covert-way, it will +suffice to pass a parabolic curve through these three points--the +unknown data of the problem, and the charge necessary, being +ascertained, for any given piece, from the artillery tables. In such +cases it is necessary to ascertain the velocity at the impact, since the +force of penetration depends upon the live force (mv²) of the +projectile, and the latter will not penetrate masonry unless it have +sufficient remanent velocity. Live force, however, is not the sole +factor that intervenes, for it is indispensable to consider the angle at +which the projectile strikes the wall. Modern guns, such as the Krupp 6 +inch and De Bange 6 and 8 inch, make a breach, the two former at a +falling angle of 22°, and the latter at one of 30°. It is not easy to +lower the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass of the +glacis. + +The same guns are employed for dismounting the defender's pieces, which +he covers as much as possible behind the parapet. Heavy howitzers +destroy the _materiel_, while shrapnel, falling nearly vertically, and +bursting among the men, render all operations impossible upon an open +terre-plein. + +[Illustration: FIG. 6.--STATE OF A CHILLED IRON CUPOLA BROKEN BY A 12 +INCH BALL.] + +The effect of 6 and 8 inch rifled mortars is remarkable. The Germans +have a 9 inch one that weighs 3,850 pounds, and the projectile of which +weighs 300. But French mortars in nowise cede to those of their +neighbors; Col. De Bange, for example, has constructed a 10½ inch one of +wonderful power and accuracy. + +Seeing the destructive power of these modern engines of war, it may well +be asked how many pieces the defense will be able to preserve intact for +the last period of a siege--for the very moment at which it has most +need of a few guns to hold the assailants in check and destroy the +assaulting columns. Engineers have proposed two methods of protecting +these few indispensable pieces. The first of these consists in placing +each gun under a masonry vault, which is covered with earth on all sides +except the one that contains the embrasure, this side being covered with +armor plate. + +The second consists in placing one or two guns under a metallic cupola, +the embrasures in which are as small as possible. The cannon, in a +vertical aim, revolves around the center of an aperture which may be of +very small dimensions. As regards direct aim, the carriages are +absolutely fixed to the cupola, which itself revolves around a vertical +axis. These cupolas may be struck in three different ways: (1) at right +angles, by a direct shot, and consequently with a full charge--very +dangerous blows, that necessitate a great thickness of the armor plate; +(2) obliquely, when the projectile, if the normal component of its real +velocity is not sufficient to make it penetrate, will be deflected +without doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy. + +General Brialmont says that the metal of the cupola should be able to +withstand both penetration and breakage; but these two conditions +unfortunately require opposite qualities. A metal of sufficient +ductility to withstand breakage is easily penetrated, and, conversely, +one that is hard and does not permit of penetration does not resist +shocks well. Up to the present, casehardened iron (Gruson) has appeared +to best satisfy the contradictory conditions of the problem. Upon the +tempered exterior of this, projectiles of chilled iron and cast steel +break upon striking, absorbing a part of their live force for their own +breakage. + +In 1875 Commandant Mougin performed some experiments with a chilled iron +turret established after these plans. The thickness of the metal +normally to the blows was 23½ inches, and the projectiles were of cast +steel. The trial consisted in firing two solid 12 in. navy projectiles, +46 cylindrical 6 in. ones, weighing 100 lb., and 129 solid, pointed +ones, 12 in. in diameter. The 6 inch projectiles were fired from a +distance of 3,280 feet, with a remanent velocity of 1,300 feet. The +different phases of the experiment are shown in Figs. 4, 5, and 6. The +cupola was broken; but it is to be remarked that a movable and +well-covered one would not have been placed under so disadvantageous +circumstances as the one under consideration, upon which it was easy to +superpose the blows. An endeavor was next made to substitute a tougher +metal for casehardened iron, and steel was naturally thought of. But +hammered steel broke likewise, and a mixed or compound metal was still +less successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was rolled +iron. Armor plate composed of this latter has been submitted to several +tests, which appear to show that a thickness of 18 inches will serve as +a sufficient barrier to the shots of any gun that an enemy can +conveniently bring into the field. + +[Illustration: FIG. 7.--CASEMATE OF CHILLED IRON AFTER RECEIVING +NINETY-SIX SHOTS.] + +_Armor Plated Casemates_.--Fig. 7 shows the state of a chilled iron +casemate after a vigorous firing. The system that we are about to +describe is much better, and is due to Commandant Mougin. + +[Illustration: FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.] + +The gun is placed under a vault whose generatrices are at right angles +to the line of fire (Fig. 8), and which contains a niche that traverses +the parapet. This niche is of concrete, and its walls in the vicinity of +the embrasure are protected by thick iron plate. The rectangular armor +plate of rolled iron rests against an elastic cushion of sand compactly +rammed into an iron plate caisson. The conical embrasure traverses this +cushion by means of a cast-steel piece firmly bolted to the caisson, and +applied to the armor through the intermedium of a leaden ring. +Externally, the cheeks of the embrasure and the merlons consist of +blocks of concrete held in caissons of strong iron plate. The +surrounding earthwork is of sand. For closing the embrasure, Commandant +Mougin provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected by +the sloping mass of concrete that covers the head of the casemate. A +windlass and chain give the disk the motion that brings one of its +apertures opposite the embrasure or that closes the latter. When this +portion of the disk has suffered too much from the enemy's fire, a +simple maneuver gives it a half revolution, and the second aperture is +then made use of. + +_The Schumann-Gruson Chilled Iron Cupola_.--This cupola (Fig. 9) is +dome-shaped, and thus offers but little surface to direct fire; but it +can be struck by a vertical shot, and it may be inquired whether its top +can withstand the shock of projectiles from a 10 inch rifled mortar. It +is designed for two 6 inch guns placed parallel. Its internal diameter +is 19½ feet, and the dome is 8 inches in thickness and has a radius of +16½ feet. It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of relatively +small bulk--a bad feature as regards resistance to shock. To obviate +this difficulty, the inventor partitions it internally in such a way as +to leave only sufficient space to maneuver the guns. The partitions +consist of iron plate boxes filled with concrete. The form of the dome +has one inconvenience, viz., the embrasure in it is necessarily very +oblique, and offers quite an elongated ellipse to blows, and the edges +of the bevel upon a portion of the circumference are not strong enough. +In order to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides of +the embrasure. The motion of the piece necessary to aim it vertically is +effected around this axis of rotation. The weight of the gun is balanced +by a system of counterpoises and the chains, l, and the breech +terminates in a hollow screw, f, and a nut, g, held between two +directing sectors, h. The cupola is revolved by simply acting upon the +rollers. + +[Illustration: FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.] + +_Mougin's Rolled Iron Cupola_.--The general form of this cupola (Fig. 1) +is that of a cylindrical turret. It is 12¾ feet in diameter, and rises +3¼ feet above the top of the glacis. It has an advantage over the one +just described in possessing more internal space, without having so +large a diameter; and, as the embrasures are at right angles with the +sides, the plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of strong +iron plate strengthened by angle irons. Vertical partitions under the +cheeks of the gun carriages serve as cross braces, and are connected +with each other upon the table of the hydraulic pivot around which the +entire affair revolves. This pivot terminates in a plunger that enters a +strong steel press-cylinder embedded in the masonry of the lower +concrete vault. + +The iron plate ring carries wheels and rollers, through the intermedium +of which the turret is revolved. The circular iron track over which +these move is independent of the outer armor. + +The whole is maneuvered through the action of one man upon the piston of +a very small hydraulic press. The guns are mounted upon hydraulic +carriages. The brake that limits the recoil consists of two bronze pump +chambers, a and b (Fig. 10). The former of these is 4 inches in +diameter, and its piston is connected with the gun, while the other is 8 +inches in diameter, and its piston is connected with two rows of 26 +couples of Belleville springs, d. The two cylinders communicate through +a check valve. + +When the gun is in battery, the liquid fills the chamber of the 4 inch +pump, while the piston of the 8 inch one is at the end of its stroke. A +recoil has the effect of driving in the 4 inch piston and forcing the +liquid into the other chamber, whose piston compresses the springs. At +the end of the recoil, the gunner has only to act upon the valve by +means of a hand-wheel in order to bring the gun into battery as slowly +as he desires, through the action of the springs. + +[Illustration: FIG. 10.--MOUGIN'S HYDRAULIC GUN CARRIAGE.] + +For high aiming, the gun and the movable part of its carriage are +capable of revolving around a strong pin, c, so placed that the axis of +the piece always passes very near the center of the embrasure, thus +permitting of giving the latter minimum dimensions. The chamber of the 8 +inch pump is provided with projections that slide between circular +guides, and carries the strap of a small hydraulic piston, p, that +suffices to move the entire affair in a vertical plane, the gun and +movable carriage being balanced by a counterpoise, q. + +The projectiles are hoisted to the breech of the gun by a crane. + +Between the outer armor and turret sufficient space is left for a man to +enter, in order to make repairs when necessary. + +Each of the rolled iron plates of which the turret consists weighs 19 +tons. The cupolas that we have examined in this article have been +constructed on the hypothesis than an enemy will not be able to bring +into the field guns of much greater caliber than 6 inches.--_Le Genie +Civil_. + + * * * * * + + + + +HIGH SPEED ON THE OCEAN. + + +_To the Editor of the Scientific American_: + +Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN of +Jan. 2, 1886, in regard to high speed on the ocean. + +Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the plane +of their motion, but at an angle to it, the same principle would, if +applied to a steamship, increase its speed. But let us look at the +subject from another standpoint. The quadruped has to support the weight +of his body, and propel himself forward, with the same force. If the +force be applied perpendicularly, the body is elevated, but not moved +forward. If the force is applied horizontally, the body moves forward, +but soon falls to the ground, because it is not supported. But when the +force is applied at the proper angle, the body is moved forward and at +the same time supported. Directly contrary to Capt. Giles' theory, the +greater the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and _vice versa_. This may +easily be seen by any one watching the motions of the horse, hound, +deer, rabbit, etc., when in rapid motion. The water birds and animals, +whose weight is supported by the water, do not exert the propulsive +force in a downward direction, but in a direct line with the plane of +their motion. The man who swims does not increase his motion by kicking +out at an angle, but by drawing the feet together with the legs +straight, thus using the water between them as a double inclined plane, +on which his feet and legs slide and thus increase his motion. The +weight of the steamship is already supported by the water, and all that +is required of the propeller is to push her forward. If set so as to act +in a direct line with the plane of motion, it will use all its force to +push her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. If +placed at an angle of 45° with the plane of motion, half the force will +be used in raising the ship out of the water, and only half will be left +to push her forward. + +ENOS M. RICKER. + +Park Rapids, Minn., Jan. 23, 1886. + + * * * * * + + + + +SIBLEY COLLEGE LECTURES. + +BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING. + + + + +PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING BODIES. + +BY CHAS. T. PORTER. + +INTRODUCTION. + + +On appearing for the first time before this Association, which, as I am +informed, comprises the faculty and the entire body of students of the +Sibley College of Mechanical Engineering and the Mechanic Arts, a +reminiscence of the founder of this College suggests itself to me, in +the relation of which I beg first to be indulged. + +In the years 1847-8-9 I lived in Rochester, N.Y., and formed a slight +acquaintance with Mr. Sibley, whose home was then, as it has ever since +been, in that city. Nearly twelve years afterward, in the summer of +1861, which will be remembered as the first year of our civil war, I met +Mr. Sibley again. We happened to occupy a seat together in a car from +New York to Albany. He recollected me, and we had a conversation which +made a lasting impression on my memory. I said we had a conversation. +That reminds me of a story told by my dear friend, of precious memory, +Alexander L. Holley. One summer Mr. Holley accompanied a party of +artists on an excursion to Mt. Katahdin, which, as you know, rises in +almost solitary grandeur amid the forests and lakes of Maine. He wrote, +in his inimitably happy style, an account of this excursion, which +appeared some time after in _Scribner's Monthly_, elegantly illustrated +with views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. Katahdin. +"That is," he explained, "Mr. Church painted, and I held the umbrella." + +This describes the conversation which Mr. Sibley and I had. Mr. Sibley +talked, and I listened. He was a good talker, and I flatter myself that +I rather excel as a listener. On that occasion I did my best, for I knew +whom I was listening to. I was listening to the man who combined bold +and comprehensive grasp of thought, unerring foresight and sagacity, and +energy of action and power of accomplishment, in a degree not surpassed, +if it was equaled, among men. + +Some years before, Mr. Sibley had created the Western Union Telegraph +Company. At that time telegraphy was in a very depressed state. The +country was to a considerable extent occupied by local lines, chartered +under various State laws, and operated without concert. Four rival +companies, organized under the Morse, the Bain, the House, and the +Hughes patents, competed for the business. Telegraph stock was nearly +valueless. Hiram Sibley, a man of the people, a resident of an inland +city, of only moderate fortune, alone grasped the situation. He saw that +the nature of the business, and the demands of the country, alike +required that a single organization, in which all interests should be +combined, should cover the entire land with its network, by means of +which every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this vividly, +and realized it with the most intense earnestness of conviction. With +Mr. Sibley, to be convinced was to act; and so he set about the task of +carrying this vast scheme into execution. The result is well known. By +his immense energy, the magnetic power with which he infused his own +convictions into other minds, the direct, practical way in which he set +about the work, and his indomitable perseverance, Mr. Sibley attained at +last a phenomenal success. + +But he was not then telling me anything about this. He was telling me of +the construction of the telegraph line to the Pacific Coast. Here again +Mr. Sibley had seen that which was hidden from others. This case +differed from the former one in two important respects. Then Mr. Sibley +had been dependent on the aid and co-operation of many persons; and this +he had been able to secure. Now, he could not obtain help from a human +being; but he had become able to act independently of any assistance. + +He had made a careful study of the subject, in his thoroughly practical +way, and had become convinced that such a line was feasible, and would +be remunerative. At his instance a convention of telegraph men met in +the city of New York, to consider the project. The feeling in this +convention was extremely unfavorable to it. A committee reported against +it unanimously, on three grounds--the country was destitute of timber, +the line would be destroyed by the Indians, and if constructed and +maintained, it would not pay expenses. Mr. Sibley found himself alone. +An earnest appeal which he made from the report of the committee was +received with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and two +thousand miles of its breadth by bands of savages, who of course would +destroy the line as soon as it was put up, and where repairs would be +difficult and useless, even if the other objections to it were out of +the way, struck the members of the convention as so exquisitely +ludicrous that it seemed as if they would never be done laughing about +it. If Mr. Sibley had advocated a line to the moon, they would hardly +have seen in it greater evidence of lunacy. When he could be heard, he +rose again and said: "Gentlemen, you may laugh, but if I was not so old, +I would build the line myself." Upon this, of course, they laughed +louder than ever. As they laughed, he grew mad, and shouted: "Gentlemen, +I will bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon it +scouted the project as chimerical, and no capitalist would put a dollar +in it, Hiram Sibley built the line of telegraph to San Francisco, +risking in it all he had in the world. He set about the work with his +customary energy, all obstacles vanished, and the line was completed in +an incredibly short time. And from the day it was opened, it has proved +probably the most profitable line of telegraph that has ever been +constructed. There was the practicability, and there was the demand and +the business to be done, and yet no living man could see it, or could be +made to see it, except Hiram Sibley. "And to-day," he said, with honest +pride, "to-day in New York, men to whom I went almost on my knees for +help in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one." + +"But how about the Indians?" I asked. "Why," he replied, "we never had +any trouble from the Indians. I knew we wouldn't have. Men who supposed +I was such a fool as to go about this undertaking before that was all +settled didn't know me. No Indian ever harmed that line. The Indians are +the best friends we have got. You see, we taught the Indians the Great +Spirit was in that line; and what was more, we proved it to them. It +was, by all odds, the greatest medicine they ever saw. They fairly +worshiped it. No Indian ever dared to do it harm." + +"But," he added, "there was one thing I didn't count on. The border +ruffians in Missouri are as bad as anybody ever feared the Indians might +be. They have given us so much trouble that we are now building a line +around that State, through Iowa and Nebraska. We are obliged to do it." + +This opened another phase of the subject. The telegraph line to the +Pacific had a value beyond that which could be expressed in money. It +was perhaps the strongest of all the ties which bound California so +securely to the Union, in the dark days of its struggle for existence. +The secession element in Missouri recognized the importance of the line +in this respect, and were persistent in their efforts to destroy it. We +have seen by what means their purpose was thwarted. + +I have always felt that, among the countless evidences of the ordering +of Providence by which the war for the preservation of the Union was +signalized, not the least striking was the raising up of this remarkable +man, to accomplish alone, and in the very nick of time, a work which at +once became of such national importance. + +This is the man who has crowned his useful career, and shown again his +eminently practical character and wise foresight, by the endowment of +this College, which cannot fail to be a perennial source of benefit to +the country whose interests he has done so much to promote, and which +his remarkable sagacity and energy contributed so much to preserve. + +We have an excellent rule, followed by all successful designers of +machinery, which is, to make provision for the extreme case, for the +most severe test to which, under normal conditions, and so far as +practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than the +extreme demand are not likely to give trouble. I shall apply this +principle in addressing you to-day. In what I have to say, I shall speak +directly to the youngest and least advanced minds among my auditors. If +I am successful in making an exposition of my subject which shall be +plain to them, then it is evident that I need not concern myself about +being understood by the higher class men and the professors. + +The subject to which your attention is now invited is + + +THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES. + +This is a subject with which every one who expects to be concerned with +machinery, either as designer or constructor, ought to be familiar. The +principles which underlie it are very simple, but in order to be of use, +these need to be thoroughly understood. If they have once been mastered, +made familiar, incorporated into your intellectual being, so as to be +readily and naturally applied to every case as it arises, then you +occupy a high vantage ground. In this particular, at least, you will not +go about your work uncertainly, trying first this method and then that +one, or leaving errors to be disclosed when too late to remedy them. On +the contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what you +intend. + +Moreover, when you read discussions on any branch of this subject, you +will not receive these into unprepared minds, just as apt to admit error +as truth, and possessing no test by which to distinguish the one from +the other; but you will be able to form intelligent judgments with +respect to them. You will discover at once whether or not the writers +are anchored to the sure holding ground of sound principles. + +It is to be observed that I do not speak of balancing bodies, but of +balancing forces. Forces are the realities with which, as mechanical +engineers, you will have directly to deal, all through your lives. The +present discussion is limited also to those forces which are developed +in moving bodies, or by the motion of bodies. This limitation excludes +the force of gravity, which acts on all bodies alike, whether at rest or +in motion. It is, indeed, often desirable to neutralize the effect of +gravity on machinery. The methods of doing this are, however, obvious, +and I shall not further refer to them. + +Two very different forces, or manifestations of force, are developed by +the motion of bodies. These are + + +MOMENTUM AND CENTRIFUGAL FORCE. + +The first of these forces is exerted by every moving body, whatever the +nature of the path in which it is moving, and always in the direction of +its motion. The latter force is exerted only by bodies whose path is a +circle, or a curve of some form, about a central body or point, to which +it is held, and this force is always at right angles with the direction +of motion of the body. + +Respecting momentum, I wish only to call your attention to a single +fact, which will become of importance in the course of our discussion. +Experiments on falling bodies, as well as all experience, show that the +velocity of every moving body is the product of two factors, which must +combine to produce it. Those factors are force and distance. In order to +impart motion to the body, force must act through distance. These two +factors may be combined in any proportions whatever. The velocity +imparted to the body will vary as the square root of their product. +Thus, in the case of any given body, + + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. + +This table might be continued indefinitely. The product of the force +into the distance will always vary as the square of the final velocity +imparted. To arrest a given velocity, the same force, acting through the +same distance, or the same product of force into distance, is required +that was required to impart the velocity. + +The fundamental truth which I now wish to impress upon your minds is +that in order to impart velocity to a body, to develop the energy which +is possessed by a body in motion, force must act through distance. +Distance is a factor as essential as force. Infinite force could not +impart to a body the least velocity, could not develop the least energy, +without acting through distance. + +This exposition of the nature of momentum is sufficient for my present +purpose. I shall have occasion to apply it later on, and to describe the +methods of balancing this force, in those cases in which it becomes +necessary or desirable to do so. At present I will proceed to consider +the second of the forces, or manifestations of force, which are +developed in moving bodies--_centrifugal force_. + +This force presents its claims to attention in all bodies which revolve +about fixed centers, and sometimes these claims are presented with a +good deal of urgency. At the same time, there is probably no subject, +about which the ideas of men generally are more vague and confused. This +confusion is directly due to the vague manner in which the subject of +centrifugal force is treated, even by our best writers. As would then +naturally be expected, the definitions of it commonly found in our +handbooks are generally indefinite, or misleading, or even absolutely +untrue. + +Before we can intelligently consider the principles and methods of +balancing this force, we must get a correct conception of the nature of +the force itself. What, then, is centrifugal force? It is an extremely +simple thing; a very ordinary amount of mechanical intelligence is +sufficient to enable one to form a correct and clear idea of it. This +fact renders it all the more surprising that such inaccurate and +confused language should be employed in its definition. Respecting +writers, also, who use language with precision, and who are profound +masters of this subject, it must be said that, if it had been their +purpose to shroud centrifugal force in mystery, they could hardly have +accomplished this purpose more effectually than they have done, to minds +by whom it was not already well understood. + +Let us suppose a body to be moving in a circular path, around a center +to which it is firmly held; and let us, moreover, suppose the impelling +force, by which the body was put in motion, to have ceased; and, also, +that the body encounters no resistance to its motion. It is then, by our +supposition, moving in its circular path with a uniform velocity, +neither accelerated nor retarded. Under these conditions, what is the +force which is being exerted on this body? Clearly, there is only one +such force, and that is, the force which holds it to the center, and +compels it, in its uniform motion, to maintain a fixed distance from +this center. This is what is termed centripetal force. It is obvious, +that the centripetal force, which holds this revolving body _to_ the +center, is the only force which is being exerted upon it. + +Where, then, is the centrifugal force? Why, the fact is, there is not +any such thing. In the dynamical sense of the term "force," the sense in +which this term is always understood in ordinary speech, as something +tending to produce motion, and the direction of which determines the +direction in which motion of a body must take place, there is, I repeat, +no such thing as centrifugal force. + +There is, however, another sense in which the term "force" is employed, +which, in distinction from the above, is termed a statical sense. This +"statical force" is the force by the exertion of which a body keeps +still. It is the force of inertia--the resistance which all matter +opposes to a dynamical force exerted to put it in motion. This is the +sense in which the term "force" is employed in the expression +"centrifugal force." Is that all? you ask. Yes; that is all. + +I must explain to you how it is that a revolving body exerts this +resistance to being put in motion, when all the while it _is_ in motion, +with, according to our above supposition, a uniform velocity. The first +law of motion, so far as we now have occasion to employ it, is that a +body, when put in motion, moves in a straight line. This a moving body +always does, unless it is acted on by some force, other than its +impelling force, which deflects it, or turns it aside, from its direct +line of motion. A familiar example of this deflecting force is afforded +by the force of gravity, as it acts on a projectile. The projectile, +discharged at any angle of elevation, would move on in a straight line +forever, but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made to +fall, by the attraction of the earth; and so instead of a straight line +it describes a curve, known as the trajectory. + +Now a revolving body, also, has the same tendency to move in a straight +line. It would do so, if it were not continually deflected from this +line. Another force is constantly exerted upon it, compelling it, at +every successive point of its path, to leave the direct line of motion, +and move on a line which is everywhere equally distant from the center +to which it is held. If at any point the revolving body could get free, +and sometimes it does get free, it would move straight on, in a line +tangent to the circle at the point of its liberation. But if it cannot +get free, it is compelled to leave each new tangential direction, as +soon as it has taken it. + +This is illustrated in the above figure. The body, A, is supposed to be +revolving in the direction indicated by the arrow, in the circle, A B F +G, around the center, O, to which it is held by the cord, O A. At the +point, A, it is moving in the tangential direction, A D. It would +continue to move in this direction, did not the cord, O A, compel it to +move in the arc, A C. Should this cord break at the point, A, the body +would move; straight on toward D, with whatever velocity it had. + +You perceive now what centrifugal force is. This body is moving in the +direction, A D. The centripetal force, exerted through the cord, O A, +pulls it aside from this direction of motion. The body resists this +deflection, and this resistance is its centrifugal force. + +[Illustration: Fig. 1] + +Centrifugal force is, then, properly defined to be the disposition of a +revolving body to move in a straight line, and the resistance which such +a body opposes to being drawn aside from a straight line of motion. The +force which draws the revolving body continually to the center, or the +deflecting force, is called the centripetal force, and, aside from the +impelling and retarding forces which act in the direction of its motion, +the centripetal force is, dynamically speaking, the only force which is +exerted on the body. + +It is true, the resistance of the body furnishes the measure of the +centripetal force. That is, the centripetal force must be exerted in a +degree sufficient to overcome this resistance, if the body is to move in +the circular path. In this respect, however, this case does not differ +from every other case of the exertion of force. Force is always exerted +to overcome resistance: otherwise it could not be exerted. And the +resistance always furnishes the exact measure of the force. I wish to +make it entirely clear, that in the dynamical sense of the term "force," +there is no such thing as centrifugal force. The dynamical force, that +which produces motion, is the centripetal force, drawing the body +continually from the tangential direction, toward the center; and what +is termed centrifugal force is merely the resistance which the body +opposes to this deflection, _precisely like any other resistance to a +force_. + +The centripetal force is exerted on the radial line, as on the line, A +O, Fig. 1, at right angles with the direction in which the body is +moving; and draws it directly toward the center. It is, therefore, +necessary that the resistance to this force shall also be exerted on the +same line, in the opposite direction, or directly from the center. But +this resistance has not the least power or tendency to produce motion in +the direction in which it is exerted, any more than any other resistance +has. + +We have been supposing a body to be firmly held to the center, so as to +be compelled to revolve about it in a fixed path. But the bond which +holds it to the center may be elastic, and in that case, if the +centrifugal force is sufficient, the body will be drawn from the center, +stretching the elastic bond. It may be asked if this does not show +centrifugal force to be a force tending to produce motion from the +center. This question is answered by describing the action which really +takes place. The revolving body is now imperfectly deflected. The bond +is not strong enough to compel it to leave its direct line of motion, +and so it advances a certain distance along this tangential line. This +advance brings the body into a larger circle, and by this enlargement of +the circle, assuming the rate of revolution to be maintained, its +centrifugal force is proportionately increased. The deflecting power +exerted by the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct path; +and when the limit of its elasticity is reached, the deflecting bond +will be broken. If, however, the strength of the deflecting bond is +increased by its elongation in a more rapid ratio than the centrifugal +force is increased by the enlargement of the circle, then a point will +be reached in which the centripetal force will be sufficient to compel +the body to move again in the circular path. + +Sometimes the centripetal force is weak, and opportunity is afforded to +observe this action, and see its character exhibited. A common example +of weak centripetal force is the adhesion of water to the face of a +revolving grindstone. Here we see the deflecting force to become +insufficient to compel the drops of water longer to leave their direct +paths, and so these do not longer leave their direct paths, but move on +in those paths, with the velocity they have at the instant of leaving +the stone, flying off on tangential lines. + +If, however, a fluid be poured on the side of the revolving wheel near +the axis, it will move out to the rim on radial lines, as may be +observed on car wheels universally. The radial lines of black oil on +these wheels look very much as if centrifugal force actually did produce +motion, or had at least a very decided tendency to produce motion, in +the radial direction. This interesting action calls for explanation. In +this action the oil moves outward gradually, or by inconceivably minute +steps. Its adhesion being overcome in the least possible degree, it +moves in the same degree tangentially. In so doing it comes in contact +with a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it had +overcome the adhesion. Motion in the radial direction is the result of +these two actions, namely, leaving the first point of contact +tangentially and receiving an acceleration of its motion, so that this +shall be equal to that of the second point of contact. When we think +about the matter a little closely, we see that at the rim of the wheel +the oil has perhaps ten times the velocity of revolution which it had on +leaving the journal, and that the mystery to be explained really is, How +did it get that velocity, moving out on a radial line? Why was it not +left behind at the very first? Solely by reason of its forward +tangential motion. That is the answer. + +When writers who understand the subject talk about the centripetal and +centrifugal forces being different names for the same force, and about +equal action and reaction, and employ other confusing expressions, just +remember that all they really mean is to express the universal relation +between force and resistance. The expression "centrifugal force" is +itself so misleading, that it becomes especially important that the real +nature of this so-called force, or the sense in which the term "force" +is used in this expression, should be fully explained.[1] This force is +now seen to be merely the tendency of a revolving body to move in a +straight line, and the resistance which it opposes to being drawn aside +from that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see. + +[Footnote 1: I was led to study this subject in looking to see what had +become of my first permanent investment, a small venture, made about +thirty-five years ago, in the "Sawyer and Gwynne static pressure +engine." This was the high-sounding name of the Keely motor of that day, +an imposition made possible by the confused ideas prevalent on this very +subject of centrifugal force.] + +FIRST.--I have called your attention to the fact that the direction in +which the revolving body is deflected from the tangential line of motion +is toward the center, on the radial line, which forms a right angle with +the tangent on which the body is moving. The first question that +presents itself is this: What is the measure or amount of this +deflection? The answer is, this measure or amount is the versed sine of +the angle through which the body moves. + +Now, I suspect that some of you--some of those whom I am directly +addressing--may not know what the versed sine of an angle is; so I must +tell you. We will refer again to Fig. 1. In this figure, O A is one +radius of the circle in which the body A is revolving. O C is another +radius of this circle. These two radii include between them the angle A +O C. This angle is subtended by the arc A C. If from the point O we let +fall the line C E perpendicular to the radius O A, this line will divide +the radius O A into two parts, O E and E A. Now we have the three +interior lines, or the three lines within the circle, which are +fundamental in trigonometry. C E is the sine, O E is the cosine, and E A +is the versed sine of the angle A O C. Respecting these three lines +there are many things to be observed. I will call your attention to the +following only: + +_First_.--Their length is always less than the radius. The radius is +expressed by 1, or unity. So, these lines being less than unity, their +length is always expressed by decimals, which mean equal to such a +proportion of the radius. + +_Second_.--The cosine and the versed sine are together equal to the +radius, so that the versed sine is always 1, less the cosine. + +_Third_.--If I diminish the angle A O C, by moving the radius O C toward +O A, the sine C E diminishes rapidly, and the versed sine E A also +diminishes, but more slowly, while the cosine O E increases. This you +will see represented in the smaller angles shown in Fig. 2. If, finally, +I make O C to coincide with O A, the angle is obliterated, the sine and +the versed sine have both disappeared, and the cosine has become the +radius. + +_Fourth_.--If, on the contrary, I enlarge the angle A O C by moving the +radius O C toward O B, then the sine and the versed sine both increase, +and the cosine diminishes; and if, finally, I make O C coincide with O +B, then the cosine has disappeared, the sine has become the radius O B, +and the versed sine has become the radius O A, thus forming the two +sides inclosing the right angle A O B. The study of this explanation +will make you familiar with these important lines. The sine and the +cosine I shall have occasion to employ in the latter part of my lecture. +Now you know what the versed sine of an angle is, and are able to +observe in Fig. 1 that the versed sine A E, of the angle A O C, +represents in a general way the distance that the body A will be +deflected from the tangent A D toward the center O while describing the +arc A C. + +The same law of deflection is shown, in smaller angles, in Fig. 2. In +this figure, also, you observe in each of the angles A O B and A O C +that the deflection, from the tangential direction toward the center, of +a body moving in the arc A C is represented by the versed sine of the +angle. The tangent to the arc at A, from which this deflection is +measured, is omitted in this figure to avoid confusion. It is shown +sufficiently in Fig. 1. The angles in Fig. 2 are still pretty large +angles, being 12° and 24° respectively. These large angles are used for +convenience of illustration; but it should be explained that this law +does not really hold in them, as is evident, because the arc is longer +than the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent and +arc coincide, and approximately so for exceedingly small angles. + +[Illustration: Fig. 2] + +In reality, however, we have only to do with the case in which the arc +and the tangent do coincide, and in which the law that the deflection is +_equal to_ the versed sine of the angle is absolutely true. Here, in +observing this most familiar thing, we are, at a single step, taken to +that which is utterly beyond our comprehension. The angles we have to +consider disappear, not only from our sight, but even from our +conception. As in every other case when we push a physical investigation +to its limit, so here also, we find our power of thought transcended, +and ourselves in the presence of the infinite. + +We can discuss very small angles. We talk familiarly about the angle +which is subtended by 1" of arc. On Fig. 2, a short line is drawn near +to the radius O A'. The distance between O A' and this short line is 1° +of the arc A' B'. If we divide this distance by 3,600, we get 1" of arc. +The upper line of the Table of versed sines given below is the versed +sine of 1" of arc. It takes 1,296,000 of these angles to fill a circular +space. These are a great many angles, but they do not make a circle. +They make a polygon. If the radius of the circumscribed circle of this +polygon is 1,296,000 feet, which is nearly 213 geographical miles, each +one of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon would be +one-sixtieth of a geographical mile, or 101.46 feet. On the orbit of the +moon, at its mean distance from the earth, each of these straight sides +would be about 6,000 feet long. + +The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never can +reach the circle. When you swing a sling around your head, and feel the +uniform stress exerted on your hand through the cord, you are made aware +of an action which is entirely beyond the grasp of our minds and the +reach of our analysis. + +So always in practical operation that law is absolutely true which we +observe to be approximated to more and more nearly as we consider +smaller and smaller angles, that the versed sine of the angle is the +measure of its deflection from the straight line of motion, or the +measure of its fall toward the center, which takes place at every point +in the motion of a revolving body. + +Then, assuming the absolute truth of this law of deflection, we find +ourselves able to explain all the phenomena of centrifugal force, and to +compute its amount correctly in all cases. + +We have now advanced two steps. We have learned _the direction_ and _the +measure_ of the deflection, which a revolving body continually suffers, +and its resistance to which is termed centrifugal force. The direction +is toward the center, and the measure is the versed sine of the angle. + +SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that the +amount of centrifugal force exerted by a revolving body varies in four +ways. + +_First_.--Directly as the weight of the body. + +_Second_.--In a given circle of revolution, as the square of the speed +or of the number of revolutions per minute; which two expressions in +this case mean the same thing. + +_Third_.--With a given number of revolutions per minute, or a given +angular velocity[1] _directly_ as the radius of the circle; and + +_Fourth_.--With a given actual velocity, or speed in feet per minute, +_inversely_ as the radius of the circle. + +[Footnote 1: A revolving body is said to have the same angular velocity, +when it sweeps through equal angles in equal times. Its actual velocity +varies directly as the radius of the circle in which it is revolving.] + +Of course there is a reason for these laws. You are not to learn them by +rote, or to accept them on any authority. You are taught not to accept +any rule or formula on authority, but to demand the reason for it--to +give yourselves no rest until you know the why and wherefore, and +comprehend these fully. This is education, not cramming the mind with +mere facts and rules to be memorized, but drawing out the mental powers +into activity, strengthening them by use and exercise, and forming the +habit, and at the same time developing the power, of penetrating to the +reason of things. + +In this way only, you will be able to meet the requirement of a great +educator, who said: "I do not care to be told what a young man knows, +but what he can _do_." I wish here to add my grain to the weight of +instruction which you receive, line upon line, precept on precept, on +this subject. + +The reason for these laws of centrifugal force is an extremely simple +one. The first law, that this force varies directly as the weight of the +body, is of course obvious. We need not refer to this law any further. +The second, third, and fourth laws merely express the relative rates at +which a revolving body is deflected from the tangential direction of +motion, in each of the three cases described, and which cases embrace +all possible conditions. + +These three rates of deflection are exhibited in Fig. 2. An examination +of this figure will give you a clear understanding of them. Let us first +suppose a body to be revolving about the point, O, as a center, in a +circle of which A B C is an arc, and with a velocity which will carry it +from A to B in one second of time. Then in this time the body is +deflected from the tangential direction a distance equal to A D, the +versed sine of the angle A O B. Now let us suppose the velocity of this +body to be doubled in the same circle. In one second of time it moves +from A to C, and is deflected from the tangential direction of motion a +distance equal to A E, the versed sine of the angle, A O C. But A E is +four times A D. Here we see in a given circle of revolution the +deflection varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded. + +The following table will show, by comparison of the versed sines of very +small angles, the deflection in a given circle varying as the square of +the speed, when we penetrate to them, so nearly that the error is not +disclosed at the fifteenth place of decimals. + + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 + +You observe the deflection for 10" of arc is 100 times as great, and for +100" of arc is 10,000 times as great as it is for 1" of arc. So far as +is shown by the 15th place of decimals, the versed sine varies as the +square of the angle; or, in a given circle, the deflection, and so the +centrifugal force, of a revolving body varies as the square of the +speed. + +The reason for the third law is equally apparent on inspection of Fig. +2. It is obvious, that in the case of bodies making the same number of +revolutions in different circles, the deflection must vary directly as +the diameter of the circle, because for any given angle the versed sine +varies directly as the radius. Thus radius O A' is twice radius O A, and +so the versed sine of the arc A' B' is twice the versed sine of the arc +A B. Here, while the angular velocity is the same, the actual velocity +is doubled by increase in the diameter of the circle, and so the +deflection is doubled. This exhibits the general law, that with a given +angular velocity the centrifugal force varies directly as the radius or +diameter of the circle. + +We come now to the reason for the fourth law, that, with a given actual +velocity, the centrifugal force varies _inversely_ as the diameter of +the circle. If any of you ever revolved a weight at the end of a cord +with some velocity, and let the cord wind up, suppose around your hand, +without doing anything to accelerate the motion, then, while the circle +of revolution was growing smaller, the actual velocity continuing nearly +uniform, you have felt the continually increasing stress, and have +observed the increasing angular velocity, the two obviously increasing +in the same ratio. That is the operation or action which the fourth law +of centrifugal force expresses. An examination of this same figure (Fig. +2) will show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. If we +take the velocity A' B', double the velocity A B, and transfer it to the +smaller circle, we have the velocity A C. But the deflection has been +increasing as we have reduced the circle, and now with one half the +radius it is twice as great. It has increased in the same ratio in which +the angular velocity has increased. Thus we see the simple and necessary +nature of these laws. They merely express the different rates of +deflection of a revolving body in these different cases. + +THIRD.--We have a coefficient of centrifugal force, by which we are +enabled to compute the amount of this resistance of a revolving body to +deflection from a direct line of motion in all cases. This is that +coefficient. The centrifugal force of a body making _one_ revolution per +minute, in a circle of _one_ foot radius, is 0.000341 of the weight of +the body. + +According to the above laws, we have only to multiply this coefficient +by the square of the number of revolutions made by the body per minute, +and this product by the radius of the circle in feet, or in decimals of +a foot, and we have the centrifugal force, in terms of the weight of the +body. Multiplying this by the weight of the body in pounds, we have the +centrifugal force in pounds. + +Of course you want to know how this coefficient has been found out, and +how you can be sure it is correct. I will tell you a very simple way. +There are also mathematical methods of ascertaining this coefficient, +which your professors, if you ask them, will let you dig out for +yourselves. The way I am going to tell you I found out for myself, and +that, I assure you, is the only way to learn anything, so that it will +stick; and the more trouble the search gives you, the darker the way +seems, and the greater the degree of perseverance that is demanded, the +more you will appreciate the truth when you have found it, and the more +complete and permanent your possession of it will be. + +The explanation of this method may be a little more abstruse than the +explanations already given, but it is very simple and elegant when you +see it, and I fancy I can make it quite clear. I shall have to preface +it by the explanation of two simple laws. The first of these is, that a +body acted on by a constant force, so as to have its motion uniformly +accelerated, suppose in a straight line, moves through distances which +increase as the square of the time that the accelerating force continues +to be exerted. + +The necessary nature of this law, or rather the action of which this law +is the expression, is shown in Fig. 3. + +[Illustration: Fig. 3] + +Let the distances A B, B C, C D, and D E in this figure represent four +successive seconds of time. They may just as well be conceived to +represent any other equal units, however small. Seconds are taken only +for convenience. At the commencement of the first second, let a body +start from a state of rest at A, under the action of a constant force, +sufficient to move it in one second through a distance of one foot. This +distance also is taken only for convenience. At the end of this second, +the body will have acquired a velocity of two feet per second. This is +obvious because, in order to move through one foot in this second, the +body must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. Its +motion increased uniformly. Therefore, at the termination of the second +its velocity must have reached two feet per second. Let the triangle A B +F represent this accelerated motion, and the distance, of one foot, +moved through during the first second, and let the line B F represent +the velocity of two feet per second, acquired by the body at the end of +it. Now let us imagine the action of the accelerating force suddenly to +cease, and the body to move on merely with the velocity it has acquired. +During the next second it will move through two feet, as represented by +the square B F C I. But in fact, the action of the accelerating force +does not cease. This force continues to be exerted, and produces on the +body during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity accelerated +two additional feet per second, as represented by the line I G. So in +two seconds the body has moved through four feet. We may follow the +operation of this law as far as we choose. The figure shows it during +four seconds, or any other unit, of time, and also for any unit of +distance. Thus: + + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 + +So it is obvious that the distance moved through by a body whose motion +is uniformly accelerated increases as the square of the time. + +But, you are asking, what has all this to do with a revolving body? As +soon as your minds can be started from a state of rest, you will +perceive that it has everything to do with a revolving body. The +centripetal force, which acts upon a revolving body to draw it to the +center, is a constant force, and under it the revolving body must move +or be deflected through distances which increase as the squares of the +times, just as any body must do when acted on by a constant force. To +prove that a revolving body obeys this law, I have only to draw your +attention to Fig. 2. Let the equal arcs, A B and B C, in this figure +represent now equal times, as they will do in case of a body revolving +in this circle with a uniform velocity. The versed sines of the angles, +A O B and A O C, show that in the time, A C, the revolving body was +deflected four times as far from the tangent to the circle at A as it +was in the time, A B. So the deflection increased as the square of the +time. If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute angles, +absolutely so far as appears up to the fifteenth place of decimals, as +the square of the time. + +The standard from which all computations are made of the distances +passed through in given times by bodies whose motion is uniformly +accelerated, and from which the velocity acquired is computed when the +accelerating force is known, and the force is found when the velocity +acquired or the rate of acceleration is known, is the velocity of a body +falling to the earth. It has been established by experiment, that in +this latitude near the level of the sea, a falling body in one second +falls through a distance of 16.083 feet, and acquires a velocity of +32.166 feet per second; or, rather, that it would do so if it did not +meet the resistance of the atmosphere. In the case of a falling body, +its weight furnishes, first, the inertia, or the resistance to motion, +that has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the earth, or +the force exerted to overcome its resistance. Here, as in all possible +cases, the force and the resistance are identical with each other. The +above is, therefore, found in this way to be the rate at which the +motion of any body will be accelerated when it is acted on by a constant +force equal to its weight, and encounters no resistance. + +It follows that a revolving body, when moving uniformly in any circle at +a speed at which its deflection from a straight line of motion is such +that in one second this would amount to 16.083 feet, requires the +exertion of a centripetal force equal to its weight to produce such +deflection. The deflection varying as the square of the time, in 0.01 of +a second this deflection will be through a distance of 0.0016083 of a +foot. + +Now, at what speed must a body revolve, in a circle of one foot radius, +in order that in 0.01 of one second of time its deflection from a +tangential direction shall be 0.0016083 of a foot? This decimal is the +versed sine of the arc of 3°15', or of 3.25°. This angle is so small +that the departure from the law that the deflection is equal to the +versed sine of the angle is too slight to appear in our computation. +Therefore, the arc of 3.25° is the arc of a circle of one foot radius +through which a body must revolve in 0.01 of a second of time, in order +that the centripetal force, and so the centrifugal force, shall be equal +to its weight. At this rate of revolution, in one second the body will +revolve through 325°, which is at the rate of 54.166 revolutions per +minute. + +Now there remains only one question more to be answered. If at 54.166 +revolutions per minute the centrifugal force of a body is equal to its +weight, what will its centrifugal force be at one revolution per minute +in the same circle? + +To answer this question we have to employ the other extremely simple +law, which I said I must explain to you. It is this: The acceleration +and the force vary in a constant ratio with each other. Thus, let force +1 produce acceleration 1, then force 1 applied again will produce +acceleration 1 again, or, in other words, force 2 will produce +acceleration 2, and so on. This being so, and the amount of the +deflection varying as the squares of the speeds in the two cases, the +centrifugal force of a body making one revolution per minute in a circle +of + + 1² + one foot radius will be ---------- = 0.000341 + 54.166² + +--the coefficient of centrifugal force. + +There is another mode of making this computation, which is rather neater +and more expeditious than the above. A body making one revolution per +minute in a circle of one foot radius will in one second revolve through +an arc of 6°. The versed sine of this arc of 6° is 0.0054781046 of a +foot. This is, therefore, the distance through which a body revolving at +this rate will be deflected in one second. If it were acted on by a +force equal to its weight, it would be deflected through the distance of +16.083 feet in the same time. What is the deflecting force actually +exerted upon it? Of + + 0.0054781046 +course, it is ------------. + 16.083 + +This division gives 0.000341 of its weight as such deflecting force, the +same as before. + +In taking the versed sine of 6°, a minute error is involved, though not +one large enough to change the last figure in the above quotient. The +law of uniform acceleration does not quite hold when we come to an angle +so large as 6°. If closer accuracy is demanded, we can attain it, by +taking the versed sine for 1°, and multiplying this by 6². This gives as +a product 0.0054829728, which is a little larger than the versed sine of +6°. + +I hope I have now kept my promise, and made it clear how the coefficient +of centrifugal force may be found in this simple way. + +We have now learned several things about centrifugal force. Let me +recapitulate. We have learned: + +1st. The real nature of centrifugal force. That in the dynamical sense +of the term force, this is not a force at all: that it is not capable of +producing motion, that the force which is really exerted on a revolving +body is the centripetal force, and what we are taught to call +centrifugal force is nothing but the resistance which a revolving body +opposes to this force, precisely like any other resistance. + +2d. The direction of the deflection, to which the centrifugal force is +the resistance, which is straight to the center. + +3d. The measure of this deflection; the versed sine of the angle. + +4th. The reason of the laws of centrifugal force; that these laws merely +express the relative amount of the deflection, and so the amount of the +force required to produce the deflection, and of the resistance of the +revolving body to it, in all different cases. + +5th. That the deflection of a revolving body presents a case analogous +to that of uniformly accelerated motion, under the action of a constant +force, similar to that which is presented by falling bodies;[1] and +finally, + +6th. How to find the coefficient, by which the amount of centrifugal +force exerted in any case may be computed. + +[Footnote 1: A body revolving with a uniform velocity in a horizontal +plane would present the only case of uniformly accelerated motion that +is possible to be realized under actual conditions.] + +I now pass to some other features. + +_First_.--You will observe that, relatively to the center, a revolving +body, at any point in its revolution, is at rest. That is, it has no +motion, either from or toward the center, except that which is produced +by the action of the centripetal force. It has, therefore, this identity +also with a falling body, that it starts from a state of rest. This +brings us to a far more comprehensive definition of centrifugal force. +This is the resistance which a body opposes to being put in motion, at +any velocity acquired in any time, from a state of rest. Thus +centrifugal force reveals to us the measure of the inertia of matter. +This inertia may be demonstrated and exhibited by means of apparatus +constructed on this principle quite as accurately as it can be in any +other way. + +_Second_.--You will also observe the fact, that motion must be imparted +to a body gradually. As distance, _through_ which force can act, is +necessary to the impartation of velocity, so also time, _during_ which +force can act, is necessary to the same result. We do not know how +motion from a state of rest begins, any more than we know how a polygon +becomes a circle. But we do know that infinite force cannot impart +absolutely instantaneous motion to even the smallest body, or to a body +capable of opposing the least resistance. Time being an essential +element or factor in the impartation of velocity, if this factor be +omitted, the least resistance becomes infinite. + +We have a practical illustration of this truth in the explosion of +nitro-glycerine. If a small portion of this compound be exploded on the +surface of a granite bowlder, in the open air, the bowlder will be rent +into fragments. The explanation of this phenomenon common among the +laborers who are the most numerous witnesses of it, which you have +doubtless often heard, and which is accepted by ignorant minds without +further thought, is that the action of nitro-glycerine is downward. We +know that such an idea is absurd. + +The explosive force must be exerted in all directions equally. The real +explanation is, that the explosive action of nitro-glycerine is so +nearly instantaneous, that the resistance of the atmosphere is very +nearly equal to that of the rock; at any rate, is sufficient to cause +the rock to be broken up. The rock yields to the force very nearly as +readily as the atmosphere does. + +_Third_. An interesting solution is presented here of what is to many an +astronomical puzzle. When I was younger than I am now, I was greatly +troubled to understand how it could be that if the moon was always +falling to the earth, as the astronomers assured us it was, it should +never reach it, nor have its falling velocity accelerated. In popular +treatises on astronomy, such for example as that of Professor Newcomb, +this is explained by a diagram in which the tangential line is carried +out as in Fig. 1, and by showing that in falling from the point A to the +earth as a center, through distances increasing as the square of the +time, the moon, having the tangential velocity that it has, could never +get nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this long +tangential line has nothing to do with the motion of the moon, and while +we are compelled to assent to the demonstration, we want something +better. To my mind the better and more satisfactory explanation is found +in the fact that the moon is forever commencing to fall, and is +continually beginning to fall in a new direction. A revolving body, as +we have seen, never gets past that point, which is entirely beyond our +sight and our comprehension, of beginning to fall, before the direction +of its fall is changed. So, under the attraction of the earth, the moon +is forever leaving a new tangential direction of motion at the same +rate, without acceleration. + +(_To be continued_.) + + * * * * * + + + + +COMPRESSED AIR POWER SCHEMES. + +By J. STURGEON, Engineer of the Birmingham Compressed Air Power Company. + + +In the article on "Gas, Air, and Water Power" in the _Journal_ for Dec. +8 last, you state that you await with some curiosity my reply to certain +points in reference to the compressed air power schemes alluded to in +that article. I now, therefore, take the liberty of submitting to you +the arguments on my side of the question (which are substantially the +same as those I am submitting to Mr. Hewson, the Borough Engineer of +Leeds). The details and estimates for the Leeds scheme are not yet in a +forward enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system in +other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters of +detail. We have, however, recently succeeded in obtaining a suitable +place, and making arrangements for railway siding, water supply, etc.; +and we hope to be in a position to start early in the present year. + +I inclose (1) a tabulated summary of the estimates for Birmingham +divided into stages of 3,000 gross indicated horse power at a time; (2) +a statement showing the cost to consumers in terms of indicated horse +power and in different modes, more or less economical, of applying the +air power in the consumers' engines; (3) a tracing showing the method of +laying the mains; (4) a tracing showing the method of collecting the +meter records at the central station, by means of electric apparatus, +and ascertaining the exact amount of leakage. A short description of the +two latter would be as well. + +TABLE I.--_Showing the Progressive Development of the Compressed Air +System in stages of 3000 Indicated Horse Power (gross) at a Time, and +the Profits at each Stage_ + +_____________________________________________________________________________ + +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- + +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- + +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| £12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | £25,595 | £25,595 | £25,595 | £25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | £82,455 | £124,714 | £167,094 | £209,455 | £251,795 | +----------------------------------------------------------------------------- + +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| £6,405 | £7,855 | £9,305 | £10,955 | £12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | £12,080 | £18,508 | £24,944 | £31,589 | £38,096 | +----------------------------------------------------------------------------- + +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- + +TABLE II.--_Cost of Air Power in Terms of Indicated Horse Power_. + +Abbreviated column headings: + +Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per +Hour. + +Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet. + +Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per +Cent. + +Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet. + +Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per +Cent. + +Abbreviated row headings: + +CASE 1.--Where air at 45 lbs. pressure is re-heated to 320° Fahr., and +expanded to atmospheric pressure. + +CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to +212° Fahr., and expanded to atmospheric pressure. + +CASE 3.--Where air is used expansively without re-heating, whereby +intensely cold air is exhausted, and may be used for ice making, &c. + +CASE 4.--Where air is heated to 212° Fahr., and the terminal pressure is +11.3 lbs. above that of the atmosphere + +CASE 5.--Where the air is used without heating, and cut off at one-third +of the stroke, as in ordinary slide-valve engines + +CASE 6.--Where the air is used without re-heating and without expansion. + + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | £ s. d. | £ s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 0½| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 5½ | 9 10 5½| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 5½ | 9 1 10½| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ + +The great thing to guard against is leakage. If the pipes were simply +buried in the ground, it would be almost impossible to trace leakage, or +even to know of its existence. The income of the company might be +wasting away, and the loss never suspected until the quarterly returns +from the meters were obtained from the inspectors. Only then would it be +discovered that there must be a great leak (or it might be several +leaks) somewhere. But how would it be possible to trace them among 20 or +30 miles of buried pipes? We cannot break up the public streets. The +very existence of the concern depends upon (1) the _daily_ checking of +the meter returns, and comparison with the output from the air +compressors, so as to ascertain the amount of leakage; (2) facility for +tracing the locality of a leak; and (3) easy access to the mains with +the minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the pipes +are laid in concrete troughs, near the surface of the road, with +removable concrete covers strong enough to stand any overhead traffic. +At intervals there are junctions for service connections, with street +boxes and covers serving as inspection chambers. These chambers are also +provided over the ball-valves, which serve as stop-valves in case of +necessity, and are so arranged that in case of a serious breach in the +portion of main between any two of them, the rush of air to the breach +will blow them up to the corresponding seats and block off the broken +portion of main. The air space around the pipe in the concrete trough +will convey for a long distance the whistling noise of a leak; and the +inspectors, by listening at the inspection openings, will thus be +enabled to rapidly trace their way almost to the exact spot where there +is an escape. They have then only to remove the top surface of road +metal and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring from +the nearest street opening, the inspectors would know where to break +open the road to arrive at the probable locality of the leak. A very +slight leak can be heard a long way off by its peculiar whistling sound. + +[Illustration: COMPRESSED AIR POWER] + +The next point is to obtain a daily report of the condition of the mains +and the amount of leakage. It would be impracticable to employ an army +of meter inspectors to take the records daily from all the meters in the +district. We therefore adopt the method of electric signaling shown in +the second drawing. In the engineer's office, at the central station, is +fixed the dial shown in Fig. 1. Each consumer's meter is fitted with the +contact-making apparatus shown in Pig. 4, and in an enlarged form in +Figs. 5 and 6, by which a current is sent round the electro-magnet, D +(Fig. 1), attracting the armature, and drawing the disk forward +sufficiently for the roller at I to pass over the center of one of the +pins, and so drop in between that and the next pin, thus completing the +motion, and holding the disk steadily opposite the figure. This action +takes place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose one +meter should be moving very slowly, and so retaining contact for some +time, while other meters were working rapidly; the armature at D would +then be held up to the magnet by the prolonged contact maintained by the +slow moving meter, and so prevent the quick working meters from +actuating it; and they would therefore pass the contact points without +recording. A meter might also stop dead at the point of contact on +shutting off the air, and so hold up the armature; thus preventing +others from acting. To obviate this, we apply the disengaging apparatus +shown at L (Fig. 4). The contact maker works on the center, m, having an +armature on its opposite end. On contact being made, at the same time +that the magnet, D, is operated, the one at L is also operated, +attracting the armature, and throwing over the end of the contact maker, +l¹, on to the non-conducting side of the pin on the disk. Thus the whole +movement is rendered practically instantaneous, and the magnet at D is +set at liberty for the next operation. A resistance can be interposed at +L, if necessary, to regulate the period of the operation. The whole of +the meters work the common dial shown in Fig. 1, on which the gross +results only are recorded; and this is all we want to know in this way. +The action is so rapid, owing to the use of the magnetic disengaging +gear, that the chances of two or more meters making contact at the same +moment are rendered extremely small. Should such a thing happen, it +would not matter, as it is only approximate results that we require in +this case; and the error, if any, would add to the apparent amount of +leakage, and so be on the right side. Of course, the record of each +consumer's meter would be taken by the inspector at the end of every +quarter, in order to make out the bill; and the totals thus obtained +would be checked by the gross results indicated by the main dial. In +this way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected to an +extremely accurate measurement. At the end of the working day, the +engineer has merely to take down from the dial in his office the total +record of air measured to the consumers, also the output of air from the +compressors, which he ascertains by means of a continuous counter on the +engines, and the difference between the two will represent the loss. If +the loss is trifling, he will pass it over; if serious, he will send out +his inspectors to trace it. Thus there could be no long continued +leakage, misuse, or robbery of the air, without the company becoming +aware of the fact, and so being enabled to take measures to stop or +prevent it. The foregoing are absolutely essential adjuncts to any +scheme of public motive power supply by compressed air, without which we +should be working in the dark, and could never be sure whether the +company were losing or making money. With them, we know where we are and +what we are doing. + +Referring to the estimates given in Table I., I may explain that the +item of repairs and renewals covers 10 per cent. on boilers and gas +producers, 5 per cent. on engines, 5 per cent. on buildings, and 5 per +cent. on mains. Considering that the estimates include ample fitting +shops, with the best and most suitable tools, and that the wages list +includes a staff of men whose chief work would be to attend to repairs, +etc., I think the above allowances ample. Each item also includes 5 per +cent. for contingencies. + +I have commenced by giving all the preceding detail, in order to show +the groundwork on which I base the estimate of the cost of compressed +air power to consumers, in terms of indicated horse power per annum, as +given in Table II. I may say that, in estimating the engine power and +coal consumption, I have not, as in the original report, made purely +theoretical calculations, but have taken diagrams from engines in actual +use (although of somewhat smaller size than those intended to be +employed), and have worked out the results therefrom. It will, I hope, +be seen that, with all the safeguards we have provided, we may fairly +reckon upon having for sale the stated quantity of air produced by means +of the plant, as estimated, and at the specified annual cost; and that +therefore the statement of cost per indicated horse power per annum may +be fairly relied upon. Thus the cost of compressed air to the consumer, +based upon an _average_ charge of 5d. per 1,000 cubic feet, will vary +from £6 14s. per indicated horse power per annum to £18 13s. 3d., +according to circumstances and mode of application. + +A compressed air motor is an exceedingly simple machine--much simpler +than an ordinary steam engine. But the air may also be used in an +ordinary steam engine; and in this case it can be much simplified in +many details. Very little packing is needed, as there is no nuisance +from gland leakage; the friction is therefore very slight. Pistons and +glands are packed with soapstone, or other self-lubricating packing; and +no oil is required except for bearings, etc. The company will undertake +the periodical inspection and overhauling of engines supplied with their +power, all which is included in the estimates. The total cost to +consumers, with air at an average of 5d. per 1,000 cubic feet, may +therefore be fairly taken as follows: + + Min. Max. + Cost of air used £6 14 0½ £18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 12½ per cent. on + £10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + £8 19 0½ £20 18 3 + +The maximum case would apply only to direct acting engines, such as +Tangye pumps, air power hammers, etc., where the air is full on till the +end of the stroke, and where there is no expansion. The minimum given is +at the average rate of 5d. per 1,000 cubic feet; but as there will be +rates below this, according to a sliding scale, we may fairly take it +that the lowest charge will fall considerably below £6 per indicated +horse power per annum.--_Journal of Gas Lighting_. + + * * * * * + + + + +THE BERTHON COLLAPSIBLE CANOE. + + +An endeavor has often been made to construct a canoe that a person can +easily carry overland and put into the water without aid, and convert +into a sailboat. The system that we now call attention to is very well +contrived, very light, easily taken apart, and for some years past has +met with much favor. + +[Illustration: FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.] + +Mr. Berthon's canoes are made of impervious oil-skin. Form is given them +by two stiff wooden gunwales which are held in position by struts that +can be easily put in and taken out. The model shown in the figure is +covered with oiled canvas, and is provided with a double paddle and a +small sail. Fig. 2 represents it collapsed and being carried overland. + +[Illustration: FIG. 2.--THE SAME BEING CARRIED OVERLAND.] + +Mr. Berthon is manufacturing a still simpler style, which is provided +with two oars, as in an ordinary canoe. This model, which is much used +in England by fishermen and hunters, has for several years past been +employed in the French navy, in connection with movable defenses. At +present, every torpedo boat carries one or two of these canoes, each +composed of two independent halves that may be put into the water +separately or be joined together by an iron rod. + +These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure without +danger.[1]--_La Nature_. + +[Footnote 1: For detailed description see SUPPLEMENT, No. 84.] + + * * * * * + + + + +THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN STEAM +RAILROAD. + + +There was great excitement in Nürnberg on the 7th of December, 1835, on +which day the first German railroad was opened. The great square on +which the buildings of the Nürnberg and Furth "Ludwig's Road" stood, the +neighboring streets, and, in fact, the whole road between the two +cities, was filled with a crowd of people who flocked from far and near +to see the wonderful spectacle. For the first time, a railroad train +filled with passengers was to be drawn from Nürnberg to Furth by the +invisible power of the steam horse. At eight o'clock in the morning, the +civil and military authorities, etc., who took part in the celebration +were assembled on the square, and the gayly decorated train started off +to an accompaniment of music, cannonading, cheering, etc. Everything +passed off without an accident; the work was a success. The engraving in +the lower right-hand corner represents the engine and cars of this road. + +It will be plainly seen that such a revolution could not be accomplished +easily, and that much sacrifice and energy were required of the leaders +in the enterprise, prominent among whom was the merchant Johannes +Scharrer, who is known as the founder of the "Ludwig's Road." + +One would naturally suppose that such an undertaking would have met with +encouragement from the Bavarian Government, but this was not the case. +The starters of the enterprise met with opposition on every side; much +was written against it, and many comic pictures were drawn showing +accidents which would probably occur on the much talked of road. Two of +these pictures are shown in the accompanying large engraving, taken from +the _Illustrirte Zeitung_. As shown in the center picture, right hand, +it was expected by the railway opponents that trains running on tracks +at right angles must necessarily come in collision. If anything happened +to the engine, the passengers would have to get out and push the cars, +as shown at the left. + +[Illustration: JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF THE +OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--AT NURNBERG] + +Much difficulty was experienced in finding an engineer capable of +attending to the construction of the road; and at first it was thought +that it would be best to engage an Englishman, but finally Engineer +Denis, of Munich, was appointed. He had spent much time in England and +America studying the roads there, and carried on this work to the entire +satisfaction of the company. + +All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to be +given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first prize in +the competitive trials at Rainhill in 1829, delivered an engine of ten +horse power, which is still known in Nürnberg as "Der Englander." + +Fifty years have passed, and, as Johannes Scharrer predicted, the +Ludwig's Road has become a permanent institution, though it now forms +only a very small part of the network of railroads which covers every +portion of Germany. What changes have been made in railroads during +these fifty years! Compare the present locomotives with the one made by +Cugnot in 1770, shown in the upper left-hand cut, and with the work of +the pioneer Geo. Stephenson, who in 1825 constructed the first passenger +railroad in England, and who established a locomotive factory in +Newcastle in 1824. Geo. Stephenson was to his time what Mr. Borsig, +whose great works at Moabit now turn out from 200 to 250 locomotives a +year, is to our time. + +Truly, in this time there can be no better occasion for a celebration of +this kind than the fiftieth anniversary of the opening of the first +German railroad, which has lately been celebrated by Nürnberg and Furth. + +The lower left-hand view shows the locomotive De Witt Clinton, the third +one built in the United States for actual service, and the coaches. The +engine was built at the West Point Foundry, and was successfully tested +on the Mohawk and Hudson Railroad between Albany and Schenectady on Aug. +9, 1831. + + * * * * * + + + + +IMPROVED COAL ELEVATOR. + + +An illustration of a new coal elevator is herewith presented, which +presents advantages over any incline yet used, so that a short +description may be deemed interesting to those engaged in the coaling +and unloading of vessels. The pen sketch shows at a glance the +arrangement and space the elevator occupies, taking less ground to do +the same amount of work than any other mode heretofore adopted, and the +first cost of erecting is about the same as any other. + +When the expense of repairing damages caused by the ravages of winter is +taken into consideration, and no floats to pump out or tracks to wash +away, the advantages should be in favor of a substantial structure. + +The capacity of this hoist is to elevate 80,000 bushels in ten hours, at +less than one-half cent per bushel, and put coal in elevator, yard, or +shipping bins. + +[Illustration: IMPROVED COAL ELEVATOR.] + +The endless wire rope takes the cars out and returns them, dispensing +with the use of train riders. + +A floating elevator can distribute coal at any hatch on steam vessels, +as the coal has to be handled but once; the hoist depositing an empty +car where there is a loaded one in boat or barge, requiring no swing of +the vessel. + +Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor and +builder, and has them in use in the U.S. engineering service.--_Coal +Trade Journal_. + + * * * * * + + + + +STEEL-MAKING LADLES. + + +The practice of carrying melted cast iron direct from the blast furnace +to the Siemens hearth or the Bessemer converter saves both money and +time. It has rendered necessary the construction of special plant in the +form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson & +Co., of Preston, make the construction of these ladles a specialty, and +by their courtesy, says _The Engineer_, we are enabled to illustrate +four different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel foundry +work, and one of these for the Siemens-Martin process is illustrated by +Fig. 1. These ladles are made in sizes to take from five to fifteen ton +charges, or larger if required, and are mounted on a very strong +carriage with a backward and forward traversing motion, and tipping gear +for the ladle. The ladles are butt jointed, with internal cover strips, +and have a very strong band shrunk on hot about half way in the depth of +the ladle. This forms an abutment for supporting the ladle in the +gudgeon band, being secured to this last by latch bolts and cotters. The +gearing is made of cast steel, and there is a platform at one end for +the person operating the carriage or tipping the ladle. Stopper gear and +a handle are fitted to the ladles to regulate the flow of the molten +steel from the nozzle at the bottom. + +[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.] + +Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It +requires no description. Fig. 3 shows a tremendous ladle constructed for +the North-Eastern Steel Company, for carrying molten metal from the +blast furnace to the converter. It holds ten tons with ease. It is an +exceptionally strong structure. The carriage frame is constructed +throughout of 1 in. wrought-iron plated, and is made to suit the +ordinary 4 ft. 8½ in. railway gauge. The axle boxes are cast iron, +fitted with gun-metal steps. The wheels are made of forged iron, with +steel tires and axles. The carriage is provided with strong oak buffers, +planks, and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of ½ in. wrought-iron +plates, butt jointed, and double riveted butt straps. The trunnions and +flange couplings are of cast steel. The tipping gear, clearly shown in +the engraving, consists of a worm and wheel, both of steel, which can be +fixed on either side of the ladle as may be desired. From this it will +be seen that Messrs. Stevenson & Co. have made a thoroughly strong +structure in every respect, and one, therefore, that will commend itself +to most steel makers. We understand that these carriages are made in +various designs and sizes to meet special requirements. Thus, Fig. 4 +shows one of different design, made for a steel works in the North. This +is also a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great care +and honesty of purpose is required in making these structures. A +breakdown might any moment pour ten tons of molten metal on the ground, +with the most horrible results. + + * * * * * + + + + +APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE +SURFACE OF CONDUCTORS. + + +Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and +ingenious apparatus which permits of demonstrating that electricity +develops only on the surface of conductors. It consists (see figure) +essentially of a yellow-metal disk, M, fixed to an insulating support, +F, and carrying a concentric disk of ebonite, H. This latter receives a +hollow and closed hemisphere, J, of yellow metal, whose base has a +smaller diameter than that of the disk, H, and is perfectly insulated by +the latter. Another yellow-metal hemisphere, S, open below, is connected +with an insulating handle, G. The basal diameter of this second +hemisphere is such that when the latter is placed over J its edge rests +upon the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a hollow, +closed hemisphere that imprisons the hemisphere, J, which is likewise +hollow and closed, and perfectly insulated from the former. + +[Illustration] + +The shell, S, is provided internally with a curved yellow-metal spring, +whose point of attachment is at B, and whose free extremity is connected +with an ebonite button, K, which projects from the shell, S. By pressing +this button, a contact may be established between the external +hemisphere (formed of the pieces, S and M), and the internal one, J. As +soon as the button is left to itself, the spring again begins to bear +against the interior surface of S, and the two hemispheres are again +insulated. + +The experiment is performed in this wise: The shell, S, is removed. Then +a disk of steatite affixed to an insulating handle is rubbed for a few +instants with a fox's "brush," and held near J until a spark occurs. +Then the apparatus is grasped by the support, F, and an elder-pith ball +suspended by a flaxen thread from a good conducting support is brought +near J. The ball will be quickly repelled, and care must be taken that +it does not come into contact with J. After this the apparatus is placed +upon a table, the shell, S, is taken by its handle, G, and placed in the +position shown in the figure, and a momentary contact is established +between the two hemispheres by pressing the button, K. Then the shell, +S, is lifted, and the disk, M, is touched at the same time with the +other hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, thus +proving that all the electricity passed from J to S at the moment of +contact.--_La Lumiere Electrique_. + + * * * * * + + + + +THE COLSON TELEPHONE. + + +This apparatus has recently been the object of some experiments which +resulted in its being finally adopted in the army. We think that our +readers will read a description of it with interest. Its mode of +construction is based upon a theoretic conception of the lines of force, +which its inventor explains as follows in his Elementary Treatise on +Electricity: + +"To every position of the disk of a magnetic telephone with respect to +the poles of the magnet there corresponds a certain distribution of the +lines of force, which latter shift themselves when the disk is +vibrating. If the bobbin be met by these lines in motion, there will +develop in its wire a difference of potential that, according to +Faraday's law, will be proportional to their number. All things equal, +then, a telephone transmitter will be so much the more potent in +proportion as the lines set in motion by the vibrations of the disk and +meeting the bobbin wire are greater in number. In like manner, a +receiver will be so much the more potent in proportion as the lines of +force, set in motion by variations in the induced currents that are +traversing the bobbin and meeting the disk, are more numerous. It will +consequently be seen that, generally speaking, it is well to send as +large a number of lines of force as possible through the bobbin." + +[Illustration: FIG. 1.--THE COLSON TELEPHONE.] + +In order to obtain such a result, the thin tin-plate disk has to be +placed between the two poles of the magnet. The pole that carries the +fine wire bobbin acts at one side and in the center of the disk, while +the other is expanded at the extremity and acts upon the edge and the +other side. This pole is separated from the disk by a copper washer, and +the disk is thus wholly immersed in the magnetic field, and is traversed +by the lines of force radiatingly. + +This telephone is being constructed by Mr. De Branville, with the +greatest care, in the form of a transmitter (Fig. 2) and receiver (Fig. +3). At A may be seen the magnet with its central pole, P, and its +eccentric one, P'. This latter traverses the vibrating disk, M, through +a rubber-lined aperture and connects with the soft iron ring, F, that +forms the polar expansion. These pieces are inclosed in a nickelized +copper box provided with a screw cap, C. The resistance of both the +receiver and transmitter bobbin is 200 ohms. + +[Illustration: FIG. 2.--TRANSMITTER TAKEN APART.] + +The transmitter is 3½ in. in diameter, and is provided with a +re-enforcing mouthpiece. It is regulated by means of a screw which is +fixed in the bottom of the box, and which permits of varying the +distance between the disk and the core that forms the central pole of +the magnet. The regulation, when once effected, lasts indefinitely. The +regulation of the receiver, which is but 2¼ in. in diameter, is +performed once for all by the manufacturer. One of the advantages of +this telephone is that its regulation is permanent. Besides this, it +possesses remarkable power and clearness, and is accompanied with no +snuffling sounds, a fact doubtless owing to all the molecules of the +disk being immersed in the magnetic field, and to the actions of the two +poles occurring concentrically with the disk. As we have above said, +this apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used by +the artillery service in the organization of observatories from which to +watch firing, and the receiver is added to the apparatus pertaining to +military telegraphy. The two small receivers are held to the lens of the +operator by the latter's hat strap, while the transmitter is suspended +in a case supported by straps, with the mouthpieces near the face (Fig. +1). + +In the figure, the case is represented as open, so as to show the +transmitter. The empty compartment below is designed for the reception +and carriage of the receivers, straps, and flexible cords. This +arrangement permits of calling without the aid of special apparatus, and +it has also the advantage of giving entire freedom to the man on +observation, this being something that is indispensable in a large +number of cases. + +[Illustration: FIG. 3.--RECEIVER TAKEN APART.] + +In certain applications, of course, the receivers may be combined with a +microphone; yet on an aerial as well as on a subterranean line the +transmitter produces effects which, as regards intensity and clearness, +are comparable with those of a pile transmitter. + +Stations wholly magnetic may be established by adding to the transmitter +and two receivers a Sieur phonic call, which will actuate them +powerfully, and cause them to produce a noise loud enough for a call. It +would be interesting to try this telephone on a city line, and to a +great distance on those telegraph lines that are provided with the Van +Rysselberghe system. Excellent results would certainly be obtained, for, +as we have recently been enabled to ascertain, the voice has a +remarkable intensity in this telephone, while at the same time perfectly +preserving its quality.--_La Nature_. + + * * * * * + +[NATURE.] + + + + +THE MELDOMETER. + + +The apparatus which I propose to call by the above name +([mu][epsilon][lambda][delta][omega], to melt) consists of an adjunct to +the mineralogical microscope, whereby the melting-points of minerals may +be compared or approximately determined and their behavior watched at +high temperatures either alone or in the presence of reagents. + +As I now use it, it consists of a narrow ribbon of platinum (2 mm. wide) +arranged to traverse the field of the microscope. The ribbon, clamped in +two brass clamps so as to be readily renewable, passes bridgewise over a +little scooped-out hollow in a disk of ebony (4 cm. diam.). The clamps +also take wires from a battery (3 Groves cells); and an adjustable +resistance being placed in circuit, the strip can be thus raised in +temperature up to the melting-point of platinum. + +The disk being placed on the stage of the microscope the platinum strip +is brought into the field of a 1" objective, protected by a glass slip +from the radiant heat. The observer is sheltered from the intense light +at high temperatures by a wedge of tinted glass, which further can be +used in photometrically estimating the temperature by using it to obtain +extinction of the field. Once for all approximate estimations of the +temperature of the field might be made in terms of the resistance of the +platinum strip, the variation of such resistance with rise of +temperature being known. Such observations being made on a suitably +protected strip might be compared with the wedge readings, the latter +being then used for ready determinations. Want of time has hindered me +from making such observations up to this. + +The mineral to be experimented on is placed in small fragments near the +center of the platinum ribbon, and closely watched while the current is +increased, till the melting-point of the substance is apparent. Up to +the present I have only used it comparatively, laying fragments of +different fusibilities near the specimen. In this way I have melted +beryl, orthoclase, and quartz. I was much surprised to find the last +mineral melt below the melting-point of platinum. I have, however, by me +as I write, a fragment, formerly clear rock-crystal, so completely fused +that between crossed Nicols it behaves as if an amorphous body, save in +the very center where a speck of flashing color reveals the remains of +molecular symmetry. Bubbles have formed in the surrounding glass. + +Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way. + +Topaz whitens to a milky glass--apparently decomposing, throwing out +filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot platinum, +causes rings of color to appear round the specimen. I have now been +using the apparatus for nearly a month, and in its earliest days it led +me right in the diagnosis of a microscopical mineral, iolite, not before +found in our Irish granite, I think. The unlooked-for characters of the +mineral, coupled with the extreme minuteness of the crystals, led me +previously astray, until my meldometer fixed its fusibility for me as +far above the suspected bodies. + +Carbon slips were at first used, as I was unaware of the capabilities of +platinum. + +A form of the apparatus adapted, at Prof. Fitzgerald's suggestion, to +fit into the lantern for projection on the screen has been made for me +by Yeates. In this form the heated conductor passes both below and above +the specimen, which is regarded from a horizontal direction. + +J. JOLY. + +Physical Laboratory, Trinity College, Dublin. + + * * * * * + +[AMERICAN ANNALS OF THE DEAF AND DUMB.] + + + + +TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF DEAF-MUTES. + + +Progress in electrical science is daily causing the world to open its +eyes in wonder and the scientist to enlarge his hopes for yet greater +achievements. The practical uses to which this subtile fluid, +electricity, is being put are causing changes to be made in time-tested +methods of doing things in domestic, scientific, and business circles, +and the time has passed when startling propositions to accomplish this +or that by the assistance of electricity are dismissed with incredulous +smiles. This being the case, no surprise need follow the announcement of +a device to facilitate the imparting of instruction to deaf children +which calls into requisition some service from electricity. + +The sense of touch is the direct medium contemplated, and it is intended +to convey, with accuracy and rapidity, messages from the operator (the +teacher) to the whole class simultaneously by electrical +transmission.[1] + +[Footnote 1: By the same means two deaf-mutes, miles apart, might +converse with each other, and the greatest difficulty in the way of a +deaf-mute becoming a telegraph operator, that of receiving messages, +would be removed. The latter possibilities are incidentally mentioned +merely as of scientific interest, and not because of their immediate +practical value. The first mentioned use to which the device may be +applied is the one considered by the writer as possibly of practical +value, the consideration of which suggested the appliance to him.] + +An alphabet is formed upon the palm of the left hand and the inner side +of the fingers, as shown by the accompanying cut, which, to those +becoming familiar with it, requires but a touch upon a certain point of +the hand to indicate a certain letter of the alphabet. + +A rapid succession of touches upon various points of the hand is all +that is necessary in spelling a sentence. The left hand is the one upon +which the imaginary alphabet is formed, merely to leave the right hand +free to operate without change of position when two persons only are +conversing face to face. + +The formation of the alphabet here figured is on the same principle as +one invented by George Dalgarno, a Scottish schoolmaster, in the year +1680, a cut of which maybe seen on page 19 of vol. ix. of the _Annals_, +accompanying the reprint of a work entitled "_Didascalocophus_." +Dalgarno's idea could only have been an alphabet to be used in +conversation between two persons _tête à tête_, and--except to a limited +extent in the Horace Mann School and in Professor Bell's teaching--has +not come into service in the instruction of deaf-mutes or as a means of +conversation. There seems to have been no special design or system in +the arrangement of the alphabet into groups of letters oftenest +appearing together, and in several instances the proximity would +seriously interfere with distinct spelling; for instance, the group "u," +"y," "g," is formed upon the extreme joint of the little finger. The +slight discoverable system that seems to attach to his arrangement of +the letters is the placing of the vowels in order upon the points of the +fingers successively, beginning with the thumb, intended, as we suppose, +to be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly as +another. If any arrangement has advantage over another, we consider it +the one which has so grouped the letters as to admit of an increased +rapidity of manipulation. The arrangement of the above alphabet, it is +believed, does admit of this. Yet it is not claimed that it is as +perfect as the test of actual use may yet make it. Improvements in the +arrangement will, doubtless, suggest themselves, when the alterations +can be made with little need of affecting the principle. + +In order to transmit a message by this alphabet, the following described +appliance is suggested: A matrix of cast iron, or made of any suitable +material, into which the person receiving the message (the pupil) places +his left hand, palm down, is fixed to the table or desk. The matrix, +fitting the hand, has twenty-six holes in it, corresponding in position +to the points upon the hand assigned to the different letters of the +alphabet. In these holes are small styles, or sharp points, which are so +placed as but slightly to touch the hand. Connected with each style is a +short line of wire, the other end of which is connected with a principal +wire leading to the desk of the operator (the teacher), and there so +arranged as to admit of opening and closing the circuit of an electric +current at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric impulses, +intended to act mechanically upon all the styles connected with it. By +these impulses, produced by the will of the sender, the styles are +driven upward with a quick motion, but with only sufficient force to be +felt and located upon the hand by the recipient. Twenty-six of these +principal or primary wires are run from the teacher's desk (there +connected with as many buttons) under the floor along the line of +pupils' desks. From each matrix upon the desk run twenty-six secondary +wires down to and severally connecting with the twenty-six primary wires +under the floor. The whole system of wires is incased so as to be out of +sight and possibility of contact with foreign substances. The keys or +buttons upon the desk of the teacher are systematically arranged, +somewhat after the order of those of the type writer, which allows the +use of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," "c," +etc., to "z," and an electric current over the primary wire running from +a certain button (say the one labeled "a") affects only those secondary +wires connected with the styles that, when excited, produce upon the +particular spot of the hands of the receivers the tactile impression to +be interpreted as "a." And so, whenever the sender touches any of the +buttons on his desk, immediately each member of the class feels upon the +palm of his hand the impression meant to be conveyed. The contrivance +will admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric bell. +It was first thought of conveying the impressions directly by slight +electric shocks, without the intervention of further mechanical +apparatus, but owing to a doubt as to the physical effect that might be +produced upon the persons receiving, and as to whether the nerves might +not in time become partly paralyzed or so inured to the effect as to +require a stronger and stronger current, that idea was abandoned, and +the one described adopted. A diagram of the apparatus was submitted to a +skillful electrical engineer and machinist of Hartford, who gave as his +opinion that the scheme was entirely feasible, and that a simple and +comparatively inexpensive mechanism would produce the desired result. + +[Illustration: TOUCH TRANSMISSION BY ELECTRICITY.] + +The matter now to consider, and the one of greater interest to the +teacher of deaf children, is, Of what utility can the device be in the +instruction of deaf-mutes? What advantage is there, not found in the +prevailing methods of communication with the deaf, i.e., by gestures, +dactylology, speech and speech-reading, and writing? + +I. The language of gestures, first systematized and applied to the +conveying of ideas to the deaf by the Abbe de l'Epee during the latter +part of the last century, has been, in America, so developed and +improved upon by Gallaudet, Peet, and their successors, as to leave but +little else to be desired for the purpose for which it was intended. The +rapidity and ease with which ideas can be expressed and understood by +this "language" will never cease to be interesting and wonderful, and +its value to the deaf can never fail of being appreciated by those +familiar with it. But the genius of the language of signs is such as to +be in itself of very little, if any, direct assistance in the +acquisition of syntactical language, owing to the diversity in the order +of construction existing between the English language and the language +of signs. Sundry attempts have been made to enforce upon the +sign-language conformity to the English order, but they have, in all +cases known to the writer, been attended with failure. The sign-language +is as immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given with +great success upon the basis of the sign-language. But in all such +exercises there must be a translation from one language to the other. +The desideratum still exists of an increased percentage of pupils +leaving our schools for the deaf, possessing a facility of expression in +English vernacular. This want has been long felt, and endeavoring to +find a reason for the confessedly low percentage, the sign-language has +been too often unjustly accused. It is only when the sign-language is +abused that its merit as a means of instruction degenerates. The most +ardent admirers of a proper use of signs are free to admit that any +excessive use by the pupils, which takes away all opportunities to +express themselves in English, is detrimental to rapid progress in +English expression. + +II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as one +of the elements of the American or eclectic method. This advantage, +however, is not of so great importance as to outweigh the disadvantages +when, as has honestly been attempted, it asserts its independence of +other methods. Very few persons indeed, even after long practice, become +sufficiently skillful in spelling on the fingers to approximate the +rapidity of speech. But were it possible for all to become rapid +spellers, another very important requisite is necessary before the +system could be a perfect one, that is, the ability to _read_ rapid +spelling. The number of persons capable of reading the fingers beyond a +moderate degree of rapidity is still less than the number able to spell +rapidly. While it is physically possible to follow rapid spelling for +twenty or thirty minutes, it can scarcely be followed longer than that. +So long as this is true, dactylology can hardly claim to be more than +one of the _elements_ of a system of instruction for the deaf. + +III. Articulate speech is another of the elements of the eclectic +method, employed with success inversely commensurate with the degree of +deficiency arising from deafness. Where the English order is already +fixed in his mind, and he has at an early period of life habitually used +it, there is comparatively little difficulty in instructing the deaf +child by speech, especially if he have a quick eye and bright intellect. +But the number so favored is a small percentage of the great body of +deaf-mutes whom we are called upon to educate. When it is used as a +_sole_ means of educating the deaf as a class its inability to stand +alone is as painfully evident as that of any of the other component +parts of the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to what +a word is if spelled slowly enough, and if its meaning has been learned. +This cannot be said of speech. Between many words there is not, when +uttered, the slightest visible distinction. Between a greater number of +others the distinction is so slight as to cause an exceedingly nervous +hesitation before a guess can be given. Too great an imposition is put +upon the eye to expect it to follow unaided the extremely circumscribed +gestures of the organs of speech visible in ordinary speaking. The ear +is perfection as an interpreter of speech to the brain. It cannot +correctly be said that it is _more_ than perfection. It is known that +the ear, in the interpretation of vocal sounds, is capable of +distinguishing as many as thirty-five sounds per second (and oftentimes +more), and to follow a speaker speaking at the rate of more than two +hundred words per minute. If this be perfection, can we expect the _eye_ +of ordinary mortal to reach it? Is there wonder that the task is a +discouraging one for the deaf child? + +But it has been asserted that while a large percentage (practically all) +of the deaf _can_, by a great amount of painstaking and practice, become +speech readers in some small degree, a relative degree of facility in +articulation is not nearly so attainable. As to the accuracy of this +view, the writer cannot venture an opinion. Judging from the average +congenital deaf-mute who has had special instruction in speech, it can +safely be asserted that their speech is laborious, and far, very far, +from being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that as an +unaided means of instruction it cannot be a success, for English neither +understood when spoken, nor spoken by the pupil, cannot but remain a +foreign language, requiring to pass through some other form of +translation before it becomes intelligible. + +There are the same obstacles in the use of the written or printed word +as have been mentioned in connection with dactylology, namely, lack of +rapidity in conveying impressions through the medium of the English +sentence. + +I have thus hastily reviewed the several means which teachers generally +are employing to impart the use of English to deaf pupils, for the +purpose of showing a common difficulty. The many virtues of each have +been left unnoticed, as of no pertinence to this article. + +The device suggested at the beginning of this paper, claiming to be +nothing more than a school room appliance intended to supplement the +existing means for giving a knowledge and practice of English to the +deaf, employs as its interpreter a different sense from the one +universally used. The sense of sight is the sole dependence of the deaf +child. Signs, dactylology, speech reading, and the written and printed +word are all dependent upon the eye for their value as educational +instruments. It is evident that of the two senses, sight and touch, if +but one could be employed, the choice of sight as the one best adapted +for the greatest number of purposes is an intelligent one; but, as the +choice is not limited, the question arises whether, in recognizing the +superior adaptability to our purpose of the one, we do not lose sight of +a possibly important, though secondary, function in the other. If sight +were all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we acquire +our vernacular is of divine, and not of human, origin, and the senses +designed for special purposes are not interchangeable without loss. The +theory that the loss of a certain sense is nearly, if not quite, +compensated for by increased acuteness of the remaining ones has been +exploded. Such a theory accuses, in substance, the Maker of creating +something needless, and is repugnant to the conceptions we have of the +Supreme Being. When one sense is absent, the remaining senses, in order +to equalize the loss, have imposed upon them an unusual amount of +activity, from which arises skill and dexterity, and by which the loss +of the other sense is in some measure alleviated, but not supplied. No +_additional_ power is given to the eye after the loss of the sense of +hearing other than it might have acquired with the same amount of +practice while both faculties were active. The fact, however, that the +senses, in performing their proper functions, are not overtaxed, and are +therefore, in cases of emergency, capable of being extended so as to +perform, in various degrees, additional service, is one of the wise +providences of God, and to this fact is due the possibility of whatever +of success is attained in the work of educating the deaf, as well as the +blind. + +In the case of the blind, the sense of touch is called into increased +activity by the absence of the lost sense; while in the case of the +deaf, sight is asked to do this additional service. A blind person's +education is received principally through the _two_ senses of hearing +and touch. Neither of these faculties is so sensible to fatigue by +excessive use as is the sense of sight, and yet the eye has, in every +system of instruction applied to the deaf, been the sole medium. In no +case known to the writer, excepting in the celebrated case of Laura +Bridgman and a few others laboring under the double affliction of +deafness and blindness, has the sense of touch been employed as a means +of instruction.[1] + +[Footnote 1: This article was written before Professor Bell had made his +interesting experiments with his "parents' class" of a touch alphabet, +to be used upon the pupil's shoulder in connection with the oral +teaching.--E.A.F.] + +Not taking into account the large percentage of myopes among the deaf, +we believe there are other cogent reasons why, if found practicable, the +use of the sense of touch may become an important element in our +eclectic system of teaching. We should reckon it of considerable +importance if it were ascertained that a portion of the same work now +performed by the eye could be accomplished equally as well through +feeling, thereby relieving the eye of some of its onerous duties. + +We see no good reason why such accomplishment may not be wrought. If, +perchance, it were discovered that a certain portion could be performed +in a more efficient manner, its value would thus be further enhanced. + +In theory and practice, the teacher of language to the deaf, by whatever +method, endeavors to present to the eye of the child as many completed +sentences as are nominally addressed to the ear--having them "caught" by +the eye and reproduced with as frequent recurrence as is ordinarily done +by the child of normal faculties. + +In our hasty review of the methods now in use we noted the inability to +approximate this desirable process as a common difficulty. The facility +now ordinarily attained in the manipulation of the type writer, and the +speed said to have been reached by Professor Bell and a private pupil of +his by the Dalgarno touch alphabet, when we consider the possibility of +a less complex mechanism in the one case and a more systematic grouping +of the alphabet in the other, would lead us to expect a more rapid means +of communication than is ordinarily acquired by dactylology, speech (by +the deaf), or writing. Then the ability to receive the communication +rapidly by the sense of feeling will be far greater. No part of the body +except the point of the tongue is as sensible to touch as the tips of +the fingers and the palm of the hand. Tactile discrimination is so acute +as to be able to interpret to the brain significant impressions produced +in very rapid succession. Added to this advantage is the greater one of +the absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the tympanum of +the ear. To sum up, then, the advantages of the device we find-- + +First. A more rapid means of communication with the deaf by syntactic +language, admitting of a greater amount of practice similar to that +received through the ear by normal children. + +Second. Ability to receive this rapid communication for a longer +duration and without ocular strain. + +Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender. + +Fourth. In articulation and speech-reading instruction, the power to +assist a class without distracting the attention of the eye from the +vocal organs of the teacher. + +Fifth. Freedom of the right hand of the pupil to make instantaneous +reproduction in writing of the matter being received through the sense +of feeling, thereby opening the way for a valuable class exercise. + +Sixth. The possible mental stimulus that accompanies the mastery of a +new language, and the consequent ability to receive known ideas through +a new medium. + +Seventh. A fresh variety of class exercises made possible. + +The writer firmly believes in the good that exists in all methods that +are, or are to be; in the interdependence rather than the independence +of all methods; and in all school-room appliances tending to supplement +or expedite the labors of the teacher, whether they are made of +materials delved from the earth or snatched from the clouds. + +S. TEFFT WALKER, + +_Superintendent of the Kansas Institution, Olathe, Kans_. + + * * * * * + + + + +WATER GAS. + +THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON REDUCING AGENTS. + +By B.H. THWAITE. + + +In order to approximately ascertain the relative reducing action of +water gas, carbon monoxide, and superheated steam on iron ore, the +author decided to have carried out the following experiments, which were +conducted by Mr. Carl J. Sandahl, of Stockholm, who also carried out the +analyses. The ore used was from Bilbao, and known as the Ruby Mine, and +was a good average hematite. The carbonaceous material was the Trimsaran +South Wales anthracite, and contained about 90 per cent. of carbon. + +A small experimental furnace was constructed of the form shown by +illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the base, +and gradually swelling to 2 ft. 9 in. at the top, built entirely of +fireclay bricks. Two refractory tubes, 2 in. square internally, and the +height of the furnace, were used for the double purpose of producing the +gas and reducing the ore. + +The end of the lower tube rested on a fireclay ladle nozzle, and was +properly jointed with fireclay; through this nozzle the steam or air was +supplied to the inside of the refractory tubes. In each experiment the +ore and fuel were raised to the temperature "of from 1,800 to 2,200 deg. +Fahr." by means of an external fire of anthracite. Great care was taken +to prevent the contact of the solid carbonaceous fuel with the ore. In +each experiment in which steam was used, the latter was supplied at a +temperature equivalent to 35 lb. to the square inch. + +The air for producing the carbon monoxide (CO) gas was used at the +temperature of the atmosphere. As near as possible, the same conditions +were obtained in each experiment, and the equivalent weight of air was +sent through the carbon to generate the same weight of CO as that +generated when steam was used for the production of water gas. + +[Illustration] + +_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled +with ore broken to the size of nuts. The tube, A, was heated to about +2,000 deg. Fahr., the upper one to about 1,500 deg. + +NOTE.--In this experiment, part of the steam was dissociated in passing +through the turned-up end of the steam supply pipe, which became very +hot, and the steam would form with the iron the magnetic oxide +(Fe_{3}O_{4}). The reduction would doubtless be due to this +dissociation. The pieces of ore found on lowest end of the tube, A, were +dark colored and semi-fused; part of one of these pieces was crushed +fine, and tested; see column I. The remainder of these black pieces was +mixed with the rest of the ore contained in tube, A, and ground and +tested; see column II. The ore in upper tube was all broken up together +and tested; see column III. When finely crushed, the color of No. I. was +bluish black; No. II., a shade darker red; No. III., a little darker +than the natural color of the ore. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- + +_Second Experiment, Water Gas_.--The tube, A, was filled with small +pieces of anthracite, and heated until all the volatile matter had been +expelled. The tube, B, was then placed in tube, A, the joint being made +with fireclay, and to prevent the steam from carrying small particles of +solid carbon into ore in the upper tube, the anthracite was divided from +the ore by means of a piece of fine wire gauze. The steam at a pressure +of about 35 lb. to the square inch was passed through the anthracite. +The tube, A, was heated to white heat, the tube, B, at its lower end to +bright red, the top to cherry red. + +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ + +_Four Samples were Tested_.--I. The bottom layer, 1¼ in. thick; the +color of ore quite black, with small particles of reduced spongy +metallic iron. II. Layer above I., 4¼ in. thick; the color was also +black, but showed a little purple tint. III. Layer above II., 5 in. +thick; purple red color. IV. Layer above III., ore a red color. The +analyses gave: + +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- + +NOTE.--All the carbon dioxide (CO_{2}) occurring in the ore as calcic +carbonate was expelled. + +_Third Experiment, Carbon monoxide_ (CO).--The tube A was filled with +anthracite in the manner described for the second experiment, and heated +to drive off the volatile matter, before the ore was placed in the upper +tube, B, and the anthracite was divided from the ore by means of a piece +of fine wire gauze. The lower tube, A, was heated to the temperature of +white heat, the upper one, B, to a temperature of bright red. I. Layer, +1 in. thick from the bottom; ore dark brownish colored. II. Layer 4 in. +thick above I.; ore reddish brown. III. Layer 11 in. thick above II.; +ore red color. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- + +NOTE.--The carbon monoxide (CO) had failed to remove from the ore the +carbon dioxide existing as calcic carbonate. The summary of experiments +in the following table appears to show that the water gas is a more +powerful reducing agent than CO in proportion to the ratio of as + + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 + +Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just now +constructing large experimental plant in which water gas will be used as +the reducing agent. This plant would have been at work before this but +for some defects in the valvular arrangements, which will be entirely +removed in the new modifications of the plant. + + * * * * * + + + + +ANTISEPTIC MOUTH WASH. + + +Where an antiseptic mouth wash is needed, Mr. Sewill prescribes the use +of perchloride of mercury in the following form: One grain of the +perchloride and 1 grain of chloride of ammonium to be dissolved in 1 oz. +of eau de Cologne or tincture of lemons, and a teaspoonful of the +solution to be mixed with two-thirds of a wineglassful of water, making +a proportion of about 1 of perchloride in 5,000 parts.--_Chemist and +Druggist_. + + * * * * * + + + + +ANNATTO. + +[Footnote: Read at an evening meeting of the North British Branch of the +Pharmaceutical Society, January 21.] + +By WILLIAM LAWSON. + + +The subject which I have the honor to bring shortly before your notice +this evening is one that formed the basis of some instructive remarks by +Dr. Redwood in November, 1855, and also of a paper by Dr. Hassall, read +before the Society in London in January, 1856, which latter gave rise to +an animated discussion. The work detailed below was well in hand when +Mr. MacEwan drew my attention to these and kindly supplied me with the +volume containing reports of them. Unfortunately, they deal principally +with the adulterations, while I was more particularly desirous to learn +the composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. Within +the last few years it was one of the articles in considerable demand in +this part of the country; now it is seldom inquired for. This, +certainly, is not because butter coloring has ceased to be employed, and +hence the reason for regretting that the percentage of resin was not +dealt with in the articles referred to, so that a comparison could have +been made between the commercial annatto of that period and that which +exists now. In case some may not be in possession of literature bearing +on it--which, by the way, is very meager--it may not be out of place to +quote some short details as to its source, the processes for obtaining +it, the composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has more +interest for the country than for the town druggist, still, I trust it +will have points of interest for both. + +Annatto is the coloring matter derived from the seeds of an evergreen +plant, _Bixa Orellana_, which grows in the East and West Indian Islands +and South America, in the latter of which it is principally prepared. +Two kinds are imported, Spanish annatto, made in Brazil, and flag or +French, made mostly in Cayenne. These differ considerably in characters +and properties, the latter having a disagreeable putrescent odor, while +the Spanish is rather agreeable when fresh and good. It is, however, +inferior to the flag as a coloring or dyeing agent. The seeds from which +the substance is obtained are red on the outside, and two methods are +followed in order to obtain it. One is to rub or wash off the coloring +matter with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to bruise +the seeds, mix them with water, and allow fermentation to set in, during +which the coloring matter collects at the bottom, from which it is +subsequently removed and brought to the proper consistence by +spontaneous evaporation. These particulars, culled from Dr. Redwood's +remarks, may suffice to show its source and the methods for obtaining +it. + +Dr. John gives the following as the composition of the pulp surrounding +the seeds: Coloring resinous matter, 28; vegetable gluten, 26.5; +ligneous fiber, 20; coloring, 20; extractive matter, 4; and a trace of +spicy and acid matter. + +It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as well as +to preserve it, differs considerably from this; and though it may not be +true, as some hint, that manufacturing in this industry is simply a term +synonymous with adulterating, yet results will afterward be given +tending to show that there are articles in the market which have little +real claim to the title. I tried, but failed, to procure a sample of raw +material on which to work, with a view to learn something of its +characters and properties in this state, and thus be able to contrast it +with the manufactured or commercial article. The best thing to do in the +circumstances, I thought, was to operate on the highest priced sample at +disposal, and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the usual +way, I believe--was a more troublesome operation than it appeared to be, +as the following experiment will show: One hundred grains of No. 8 were +taken, dried thoroughly, reduced to fine powder, and introduced into a +flask containing 4 ounces of alcohol in the form of methylated spirit, +boiled for an hour--the flask during the operation being attached to an +inverted condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated with +diminishing quantities until in all 14 ounces had been used before the +alcoholic solution ceased to turn blue on the addition to it of strong +sulphuric acid, or failed to give a brownish precipitate with stannous +chloride. As the sample contained a considerable quantity of potassium +carbonate, in which the resin is soluble, it was thought that by +neutralizing this it might render the resin more easy of extraction. +This was found to be so, but it was accompanied by such a mass of +extractive as made it in the long run more troublesome, and hence it was +abandoned. Thinking the spirit employed might be too weak, an experiment +with commercial absolute alcohol was carried out as follows: One hundred +grains of a red sample, No. 4, were thoroughly dried, powdered finely, +and boiled in 2 ounces of the alcohol, filtered, and the residue treated +with half an ounce more. This required to be repeated with fresh half +ounces of the alcohol until in all 7½ were used; the time occupied from +first to last being almost three hours. This was considered +unsatisfactory, besides being very expensive, and so it, also, was set +aside, and a series of experiments with methylated spirit alone was set +in hand. The results showed that the easiest and most satisfactory way +was to take 100 grains (this amount being preferred, as it reduces error +to the minimum), dry thoroughly, powder finely, and macerate with +frequent agitation for twenty-four hours in a few ounces of spirit, then +to boil in this spirit for a short time, filter, and repeat the boiling +with a fresh ounce or so; this, as a rule, sufficing to completely +exhaust it of its resin. Wynter Blyth says that the red resin, or bixin, +is soluble in 25 parts of hot alcohol. It appears from these experiments +that much more is required to dissolve it out of commercial annatto. + +The full process followed consisted in determining the moisture by +drying 100 grains at 212° F. till constant, and taking this dried +portion for estimation of the resin in the way just stated. The +alcoholic extract was evaporated to dryness over a water-bath, the +residue dissolved in solution of sodium carbonate, and the resin +precipitated by dilute sulphuric acid (these reagents being chosen as +the best after numerous trials with others), added in the slightest +possible excess. The resin was collected on a tared double filter paper, +washed with distilled water until the washings were entirely colorless, +dried and weighed. + +The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of them. + +The results are as follows: + + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 + +The first six are the ordinary red rolls, with the exception of No. 4, +which is a red mass, the only one of this class direct from the +manufacturers. The remainder are brown cakes, all except No. 7 being +from the manufacturers direct. The ash of the first two was largely +common salt; that of No. 3 contained, besides this, iron in some +quantity. No. 4 is unique in many respects. It was of a bright red +color, and possessed a not disagreeable odor. It contained the largest +percentage of moisture and the lowest of ash; had, comparatively, a +large amount of coloring matter; was one of the cheapest, and in the +course of some dairy trials, carried out by an intelligent farmer, was +pronounced to be the best suited for coloring butter. So far as my +experience goes, it was a sample of the best commercial excellence, +though I fear the mass of water present and the absence of preserving +substances will assist in its speedy decay. Were such an article easily +procured in the usual way of business, there would not be much to +complain of, but it must not be forgotten that it was got direct from +the manufacturers--a somewhat suggestive fact when the composition of +some other samples is taken into account. No. 5 emitted a disagreeable +odor during ignition. The soluble portion of the ash was mostly common +salt, and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter gave +rise to disagreeable reflections. It was wrapped in a paper saturated +with a strongly smelling linseed oil. When it was boiled in water and +broken up, hairs, among other things, were observed floating about. It +contained some iron. The first cake, No. 7, gave off during ignition an +agreeable odor resembling some of the finer tobaccos, and this is +characteristic more or less of all the cakes. The ash weighed 52 per +cent., the soluble part of which, 18.5, was mostly potassium carbonate, +with some chlorides and sulphates; the insoluble, mostly chalk with iron +and alumina. No. 8--highest priced of all--had in the mass an odor which +I can compare to nothing else than a well rotted farmyard manure. Twenty +parts of the ash were soluble and largely potassium carbonate, the +insoluble being iron for the most part. The mineral portions of Nos. 9 +and 10 closely resemble No. 7. + +On looking over the results, it is found that the red rolls contained +starchy matters in abundance (in No. 4 the starch was to a large extent +replaced by water), and an ash, mostly sodium chloride, introduced no +doubt to assist in its preservation as well as to increase the color of +the resin--a well known action of salt on vegetable reds. The cakes, +which are mostly used for cheese coloring, I believe, all appeared to +contain turmeric, for they gave a more or less distinct reaction with +the boric acid test, and all except No. 8 contained large quantities of +chalk. These results in reference to extractive, etc., reveal nothing +that has not been known before. Wynter Blyth, who gives the only +analyses of annatto I have been able to find, states that the +composition of a fair commercial sample (which I take to mean the raw +article) examined by him was as follows: water, 24.2; resin, 28.8; ash, +22.5; and extractive, 24.5; and that of an adulterated (which I take to +mean a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. 27.3. If +this be correct, it appears that the articles at present in the market, +or at least those which have come in my way, have been wretched +imitations of the genuine thing, and should, instead of being called +adulterated annatto, be called something else adulterated, but not +seriously, with annatto. I have it on the authority of the farmer +previously referred to, that ¼ of an ounce of No. 4 is amply sufficient +to impart the desired cowslip tint to no less than 60 lb. of butter. +When so little is actually required, it does not seem of very serious +importance whether the adulterant or preservative be flour, chalk, or +water, but it is exasperating in a very high degree to have such +compounds as Nos. 3 and 6 palmed off as decent things when even Nos. 1, +2, and 5 have been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may be +induced to examine the annatto taken into stock more closely than I was +taught to do, and had been in the habit of doing, namely, to see if it +had a good consistence and an odor resembling black sugar, for if so, +the quality was above suspicion. + + * * * * * + + + + +JAPANESE RICE WINE AND SOJA SAUCE. + + +Professor P. Cohn has recently described the mode in which he has +manufactured the Japanese sake or rice wine in the laboratory. The +material used was "Tane Kosi," i.e., grains of rice coated with the +mycelium, conidiophores, and greenish yellow chains of conidia of +_Aspergillus Oryzoe_. The fermentation is caused by the mycelium of this +fungus before the development of the fructification. The rice is first +exposed to moist air so as to change the starch into paste, and then +mixed with grains of the "Tane Kosi." The whole mass of rice becomes in +a short time permeated by the soft white shining mycelium, which imparts +to it the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two or +three days, and then subjected to alcoholic fermentation from the +_Saccharomyces_, which is always present in the rice, but which has +nothing to do with the _Aspergillus_. The fermentation is completed in +two or three weeks, and the golden yellow, sherry-like sake is poured +off. The sample manufactured contained 13.9 per cent. of alcohol. +Chemical investigation showed that the _Aspergillus_ mycelium transforms +the starch into glucose, and thus plays the part of a diastase. + +Another substance produced from the _Aspergillus_ rice is the soja +sauce. The soja leaves, which contain little starch, but a great deal of +oil and casein, are boiled, mixed with roasted barley, and then with the +greenish yellow conidia powder of the _Aspergillus_. After the mycelium +has fructified, the mass is treated with a solution of sodium chloride, +which kills the _Aspergillus_, another fungus, of the nature of a +_Chalaza_, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce then +separates. + + * * * * * + + + + +ALUMINUM. + +[Footnote: Annual address delivered by President J.A. Price before the +meeting of the Scranton Board of Trade, Monday, January 18, 1886.] + +By J.A. PRICE. + + +Iron is the basis of our civilization. Its supremacy and power it is +impossible to overestimate; it enters every avenue of development, and +it may be set down as the prime factor in the world's progress. Its +utility and its universality are hand in hand, whether in the +magnificent iron steamship of the ocean, the network of iron rail upon +land, the electric gossamer of the air, or in the most insignificant +articles of building, of clothing, and of convenience. Without it, we +should have miserably failed to reach our present exalted station, and +the earth would scarcely maintain its present population; it is indeed +the substance of substances. It is the Archimedean lever by which the +great human world has been raised. Should it for a moment forget its +cunning and lose its power, earthquake shocks or the wreck of matter +could not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that it +must give way to a metal that has still greater proportions and vaster +possibilities. Strange and startling as may seem the assertion, yet I +believe it nevertheless to be true that we are approaching the period, +if not already standing upon the threshold of the day, when this magical +element will be radically supplanted, and when this valuable mineral +will be as completely superseded as the stone of the aborigines. With +all its apparent potency, it has its evident weaknesses; moisture is +everywhere at war with it, gases and temperature destroy its fiber and +its life, continued blows or motion crystallize and rob it of its +strength, and acids will devour it in a night. If it be possible to +eliminate all, or even one or more, of these qualities of weakness in +any metal, still preserving both quantity and quality, that metal will +be the metal of the future. + +The coming metal, then, to which our reference is made is aluminum, the +most abundant metal in the earth's crust. Of all substances, oxygen is +the most abundant, constituting about one-half; after oxygen comes +silicon, constituting about one-fourth, with aluminum third in all the +list of substances of the composition. Leaving out of consideration the +constituents of the earth's center, whether they be molten or gaseous, +more or less dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we find +that aluminum is beyond question the most abundant and the most useful +of all metallic substances. + +It is the metallic base of mica, feldspar, slate, and clay. Professor +Dana says: "Nearly all the rocks except limestones and many sandstones +are literally ore-beds of the metal aluminum." It appears in the gem, +assuming a blue in the sapphire, green in the emerald, yellow in the +topaz, red in the ruby, brown in the emery, and so on to the white, +gray, blue, and black of the slates and clays. It has been dubbed "clay +metal" and "silver made from clay;" also when mixed with any +considerable quantity of carbon becoming a grayish or bluish black "alum +slate." + +This metal in color is white and next in luster to silver. It has never +been found in a pure state, but is known to exist in combination with +nearly two hundred different minerals. Corundum and pure emery are ores +that are very rich in aluminum, containing about fifty-four per cent. +The specific gravity is but two and one-half times that of water; it is +lighter than glass or as light as chalk, being only one-third the weight +of iron and one-fourth the weight of silver; it is as malleable as gold, +tenacious as iron, and harder than steel, being next the diamond. Thus +it is capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. Its +variety of transformations is something wonderful. Meeting iron, or even +iron at its best in the form of steel, in the same field, it easily +vanquishes it at every point. It melts at 1,300 degrees F., or at least +600 degrees below the melting point of iron, and it neither oxidizes in +the atmosphere nor tarnishes in contact with gases. The enumeration of +the properties of aluminum is as enchanting as the scenes of a fairy +tale. + +Before proceeding further with this new wonder of science, which is +already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French chemist +Lavoisier, a very magician in the science, groping in the dark of the +last century, evolved the chemical theory of combustion--the existence +of a "highly respirable gas," oxygen, and the presence of metallic bases +in earths and alkalies. With the latter subject we have only to do at +the present moment. The metallic base was predicted, yet not identified. +The French Revolution swept this genius from the earth in 1794, and +darkness closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon the +metallic base of certain earths, but the reflection was so feeble that +the great secret was never revealed. Then a little later the Swedish +Berzelius and the Danish Oersted, confident in the prediction of +Lavoisier and of Davy, went in search of the mysterious stranger with +the aggressive electric current, but as yet to no purpose. It was +reserved to the distinguished German Wohler, in 1827, to complete the +work of the past fifty years of struggle and finally produce the minute +white globule of the pure metal from a mixture of the chloride of +aluminum and sodium, and at last the secret is revealed--the first step +was taken. It took twenty years of labor to revolve the mere discovery +into the production of the aluminum bead in 1846, and yet with this +first step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come. + +Returning again to France some time during the years between 1854 and +1858, and under the patronage of the Emperor Napoleon III., we behold +Deville at last forcing Nature to yield and give up this precious +quality as a manufactured product. Rose, of Berlin, and Gerhard, in +England, pressing hard upon the heels of the Frenchman, make permanent +the new product in the market at thirty-two dollars per pound. The +despair of three-quarters of a century of toilsome pursuit has been +broken, and the future of the metal has been established. + +The art of obtaining the metal since the period under consideration has +progressed steadily by one process after another, constantly increasing +in powers of productivity and reducing the cost. These arts are +intensely interesting to the student, but must be denied more than a +reference at this time. The price of the metal may be said to have come +within the reach of the manufacturing arts already. + +A present glance at the uses and possibilities of this wonderful metal, +its application and its varying quality, may not be out of place. Its +alloys are very numerous and always satisfactory; with iron, producing a +comparative rust proof; with copper, the beautiful golden bronze, and so +on, embracing the entire list of articles of usefulness as well as works +of art, jewelry, and scientific instruments. + +Its capacity to resist oxidation or rust fits it most eminently for all +household and cooking utensils, while its color transforms the dark +visaged, disagreeable array of pots, pans, and kitchen implements into +things of comparative beauty. As a metal it surpasses copper, brass, and +tin in being tasteless and odorless, besides being stronger than either. + +It has, as we have seen, bulk without weight, and consequently may be +available in construction of furniture and house fittings, as well in +the multitudinous requirements of architecture. The building art will +experience a rapid and radical change when this material enters as a +component material, for there will be possibilities such as are now +undreamed of in the erection of homes, public buildings, memorial +structures, etc. etc., for in this metal we have the strength, +durability, and the color to give all the variety that genius may +dictate. + +And when we take a still further survey of the vast field that is +opening before us, we find in the strength without size a most desirable +assistant in all the avenues of locomotion. It is the ideal metal for +railway traffic, for carriages and wagons. The steamships of the ocean +of equal size will double their cargo and increase the speed of the +present greyhounds of the sea, making six days from shore to shore seem +indeed an old time calculation and accomplishment. A thinner as well as +a lighter plate; a smaller as well as a stronger engine; a larger as +well as a less hazardous propeller; and a natural condition of +resistance to the action of the elements; will make travel by water a +forcible rival to the speed attained upon land, and bring all the +distant countries in contact with our civilization, to the profit of +all. This metal is destined to annihilate space even beyond the dream of +philosopher or poet. + +The tensile strength of this material is something equally wonderful, +when wire drawn reaches as high as 128,000 pounds, and under other +conditions reaches nearly if not quite 100,000 pounds to the square +inch. The requirements of the British and German governments in the best +wrought steel guns reach only a standard of 70,000 pounds to the square +inch. Bridges may be constructed that shall be lighter than wooden ones +and of greater strength than wrought steel and entirely free from +corrosion. The time is not distant when the modern wonder of the +Brooklyn span will seem a toy. + +It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube. + +The resistance to corrosion evidently fits this metal for railway +sleepers to take the place of the decaying wooden ties. In this metal +the sleeper may be made as soft and yielding as lead, while the rail may +be harder and tougher than steel, thus at once forming the necessary +cushion and the avoidance of jar and noise, at the same time +contributing to additional security in virtue of a stronger rail. + +In conductivity this metal is only exceeded by copper, having many times +that of iron. Thus in telegraphy there are renewed prospects in the +supplanting of the galvanized iron wire--lightness, strength, and +durability. When applied to the generation of steam, this material will +enable us to carry higher pressure at a reduced cost and increased +safety, as this will be accomplished by the thinner plate, the greater +conductivity of heat, and the better fiber. + +It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in the +mechanic art lies dormant--the size of the machine may be reduced, the +speed and the power increased, realizing the conception of two things +better done than one before. It is one of man's creative acts. + +From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, Paris, +asserts that 120,000 blows will exhaust the usefulness of the cushion of +the stamp machine, and this number of blows is given in a day; and that +when a cushion of aluminum bronze was substituted, it was unaffected +after months of use. + +If we have found a metal that possesses both tensile strength and +resistance to compression; malleability and ductility--the quality of +hardening, softening, and toughening by tempering; adaptability to +casting, rolling, or forging; susceptibility to luster and finish; of +complete homogeneous character and unusually resistant to destructive +agents--mankind will certainly leave the present accomplishments as +belonging to an effete past, and, as it were, start anew in a career of +greater prospects. + +This important material is to be found largely in nearly all the rocks, +or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal." +It is in every clay bank. It is particularly abundant in the coal +measures and is incidental to the shales or slates and clays that +underlie the coal. This under clay of the coal stratum was in all +probability the soil out of which grew the vegetation of the coal +deposits. It is a compound of aluminum and other matter, and, when mixed +with carbon and transformed by the processes of geologic action, it +becomes the shale rock which we know and which we discard as worthless +slate. And it is barely possible that we have been and are still carting +to the refuse pile an article more valuable than the so greatly lauded +coal waste or the merchantable coal itself. We have seen that the best +alumina ore contains only fifty-four per cent. of metal. + +The following prepared table has been furnished by the courtesy and +kindness of Mr. Alex. H. Sherred, of Scranton. + + ALUMINA. + +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 + +It will be seen that the black clay, shale, or slate, has a constituent +of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the +highest. Under every stratum of coal, and frequently mixed with it, are +these under deposits that are rich in the metal. When exposed to the +atmosphere, these shales yield a small deposit of alum. In the +manufacture of alum near Glasgow the shale and slate clay from the old +coal pits constitute the material used, and in France alum is +manufactured directly from the clay. + +Sufficient has been advanced to warrant the additional assertion that we +are here everywhere surrounded by this incomparable mineral, that it is +brought to the surface from its deposits deep in the earth by the +natural process in mining, and is only exceeded in quantity by the coal +itself. Taking a columnar section of our coal field, and computing the +thickness of each shale stratum, we have from twenty-five to sixty feet +in thickness of this metal-bearing substance, which averages over +twenty-five per cent. of the whole in quantity in metal. + +It is readily apparent that the only task now before us is the reduction +of the ore and the extraction of the metal. Can this be done? We answer, +it has been done. The egg has stood on end--the new world has been +sighted. All that now remains is to repeat the operation and extend the +process. Cheap aluminum will revolutionize industry, travel, comfort, +and indulgence, transforming the present into an even greater +civilization. Let us see. + +We have seen the discovery of the mere chemical existence of the metal, +we have stood by the birth of the first white globule or bead by Wohler, +in 1846, and witnesssed its introduction as a manufactured product in +1855, since which time, by the alteration and cheapening of one process +after another, it has fallen in price from thirty-two dollars per pound +in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent +labor at smelting have increased the quantity over a thousandfold and +reduced the cost upward of fifty per cent. + +All these processes involve the application of heat--a mere question of +the appliances. The electric currents of Berzelius and Oersted, the +crucible of Wohler, the closed furnaces and the hydrogen gas of the +French manufacturers and the Bessemer converter apparatus of Thompson, +all indicate one direction. This metal can be made to abandon its bed in +the earth and the rock at the will of man. During the past year, the +Messrs. Cowles, of Cleveland, by their electric smelting process, claim +to have made it possible to reduce the price of the metal to below four +dollars per pound; and there is now erecting at Lockport, New York, a +plant involving one million of capital for the purpose. + +Turning from the employment of the expensive reducing agents to the +simple and sole application of heat, we are unwilling to believe that we +do not here possess in eminence both the mineral and the medium of its +reduction. Whether the electric or the reverberatory or the converter +furnace system be employed, it is surely possible to produce the result. + +To enter into consideration of the details of these constructions would +involve more time than is permitted us on this occasion. They are very +interesting. We come again naturally to the limitless consideration of +powdered fuel, concerning which certain conclusions have been reached. +In the dissociation of water into its hydrogen and oxygen, with the +mingled carbon in a powdered state, we undoubtedly possess the elements +of combustion that are unexcelled on earth, a heat-producing combination +that in both activity and power leaves little to be desired this side of +the production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and furnaces. + +In the hope of stimulating thought to this infinite question of proper +fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope this +Board will not grudgingly devote to the subject, but which is impossible +at present. Do not forget that there is no single spot on the face of +the globe where nature has lavished more freely her choicest gifts. Let +us be active in the pursuit of the treasure and grateful for the +distinguished consideration. + + * * * * * + + + + +THE ORIGIN OF METEORITES. + + +On January 9, Professor Dewar delivered the sixth and last of his series +of lectures at the Royal Institution on "The Story of a Meteorite." [For +the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that +cosmic dust is found on Arctic snows and upon the bottom of the ocean; +all over the world, in fact, at some time or other, there has been a +large deposit of this meteoric dust, containing little round nodules +found also in meteorites. In Greenland some time ago numbers of what +were supposed to be meteoric stones were found; they contained iron, and +this iron, on being analyzed at Copenhagen, was found to be rich in +nickel. The Esquimaux once made knives from iron containing nickel; and +as any such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited the +basaltic coast in Greenland from which some of the supposed meteoric +stones had been brought, and in the middle of the rock large nodules +were found composed of iron and nickel; it, therefore, became evident +that the earth might produce masses not unlike such as come to us as +meteorites. The lecturer here exhibited a section of the Greenland rock +containing the iron, and nickel alloy, mixed with stony crystals, and +its resemblance to a section of a meteorite was obvious. It was 2½ times +denser than water, yet the whole earth is 5½ times denser than water, so +that if we could go deep enough, it is not improbable that our own globe +might be found to contain something like meteoric iron. He then called +attention to the following tables: + + _Elementary Substances found in Meteorites_. + + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. + +_Density of Meteorites_. + + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 + +_Interior of the Earth_ + + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 + +[Illustration] + +Twice a year, said Professor Dewar, what are called "falling stars" +maybe plentifully seen; the times of their appearance are in August and +November. Although thousands upon thousands of such small meteors have +passed through our atmosphere, there is no distinct record of one having +ever fallen to the earth during these annual displays. One was said to +have fallen recently at Naples, but on investigation it turned out to be +a myth. These annual meteors in the upper air are supposed to be only +small ones, and to be dissipated into dust and vapor at the time of +their sudden heating; so numerous are they that 40,000 have been counted +in one evening, and an exceptionally great display comes about once in +33¼ years. The inference from their periodicity is, that they are small +bodies moving round the sun in orbits of their own, and that whenever +the earth crosses their orbits, thereby getting into their path, a +splendid display of meteors results. A second display, a year later, +usually follows the exceptionally great display just mentioned, +consequently the train of meteors is of great length. Some of these +meteors just enter the atmosphere of the earth, then pass out again +forever, with their direction of motion altered by the influence of the +attraction of the earth. He here called attention to the accompanying +diagram of the orbits of meteors. + +The lecturer next invited attention to a hollow globe of linen or some +light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and +contained hidden within it the great electro-magnet, weighing 2 cwt., so +often used by Faraday in his experiments. He also exhibited a ball made +partly of thin iron; the globe represented the earth, for the purposes +of the experiment, and the ball a meteorite of somewhat large relative +size. The ball was then discharged at the globe from a little catapult; +sometimes the globe attracted the ball to its surface, and held it +there, sometimes it missed it, but altered its curve of motion through +the air. So was it, said the lecturer, with meteorites when they neared +the earth. Photographs from drawings, by Professor A. Herschel, of the +paths of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, is a +proof that their motions are parallel to each other; the parallel lines +seem to draw to a point at the greatest distance, for the same reason +that the rails of a straight line of railway seem to come from a distant +central point. The most interesting thing about the path of a company of +meteors is, that a comet is known to move in the same orbit; the comet +heads the procession, the meteors follow, and they are therefore, in all +probability, parts of comets, although everything about these difficult +matters cannot as yet be entirely explained; enough, however, is known +to give foundation for the assumption that meteorites and comets are not +very dissimilar. + +The light of a meteorite is not seen until it enters the atmosphere of +the earth, but falling meteorites can be vaporized by electricity, and +the light emitted by their constituents be then examined with the +spectroscope. The light of comets can be directly examined, and it +reveals the presence in those bodies of sodium, carbon, and a few other +well-known substances. He would put a piece of meteorite in the electric +arc to see what light it would give; he had never tried the experiment +before. The lights of the theater were then turned down, and the +discourse was continued in darkness; among the most prominent lines +visible in the spectrum of the meteorite, Professor Dewar specified +magnesium, sodium, and lithium. "Where do meteorites come from?" said +the lecturer. It might be, he continued, that they were portions of +exploded planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular hypothesis +that at some long past time our sun and all his planets existed but as a +volume of gas, which in contracting and cooling formed a hot volume of +rotating liquid, and that as this further contracted and cooled, the +planets, and moons, and planetary rings fell off from it and gradually +solidified, the sun being left as the solitary comparatively uncooled +portion of the original nebula. In partial illustration of this, he +caused a little globe of oil, suspended in an aqueous liquid of nearly +its own specific gravity, to rotate, and as it rotated it was seen, by +means of its magnified image upon the screen, to throw off from its +outer circumference rings and little globes. + + * * * * * + + + + +CANDELABRA CACTUS AND CALIFORNIA WOODPECKER. + +By C.F. HOLDER. + + +One of the most picturesque objects that meet the eye of the traveler +over the great plains of the southern portion of California and New +Mexico is the candelabra cactus. Systematically it belongs to the Cereus +family, in which the notable Night-blooming Cereus also is naturally +included. In tropical or semi-tropical countries these plants thrive, +and grow to enormous size. For example, the Cereus that bears those +great flowers, and blooms at night, exhaling powerful perfume, as we see +them in hothouses in our cold climate, are even in the semi-tropical +region of Key West, on the Florida Reef, seen to grow enormously in +length. + +[Illustration: THE CANDELABRA CACTUS--CEREUS GIGANTEUS.] + +We cultivated several species of the more interesting forms during a +residence on the reef. Our brick house, two stories in height, was +entirely covered on a broad gable end, the branches more than gaining +the top. There is a regular monthly growth, and this is indicated by a +joint between each two lengths. Should the stalk be allowed to grow +without support, it will continue growing without division, and exhibit +stalks five or six feet in length, when they droop, and fall upon the +ground. + +Where there is a convenient resting place on which it can spread out and +attach itself, the stalk throws out feelers and rootlets, which fasten +securely to the wall or brickwork; then, this being a normal growth, +there is a separation at intervals of about a foot. That is, the stalk +grows in one month about twelve inches, and if it has support, the +middle woody stalk continues to grow about an inch further, but has no +green, succulent portion, in fact, looks like a stem; then the other +monthly growth takes place, and ends with a stem, and so on +indefinitely. Our house was entirely covered by the stems of such a +plant, and the flowers were gorgeous in the extreme. The perfume, +however, was so potent that it became a nuisance. Such is the +Night-blooming Cereus in the warm climates, and similarly the Candelabra +Cereus grows in stalks, but architecturally erect, fluted like columns. +The flowers are large, and resemble those of the night-blooming variety. +Some columns remain single, and are amazingly artificial appearing; +others throw off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being clusters +of side shoots, the latter putting out from the trunk regularly, and +standing up parallel to each other. The enormous size these attain is +well shown in the picture. + +Whenever the great stalks of these cacti die, the succulent portion is +dried, and nothing is left but the woody fiber. They are hollow in +places, and easily penetrated. A species of woodpecker, _Melanerpes +formicivorus_, is found to have adopted the use of these dry stalks for +storing the winter's stock of provisions. There are several round +apertures seen on the stems in the pictures, which were pecked by this +bird. This species of woodpecker is about the size of our common robin +or migratory thrush, and has a bill stout and sharp. The holes are +pecked for the purpose of storing away acorns or other nuts; they are +just large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts are +so numerous, the stalk has the appearance of being studded with bullets. +This appearance is more pronounced in cases where the dead trunk of an +oak is used. There are some specimens of the latter now owned by the +American Museum of Natural History, which were originally sent to the +Centennial Exhibition at Philadelphia. They were placed in the +department contributed by the Pacific Railroad Company, and at that time +were regarded as some of the wonders of that newly explored region +through which the railroad was then penetrating. Some portions of the +surface of these logs are nearly entirely occupied by the holes with +acorns in them. The acorns are driven in very tightly in these examples; +much more so than in the cactus plants, as the oak is nearly round, and +the holes were pecked in solid though dead wood. One of the most +remarkable circumstances connected with this habit of the woodpecker is +the length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to make a +journey of sixty miles to accomplish the storing of one acorn. At first +it seemed strange that a bird should spend so much labor to place those +bits of food, and so far away. De Saussure, a Swiss naturalist, +published in the _Bibliotheque Universelle_, of Geneva, entertaining +accounts of the Mexican Colaptes, a variety of the familiar "high hold," +or golden winged woodpecker. They were seen to store acorns in the dead +stalks of the maguey (_Agave Americana_). Sumichrast, who accompanied +him to Central America, records the same facts. These travelers saw +great numbers of the woodpeckers in a region on the slope of a range of +volcanic mountains. There was little else of vegetation than the +_Agave_, whose barren, dead stems were studded with acorns placed there +by the woodpeckers. + +The maguey throws up a stalk about fifteen feet in height yearly, which, +after flowering, grows stalky and brittle, and remains an unsightly +thing. The interior is pithy, but after the death of the stalk the pith +contracts, and leaves the greater portion of the interior hollow, as we +have seen in the case of the cactus branches. How the birds found that +these stalks were hollow is a problem not yet solved, but, nevertheless, +they take the trouble to peck away at the hard bark, and once +penetrated, they commence to fill the interior; when one space is full, +the bird pecks a little higher up, and so continues. + +Dr. Heerman, of California, describes the California _Melanerpes_ as one +of the most abundant of the woodpeckers; and remarks that it catches +insects on the wing like a flycatcher. It is well determined that it +also eats the acorns that it takes so much pains to transport. + +[Illustration: FLOWER OF CEREUS GIGANTEUS.] + +It seems that these birds also store the pine trees, as well as the +oaks. It is not quite apparent why these birds exhibit such variation in +habits; they at times select the more solid trees, where the storing +cannot go on without each nut is separately set in a hole of its own. +There seems an instinct prompting them to do this work, though there may +not be any of the nuts touched again by the birds. Curiously enough, +there are many instances of the birds placing pebbles instead of nuts in +holes they have purposely pecked for them. Serious trouble has been +experienced by these pebbles suddenly coming in contact with the saw of +the mill through which the tree is running. The stone having been placed +in a living tree, as is often the case, its exterior had been lost to +sight during growth. + +Some doubt has been entertained about the purpose of the bird in storing +the nuts in this manner. De Saussure tells us he has witnessed the birds +eating the acorns after they had been placed in holes in trees, and +expresses his conviction that the insignificant grub which is only seen +in a small proportion of nuts is not the food they are in search of. + +C.W. Plass, Esq., of Napa City, California, had an interesting example +of the habits of the California _Melanerpes_ displayed in his own house. +The birds had deposited numbers of acorns in the gable end. A +considerable number of shells were found dropped underneath the eaves, +while some were found in place under the gable, and these were perfect, +having no grubs in them. + +The picture shows a very common scene in New Mexico. The columns, +straight and angular, are often sixty feet in height. It is called torch +cactus in some places. There are many varieties, and as many different +shapes. Some lie on the ground; others, attached to trunks of trees as +parasites, hang from branches like great serpents; but none is so +majestic as the species called systematically _Cereus giganteus_, most +appropriately. The species growing pretty abundantly on the island of +Key West is called candle cactus. It reaches some ten or twelve feet, +and is about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a pretty, +rather picturesque feature in the otherwise barren undergrowth of +shrubbery and small trees. Accompanied by a few flowering cocoa palms, +the view is not unpleasing. The fiber of these plants is utilized in +some coarse manufactures. The maguey, or Agave, is used in the +manufacture of fine roping. Manila hemp is made from a species. The +species whose dried stalks are used by the woodpeckers for their winter +storage was cultivated at Key West, Florida, during several years before +1858. Extensive fields of the Agave stood unappropriated at that period. +Considerable funds were dissipated on this venture. Extensive works were +established, and much confidence was entertained that the scheme would +prove a paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their long +stalks, stand now, increasing every year, until a portion of the island +is overrun with them. + + +CEREUS GIGANTEUS. + +This wonderful cactus, its colossal proportions, and weird, yet grand, +appearance in the rocky regions of Mexico and California, where it is +found in abundance, have been made known to us only through books of +travel, no large plants of it having as yet appeared in cultivation in +this country. It is questionable if ever the natural desire to see such +a vegetable curiosity represented by a large specimen in gardens like +Kew can be realized, owing to the difficulty of importing large stems in +a living condition; and even if successfully brought here, they survive +only a very short time. To grow young plants to a large size seems +equally beyond our power, as plants 6 inches high and carefully managed +are quite ten years old. When young, the stem is globose, afterward +becoming club-shaped or cylindrical. It flowers at the height of 12 +feet, but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of an +immense candelabrum, the base of the stem being as thick as a man's +body. The flower, of which a figure is given here, is about 5 inches +long and wide, the petals cream colored, the sepals greenish white. +Large clusters of flowers are developed together near the top of the +stem. A richly colored edible fruit like a large fig succeeds each +flower, and this is gathered by the natives and used as food under the +name of saguarro. A specimen of this cactus 3 feet high may be seen in +the succulent house at Kew.--_B., The Garden_. + + * * * * * + + + + +HOW PLANTS ARE REPRODUCED. + +[Footnote: Read at a meeting of the Chemists' Assistants' Association. +December 16, 1885.] + +By C.E. STUART, B.Sc. + + +In two previous papers read before this Association I have tried to +condense into as small a space as I could the processes of the nutrition +and of the growth of plants; in the present paper I want to set before +you the broad lines of the methods by which plants are reproduced. + +Although in the great trees of the conifers and the dicotyledons we have +apparently provision for growth for any number of years, or even +centuries, yet accident or decay, or one of the many ills that plants +are heirs to, will sooner or later put an end to the life of every +individual plant. + +Hence the most important act of a plant--not for itself perhaps, but for +its race--is the act by which it, as we say, "reproduces itself," that +is, the act which results in the giving of life to a second individual +of the same form, structure, and nature as the original plant. + +The methods by which it is secured that the second generation of the +plant shall be as well or even better fitted for the struggle of life +than the parent generation are so numerous and complicated that I cannot +in this paper do more than allude to them; they are most completely seen +in cross fertilization, and the adaptation of plant structures to that +end. + +What I want to point out at present are the principles and not so much +the details of reproduction, and I wish you to notice, as I proceed, +what is true not only of reproduction in plants but also of all +processes in nature, namely, the paucity of typical methods of attaining +the given end, and the multiplicity of special variation from those +typical methods. When we see the wonderfully varied forms of plant life, +and yet learn that, so to speak, each edifice is built with the same +kind of brick, called a cell, modified in form and function; when we see +the smallest and simplest equally with the largest and most complicated +plant increasing in size subject to the laws of growth by +intussusception and cell division, which are universal in the organic +world; we should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types. + +The first great generalization is into-- + +1. The vegetative type of reproduction, in which one or more ordinary +cells separate from the parent plant and become an independent plant; +and-- + +2. The special-cell type of reproduction, in which either one special +cell reproduces the plant, or two special cells by their union form the +origin of the new plant; these two modifications of the process are +known respectively as asexual and sexual. + +The third modification is a combination of the two others, namely, the +asexual special cell does not directly reproduce its parent form, but +gives rise to a structure in which sexual special cells are developed, +from whose coalescence springs again the likeness of the original plant. +This is termed alternation of generations. + +The sexual special cell is termed the _spore_. + +The sexual special cells are of one kind or of two kinds. + +Those which are of one kind may be termed, from their habit of yoking +themselves together, _zygoblasts_, or conjugating cells. + +Those which are of two kinds are, first, a generally aggressive and +motile fertilizing or so-called "male cell," called in its typical form +an _antherozoid_; and, second, a passive and motionless receptive or +so-called "female cell," called an _oosphere_. + +The product of the union of two zygoblasts is termed a _zygospore_. + +The product of the union of an antherozoid and an oosphere is termed an +_oospore_. + +In many cases the differentiation of the sexual cells does not proceed +so far as the formation of antherozoids or of distinct oospheres; these +cases I shall investigate with the others in detail presently. + +First, then, I will point out some of the modes of vegetative +reproduction. + +The commonest of these is cell division, as seen in unicellular plants, +such as protococcus, where the one cell which composes the plant simply +divides into two, and each newly formed cell is then a complete plant. + +The particular kind of cell division termed "budding" here deserves +mention. It is well seen in the yeast-plant, where the cell bulges at +one side, and this bulge becomes larger until it is nipped off from the +parent by contraction at the point of junction, and is then an +independent plant. + +Next, there is the process by which one plant becomes two by the dying +off of some connecting portion between two growing parts. + +Take, for instance, the case of the liverworts. In these there is a +thallus which starts from a central point and continually divides in a +forked or dichotomous manner. Now, if the central portion dies away, it +is obvious that there will be as many plants as there were forkings, and +the further the dying of the old end proceeds, the more young plants +will there be. + +Take again, among higher plants, the cases of suckers, runners, stolons, +offsets, etc. Here, by a process of growth but little removed from the +normal, portions of stems develop adventitious roots, and by the dying +away of the connecting links may become independent plants. + +Still another vegetative method of reproduction is that by bulbils or +gemmæ. + +A bulbil is a bud which becomes an independent plant before it commences +to elongate; it is generally fleshy, somewhat after the manner of a +bulb, hence its name. Examples occur in the axillary buds of _Lilium +bulbiferum_, in some _Alliums_, etc. + +The gemma is found most frequently in the liverworts and mosses, and is +highly characteristic of these plants, in which indeed vegetative +reproduction maybe said to reach its fullest and most varied extent. + +Gemmæ are here formed in a sort of flat cup, by division of superficial +cells of the thallus or of the stem, and they consist when mature of +flattened masses of cells, which lie loose in the cup, so that wind or +wet will carry them away on to soil or rock, when, either by direct +growth from apical cells, as with those of the liverworts, or with +previous emission of thread-like cells forming a "protonema," in the +case of the mosses, the young plant is produced from them. + +The lichens have a very peculiar method of gemmation. The lichen-thallus +is composed of chains or groups of round chlorophyl-containing cells, +called "gonidia," and masses of interwoven rows of elongated cells which +constitute the hyphæ. Under certain conditions single cells of the +gonidia become surrounded with a dense felt of hyphæ, these accumulate +in numbers below the surface of the thallus, until at last they break +out, are blown or washed away, and start germination by ordinary cell +division, and thus at once reproduce a fresh lichen-thallus. These +masses of cells are called soredia. + +Artificial budding and grafting do not enter into the scope of this +paper. + +As in the general growth and the vegetative reproduction of plants +cell-division is the chief method of cell formation, so in the +reproduction of plants by special cells the great feature is the part +played by cells which are produced not by the ordinary method of cell +division, but by one or the other processes of cell formation, namely, +free-cell formation or rejuvenescence. + +If we broaden somewhat the definition of rejuvenescence and free-cell +formation, and do not call the mother-cells of spores of mosses, higher +cryptogams, and also the mother-cells of pollen-grains, reproductive +cells, which strictly speaking they are not, but only producers of the +spores or pollen-grains, then we may say that _cell-division is confined +to vegetative processes, rejuvenescence and free-cell formation are +confined to reproductive processes_. + +Rejuvenescence may be defined as the rearrangement of the whole of the +protoplasm of a cell into a new cell, which becomes free from the +mother-cell, and may or may not secrete a cell-wall around it. + +If instead of the whole protoplasm of the cell arranging itself into one +mass, it divides into several, or if portions only of the protoplasm +become marked out into new cells, in each case accompanied by rounding +off and contraction, the new cells remaining free from one another, and +usually each secreting a cell wall, then this process, whose relation to +rejuvenescence is apparent, is called free-cell formation. + +The only case of purely vegetative cell-formation which takes place by +either of these processes is that of the formation of endosperm in +Selaginella and phanerogams, which is a process of free-cell formation. + +On the other hand, the universal contraction and rounding off of the +protoplasm, and the formation by either rejuvenescence or free-cell +formation, distinctly mark out the special or true reproductive cell. + +Examples of reproductive cells formed by rejuvenescence are: + +1. The swarm spores of many algæ, as Stigeoclonium (figured in Sachs' +"Botany"). Here the contents of the cell contract, rearrange themselves, +and burst the side of the containing wall, becoming free as a +reproductive cell. + +2. The zygoblasts of conjugating algæ, as in Spirogyra. Here the +contents of a cell contract and rearrange themselves only after contact +of the cell with one of another filament of the plant. This zygoblast +only becomes free after the process of conjugation, as described below. + +3. The oosphere of characeæ, mosses and liverworts, and vascular +cryptogams, where in special structures produced by cell-divisions there +arise single primordial cells, which divide into two portions, of which +the upper portion dissolves or becomes mucilaginous, while the lower +contracts and rearranges itself to form the oosphere. + +4. Spores of mosses and liverworts, of vascular cryptogams, and pollen +cells of phanerogams, which are the analogue of the spores. + +The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes a +wall of its own, and by the bursting or absorption of the wall of its +mother-cell becomes free. This is evidently a rejuvenescence. + +Examples of reproductive cells formed by free-cell formation are: + +1. The ascospores of fungi and algæ. + +2. The zoospores or mobile spores of many algæ and fungi. + +3. The germinal vesicles of phanerogams. + +The next portion of my subject is the study of the methods by which +these special cells reproduce the plant. + +1st. Asexual methods. + +1. Rejuvenescence gives rise to a swarm-spore or zoospore. The whole of +the protoplasm of a cell contracts, becomes rounded and rearranged, and +escapes into the water, in which the plant floats as a mass of +protoplasm, clear at one end and provided with cilia by which it is +enabled to move, until after a time it comes to rest, and after +secreting a wall forms a new plant by ordinary cell-division. Example: +Oedogonium. + +2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya. + +3. Free-cell formation forms the typical motionless spore of algæ and +fungi. For instance, in the asci of lichens there are formed from a +portion of the protoplasm four or more small ascospores, which secrete a +cell-wall and lie loose in the ascus. Occasionally these spores may +consist of two or more cells. They are set free by the rupture of the +ascus, and germinate by putting out through their walls one or more +filaments which branch and form the thallus of a new individual. Various +other spores formed in the same way are known as _tetraspores_, etc. + +4. Cell-division with rejuvenescence forms the spores of mosses and +higher cryptogams. + +To take the example of moss spores: + +Certain cells in the sporogonium of a moss are called mother-cells. The +protoplasm of each one of these becomes divided into four parts. Each of +these parts then secretes a cell-wall and becomes free as a spore by the +rupture or absorption of the wall of the mother-cell. The germination of +the spores I shall describe later. + +5. A process of budding which in the yeast plant and in mosses is merely +vegetatively reproductive, in fungi becomes truly reproductive, namely, +the buds are special cells arising from other special cells of the +hyphæ. + +For example, the so-called "gills" of the common mushroom have their +surface composed of the ends of the threads of cells constituting the +hyphæ. Some of these terminal cells push out a little finger of +protoplasm, which swells, thickens its wall, and becomes detached from +the mother-cell as a spore, here called specially a _basidiospore_. + +Also in the common gray mould of infusions and preserves, Penicillium, +by a process which is perhaps intermediate between budding and +cell-division, a cell at the end of a hypha constricts itself in several +places, and the constricted portions become separate as _conidiospores_. + +_Teleutospores, uredospores_, etc., are other names for spores similarly +formed. + +These conidiospores sometimes at once develop hyphæ, and sometimes, as +in the case of the potato fungus, they turn out their contents as a +swarm-spore, which actively moves about and penetrates the potato leaves +through the stomata before they come to rest and elongate into the +hyphal form. + +So far for asexual methods of reproduction. + +I shall now consider the sexual methods. + +The distinctive character of these methods is that the cell from which +the new individual is derived is incapable of producing by division or +otherwise that new individual without the aid of the protoplasm of +another cell. + +Why this should be we do not know; all that we can do is to guess that +there is some physical or chemical want which is only supplied through +the union of the two protoplasmic masses. The process is of benefit to +the species to which the individuals belong, since it gives it a greater +vigor and adaptability to varying conditions, for the separate +peculiarities of two individuals due to climatic or other conditions are +in the new generation combined in one individual. + +The simplest of the sexual processes is conjugation. Here the two +combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union. + +Conjugation occurs in algæ and fungi. A typical case is that of +Spirogyra. This is an alga with its cells in long filaments. Two +contiguous cells of two parallel filaments push each a little projection +from its cell-wall toward the other. When these meet, the protoplasm of +each of the two cells contracts, and assumes an elliptical form--it +undergoes rejuvenescence. Next an opening forms where the two cells are +in contact, and the contents of one cell pass over into the other, where +the two protoplasmic bodies coalesce, contract, and develop a cell-wall. +The zygospore thus formed germinates after a long period and forms a new +filament of cells. + +Another example of conjugation is that of Pandorina, an alga allied to +the well-known volvox. Here the conjugating cells swim free in water; +they have no cell-wall, and move actively by cilia. Two out of a number +approach, coalesce, contract, and secrete a cell-wall. After a long +period of rest, this zygospore allows the whole of its contents to +escape as a swarm-spore, which after a time secretes a gelatinous wall, +and by division reproduces the sixteen-celled family. + +We now come to fertilization, where the uniting cells are of two kinds. + +The simplest case is that of Vaucheria, an alga. Here the vegetative +filament puts out two protuberances, which become shut off from the body +of the filament by partitions. The protoplasm in one of these +protuberances arranges itself into a round mass--the oosphere or female +cell. The protoplasm of the other protuberance divides into many small +masses, furnished with cilia, the spermatozoids or male cells. Each +protuberance bursts, and some of the spermatozoids come in contact with +and are absorbed by the oosphere, which then secretes a cell-wall, and +after a time germinates. + +The most advanced type of fertilization is that of angiosperms. + +In them there are these differences from the above process: the contents +of the male cell, represented by the pollen, are not differentiated into +spermatozoids, and there is no actual contact between the contents of +the pollen tube and the germinal vesicle, but according to Strashurger, +there is a transference of the substance of the nucleus of the pollen +cell to that of the germinal vesicle by osmose. The coalescence of the +two nuclei within the substance of the germinal vesicle causes the +latter to secrete a wall, and to form a new plant by division, being +nourished the while by the mother plant, from whose tissues the young +embryo plant contained in the seed only becomes free when it is in an +advanced stage of differentiation. + +Perhaps the most remarkable cases of fertilization occur in the Florideæ +or red seaweeds, to which class the well-known Irish moss belongs. + +Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, some +other cell which is quite distinct from the primarily fertilized cell +carries on the reproductive process. + +If the allied group of the Coleochæteæ is considered together with the +Florideæ, we find a transition between the ordinary case of Coleochæte +and that of Dudresnaya. In Coleochæte, the male cell is a round +spermatozoid, and the female cell an oosphere contained in the base of a +cell which is elongated into an open and hair-like tube called the +trichogyne. The spermatozoid coalesces with the oosphere, which secretes +a wall, becomes surrounded with a covering of cells called a cystocarp, +which springs from cells below the trichogyne, and after the whole +structure falls from the parent plant, spores are developed from the +oospore, and from them arises a new generation. + +In Dudresnaya, on the other hand, the spermatozoid coalesces indeed with +the trichogyne, but this does not develop further. From below the +trichogyne, however, spring several branches, which run to the ends of +adjacent branches, with the apical cells of which they conjugate, and +the result of this conjugation is the development of a cystocarp similar +to that of Coleochæte. The remarkable point here is the way in which the +effect of the fertilizing process is carried from one cell to another +entirely distinct from it. + +Thus I have endeavored to sum up the processes of asexual and of sexual +reproduction. But it is a peculiar characteristic of most classes of +plants that the cycle of their existence is not complete until both +methods of reproduction have been called into play, and that the +structure produced by one method is entirely different from that +produced by the other method. + +Indeed, it is only in some algæ and fungi that the reproductive cells of +one generation produce a generation similar to the parent; in all other +plants a generation A produces are unlike generation B, which may either +go on to produce another generation, C, and then back to A, or it may go +on producing B's until one of these reproduces A, or again it may +directly reproduce; A. Thus we have the three types: + + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. + +The first case is not common, the usual number of generations being two +only; but a typical example of the occurrence of three generations is in +such fungi as _Puccinia Graminis_. Here the first generation grows on +barberry leaves, and produces a kind of spore called an _æcidium spore_. +These æcidium spores germinate only on a grass stem or leaf, and a +distinct generation is produced, having a particular kind of spore +called an _uredospore_. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation with +another kind of spore, called a _teleutospore_, is produced. + +The teleutospores only germinate on barberry leaves, and there reproduce +the original æcidium generation. + +Thus we have the series A.B.B.B ... BCA + +In this instance all the generations are asexual, but the most common +case is for the sexual and the asexual generations to alternate. I will +describe as examples the reproduction of a moss, a fern, and a +dicotyledon. + +In such a typical moss as Funaria, we have the following cycle of +developments: The sexual generation is a dioecious leafy structure, +having a central elongated axis, with leaves arranged regularly around +and along it. At the top of the axis in the male plant rise the +antheridia, surrounded by an envelope of modified leaves called the +perigonium. The antheridia are stalked sacs, with a single wall of +cells, and the spiral antherozoids arise by free-cell formation from the +cells of the interior. They are discharged by the bursting of the +antheridium, together with a mucilage formed of the degraded walls of +their mother cells. + +In the female plant there arise at the apex of the stem, surrounded by +an envelope of ordinary leaves, several archegonia. These are of the +ordinary type of those organs, namely, a broad lower portion, containing +a naked oosphere and a long narrow neck with a central canal leading to +the oosphere. Down this canal pass one or more antherozoids, which +become absorbed into the oosphere, and this then secretes a wall, and +from it grows the second or asexual generation. The peculiarity of this +asexual or spore-bearing plant is that it is parasitic on the sexual +plant; the two generations, although not organically connected, yet +remain in close contact, and the spore-bearing generation is at all +events for a time nourished by the leafy sexual generation. + +The spore-bearing generation consists of a long stalk, closely held +below by the cells of the base of the archegonium; this supports a +broadened portion which contains the spores, and the top is covered with +the remains of the neck of the archegonium forming the calyptra. + +The spores arise from special or mother-cells by a process of division, +or it may be even termed free-cell formation, the protoplasm of each +mother-cell dividing into four parts, each of which contracts, secretes +a wall, and thus by rejuvenescence becomes a spore, and by the +absorption of the mother-cells the spores lie loose in the spore sac. +The spores are set free by the bursting of their chamber, and each +germinates, putting out a branched thread of cells called a protonema, +which may perhaps properly be termed a third generation in the cycle of +the plant; for it is only from buds developed on this protonema that the +leafy sexual plant arises. + +The characteristics, then, of the mosses are, that the sexual generation +is leafy, the one or two asexual generations are thalloid, and that the +spore-bearing generation is in parasitic connection with the sexual +generation. + +In the case of the fern, these conditions are very different. + +The sexual generation is a small green thalloid structure called a +prothallium, which bears antheridia and archegonia, each archegonium +having a neck-canal and oosphere, which is fertilized just as in the +moss. + +But the asexual generation derived from the oospore only for a short +while remains in connection with the prothallium, which, of course, +answers to the leafy portion of the moss. What is generally known as the +fern is this asexual generation, a great contrast to the small leafless +moss fruit or sporogonium as it is called, to which it is +morphologically equivalent. On the leaves of this generation arise the +sporangia which contain the spores. The spores are formed in a manner +very similar to those of the mosses, and are set free by rupture of the +sporangium. + +The spore produces the small green prothallium by cell-division in the +usual way, and this completes the cycle of fern life. + +The alternation of generations, which is perhaps most clear and typical +in the case of the fern, becomes less distinctly marked in the plants of +higher organization and type. + +Thus in the Rhizocarpæ there are two kinds of spores, _microspores_ and +_macrospores_, producing prothallia which bear respectively antheridia +and archegonia; in the Lycopodiaceæ, the two kinds of spores produce +very rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the endosperm, in +which archegonia or corpuscula are formed; and lastly, in typical +dicotyledons it is only lately that any trace of a prothallium from the +microspore or pollen cell has been discovered, while the macrospore or +embryo-sac produces only two or three prothallium cells, known as +antipodal cells, and two or three oospheres, known as germinal vesicles. + +This description of the analogies of the pollen and embryo-sac of +dicotyledons assumes that the general vegetative structure of this class +of plants is equivalent to the asexual generation of the higher +cryptogams. In describing their cycle of reproduction I will endeavor to +show grounds for this assumption. + +We start with the embryo as contained in the seed. This embryo is the +product of fertilization of a germinal vesicle by a pollen tube. Hence, +by analogy with the product of fertilization of rhizocarp's, ferns, and +mosses, it should develop into a spore bearing plant. It does develop +into a plant in which on certain modified leaves are produced masses of +tissue in which two kinds of special reproductive cells are formed. This +is precisely analogous to the case of gymnosperms, lycopods, etc., where +on leaf structures are formed macro and micro sporangia. + +To deal first with the microsporangium or pollen-sac. The pollen cells +are formed from mother cells by a process of cell division and +subsequent setting free of the daughter cells or pollen cells by +rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceæ, etc. The subsequent +behavior of the pollen cell, its division and its fertilization of the +germinal vesicle or oosphere, leave no doubt as to its analogy with the +microspore of vascular cryptogams. + +Secondly, the nucleus of the ovule corresponds with the macrosporangium +of Selaginella, through the connecting link of the conifers, where the +ovule is of similar origin and position to the macrosporangium of the +Lycopodiaceæ. But the formation of the macrospore or embryo-sac is +simpler than the corresponding process in cryptogams. It arises by a +simple enlargement of one cell of the nucleus instead of by the division +of one cell into four, each thus becoming a macrospore. At the top of +this macrospore or embryo-sac two or three germinal vesicles are formed +by free cell formation, and also two or three cells called antipodal +cells, since they travel to the other end of the embryo-sac; these +latter represent a rudimentary prothallium. This formation of germinal +vesicles and prothallium seems very different from the formation of +archegonia and prothallium in Selaginella, for instance; but the link +which connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed. + +Thus we see that the flowering plant is essentially the equivalent of +the asexual fern, and of the sporogonium of the moss, and the pollen +cell and the embryo-sac represent the two spores of the higher +cryptogams, and the pollen tube and the germinal vesicles and antipodal +cells are all that remain of the sexual generation, seen in the moss as +a leafy plant, and in the fern as a prothallium. Indeed, when a plant +has monoecious or dioecious flowers, the distinction between the asexual +and the sexual generation has practically been lost, and the +spore-bearing generation has become identified with the sexual +generation. + +Having now described the formation of the pollen and the germinal +vesicles, it only remains to show how they form the embryo. The pollen +cell forms two or three divisions, which are either permanent or soon +absorbed; this, as before stated, is the rudimentary male prothallium. +Then when it lies on the stigma it develops a long tube, which passes +down the style and through the micropyle of the ovule to the germinal +vesicles, one of which is fertilized by what is probably an osmotic +transference of nuclear matter. The germinal vesicle now secretes a +wall, divides into two parts, and while the rest of the embyro-sac fills +with endosperm cells, it produces by cell division from the upper half a +short row of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or leafy +plant, and while in the fern each generation is an independent +structure, here in the dicotyledon, on the other hand, the asexual +generation or embryo is again for a time nourished in the interior of +the embryo-sac representing the sexual generation, and this again +derives its nourishment from the previous asexual generation, so that as +in the moss, there is again a partial parasitism of one generation on +the other. + +To sum up the methods of plant reproduction: They resolve themselves +into two classes. + +1st. Purely vegetative. + +2d. Truly reproductive by special cells. + +In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive methods. + +1st. Reproduction from an asexual spore. + +2d. Reproduction from an oospore formed by the combination of two sexual +cells. + +In the vast majority of plant species these two types are used by the +individuals alternately. + +The extraordinary similarity of the reproductive process, as shown in +the examples I have given, Achlya, Spirogyra, and Vaucheria among algæ, +the moss, the fern, and the flowering plant, a similarity which becomes +the more marked the more the details of each case and of the cases of +plants which form links between these great classes are studied, points +to a community of origin of all plants in some few or one primeval +ancestor. And to this inference the study of plant structure and +morphology, together with the evidence of palæobotany among other +circumstances, lends confirmatory evidence, and all modern discoveries, +as for instance that of the rudimentary prothallium formed by the pollen +of angiosperms, tend to the smoothing of the path by which the descent +of the higher plants from simpler types will, as I think, be eventually +shown. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +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. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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Address + +MUNN & CO., 361 BROADWAY, NEW YORK. + +Branch Office, 622 and 624 F St., Washington, D.C. + + + + + +End of the Project Gutenberg EBook of Scientific American Supplement, Vol. +XXI., No. 531, March 6, 1886, by Various + +*** END OF THE PROJECT GUTENBERG EBOOK 11383 *** diff --git a/11383-8.txt b/11383-8.txt new file mode 100644 index 0000000..6e2e931 --- /dev/null +++ b/11383-8.txt @@ -0,0 +1,4672 @@ +The Project Gutenberg EBook of Scientific American Supplement, Vol. XXI., +No. 531, March 6, 1886, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, Vol. XXI., No. 531, March 6, 1886 + +Author: Various + +Release Date: February 29, 2004 [EBook #11383] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPP. 531 *** + + + + +Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland, +Charles Franks and the DP Team + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 531 + + + + +NEW YORK, MARCH 6, 1886 + +Scientific American Supplement. Vol. XXI, No. 531. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY AND METALLURGY.--Annatto.-Analyses of the same.--By + WM. LAWSON + + Aluminum.--By J.A. PRICE.--Iron the basis of civilization.-- + Aluminum the metal of the future.--Discovery of aluminum.--Art + of obtaining the metal.--Uses and possibilities + +II. ENGINEERING AND MECHANICS.--The Use of Iron in Fortification. + --Armor-plated casements.--The Schumann-Gruson chilled iron + cupola.--Mougin's rolled iron cupola.--With full page + of engravings + + High Speed on the Ocean + + Sibley College Lectures.--Principles and Methods of Balancing + Forces developed in Moving Bodies.--Momentum and centrifugal + force.--By CHAS.T. PORTER.--3 figures + + Compressed Air Power Schemes.--By J. STURGEON.--Several + figures + + The Berthon Collapsible Canoe.--2 engravings + + The Fiftieth Anniversary of the Opening of the First German + Steam Railroad.--With full page engraving + + Improved Coal Elevator.--With engraving + +III. TECHNOLOGY.--Steel-making Ladles.--4 figures + + Water Gas.--The relative value of water gas and other gases as + Iron-reducing Agents.--By B.H. THWAITE.--Experiments.--With + tables and 1 figure + + Japanese Rice Wine and Soja Sauce.--Method of making + +IV. ELECTRICITY, MICROSCOPY, ETC.-Apparatus for demonstrating + that Electricity develops only on the Surface of Conductors.--1 + figure + + The Colson Telephone.--3 engravings + + The Meldometer.--An apparatus for determining the melting + points of minerals + + Touch Transmission by Electricity in the Education of Deaf + Mutes.--By S. TEFFT WALKER.--With 1 figure + +V. HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By + C.F. HOLDER.--With 2 engravings + + How Plants are reproduced.--By C.E. STUART.--A paper read + before the Chemists' Assistants' Association + +VI. MISCELLANEOUS--The Origin of Meteorites.--With 1 figure + + * * * * * + + + + +THE USE OF IRON IN FORTIFICATION. + + +Roumania is thinking of protecting a portion of the artillery of the +forts surrounding her capital by metallic cupolas. But, before deciding +upon the mode of constructing these formidable and costly affairs, and +before ordering them, she has desired to ascertain their efficacy and +the respective merits of the chilled iron armor which was recently in +fashion and of rolled iron, which looks as if it were to be the fashion +hereafter. + +[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.] + +The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a turret +of rolled iron. Both of these recommend themselves by various merits, +and by remarkably ingenious arrangements, and it only remains to be seen +how they will behave under the fire of the largest pieces of artillery. + +[Illustration: FIG. 2.] + +We are far in advance of the time when cannons with smooth bore were +obliged to approach to within a very short range of a scarp in order to +open a breach, and we are far beyond that first rifled artillery which +effected so great a revolution in tactics. + +[Illustration: FIG. 3.] + +To-day we station the batteries that are to tear open a rampart at +distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch +cannon that arms them has for probable deviations, under a charge of 20 +pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16 +inches in direct fire and 8 inches in curved. + +The weight of the projectile is 88 pounds, and its remanent velocity at +the moment of impact is 1,295 feet. Under this enormous live force, the +masonry gradually crumbles, and carries along the earth of the parapet, +and opens a breach for the assaulting columns. + +[Illustration: FIG. 4--STATE OF A CUPOLA AFTER THE ACTION OF +THIRTY-SEVEN 6 IN. PROJECTILES.] + +In order to protect the masonry of the scarp, engineers first lowered +the cordon to the level of the covert-way. Under these circumstances, +the enemy, although he could no longer see it, reached it by a curved or +"plunging" shot. When, in fact, for a given distance we load a gun with +the heaviest charge that it will stand, the trajectory, AMB (Fig. 2), is +as depressed as possible, and the angles, a and a', at the start and +arrival are small, and we have a direct shot. If we raise the chase of +the piece, the projectile will describe a curve in space which would be +a perfect parabola were it not for the resistance of the air, and the +summit of such curve will rise in proportion as the angle so increases. +So long as the falling angle, a, remains less than 45°, we shall have a +curved shot. When the angle exceeds this, the shot is called "vertical." +If we preserve the same charge, the parabolic curve in rising will meet +the horizontal plane at a greater distance off. This is, as well known, +the process employed for reaching more and more distant objects. + +[Illustration: Fig. 5.--STATE OF A CAST-IRON CUPOLA AFTER THE BREAKAGE +OF A VOUSSOIR.] + +The length of a gun depends upon the maximum charge burned in it, since +the combustion must be complete when the projectile reaches the open +air. It results from this that although guns of great length are capable +of throwing projectiles with small charges, it is possible to use +shorter pieces for this purpose--such as howitzers for curved shots and +mortars for vertical ones. The curved shot finds one application in the +opening of breaches in scarp walls, despite the existence of a covering +of great thickness. If, from a point, a (Fig. 3), we wish to strike the +point, b, of a scarp, over the crest, c, of the covert-way, it will +suffice to pass a parabolic curve through these three points--the +unknown data of the problem, and the charge necessary, being +ascertained, for any given piece, from the artillery tables. In such +cases it is necessary to ascertain the velocity at the impact, since the +force of penetration depends upon the live force (mv²) of the +projectile, and the latter will not penetrate masonry unless it have +sufficient remanent velocity. Live force, however, is not the sole +factor that intervenes, for it is indispensable to consider the angle at +which the projectile strikes the wall. Modern guns, such as the Krupp 6 +inch and De Bange 6 and 8 inch, make a breach, the two former at a +falling angle of 22°, and the latter at one of 30°. It is not easy to +lower the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass of the +glacis. + +The same guns are employed for dismounting the defender's pieces, which +he covers as much as possible behind the parapet. Heavy howitzers +destroy the _materiel_, while shrapnel, falling nearly vertically, and +bursting among the men, render all operations impossible upon an open +terre-plein. + +[Illustration: FIG. 6.--STATE OF A CHILLED IRON CUPOLA BROKEN BY A 12 +INCH BALL.] + +The effect of 6 and 8 inch rifled mortars is remarkable. The Germans +have a 9 inch one that weighs 3,850 pounds, and the projectile of which +weighs 300. But French mortars in nowise cede to those of their +neighbors; Col. De Bange, for example, has constructed a 10½ inch one of +wonderful power and accuracy. + +Seeing the destructive power of these modern engines of war, it may well +be asked how many pieces the defense will be able to preserve intact for +the last period of a siege--for the very moment at which it has most +need of a few guns to hold the assailants in check and destroy the +assaulting columns. Engineers have proposed two methods of protecting +these few indispensable pieces. The first of these consists in placing +each gun under a masonry vault, which is covered with earth on all sides +except the one that contains the embrasure, this side being covered with +armor plate. + +The second consists in placing one or two guns under a metallic cupola, +the embrasures in which are as small as possible. The cannon, in a +vertical aim, revolves around the center of an aperture which may be of +very small dimensions. As regards direct aim, the carriages are +absolutely fixed to the cupola, which itself revolves around a vertical +axis. These cupolas may be struck in three different ways: (1) at right +angles, by a direct shot, and consequently with a full charge--very +dangerous blows, that necessitate a great thickness of the armor plate; +(2) obliquely, when the projectile, if the normal component of its real +velocity is not sufficient to make it penetrate, will be deflected +without doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy. + +General Brialmont says that the metal of the cupola should be able to +withstand both penetration and breakage; but these two conditions +unfortunately require opposite qualities. A metal of sufficient +ductility to withstand breakage is easily penetrated, and, conversely, +one that is hard and does not permit of penetration does not resist +shocks well. Up to the present, casehardened iron (Gruson) has appeared +to best satisfy the contradictory conditions of the problem. Upon the +tempered exterior of this, projectiles of chilled iron and cast steel +break upon striking, absorbing a part of their live force for their own +breakage. + +In 1875 Commandant Mougin performed some experiments with a chilled iron +turret established after these plans. The thickness of the metal +normally to the blows was 23½ inches, and the projectiles were of cast +steel. The trial consisted in firing two solid 12 in. navy projectiles, +46 cylindrical 6 in. ones, weighing 100 lb., and 129 solid, pointed +ones, 12 in. in diameter. The 6 inch projectiles were fired from a +distance of 3,280 feet, with a remanent velocity of 1,300 feet. The +different phases of the experiment are shown in Figs. 4, 5, and 6. The +cupola was broken; but it is to be remarked that a movable and +well-covered one would not have been placed under so disadvantageous +circumstances as the one under consideration, upon which it was easy to +superpose the blows. An endeavor was next made to substitute a tougher +metal for casehardened iron, and steel was naturally thought of. But +hammered steel broke likewise, and a mixed or compound metal was still +less successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was rolled +iron. Armor plate composed of this latter has been submitted to several +tests, which appear to show that a thickness of 18 inches will serve as +a sufficient barrier to the shots of any gun that an enemy can +conveniently bring into the field. + +[Illustration: FIG. 7.--CASEMATE OF CHILLED IRON AFTER RECEIVING +NINETY-SIX SHOTS.] + +_Armor Plated Casemates_.--Fig. 7 shows the state of a chilled iron +casemate after a vigorous firing. The system that we are about to +describe is much better, and is due to Commandant Mougin. + +[Illustration: FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.] + +The gun is placed under a vault whose generatrices are at right angles +to the line of fire (Fig. 8), and which contains a niche that traverses +the parapet. This niche is of concrete, and its walls in the vicinity of +the embrasure are protected by thick iron plate. The rectangular armor +plate of rolled iron rests against an elastic cushion of sand compactly +rammed into an iron plate caisson. The conical embrasure traverses this +cushion by means of a cast-steel piece firmly bolted to the caisson, and +applied to the armor through the intermedium of a leaden ring. +Externally, the cheeks of the embrasure and the merlons consist of +blocks of concrete held in caissons of strong iron plate. The +surrounding earthwork is of sand. For closing the embrasure, Commandant +Mougin provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected by +the sloping mass of concrete that covers the head of the casemate. A +windlass and chain give the disk the motion that brings one of its +apertures opposite the embrasure or that closes the latter. When this +portion of the disk has suffered too much from the enemy's fire, a +simple maneuver gives it a half revolution, and the second aperture is +then made use of. + +_The Schumann-Gruson Chilled Iron Cupola_.--This cupola (Fig. 9) is +dome-shaped, and thus offers but little surface to direct fire; but it +can be struck by a vertical shot, and it may be inquired whether its top +can withstand the shock of projectiles from a 10 inch rifled mortar. It +is designed for two 6 inch guns placed parallel. Its internal diameter +is 19½ feet, and the dome is 8 inches in thickness and has a radius of +16½ feet. It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of relatively +small bulk--a bad feature as regards resistance to shock. To obviate +this difficulty, the inventor partitions it internally in such a way as +to leave only sufficient space to maneuver the guns. The partitions +consist of iron plate boxes filled with concrete. The form of the dome +has one inconvenience, viz., the embrasure in it is necessarily very +oblique, and offers quite an elongated ellipse to blows, and the edges +of the bevel upon a portion of the circumference are not strong enough. +In order to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides of +the embrasure. The motion of the piece necessary to aim it vertically is +effected around this axis of rotation. The weight of the gun is balanced +by a system of counterpoises and the chains, l, and the breech +terminates in a hollow screw, f, and a nut, g, held between two +directing sectors, h. The cupola is revolved by simply acting upon the +rollers. + +[Illustration: FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.] + +_Mougin's Rolled Iron Cupola_.--The general form of this cupola (Fig. 1) +is that of a cylindrical turret. It is 12¾ feet in diameter, and rises +3¼ feet above the top of the glacis. It has an advantage over the one +just described in possessing more internal space, without having so +large a diameter; and, as the embrasures are at right angles with the +sides, the plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of strong +iron plate strengthened by angle irons. Vertical partitions under the +cheeks of the gun carriages serve as cross braces, and are connected +with each other upon the table of the hydraulic pivot around which the +entire affair revolves. This pivot terminates in a plunger that enters a +strong steel press-cylinder embedded in the masonry of the lower +concrete vault. + +The iron plate ring carries wheels and rollers, through the intermedium +of which the turret is revolved. The circular iron track over which +these move is independent of the outer armor. + +The whole is maneuvered through the action of one man upon the piston of +a very small hydraulic press. The guns are mounted upon hydraulic +carriages. The brake that limits the recoil consists of two bronze pump +chambers, a and b (Fig. 10). The former of these is 4 inches in +diameter, and its piston is connected with the gun, while the other is 8 +inches in diameter, and its piston is connected with two rows of 26 +couples of Belleville springs, d. The two cylinders communicate through +a check valve. + +When the gun is in battery, the liquid fills the chamber of the 4 inch +pump, while the piston of the 8 inch one is at the end of its stroke. A +recoil has the effect of driving in the 4 inch piston and forcing the +liquid into the other chamber, whose piston compresses the springs. At +the end of the recoil, the gunner has only to act upon the valve by +means of a hand-wheel in order to bring the gun into battery as slowly +as he desires, through the action of the springs. + +[Illustration: FIG. 10.--MOUGIN'S HYDRAULIC GUN CARRIAGE.] + +For high aiming, the gun and the movable part of its carriage are +capable of revolving around a strong pin, c, so placed that the axis of +the piece always passes very near the center of the embrasure, thus +permitting of giving the latter minimum dimensions. The chamber of the 8 +inch pump is provided with projections that slide between circular +guides, and carries the strap of a small hydraulic piston, p, that +suffices to move the entire affair in a vertical plane, the gun and +movable carriage being balanced by a counterpoise, q. + +The projectiles are hoisted to the breech of the gun by a crane. + +Between the outer armor and turret sufficient space is left for a man to +enter, in order to make repairs when necessary. + +Each of the rolled iron plates of which the turret consists weighs 19 +tons. The cupolas that we have examined in this article have been +constructed on the hypothesis than an enemy will not be able to bring +into the field guns of much greater caliber than 6 inches.--_Le Genie +Civil_. + + * * * * * + + + + +HIGH SPEED ON THE OCEAN. + + +_To the Editor of the Scientific American_: + +Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN of +Jan. 2, 1886, in regard to high speed on the ocean. + +Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the plane +of their motion, but at an angle to it, the same principle would, if +applied to a steamship, increase its speed. But let us look at the +subject from another standpoint. The quadruped has to support the weight +of his body, and propel himself forward, with the same force. If the +force be applied perpendicularly, the body is elevated, but not moved +forward. If the force is applied horizontally, the body moves forward, +but soon falls to the ground, because it is not supported. But when the +force is applied at the proper angle, the body is moved forward and at +the same time supported. Directly contrary to Capt. Giles' theory, the +greater the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and _vice versa_. This may +easily be seen by any one watching the motions of the horse, hound, +deer, rabbit, etc., when in rapid motion. The water birds and animals, +whose weight is supported by the water, do not exert the propulsive +force in a downward direction, but in a direct line with the plane of +their motion. The man who swims does not increase his motion by kicking +out at an angle, but by drawing the feet together with the legs +straight, thus using the water between them as a double inclined plane, +on which his feet and legs slide and thus increase his motion. The +weight of the steamship is already supported by the water, and all that +is required of the propeller is to push her forward. If set so as to act +in a direct line with the plane of motion, it will use all its force to +push her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. If +placed at an angle of 45° with the plane of motion, half the force will +be used in raising the ship out of the water, and only half will be left +to push her forward. + +ENOS M. RICKER. + +Park Rapids, Minn., Jan. 23, 1886. + + * * * * * + + + + +SIBLEY COLLEGE LECTURES. + +BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING. + + + + +PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING BODIES. + +BY CHAS. T. PORTER. + +INTRODUCTION. + + +On appearing for the first time before this Association, which, as I am +informed, comprises the faculty and the entire body of students of the +Sibley College of Mechanical Engineering and the Mechanic Arts, a +reminiscence of the founder of this College suggests itself to me, in +the relation of which I beg first to be indulged. + +In the years 1847-8-9 I lived in Rochester, N.Y., and formed a slight +acquaintance with Mr. Sibley, whose home was then, as it has ever since +been, in that city. Nearly twelve years afterward, in the summer of +1861, which will be remembered as the first year of our civil war, I met +Mr. Sibley again. We happened to occupy a seat together in a car from +New York to Albany. He recollected me, and we had a conversation which +made a lasting impression on my memory. I said we had a conversation. +That reminds me of a story told by my dear friend, of precious memory, +Alexander L. Holley. One summer Mr. Holley accompanied a party of +artists on an excursion to Mt. Katahdin, which, as you know, rises in +almost solitary grandeur amid the forests and lakes of Maine. He wrote, +in his inimitably happy style, an account of this excursion, which +appeared some time after in _Scribner's Monthly_, elegantly illustrated +with views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. Katahdin. +"That is," he explained, "Mr. Church painted, and I held the umbrella." + +This describes the conversation which Mr. Sibley and I had. Mr. Sibley +talked, and I listened. He was a good talker, and I flatter myself that +I rather excel as a listener. On that occasion I did my best, for I knew +whom I was listening to. I was listening to the man who combined bold +and comprehensive grasp of thought, unerring foresight and sagacity, and +energy of action and power of accomplishment, in a degree not surpassed, +if it was equaled, among men. + +Some years before, Mr. Sibley had created the Western Union Telegraph +Company. At that time telegraphy was in a very depressed state. The +country was to a considerable extent occupied by local lines, chartered +under various State laws, and operated without concert. Four rival +companies, organized under the Morse, the Bain, the House, and the +Hughes patents, competed for the business. Telegraph stock was nearly +valueless. Hiram Sibley, a man of the people, a resident of an inland +city, of only moderate fortune, alone grasped the situation. He saw that +the nature of the business, and the demands of the country, alike +required that a single organization, in which all interests should be +combined, should cover the entire land with its network, by means of +which every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this vividly, +and realized it with the most intense earnestness of conviction. With +Mr. Sibley, to be convinced was to act; and so he set about the task of +carrying this vast scheme into execution. The result is well known. By +his immense energy, the magnetic power with which he infused his own +convictions into other minds, the direct, practical way in which he set +about the work, and his indomitable perseverance, Mr. Sibley attained at +last a phenomenal success. + +But he was not then telling me anything about this. He was telling me of +the construction of the telegraph line to the Pacific Coast. Here again +Mr. Sibley had seen that which was hidden from others. This case +differed from the former one in two important respects. Then Mr. Sibley +had been dependent on the aid and co-operation of many persons; and this +he had been able to secure. Now, he could not obtain help from a human +being; but he had become able to act independently of any assistance. + +He had made a careful study of the subject, in his thoroughly practical +way, and had become convinced that such a line was feasible, and would +be remunerative. At his instance a convention of telegraph men met in +the city of New York, to consider the project. The feeling in this +convention was extremely unfavorable to it. A committee reported against +it unanimously, on three grounds--the country was destitute of timber, +the line would be destroyed by the Indians, and if constructed and +maintained, it would not pay expenses. Mr. Sibley found himself alone. +An earnest appeal which he made from the report of the committee was +received with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and two +thousand miles of its breadth by bands of savages, who of course would +destroy the line as soon as it was put up, and where repairs would be +difficult and useless, even if the other objections to it were out of +the way, struck the members of the convention as so exquisitely +ludicrous that it seemed as if they would never be done laughing about +it. If Mr. Sibley had advocated a line to the moon, they would hardly +have seen in it greater evidence of lunacy. When he could be heard, he +rose again and said: "Gentlemen, you may laugh, but if I was not so old, +I would build the line myself." Upon this, of course, they laughed +louder than ever. As they laughed, he grew mad, and shouted: "Gentlemen, +I will bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon it +scouted the project as chimerical, and no capitalist would put a dollar +in it, Hiram Sibley built the line of telegraph to San Francisco, +risking in it all he had in the world. He set about the work with his +customary energy, all obstacles vanished, and the line was completed in +an incredibly short time. And from the day it was opened, it has proved +probably the most profitable line of telegraph that has ever been +constructed. There was the practicability, and there was the demand and +the business to be done, and yet no living man could see it, or could be +made to see it, except Hiram Sibley. "And to-day," he said, with honest +pride, "to-day in New York, men to whom I went almost on my knees for +help in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one." + +"But how about the Indians?" I asked. "Why," he replied, "we never had +any trouble from the Indians. I knew we wouldn't have. Men who supposed +I was such a fool as to go about this undertaking before that was all +settled didn't know me. No Indian ever harmed that line. The Indians are +the best friends we have got. You see, we taught the Indians the Great +Spirit was in that line; and what was more, we proved it to them. It +was, by all odds, the greatest medicine they ever saw. They fairly +worshiped it. No Indian ever dared to do it harm." + +"But," he added, "there was one thing I didn't count on. The border +ruffians in Missouri are as bad as anybody ever feared the Indians might +be. They have given us so much trouble that we are now building a line +around that State, through Iowa and Nebraska. We are obliged to do it." + +This opened another phase of the subject. The telegraph line to the +Pacific had a value beyond that which could be expressed in money. It +was perhaps the strongest of all the ties which bound California so +securely to the Union, in the dark days of its struggle for existence. +The secession element in Missouri recognized the importance of the line +in this respect, and were persistent in their efforts to destroy it. We +have seen by what means their purpose was thwarted. + +I have always felt that, among the countless evidences of the ordering +of Providence by which the war for the preservation of the Union was +signalized, not the least striking was the raising up of this remarkable +man, to accomplish alone, and in the very nick of time, a work which at +once became of such national importance. + +This is the man who has crowned his useful career, and shown again his +eminently practical character and wise foresight, by the endowment of +this College, which cannot fail to be a perennial source of benefit to +the country whose interests he has done so much to promote, and which +his remarkable sagacity and energy contributed so much to preserve. + +We have an excellent rule, followed by all successful designers of +machinery, which is, to make provision for the extreme case, for the +most severe test to which, under normal conditions, and so far as +practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than the +extreme demand are not likely to give trouble. I shall apply this +principle in addressing you to-day. In what I have to say, I shall speak +directly to the youngest and least advanced minds among my auditors. If +I am successful in making an exposition of my subject which shall be +plain to them, then it is evident that I need not concern myself about +being understood by the higher class men and the professors. + +The subject to which your attention is now invited is + + +THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES. + +This is a subject with which every one who expects to be concerned with +machinery, either as designer or constructor, ought to be familiar. The +principles which underlie it are very simple, but in order to be of use, +these need to be thoroughly understood. If they have once been mastered, +made familiar, incorporated into your intellectual being, so as to be +readily and naturally applied to every case as it arises, then you +occupy a high vantage ground. In this particular, at least, you will not +go about your work uncertainly, trying first this method and then that +one, or leaving errors to be disclosed when too late to remedy them. On +the contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what you +intend. + +Moreover, when you read discussions on any branch of this subject, you +will not receive these into unprepared minds, just as apt to admit error +as truth, and possessing no test by which to distinguish the one from +the other; but you will be able to form intelligent judgments with +respect to them. You will discover at once whether or not the writers +are anchored to the sure holding ground of sound principles. + +It is to be observed that I do not speak of balancing bodies, but of +balancing forces. Forces are the realities with which, as mechanical +engineers, you will have directly to deal, all through your lives. The +present discussion is limited also to those forces which are developed +in moving bodies, or by the motion of bodies. This limitation excludes +the force of gravity, which acts on all bodies alike, whether at rest or +in motion. It is, indeed, often desirable to neutralize the effect of +gravity on machinery. The methods of doing this are, however, obvious, +and I shall not further refer to them. + +Two very different forces, or manifestations of force, are developed by +the motion of bodies. These are + + +MOMENTUM AND CENTRIFUGAL FORCE. + +The first of these forces is exerted by every moving body, whatever the +nature of the path in which it is moving, and always in the direction of +its motion. The latter force is exerted only by bodies whose path is a +circle, or a curve of some form, about a central body or point, to which +it is held, and this force is always at right angles with the direction +of motion of the body. + +Respecting momentum, I wish only to call your attention to a single +fact, which will become of importance in the course of our discussion. +Experiments on falling bodies, as well as all experience, show that the +velocity of every moving body is the product of two factors, which must +combine to produce it. Those factors are force and distance. In order to +impart motion to the body, force must act through distance. These two +factors may be combined in any proportions whatever. The velocity +imparted to the body will vary as the square root of their product. +Thus, in the case of any given body, + + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. + +This table might be continued indefinitely. The product of the force +into the distance will always vary as the square of the final velocity +imparted. To arrest a given velocity, the same force, acting through the +same distance, or the same product of force into distance, is required +that was required to impart the velocity. + +The fundamental truth which I now wish to impress upon your minds is +that in order to impart velocity to a body, to develop the energy which +is possessed by a body in motion, force must act through distance. +Distance is a factor as essential as force. Infinite force could not +impart to a body the least velocity, could not develop the least energy, +without acting through distance. + +This exposition of the nature of momentum is sufficient for my present +purpose. I shall have occasion to apply it later on, and to describe the +methods of balancing this force, in those cases in which it becomes +necessary or desirable to do so. At present I will proceed to consider +the second of the forces, or manifestations of force, which are +developed in moving bodies--_centrifugal force_. + +This force presents its claims to attention in all bodies which revolve +about fixed centers, and sometimes these claims are presented with a +good deal of urgency. At the same time, there is probably no subject, +about which the ideas of men generally are more vague and confused. This +confusion is directly due to the vague manner in which the subject of +centrifugal force is treated, even by our best writers. As would then +naturally be expected, the definitions of it commonly found in our +handbooks are generally indefinite, or misleading, or even absolutely +untrue. + +Before we can intelligently consider the principles and methods of +balancing this force, we must get a correct conception of the nature of +the force itself. What, then, is centrifugal force? It is an extremely +simple thing; a very ordinary amount of mechanical intelligence is +sufficient to enable one to form a correct and clear idea of it. This +fact renders it all the more surprising that such inaccurate and +confused language should be employed in its definition. Respecting +writers, also, who use language with precision, and who are profound +masters of this subject, it must be said that, if it had been their +purpose to shroud centrifugal force in mystery, they could hardly have +accomplished this purpose more effectually than they have done, to minds +by whom it was not already well understood. + +Let us suppose a body to be moving in a circular path, around a center +to which it is firmly held; and let us, moreover, suppose the impelling +force, by which the body was put in motion, to have ceased; and, also, +that the body encounters no resistance to its motion. It is then, by our +supposition, moving in its circular path with a uniform velocity, +neither accelerated nor retarded. Under these conditions, what is the +force which is being exerted on this body? Clearly, there is only one +such force, and that is, the force which holds it to the center, and +compels it, in its uniform motion, to maintain a fixed distance from +this center. This is what is termed centripetal force. It is obvious, +that the centripetal force, which holds this revolving body _to_ the +center, is the only force which is being exerted upon it. + +Where, then, is the centrifugal force? Why, the fact is, there is not +any such thing. In the dynamical sense of the term "force," the sense in +which this term is always understood in ordinary speech, as something +tending to produce motion, and the direction of which determines the +direction in which motion of a body must take place, there is, I repeat, +no such thing as centrifugal force. + +There is, however, another sense in which the term "force" is employed, +which, in distinction from the above, is termed a statical sense. This +"statical force" is the force by the exertion of which a body keeps +still. It is the force of inertia--the resistance which all matter +opposes to a dynamical force exerted to put it in motion. This is the +sense in which the term "force" is employed in the expression +"centrifugal force." Is that all? you ask. Yes; that is all. + +I must explain to you how it is that a revolving body exerts this +resistance to being put in motion, when all the while it _is_ in motion, +with, according to our above supposition, a uniform velocity. The first +law of motion, so far as we now have occasion to employ it, is that a +body, when put in motion, moves in a straight line. This a moving body +always does, unless it is acted on by some force, other than its +impelling force, which deflects it, or turns it aside, from its direct +line of motion. A familiar example of this deflecting force is afforded +by the force of gravity, as it acts on a projectile. The projectile, +discharged at any angle of elevation, would move on in a straight line +forever, but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made to +fall, by the attraction of the earth; and so instead of a straight line +it describes a curve, known as the trajectory. + +Now a revolving body, also, has the same tendency to move in a straight +line. It would do so, if it were not continually deflected from this +line. Another force is constantly exerted upon it, compelling it, at +every successive point of its path, to leave the direct line of motion, +and move on a line which is everywhere equally distant from the center +to which it is held. If at any point the revolving body could get free, +and sometimes it does get free, it would move straight on, in a line +tangent to the circle at the point of its liberation. But if it cannot +get free, it is compelled to leave each new tangential direction, as +soon as it has taken it. + +This is illustrated in the above figure. The body, A, is supposed to be +revolving in the direction indicated by the arrow, in the circle, A B F +G, around the center, O, to which it is held by the cord, O A. At the +point, A, it is moving in the tangential direction, A D. It would +continue to move in this direction, did not the cord, O A, compel it to +move in the arc, A C. Should this cord break at the point, A, the body +would move; straight on toward D, with whatever velocity it had. + +You perceive now what centrifugal force is. This body is moving in the +direction, A D. The centripetal force, exerted through the cord, O A, +pulls it aside from this direction of motion. The body resists this +deflection, and this resistance is its centrifugal force. + +[Illustration: Fig. 1] + +Centrifugal force is, then, properly defined to be the disposition of a +revolving body to move in a straight line, and the resistance which such +a body opposes to being drawn aside from a straight line of motion. The +force which draws the revolving body continually to the center, or the +deflecting force, is called the centripetal force, and, aside from the +impelling and retarding forces which act in the direction of its motion, +the centripetal force is, dynamically speaking, the only force which is +exerted on the body. + +It is true, the resistance of the body furnishes the measure of the +centripetal force. That is, the centripetal force must be exerted in a +degree sufficient to overcome this resistance, if the body is to move in +the circular path. In this respect, however, this case does not differ +from every other case of the exertion of force. Force is always exerted +to overcome resistance: otherwise it could not be exerted. And the +resistance always furnishes the exact measure of the force. I wish to +make it entirely clear, that in the dynamical sense of the term "force," +there is no such thing as centrifugal force. The dynamical force, that +which produces motion, is the centripetal force, drawing the body +continually from the tangential direction, toward the center; and what +is termed centrifugal force is merely the resistance which the body +opposes to this deflection, _precisely like any other resistance to a +force_. + +The centripetal force is exerted on the radial line, as on the line, A +O, Fig. 1, at right angles with the direction in which the body is +moving; and draws it directly toward the center. It is, therefore, +necessary that the resistance to this force shall also be exerted on the +same line, in the opposite direction, or directly from the center. But +this resistance has not the least power or tendency to produce motion in +the direction in which it is exerted, any more than any other resistance +has. + +We have been supposing a body to be firmly held to the center, so as to +be compelled to revolve about it in a fixed path. But the bond which +holds it to the center may be elastic, and in that case, if the +centrifugal force is sufficient, the body will be drawn from the center, +stretching the elastic bond. It may be asked if this does not show +centrifugal force to be a force tending to produce motion from the +center. This question is answered by describing the action which really +takes place. The revolving body is now imperfectly deflected. The bond +is not strong enough to compel it to leave its direct line of motion, +and so it advances a certain distance along this tangential line. This +advance brings the body into a larger circle, and by this enlargement of +the circle, assuming the rate of revolution to be maintained, its +centrifugal force is proportionately increased. The deflecting power +exerted by the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct path; +and when the limit of its elasticity is reached, the deflecting bond +will be broken. If, however, the strength of the deflecting bond is +increased by its elongation in a more rapid ratio than the centrifugal +force is increased by the enlargement of the circle, then a point will +be reached in which the centripetal force will be sufficient to compel +the body to move again in the circular path. + +Sometimes the centripetal force is weak, and opportunity is afforded to +observe this action, and see its character exhibited. A common example +of weak centripetal force is the adhesion of water to the face of a +revolving grindstone. Here we see the deflecting force to become +insufficient to compel the drops of water longer to leave their direct +paths, and so these do not longer leave their direct paths, but move on +in those paths, with the velocity they have at the instant of leaving +the stone, flying off on tangential lines. + +If, however, a fluid be poured on the side of the revolving wheel near +the axis, it will move out to the rim on radial lines, as may be +observed on car wheels universally. The radial lines of black oil on +these wheels look very much as if centrifugal force actually did produce +motion, or had at least a very decided tendency to produce motion, in +the radial direction. This interesting action calls for explanation. In +this action the oil moves outward gradually, or by inconceivably minute +steps. Its adhesion being overcome in the least possible degree, it +moves in the same degree tangentially. In so doing it comes in contact +with a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it had +overcome the adhesion. Motion in the radial direction is the result of +these two actions, namely, leaving the first point of contact +tangentially and receiving an acceleration of its motion, so that this +shall be equal to that of the second point of contact. When we think +about the matter a little closely, we see that at the rim of the wheel +the oil has perhaps ten times the velocity of revolution which it had on +leaving the journal, and that the mystery to be explained really is, How +did it get that velocity, moving out on a radial line? Why was it not +left behind at the very first? Solely by reason of its forward +tangential motion. That is the answer. + +When writers who understand the subject talk about the centripetal and +centrifugal forces being different names for the same force, and about +equal action and reaction, and employ other confusing expressions, just +remember that all they really mean is to express the universal relation +between force and resistance. The expression "centrifugal force" is +itself so misleading, that it becomes especially important that the real +nature of this so-called force, or the sense in which the term "force" +is used in this expression, should be fully explained.[1] This force is +now seen to be merely the tendency of a revolving body to move in a +straight line, and the resistance which it opposes to being drawn aside +from that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see. + +[Footnote 1: I was led to study this subject in looking to see what had +become of my first permanent investment, a small venture, made about +thirty-five years ago, in the "Sawyer and Gwynne static pressure +engine." This was the high-sounding name of the Keely motor of that day, +an imposition made possible by the confused ideas prevalent on this very +subject of centrifugal force.] + +FIRST.--I have called your attention to the fact that the direction in +which the revolving body is deflected from the tangential line of motion +is toward the center, on the radial line, which forms a right angle with +the tangent on which the body is moving. The first question that +presents itself is this: What is the measure or amount of this +deflection? The answer is, this measure or amount is the versed sine of +the angle through which the body moves. + +Now, I suspect that some of you--some of those whom I am directly +addressing--may not know what the versed sine of an angle is; so I must +tell you. We will refer again to Fig. 1. In this figure, O A is one +radius of the circle in which the body A is revolving. O C is another +radius of this circle. These two radii include between them the angle A +O C. This angle is subtended by the arc A C. If from the point O we let +fall the line C E perpendicular to the radius O A, this line will divide +the radius O A into two parts, O E and E A. Now we have the three +interior lines, or the three lines within the circle, which are +fundamental in trigonometry. C E is the sine, O E is the cosine, and E A +is the versed sine of the angle A O C. Respecting these three lines +there are many things to be observed. I will call your attention to the +following only: + +_First_.--Their length is always less than the radius. The radius is +expressed by 1, or unity. So, these lines being less than unity, their +length is always expressed by decimals, which mean equal to such a +proportion of the radius. + +_Second_.--The cosine and the versed sine are together equal to the +radius, so that the versed sine is always 1, less the cosine. + +_Third_.--If I diminish the angle A O C, by moving the radius O C toward +O A, the sine C E diminishes rapidly, and the versed sine E A also +diminishes, but more slowly, while the cosine O E increases. This you +will see represented in the smaller angles shown in Fig. 2. If, finally, +I make O C to coincide with O A, the angle is obliterated, the sine and +the versed sine have both disappeared, and the cosine has become the +radius. + +_Fourth_.--If, on the contrary, I enlarge the angle A O C by moving the +radius O C toward O B, then the sine and the versed sine both increase, +and the cosine diminishes; and if, finally, I make O C coincide with O +B, then the cosine has disappeared, the sine has become the radius O B, +and the versed sine has become the radius O A, thus forming the two +sides inclosing the right angle A O B. The study of this explanation +will make you familiar with these important lines. The sine and the +cosine I shall have occasion to employ in the latter part of my lecture. +Now you know what the versed sine of an angle is, and are able to +observe in Fig. 1 that the versed sine A E, of the angle A O C, +represents in a general way the distance that the body A will be +deflected from the tangent A D toward the center O while describing the +arc A C. + +The same law of deflection is shown, in smaller angles, in Fig. 2. In +this figure, also, you observe in each of the angles A O B and A O C +that the deflection, from the tangential direction toward the center, of +a body moving in the arc A C is represented by the versed sine of the +angle. The tangent to the arc at A, from which this deflection is +measured, is omitted in this figure to avoid confusion. It is shown +sufficiently in Fig. 1. The angles in Fig. 2 are still pretty large +angles, being 12° and 24° respectively. These large angles are used for +convenience of illustration; but it should be explained that this law +does not really hold in them, as is evident, because the arc is longer +than the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent and +arc coincide, and approximately so for exceedingly small angles. + +[Illustration: Fig. 2] + +In reality, however, we have only to do with the case in which the arc +and the tangent do coincide, and in which the law that the deflection is +_equal to_ the versed sine of the angle is absolutely true. Here, in +observing this most familiar thing, we are, at a single step, taken to +that which is utterly beyond our comprehension. The angles we have to +consider disappear, not only from our sight, but even from our +conception. As in every other case when we push a physical investigation +to its limit, so here also, we find our power of thought transcended, +and ourselves in the presence of the infinite. + +We can discuss very small angles. We talk familiarly about the angle +which is subtended by 1" of arc. On Fig. 2, a short line is drawn near +to the radius O A'. The distance between O A' and this short line is 1° +of the arc A' B'. If we divide this distance by 3,600, we get 1" of arc. +The upper line of the Table of versed sines given below is the versed +sine of 1" of arc. It takes 1,296,000 of these angles to fill a circular +space. These are a great many angles, but they do not make a circle. +They make a polygon. If the radius of the circumscribed circle of this +polygon is 1,296,000 feet, which is nearly 213 geographical miles, each +one of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon would be +one-sixtieth of a geographical mile, or 101.46 feet. On the orbit of the +moon, at its mean distance from the earth, each of these straight sides +would be about 6,000 feet long. + +The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never can +reach the circle. When you swing a sling around your head, and feel the +uniform stress exerted on your hand through the cord, you are made aware +of an action which is entirely beyond the grasp of our minds and the +reach of our analysis. + +So always in practical operation that law is absolutely true which we +observe to be approximated to more and more nearly as we consider +smaller and smaller angles, that the versed sine of the angle is the +measure of its deflection from the straight line of motion, or the +measure of its fall toward the center, which takes place at every point +in the motion of a revolving body. + +Then, assuming the absolute truth of this law of deflection, we find +ourselves able to explain all the phenomena of centrifugal force, and to +compute its amount correctly in all cases. + +We have now advanced two steps. We have learned _the direction_ and _the +measure_ of the deflection, which a revolving body continually suffers, +and its resistance to which is termed centrifugal force. The direction +is toward the center, and the measure is the versed sine of the angle. + +SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that the +amount of centrifugal force exerted by a revolving body varies in four +ways. + +_First_.--Directly as the weight of the body. + +_Second_.--In a given circle of revolution, as the square of the speed +or of the number of revolutions per minute; which two expressions in +this case mean the same thing. + +_Third_.--With a given number of revolutions per minute, or a given +angular velocity[1] _directly_ as the radius of the circle; and + +_Fourth_.--With a given actual velocity, or speed in feet per minute, +_inversely_ as the radius of the circle. + +[Footnote 1: A revolving body is said to have the same angular velocity, +when it sweeps through equal angles in equal times. Its actual velocity +varies directly as the radius of the circle in which it is revolving.] + +Of course there is a reason for these laws. You are not to learn them by +rote, or to accept them on any authority. You are taught not to accept +any rule or formula on authority, but to demand the reason for it--to +give yourselves no rest until you know the why and wherefore, and +comprehend these fully. This is education, not cramming the mind with +mere facts and rules to be memorized, but drawing out the mental powers +into activity, strengthening them by use and exercise, and forming the +habit, and at the same time developing the power, of penetrating to the +reason of things. + +In this way only, you will be able to meet the requirement of a great +educator, who said: "I do not care to be told what a young man knows, +but what he can _do_." I wish here to add my grain to the weight of +instruction which you receive, line upon line, precept on precept, on +this subject. + +The reason for these laws of centrifugal force is an extremely simple +one. The first law, that this force varies directly as the weight of the +body, is of course obvious. We need not refer to this law any further. +The second, third, and fourth laws merely express the relative rates at +which a revolving body is deflected from the tangential direction of +motion, in each of the three cases described, and which cases embrace +all possible conditions. + +These three rates of deflection are exhibited in Fig. 2. An examination +of this figure will give you a clear understanding of them. Let us first +suppose a body to be revolving about the point, O, as a center, in a +circle of which A B C is an arc, and with a velocity which will carry it +from A to B in one second of time. Then in this time the body is +deflected from the tangential direction a distance equal to A D, the +versed sine of the angle A O B. Now let us suppose the velocity of this +body to be doubled in the same circle. In one second of time it moves +from A to C, and is deflected from the tangential direction of motion a +distance equal to A E, the versed sine of the angle, A O C. But A E is +four times A D. Here we see in a given circle of revolution the +deflection varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded. + +The following table will show, by comparison of the versed sines of very +small angles, the deflection in a given circle varying as the square of +the speed, when we penetrate to them, so nearly that the error is not +disclosed at the fifteenth place of decimals. + + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 + +You observe the deflection for 10" of arc is 100 times as great, and for +100" of arc is 10,000 times as great as it is for 1" of arc. So far as +is shown by the 15th place of decimals, the versed sine varies as the +square of the angle; or, in a given circle, the deflection, and so the +centrifugal force, of a revolving body varies as the square of the +speed. + +The reason for the third law is equally apparent on inspection of Fig. +2. It is obvious, that in the case of bodies making the same number of +revolutions in different circles, the deflection must vary directly as +the diameter of the circle, because for any given angle the versed sine +varies directly as the radius. Thus radius O A' is twice radius O A, and +so the versed sine of the arc A' B' is twice the versed sine of the arc +A B. Here, while the angular velocity is the same, the actual velocity +is doubled by increase in the diameter of the circle, and so the +deflection is doubled. This exhibits the general law, that with a given +angular velocity the centrifugal force varies directly as the radius or +diameter of the circle. + +We come now to the reason for the fourth law, that, with a given actual +velocity, the centrifugal force varies _inversely_ as the diameter of +the circle. If any of you ever revolved a weight at the end of a cord +with some velocity, and let the cord wind up, suppose around your hand, +without doing anything to accelerate the motion, then, while the circle +of revolution was growing smaller, the actual velocity continuing nearly +uniform, you have felt the continually increasing stress, and have +observed the increasing angular velocity, the two obviously increasing +in the same ratio. That is the operation or action which the fourth law +of centrifugal force expresses. An examination of this same figure (Fig. +2) will show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. If we +take the velocity A' B', double the velocity A B, and transfer it to the +smaller circle, we have the velocity A C. But the deflection has been +increasing as we have reduced the circle, and now with one half the +radius it is twice as great. It has increased in the same ratio in which +the angular velocity has increased. Thus we see the simple and necessary +nature of these laws. They merely express the different rates of +deflection of a revolving body in these different cases. + +THIRD.--We have a coefficient of centrifugal force, by which we are +enabled to compute the amount of this resistance of a revolving body to +deflection from a direct line of motion in all cases. This is that +coefficient. The centrifugal force of a body making _one_ revolution per +minute, in a circle of _one_ foot radius, is 0.000341 of the weight of +the body. + +According to the above laws, we have only to multiply this coefficient +by the square of the number of revolutions made by the body per minute, +and this product by the radius of the circle in feet, or in decimals of +a foot, and we have the centrifugal force, in terms of the weight of the +body. Multiplying this by the weight of the body in pounds, we have the +centrifugal force in pounds. + +Of course you want to know how this coefficient has been found out, and +how you can be sure it is correct. I will tell you a very simple way. +There are also mathematical methods of ascertaining this coefficient, +which your professors, if you ask them, will let you dig out for +yourselves. The way I am going to tell you I found out for myself, and +that, I assure you, is the only way to learn anything, so that it will +stick; and the more trouble the search gives you, the darker the way +seems, and the greater the degree of perseverance that is demanded, the +more you will appreciate the truth when you have found it, and the more +complete and permanent your possession of it will be. + +The explanation of this method may be a little more abstruse than the +explanations already given, but it is very simple and elegant when you +see it, and I fancy I can make it quite clear. I shall have to preface +it by the explanation of two simple laws. The first of these is, that a +body acted on by a constant force, so as to have its motion uniformly +accelerated, suppose in a straight line, moves through distances which +increase as the square of the time that the accelerating force continues +to be exerted. + +The necessary nature of this law, or rather the action of which this law +is the expression, is shown in Fig. 3. + +[Illustration: Fig. 3] + +Let the distances A B, B C, C D, and D E in this figure represent four +successive seconds of time. They may just as well be conceived to +represent any other equal units, however small. Seconds are taken only +for convenience. At the commencement of the first second, let a body +start from a state of rest at A, under the action of a constant force, +sufficient to move it in one second through a distance of one foot. This +distance also is taken only for convenience. At the end of this second, +the body will have acquired a velocity of two feet per second. This is +obvious because, in order to move through one foot in this second, the +body must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. Its +motion increased uniformly. Therefore, at the termination of the second +its velocity must have reached two feet per second. Let the triangle A B +F represent this accelerated motion, and the distance, of one foot, +moved through during the first second, and let the line B F represent +the velocity of two feet per second, acquired by the body at the end of +it. Now let us imagine the action of the accelerating force suddenly to +cease, and the body to move on merely with the velocity it has acquired. +During the next second it will move through two feet, as represented by +the square B F C I. But in fact, the action of the accelerating force +does not cease. This force continues to be exerted, and produces on the +body during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity accelerated +two additional feet per second, as represented by the line I G. So in +two seconds the body has moved through four feet. We may follow the +operation of this law as far as we choose. The figure shows it during +four seconds, or any other unit, of time, and also for any unit of +distance. Thus: + + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 + +So it is obvious that the distance moved through by a body whose motion +is uniformly accelerated increases as the square of the time. + +But, you are asking, what has all this to do with a revolving body? As +soon as your minds can be started from a state of rest, you will +perceive that it has everything to do with a revolving body. The +centripetal force, which acts upon a revolving body to draw it to the +center, is a constant force, and under it the revolving body must move +or be deflected through distances which increase as the squares of the +times, just as any body must do when acted on by a constant force. To +prove that a revolving body obeys this law, I have only to draw your +attention to Fig. 2. Let the equal arcs, A B and B C, in this figure +represent now equal times, as they will do in case of a body revolving +in this circle with a uniform velocity. The versed sines of the angles, +A O B and A O C, show that in the time, A C, the revolving body was +deflected four times as far from the tangent to the circle at A as it +was in the time, A B. So the deflection increased as the square of the +time. If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute angles, +absolutely so far as appears up to the fifteenth place of decimals, as +the square of the time. + +The standard from which all computations are made of the distances +passed through in given times by bodies whose motion is uniformly +accelerated, and from which the velocity acquired is computed when the +accelerating force is known, and the force is found when the velocity +acquired or the rate of acceleration is known, is the velocity of a body +falling to the earth. It has been established by experiment, that in +this latitude near the level of the sea, a falling body in one second +falls through a distance of 16.083 feet, and acquires a velocity of +32.166 feet per second; or, rather, that it would do so if it did not +meet the resistance of the atmosphere. In the case of a falling body, +its weight furnishes, first, the inertia, or the resistance to motion, +that has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the earth, or +the force exerted to overcome its resistance. Here, as in all possible +cases, the force and the resistance are identical with each other. The +above is, therefore, found in this way to be the rate at which the +motion of any body will be accelerated when it is acted on by a constant +force equal to its weight, and encounters no resistance. + +It follows that a revolving body, when moving uniformly in any circle at +a speed at which its deflection from a straight line of motion is such +that in one second this would amount to 16.083 feet, requires the +exertion of a centripetal force equal to its weight to produce such +deflection. The deflection varying as the square of the time, in 0.01 of +a second this deflection will be through a distance of 0.0016083 of a +foot. + +Now, at what speed must a body revolve, in a circle of one foot radius, +in order that in 0.01 of one second of time its deflection from a +tangential direction shall be 0.0016083 of a foot? This decimal is the +versed sine of the arc of 3°15', or of 3.25°. This angle is so small +that the departure from the law that the deflection is equal to the +versed sine of the angle is too slight to appear in our computation. +Therefore, the arc of 3.25° is the arc of a circle of one foot radius +through which a body must revolve in 0.01 of a second of time, in order +that the centripetal force, and so the centrifugal force, shall be equal +to its weight. At this rate of revolution, in one second the body will +revolve through 325°, which is at the rate of 54.166 revolutions per +minute. + +Now there remains only one question more to be answered. If at 54.166 +revolutions per minute the centrifugal force of a body is equal to its +weight, what will its centrifugal force be at one revolution per minute +in the same circle? + +To answer this question we have to employ the other extremely simple +law, which I said I must explain to you. It is this: The acceleration +and the force vary in a constant ratio with each other. Thus, let force +1 produce acceleration 1, then force 1 applied again will produce +acceleration 1 again, or, in other words, force 2 will produce +acceleration 2, and so on. This being so, and the amount of the +deflection varying as the squares of the speeds in the two cases, the +centrifugal force of a body making one revolution per minute in a circle +of + + 1² + one foot radius will be ---------- = 0.000341 + 54.166² + +--the coefficient of centrifugal force. + +There is another mode of making this computation, which is rather neater +and more expeditious than the above. A body making one revolution per +minute in a circle of one foot radius will in one second revolve through +an arc of 6°. The versed sine of this arc of 6° is 0.0054781046 of a +foot. This is, therefore, the distance through which a body revolving at +this rate will be deflected in one second. If it were acted on by a +force equal to its weight, it would be deflected through the distance of +16.083 feet in the same time. What is the deflecting force actually +exerted upon it? Of + + 0.0054781046 +course, it is ------------. + 16.083 + +This division gives 0.000341 of its weight as such deflecting force, the +same as before. + +In taking the versed sine of 6°, a minute error is involved, though not +one large enough to change the last figure in the above quotient. The +law of uniform acceleration does not quite hold when we come to an angle +so large as 6°. If closer accuracy is demanded, we can attain it, by +taking the versed sine for 1°, and multiplying this by 6². This gives as +a product 0.0054829728, which is a little larger than the versed sine of +6°. + +I hope I have now kept my promise, and made it clear how the coefficient +of centrifugal force may be found in this simple way. + +We have now learned several things about centrifugal force. Let me +recapitulate. We have learned: + +1st. The real nature of centrifugal force. That in the dynamical sense +of the term force, this is not a force at all: that it is not capable of +producing motion, that the force which is really exerted on a revolving +body is the centripetal force, and what we are taught to call +centrifugal force is nothing but the resistance which a revolving body +opposes to this force, precisely like any other resistance. + +2d. The direction of the deflection, to which the centrifugal force is +the resistance, which is straight to the center. + +3d. The measure of this deflection; the versed sine of the angle. + +4th. The reason of the laws of centrifugal force; that these laws merely +express the relative amount of the deflection, and so the amount of the +force required to produce the deflection, and of the resistance of the +revolving body to it, in all different cases. + +5th. That the deflection of a revolving body presents a case analogous +to that of uniformly accelerated motion, under the action of a constant +force, similar to that which is presented by falling bodies;[1] and +finally, + +6th. How to find the coefficient, by which the amount of centrifugal +force exerted in any case may be computed. + +[Footnote 1: A body revolving with a uniform velocity in a horizontal +plane would present the only case of uniformly accelerated motion that +is possible to be realized under actual conditions.] + +I now pass to some other features. + +_First_.--You will observe that, relatively to the center, a revolving +body, at any point in its revolution, is at rest. That is, it has no +motion, either from or toward the center, except that which is produced +by the action of the centripetal force. It has, therefore, this identity +also with a falling body, that it starts from a state of rest. This +brings us to a far more comprehensive definition of centrifugal force. +This is the resistance which a body opposes to being put in motion, at +any velocity acquired in any time, from a state of rest. Thus +centrifugal force reveals to us the measure of the inertia of matter. +This inertia may be demonstrated and exhibited by means of apparatus +constructed on this principle quite as accurately as it can be in any +other way. + +_Second_.--You will also observe the fact, that motion must be imparted +to a body gradually. As distance, _through_ which force can act, is +necessary to the impartation of velocity, so also time, _during_ which +force can act, is necessary to the same result. We do not know how +motion from a state of rest begins, any more than we know how a polygon +becomes a circle. But we do know that infinite force cannot impart +absolutely instantaneous motion to even the smallest body, or to a body +capable of opposing the least resistance. Time being an essential +element or factor in the impartation of velocity, if this factor be +omitted, the least resistance becomes infinite. + +We have a practical illustration of this truth in the explosion of +nitro-glycerine. If a small portion of this compound be exploded on the +surface of a granite bowlder, in the open air, the bowlder will be rent +into fragments. The explanation of this phenomenon common among the +laborers who are the most numerous witnesses of it, which you have +doubtless often heard, and which is accepted by ignorant minds without +further thought, is that the action of nitro-glycerine is downward. We +know that such an idea is absurd. + +The explosive force must be exerted in all directions equally. The real +explanation is, that the explosive action of nitro-glycerine is so +nearly instantaneous, that the resistance of the atmosphere is very +nearly equal to that of the rock; at any rate, is sufficient to cause +the rock to be broken up. The rock yields to the force very nearly as +readily as the atmosphere does. + +_Third_. An interesting solution is presented here of what is to many an +astronomical puzzle. When I was younger than I am now, I was greatly +troubled to understand how it could be that if the moon was always +falling to the earth, as the astronomers assured us it was, it should +never reach it, nor have its falling velocity accelerated. In popular +treatises on astronomy, such for example as that of Professor Newcomb, +this is explained by a diagram in which the tangential line is carried +out as in Fig. 1, and by showing that in falling from the point A to the +earth as a center, through distances increasing as the square of the +time, the moon, having the tangential velocity that it has, could never +get nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this long +tangential line has nothing to do with the motion of the moon, and while +we are compelled to assent to the demonstration, we want something +better. To my mind the better and more satisfactory explanation is found +in the fact that the moon is forever commencing to fall, and is +continually beginning to fall in a new direction. A revolving body, as +we have seen, never gets past that point, which is entirely beyond our +sight and our comprehension, of beginning to fall, before the direction +of its fall is changed. So, under the attraction of the earth, the moon +is forever leaving a new tangential direction of motion at the same +rate, without acceleration. + +(_To be continued_.) + + * * * * * + + + + +COMPRESSED AIR POWER SCHEMES. + +By J. STURGEON, Engineer of the Birmingham Compressed Air Power Company. + + +In the article on "Gas, Air, and Water Power" in the _Journal_ for Dec. +8 last, you state that you await with some curiosity my reply to certain +points in reference to the compressed air power schemes alluded to in +that article. I now, therefore, take the liberty of submitting to you +the arguments on my side of the question (which are substantially the +same as those I am submitting to Mr. Hewson, the Borough Engineer of +Leeds). The details and estimates for the Leeds scheme are not yet in a +forward enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system in +other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters of +detail. We have, however, recently succeeded in obtaining a suitable +place, and making arrangements for railway siding, water supply, etc.; +and we hope to be in a position to start early in the present year. + +I inclose (1) a tabulated summary of the estimates for Birmingham +divided into stages of 3,000 gross indicated horse power at a time; (2) +a statement showing the cost to consumers in terms of indicated horse +power and in different modes, more or less economical, of applying the +air power in the consumers' engines; (3) a tracing showing the method of +laying the mains; (4) a tracing showing the method of collecting the +meter records at the central station, by means of electric apparatus, +and ascertaining the exact amount of leakage. A short description of the +two latter would be as well. + +TABLE I.--_Showing the Progressive Development of the Compressed Air +System in stages of 3000 Indicated Horse Power (gross) at a Time, and +the Profits at each Stage_ + +_____________________________________________________________________________ + +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- + +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- + +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| £12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | £25,595 | £25,595 | £25,595 | £25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | £82,455 | £124,714 | £167,094 | £209,455 | £251,795 | +----------------------------------------------------------------------------- + +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| £6,405 | £7,855 | £9,305 | £10,955 | £12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | £12,080 | £18,508 | £24,944 | £31,589 | £38,096 | +----------------------------------------------------------------------------- + +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- + +TABLE II.--_Cost of Air Power in Terms of Indicated Horse Power_. + +Abbreviated column headings: + +Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per +Hour. + +Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet. + +Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per +Cent. + +Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet. + +Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per +Cent. + +Abbreviated row headings: + +CASE 1.--Where air at 45 lbs. pressure is re-heated to 320° Fahr., and +expanded to atmospheric pressure. + +CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to +212° Fahr., and expanded to atmospheric pressure. + +CASE 3.--Where air is used expansively without re-heating, whereby +intensely cold air is exhausted, and may be used for ice making, &c. + +CASE 4.--Where air is heated to 212° Fahr., and the terminal pressure is +11.3 lbs. above that of the atmosphere + +CASE 5.--Where the air is used without heating, and cut off at one-third +of the stroke, as in ordinary slide-valve engines + +CASE 6.--Where the air is used without re-heating and without expansion. + + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | £ s. d. | £ s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 0½| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 5½ | 9 10 5½| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 5½ | 9 1 10½| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ + +The great thing to guard against is leakage. If the pipes were simply +buried in the ground, it would be almost impossible to trace leakage, or +even to know of its existence. The income of the company might be +wasting away, and the loss never suspected until the quarterly returns +from the meters were obtained from the inspectors. Only then would it be +discovered that there must be a great leak (or it might be several +leaks) somewhere. But how would it be possible to trace them among 20 or +30 miles of buried pipes? We cannot break up the public streets. The +very existence of the concern depends upon (1) the _daily_ checking of +the meter returns, and comparison with the output from the air +compressors, so as to ascertain the amount of leakage; (2) facility for +tracing the locality of a leak; and (3) easy access to the mains with +the minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the pipes +are laid in concrete troughs, near the surface of the road, with +removable concrete covers strong enough to stand any overhead traffic. +At intervals there are junctions for service connections, with street +boxes and covers serving as inspection chambers. These chambers are also +provided over the ball-valves, which serve as stop-valves in case of +necessity, and are so arranged that in case of a serious breach in the +portion of main between any two of them, the rush of air to the breach +will blow them up to the corresponding seats and block off the broken +portion of main. The air space around the pipe in the concrete trough +will convey for a long distance the whistling noise of a leak; and the +inspectors, by listening at the inspection openings, will thus be +enabled to rapidly trace their way almost to the exact spot where there +is an escape. They have then only to remove the top surface of road +metal and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring from +the nearest street opening, the inspectors would know where to break +open the road to arrive at the probable locality of the leak. A very +slight leak can be heard a long way off by its peculiar whistling sound. + +[Illustration: COMPRESSED AIR POWER] + +The next point is to obtain a daily report of the condition of the mains +and the amount of leakage. It would be impracticable to employ an army +of meter inspectors to take the records daily from all the meters in the +district. We therefore adopt the method of electric signaling shown in +the second drawing. In the engineer's office, at the central station, is +fixed the dial shown in Fig. 1. Each consumer's meter is fitted with the +contact-making apparatus shown in Pig. 4, and in an enlarged form in +Figs. 5 and 6, by which a current is sent round the electro-magnet, D +(Fig. 1), attracting the armature, and drawing the disk forward +sufficiently for the roller at I to pass over the center of one of the +pins, and so drop in between that and the next pin, thus completing the +motion, and holding the disk steadily opposite the figure. This action +takes place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose one +meter should be moving very slowly, and so retaining contact for some +time, while other meters were working rapidly; the armature at D would +then be held up to the magnet by the prolonged contact maintained by the +slow moving meter, and so prevent the quick working meters from +actuating it; and they would therefore pass the contact points without +recording. A meter might also stop dead at the point of contact on +shutting off the air, and so hold up the armature; thus preventing +others from acting. To obviate this, we apply the disengaging apparatus +shown at L (Fig. 4). The contact maker works on the center, m, having an +armature on its opposite end. On contact being made, at the same time +that the magnet, D, is operated, the one at L is also operated, +attracting the armature, and throwing over the end of the contact maker, +l¹, on to the non-conducting side of the pin on the disk. Thus the whole +movement is rendered practically instantaneous, and the magnet at D is +set at liberty for the next operation. A resistance can be interposed at +L, if necessary, to regulate the period of the operation. The whole of +the meters work the common dial shown in Fig. 1, on which the gross +results only are recorded; and this is all we want to know in this way. +The action is so rapid, owing to the use of the magnetic disengaging +gear, that the chances of two or more meters making contact at the same +moment are rendered extremely small. Should such a thing happen, it +would not matter, as it is only approximate results that we require in +this case; and the error, if any, would add to the apparent amount of +leakage, and so be on the right side. Of course, the record of each +consumer's meter would be taken by the inspector at the end of every +quarter, in order to make out the bill; and the totals thus obtained +would be checked by the gross results indicated by the main dial. In +this way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected to an +extremely accurate measurement. At the end of the working day, the +engineer has merely to take down from the dial in his office the total +record of air measured to the consumers, also the output of air from the +compressors, which he ascertains by means of a continuous counter on the +engines, and the difference between the two will represent the loss. If +the loss is trifling, he will pass it over; if serious, he will send out +his inspectors to trace it. Thus there could be no long continued +leakage, misuse, or robbery of the air, without the company becoming +aware of the fact, and so being enabled to take measures to stop or +prevent it. The foregoing are absolutely essential adjuncts to any +scheme of public motive power supply by compressed air, without which we +should be working in the dark, and could never be sure whether the +company were losing or making money. With them, we know where we are and +what we are doing. + +Referring to the estimates given in Table I., I may explain that the +item of repairs and renewals covers 10 per cent. on boilers and gas +producers, 5 per cent. on engines, 5 per cent. on buildings, and 5 per +cent. on mains. Considering that the estimates include ample fitting +shops, with the best and most suitable tools, and that the wages list +includes a staff of men whose chief work would be to attend to repairs, +etc., I think the above allowances ample. Each item also includes 5 per +cent. for contingencies. + +I have commenced by giving all the preceding detail, in order to show +the groundwork on which I base the estimate of the cost of compressed +air power to consumers, in terms of indicated horse power per annum, as +given in Table II. I may say that, in estimating the engine power and +coal consumption, I have not, as in the original report, made purely +theoretical calculations, but have taken diagrams from engines in actual +use (although of somewhat smaller size than those intended to be +employed), and have worked out the results therefrom. It will, I hope, +be seen that, with all the safeguards we have provided, we may fairly +reckon upon having for sale the stated quantity of air produced by means +of the plant, as estimated, and at the specified annual cost; and that +therefore the statement of cost per indicated horse power per annum may +be fairly relied upon. Thus the cost of compressed air to the consumer, +based upon an _average_ charge of 5d. per 1,000 cubic feet, will vary +from £6 14s. per indicated horse power per annum to £18 13s. 3d., +according to circumstances and mode of application. + +A compressed air motor is an exceedingly simple machine--much simpler +than an ordinary steam engine. But the air may also be used in an +ordinary steam engine; and in this case it can be much simplified in +many details. Very little packing is needed, as there is no nuisance +from gland leakage; the friction is therefore very slight. Pistons and +glands are packed with soapstone, or other self-lubricating packing; and +no oil is required except for bearings, etc. The company will undertake +the periodical inspection and overhauling of engines supplied with their +power, all which is included in the estimates. The total cost to +consumers, with air at an average of 5d. per 1,000 cubic feet, may +therefore be fairly taken as follows: + + Min. Max. + Cost of air used £6 14 0½ £18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 12½ per cent. on + £10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + £8 19 0½ £20 18 3 + +The maximum case would apply only to direct acting engines, such as +Tangye pumps, air power hammers, etc., where the air is full on till the +end of the stroke, and where there is no expansion. The minimum given is +at the average rate of 5d. per 1,000 cubic feet; but as there will be +rates below this, according to a sliding scale, we may fairly take it +that the lowest charge will fall considerably below £6 per indicated +horse power per annum.--_Journal of Gas Lighting_. + + * * * * * + + + + +THE BERTHON COLLAPSIBLE CANOE. + + +An endeavor has often been made to construct a canoe that a person can +easily carry overland and put into the water without aid, and convert +into a sailboat. The system that we now call attention to is very well +contrived, very light, easily taken apart, and for some years past has +met with much favor. + +[Illustration: FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.] + +Mr. Berthon's canoes are made of impervious oil-skin. Form is given them +by two stiff wooden gunwales which are held in position by struts that +can be easily put in and taken out. The model shown in the figure is +covered with oiled canvas, and is provided with a double paddle and a +small sail. Fig. 2 represents it collapsed and being carried overland. + +[Illustration: FIG. 2.--THE SAME BEING CARRIED OVERLAND.] + +Mr. Berthon is manufacturing a still simpler style, which is provided +with two oars, as in an ordinary canoe. This model, which is much used +in England by fishermen and hunters, has for several years past been +employed in the French navy, in connection with movable defenses. At +present, every torpedo boat carries one or two of these canoes, each +composed of two independent halves that may be put into the water +separately or be joined together by an iron rod. + +These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure without +danger.[1]--_La Nature_. + +[Footnote 1: For detailed description see SUPPLEMENT, No. 84.] + + * * * * * + + + + +THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN STEAM +RAILROAD. + + +There was great excitement in Nürnberg on the 7th of December, 1835, on +which day the first German railroad was opened. The great square on +which the buildings of the Nürnberg and Furth "Ludwig's Road" stood, the +neighboring streets, and, in fact, the whole road between the two +cities, was filled with a crowd of people who flocked from far and near +to see the wonderful spectacle. For the first time, a railroad train +filled with passengers was to be drawn from Nürnberg to Furth by the +invisible power of the steam horse. At eight o'clock in the morning, the +civil and military authorities, etc., who took part in the celebration +were assembled on the square, and the gayly decorated train started off +to an accompaniment of music, cannonading, cheering, etc. Everything +passed off without an accident; the work was a success. The engraving in +the lower right-hand corner represents the engine and cars of this road. + +It will be plainly seen that such a revolution could not be accomplished +easily, and that much sacrifice and energy were required of the leaders +in the enterprise, prominent among whom was the merchant Johannes +Scharrer, who is known as the founder of the "Ludwig's Road." + +One would naturally suppose that such an undertaking would have met with +encouragement from the Bavarian Government, but this was not the case. +The starters of the enterprise met with opposition on every side; much +was written against it, and many comic pictures were drawn showing +accidents which would probably occur on the much talked of road. Two of +these pictures are shown in the accompanying large engraving, taken from +the _Illustrirte Zeitung_. As shown in the center picture, right hand, +it was expected by the railway opponents that trains running on tracks +at right angles must necessarily come in collision. If anything happened +to the engine, the passengers would have to get out and push the cars, +as shown at the left. + +[Illustration: JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF THE +OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--AT NURNBERG] + +Much difficulty was experienced in finding an engineer capable of +attending to the construction of the road; and at first it was thought +that it would be best to engage an Englishman, but finally Engineer +Denis, of Munich, was appointed. He had spent much time in England and +America studying the roads there, and carried on this work to the entire +satisfaction of the company. + +All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to be +given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first prize in +the competitive trials at Rainhill in 1829, delivered an engine of ten +horse power, which is still known in Nürnberg as "Der Englander." + +Fifty years have passed, and, as Johannes Scharrer predicted, the +Ludwig's Road has become a permanent institution, though it now forms +only a very small part of the network of railroads which covers every +portion of Germany. What changes have been made in railroads during +these fifty years! Compare the present locomotives with the one made by +Cugnot in 1770, shown in the upper left-hand cut, and with the work of +the pioneer Geo. Stephenson, who in 1825 constructed the first passenger +railroad in England, and who established a locomotive factory in +Newcastle in 1824. Geo. Stephenson was to his time what Mr. Borsig, +whose great works at Moabit now turn out from 200 to 250 locomotives a +year, is to our time. + +Truly, in this time there can be no better occasion for a celebration of +this kind than the fiftieth anniversary of the opening of the first +German railroad, which has lately been celebrated by Nürnberg and Furth. + +The lower left-hand view shows the locomotive De Witt Clinton, the third +one built in the United States for actual service, and the coaches. The +engine was built at the West Point Foundry, and was successfully tested +on the Mohawk and Hudson Railroad between Albany and Schenectady on Aug. +9, 1831. + + * * * * * + + + + +IMPROVED COAL ELEVATOR. + + +An illustration of a new coal elevator is herewith presented, which +presents advantages over any incline yet used, so that a short +description may be deemed interesting to those engaged in the coaling +and unloading of vessels. The pen sketch shows at a glance the +arrangement and space the elevator occupies, taking less ground to do +the same amount of work than any other mode heretofore adopted, and the +first cost of erecting is about the same as any other. + +When the expense of repairing damages caused by the ravages of winter is +taken into consideration, and no floats to pump out or tracks to wash +away, the advantages should be in favor of a substantial structure. + +The capacity of this hoist is to elevate 80,000 bushels in ten hours, at +less than one-half cent per bushel, and put coal in elevator, yard, or +shipping bins. + +[Illustration: IMPROVED COAL ELEVATOR.] + +The endless wire rope takes the cars out and returns them, dispensing +with the use of train riders. + +A floating elevator can distribute coal at any hatch on steam vessels, +as the coal has to be handled but once; the hoist depositing an empty +car where there is a loaded one in boat or barge, requiring no swing of +the vessel. + +Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor and +builder, and has them in use in the U.S. engineering service.--_Coal +Trade Journal_. + + * * * * * + + + + +STEEL-MAKING LADLES. + + +The practice of carrying melted cast iron direct from the blast furnace +to the Siemens hearth or the Bessemer converter saves both money and +time. It has rendered necessary the construction of special plant in the +form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson & +Co., of Preston, make the construction of these ladles a specialty, and +by their courtesy, says _The Engineer_, we are enabled to illustrate +four different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel foundry +work, and one of these for the Siemens-Martin process is illustrated by +Fig. 1. These ladles are made in sizes to take from five to fifteen ton +charges, or larger if required, and are mounted on a very strong +carriage with a backward and forward traversing motion, and tipping gear +for the ladle. The ladles are butt jointed, with internal cover strips, +and have a very strong band shrunk on hot about half way in the depth of +the ladle. This forms an abutment for supporting the ladle in the +gudgeon band, being secured to this last by latch bolts and cotters. The +gearing is made of cast steel, and there is a platform at one end for +the person operating the carriage or tipping the ladle. Stopper gear and +a handle are fitted to the ladles to regulate the flow of the molten +steel from the nozzle at the bottom. + +[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.] + +Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It +requires no description. Fig. 3 shows a tremendous ladle constructed for +the North-Eastern Steel Company, for carrying molten metal from the +blast furnace to the converter. It holds ten tons with ease. It is an +exceptionally strong structure. The carriage frame is constructed +throughout of 1 in. wrought-iron plated, and is made to suit the +ordinary 4 ft. 8½ in. railway gauge. The axle boxes are cast iron, +fitted with gun-metal steps. The wheels are made of forged iron, with +steel tires and axles. The carriage is provided with strong oak buffers, +planks, and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of ½ in. wrought-iron +plates, butt jointed, and double riveted butt straps. The trunnions and +flange couplings are of cast steel. The tipping gear, clearly shown in +the engraving, consists of a worm and wheel, both of steel, which can be +fixed on either side of the ladle as may be desired. From this it will +be seen that Messrs. Stevenson & Co. have made a thoroughly strong +structure in every respect, and one, therefore, that will commend itself +to most steel makers. We understand that these carriages are made in +various designs and sizes to meet special requirements. Thus, Fig. 4 +shows one of different design, made for a steel works in the North. This +is also a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great care +and honesty of purpose is required in making these structures. A +breakdown might any moment pour ten tons of molten metal on the ground, +with the most horrible results. + + * * * * * + + + + +APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE +SURFACE OF CONDUCTORS. + + +Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and +ingenious apparatus which permits of demonstrating that electricity +develops only on the surface of conductors. It consists (see figure) +essentially of a yellow-metal disk, M, fixed to an insulating support, +F, and carrying a concentric disk of ebonite, H. This latter receives a +hollow and closed hemisphere, J, of yellow metal, whose base has a +smaller diameter than that of the disk, H, and is perfectly insulated by +the latter. Another yellow-metal hemisphere, S, open below, is connected +with an insulating handle, G. The basal diameter of this second +hemisphere is such that when the latter is placed over J its edge rests +upon the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a hollow, +closed hemisphere that imprisons the hemisphere, J, which is likewise +hollow and closed, and perfectly insulated from the former. + +[Illustration] + +The shell, S, is provided internally with a curved yellow-metal spring, +whose point of attachment is at B, and whose free extremity is connected +with an ebonite button, K, which projects from the shell, S. By pressing +this button, a contact may be established between the external +hemisphere (formed of the pieces, S and M), and the internal one, J. As +soon as the button is left to itself, the spring again begins to bear +against the interior surface of S, and the two hemispheres are again +insulated. + +The experiment is performed in this wise: The shell, S, is removed. Then +a disk of steatite affixed to an insulating handle is rubbed for a few +instants with a fox's "brush," and held near J until a spark occurs. +Then the apparatus is grasped by the support, F, and an elder-pith ball +suspended by a flaxen thread from a good conducting support is brought +near J. The ball will be quickly repelled, and care must be taken that +it does not come into contact with J. After this the apparatus is placed +upon a table, the shell, S, is taken by its handle, G, and placed in the +position shown in the figure, and a momentary contact is established +between the two hemispheres by pressing the button, K. Then the shell, +S, is lifted, and the disk, M, is touched at the same time with the +other hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, thus +proving that all the electricity passed from J to S at the moment of +contact.--_La Lumiere Electrique_. + + * * * * * + + + + +THE COLSON TELEPHONE. + + +This apparatus has recently been the object of some experiments which +resulted in its being finally adopted in the army. We think that our +readers will read a description of it with interest. Its mode of +construction is based upon a theoretic conception of the lines of force, +which its inventor explains as follows in his Elementary Treatise on +Electricity: + +"To every position of the disk of a magnetic telephone with respect to +the poles of the magnet there corresponds a certain distribution of the +lines of force, which latter shift themselves when the disk is +vibrating. If the bobbin be met by these lines in motion, there will +develop in its wire a difference of potential that, according to +Faraday's law, will be proportional to their number. All things equal, +then, a telephone transmitter will be so much the more potent in +proportion as the lines set in motion by the vibrations of the disk and +meeting the bobbin wire are greater in number. In like manner, a +receiver will be so much the more potent in proportion as the lines of +force, set in motion by variations in the induced currents that are +traversing the bobbin and meeting the disk, are more numerous. It will +consequently be seen that, generally speaking, it is well to send as +large a number of lines of force as possible through the bobbin." + +[Illustration: FIG. 1.--THE COLSON TELEPHONE.] + +In order to obtain such a result, the thin tin-plate disk has to be +placed between the two poles of the magnet. The pole that carries the +fine wire bobbin acts at one side and in the center of the disk, while +the other is expanded at the extremity and acts upon the edge and the +other side. This pole is separated from the disk by a copper washer, and +the disk is thus wholly immersed in the magnetic field, and is traversed +by the lines of force radiatingly. + +This telephone is being constructed by Mr. De Branville, with the +greatest care, in the form of a transmitter (Fig. 2) and receiver (Fig. +3). At A may be seen the magnet with its central pole, P, and its +eccentric one, P'. This latter traverses the vibrating disk, M, through +a rubber-lined aperture and connects with the soft iron ring, F, that +forms the polar expansion. These pieces are inclosed in a nickelized +copper box provided with a screw cap, C. The resistance of both the +receiver and transmitter bobbin is 200 ohms. + +[Illustration: FIG. 2.--TRANSMITTER TAKEN APART.] + +The transmitter is 3½ in. in diameter, and is provided with a +re-enforcing mouthpiece. It is regulated by means of a screw which is +fixed in the bottom of the box, and which permits of varying the +distance between the disk and the core that forms the central pole of +the magnet. The regulation, when once effected, lasts indefinitely. The +regulation of the receiver, which is but 2¼ in. in diameter, is +performed once for all by the manufacturer. One of the advantages of +this telephone is that its regulation is permanent. Besides this, it +possesses remarkable power and clearness, and is accompanied with no +snuffling sounds, a fact doubtless owing to all the molecules of the +disk being immersed in the magnetic field, and to the actions of the two +poles occurring concentrically with the disk. As we have above said, +this apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used by +the artillery service in the organization of observatories from which to +watch firing, and the receiver is added to the apparatus pertaining to +military telegraphy. The two small receivers are held to the lens of the +operator by the latter's hat strap, while the transmitter is suspended +in a case supported by straps, with the mouthpieces near the face (Fig. +1). + +In the figure, the case is represented as open, so as to show the +transmitter. The empty compartment below is designed for the reception +and carriage of the receivers, straps, and flexible cords. This +arrangement permits of calling without the aid of special apparatus, and +it has also the advantage of giving entire freedom to the man on +observation, this being something that is indispensable in a large +number of cases. + +[Illustration: FIG. 3.--RECEIVER TAKEN APART.] + +In certain applications, of course, the receivers may be combined with a +microphone; yet on an aerial as well as on a subterranean line the +transmitter produces effects which, as regards intensity and clearness, +are comparable with those of a pile transmitter. + +Stations wholly magnetic may be established by adding to the transmitter +and two receivers a Sieur phonic call, which will actuate them +powerfully, and cause them to produce a noise loud enough for a call. It +would be interesting to try this telephone on a city line, and to a +great distance on those telegraph lines that are provided with the Van +Rysselberghe system. Excellent results would certainly be obtained, for, +as we have recently been enabled to ascertain, the voice has a +remarkable intensity in this telephone, while at the same time perfectly +preserving its quality.--_La Nature_. + + * * * * * + +[NATURE.] + + + + +THE MELDOMETER. + + +The apparatus which I propose to call by the above name +([mu][epsilon][lambda][delta][omega], to melt) consists of an adjunct to +the mineralogical microscope, whereby the melting-points of minerals may +be compared or approximately determined and their behavior watched at +high temperatures either alone or in the presence of reagents. + +As I now use it, it consists of a narrow ribbon of platinum (2 mm. wide) +arranged to traverse the field of the microscope. The ribbon, clamped in +two brass clamps so as to be readily renewable, passes bridgewise over a +little scooped-out hollow in a disk of ebony (4 cm. diam.). The clamps +also take wires from a battery (3 Groves cells); and an adjustable +resistance being placed in circuit, the strip can be thus raised in +temperature up to the melting-point of platinum. + +The disk being placed on the stage of the microscope the platinum strip +is brought into the field of a 1" objective, protected by a glass slip +from the radiant heat. The observer is sheltered from the intense light +at high temperatures by a wedge of tinted glass, which further can be +used in photometrically estimating the temperature by using it to obtain +extinction of the field. Once for all approximate estimations of the +temperature of the field might be made in terms of the resistance of the +platinum strip, the variation of such resistance with rise of +temperature being known. Such observations being made on a suitably +protected strip might be compared with the wedge readings, the latter +being then used for ready determinations. Want of time has hindered me +from making such observations up to this. + +The mineral to be experimented on is placed in small fragments near the +center of the platinum ribbon, and closely watched while the current is +increased, till the melting-point of the substance is apparent. Up to +the present I have only used it comparatively, laying fragments of +different fusibilities near the specimen. In this way I have melted +beryl, orthoclase, and quartz. I was much surprised to find the last +mineral melt below the melting-point of platinum. I have, however, by me +as I write, a fragment, formerly clear rock-crystal, so completely fused +that between crossed Nicols it behaves as if an amorphous body, save in +the very center where a speck of flashing color reveals the remains of +molecular symmetry. Bubbles have formed in the surrounding glass. + +Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way. + +Topaz whitens to a milky glass--apparently decomposing, throwing out +filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot platinum, +causes rings of color to appear round the specimen. I have now been +using the apparatus for nearly a month, and in its earliest days it led +me right in the diagnosis of a microscopical mineral, iolite, not before +found in our Irish granite, I think. The unlooked-for characters of the +mineral, coupled with the extreme minuteness of the crystals, led me +previously astray, until my meldometer fixed its fusibility for me as +far above the suspected bodies. + +Carbon slips were at first used, as I was unaware of the capabilities of +platinum. + +A form of the apparatus adapted, at Prof. Fitzgerald's suggestion, to +fit into the lantern for projection on the screen has been made for me +by Yeates. In this form the heated conductor passes both below and above +the specimen, which is regarded from a horizontal direction. + +J. JOLY. + +Physical Laboratory, Trinity College, Dublin. + + * * * * * + +[AMERICAN ANNALS OF THE DEAF AND DUMB.] + + + + +TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF DEAF-MUTES. + + +Progress in electrical science is daily causing the world to open its +eyes in wonder and the scientist to enlarge his hopes for yet greater +achievements. The practical uses to which this subtile fluid, +electricity, is being put are causing changes to be made in time-tested +methods of doing things in domestic, scientific, and business circles, +and the time has passed when startling propositions to accomplish this +or that by the assistance of electricity are dismissed with incredulous +smiles. This being the case, no surprise need follow the announcement of +a device to facilitate the imparting of instruction to deaf children +which calls into requisition some service from electricity. + +The sense of touch is the direct medium contemplated, and it is intended +to convey, with accuracy and rapidity, messages from the operator (the +teacher) to the whole class simultaneously by electrical +transmission.[1] + +[Footnote 1: By the same means two deaf-mutes, miles apart, might +converse with each other, and the greatest difficulty in the way of a +deaf-mute becoming a telegraph operator, that of receiving messages, +would be removed. The latter possibilities are incidentally mentioned +merely as of scientific interest, and not because of their immediate +practical value. The first mentioned use to which the device may be +applied is the one considered by the writer as possibly of practical +value, the consideration of which suggested the appliance to him.] + +An alphabet is formed upon the palm of the left hand and the inner side +of the fingers, as shown by the accompanying cut, which, to those +becoming familiar with it, requires but a touch upon a certain point of +the hand to indicate a certain letter of the alphabet. + +A rapid succession of touches upon various points of the hand is all +that is necessary in spelling a sentence. The left hand is the one upon +which the imaginary alphabet is formed, merely to leave the right hand +free to operate without change of position when two persons only are +conversing face to face. + +The formation of the alphabet here figured is on the same principle as +one invented by George Dalgarno, a Scottish schoolmaster, in the year +1680, a cut of which maybe seen on page 19 of vol. ix. of the _Annals_, +accompanying the reprint of a work entitled "_Didascalocophus_." +Dalgarno's idea could only have been an alphabet to be used in +conversation between two persons _tête à tête_, and--except to a limited +extent in the Horace Mann School and in Professor Bell's teaching--has +not come into service in the instruction of deaf-mutes or as a means of +conversation. There seems to have been no special design or system in +the arrangement of the alphabet into groups of letters oftenest +appearing together, and in several instances the proximity would +seriously interfere with distinct spelling; for instance, the group "u," +"y," "g," is formed upon the extreme joint of the little finger. The +slight discoverable system that seems to attach to his arrangement of +the letters is the placing of the vowels in order upon the points of the +fingers successively, beginning with the thumb, intended, as we suppose, +to be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly as +another. If any arrangement has advantage over another, we consider it +the one which has so grouped the letters as to admit of an increased +rapidity of manipulation. The arrangement of the above alphabet, it is +believed, does admit of this. Yet it is not claimed that it is as +perfect as the test of actual use may yet make it. Improvements in the +arrangement will, doubtless, suggest themselves, when the alterations +can be made with little need of affecting the principle. + +In order to transmit a message by this alphabet, the following described +appliance is suggested: A matrix of cast iron, or made of any suitable +material, into which the person receiving the message (the pupil) places +his left hand, palm down, is fixed to the table or desk. The matrix, +fitting the hand, has twenty-six holes in it, corresponding in position +to the points upon the hand assigned to the different letters of the +alphabet. In these holes are small styles, or sharp points, which are so +placed as but slightly to touch the hand. Connected with each style is a +short line of wire, the other end of which is connected with a principal +wire leading to the desk of the operator (the teacher), and there so +arranged as to admit of opening and closing the circuit of an electric +current at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric impulses, +intended to act mechanically upon all the styles connected with it. By +these impulses, produced by the will of the sender, the styles are +driven upward with a quick motion, but with only sufficient force to be +felt and located upon the hand by the recipient. Twenty-six of these +principal or primary wires are run from the teacher's desk (there +connected with as many buttons) under the floor along the line of +pupils' desks. From each matrix upon the desk run twenty-six secondary +wires down to and severally connecting with the twenty-six primary wires +under the floor. The whole system of wires is incased so as to be out of +sight and possibility of contact with foreign substances. The keys or +buttons upon the desk of the teacher are systematically arranged, +somewhat after the order of those of the type writer, which allows the +use of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," "c," +etc., to "z," and an electric current over the primary wire running from +a certain button (say the one labeled "a") affects only those secondary +wires connected with the styles that, when excited, produce upon the +particular spot of the hands of the receivers the tactile impression to +be interpreted as "a." And so, whenever the sender touches any of the +buttons on his desk, immediately each member of the class feels upon the +palm of his hand the impression meant to be conveyed. The contrivance +will admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric bell. +It was first thought of conveying the impressions directly by slight +electric shocks, without the intervention of further mechanical +apparatus, but owing to a doubt as to the physical effect that might be +produced upon the persons receiving, and as to whether the nerves might +not in time become partly paralyzed or so inured to the effect as to +require a stronger and stronger current, that idea was abandoned, and +the one described adopted. A diagram of the apparatus was submitted to a +skillful electrical engineer and machinist of Hartford, who gave as his +opinion that the scheme was entirely feasible, and that a simple and +comparatively inexpensive mechanism would produce the desired result. + +[Illustration: TOUCH TRANSMISSION BY ELECTRICITY.] + +The matter now to consider, and the one of greater interest to the +teacher of deaf children, is, Of what utility can the device be in the +instruction of deaf-mutes? What advantage is there, not found in the +prevailing methods of communication with the deaf, i.e., by gestures, +dactylology, speech and speech-reading, and writing? + +I. The language of gestures, first systematized and applied to the +conveying of ideas to the deaf by the Abbe de l'Epee during the latter +part of the last century, has been, in America, so developed and +improved upon by Gallaudet, Peet, and their successors, as to leave but +little else to be desired for the purpose for which it was intended. The +rapidity and ease with which ideas can be expressed and understood by +this "language" will never cease to be interesting and wonderful, and +its value to the deaf can never fail of being appreciated by those +familiar with it. But the genius of the language of signs is such as to +be in itself of very little, if any, direct assistance in the +acquisition of syntactical language, owing to the diversity in the order +of construction existing between the English language and the language +of signs. Sundry attempts have been made to enforce upon the +sign-language conformity to the English order, but they have, in all +cases known to the writer, been attended with failure. The sign-language +is as immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given with +great success upon the basis of the sign-language. But in all such +exercises there must be a translation from one language to the other. +The desideratum still exists of an increased percentage of pupils +leaving our schools for the deaf, possessing a facility of expression in +English vernacular. This want has been long felt, and endeavoring to +find a reason for the confessedly low percentage, the sign-language has +been too often unjustly accused. It is only when the sign-language is +abused that its merit as a means of instruction degenerates. The most +ardent admirers of a proper use of signs are free to admit that any +excessive use by the pupils, which takes away all opportunities to +express themselves in English, is detrimental to rapid progress in +English expression. + +II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as one +of the elements of the American or eclectic method. This advantage, +however, is not of so great importance as to outweigh the disadvantages +when, as has honestly been attempted, it asserts its independence of +other methods. Very few persons indeed, even after long practice, become +sufficiently skillful in spelling on the fingers to approximate the +rapidity of speech. But were it possible for all to become rapid +spellers, another very important requisite is necessary before the +system could be a perfect one, that is, the ability to _read_ rapid +spelling. The number of persons capable of reading the fingers beyond a +moderate degree of rapidity is still less than the number able to spell +rapidly. While it is physically possible to follow rapid spelling for +twenty or thirty minutes, it can scarcely be followed longer than that. +So long as this is true, dactylology can hardly claim to be more than +one of the _elements_ of a system of instruction for the deaf. + +III. Articulate speech is another of the elements of the eclectic +method, employed with success inversely commensurate with the degree of +deficiency arising from deafness. Where the English order is already +fixed in his mind, and he has at an early period of life habitually used +it, there is comparatively little difficulty in instructing the deaf +child by speech, especially if he have a quick eye and bright intellect. +But the number so favored is a small percentage of the great body of +deaf-mutes whom we are called upon to educate. When it is used as a +_sole_ means of educating the deaf as a class its inability to stand +alone is as painfully evident as that of any of the other component +parts of the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to what +a word is if spelled slowly enough, and if its meaning has been learned. +This cannot be said of speech. Between many words there is not, when +uttered, the slightest visible distinction. Between a greater number of +others the distinction is so slight as to cause an exceedingly nervous +hesitation before a guess can be given. Too great an imposition is put +upon the eye to expect it to follow unaided the extremely circumscribed +gestures of the organs of speech visible in ordinary speaking. The ear +is perfection as an interpreter of speech to the brain. It cannot +correctly be said that it is _more_ than perfection. It is known that +the ear, in the interpretation of vocal sounds, is capable of +distinguishing as many as thirty-five sounds per second (and oftentimes +more), and to follow a speaker speaking at the rate of more than two +hundred words per minute. If this be perfection, can we expect the _eye_ +of ordinary mortal to reach it? Is there wonder that the task is a +discouraging one for the deaf child? + +But it has been asserted that while a large percentage (practically all) +of the deaf _can_, by a great amount of painstaking and practice, become +speech readers in some small degree, a relative degree of facility in +articulation is not nearly so attainable. As to the accuracy of this +view, the writer cannot venture an opinion. Judging from the average +congenital deaf-mute who has had special instruction in speech, it can +safely be asserted that their speech is laborious, and far, very far, +from being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that as an +unaided means of instruction it cannot be a success, for English neither +understood when spoken, nor spoken by the pupil, cannot but remain a +foreign language, requiring to pass through some other form of +translation before it becomes intelligible. + +There are the same obstacles in the use of the written or printed word +as have been mentioned in connection with dactylology, namely, lack of +rapidity in conveying impressions through the medium of the English +sentence. + +I have thus hastily reviewed the several means which teachers generally +are employing to impart the use of English to deaf pupils, for the +purpose of showing a common difficulty. The many virtues of each have +been left unnoticed, as of no pertinence to this article. + +The device suggested at the beginning of this paper, claiming to be +nothing more than a school room appliance intended to supplement the +existing means for giving a knowledge and practice of English to the +deaf, employs as its interpreter a different sense from the one +universally used. The sense of sight is the sole dependence of the deaf +child. Signs, dactylology, speech reading, and the written and printed +word are all dependent upon the eye for their value as educational +instruments. It is evident that of the two senses, sight and touch, if +but one could be employed, the choice of sight as the one best adapted +for the greatest number of purposes is an intelligent one; but, as the +choice is not limited, the question arises whether, in recognizing the +superior adaptability to our purpose of the one, we do not lose sight of +a possibly important, though secondary, function in the other. If sight +were all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we acquire +our vernacular is of divine, and not of human, origin, and the senses +designed for special purposes are not interchangeable without loss. The +theory that the loss of a certain sense is nearly, if not quite, +compensated for by increased acuteness of the remaining ones has been +exploded. Such a theory accuses, in substance, the Maker of creating +something needless, and is repugnant to the conceptions we have of the +Supreme Being. When one sense is absent, the remaining senses, in order +to equalize the loss, have imposed upon them an unusual amount of +activity, from which arises skill and dexterity, and by which the loss +of the other sense is in some measure alleviated, but not supplied. No +_additional_ power is given to the eye after the loss of the sense of +hearing other than it might have acquired with the same amount of +practice while both faculties were active. The fact, however, that the +senses, in performing their proper functions, are not overtaxed, and are +therefore, in cases of emergency, capable of being extended so as to +perform, in various degrees, additional service, is one of the wise +providences of God, and to this fact is due the possibility of whatever +of success is attained in the work of educating the deaf, as well as the +blind. + +In the case of the blind, the sense of touch is called into increased +activity by the absence of the lost sense; while in the case of the +deaf, sight is asked to do this additional service. A blind person's +education is received principally through the _two_ senses of hearing +and touch. Neither of these faculties is so sensible to fatigue by +excessive use as is the sense of sight, and yet the eye has, in every +system of instruction applied to the deaf, been the sole medium. In no +case known to the writer, excepting in the celebrated case of Laura +Bridgman and a few others laboring under the double affliction of +deafness and blindness, has the sense of touch been employed as a means +of instruction.[1] + +[Footnote 1: This article was written before Professor Bell had made his +interesting experiments with his "parents' class" of a touch alphabet, +to be used upon the pupil's shoulder in connection with the oral +teaching.--E.A.F.] + +Not taking into account the large percentage of myopes among the deaf, +we believe there are other cogent reasons why, if found practicable, the +use of the sense of touch may become an important element in our +eclectic system of teaching. We should reckon it of considerable +importance if it were ascertained that a portion of the same work now +performed by the eye could be accomplished equally as well through +feeling, thereby relieving the eye of some of its onerous duties. + +We see no good reason why such accomplishment may not be wrought. If, +perchance, it were discovered that a certain portion could be performed +in a more efficient manner, its value would thus be further enhanced. + +In theory and practice, the teacher of language to the deaf, by whatever +method, endeavors to present to the eye of the child as many completed +sentences as are nominally addressed to the ear--having them "caught" by +the eye and reproduced with as frequent recurrence as is ordinarily done +by the child of normal faculties. + +In our hasty review of the methods now in use we noted the inability to +approximate this desirable process as a common difficulty. The facility +now ordinarily attained in the manipulation of the type writer, and the +speed said to have been reached by Professor Bell and a private pupil of +his by the Dalgarno touch alphabet, when we consider the possibility of +a less complex mechanism in the one case and a more systematic grouping +of the alphabet in the other, would lead us to expect a more rapid means +of communication than is ordinarily acquired by dactylology, speech (by +the deaf), or writing. Then the ability to receive the communication +rapidly by the sense of feeling will be far greater. No part of the body +except the point of the tongue is as sensible to touch as the tips of +the fingers and the palm of the hand. Tactile discrimination is so acute +as to be able to interpret to the brain significant impressions produced +in very rapid succession. Added to this advantage is the greater one of +the absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the tympanum of +the ear. To sum up, then, the advantages of the device we find-- + +First. A more rapid means of communication with the deaf by syntactic +language, admitting of a greater amount of practice similar to that +received through the ear by normal children. + +Second. Ability to receive this rapid communication for a longer +duration and without ocular strain. + +Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender. + +Fourth. In articulation and speech-reading instruction, the power to +assist a class without distracting the attention of the eye from the +vocal organs of the teacher. + +Fifth. Freedom of the right hand of the pupil to make instantaneous +reproduction in writing of the matter being received through the sense +of feeling, thereby opening the way for a valuable class exercise. + +Sixth. The possible mental stimulus that accompanies the mastery of a +new language, and the consequent ability to receive known ideas through +a new medium. + +Seventh. A fresh variety of class exercises made possible. + +The writer firmly believes in the good that exists in all methods that +are, or are to be; in the interdependence rather than the independence +of all methods; and in all school-room appliances tending to supplement +or expedite the labors of the teacher, whether they are made of +materials delved from the earth or snatched from the clouds. + +S. TEFFT WALKER, + +_Superintendent of the Kansas Institution, Olathe, Kans_. + + * * * * * + + + + +WATER GAS. + +THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON REDUCING AGENTS. + +By B.H. THWAITE. + + +In order to approximately ascertain the relative reducing action of +water gas, carbon monoxide, and superheated steam on iron ore, the +author decided to have carried out the following experiments, which were +conducted by Mr. Carl J. Sandahl, of Stockholm, who also carried out the +analyses. The ore used was from Bilbao, and known as the Ruby Mine, and +was a good average hematite. The carbonaceous material was the Trimsaran +South Wales anthracite, and contained about 90 per cent. of carbon. + +A small experimental furnace was constructed of the form shown by +illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the base, +and gradually swelling to 2 ft. 9 in. at the top, built entirely of +fireclay bricks. Two refractory tubes, 2 in. square internally, and the +height of the furnace, were used for the double purpose of producing the +gas and reducing the ore. + +The end of the lower tube rested on a fireclay ladle nozzle, and was +properly jointed with fireclay; through this nozzle the steam or air was +supplied to the inside of the refractory tubes. In each experiment the +ore and fuel were raised to the temperature "of from 1,800 to 2,200 deg. +Fahr." by means of an external fire of anthracite. Great care was taken +to prevent the contact of the solid carbonaceous fuel with the ore. In +each experiment in which steam was used, the latter was supplied at a +temperature equivalent to 35 lb. to the square inch. + +The air for producing the carbon monoxide (CO) gas was used at the +temperature of the atmosphere. As near as possible, the same conditions +were obtained in each experiment, and the equivalent weight of air was +sent through the carbon to generate the same weight of CO as that +generated when steam was used for the production of water gas. + +[Illustration] + +_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled +with ore broken to the size of nuts. The tube, A, was heated to about +2,000 deg. Fahr., the upper one to about 1,500 deg. + +NOTE.--In this experiment, part of the steam was dissociated in passing +through the turned-up end of the steam supply pipe, which became very +hot, and the steam would form with the iron the magnetic oxide +(Fe_{3}O_{4}). The reduction would doubtless be due to this +dissociation. The pieces of ore found on lowest end of the tube, A, were +dark colored and semi-fused; part of one of these pieces was crushed +fine, and tested; see column I. The remainder of these black pieces was +mixed with the rest of the ore contained in tube, A, and ground and +tested; see column II. The ore in upper tube was all broken up together +and tested; see column III. When finely crushed, the color of No. I. was +bluish black; No. II., a shade darker red; No. III., a little darker +than the natural color of the ore. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- + +_Second Experiment, Water Gas_.--The tube, A, was filled with small +pieces of anthracite, and heated until all the volatile matter had been +expelled. The tube, B, was then placed in tube, A, the joint being made +with fireclay, and to prevent the steam from carrying small particles of +solid carbon into ore in the upper tube, the anthracite was divided from +the ore by means of a piece of fine wire gauze. The steam at a pressure +of about 35 lb. to the square inch was passed through the anthracite. +The tube, A, was heated to white heat, the tube, B, at its lower end to +bright red, the top to cherry red. + +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ + +_Four Samples were Tested_.--I. The bottom layer, 1¼ in. thick; the +color of ore quite black, with small particles of reduced spongy +metallic iron. II. Layer above I., 4¼ in. thick; the color was also +black, but showed a little purple tint. III. Layer above II., 5 in. +thick; purple red color. IV. Layer above III., ore a red color. The +analyses gave: + +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- + +NOTE.--All the carbon dioxide (CO_{2}) occurring in the ore as calcic +carbonate was expelled. + +_Third Experiment, Carbon monoxide_ (CO).--The tube A was filled with +anthracite in the manner described for the second experiment, and heated +to drive off the volatile matter, before the ore was placed in the upper +tube, B, and the anthracite was divided from the ore by means of a piece +of fine wire gauze. The lower tube, A, was heated to the temperature of +white heat, the upper one, B, to a temperature of bright red. I. Layer, +1 in. thick from the bottom; ore dark brownish colored. II. Layer 4 in. +thick above I.; ore reddish brown. III. Layer 11 in. thick above II.; +ore red color. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- + +NOTE.--The carbon monoxide (CO) had failed to remove from the ore the +carbon dioxide existing as calcic carbonate. The summary of experiments +in the following table appears to show that the water gas is a more +powerful reducing agent than CO in proportion to the ratio of as + + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 + +Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just now +constructing large experimental plant in which water gas will be used as +the reducing agent. This plant would have been at work before this but +for some defects in the valvular arrangements, which will be entirely +removed in the new modifications of the plant. + + * * * * * + + + + +ANTISEPTIC MOUTH WASH. + + +Where an antiseptic mouth wash is needed, Mr. Sewill prescribes the use +of perchloride of mercury in the following form: One grain of the +perchloride and 1 grain of chloride of ammonium to be dissolved in 1 oz. +of eau de Cologne or tincture of lemons, and a teaspoonful of the +solution to be mixed with two-thirds of a wineglassful of water, making +a proportion of about 1 of perchloride in 5,000 parts.--_Chemist and +Druggist_. + + * * * * * + + + + +ANNATTO. + +[Footnote: Read at an evening meeting of the North British Branch of the +Pharmaceutical Society, January 21.] + +By WILLIAM LAWSON. + + +The subject which I have the honor to bring shortly before your notice +this evening is one that formed the basis of some instructive remarks by +Dr. Redwood in November, 1855, and also of a paper by Dr. Hassall, read +before the Society in London in January, 1856, which latter gave rise to +an animated discussion. The work detailed below was well in hand when +Mr. MacEwan drew my attention to these and kindly supplied me with the +volume containing reports of them. Unfortunately, they deal principally +with the adulterations, while I was more particularly desirous to learn +the composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. Within +the last few years it was one of the articles in considerable demand in +this part of the country; now it is seldom inquired for. This, +certainly, is not because butter coloring has ceased to be employed, and +hence the reason for regretting that the percentage of resin was not +dealt with in the articles referred to, so that a comparison could have +been made between the commercial annatto of that period and that which +exists now. In case some may not be in possession of literature bearing +on it--which, by the way, is very meager--it may not be out of place to +quote some short details as to its source, the processes for obtaining +it, the composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has more +interest for the country than for the town druggist, still, I trust it +will have points of interest for both. + +Annatto is the coloring matter derived from the seeds of an evergreen +plant, _Bixa Orellana_, which grows in the East and West Indian Islands +and South America, in the latter of which it is principally prepared. +Two kinds are imported, Spanish annatto, made in Brazil, and flag or +French, made mostly in Cayenne. These differ considerably in characters +and properties, the latter having a disagreeable putrescent odor, while +the Spanish is rather agreeable when fresh and good. It is, however, +inferior to the flag as a coloring or dyeing agent. The seeds from which +the substance is obtained are red on the outside, and two methods are +followed in order to obtain it. One is to rub or wash off the coloring +matter with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to bruise +the seeds, mix them with water, and allow fermentation to set in, during +which the coloring matter collects at the bottom, from which it is +subsequently removed and brought to the proper consistence by +spontaneous evaporation. These particulars, culled from Dr. Redwood's +remarks, may suffice to show its source and the methods for obtaining +it. + +Dr. John gives the following as the composition of the pulp surrounding +the seeds: Coloring resinous matter, 28; vegetable gluten, 26.5; +ligneous fiber, 20; coloring, 20; extractive matter, 4; and a trace of +spicy and acid matter. + +It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as well as +to preserve it, differs considerably from this; and though it may not be +true, as some hint, that manufacturing in this industry is simply a term +synonymous with adulterating, yet results will afterward be given +tending to show that there are articles in the market which have little +real claim to the title. I tried, but failed, to procure a sample of raw +material on which to work, with a view to learn something of its +characters and properties in this state, and thus be able to contrast it +with the manufactured or commercial article. The best thing to do in the +circumstances, I thought, was to operate on the highest priced sample at +disposal, and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the usual +way, I believe--was a more troublesome operation than it appeared to be, +as the following experiment will show: One hundred grains of No. 8 were +taken, dried thoroughly, reduced to fine powder, and introduced into a +flask containing 4 ounces of alcohol in the form of methylated spirit, +boiled for an hour--the flask during the operation being attached to an +inverted condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated with +diminishing quantities until in all 14 ounces had been used before the +alcoholic solution ceased to turn blue on the addition to it of strong +sulphuric acid, or failed to give a brownish precipitate with stannous +chloride. As the sample contained a considerable quantity of potassium +carbonate, in which the resin is soluble, it was thought that by +neutralizing this it might render the resin more easy of extraction. +This was found to be so, but it was accompanied by such a mass of +extractive as made it in the long run more troublesome, and hence it was +abandoned. Thinking the spirit employed might be too weak, an experiment +with commercial absolute alcohol was carried out as follows: One hundred +grains of a red sample, No. 4, were thoroughly dried, powdered finely, +and boiled in 2 ounces of the alcohol, filtered, and the residue treated +with half an ounce more. This required to be repeated with fresh half +ounces of the alcohol until in all 7½ were used; the time occupied from +first to last being almost three hours. This was considered +unsatisfactory, besides being very expensive, and so it, also, was set +aside, and a series of experiments with methylated spirit alone was set +in hand. The results showed that the easiest and most satisfactory way +was to take 100 grains (this amount being preferred, as it reduces error +to the minimum), dry thoroughly, powder finely, and macerate with +frequent agitation for twenty-four hours in a few ounces of spirit, then +to boil in this spirit for a short time, filter, and repeat the boiling +with a fresh ounce or so; this, as a rule, sufficing to completely +exhaust it of its resin. Wynter Blyth says that the red resin, or bixin, +is soluble in 25 parts of hot alcohol. It appears from these experiments +that much more is required to dissolve it out of commercial annatto. + +The full process followed consisted in determining the moisture by +drying 100 grains at 212° F. till constant, and taking this dried +portion for estimation of the resin in the way just stated. The +alcoholic extract was evaporated to dryness over a water-bath, the +residue dissolved in solution of sodium carbonate, and the resin +precipitated by dilute sulphuric acid (these reagents being chosen as +the best after numerous trials with others), added in the slightest +possible excess. The resin was collected on a tared double filter paper, +washed with distilled water until the washings were entirely colorless, +dried and weighed. + +The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of them. + +The results are as follows: + + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 + +The first six are the ordinary red rolls, with the exception of No. 4, +which is a red mass, the only one of this class direct from the +manufacturers. The remainder are brown cakes, all except No. 7 being +from the manufacturers direct. The ash of the first two was largely +common salt; that of No. 3 contained, besides this, iron in some +quantity. No. 4 is unique in many respects. It was of a bright red +color, and possessed a not disagreeable odor. It contained the largest +percentage of moisture and the lowest of ash; had, comparatively, a +large amount of coloring matter; was one of the cheapest, and in the +course of some dairy trials, carried out by an intelligent farmer, was +pronounced to be the best suited for coloring butter. So far as my +experience goes, it was a sample of the best commercial excellence, +though I fear the mass of water present and the absence of preserving +substances will assist in its speedy decay. Were such an article easily +procured in the usual way of business, there would not be much to +complain of, but it must not be forgotten that it was got direct from +the manufacturers--a somewhat suggestive fact when the composition of +some other samples is taken into account. No. 5 emitted a disagreeable +odor during ignition. The soluble portion of the ash was mostly common +salt, and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter gave +rise to disagreeable reflections. It was wrapped in a paper saturated +with a strongly smelling linseed oil. When it was boiled in water and +broken up, hairs, among other things, were observed floating about. It +contained some iron. The first cake, No. 7, gave off during ignition an +agreeable odor resembling some of the finer tobaccos, and this is +characteristic more or less of all the cakes. The ash weighed 52 per +cent., the soluble part of which, 18.5, was mostly potassium carbonate, +with some chlorides and sulphates; the insoluble, mostly chalk with iron +and alumina. No. 8--highest priced of all--had in the mass an odor which +I can compare to nothing else than a well rotted farmyard manure. Twenty +parts of the ash were soluble and largely potassium carbonate, the +insoluble being iron for the most part. The mineral portions of Nos. 9 +and 10 closely resemble No. 7. + +On looking over the results, it is found that the red rolls contained +starchy matters in abundance (in No. 4 the starch was to a large extent +replaced by water), and an ash, mostly sodium chloride, introduced no +doubt to assist in its preservation as well as to increase the color of +the resin--a well known action of salt on vegetable reds. The cakes, +which are mostly used for cheese coloring, I believe, all appeared to +contain turmeric, for they gave a more or less distinct reaction with +the boric acid test, and all except No. 8 contained large quantities of +chalk. These results in reference to extractive, etc., reveal nothing +that has not been known before. Wynter Blyth, who gives the only +analyses of annatto I have been able to find, states that the +composition of a fair commercial sample (which I take to mean the raw +article) examined by him was as follows: water, 24.2; resin, 28.8; ash, +22.5; and extractive, 24.5; and that of an adulterated (which I take to +mean a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. 27.3. If +this be correct, it appears that the articles at present in the market, +or at least those which have come in my way, have been wretched +imitations of the genuine thing, and should, instead of being called +adulterated annatto, be called something else adulterated, but not +seriously, with annatto. I have it on the authority of the farmer +previously referred to, that ¼ of an ounce of No. 4 is amply sufficient +to impart the desired cowslip tint to no less than 60 lb. of butter. +When so little is actually required, it does not seem of very serious +importance whether the adulterant or preservative be flour, chalk, or +water, but it is exasperating in a very high degree to have such +compounds as Nos. 3 and 6 palmed off as decent things when even Nos. 1, +2, and 5 have been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may be +induced to examine the annatto taken into stock more closely than I was +taught to do, and had been in the habit of doing, namely, to see if it +had a good consistence and an odor resembling black sugar, for if so, +the quality was above suspicion. + + * * * * * + + + + +JAPANESE RICE WINE AND SOJA SAUCE. + + +Professor P. Cohn has recently described the mode in which he has +manufactured the Japanese sake or rice wine in the laboratory. The +material used was "Tane Kosi," i.e., grains of rice coated with the +mycelium, conidiophores, and greenish yellow chains of conidia of +_Aspergillus Oryzoe_. The fermentation is caused by the mycelium of this +fungus before the development of the fructification. The rice is first +exposed to moist air so as to change the starch into paste, and then +mixed with grains of the "Tane Kosi." The whole mass of rice becomes in +a short time permeated by the soft white shining mycelium, which imparts +to it the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two or +three days, and then subjected to alcoholic fermentation from the +_Saccharomyces_, which is always present in the rice, but which has +nothing to do with the _Aspergillus_. The fermentation is completed in +two or three weeks, and the golden yellow, sherry-like sake is poured +off. The sample manufactured contained 13.9 per cent. of alcohol. +Chemical investigation showed that the _Aspergillus_ mycelium transforms +the starch into glucose, and thus plays the part of a diastase. + +Another substance produced from the _Aspergillus_ rice is the soja +sauce. The soja leaves, which contain little starch, but a great deal of +oil and casein, are boiled, mixed with roasted barley, and then with the +greenish yellow conidia powder of the _Aspergillus_. After the mycelium +has fructified, the mass is treated with a solution of sodium chloride, +which kills the _Aspergillus_, another fungus, of the nature of a +_Chalaza_, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce then +separates. + + * * * * * + + + + +ALUMINUM. + +[Footnote: Annual address delivered by President J.A. Price before the +meeting of the Scranton Board of Trade, Monday, January 18, 1886.] + +By J.A. PRICE. + + +Iron is the basis of our civilization. Its supremacy and power it is +impossible to overestimate; it enters every avenue of development, and +it may be set down as the prime factor in the world's progress. Its +utility and its universality are hand in hand, whether in the +magnificent iron steamship of the ocean, the network of iron rail upon +land, the electric gossamer of the air, or in the most insignificant +articles of building, of clothing, and of convenience. Without it, we +should have miserably failed to reach our present exalted station, and +the earth would scarcely maintain its present population; it is indeed +the substance of substances. It is the Archimedean lever by which the +great human world has been raised. Should it for a moment forget its +cunning and lose its power, earthquake shocks or the wreck of matter +could not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that it +must give way to a metal that has still greater proportions and vaster +possibilities. Strange and startling as may seem the assertion, yet I +believe it nevertheless to be true that we are approaching the period, +if not already standing upon the threshold of the day, when this magical +element will be radically supplanted, and when this valuable mineral +will be as completely superseded as the stone of the aborigines. With +all its apparent potency, it has its evident weaknesses; moisture is +everywhere at war with it, gases and temperature destroy its fiber and +its life, continued blows or motion crystallize and rob it of its +strength, and acids will devour it in a night. If it be possible to +eliminate all, or even one or more, of these qualities of weakness in +any metal, still preserving both quantity and quality, that metal will +be the metal of the future. + +The coming metal, then, to which our reference is made is aluminum, the +most abundant metal in the earth's crust. Of all substances, oxygen is +the most abundant, constituting about one-half; after oxygen comes +silicon, constituting about one-fourth, with aluminum third in all the +list of substances of the composition. Leaving out of consideration the +constituents of the earth's center, whether they be molten or gaseous, +more or less dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we find +that aluminum is beyond question the most abundant and the most useful +of all metallic substances. + +It is the metallic base of mica, feldspar, slate, and clay. Professor +Dana says: "Nearly all the rocks except limestones and many sandstones +are literally ore-beds of the metal aluminum." It appears in the gem, +assuming a blue in the sapphire, green in the emerald, yellow in the +topaz, red in the ruby, brown in the emery, and so on to the white, +gray, blue, and black of the slates and clays. It has been dubbed "clay +metal" and "silver made from clay;" also when mixed with any +considerable quantity of carbon becoming a grayish or bluish black "alum +slate." + +This metal in color is white and next in luster to silver. It has never +been found in a pure state, but is known to exist in combination with +nearly two hundred different minerals. Corundum and pure emery are ores +that are very rich in aluminum, containing about fifty-four per cent. +The specific gravity is but two and one-half times that of water; it is +lighter than glass or as light as chalk, being only one-third the weight +of iron and one-fourth the weight of silver; it is as malleable as gold, +tenacious as iron, and harder than steel, being next the diamond. Thus +it is capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. Its +variety of transformations is something wonderful. Meeting iron, or even +iron at its best in the form of steel, in the same field, it easily +vanquishes it at every point. It melts at 1,300 degrees F., or at least +600 degrees below the melting point of iron, and it neither oxidizes in +the atmosphere nor tarnishes in contact with gases. The enumeration of +the properties of aluminum is as enchanting as the scenes of a fairy +tale. + +Before proceeding further with this new wonder of science, which is +already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French chemist +Lavoisier, a very magician in the science, groping in the dark of the +last century, evolved the chemical theory of combustion--the existence +of a "highly respirable gas," oxygen, and the presence of metallic bases +in earths and alkalies. With the latter subject we have only to do at +the present moment. The metallic base was predicted, yet not identified. +The French Revolution swept this genius from the earth in 1794, and +darkness closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon the +metallic base of certain earths, but the reflection was so feeble that +the great secret was never revealed. Then a little later the Swedish +Berzelius and the Danish Oersted, confident in the prediction of +Lavoisier and of Davy, went in search of the mysterious stranger with +the aggressive electric current, but as yet to no purpose. It was +reserved to the distinguished German Wohler, in 1827, to complete the +work of the past fifty years of struggle and finally produce the minute +white globule of the pure metal from a mixture of the chloride of +aluminum and sodium, and at last the secret is revealed--the first step +was taken. It took twenty years of labor to revolve the mere discovery +into the production of the aluminum bead in 1846, and yet with this +first step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come. + +Returning again to France some time during the years between 1854 and +1858, and under the patronage of the Emperor Napoleon III., we behold +Deville at last forcing Nature to yield and give up this precious +quality as a manufactured product. Rose, of Berlin, and Gerhard, in +England, pressing hard upon the heels of the Frenchman, make permanent +the new product in the market at thirty-two dollars per pound. The +despair of three-quarters of a century of toilsome pursuit has been +broken, and the future of the metal has been established. + +The art of obtaining the metal since the period under consideration has +progressed steadily by one process after another, constantly increasing +in powers of productivity and reducing the cost. These arts are +intensely interesting to the student, but must be denied more than a +reference at this time. The price of the metal may be said to have come +within the reach of the manufacturing arts already. + +A present glance at the uses and possibilities of this wonderful metal, +its application and its varying quality, may not be out of place. Its +alloys are very numerous and always satisfactory; with iron, producing a +comparative rust proof; with copper, the beautiful golden bronze, and so +on, embracing the entire list of articles of usefulness as well as works +of art, jewelry, and scientific instruments. + +Its capacity to resist oxidation or rust fits it most eminently for all +household and cooking utensils, while its color transforms the dark +visaged, disagreeable array of pots, pans, and kitchen implements into +things of comparative beauty. As a metal it surpasses copper, brass, and +tin in being tasteless and odorless, besides being stronger than either. + +It has, as we have seen, bulk without weight, and consequently may be +available in construction of furniture and house fittings, as well in +the multitudinous requirements of architecture. The building art will +experience a rapid and radical change when this material enters as a +component material, for there will be possibilities such as are now +undreamed of in the erection of homes, public buildings, memorial +structures, etc. etc., for in this metal we have the strength, +durability, and the color to give all the variety that genius may +dictate. + +And when we take a still further survey of the vast field that is +opening before us, we find in the strength without size a most desirable +assistant in all the avenues of locomotion. It is the ideal metal for +railway traffic, for carriages and wagons. The steamships of the ocean +of equal size will double their cargo and increase the speed of the +present greyhounds of the sea, making six days from shore to shore seem +indeed an old time calculation and accomplishment. A thinner as well as +a lighter plate; a smaller as well as a stronger engine; a larger as +well as a less hazardous propeller; and a natural condition of +resistance to the action of the elements; will make travel by water a +forcible rival to the speed attained upon land, and bring all the +distant countries in contact with our civilization, to the profit of +all. This metal is destined to annihilate space even beyond the dream of +philosopher or poet. + +The tensile strength of this material is something equally wonderful, +when wire drawn reaches as high as 128,000 pounds, and under other +conditions reaches nearly if not quite 100,000 pounds to the square +inch. The requirements of the British and German governments in the best +wrought steel guns reach only a standard of 70,000 pounds to the square +inch. Bridges may be constructed that shall be lighter than wooden ones +and of greater strength than wrought steel and entirely free from +corrosion. The time is not distant when the modern wonder of the +Brooklyn span will seem a toy. + +It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube. + +The resistance to corrosion evidently fits this metal for railway +sleepers to take the place of the decaying wooden ties. In this metal +the sleeper may be made as soft and yielding as lead, while the rail may +be harder and tougher than steel, thus at once forming the necessary +cushion and the avoidance of jar and noise, at the same time +contributing to additional security in virtue of a stronger rail. + +In conductivity this metal is only exceeded by copper, having many times +that of iron. Thus in telegraphy there are renewed prospects in the +supplanting of the galvanized iron wire--lightness, strength, and +durability. When applied to the generation of steam, this material will +enable us to carry higher pressure at a reduced cost and increased +safety, as this will be accomplished by the thinner plate, the greater +conductivity of heat, and the better fiber. + +It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in the +mechanic art lies dormant--the size of the machine may be reduced, the +speed and the power increased, realizing the conception of two things +better done than one before. It is one of man's creative acts. + +From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, Paris, +asserts that 120,000 blows will exhaust the usefulness of the cushion of +the stamp machine, and this number of blows is given in a day; and that +when a cushion of aluminum bronze was substituted, it was unaffected +after months of use. + +If we have found a metal that possesses both tensile strength and +resistance to compression; malleability and ductility--the quality of +hardening, softening, and toughening by tempering; adaptability to +casting, rolling, or forging; susceptibility to luster and finish; of +complete homogeneous character and unusually resistant to destructive +agents--mankind will certainly leave the present accomplishments as +belonging to an effete past, and, as it were, start anew in a career of +greater prospects. + +This important material is to be found largely in nearly all the rocks, +or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal." +It is in every clay bank. It is particularly abundant in the coal +measures and is incidental to the shales or slates and clays that +underlie the coal. This under clay of the coal stratum was in all +probability the soil out of which grew the vegetation of the coal +deposits. It is a compound of aluminum and other matter, and, when mixed +with carbon and transformed by the processes of geologic action, it +becomes the shale rock which we know and which we discard as worthless +slate. And it is barely possible that we have been and are still carting +to the refuse pile an article more valuable than the so greatly lauded +coal waste or the merchantable coal itself. We have seen that the best +alumina ore contains only fifty-four per cent. of metal. + +The following prepared table has been furnished by the courtesy and +kindness of Mr. Alex. H. Sherred, of Scranton. + + ALUMINA. + +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 + +It will be seen that the black clay, shale, or slate, has a constituent +of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the +highest. Under every stratum of coal, and frequently mixed with it, are +these under deposits that are rich in the metal. When exposed to the +atmosphere, these shales yield a small deposit of alum. In the +manufacture of alum near Glasgow the shale and slate clay from the old +coal pits constitute the material used, and in France alum is +manufactured directly from the clay. + +Sufficient has been advanced to warrant the additional assertion that we +are here everywhere surrounded by this incomparable mineral, that it is +brought to the surface from its deposits deep in the earth by the +natural process in mining, and is only exceeded in quantity by the coal +itself. Taking a columnar section of our coal field, and computing the +thickness of each shale stratum, we have from twenty-five to sixty feet +in thickness of this metal-bearing substance, which averages over +twenty-five per cent. of the whole in quantity in metal. + +It is readily apparent that the only task now before us is the reduction +of the ore and the extraction of the metal. Can this be done? We answer, +it has been done. The egg has stood on end--the new world has been +sighted. All that now remains is to repeat the operation and extend the +process. Cheap aluminum will revolutionize industry, travel, comfort, +and indulgence, transforming the present into an even greater +civilization. Let us see. + +We have seen the discovery of the mere chemical existence of the metal, +we have stood by the birth of the first white globule or bead by Wohler, +in 1846, and witnesssed its introduction as a manufactured product in +1855, since which time, by the alteration and cheapening of one process +after another, it has fallen in price from thirty-two dollars per pound +in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent +labor at smelting have increased the quantity over a thousandfold and +reduced the cost upward of fifty per cent. + +All these processes involve the application of heat--a mere question of +the appliances. The electric currents of Berzelius and Oersted, the +crucible of Wohler, the closed furnaces and the hydrogen gas of the +French manufacturers and the Bessemer converter apparatus of Thompson, +all indicate one direction. This metal can be made to abandon its bed in +the earth and the rock at the will of man. During the past year, the +Messrs. Cowles, of Cleveland, by their electric smelting process, claim +to have made it possible to reduce the price of the metal to below four +dollars per pound; and there is now erecting at Lockport, New York, a +plant involving one million of capital for the purpose. + +Turning from the employment of the expensive reducing agents to the +simple and sole application of heat, we are unwilling to believe that we +do not here possess in eminence both the mineral and the medium of its +reduction. Whether the electric or the reverberatory or the converter +furnace system be employed, it is surely possible to produce the result. + +To enter into consideration of the details of these constructions would +involve more time than is permitted us on this occasion. They are very +interesting. We come again naturally to the limitless consideration of +powdered fuel, concerning which certain conclusions have been reached. +In the dissociation of water into its hydrogen and oxygen, with the +mingled carbon in a powdered state, we undoubtedly possess the elements +of combustion that are unexcelled on earth, a heat-producing combination +that in both activity and power leaves little to be desired this side of +the production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and furnaces. + +In the hope of stimulating thought to this infinite question of proper +fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope this +Board will not grudgingly devote to the subject, but which is impossible +at present. Do not forget that there is no single spot on the face of +the globe where nature has lavished more freely her choicest gifts. Let +us be active in the pursuit of the treasure and grateful for the +distinguished consideration. + + * * * * * + + + + +THE ORIGIN OF METEORITES. + + +On January 9, Professor Dewar delivered the sixth and last of his series +of lectures at the Royal Institution on "The Story of a Meteorite." [For +the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that +cosmic dust is found on Arctic snows and upon the bottom of the ocean; +all over the world, in fact, at some time or other, there has been a +large deposit of this meteoric dust, containing little round nodules +found also in meteorites. In Greenland some time ago numbers of what +were supposed to be meteoric stones were found; they contained iron, and +this iron, on being analyzed at Copenhagen, was found to be rich in +nickel. The Esquimaux once made knives from iron containing nickel; and +as any such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited the +basaltic coast in Greenland from which some of the supposed meteoric +stones had been brought, and in the middle of the rock large nodules +were found composed of iron and nickel; it, therefore, became evident +that the earth might produce masses not unlike such as come to us as +meteorites. The lecturer here exhibited a section of the Greenland rock +containing the iron, and nickel alloy, mixed with stony crystals, and +its resemblance to a section of a meteorite was obvious. It was 2½ times +denser than water, yet the whole earth is 5½ times denser than water, so +that if we could go deep enough, it is not improbable that our own globe +might be found to contain something like meteoric iron. He then called +attention to the following tables: + + _Elementary Substances found in Meteorites_. + + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. + +_Density of Meteorites_. + + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 + +_Interior of the Earth_ + + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 + +[Illustration] + +Twice a year, said Professor Dewar, what are called "falling stars" +maybe plentifully seen; the times of their appearance are in August and +November. Although thousands upon thousands of such small meteors have +passed through our atmosphere, there is no distinct record of one having +ever fallen to the earth during these annual displays. One was said to +have fallen recently at Naples, but on investigation it turned out to be +a myth. These annual meteors in the upper air are supposed to be only +small ones, and to be dissipated into dust and vapor at the time of +their sudden heating; so numerous are they that 40,000 have been counted +in one evening, and an exceptionally great display comes about once in +33¼ years. The inference from their periodicity is, that they are small +bodies moving round the sun in orbits of their own, and that whenever +the earth crosses their orbits, thereby getting into their path, a +splendid display of meteors results. A second display, a year later, +usually follows the exceptionally great display just mentioned, +consequently the train of meteors is of great length. Some of these +meteors just enter the atmosphere of the earth, then pass out again +forever, with their direction of motion altered by the influence of the +attraction of the earth. He here called attention to the accompanying +diagram of the orbits of meteors. + +The lecturer next invited attention to a hollow globe of linen or some +light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and +contained hidden within it the great electro-magnet, weighing 2 cwt., so +often used by Faraday in his experiments. He also exhibited a ball made +partly of thin iron; the globe represented the earth, for the purposes +of the experiment, and the ball a meteorite of somewhat large relative +size. The ball was then discharged at the globe from a little catapult; +sometimes the globe attracted the ball to its surface, and held it +there, sometimes it missed it, but altered its curve of motion through +the air. So was it, said the lecturer, with meteorites when they neared +the earth. Photographs from drawings, by Professor A. Herschel, of the +paths of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, is a +proof that their motions are parallel to each other; the parallel lines +seem to draw to a point at the greatest distance, for the same reason +that the rails of a straight line of railway seem to come from a distant +central point. The most interesting thing about the path of a company of +meteors is, that a comet is known to move in the same orbit; the comet +heads the procession, the meteors follow, and they are therefore, in all +probability, parts of comets, although everything about these difficult +matters cannot as yet be entirely explained; enough, however, is known +to give foundation for the assumption that meteorites and comets are not +very dissimilar. + +The light of a meteorite is not seen until it enters the atmosphere of +the earth, but falling meteorites can be vaporized by electricity, and +the light emitted by their constituents be then examined with the +spectroscope. The light of comets can be directly examined, and it +reveals the presence in those bodies of sodium, carbon, and a few other +well-known substances. He would put a piece of meteorite in the electric +arc to see what light it would give; he had never tried the experiment +before. The lights of the theater were then turned down, and the +discourse was continued in darkness; among the most prominent lines +visible in the spectrum of the meteorite, Professor Dewar specified +magnesium, sodium, and lithium. "Where do meteorites come from?" said +the lecturer. It might be, he continued, that they were portions of +exploded planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular hypothesis +that at some long past time our sun and all his planets existed but as a +volume of gas, which in contracting and cooling formed a hot volume of +rotating liquid, and that as this further contracted and cooled, the +planets, and moons, and planetary rings fell off from it and gradually +solidified, the sun being left as the solitary comparatively uncooled +portion of the original nebula. In partial illustration of this, he +caused a little globe of oil, suspended in an aqueous liquid of nearly +its own specific gravity, to rotate, and as it rotated it was seen, by +means of its magnified image upon the screen, to throw off from its +outer circumference rings and little globes. + + * * * * * + + + + +CANDELABRA CACTUS AND CALIFORNIA WOODPECKER. + +By C.F. HOLDER. + + +One of the most picturesque objects that meet the eye of the traveler +over the great plains of the southern portion of California and New +Mexico is the candelabra cactus. Systematically it belongs to the Cereus +family, in which the notable Night-blooming Cereus also is naturally +included. In tropical or semi-tropical countries these plants thrive, +and grow to enormous size. For example, the Cereus that bears those +great flowers, and blooms at night, exhaling powerful perfume, as we see +them in hothouses in our cold climate, are even in the semi-tropical +region of Key West, on the Florida Reef, seen to grow enormously in +length. + +[Illustration: THE CANDELABRA CACTUS--CEREUS GIGANTEUS.] + +We cultivated several species of the more interesting forms during a +residence on the reef. Our brick house, two stories in height, was +entirely covered on a broad gable end, the branches more than gaining +the top. There is a regular monthly growth, and this is indicated by a +joint between each two lengths. Should the stalk be allowed to grow +without support, it will continue growing without division, and exhibit +stalks five or six feet in length, when they droop, and fall upon the +ground. + +Where there is a convenient resting place on which it can spread out and +attach itself, the stalk throws out feelers and rootlets, which fasten +securely to the wall or brickwork; then, this being a normal growth, +there is a separation at intervals of about a foot. That is, the stalk +grows in one month about twelve inches, and if it has support, the +middle woody stalk continues to grow about an inch further, but has no +green, succulent portion, in fact, looks like a stem; then the other +monthly growth takes place, and ends with a stem, and so on +indefinitely. Our house was entirely covered by the stems of such a +plant, and the flowers were gorgeous in the extreme. The perfume, +however, was so potent that it became a nuisance. Such is the +Night-blooming Cereus in the warm climates, and similarly the Candelabra +Cereus grows in stalks, but architecturally erect, fluted like columns. +The flowers are large, and resemble those of the night-blooming variety. +Some columns remain single, and are amazingly artificial appearing; +others throw off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being clusters +of side shoots, the latter putting out from the trunk regularly, and +standing up parallel to each other. The enormous size these attain is +well shown in the picture. + +Whenever the great stalks of these cacti die, the succulent portion is +dried, and nothing is left but the woody fiber. They are hollow in +places, and easily penetrated. A species of woodpecker, _Melanerpes +formicivorus_, is found to have adopted the use of these dry stalks for +storing the winter's stock of provisions. There are several round +apertures seen on the stems in the pictures, which were pecked by this +bird. This species of woodpecker is about the size of our common robin +or migratory thrush, and has a bill stout and sharp. The holes are +pecked for the purpose of storing away acorns or other nuts; they are +just large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts are +so numerous, the stalk has the appearance of being studded with bullets. +This appearance is more pronounced in cases where the dead trunk of an +oak is used. There are some specimens of the latter now owned by the +American Museum of Natural History, which were originally sent to the +Centennial Exhibition at Philadelphia. They were placed in the +department contributed by the Pacific Railroad Company, and at that time +were regarded as some of the wonders of that newly explored region +through which the railroad was then penetrating. Some portions of the +surface of these logs are nearly entirely occupied by the holes with +acorns in them. The acorns are driven in very tightly in these examples; +much more so than in the cactus plants, as the oak is nearly round, and +the holes were pecked in solid though dead wood. One of the most +remarkable circumstances connected with this habit of the woodpecker is +the length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to make a +journey of sixty miles to accomplish the storing of one acorn. At first +it seemed strange that a bird should spend so much labor to place those +bits of food, and so far away. De Saussure, a Swiss naturalist, +published in the _Bibliotheque Universelle_, of Geneva, entertaining +accounts of the Mexican Colaptes, a variety of the familiar "high hold," +or golden winged woodpecker. They were seen to store acorns in the dead +stalks of the maguey (_Agave Americana_). Sumichrast, who accompanied +him to Central America, records the same facts. These travelers saw +great numbers of the woodpeckers in a region on the slope of a range of +volcanic mountains. There was little else of vegetation than the +_Agave_, whose barren, dead stems were studded with acorns placed there +by the woodpeckers. + +The maguey throws up a stalk about fifteen feet in height yearly, which, +after flowering, grows stalky and brittle, and remains an unsightly +thing. The interior is pithy, but after the death of the stalk the pith +contracts, and leaves the greater portion of the interior hollow, as we +have seen in the case of the cactus branches. How the birds found that +these stalks were hollow is a problem not yet solved, but, nevertheless, +they take the trouble to peck away at the hard bark, and once +penetrated, they commence to fill the interior; when one space is full, +the bird pecks a little higher up, and so continues. + +Dr. Heerman, of California, describes the California _Melanerpes_ as one +of the most abundant of the woodpeckers; and remarks that it catches +insects on the wing like a flycatcher. It is well determined that it +also eats the acorns that it takes so much pains to transport. + +[Illustration: FLOWER OF CEREUS GIGANTEUS.] + +It seems that these birds also store the pine trees, as well as the +oaks. It is not quite apparent why these birds exhibit such variation in +habits; they at times select the more solid trees, where the storing +cannot go on without each nut is separately set in a hole of its own. +There seems an instinct prompting them to do this work, though there may +not be any of the nuts touched again by the birds. Curiously enough, +there are many instances of the birds placing pebbles instead of nuts in +holes they have purposely pecked for them. Serious trouble has been +experienced by these pebbles suddenly coming in contact with the saw of +the mill through which the tree is running. The stone having been placed +in a living tree, as is often the case, its exterior had been lost to +sight during growth. + +Some doubt has been entertained about the purpose of the bird in storing +the nuts in this manner. De Saussure tells us he has witnessed the birds +eating the acorns after they had been placed in holes in trees, and +expresses his conviction that the insignificant grub which is only seen +in a small proportion of nuts is not the food they are in search of. + +C.W. Plass, Esq., of Napa City, California, had an interesting example +of the habits of the California _Melanerpes_ displayed in his own house. +The birds had deposited numbers of acorns in the gable end. A +considerable number of shells were found dropped underneath the eaves, +while some were found in place under the gable, and these were perfect, +having no grubs in them. + +The picture shows a very common scene in New Mexico. The columns, +straight and angular, are often sixty feet in height. It is called torch +cactus in some places. There are many varieties, and as many different +shapes. Some lie on the ground; others, attached to trunks of trees as +parasites, hang from branches like great serpents; but none is so +majestic as the species called systematically _Cereus giganteus_, most +appropriately. The species growing pretty abundantly on the island of +Key West is called candle cactus. It reaches some ten or twelve feet, +and is about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a pretty, +rather picturesque feature in the otherwise barren undergrowth of +shrubbery and small trees. Accompanied by a few flowering cocoa palms, +the view is not unpleasing. The fiber of these plants is utilized in +some coarse manufactures. The maguey, or Agave, is used in the +manufacture of fine roping. Manila hemp is made from a species. The +species whose dried stalks are used by the woodpeckers for their winter +storage was cultivated at Key West, Florida, during several years before +1858. Extensive fields of the Agave stood unappropriated at that period. +Considerable funds were dissipated on this venture. Extensive works were +established, and much confidence was entertained that the scheme would +prove a paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their long +stalks, stand now, increasing every year, until a portion of the island +is overrun with them. + + +CEREUS GIGANTEUS. + +This wonderful cactus, its colossal proportions, and weird, yet grand, +appearance in the rocky regions of Mexico and California, where it is +found in abundance, have been made known to us only through books of +travel, no large plants of it having as yet appeared in cultivation in +this country. It is questionable if ever the natural desire to see such +a vegetable curiosity represented by a large specimen in gardens like +Kew can be realized, owing to the difficulty of importing large stems in +a living condition; and even if successfully brought here, they survive +only a very short time. To grow young plants to a large size seems +equally beyond our power, as plants 6 inches high and carefully managed +are quite ten years old. When young, the stem is globose, afterward +becoming club-shaped or cylindrical. It flowers at the height of 12 +feet, but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of an +immense candelabrum, the base of the stem being as thick as a man's +body. The flower, of which a figure is given here, is about 5 inches +long and wide, the petals cream colored, the sepals greenish white. +Large clusters of flowers are developed together near the top of the +stem. A richly colored edible fruit like a large fig succeeds each +flower, and this is gathered by the natives and used as food under the +name of saguarro. A specimen of this cactus 3 feet high may be seen in +the succulent house at Kew.--_B., The Garden_. + + * * * * * + + + + +HOW PLANTS ARE REPRODUCED. + +[Footnote: Read at a meeting of the Chemists' Assistants' Association. +December 16, 1885.] + +By C.E. STUART, B.Sc. + + +In two previous papers read before this Association I have tried to +condense into as small a space as I could the processes of the nutrition +and of the growth of plants; in the present paper I want to set before +you the broad lines of the methods by which plants are reproduced. + +Although in the great trees of the conifers and the dicotyledons we have +apparently provision for growth for any number of years, or even +centuries, yet accident or decay, or one of the many ills that plants +are heirs to, will sooner or later put an end to the life of every +individual plant. + +Hence the most important act of a plant--not for itself perhaps, but for +its race--is the act by which it, as we say, "reproduces itself," that +is, the act which results in the giving of life to a second individual +of the same form, structure, and nature as the original plant. + +The methods by which it is secured that the second generation of the +plant shall be as well or even better fitted for the struggle of life +than the parent generation are so numerous and complicated that I cannot +in this paper do more than allude to them; they are most completely seen +in cross fertilization, and the adaptation of plant structures to that +end. + +What I want to point out at present are the principles and not so much +the details of reproduction, and I wish you to notice, as I proceed, +what is true not only of reproduction in plants but also of all +processes in nature, namely, the paucity of typical methods of attaining +the given end, and the multiplicity of special variation from those +typical methods. When we see the wonderfully varied forms of plant life, +and yet learn that, so to speak, each edifice is built with the same +kind of brick, called a cell, modified in form and function; when we see +the smallest and simplest equally with the largest and most complicated +plant increasing in size subject to the laws of growth by +intussusception and cell division, which are universal in the organic +world; we should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types. + +The first great generalization is into-- + +1. The vegetative type of reproduction, in which one or more ordinary +cells separate from the parent plant and become an independent plant; +and-- + +2. The special-cell type of reproduction, in which either one special +cell reproduces the plant, or two special cells by their union form the +origin of the new plant; these two modifications of the process are +known respectively as asexual and sexual. + +The third modification is a combination of the two others, namely, the +asexual special cell does not directly reproduce its parent form, but +gives rise to a structure in which sexual special cells are developed, +from whose coalescence springs again the likeness of the original plant. +This is termed alternation of generations. + +The sexual special cell is termed the _spore_. + +The sexual special cells are of one kind or of two kinds. + +Those which are of one kind may be termed, from their habit of yoking +themselves together, _zygoblasts_, or conjugating cells. + +Those which are of two kinds are, first, a generally aggressive and +motile fertilizing or so-called "male cell," called in its typical form +an _antherozoid_; and, second, a passive and motionless receptive or +so-called "female cell," called an _oosphere_. + +The product of the union of two zygoblasts is termed a _zygospore_. + +The product of the union of an antherozoid and an oosphere is termed an +_oospore_. + +In many cases the differentiation of the sexual cells does not proceed +so far as the formation of antherozoids or of distinct oospheres; these +cases I shall investigate with the others in detail presently. + +First, then, I will point out some of the modes of vegetative +reproduction. + +The commonest of these is cell division, as seen in unicellular plants, +such as protococcus, where the one cell which composes the plant simply +divides into two, and each newly formed cell is then a complete plant. + +The particular kind of cell division termed "budding" here deserves +mention. It is well seen in the yeast-plant, where the cell bulges at +one side, and this bulge becomes larger until it is nipped off from the +parent by contraction at the point of junction, and is then an +independent plant. + +Next, there is the process by which one plant becomes two by the dying +off of some connecting portion between two growing parts. + +Take, for instance, the case of the liverworts. In these there is a +thallus which starts from a central point and continually divides in a +forked or dichotomous manner. Now, if the central portion dies away, it +is obvious that there will be as many plants as there were forkings, and +the further the dying of the old end proceeds, the more young plants +will there be. + +Take again, among higher plants, the cases of suckers, runners, stolons, +offsets, etc. Here, by a process of growth but little removed from the +normal, portions of stems develop adventitious roots, and by the dying +away of the connecting links may become independent plants. + +Still another vegetative method of reproduction is that by bulbils or +gemmæ. + +A bulbil is a bud which becomes an independent plant before it commences +to elongate; it is generally fleshy, somewhat after the manner of a +bulb, hence its name. Examples occur in the axillary buds of _Lilium +bulbiferum_, in some _Alliums_, etc. + +The gemma is found most frequently in the liverworts and mosses, and is +highly characteristic of these plants, in which indeed vegetative +reproduction maybe said to reach its fullest and most varied extent. + +Gemmæ are here formed in a sort of flat cup, by division of superficial +cells of the thallus or of the stem, and they consist when mature of +flattened masses of cells, which lie loose in the cup, so that wind or +wet will carry them away on to soil or rock, when, either by direct +growth from apical cells, as with those of the liverworts, or with +previous emission of thread-like cells forming a "protonema," in the +case of the mosses, the young plant is produced from them. + +The lichens have a very peculiar method of gemmation. The lichen-thallus +is composed of chains or groups of round chlorophyl-containing cells, +called "gonidia," and masses of interwoven rows of elongated cells which +constitute the hyphæ. Under certain conditions single cells of the +gonidia become surrounded with a dense felt of hyphæ, these accumulate +in numbers below the surface of the thallus, until at last they break +out, are blown or washed away, and start germination by ordinary cell +division, and thus at once reproduce a fresh lichen-thallus. These +masses of cells are called soredia. + +Artificial budding and grafting do not enter into the scope of this +paper. + +As in the general growth and the vegetative reproduction of plants +cell-division is the chief method of cell formation, so in the +reproduction of plants by special cells the great feature is the part +played by cells which are produced not by the ordinary method of cell +division, but by one or the other processes of cell formation, namely, +free-cell formation or rejuvenescence. + +If we broaden somewhat the definition of rejuvenescence and free-cell +formation, and do not call the mother-cells of spores of mosses, higher +cryptogams, and also the mother-cells of pollen-grains, reproductive +cells, which strictly speaking they are not, but only producers of the +spores or pollen-grains, then we may say that _cell-division is confined +to vegetative processes, rejuvenescence and free-cell formation are +confined to reproductive processes_. + +Rejuvenescence may be defined as the rearrangement of the whole of the +protoplasm of a cell into a new cell, which becomes free from the +mother-cell, and may or may not secrete a cell-wall around it. + +If instead of the whole protoplasm of the cell arranging itself into one +mass, it divides into several, or if portions only of the protoplasm +become marked out into new cells, in each case accompanied by rounding +off and contraction, the new cells remaining free from one another, and +usually each secreting a cell wall, then this process, whose relation to +rejuvenescence is apparent, is called free-cell formation. + +The only case of purely vegetative cell-formation which takes place by +either of these processes is that of the formation of endosperm in +Selaginella and phanerogams, which is a process of free-cell formation. + +On the other hand, the universal contraction and rounding off of the +protoplasm, and the formation by either rejuvenescence or free-cell +formation, distinctly mark out the special or true reproductive cell. + +Examples of reproductive cells formed by rejuvenescence are: + +1. The swarm spores of many algæ, as Stigeoclonium (figured in Sachs' +"Botany"). Here the contents of the cell contract, rearrange themselves, +and burst the side of the containing wall, becoming free as a +reproductive cell. + +2. The zygoblasts of conjugating algæ, as in Spirogyra. Here the +contents of a cell contract and rearrange themselves only after contact +of the cell with one of another filament of the plant. This zygoblast +only becomes free after the process of conjugation, as described below. + +3. The oosphere of characeæ, mosses and liverworts, and vascular +cryptogams, where in special structures produced by cell-divisions there +arise single primordial cells, which divide into two portions, of which +the upper portion dissolves or becomes mucilaginous, while the lower +contracts and rearranges itself to form the oosphere. + +4. Spores of mosses and liverworts, of vascular cryptogams, and pollen +cells of phanerogams, which are the analogue of the spores. + +The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes a +wall of its own, and by the bursting or absorption of the wall of its +mother-cell becomes free. This is evidently a rejuvenescence. + +Examples of reproductive cells formed by free-cell formation are: + +1. The ascospores of fungi and algæ. + +2. The zoospores or mobile spores of many algæ and fungi. + +3. The germinal vesicles of phanerogams. + +The next portion of my subject is the study of the methods by which +these special cells reproduce the plant. + +1st. Asexual methods. + +1. Rejuvenescence gives rise to a swarm-spore or zoospore. The whole of +the protoplasm of a cell contracts, becomes rounded and rearranged, and +escapes into the water, in which the plant floats as a mass of +protoplasm, clear at one end and provided with cilia by which it is +enabled to move, until after a time it comes to rest, and after +secreting a wall forms a new plant by ordinary cell-division. Example: +Oedogonium. + +2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya. + +3. Free-cell formation forms the typical motionless spore of algæ and +fungi. For instance, in the asci of lichens there are formed from a +portion of the protoplasm four or more small ascospores, which secrete a +cell-wall and lie loose in the ascus. Occasionally these spores may +consist of two or more cells. They are set free by the rupture of the +ascus, and germinate by putting out through their walls one or more +filaments which branch and form the thallus of a new individual. Various +other spores formed in the same way are known as _tetraspores_, etc. + +4. Cell-division with rejuvenescence forms the spores of mosses and +higher cryptogams. + +To take the example of moss spores: + +Certain cells in the sporogonium of a moss are called mother-cells. The +protoplasm of each one of these becomes divided into four parts. Each of +these parts then secretes a cell-wall and becomes free as a spore by the +rupture or absorption of the wall of the mother-cell. The germination of +the spores I shall describe later. + +5. A process of budding which in the yeast plant and in mosses is merely +vegetatively reproductive, in fungi becomes truly reproductive, namely, +the buds are special cells arising from other special cells of the +hyphæ. + +For example, the so-called "gills" of the common mushroom have their +surface composed of the ends of the threads of cells constituting the +hyphæ. Some of these terminal cells push out a little finger of +protoplasm, which swells, thickens its wall, and becomes detached from +the mother-cell as a spore, here called specially a _basidiospore_. + +Also in the common gray mould of infusions and preserves, Penicillium, +by a process which is perhaps intermediate between budding and +cell-division, a cell at the end of a hypha constricts itself in several +places, and the constricted portions become separate as _conidiospores_. + +_Teleutospores, uredospores_, etc., are other names for spores similarly +formed. + +These conidiospores sometimes at once develop hyphæ, and sometimes, as +in the case of the potato fungus, they turn out their contents as a +swarm-spore, which actively moves about and penetrates the potato leaves +through the stomata before they come to rest and elongate into the +hyphal form. + +So far for asexual methods of reproduction. + +I shall now consider the sexual methods. + +The distinctive character of these methods is that the cell from which +the new individual is derived is incapable of producing by division or +otherwise that new individual without the aid of the protoplasm of +another cell. + +Why this should be we do not know; all that we can do is to guess that +there is some physical or chemical want which is only supplied through +the union of the two protoplasmic masses. The process is of benefit to +the species to which the individuals belong, since it gives it a greater +vigor and adaptability to varying conditions, for the separate +peculiarities of two individuals due to climatic or other conditions are +in the new generation combined in one individual. + +The simplest of the sexual processes is conjugation. Here the two +combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union. + +Conjugation occurs in algæ and fungi. A typical case is that of +Spirogyra. This is an alga with its cells in long filaments. Two +contiguous cells of two parallel filaments push each a little projection +from its cell-wall toward the other. When these meet, the protoplasm of +each of the two cells contracts, and assumes an elliptical form--it +undergoes rejuvenescence. Next an opening forms where the two cells are +in contact, and the contents of one cell pass over into the other, where +the two protoplasmic bodies coalesce, contract, and develop a cell-wall. +The zygospore thus formed germinates after a long period and forms a new +filament of cells. + +Another example of conjugation is that of Pandorina, an alga allied to +the well-known volvox. Here the conjugating cells swim free in water; +they have no cell-wall, and move actively by cilia. Two out of a number +approach, coalesce, contract, and secrete a cell-wall. After a long +period of rest, this zygospore allows the whole of its contents to +escape as a swarm-spore, which after a time secretes a gelatinous wall, +and by division reproduces the sixteen-celled family. + +We now come to fertilization, where the uniting cells are of two kinds. + +The simplest case is that of Vaucheria, an alga. Here the vegetative +filament puts out two protuberances, which become shut off from the body +of the filament by partitions. The protoplasm in one of these +protuberances arranges itself into a round mass--the oosphere or female +cell. The protoplasm of the other protuberance divides into many small +masses, furnished with cilia, the spermatozoids or male cells. Each +protuberance bursts, and some of the spermatozoids come in contact with +and are absorbed by the oosphere, which then secretes a cell-wall, and +after a time germinates. + +The most advanced type of fertilization is that of angiosperms. + +In them there are these differences from the above process: the contents +of the male cell, represented by the pollen, are not differentiated into +spermatozoids, and there is no actual contact between the contents of +the pollen tube and the germinal vesicle, but according to Strashurger, +there is a transference of the substance of the nucleus of the pollen +cell to that of the germinal vesicle by osmose. The coalescence of the +two nuclei within the substance of the germinal vesicle causes the +latter to secrete a wall, and to form a new plant by division, being +nourished the while by the mother plant, from whose tissues the young +embryo plant contained in the seed only becomes free when it is in an +advanced stage of differentiation. + +Perhaps the most remarkable cases of fertilization occur in the Florideæ +or red seaweeds, to which class the well-known Irish moss belongs. + +Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, some +other cell which is quite distinct from the primarily fertilized cell +carries on the reproductive process. + +If the allied group of the Coleochæteæ is considered together with the +Florideæ, we find a transition between the ordinary case of Coleochæte +and that of Dudresnaya. In Coleochæte, the male cell is a round +spermatozoid, and the female cell an oosphere contained in the base of a +cell which is elongated into an open and hair-like tube called the +trichogyne. The spermatozoid coalesces with the oosphere, which secretes +a wall, becomes surrounded with a covering of cells called a cystocarp, +which springs from cells below the trichogyne, and after the whole +structure falls from the parent plant, spores are developed from the +oospore, and from them arises a new generation. + +In Dudresnaya, on the other hand, the spermatozoid coalesces indeed with +the trichogyne, but this does not develop further. From below the +trichogyne, however, spring several branches, which run to the ends of +adjacent branches, with the apical cells of which they conjugate, and +the result of this conjugation is the development of a cystocarp similar +to that of Coleochæte. The remarkable point here is the way in which the +effect of the fertilizing process is carried from one cell to another +entirely distinct from it. + +Thus I have endeavored to sum up the processes of asexual and of sexual +reproduction. But it is a peculiar characteristic of most classes of +plants that the cycle of their existence is not complete until both +methods of reproduction have been called into play, and that the +structure produced by one method is entirely different from that +produced by the other method. + +Indeed, it is only in some algæ and fungi that the reproductive cells of +one generation produce a generation similar to the parent; in all other +plants a generation A produces are unlike generation B, which may either +go on to produce another generation, C, and then back to A, or it may go +on producing B's until one of these reproduces A, or again it may +directly reproduce; A. Thus we have the three types: + + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. + +The first case is not common, the usual number of generations being two +only; but a typical example of the occurrence of three generations is in +such fungi as _Puccinia Graminis_. Here the first generation grows on +barberry leaves, and produces a kind of spore called an _æcidium spore_. +These æcidium spores germinate only on a grass stem or leaf, and a +distinct generation is produced, having a particular kind of spore +called an _uredospore_. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation with +another kind of spore, called a _teleutospore_, is produced. + +The teleutospores only germinate on barberry leaves, and there reproduce +the original æcidium generation. + +Thus we have the series A.B.B.B ... BCA + +In this instance all the generations are asexual, but the most common +case is for the sexual and the asexual generations to alternate. I will +describe as examples the reproduction of a moss, a fern, and a +dicotyledon. + +In such a typical moss as Funaria, we have the following cycle of +developments: The sexual generation is a dioecious leafy structure, +having a central elongated axis, with leaves arranged regularly around +and along it. At the top of the axis in the male plant rise the +antheridia, surrounded by an envelope of modified leaves called the +perigonium. The antheridia are stalked sacs, with a single wall of +cells, and the spiral antherozoids arise by free-cell formation from the +cells of the interior. They are discharged by the bursting of the +antheridium, together with a mucilage formed of the degraded walls of +their mother cells. + +In the female plant there arise at the apex of the stem, surrounded by +an envelope of ordinary leaves, several archegonia. These are of the +ordinary type of those organs, namely, a broad lower portion, containing +a naked oosphere and a long narrow neck with a central canal leading to +the oosphere. Down this canal pass one or more antherozoids, which +become absorbed into the oosphere, and this then secretes a wall, and +from it grows the second or asexual generation. The peculiarity of this +asexual or spore-bearing plant is that it is parasitic on the sexual +plant; the two generations, although not organically connected, yet +remain in close contact, and the spore-bearing generation is at all +events for a time nourished by the leafy sexual generation. + +The spore-bearing generation consists of a long stalk, closely held +below by the cells of the base of the archegonium; this supports a +broadened portion which contains the spores, and the top is covered with +the remains of the neck of the archegonium forming the calyptra. + +The spores arise from special or mother-cells by a process of division, +or it may be even termed free-cell formation, the protoplasm of each +mother-cell dividing into four parts, each of which contracts, secretes +a wall, and thus by rejuvenescence becomes a spore, and by the +absorption of the mother-cells the spores lie loose in the spore sac. +The spores are set free by the bursting of their chamber, and each +germinates, putting out a branched thread of cells called a protonema, +which may perhaps properly be termed a third generation in the cycle of +the plant; for it is only from buds developed on this protonema that the +leafy sexual plant arises. + +The characteristics, then, of the mosses are, that the sexual generation +is leafy, the one or two asexual generations are thalloid, and that the +spore-bearing generation is in parasitic connection with the sexual +generation. + +In the case of the fern, these conditions are very different. + +The sexual generation is a small green thalloid structure called a +prothallium, which bears antheridia and archegonia, each archegonium +having a neck-canal and oosphere, which is fertilized just as in the +moss. + +But the asexual generation derived from the oospore only for a short +while remains in connection with the prothallium, which, of course, +answers to the leafy portion of the moss. What is generally known as the +fern is this asexual generation, a great contrast to the small leafless +moss fruit or sporogonium as it is called, to which it is +morphologically equivalent. On the leaves of this generation arise the +sporangia which contain the spores. The spores are formed in a manner +very similar to those of the mosses, and are set free by rupture of the +sporangium. + +The spore produces the small green prothallium by cell-division in the +usual way, and this completes the cycle of fern life. + +The alternation of generations, which is perhaps most clear and typical +in the case of the fern, becomes less distinctly marked in the plants of +higher organization and type. + +Thus in the Rhizocarpæ there are two kinds of spores, _microspores_ and +_macrospores_, producing prothallia which bear respectively antheridia +and archegonia; in the Lycopodiaceæ, the two kinds of spores produce +very rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the endosperm, in +which archegonia or corpuscula are formed; and lastly, in typical +dicotyledons it is only lately that any trace of a prothallium from the +microspore or pollen cell has been discovered, while the macrospore or +embryo-sac produces only two or three prothallium cells, known as +antipodal cells, and two or three oospheres, known as germinal vesicles. + +This description of the analogies of the pollen and embryo-sac of +dicotyledons assumes that the general vegetative structure of this class +of plants is equivalent to the asexual generation of the higher +cryptogams. In describing their cycle of reproduction I will endeavor to +show grounds for this assumption. + +We start with the embryo as contained in the seed. This embryo is the +product of fertilization of a germinal vesicle by a pollen tube. Hence, +by analogy with the product of fertilization of rhizocarp's, ferns, and +mosses, it should develop into a spore bearing plant. It does develop +into a plant in which on certain modified leaves are produced masses of +tissue in which two kinds of special reproductive cells are formed. This +is precisely analogous to the case of gymnosperms, lycopods, etc., where +on leaf structures are formed macro and micro sporangia. + +To deal first with the microsporangium or pollen-sac. The pollen cells +are formed from mother cells by a process of cell division and +subsequent setting free of the daughter cells or pollen cells by +rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceæ, etc. The subsequent +behavior of the pollen cell, its division and its fertilization of the +germinal vesicle or oosphere, leave no doubt as to its analogy with the +microspore of vascular cryptogams. + +Secondly, the nucleus of the ovule corresponds with the macrosporangium +of Selaginella, through the connecting link of the conifers, where the +ovule is of similar origin and position to the macrosporangium of the +Lycopodiaceæ. But the formation of the macrospore or embryo-sac is +simpler than the corresponding process in cryptogams. It arises by a +simple enlargement of one cell of the nucleus instead of by the division +of one cell into four, each thus becoming a macrospore. At the top of +this macrospore or embryo-sac two or three germinal vesicles are formed +by free cell formation, and also two or three cells called antipodal +cells, since they travel to the other end of the embryo-sac; these +latter represent a rudimentary prothallium. This formation of germinal +vesicles and prothallium seems very different from the formation of +archegonia and prothallium in Selaginella, for instance; but the link +which connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed. + +Thus we see that the flowering plant is essentially the equivalent of +the asexual fern, and of the sporogonium of the moss, and the pollen +cell and the embryo-sac represent the two spores of the higher +cryptogams, and the pollen tube and the germinal vesicles and antipodal +cells are all that remain of the sexual generation, seen in the moss as +a leafy plant, and in the fern as a prothallium. Indeed, when a plant +has monoecious or dioecious flowers, the distinction between the asexual +and the sexual generation has practically been lost, and the +spore-bearing generation has become identified with the sexual +generation. + +Having now described the formation of the pollen and the germinal +vesicles, it only remains to show how they form the embryo. The pollen +cell forms two or three divisions, which are either permanent or soon +absorbed; this, as before stated, is the rudimentary male prothallium. +Then when it lies on the stigma it develops a long tube, which passes +down the style and through the micropyle of the ovule to the germinal +vesicles, one of which is fertilized by what is probably an osmotic +transference of nuclear matter. The germinal vesicle now secretes a +wall, divides into two parts, and while the rest of the embyro-sac fills +with endosperm cells, it produces by cell division from the upper half a +short row of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or leafy +plant, and while in the fern each generation is an independent +structure, here in the dicotyledon, on the other hand, the asexual +generation or embryo is again for a time nourished in the interior of +the embryo-sac representing the sexual generation, and this again +derives its nourishment from the previous asexual generation, so that as +in the moss, there is again a partial parasitism of one generation on +the other. + +To sum up the methods of plant reproduction: They resolve themselves +into two classes. + +1st. Purely vegetative. + +2d. Truly reproductive by special cells. + +In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive methods. + +1st. Reproduction from an asexual spore. + +2d. Reproduction from an oospore formed by the combination of two sexual +cells. + +In the vast majority of plant species these two types are used by the +individuals alternately. + +The extraordinary similarity of the reproductive process, as shown in +the examples I have given, Achlya, Spirogyra, and Vaucheria among algæ, +the moss, the fern, and the flowering plant, a similarity which becomes +the more marked the more the details of each case and of the cases of +plants which form links between these great classes are studied, points +to a community of origin of all plants in some few or one primeval +ancestor. And to this inference the study of plant structure and +morphology, together with the evidence of palæobotany among other +circumstances, lends confirmatory evidence, and all modern discoveries, +as for instance that of the rudimentary prothallium formed by the pollen +of angiosperms, tend to the smoothing of the path by which the descent +of the higher plants from simpler types will, as I think, be eventually +shown. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +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. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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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, Vol. XXI., No. 531, March 6, 1886 + +Author: Various + +Release Date: February 29, 2004 [EBook #11383] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPP. 531 *** + + + + +Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland, +Charles Franks and the DP Team + + + + + + +</pre> + +<p class="ctr"><a href="./illustrations/1a.png"><img src= +"./illustrations/1a_th.jpg" alt=""></a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 531</h1> + +<h2>NEW YORK, MARCH 6, 1886</h2> + +<h4>Scientific American Supplement. Vol. XXI, No. 531.</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 AND METALLURGY.--Annatto.-Analyses of +the same.--By WM. LAWSON</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#2">Aluminum.--By J.A. PRICE.--Iron the basis of +civilization.-- Aluminum the metal of the future.--Discovery of +aluminum.--Art of obtaining the metal.--Uses and +possibilities</a></td> +</tr> + +<tr> +<td valign="top">II.</td> +<td><a href="#3">ENGINEERING AND MECHANICS.--The Use of Iron in +Fortification. --Armor-plated casements.--The Schumann-Gruson +chilled iron cupola.--Mougin's rolled iron cupola.--With full page +of engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#4">High Speed on the Ocean</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#5">Sibley College Lectures.--Principles and Methods +of Balancing Forces developed in Moving Bodies.--Momentum and +centrifugal force.--By CHAS.T. PORTER.--3 figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#6">Compressed Air Power Schemes.--By J. +STURGEON.--Several figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#7">The Berthon Collapsible Canoe.--2 +engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#8">The Fiftieth Anniversary of the Opening of the +First German Steam Railroad.--With full page engraving</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#9">Improved Coal Elevator.--With engraving</a></td> +</tr> + +<tr> +<td valign="top">III.</td> +<td><a href="#10">TECHNOLOGY.--Steel-making Ladles.--4 +figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#11">Water Gas.--The relative value of water gas and +other gases as Iron-reducing Agents.--By B.H. +THWAITE.--Experiments.--With tables and 1 figure</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#12">Japanese Rice Wine and Soja Sauce.--Method of +making</a></td> +</tr> + +<tr> +<td valign="top">IV.</td> +<td><a href="#13">ELECTRICITY, MICROSCOPY, ETC.-Apparatus for +demonstrating that Electricity develops only on the Surface of +Conductors.--1 figure</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#14">The Colson Telephone.--3 engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#15">The Meldometer.--An apparatus for determining the +melting points of minerals</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#16">Touch Transmission by Electricity in the +Education of Deaf Mutes.--By S. TEFFT WALKER.--With 1 +figure</a></td> +</tr> + +<tr> +<td valign="top">V.</td> +<td><a href="#17">HORTICULTURE.--Candelabra Cactus and the +California Woodpecker.--By C.F. HOLDER.--With 2 engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#18">How Plants are reproduced.--By C.E. STUART.--A +paper read before the Chemists' Assistants' Association</a></td> +</tr> + +<tr> +<td valign="top">VI.</td> +<td><a href="#19">MISCELLANEOUS--The Origin of Meteorites.--With 1 +figure</a></td> +</tr> +</table> + +<hr> +<p><a name="3"></a></p> + +<h2>THE USE OF IRON IN FORTIFICATION.</h2> + +<p>Roumania is thinking of protecting a portion of the artillery of +the forts surrounding her capital by metallic cupolas. But, before +deciding upon the mode of constructing these formidable and costly +affairs, and before ordering them, she has desired to ascertain +their efficacy and the respective merits of the chilled iron armor +which was recently in fashion and of rolled iron, which looks as if +it were to be the fashion hereafter.</p> + +<p class="ctr"><a href="./illustrations/1b.png"><img src= +"./illustrations/1b_th.jpg" alt= +"FIG. 1.--MOUGIN'S ROLLED IRON TURRET."></a></p> + +<p class="ctr">FIG. 1.--MOUGIN'S ROLLED IRON TURRET.</p> + +<p>The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a +turret of rolled iron. Both of these recommend themselves by +various merits, and by remarkably ingenious arrangements, and it +only remains to be seen how they will behave under the fire of the +largest pieces of artillery.</p> + +<p class="ctr"><img src="./illustrations/1c.png" alt="FIG. 2."></p> + +<p class="ctr">FIG. 2.</p> + +<p>We are far in advance of the time when cannons with smooth bore +were obliged to approach to within a very short range of a scarp in +order to open a breach, and we are far beyond that first rifled +artillery which effected so great a revolution in tactics.</p> + +<p class="ctr"><img src="./illustrations/1d.png" alt="FIG. 3."></p> + +<p class="ctr">FIG. 3.</p> + +<p>To-day we station the batteries that are to tear open a rampart +at distances therefrom of from 1,000 to 2,000 yards, and the long, +6 inch cannon that arms them has for probable deviations, under a +charge of 20 pounds of powder, and at a distance of 1,000 yards, 28 +feet in range, 16 inches in direct fire and 8 inches in curved.</p> + +<p>The weight of the projectile is 88 pounds, and its remanent +velocity at the moment of impact is 1,295 feet. Under this enormous +live force, the masonry gradually crumbles, and carries along the +earth of the parapet, and opens a breach for the assaulting +columns.</p> + +<p class="ctr"><img src="./illustrations/1e.png" alt=""></p> + +<p class="ctr">FIG. 4--STATE OF A CUPOLA AFTER THE<br> +ACTION OF THIRTY-SEVEN 6 IN. PROJECTILES.</p> + +<p>In order to protect the masonry of the scarp, engineers first +lowered the cordon to the level of the covert-way. Under these +circumstances, the enemy, although he could no longer see it, +reached it by a curved or "plunging" shot. When, in fact, for a +given distance we load a gun with the heaviest charge that it will +stand, the trajectory, AMB (Fig. 2), is as depressed as possible, +and the angles, a and a', at the start and arrival are small, and +we have a direct shot. If we raise the chase of the piece, the +projectile will describe a curve in space which would be a perfect +parabola were it not for the resistance of the air, and the summit +of such curve will rise in proportion as the angle so increases. So +long as the falling angle, a, remains less than 45°, we shall +have a curved shot. When the angle exceeds this, the shot is called +"vertical." If we preserve the same charge, the parabolic curve in +rising will meet the horizontal plane at a greater distance off. +This is, as well known, the process employed for reaching more and +more distant objects.</p> + +<p class="ctr"><img src="./illustrations/1f.png" alt=""></p> + +<p class="ctr">Fig. 5.--STATE OF A CAST-IRON CUPOLA<br> +AFTER THE BREAKAGE OF A VOUSSOIR.</p> + +<p>The length of a gun depends upon the maximum charge burned in +it, since the combustion must be complete when the projectile +reaches the open air. It results from this that although guns of +great length are capable of throwing projectiles with small +charges, it is possible to use shorter pieces for this +purpose--such as howitzers for curved shots and mortars for +vertical ones. The curved shot finds one application in the opening +of breaches in scarp walls, despite the existence of a covering of +great thickness. If, from a point, a (Fig. 3), we wish to strike +the point, b, of a scarp, over the crest, c, of the covert-way, it +will suffice to pass a parabolic curve through these three +points--the unknown data of the problem, and the charge necessary, +being ascertained, for any given piece, from the artillery tables. +In such cases it is necessary to ascertain the velocity at the +impact, since the force of penetration depends upon the live force +(mv²) of the projectile, and the latter will not penetrate +masonry unless it have sufficient remanent velocity. Live force, +however, is not the sole factor that intervenes, for it is +indispensable to consider the angle at which the projectile strikes +the wall. Modern guns, such as the Krupp 6 inch and De Bange 6 and +8 inch, make a breach, the two former at a falling angle of +22°, and the latter at one of 30°. It is not easy to lower +the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass +of the glacis.</p> + +<p>The same guns are employed for dismounting the defender's +pieces, which he covers as much as possible behind the parapet. +Heavy howitzers destroy the <i>materiel</i>, while shrapnel, +falling nearly vertically, and bursting among the men, render all +operations impossible upon an open terre-plein.</p> + +<p class="ctr"><img src="./illustrations/1g.png" alt=""></p> + +<p class="ctr">FIG. 6.--STATE OF A CHILLED IRON CUPOLA<br> +BROKEN BY A 12 INCH BALL.</p> + +<p>The effect of 6 and 8 inch rifled mortars is remarkable. The +Germans have a 9 inch one that weighs 3,850 pounds, and the +projectile of which weighs 300. But French mortars in nowise cede +to those of their neighbors; Col. De Bange, for example, has +constructed a 10½ inch one of wonderful power and +accuracy.</p> + +<p>Seeing the destructive power of these modern engines of war, it +may well be asked how many pieces the defense will be able to +preserve intact for the last period of a siege--for the very moment +at which it has most need of a few guns to hold the assailants in +check and destroy the assaulting columns. Engineers have proposed +two methods of protecting these few indispensable pieces. The first +of these consists in placing each gun under a masonry vault, which +is covered with earth on all sides except the one that contains the +embrasure, this side being covered with armor plate.</p> + +<p>The second consists in placing one or two guns under a metallic +cupola, the embrasures in which are as small as possible. The +cannon, in a vertical aim, revolves around the center of an +aperture which may be of very small dimensions. As regards direct +aim, the carriages are absolutely fixed to the cupola, which itself +revolves around a vertical axis. These cupolas may be struck in +three different ways: (1) at right angles, by a direct shot, and +consequently with a full charge--very dangerous blows, that +necessitate a great thickness of the armor plate; (2) obliquely, +when the projectile, if the normal component of its real velocity +is not sufficient to make it penetrate, will be deflected without +doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy.</p> + +<p>General Brialmont says that the metal of the cupola should be +able to withstand both penetration and breakage; but these two +conditions unfortunately require opposite qualities. A metal of +sufficient ductility to withstand breakage is easily penetrated, +and, conversely, one that is hard and does not permit of +penetration does not resist shocks well. Up to the present, +casehardened iron (Gruson) has appeared to best satisfy the +contradictory conditions of the problem. Upon the tempered exterior +of this, projectiles of chilled iron and cast steel break upon +striking, absorbing a part of their live force for their own +breakage.</p> + +<p>In 1875 Commandant Mougin performed some experiments with a +chilled iron turret established after these plans. The thickness of +the metal normally to the blows was 23½ inches, and the +projectiles were of cast steel. The trial consisted in firing two +solid 12 in. navy projectiles, 46 cylindrical 6 in. ones, weighing +100 lb., and 129 solid, pointed ones, 12 in. in diameter. The 6 +inch projectiles were fired from a distance of 3,280 feet, with a +remanent velocity of 1,300 feet. The different phases of the +experiment are shown in Figs. 4, 5, and 6. The cupola was broken; +but it is to be remarked that a movable and well-covered one would +not have been placed under so disadvantageous circumstances as the +one under consideration, upon which it was easy to superpose the +blows. An endeavor was next made to substitute a tougher metal for +casehardened iron, and steel was naturally thought of. But hammered +steel broke likewise, and a mixed or compound metal was still less +successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was +rolled iron. Armor plate composed of this latter has been submitted +to several tests, which appear to show that a thickness of 18 +inches will serve as a sufficient barrier to the shots of any gun +that an enemy can conveniently bring into the field.</p> + +<p class="ctr"><img src="./illustrations/1h.png" alt=""></p> + +<p class="ctr">FIG. 7.--CASEMATE OF CHILLED IRON AFTER<br> +RECEIVING NINETY-SIX SHOTS.</p> + +<p><i>Armor Plated Casemates</i>.--Fig. 7 shows the state of a +chilled iron casemate after a vigorous firing. The system that we +are about to describe is much better, and is due to Commandant +Mougin.</p> + +<p class="ctr"><a href="./illustrations/1i.png"><img src= +"./illustrations/1i_th.jpg" alt= +"FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE."></a></p> + +<p class="ctr">FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.</p> + +<p>The gun is placed under a vault whose generatrices are at right +angles to the line of fire (Fig. 8), and which contains a niche +that traverses the parapet. This niche is of concrete, and its +walls in the vicinity of the embrasure are protected by thick iron +plate. The rectangular armor plate of rolled iron rests against an +elastic cushion of sand compactly rammed into an iron plate +caisson. The conical embrasure traverses this cushion by means of a +cast-steel piece firmly bolted to the caisson, and applied to the +armor through the intermedium of a leaden ring. Externally, the +cheeks of the embrasure and the merlons consist of blocks of +concrete held in caissons of strong iron plate. The surrounding +earthwork is of sand. For closing the embrasure, Commandant Mougin +provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected +by the sloping mass of concrete that covers the head of the +casemate. A windlass and chain give the disk the motion that brings +one of its apertures opposite the embrasure or that closes the +latter. When this portion of the disk has suffered too much from +the enemy's fire, a simple maneuver gives it a half revolution, and +the second aperture is then made use of.</p> + +<p><i>The Schumann-Gruson Chilled Iron Cupola</i>.--This cupola +(Fig. 9) is dome-shaped, and thus offers but little surface to +direct fire; but it can be struck by a vertical shot, and it may be +inquired whether its top can withstand the shock of projectiles +from a 10 inch rifled mortar. It is designed for two 6 inch guns +placed parallel. Its internal diameter is 19½ feet, and the +dome is 8 inches in thickness and has a radius of 16½ feet. +It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of +relatively small bulk--a bad feature as regards resistance to +shock. To obviate this difficulty, the inventor partitions it +internally in such a way as to leave only sufficient space to +maneuver the guns. The partitions consist of iron plate boxes +filled with concrete. The form of the dome has one inconvenience, +viz., the embrasure in it is necessarily very oblique, and offers +quite an elongated ellipse to blows, and the edges of the bevel +upon a portion of the circumference are not strong enough. In order +to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides +of the embrasure. The motion of the piece necessary to aim it +vertically is effected around this axis of rotation. The weight of +the gun is balanced by a system of counterpoises and the chains, l, +and the breech terminates in a hollow screw, f, and a nut, g, held +between two directing sectors, h. The cupola is revolved by simply +acting upon the rollers.</p> + +<p class="ctr"><img src="./illustrations/1j.png" alt= +"FIG. 9.--THE SCHUMANN-GRUSON CUPOLA."></p> + +<p class="ctr">FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.</p> + +<p><i>Mougin's Rolled Iron Cupola</i>.--The general form of this +cupola (Fig. 1) is that of a cylindrical turret. It is 12¾ +feet in diameter, and rises 3¼ feet above the top of the +glacis. It has an advantage over the one just described in +possessing more internal space, without having so large a diameter; +and, as the embrasures are at right angles with the sides, the +plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of +strong iron plate strengthened by angle irons. Vertical partitions +under the cheeks of the gun carriages serve as cross braces, and +are connected with each other upon the table of the hydraulic pivot +around which the entire affair revolves. This pivot terminates in a +plunger that enters a strong steel press-cylinder embedded in the +masonry of the lower concrete vault.</p> + +<p>The iron plate ring carries wheels and rollers, through the +intermedium of which the turret is revolved. The circular iron +track over which these move is independent of the outer armor.</p> + +<p>The whole is maneuvered through the action of one man upon the +piston of a very small hydraulic press. The guns are mounted upon +hydraulic carriages. The brake that limits the recoil consists of +two bronze pump chambers, a and b (Fig. 10). The former of these is +4 inches in diameter, and its piston is connected with the gun, +while the other is 8 inches in diameter, and its piston is +connected with two rows of 26 couples of Belleville springs, d. The +two cylinders communicate through a check valve.</p> + +<p>When the gun is in battery, the liquid fills the chamber of the +4 inch pump, while the piston of the 8 inch one is at the end of +its stroke. A recoil has the effect of driving in the 4 inch piston +and forcing the liquid into the other chamber, whose piston +compresses the springs. At the end of the recoil, the gunner has +only to act upon the valve by means of a hand-wheel in order to +bring the gun into battery as slowly as he desires, through the +action of the springs.</p> + +<p class="ctr"><img src="./illustrations/2a.png" alt=""></p> + +<p class="ctr">FIG. 10.--MOUGIN'S HYDRAULIC GUN<br> +CARRIAGE.</p> + +<p>For high aiming, the gun and the movable part of its carriage +are capable of revolving around a strong pin, c, so placed that the +axis of the piece always passes very near the center of the +embrasure, thus permitting of giving the latter minimum dimensions. +The chamber of the 8 inch pump is provided with projections that +slide between circular guides, and carries the strap of a small +hydraulic piston, p, that suffices to move the entire affair in a +vertical plane, the gun and movable carriage being balanced by a +counterpoise, q.</p> + +<p>The projectiles are hoisted to the breech of the gun by a +crane.</p> + +<p>Between the outer armor and turret sufficient space is left for +a man to enter, in order to make repairs when necessary.</p> + +<p>Each of the rolled iron plates of which the turret consists +weighs 19 tons. The cupolas that we have examined in this article +have been constructed on the hypothesis than an enemy will not be +able to bring into the field guns of much greater caliber than 6 +inches.--<i>Le Genie Civil</i>.</p> + +<hr> +<p><a name="4"></a></p> + +<h2>HIGH SPEED ON THE OCEAN.</h2> + +<p><i>To the Editor of the Scientific American</i>:</p> + +<p>Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN +of Jan. 2, 1886, in regard to high speed on the ocean.</p> + +<p>Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the +plane of their motion, but at an angle to it, the same principle +would, if applied to a steamship, increase its speed. But let us +look at the subject from another standpoint. The quadruped has to +support the weight of his body, and propel himself forward, with +the same force. If the force be applied perpendicularly, the body +is elevated, but not moved forward. If the force is applied +horizontally, the body moves forward, but soon falls to the ground, +because it is not supported. But when the force is applied at the +proper angle, the body is moved forward and at the same time +supported. Directly contrary to Capt. Giles' theory, the greater +the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and <i>vice versa</i>. +This may easily be seen by any one watching the motions of the +horse, hound, deer, rabbit, etc., when in rapid motion. The water +birds and animals, whose weight is supported by the water, do not +exert the propulsive force in a downward direction, but in a direct +line with the plane of their motion. The man who swims does not +increase his motion by kicking out at an angle, but by drawing the +feet together with the legs straight, thus using the water between +them as a double inclined plane, on which his feet and legs slide +and thus increase his motion. The weight of the steamship is +already supported by the water, and all that is required of the +propeller is to push her forward. If set so as to act in a direct +line with the plane of motion, it will use all its force to push +her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. +If placed at an angle of 45° with the plane of motion, half the +force will be used in raising the ship out of the water, and only +half will be left to push her forward.</p> + +<p>ENOS M. RICKER.</p> + +<p>Park Rapids, Minn., Jan. 23, 1886.</p> + +<hr> +<h2>SIBLEY COLLEGE LECTURES.</h2> + +<h3>BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING.</h3> + +<p><a name="5"></a></p> + +<h2>PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES.</h2> + +<h3>BY CHAS. T. PORTER.</h3> + +<h3>INTRODUCTION.</h3> + +<p>On appearing for the first time before this Association, which, +as I am informed, comprises the faculty and the entire body of +students of the Sibley College of Mechanical Engineering and the +Mechanic Arts, a reminiscence of the founder of this College +suggests itself to me, in the relation of which I beg first to be +indulged.</p> + +<p>In the years 1847-8-9 I lived in Rochester, N.Y., and formed a +slight acquaintance with Mr. Sibley, whose home was then, as it has +ever since been, in that city. Nearly twelve years afterward, in +the summer of 1861, which will be remembered as the first year of +our civil war, I met Mr. Sibley again. We happened to occupy a seat +together in a car from New York to Albany. He recollected me, and +we had a conversation which made a lasting impression on my memory. +I said we had a conversation. That reminds me of a story told by my +dear friend, of precious memory, Alexander L. Holley. One summer +Mr. Holley accompanied a party of artists on an excursion to Mt. +Katahdin, which, as you know, rises in almost solitary grandeur +amid the forests and lakes of Maine. He wrote, in his inimitably +happy style, an account of this excursion, which appeared some time +after in <i>Scribner's Monthly</i>, elegantly illustrated with +views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. +Katahdin. "That is," he explained, "Mr. Church painted, and I held +the umbrella."</p> + +<p>This describes the conversation which Mr. Sibley and I had. Mr. +Sibley talked, and I listened. He was a good talker, and I flatter +myself that I rather excel as a listener. On that occasion I did my +best, for I knew whom I was listening to. I was listening to the +man who combined bold and comprehensive grasp of thought, unerring +foresight and sagacity, and energy of action and power of +accomplishment, in a degree not surpassed, if it was equaled, among +men.</p> + +<p>Some years before, Mr. Sibley had created the Western Union +Telegraph Company. At that time telegraphy was in a very depressed +state. The country was to a considerable extent occupied by local +lines, chartered under various State laws, and operated without +concert. Four rival companies, organized under the Morse, the Bain, +the House, and the Hughes patents, competed for the business. +Telegraph stock was nearly valueless. Hiram Sibley, a man of the +people, a resident of an inland city, of only moderate fortune, +alone grasped the situation. He saw that the nature of the +business, and the demands of the country, alike required that a +single organization, in which all interests should be combined, +should cover the entire land with its network, by means of which +every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this +vividly, and realized it with the most intense earnestness of +conviction. With Mr. Sibley, to be convinced was to act; and so he +set about the task of carrying this vast scheme into execution. The +result is well known. By his immense energy, the magnetic power +with which he infused his own convictions into other minds, the +direct, practical way in which he set about the work, and his +indomitable perseverance, Mr. Sibley attained at last a phenomenal +success.</p> + +<p>But he was not then telling me anything about this. He was +telling me of the construction of the telegraph line to the Pacific +Coast. Here again Mr. Sibley had seen that which was hidden from +others. This case differed from the former one in two important +respects. Then Mr. Sibley had been dependent on the aid and +co-operation of many persons; and this he had been able to secure. +Now, he could not obtain help from a human being; but he had become +able to act independently of any assistance.</p> + +<p>He had made a careful study of the subject, in his thoroughly +practical way, and had become convinced that such a line was +feasible, and would be remunerative. At his instance a convention +of telegraph men met in the city of New York, to consider the +project. The feeling in this convention was extremely unfavorable +to it. A committee reported against it unanimously, on three +grounds--the country was destitute of timber, the line would be +destroyed by the Indians, and if constructed and maintained, it +would not pay expenses. Mr. Sibley found himself alone. An earnest +appeal which he made from the report of the committee was received +with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and +two thousand miles of its breadth by bands of savages, who of +course would destroy the line as soon as it was put up, and where +repairs would be difficult and useless, even if the other +objections to it were out of the way, struck the members of the +convention as so exquisitely ludicrous that it seemed as if they +would never be done laughing about it. If Mr. Sibley had advocated +a line to the moon, they would hardly have seen in it greater +evidence of lunacy. When he could be heard, he rose again and said: +"Gentlemen, you may laugh, but if I was not so old, I would build +the line myself." Upon this, of course, they laughed louder than +ever. As they laughed, he grew mad, and shouted: "Gentlemen, I will +bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon +it scouted the project as chimerical, and no capitalist would put a +dollar in it, Hiram Sibley built the line of telegraph to San +Francisco, risking in it all he had in the world. He set about the +work with his customary energy, all obstacles vanished, and the +line was completed in an incredibly short time. And from the day it +was opened, it has proved probably the most profitable line of +telegraph that has ever been constructed. There was the +practicability, and there was the demand and the business to be +done, and yet no living man could see it, or could be made to see +it, except Hiram Sibley. "And to-day," he said, with honest pride, +"to-day in New York, men to whom I went almost on my knees for help +in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one."</p> + +<p>"But how about the Indians?" I asked. "Why," he replied, "we +never had any trouble from the Indians. I knew we wouldn't have. +Men who supposed I was such a fool as to go about this undertaking +before that was all settled didn't know me. No Indian ever harmed +that line. The Indians are the best friends we have got. You see, +we taught the Indians the Great Spirit was in that line; and what +was more, we proved it to them. It was, by all odds, the greatest +medicine they ever saw. They fairly worshiped it. No Indian ever +dared to do it harm."</p> + +<p>"But," he added, "there was one thing I didn't count on. The +border ruffians in Missouri are as bad as anybody ever feared the +Indians might be. They have given us so much trouble that we are +now building a line around that State, through Iowa and Nebraska. +We are obliged to do it."</p> + +<p>This opened another phase of the subject. The telegraph line to +the Pacific had a value beyond that which could be expressed in +money. It was perhaps the strongest of all the ties which bound +California so securely to the Union, in the dark days of its +struggle for existence. The secession element in Missouri +recognized the importance of the line in this respect, and were +persistent in their efforts to destroy it. We have seen by what +means their purpose was thwarted.</p> + +<p>I have always felt that, among the countless evidences of the +ordering of Providence by which the war for the preservation of the +Union was signalized, not the least striking was the raising up of +this remarkable man, to accomplish alone, and in the very nick of +time, a work which at once became of such national importance.</p> + +<p>This is the man who has crowned his useful career, and shown +again his eminently practical character and wise foresight, by the +endowment of this College, which cannot fail to be a perennial +source of benefit to the country whose interests he has done so +much to promote, and which his remarkable sagacity and energy +contributed so much to preserve.</p> + +<p>We have an excellent rule, followed by all successful designers +of machinery, which is, to make provision for the extreme case, for +the most severe test to which, under normal conditions, and so far +as practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than +the extreme demand are not likely to give trouble. I shall apply +this principle in addressing you to-day. In what I have to say, I +shall speak directly to the youngest and least advanced minds among +my auditors. If I am successful in making an exposition of my +subject which shall be plain to them, then it is evident that I +need not concern myself about being understood by the higher class +men and the professors.</p> + +<p>The subject to which your attention is now invited is</p> + +<h3>THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN +MOVING BODIES.</h3> + +<p>This is a subject with which every one who expects to be +concerned with machinery, either as designer or constructor, ought +to be familiar. The principles which underlie it are very simple, +but in order to be of use, these need to be thoroughly understood. +If they have once been mastered, made familiar, incorporated into +your intellectual being, so as to be readily and naturally applied +to every case as it arises, then you occupy a high vantage ground. +In this particular, at least, you will not go about your work +uncertainly, trying first this method and then that one, or leaving +errors to be disclosed when too late to remedy them. On the +contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what +you intend.</p> + +<p>Moreover, when you read discussions on any branch of this +subject, you will not receive these into unprepared minds, just as +apt to admit error as truth, and possessing no test by which to +distinguish the one from the other; but you will be able to form +intelligent judgments with respect to them. You will discover at +once whether or not the writers are anchored to the sure holding +ground of sound principles.</p> + +<p>It is to be observed that I do not speak of balancing bodies, +but of balancing forces. Forces are the realities with which, as +mechanical engineers, you will have directly to deal, all through +your lives. The present discussion is limited also to those forces +which are developed in moving bodies, or by the motion of bodies. +This limitation excludes the force of gravity, which acts on all +bodies alike, whether at rest or in motion. It is, indeed, often +desirable to neutralize the effect of gravity on machinery. The +methods of doing this are, however, obvious, and I shall not +further refer to them.</p> + +<p>Two very different forces, or manifestations of force, are +developed by the motion of bodies. These are</p> + +<h3>MOMENTUM AND CENTRIFUGAL FORCE.</h3> + +<p>The first of these forces is exerted by every moving body, +whatever the nature of the path in which it is moving, and always +in the direction of its motion. The latter force is exerted only by +bodies whose path is a circle, or a curve of some form, about a +central body or point, to which it is held, and this force is +always at right angles with the direction of motion of the +body.</p> + +<p>Respecting momentum, I wish only to call your attention to a +single fact, which will become of importance in the course of our +discussion. Experiments on falling bodies, as well as all +experience, show that the velocity of every moving body is the +product of two factors, which must combine to produce it. Those +factors are force and distance. In order to impart motion to the +body, force must act through distance. These two factors may be +combined in any proportions whatever. The velocity imparted to the +body will vary as the square root of their product. Thus, in the +case of any given body,</p> + +<pre> + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. +</pre> + +<p>This table might be continued indefinitely. The product of the +force into the distance will always vary as the square of the final +velocity imparted. To arrest a given velocity, the same force, +acting through the same distance, or the same product of force into +distance, is required that was required to impart the velocity.</p> + +<p>The fundamental truth which I now wish to impress upon your +minds is that in order to impart velocity to a body, to develop the +energy which is possessed by a body in motion, force must act +through distance. Distance is a factor as essential as force. +Infinite force could not impart to a body the least velocity, could +not develop the least energy, without acting through distance.</p> + +<p>This exposition of the nature of momentum is sufficient for my +present purpose. I shall have occasion to apply it later on, and to +describe the methods of balancing this force, in those cases in +which it becomes necessary or desirable to do so. At present I will +proceed to consider the second of the forces, or manifestations of +force, which are developed in moving bodies--<i>centrifugal +force</i>.</p> + +<p>This force presents its claims to attention in all bodies which +revolve about fixed centers, and sometimes these claims are +presented with a good deal of urgency. At the same time, there is +probably no subject, about which the ideas of men generally are +more vague and confused. This confusion is directly due to the +vague manner in which the subject of centrifugal force is treated, +even by our best writers. As would then naturally be expected, the +definitions of it commonly found in our handbooks are generally +indefinite, or misleading, or even absolutely untrue.</p> + +<p>Before we can intelligently consider the principles and methods +of balancing this force, we must get a correct conception of the +nature of the force itself. What, then, is centrifugal force? It is +an extremely simple thing; a very ordinary amount of mechanical +intelligence is sufficient to enable one to form a correct and +clear idea of it. This fact renders it all the more surprising that +such inaccurate and confused language should be employed in its +definition. Respecting writers, also, who use language with +precision, and who are profound masters of this subject, it must be +said that, if it had been their purpose to shroud centrifugal force +in mystery, they could hardly have accomplished this purpose more +effectually than they have done, to minds by whom it was not +already well understood.</p> + +<p>Let us suppose a body to be moving in a circular path, around a +center to which it is firmly held; and let us, moreover, suppose +the impelling force, by which the body was put in motion, to have +ceased; and, also, that the body encounters no resistance to its +motion. It is then, by our supposition, moving in its circular path +with a uniform velocity, neither accelerated nor retarded. Under +these conditions, what is the force which is being exerted on this +body? Clearly, there is only one such force, and that is, the force +which holds it to the center, and compels it, in its uniform +motion, to maintain a fixed distance from this center. This is what +is termed centripetal force. It is obvious, that the centripetal +force, which holds this revolving body <i>to</i> the center, is the +only force which is being exerted upon it.</p> + +<p>Where, then, is the centrifugal force? Why, the fact is, there +is not any such thing. In the dynamical sense of the term "force," +the sense in which this term is always understood in ordinary +speech, as something tending to produce motion, and the direction +of which determines the direction in which motion of a body must +take place, there is, I repeat, no such thing as centrifugal +force.</p> + +<p>There is, however, another sense in which the term "force" is +employed, which, in distinction from the above, is termed a +statical sense. This "statical force" is the force by the exertion +of which a body keeps still. It is the force of inertia--the +resistance which all matter opposes to a dynamical force exerted to +put it in motion. This is the sense in which the term "force" is +employed in the expression "centrifugal force." Is that all? you +ask. Yes; that is all.</p> + +<p>I must explain to you how it is that a revolving body exerts +this resistance to being put in motion, when all the while it +<i>is</i> in motion, with, according to our above supposition, a +uniform velocity. The first law of motion, so far as we now have +occasion to employ it, is that a body, when put in motion, moves in +a straight line. This a moving body always does, unless it is acted +on by some force, other than its impelling force, which deflects +it, or turns it aside, from its direct line of motion. A familiar +example of this deflecting force is afforded by the force of +gravity, as it acts on a projectile. The projectile, discharged at +any angle of elevation, would move on in a straight line forever, +but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made +to fall, by the attraction of the earth; and so instead of a +straight line it describes a curve, known as the trajectory.</p> + +<p>Now a revolving body, also, has the same tendency to move in a +straight line. It would do so, if it were not continually deflected +from this line. Another force is constantly exerted upon it, +compelling it, at every successive point of its path, to leave the +direct line of motion, and move on a line which is everywhere +equally distant from the center to which it is held. If at any +point the revolving body could get free, and sometimes it does get +free, it would move straight on, in a line tangent to the circle at +the point of its liberation. But if it cannot get free, it is +compelled to leave each new tangential direction, as soon as it has +taken it.</p> + +<p>This is illustrated in the above figure. The body, A, is +supposed to be revolving in the direction indicated by the arrow, +in the circle, A B F G, around the center, O, to which it is held +by the cord, O A. At the point, A, it is moving in the tangential +direction, A D. It would continue to move in this direction, did +not the cord, O A, compel it to move in the arc, A C. Should this +cord break at the point, A, the body would move; straight on toward +D, with whatever velocity it had.</p> + +<p>You perceive now what centrifugal force is. This body is moving +in the direction, A D. The centripetal force, exerted through the +cord, O A, pulls it aside from this direction of motion. The body +resists this deflection, and this resistance is its centrifugal +force.</p> + +<p class="ctr"><img src="./illustrations/3a.png" alt="Fig. 1"></p> + +<p class="ctr">Fig. 1</p> + +<p>Centrifugal force is, then, properly defined to be the +disposition of a revolving body to move in a straight line, and the +resistance which such a body opposes to being drawn aside from a +straight line of motion. The force which draws the revolving body +continually to the center, or the deflecting force, is called the +centripetal force, and, aside from the impelling and retarding +forces which act in the direction of its motion, the centripetal +force is, dynamically speaking, the only force which is exerted on +the body.</p> + +<p>It is true, the resistance of the body furnishes the measure of +the centripetal force. That is, the centripetal force must be +exerted in a degree sufficient to overcome this resistance, if the +body is to move in the circular path. In this respect, however, +this case does not differ from every other case of the exertion of +force. Force is always exerted to overcome resistance: otherwise it +could not be exerted. And the resistance always furnishes the exact +measure of the force. I wish to make it entirely clear, that in the +dynamical sense of the term "force," there is no such thing as +centrifugal force. The dynamical force, that which produces motion, +is the centripetal force, drawing the body continually from the +tangential direction, toward the center; and what is termed +centrifugal force is merely the resistance which the body opposes +to this deflection, <i>precisely like any other resistance to a +force</i>.</p> + +<p>The centripetal force is exerted on the radial line, as on the +line, A O, Fig. 1, at right angles with the direction in which the +body is moving; and draws it directly toward the center. It is, +therefore, necessary that the resistance to this force shall also +be exerted on the same line, in the opposite direction, or directly +from the center. But this resistance has not the least power or +tendency to produce motion in the direction in which it is exerted, +any more than any other resistance has.</p> + +<p>We have been supposing a body to be firmly held to the center, +so as to be compelled to revolve about it in a fixed path. But the +bond which holds it to the center may be elastic, and in that case, +if the centrifugal force is sufficient, the body will be drawn from +the center, stretching the elastic bond. It may be asked if this +does not show centrifugal force to be a force tending to produce +motion from the center. This question is answered by describing the +action which really takes place. The revolving body is now +imperfectly deflected. The bond is not strong enough to compel it +to leave its direct line of motion, and so it advances a certain +distance along this tangential line. This advance brings the body +into a larger circle, and by this enlargement of the circle, +assuming the rate of revolution to be maintained, its centrifugal +force is proportionately increased. The deflecting power exerted by +the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct +path; and when the limit of its elasticity is reached, the +deflecting bond will be broken. If, however, the strength of the +deflecting bond is increased by its elongation in a more rapid +ratio than the centrifugal force is increased by the enlargement of +the circle, then a point will be reached in which the centripetal +force will be sufficient to compel the body to move again in the +circular path.</p> + +<p>Sometimes the centripetal force is weak, and opportunity is +afforded to observe this action, and see its character exhibited. A +common example of weak centripetal force is the adhesion of water +to the face of a revolving grindstone. Here we see the deflecting +force to become insufficient to compel the drops of water longer to +leave their direct paths, and so these do not longer leave their +direct paths, but move on in those paths, with the velocity they +have at the instant of leaving the stone, flying off on tangential +lines.</p> + +<p>If, however, a fluid be poured on the side of the revolving +wheel near the axis, it will move out to the rim on radial lines, +as may be observed on car wheels universally. The radial lines of +black oil on these wheels look very much as if centrifugal force +actually did produce motion, or had at least a very decided +tendency to produce motion, in the radial direction. This +interesting action calls for explanation. In this action the oil +moves outward gradually, or by inconceivably minute steps. Its +adhesion being overcome in the least possible degree, it moves in +the same degree tangentially. In so doing it comes in contact with +a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it +had overcome the adhesion. Motion in the radial direction is the +result of these two actions, namely, leaving the first point of +contact tangentially and receiving an acceleration of its motion, +so that this shall be equal to that of the second point of contact. +When we think about the matter a little closely, we see that at the +rim of the wheel the oil has perhaps ten times the velocity of +revolution which it had on leaving the journal, and that the +mystery to be explained really is, How did it get that velocity, +moving out on a radial line? Why was it not left behind at the very +first? Solely by reason of its forward tangential motion. That is +the answer.</p> + +<p>When writers who understand the subject talk about the +centripetal and centrifugal forces being different names for the +same force, and about equal action and reaction, and employ other +confusing expressions, just remember that all they really mean is +to express the universal relation between force and resistance. The +expression "centrifugal force" is itself so misleading, that it +becomes especially important that the real nature of this so-called +force, or the sense in which the term "force" is used in this +expression, should be fully explained.[1] This force is now seen to +be merely the tendency of a revolving body to move in a straight +line, and the resistance which it opposes to being drawn aside from +that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see.</p> + +<p>[Footnote 1: I was led to study this subject in looking to see +what had become of my first permanent investment, a small venture, +made about thirty-five years ago, in the "Sawyer and Gwynne static +pressure engine." This was the high-sounding name of the Keely +motor of that day, an imposition made possible by the confused +ideas prevalent on this very subject of centrifugal force.]</p> + +<p>FIRST.--I have called your attention to the fact that the +direction in which the revolving body is deflected from the +tangential line of motion is toward the center, on the radial line, +which forms a right angle with the tangent on which the body is +moving. The first question that presents itself is this: What is +the measure or amount of this deflection? The answer is, this +measure or amount is the versed sine of the angle through which the +body moves.</p> + +<p>Now, I suspect that some of you--some of those whom I am +directly addressing--may not know what the versed sine of an angle +is; so I must tell you. We will refer again to Fig. 1. In this +figure, O A is one radius of the circle in which the body A is +revolving. O C is another radius of this circle. These two radii +include between them the angle A O C. This angle is subtended by +the arc A C. If from the point O we let fall the line C E +perpendicular to the radius O A, this line will divide the radius O +A into two parts, O E and E A. Now we have the three interior +lines, or the three lines within the circle, which are fundamental +in trigonometry. C E is the sine, O E is the cosine, and E A is the +versed sine of the angle A O C. Respecting these three lines there +are many things to be observed. I will call your attention to the +following only:</p> + +<p><i>First</i>.--Their length is always less than the radius. The +radius is expressed by 1, or unity. So, these lines being less than +unity, their length is always expressed by decimals, which mean +equal to such a proportion of the radius.</p> + +<p><i>Second</i>.--The cosine and the versed sine are together +equal to the radius, so that the versed sine is always 1, less the +cosine.</p> + +<p><i>Third</i>.--If I diminish the angle A O C, by moving the +radius O C toward O A, the sine C E diminishes rapidly, and the +versed sine E A also diminishes, but more slowly, while the cosine +O E increases. This you will see represented in the smaller angles +shown in Fig. 2. If, finally, I make O C to coincide with O A, the +angle is obliterated, the sine and the versed sine have both +disappeared, and the cosine has become the radius.</p> + +<p><i>Fourth</i>.--If, on the contrary, I enlarge the angle A O C +by moving the radius O C toward O B, then the sine and the versed +sine both increase, and the cosine diminishes; and if, finally, I +make O C coincide with O B, then the cosine has disappeared, the +sine has become the radius O B, and the versed sine has become the +radius O A, thus forming the two sides inclosing the right angle A +O B. The study of this explanation will make you familiar with +these important lines. The sine and the cosine I shall have +occasion to employ in the latter part of my lecture. Now you know +what the versed sine of an angle is, and are able to observe in +Fig. 1 that the versed sine A E, of the angle A O C, represents in +a general way the distance that the body A will be deflected from +the tangent A D toward the center O while describing the arc A +C.</p> + +<p>The same law of deflection is shown, in smaller angles, in Fig. +2. In this figure, also, you observe in each of the angles A O B +and A O C that the deflection, from the tangential direction toward +the center, of a body moving in the arc A C is represented by the +versed sine of the angle. The tangent to the arc at A, from which +this deflection is measured, is omitted in this figure to avoid +confusion. It is shown sufficiently in Fig. 1. The angles in Fig. 2 +are still pretty large angles, being 12° and 24° +respectively. These large angles are used for convenience of +illustration; but it should be explained that this law does not +really hold in them, as is evident, because the arc is longer than +the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent +and arc coincide, and approximately so for exceedingly small +angles.</p> + +<p class="ctr"><img src="./illustrations/4a.png" alt="Fig. 2"></p> + +<p class="ctr">Fig. 2</p> + +<p>In reality, however, we have only to do with the case in which +the arc and the tangent do coincide, and in which the law that the +deflection is <i>equal to</i> the versed sine of the angle is +absolutely true. Here, in observing this most familiar thing, we +are, at a single step, taken to that which is utterly beyond our +comprehension. The angles we have to consider disappear, not only +from our sight, but even from our conception. As in every other +case when we push a physical investigation to its limit, so here +also, we find our power of thought transcended, and ourselves in +the presence of the infinite.</p> + +<p>We can discuss very small angles. We talk familiarly about the +angle which is subtended by 1" of arc. On Fig. 2, a short line is +drawn near to the radius O A'. The distance between O A' and this +short line is 1° of the arc A' B'. If we divide this distance +by 3,600, we get 1" of arc. The upper line of the Table of versed +sines given below is the versed sine of 1" of arc. It takes +1,296,000 of these angles to fill a circular space. These are a +great many angles, but they do not make a circle. They make a +polygon. If the radius of the circumscribed circle of this polygon +is 1,296,000 feet, which is nearly 213 geographical miles, each one +of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon +would be one-sixtieth of a geographical mile, or 101.46 feet. On +the orbit of the moon, at its mean distance from the earth, each of +these straight sides would be about 6,000 feet long.</p> + +<p>The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never +can reach the circle. When you swing a sling around your head, and +feel the uniform stress exerted on your hand through the cord, you +are made aware of an action which is entirely beyond the grasp of +our minds and the reach of our analysis.</p> + +<p>So always in practical operation that law is absolutely true +which we observe to be approximated to more and more nearly as we +consider smaller and smaller angles, that the versed sine of the +angle is the measure of its deflection from the straight line of +motion, or the measure of its fall toward the center, which takes +place at every point in the motion of a revolving body.</p> + +<p>Then, assuming the absolute truth of this law of deflection, we +find ourselves able to explain all the phenomena of centrifugal +force, and to compute its amount correctly in all cases.</p> + +<p>We have now advanced two steps. We have learned <i>the +direction</i> and <i>the measure</i> of the deflection, which a +revolving body continually suffers, and its resistance to which is +termed centrifugal force. The direction is toward the center, and +the measure is the versed sine of the angle.</p> + +<p>SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that +the amount of centrifugal force exerted by a revolving body varies +in four ways.</p> + +<p><i>First</i>.--Directly as the weight of the body.</p> + +<p><i>Second</i>.--In a given circle of revolution, as the square +of the speed or of the number of revolutions per minute; which two +expressions in this case mean the same thing.</p> + +<p><i>Third</i>.--With a given number of revolutions per minute, or +a given angular velocity[1] <i>directly</i> as the radius of the +circle; and</p> + +<p><i>Fourth</i>.--With a given actual velocity, or speed in feet +per minute, <i>inversely</i> as the radius of the circle.</p> + +<p>[Footnote 1: A revolving body is said to have the same angular +velocity, when it sweeps through equal angles in equal times. Its +actual velocity varies directly as the radius of the circle in +which it is revolving.]</p> + +<p>Of course there is a reason for these laws. You are not to learn +them by rote, or to accept them on any authority. You are taught +not to accept any rule or formula on authority, but to demand the +reason for it--to give yourselves no rest until you know the why +and wherefore, and comprehend these fully. This is education, not +cramming the mind with mere facts and rules to be memorized, but +drawing out the mental powers into activity, strengthening them by +use and exercise, and forming the habit, and at the same time +developing the power, of penetrating to the reason of things.</p> + +<p>In this way only, you will be able to meet the requirement of a +great educator, who said: "I do not care to be told what a young +man knows, but what he can <i>do</i>." I wish here to add my grain +to the weight of instruction which you receive, line upon line, +precept on precept, on this subject.</p> + +<p>The reason for these laws of centrifugal force is an extremely +simple one. The first law, that this force varies directly as the +weight of the body, is of course obvious. We need not refer to this +law any further. The second, third, and fourth laws merely express +the relative rates at which a revolving body is deflected from the +tangential direction of motion, in each of the three cases +described, and which cases embrace all possible conditions.</p> + +<p>These three rates of deflection are exhibited in Fig. 2. An +examination of this figure will give you a clear understanding of +them. Let us first suppose a body to be revolving about the point, +O, as a center, in a circle of which A B C is an arc, and with a +velocity which will carry it from A to B in one second of time. +Then in this time the body is deflected from the tangential +direction a distance equal to A D, the versed sine of the angle A O +B. Now let us suppose the velocity of this body to be doubled in +the same circle. In one second of time it moves from A to C, and is +deflected from the tangential direction of motion a distance equal +to A E, the versed sine of the angle, A O C. But A E is four times +A D. Here we see in a given circle of revolution the deflection +varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded.</p> + +<p>The following table will show, by comparison of the versed sines +of very small angles, the deflection in a given circle varying as +the square of the speed, when we penetrate to them, so nearly that +the error is not disclosed at the fifteenth place of decimals.</p> + +<pre> + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 +</pre> + +<p>You observe the deflection for 10" of arc is 100 times as great, +and for 100" of arc is 10,000 times as great as it is for 1" of +arc. So far as is shown by the 15th place of decimals, the versed +sine varies as the square of the angle; or, in a given circle, the +deflection, and so the centrifugal force, of a revolving body +varies as the square of the speed.</p> + +<p>The reason for the third law is equally apparent on inspection +of Fig. 2. It is obvious, that in the case of bodies making the +same number of revolutions in different circles, the deflection +must vary directly as the diameter of the circle, because for any +given angle the versed sine varies directly as the radius. Thus +radius O A' is twice radius O A, and so the versed sine of the arc +A' B' is twice the versed sine of the arc A B. Here, while the +angular velocity is the same, the actual velocity is doubled by +increase in the diameter of the circle, and so the deflection is +doubled. This exhibits the general law, that with a given angular +velocity the centrifugal force varies directly as the radius or +diameter of the circle.</p> + +<p>We come now to the reason for the fourth law, that, with a given +actual velocity, the centrifugal force varies <i>inversely</i> as +the diameter of the circle. If any of you ever revolved a weight at +the end of a cord with some velocity, and let the cord wind up, +suppose around your hand, without doing anything to accelerate the +motion, then, while the circle of revolution was growing smaller, +the actual velocity continuing nearly uniform, you have felt the +continually increasing stress, and have observed the increasing +angular velocity, the two obviously increasing in the same ratio. +That is the operation or action which the fourth law of centrifugal +force expresses. An examination of this same figure (Fig. 2) will +show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. +If we take the velocity A' B', double the velocity A B, and +transfer it to the smaller circle, we have the velocity A C. But +the deflection has been increasing as we have reduced the circle, +and now with one half the radius it is twice as great. It has +increased in the same ratio in which the angular velocity has +increased. Thus we see the simple and necessary nature of these +laws. They merely express the different rates of deflection of a +revolving body in these different cases.</p> + +<p>THIRD.--We have a coefficient of centrifugal force, by which we +are enabled to compute the amount of this resistance of a revolving +body to deflection from a direct line of motion in all cases. This +is that coefficient. The centrifugal force of a body making +<i>one</i> revolution per minute, in a circle of <i>one</i> foot +radius, is 0.000341 of the weight of the body.</p> + +<p>According to the above laws, we have only to multiply this +coefficient by the square of the number of revolutions made by the +body per minute, and this product by the radius of the circle in +feet, or in decimals of a foot, and we have the centrifugal force, +in terms of the weight of the body. Multiplying this by the weight +of the body in pounds, we have the centrifugal force in pounds.</p> + +<p>Of course you want to know how this coefficient has been found +out, and how you can be sure it is correct. I will tell you a very +simple way. There are also mathematical methods of ascertaining +this coefficient, which your professors, if you ask them, will let +you dig out for yourselves. The way I am going to tell you I found +out for myself, and that, I assure you, is the only way to learn +anything, so that it will stick; and the more trouble the search +gives you, the darker the way seems, and the greater the degree of +perseverance that is demanded, the more you will appreciate the +truth when you have found it, and the more complete and permanent +your possession of it will be.</p> + +<p>The explanation of this method may be a little more abstruse +than the explanations already given, but it is very simple and +elegant when you see it, and I fancy I can make it quite clear. I +shall have to preface it by the explanation of two simple laws. The +first of these is, that a body acted on by a constant force, so as +to have its motion uniformly accelerated, suppose in a straight +line, moves through distances which increase as the square of the +time that the accelerating force continues to be exerted.</p> + +<p>The necessary nature of this law, or rather the action of which +this law is the expression, is shown in Fig. 3.</p> + +<p class="ctr"><img src="./illustrations/4b.png" alt="Fig. 3"></p> + +<p class="ctr">Fig. 3</p> + +<p>Let the distances A B, B C, C D, and D E in this figure +represent four successive seconds of time. They may just as well be +conceived to represent any other equal units, however small. +Seconds are taken only for convenience. At the commencement of the +first second, let a body start from a state of rest at A, under the +action of a constant force, sufficient to move it in one second +through a distance of one foot. This distance also is taken only +for convenience. At the end of this second, the body will have +acquired a velocity of two feet per second. This is obvious +because, in order to move through one foot in this second, the body +must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. +Its motion increased uniformly. Therefore, at the termination of +the second its velocity must have reached two feet per second. Let +the triangle A B F represent this accelerated motion, and the +distance, of one foot, moved through during the first second, and +let the line B F represent the velocity of two feet per second, +acquired by the body at the end of it. Now let us imagine the +action of the accelerating force suddenly to cease, and the body to +move on merely with the velocity it has acquired. During the next +second it will move through two feet, as represented by the square +B F C I. But in fact, the action of the accelerating force does not +cease. This force continues to be exerted, and produces on the body +during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity +accelerated two additional feet per second, as represented by the +line I G. So in two seconds the body has moved through four feet. +We may follow the operation of this law as far as we choose. The +figure shows it during four seconds, or any other unit, of time, +and also for any unit of distance. Thus:</p> + +<pre> + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 +</pre> + +<p>So it is obvious that the distance moved through by a body whose +motion is uniformly accelerated increases as the square of the +time.</p> + +<p>But, you are asking, what has all this to do with a revolving +body? As soon as your minds can be started from a state of rest, +you will perceive that it has everything to do with a revolving +body. The centripetal force, which acts upon a revolving body to +draw it to the center, is a constant force, and under it the +revolving body must move or be deflected through distances which +increase as the squares of the times, just as any body must do when +acted on by a constant force. To prove that a revolving body obeys +this law, I have only to draw your attention to Fig. 2. Let the +equal arcs, A B and B C, in this figure represent now equal times, +as they will do in case of a body revolving in this circle with a +uniform velocity. The versed sines of the angles, A O B and A O C, +show that in the time, A C, the revolving body was deflected four +times as far from the tangent to the circle at A as it was in the +time, A B. So the deflection increased as the square of the time. +If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute +angles, absolutely so far as appears up to the fifteenth place of +decimals, as the square of the time.</p> + +<p>The standard from which all computations are made of the +distances passed through in given times by bodies whose motion is +uniformly accelerated, and from which the velocity acquired is +computed when the accelerating force is known, and the force is +found when the velocity acquired or the rate of acceleration is +known, is the velocity of a body falling to the earth. It has been +established by experiment, that in this latitude near the level of +the sea, a falling body in one second falls through a distance of +16.083 feet, and acquires a velocity of 32.166 feet per second; or, +rather, that it would do so if it did not meet the resistance of +the atmosphere. In the case of a falling body, its weight +furnishes, first, the inertia, or the resistance to motion, that +has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the +earth, or the force exerted to overcome its resistance. Here, as in +all possible cases, the force and the resistance are identical with +each other. The above is, therefore, found in this way to be the +rate at which the motion of any body will be accelerated when it is +acted on by a constant force equal to its weight, and encounters no +resistance.</p> + +<p>It follows that a revolving body, when moving uniformly in any +circle at a speed at which its deflection from a straight line of +motion is such that in one second this would amount to 16.083 feet, +requires the exertion of a centripetal force equal to its weight to +produce such deflection. The deflection varying as the square of +the time, in 0.01 of a second this deflection will be through a +distance of 0.0016083 of a foot.</p> + +<p>Now, at what speed must a body revolve, in a circle of one foot +radius, in order that in 0.01 of one second of time its deflection +from a tangential direction shall be 0.0016083 of a foot? This +decimal is the versed sine of the arc of 3°15', or of +3.25°. This angle is so small that the departure from the law +that the deflection is equal to the versed sine of the angle is too +slight to appear in our computation. Therefore, the arc of +3.25° is the arc of a circle of one foot radius through which a +body must revolve in 0.01 of a second of time, in order that the +centripetal force, and so the centrifugal force, shall be equal to +its weight. At this rate of revolution, in one second the body will +revolve through 325°, which is at the rate of 54.166 +revolutions per minute.</p> + +<p>Now there remains only one question more to be answered. If at +54.166 revolutions per minute the centrifugal force of a body is +equal to its weight, what will its centrifugal force be at one +revolution per minute in the same circle?</p> + +<p>To answer this question we have to employ the other extremely +simple law, which I said I must explain to you. It is this: The +acceleration and the force vary in a constant ratio with each +other. Thus, let force 1 produce acceleration 1, then force 1 +applied again will produce acceleration 1 again, or, in other +words, force 2 will produce acceleration 2, and so on. This being +so, and the amount of the deflection varying as the squares of the +speeds in the two cases, the centrifugal force of a body making one +revolution per minute in a circle of</p> + +<pre> + 1² + one foot radius will be ---------- = 0.000341 + 54.166² +</pre> + +<p>--the coefficient of centrifugal force.</p> + +<p>There is another mode of making this computation, which is +rather neater and more expeditious than the above. A body making +one revolution per minute in a circle of one foot radius will in +one second revolve through an arc of 6°. The versed sine of +this arc of 6° is 0.0054781046 of a foot. This is, therefore, +the distance through which a body revolving at this rate will be +deflected in one second. If it were acted on by a force equal to +its weight, it would be deflected through the distance of 16.083 +feet in the same time. What is the deflecting force actually +exerted upon it? Of</p> + +<pre> + 0.0054781046 +course, it is ------------. + 16.083 +</pre> + +<p>This division gives 0.000341 of its weight as such deflecting +force, the same as before.</p> + +<p>In taking the versed sine of 6°, a minute error is involved, +though not one large enough to change the last figure in the above +quotient. The law of uniform acceleration does not quite hold when +we come to an angle so large as 6°. If closer accuracy is +demanded, we can attain it, by taking the versed sine for 1°, +and multiplying this by 6². This gives as a product +0.0054829728, which is a little larger than the versed sine of +6°.</p> + +<p>I hope I have now kept my promise, and made it clear how the +coefficient of centrifugal force may be found in this simple +way.</p> + +<p>We have now learned several things about centrifugal force. Let +me recapitulate. We have learned:</p> + +<p>1st. The real nature of centrifugal force. That in the dynamical +sense of the term force, this is not a force at all: that it is not +capable of producing motion, that the force which is really exerted +on a revolving body is the centripetal force, and what we are +taught to call centrifugal force is nothing but the resistance +which a revolving body opposes to this force, precisely like any +other resistance.</p> + +<p>2d. The direction of the deflection, to which the centrifugal +force is the resistance, which is straight to the center.</p> + +<p>3d. The measure of this deflection; the versed sine of the +angle.</p> + +<p>4th. The reason of the laws of centrifugal force; that these +laws merely express the relative amount of the deflection, and so +the amount of the force required to produce the deflection, and of +the resistance of the revolving body to it, in all different +cases.</p> + +<p>5th. That the deflection of a revolving body presents a case +analogous to that of uniformly accelerated motion, under the action +of a constant force, similar to that which is presented by falling +bodies;[1] and finally,</p> + +<p>6th. How to find the coefficient, by which the amount of +centrifugal force exerted in any case may be computed.</p> + +<p>[Footnote 1: A body revolving with a uniform velocity in a +horizontal plane would present the only case of uniformly +accelerated motion that is possible to be realized under actual +conditions.]</p> + +<p>I now pass to some other features.</p> + +<p><i>First</i>.--You will observe that, relatively to the center, +a revolving body, at any point in its revolution, is at rest. That +is, it has no motion, either from or toward the center, except that +which is produced by the action of the centripetal force. It has, +therefore, this identity also with a falling body, that it starts +from a state of rest. This brings us to a far more comprehensive +definition of centrifugal force. This is the resistance which a +body opposes to being put in motion, at any velocity acquired in +any time, from a state of rest. Thus centrifugal force reveals to +us the measure of the inertia of matter. This inertia may be +demonstrated and exhibited by means of apparatus constructed on +this principle quite as accurately as it can be in any other +way.</p> + +<p><i>Second</i>.--You will also observe the fact, that motion must +be imparted to a body gradually. As distance, <i>through</i> which +force can act, is necessary to the impartation of velocity, so also +time, <i>during</i> which force can act, is necessary to the same +result. We do not know how motion from a state of rest begins, any +more than we know how a polygon becomes a circle. But we do know +that infinite force cannot impart absolutely instantaneous motion +to even the smallest body, or to a body capable of opposing the +least resistance. Time being an essential element or factor in the +impartation of velocity, if this factor be omitted, the least +resistance becomes infinite.</p> + +<p>We have a practical illustration of this truth in the explosion +of nitro-glycerine. If a small portion of this compound be exploded +on the surface of a granite bowlder, in the open air, the bowlder +will be rent into fragments. The explanation of this phenomenon +common among the laborers who are the most numerous witnesses of +it, which you have doubtless often heard, and which is accepted by +ignorant minds without further thought, is that the action of +nitro-glycerine is downward. We know that such an idea is +absurd.</p> + +<p>The explosive force must be exerted in all directions equally. +The real explanation is, that the explosive action of +nitro-glycerine is so nearly instantaneous, that the resistance of +the atmosphere is very nearly equal to that of the rock; at any +rate, is sufficient to cause the rock to be broken up. The rock +yields to the force very nearly as readily as the atmosphere +does.</p> + +<p><i>Third</i>. An interesting solution is presented here of what +is to many an astronomical puzzle. When I was younger than I am +now, I was greatly troubled to understand how it could be that if +the moon was always falling to the earth, as the astronomers +assured us it was, it should never reach it, nor have its falling +velocity accelerated. In popular treatises on astronomy, such for +example as that of Professor Newcomb, this is explained by a +diagram in which the tangential line is carried out as in Fig. 1, +and by showing that in falling from the point A to the earth as a +center, through distances increasing as the square of the time, the +moon, having the tangential velocity that it has, could never get +nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this +long tangential line has nothing to do with the motion of the moon, +and while we are compelled to assent to the demonstration, we want +something better. To my mind the better and more satisfactory +explanation is found in the fact that the moon is forever +commencing to fall, and is continually beginning to fall in a new +direction. A revolving body, as we have seen, never gets past that +point, which is entirely beyond our sight and our comprehension, of +beginning to fall, before the direction of its fall is changed. So, +under the attraction of the earth, the moon is forever leaving a +new tangential direction of motion at the same rate, without +acceleration.</p> + +<p>(<i>To be continued</i>.)</p> + +<hr> +<p><a name="6"></a></p> + +<h2>COMPRESSED AIR POWER SCHEMES.</h2> + +<h3>By J. STURGEON, Engineer of the Birmingham Compressed Air Power +Company.</h3> + +<p>In the article on "Gas, Air, and Water Power" in the +<i>Journal</i> for Dec. 8 last, you state that you await with some +curiosity my reply to certain points in reference to the compressed +air power schemes alluded to in that article. I now, therefore, +take the liberty of submitting to you the arguments on my side of +the question (which are substantially the same as those I am +submitting to Mr. Hewson, the Borough Engineer of Leeds). The +details and estimates for the Leeds scheme are not yet in a forward +enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system +in other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters +of detail. We have, however, recently succeeded in obtaining a +suitable place, and making arrangements for railway siding, water +supply, etc.; and we hope to be in a position to start early in the +present year.</p> + +<p>I inclose (1) a tabulated summary of the estimates for +Birmingham divided into stages of 3,000 gross indicated horse power +at a time; (2) a statement showing the cost to consumers in terms +of indicated horse power and in different modes, more or less +economical, of applying the air power in the consumers' engines; +(3) a tracing showing the method of laying the mains; (4) a tracing +showing the method of collecting the meter records at the central +station, by means of electric apparatus, and ascertaining the exact +amount of leakage. A short description of the two latter would be +as well.</p> + +<p>TABLE I.--<i>Showing the Progressive Development of the +Compressed Air System in stages of 3000 Indicated Horse Power +(gross) at a Time, and the Profits at each Stage</i></p> + +<pre> +_____________________________________________________________________________ +<br> +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- +<br> +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- +<br> +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| £12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | £25,595 | £25,595 | £25,595 | £25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | £82,455 | £124,714 | £167,094 | £209,455 | £251,795 | +----------------------------------------------------------------------------- +<br> +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| £6,405 | £7,855 | £9,305 | £10,955 | £12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | £12,080 | £18,508 | £24,944 | £31,589 | £38,096 | +----------------------------------------------------------------------------- +<br> +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- +</pre> + +<p>TABLE II.--<i>Cost of Air Power in Terms of Indicated Horse +Power</i>.</p> + +<p>Abbreviated column headings:</p> + +<p>Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. +H.P. per Hour.</p> + +<p>Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet.</p> + +<p>Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach +26 per Cent.</p> + +<p>Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic +Feet.</p> + +<p>Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach +26 per Cent.</p> + +<p>Abbreviated row headings:</p> + +<p>CASE 1.--Where air at 45 lbs. pressure is re-heated to 320° +Fahr., and expanded to atmospheric pressure.</p> + +<p>CASE 2.--Where air at 45 lbs. pressure is heated by boiling +water to 212° Fahr., and expanded to atmospheric pressure.</p> + +<p>CASE 3.--Where air is used expansively without re-heating, +whereby intensely cold air is exhausted, and may be used for ice +making, &c.</p> + +<p>CASE 4.--Where air is heated to 212° Fahr., and the terminal +pressure is 11.3 lbs. above that of the atmosphere</p> + +<p>CASE 5.--Where the air is used without heating, and cut off at +one-third of the stroke, as in ordinary slide-valve engines</p> + +<p>CASE 6.--Where the air is used without re-heating and without +expansion.</p> + +<pre> + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | £ s. d. | £ s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 0½| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 5½ | 9 10 5½| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 5½ | 9 1 10½| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ +</pre> + +<p>The great thing to guard against is leakage. If the pipes were +simply buried in the ground, it would be almost impossible to trace +leakage, or even to know of its existence. The income of the +company might be wasting away, and the loss never suspected until +the quarterly returns from the meters were obtained from the +inspectors. Only then would it be discovered that there must be a +great leak (or it might be several leaks) somewhere. But how would +it be possible to trace them among 20 or 30 miles of buried pipes? +We cannot break up the public streets. The very existence of the +concern depends upon (1) the <i>daily</i> checking of the meter +returns, and comparison with the output from the air compressors, +so as to ascertain the amount of leakage; (2) facility for tracing +the locality of a leak; and (3) easy access to the mains with the +minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the +pipes are laid in concrete troughs, near the surface of the road, +with removable concrete covers strong enough to stand any overhead +traffic. At intervals there are junctions for service connections, +with street boxes and covers serving as inspection chambers. These +chambers are also provided over the ball-valves, which serve as +stop-valves in case of necessity, and are so arranged that in case +of a serious breach in the portion of main between any two of them, +the rush of air to the breach will blow them up to the +corresponding seats and block off the broken portion of main. The +air space around the pipe in the concrete trough will convey for a +long distance the whistling noise of a leak; and the inspectors, by +listening at the inspection openings, will thus be enabled to +rapidly trace their way almost to the exact spot where there is an +escape. They have then only to remove the top surface of road metal +and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring +from the nearest street opening, the inspectors would know where to +break open the road to arrive at the probable locality of the leak. +A very slight leak can be heard a long way off by its peculiar +whistling sound.</p> + +<p class="ctr"><a href="./illustrations/6a.png"><img src= +"./illustrations/6a_th.jpg" alt="COMPRESSED AIR POWER"></a></p> + +<p class="ctr">COMPRESSED AIR POWER</p> + +<p>The next point is to obtain a daily report of the condition of +the mains and the amount of leakage. It would be impracticable to +employ an army of meter inspectors to take the records daily from +all the meters in the district. We therefore adopt the method of +electric signaling shown in the second drawing. In the engineer's +office, at the central station, is fixed the dial shown in Fig. 1. +Each consumer's meter is fitted with the contact-making apparatus +shown in Pig. 4, and in an enlarged form in Figs. 5 and 6, by which +a current is sent round the electro-magnet, D (Fig. 1), attracting +the armature, and drawing the disk forward sufficiently for the +roller at I to pass over the center of one of the pins, and so drop +in between that and the next pin, thus completing the motion, and +holding the disk steadily opposite the figure. This action takes +place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose +one meter should be moving very slowly, and so retaining contact +for some time, while other meters were working rapidly; the +armature at D would then be held up to the magnet by the prolonged +contact maintained by the slow moving meter, and so prevent the +quick working meters from actuating it; and they would therefore +pass the contact points without recording. A meter might also stop +dead at the point of contact on shutting off the air, and so hold +up the armature; thus preventing others from acting. To obviate +this, we apply the disengaging apparatus shown at L (Fig. 4). The +contact maker works on the center, m, having an armature on its +opposite end. On contact being made, at the same time that the +magnet, D, is operated, the one at L is also operated, attracting +the armature, and throwing over the end of the contact maker, +l¹, on to the non-conducting side of the pin on the disk. Thus +the whole movement is rendered practically instantaneous, and the +magnet at D is set at liberty for the next operation. A resistance +can be interposed at L, if necessary, to regulate the period of the +operation. The whole of the meters work the common dial shown in +Fig. 1, on which the gross results only are recorded; and this is +all we want to know in this way. The action is so rapid, owing to +the use of the magnetic disengaging gear, that the chances of two +or more meters making contact at the same moment are rendered +extremely small. Should such a thing happen, it would not matter, +as it is only approximate results that we require in this case; and +the error, if any, would add to the apparent amount of leakage, and +so be on the right side. Of course, the record of each consumer's +meter would be taken by the inspector at the end of every quarter, +in order to make out the bill; and the totals thus obtained would +be checked by the gross results indicated by the main dial. In this +way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected +to an extremely accurate measurement. At the end of the working +day, the engineer has merely to take down from the dial in his +office the total record of air measured to the consumers, also the +output of air from the compressors, which he ascertains by means of +a continuous counter on the engines, and the difference between the +two will represent the loss. If the loss is trifling, he will pass +it over; if serious, he will send out his inspectors to trace it. +Thus there could be no long continued leakage, misuse, or robbery +of the air, without the company becoming aware of the fact, and so +being enabled to take measures to stop or prevent it. The foregoing +are absolutely essential adjuncts to any scheme of public motive +power supply by compressed air, without which we should be working +in the dark, and could never be sure whether the company were +losing or making money. With them, we know where we are and what we +are doing.</p> + +<p>Referring to the estimates given in Table I., I may explain that +the item of repairs and renewals covers 10 per cent. on boilers and +gas producers, 5 per cent. on engines, 5 per cent. on buildings, +and 5 per cent. on mains. Considering that the estimates include +ample fitting shops, with the best and most suitable tools, and +that the wages list includes a staff of men whose chief work would +be to attend to repairs, etc., I think the above allowances ample. +Each item also includes 5 per cent. for contingencies.</p> + +<p>I have commenced by giving all the preceding detail, in order to +show the groundwork on which I base the estimate of the cost of +compressed air power to consumers, in terms of indicated horse +power per annum, as given in Table II. I may say that, in +estimating the engine power and coal consumption, I have not, as in +the original report, made purely theoretical calculations, but have +taken diagrams from engines in actual use (although of somewhat +smaller size than those intended to be employed), and have worked +out the results therefrom. It will, I hope, be seen that, with all +the safeguards we have provided, we may fairly reckon upon having +for sale the stated quantity of air produced by means of the plant, +as estimated, and at the specified annual cost; and that therefore +the statement of cost per indicated horse power per annum may be +fairly relied upon. Thus the cost of compressed air to the +consumer, based upon an <i>average</i> charge of 5d. per 1,000 +cubic feet, will vary from £6 14s. per indicated horse power +per annum to £18 13s. 3d., according to circumstances and +mode of application.</p> + +<p>A compressed air motor is an exceedingly simple machine--much +simpler than an ordinary steam engine. But the air may also be used +in an ordinary steam engine; and in this case it can be much +simplified in many details. Very little packing is needed, as there +is no nuisance from gland leakage; the friction is therefore very +slight. Pistons and glands are packed with soapstone, or other +self-lubricating packing; and no oil is required except for +bearings, etc. The company will undertake the periodical inspection +and overhauling of engines supplied with their power, all which is +included in the estimates. The total cost to consumers, with air at +an average of 5d. per 1,000 cubic feet, may therefore be fairly +taken as follows:</p> + +<pre> + Min. Max. + Cost of air used £6 14 0½ £18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 12½ per cent. on + £10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + £8 19 0½ £20 18 3 +</pre> + +<p>The maximum case would apply only to direct acting engines, such +as Tangye pumps, air power hammers, etc., where the air is full on +till the end of the stroke, and where there is no expansion. The +minimum given is at the average rate of 5d. per 1,000 cubic feet; +but as there will be rates below this, according to a sliding +scale, we may fairly take it that the lowest charge will fall +considerably below £6 per indicated horse power per +annum.--<i>Journal of Gas Lighting</i>.</p> + +<hr> +<p><a name="7"></a></p> + +<h2>THE BERTHON COLLAPSIBLE CANOE.</h2> + +<p>An endeavor has often been made to construct a canoe that a +person can easily carry overland and put into the water without +aid, and convert into a sailboat. The system that we now call +attention to is very well contrived, very light, easily taken +apart, and for some years past has met with much favor.</p> + +<p class="ctr"><img src="./illustrations/6b.png" alt= +"FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT."></p> + +<p class="ctr">FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.</p> + +<p>Mr. Berthon's canoes are made of impervious oil-skin. Form is +given them by two stiff wooden gunwales which are held in position +by struts that can be easily put in and taken out. The model shown +in the figure is covered with oiled canvas, and is provided with a +double paddle and a small sail. Fig. 2 represents it collapsed and +being carried overland.</p> + +<p class="ctr"><img src="./illustrations/6c.png" alt= +"FIG. 2.--THE SAME BEING CARRIED OVERLAND."></p> + +<p class="ctr">FIG. 2.--THE SAME BEING CARRIED OVERLAND.</p> + +<p>Mr. Berthon is manufacturing a still simpler style, which is +provided with two oars, as in an ordinary canoe. This model, which +is much used in England by fishermen and hunters, has for several +years past been employed in the French navy, in connection with +movable defenses. At present, every torpedo boat carries one or two +of these canoes, each composed of two independent halves that may +be put into the water separately or be joined together by an iron +rod.</p> + +<p>These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure +without danger.[1]--<i>La Nature</i>.</p> + +<p>[Footnote 1: For detailed description see SUPPLEMENT, No. +84.]</p> + +<hr> +<p><a name="8"></a></p> + +<h2>THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN +STEAM RAILROAD.</h2> + +<p>There was great excitement in Nürnberg on the 7th of +December, 1835, on which day the first German railroad was opened. +The great square on which the buildings of the Nürnberg and +Furth "Ludwig's Road" stood, the neighboring streets, and, in fact, +the whole road between the two cities, was filled with a crowd of +people who flocked from far and near to see the wonderful +spectacle. For the first time, a railroad train filled with +passengers was to be drawn from Nürnberg to Furth by the +invisible power of the steam horse. At eight o'clock in the +morning, the civil and military authorities, etc., who took part in +the celebration were assembled on the square, and the gayly +decorated train started off to an accompaniment of music, +cannonading, cheering, etc. Everything passed off without an +accident; the work was a success. The engraving in the lower +right-hand corner represents the engine and cars of this road.</p> + +<p>It will be plainly seen that such a revolution could not be +accomplished easily, and that much sacrifice and energy were +required of the leaders in the enterprise, prominent among whom was +the merchant Johannes Scharrer, who is known as the founder of the +"Ludwig's Road."</p> + +<p>One would naturally suppose that such an undertaking would have +met with encouragement from the Bavarian Government, but this was +not the case. The starters of the enterprise met with opposition on +every side; much was written against it, and many comic pictures +were drawn showing accidents which would probably occur on the much +talked of road. Two of these pictures are shown in the accompanying +large engraving, taken from the <i>Illustrirte Zeitung</i>. As +shown in the center picture, right hand, it was expected by the +railway opponents that trains running on tracks at right angles +must necessarily come in collision. If anything happened to the +engine, the passengers would have to get out and push the cars, as +shown at the left.</p> + +<p class="ctr"><a href="./illustrations/7a.png"><img src= +"./illustrations/7a_th.jpg" alt=""></a></p> + +<p class="ctr">JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF +THE OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--<br> +AT NURNBERG</p> + +<p>Much difficulty was experienced in finding an engineer capable +of attending to the construction of the road; and at first it was +thought that it would be best to engage an Englishman, but finally +Engineer Denis, of Munich, was appointed. He had spent much time in +England and America studying the roads there, and carried on this +work to the entire satisfaction of the company.</p> + +<p>All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to +be given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first +prize in the competitive trials at Rainhill in 1829, delivered an +engine of ten horse power, which is still known in Nürnberg as +"Der Englander."</p> + +<p>Fifty years have passed, and, as Johannes Scharrer predicted, +the Ludwig's Road has become a permanent institution, though it now +forms only a very small part of the network of railroads which +covers every portion of Germany. What changes have been made in +railroads during these fifty years! Compare the present locomotives +with the one made by Cugnot in 1770, shown in the upper left-hand +cut, and with the work of the pioneer Geo. Stephenson, who in 1825 +constructed the first passenger railroad in England, and who +established a locomotive factory in Newcastle in 1824. Geo. +Stephenson was to his time what Mr. Borsig, whose great works at +Moabit now turn out from 200 to 250 locomotives a year, is to our +time.</p> + +<p>Truly, in this time there can be no better occasion for a +celebration of this kind than the fiftieth anniversary of the +opening of the first German railroad, which has lately been +celebrated by Nürnberg and Furth.</p> + +<p>The lower left-hand view shows the locomotive De Witt Clinton, +the third one built in the United States for actual service, and +the coaches. The engine was built at the West Point Foundry, and +was successfully tested on the Mohawk and Hudson Railroad between +Albany and Schenectady on Aug. 9, 1831.</p> + +<hr> +<p><a name="9"></a></p> + +<h2>IMPROVED COAL ELEVATOR.</h2> + +<p>An illustration of a new coal elevator is herewith presented, +which presents advantages over any incline yet used, so that a +short description may be deemed interesting to those engaged in the +coaling and unloading of vessels. The pen sketch shows at a glance +the arrangement and space the elevator occupies, taking less ground +to do the same amount of work than any other mode heretofore +adopted, and the first cost of erecting is about the same as any +other.</p> + +<p>When the expense of repairing damages caused by the ravages of +winter is taken into consideration, and no floats to pump out or +tracks to wash away, the advantages should be in favor of a +substantial structure.</p> + +<p>The capacity of this hoist is to elevate 80,000 bushels in ten +hours, at less than one-half cent per bushel, and put coal in +elevator, yard, or shipping bins.</p> + +<p class="ctr"><a href="./illustrations/8a.png"><img src= +"./illustrations/8a_th.jpg" alt="IMPROVED COAL ELEVATOR."></a></p> + +<p class="ctr">IMPROVED COAL ELEVATOR.</p> + +<p>The endless wire rope takes the cars out and returns them, +dispensing with the use of train riders.</p> + +<p>A floating elevator can distribute coal at any hatch on steam +vessels, as the coal has to be handled but once; the hoist +depositing an empty car where there is a loaded one in boat or +barge, requiring no swing of the vessel.</p> + +<p>Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor +and builder, and has them in use in the U.S. engineering +service.--<i>Coal Trade Journal</i>.</p> + +<hr> +<p><a name="10"></a></p> + +<h2>STEEL-MAKING LADLES.</h2> + +<p>The practice of carrying melted cast iron direct from the blast +furnace to the Siemens hearth or the Bessemer converter saves both +money and time. It has rendered necessary the construction of +special plant in the form of ladles of dimensions hitherto quite +unknown. Messrs. Stevenson & Co., of Preston, make the +construction of these ladles a specialty, and by their courtesy, +says <i>The Engineer</i>, we are enabled to illustrate four +different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel +foundry work, and one of these for the Siemens-Martin process is +illustrated by Fig. 1. These ladles are made in sizes to take from +five to fifteen ton charges, or larger if required, and are mounted +on a very strong carriage with a backward and forward traversing +motion, and tipping gear for the ladle. The ladles are butt +jointed, with internal cover strips, and have a very strong band +shrunk on hot about half way in the depth of the ladle. This forms +an abutment for supporting the ladle in the gudgeon band, being +secured to this last by latch bolts and cotters. The gearing is +made of cast steel, and there is a platform at one end for the +person operating the carriage or tipping the ladle. Stopper gear +and a handle are fitted to the ladles to regulate the flow of the +molten steel from the nozzle at the bottom.</p> + +<p class="ctr"><a href="./illustrations/8b.png"><img src= +"./illustrations/8b_th.jpg" alt= +"LADLES FOR CARRYING MOLTEN IRON AND STEEL."></a></p> + +<p class="ctr">LADLES FOR CARRYING MOLTEN IRON AND STEEL.</p> + +<p>Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. +It requires no description. Fig. 3 shows a tremendous ladle +constructed for the North-Eastern Steel Company, for carrying +molten metal from the blast furnace to the converter. It holds ten +tons with ease. It is an exceptionally strong structure. The +carriage frame is constructed throughout of 1 in. wrought-iron +plated, and is made to suit the ordinary 4 ft. 8½ in. +railway gauge. The axle boxes are cast iron, fitted with gun-metal +steps. The wheels are made of forged iron, with steel tires and +axles. The carriage is provided with strong oak buffers, planks, +and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of ½ in. +wrought-iron plates, butt jointed, and double riveted butt straps. +The trunnions and flange couplings are of cast steel. The tipping +gear, clearly shown in the engraving, consists of a worm and wheel, +both of steel, which can be fixed on either side of the ladle as +may be desired. From this it will be seen that Messrs. Stevenson +& Co. have made a thoroughly strong structure in every respect, +and one, therefore, that will commend itself to most steel makers. +We understand that these carriages are made in various designs and +sizes to meet special requirements. Thus, Fig. 4 shows one of +different design, made for a steel works in the North. This is also +a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great +care and honesty of purpose is required in making these structures. +A breakdown might any moment pour ten tons of molten metal on the +ground, with the most horrible results.</p> + +<hr> +<p><a name="13"></a></p> + +<h2>APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON +THE SURFACE OF CONDUCTORS.</h2> + +<p>Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple +and ingenious apparatus which permits of demonstrating that +electricity develops only on the surface of conductors. It consists +(see figure) essentially of a yellow-metal disk, M, fixed to an +insulating support, F, and carrying a concentric disk of ebonite, +H. This latter receives a hollow and closed hemisphere, J, of +yellow metal, whose base has a smaller diameter than that of the +disk, H, and is perfectly insulated by the latter. Another +yellow-metal hemisphere, S, open below, is connected with an +insulating handle, G. The basal diameter of this second hemisphere +is such that when the latter is placed over J its edge rests upon +the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a +hollow, closed hemisphere that imprisons the hemisphere, J, which +is likewise hollow and closed, and perfectly insulated from the +former.</p> + +<p class="ctr"><img src="./illustrations/9a.png" alt=""></p> + +<p>The shell, S, is provided internally with a curved yellow-metal +spring, whose point of attachment is at B, and whose free extremity +is connected with an ebonite button, K, which projects from the +shell, S. By pressing this button, a contact may be established +between the external hemisphere (formed of the pieces, S and M), +and the internal one, J. As soon as the button is left to itself, +the spring again begins to bear against the interior surface of S, +and the two hemispheres are again insulated.</p> + +<p>The experiment is performed in this wise: The shell, S, is +removed. Then a disk of steatite affixed to an insulating handle is +rubbed for a few instants with a fox's "brush," and held near J +until a spark occurs. Then the apparatus is grasped by the support, +F, and an elder-pith ball suspended by a flaxen thread from a good +conducting support is brought near J. The ball will be quickly +repelled, and care must be taken that it does not come into contact +with J. After this the apparatus is placed upon a table, the shell, +S, is taken by its handle, G, and placed in the position shown in +the figure, and a momentary contact is established between the two +hemispheres by pressing the button, K. Then the shell, S, is +lifted, and the disk, M, is touched at the same time with the other +hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, +thus proving that all the electricity passed from J to S at the +moment of contact.--<i>La Lumiere Electrique</i>.</p> + +<hr> +<p><a name="14"></a></p> + +<h2>THE COLSON TELEPHONE.</h2> + +<p>This apparatus has recently been the object of some experiments +which resulted in its being finally adopted in the army. We think +that our readers will read a description of it with interest. Its +mode of construction is based upon a theoretic conception of the +lines of force, which its inventor explains as follows in his +Elementary Treatise on Electricity:</p> + +<p>"To every position of the disk of a magnetic telephone with +respect to the poles of the magnet there corresponds a certain +distribution of the lines of force, which latter shift themselves +when the disk is vibrating. If the bobbin be met by these lines in +motion, there will develop in its wire a difference of potential +that, according to Faraday's law, will be proportional to their +number. All things equal, then, a telephone transmitter will be so +much the more potent in proportion as the lines set in motion by +the vibrations of the disk and meeting the bobbin wire are greater +in number. In like manner, a receiver will be so much the more +potent in proportion as the lines of force, set in motion by +variations in the induced currents that are traversing the bobbin +and meeting the disk, are more numerous. It will consequently be +seen that, generally speaking, it is well to send as large a number +of lines of force as possible through the bobbin."</p> + +<p class="ctr"><img src="./illustrations/9b.png" alt= +"FIG. 1.--THE COLSON TELEPHONE."></p> + +<p class="ctr">FIG. 1.--THE COLSON TELEPHONE.</p> + +<p>In order to obtain such a result, the thin tin-plate disk has to +be placed between the two poles of the magnet. The pole that +carries the fine wire bobbin acts at one side and in the center of +the disk, while the other is expanded at the extremity and acts +upon the edge and the other side. This pole is separated from the +disk by a copper washer, and the disk is thus wholly immersed in +the magnetic field, and is traversed by the lines of force +radiatingly.</p> + +<p>This telephone is being constructed by Mr. De Branville, with +the greatest care, in the form of a transmitter (Fig. 2) and +receiver (Fig. 3). At A may be seen the magnet with its central +pole, P, and its eccentric one, P'. This latter traverses the +vibrating disk, M, through a rubber-lined aperture and connects +with the soft iron ring, F, that forms the polar expansion. These +pieces are inclosed in a nickelized copper box provided with a +screw cap, C. The resistance of both the receiver and transmitter +bobbin is 200 ohms.</p> + +<p class="ctr"><img src="./illustrations/9c.png" alt= +"FIG. 2.--TRANSMITTER TAKEN APART."></p> + +<p class="ctr">FIG. 2.--TRANSMITTER TAKEN APART.</p> + +<p>The transmitter is 3½ in. in diameter, and is provided +with a re-enforcing mouthpiece. It is regulated by means of a screw +which is fixed in the bottom of the box, and which permits of +varying the distance between the disk and the core that forms the +central pole of the magnet. The regulation, when once effected, +lasts indefinitely. The regulation of the receiver, which is but +2¼ in. in diameter, is performed once for all by the +manufacturer. One of the advantages of this telephone is that its +regulation is permanent. Besides this, it possesses remarkable +power and clearness, and is accompanied with no snuffling sounds, a +fact doubtless owing to all the molecules of the disk being +immersed in the magnetic field, and to the actions of the two poles +occurring concentrically with the disk. As we have above said, this +apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used +by the artillery service in the organization of observatories from +which to watch firing, and the receiver is added to the apparatus +pertaining to military telegraphy. The two small receivers are held +to the lens of the operator by the latter's hat strap, while the +transmitter is suspended in a case supported by straps, with the +mouthpieces near the face (Fig. 1).</p> + +<p>In the figure, the case is represented as open, so as to show +the transmitter. The empty compartment below is designed for the +reception and carriage of the receivers, straps, and flexible +cords. This arrangement permits of calling without the aid of +special apparatus, and it has also the advantage of giving entire +freedom to the man on observation, this being something that is +indispensable in a large number of cases.</p> + +<p class="ctr"><img src="./illustrations/9d.png" alt= +"FIG. 3.--RECEIVER TAKEN APART."></p> + +<p class="ctr">FIG. 3.--RECEIVER TAKEN APART.</p> + +<p>In certain applications, of course, the receivers may be +combined with a microphone; yet on an aerial as well as on a +subterranean line the transmitter produces effects which, as +regards intensity and clearness, are comparable with those of a +pile transmitter.</p> + +<p>Stations wholly magnetic may be established by adding to the +transmitter and two receivers a Sieur phonic call, which will +actuate them powerfully, and cause them to produce a noise loud +enough for a call. It would be interesting to try this telephone on +a city line, and to a great distance on those telegraph lines that +are provided with the Van Rysselberghe system. Excellent results +would certainly be obtained, for, as we have recently been enabled +to ascertain, the voice has a remarkable intensity in this +telephone, while at the same time perfectly preserving its +quality.--<i>La Nature</i>.</p> + +<hr> +<p>[NATURE.]</p> + +<p><a name="15"></a></p> + +<h2>THE MELDOMETER.</h2> + +<p>The apparatus which I propose to call by the above name +(μελδω, to melt) consists of an +adjunct to the mineralogical microscope, whereby the melting-points +of minerals may be compared or approximately determined and their +behavior watched at high temperatures either alone or in the +presence of reagents.</p> + +<p>As I now use it, it consists of a narrow ribbon of platinum (2 +mm. wide) arranged to traverse the field of the microscope. The +ribbon, clamped in two brass clamps so as to be readily renewable, +passes bridgewise over a little scooped-out hollow in a disk of +ebony (4 cm. diam.). The clamps also take wires from a battery (3 +Groves cells); and an adjustable resistance being placed in +circuit, the strip can be thus raised in temperature up to the +melting-point of platinum.</p> + +<p>The disk being placed on the stage of the microscope the +platinum strip is brought into the field of a 1" objective, +protected by a glass slip from the radiant heat. The observer is +sheltered from the intense light at high temperatures by a wedge of +tinted glass, which further can be used in photometrically +estimating the temperature by using it to obtain extinction of the +field. Once for all approximate estimations of the temperature of +the field might be made in terms of the resistance of the platinum +strip, the variation of such resistance with rise of temperature +being known. Such observations being made on a suitably protected +strip might be compared with the wedge readings, the latter being +then used for ready determinations. Want of time has hindered me +from making such observations up to this.</p> + +<p>The mineral to be experimented on is placed in small fragments +near the center of the platinum ribbon, and closely watched while +the current is increased, till the melting-point of the substance +is apparent. Up to the present I have only used it comparatively, +laying fragments of different fusibilities near the specimen. In +this way I have melted beryl, orthoclase, and quartz. I was much +surprised to find the last mineral melt below the melting-point of +platinum. I have, however, by me as I write, a fragment, formerly +clear rock-crystal, so completely fused that between crossed Nicols +it behaves as if an amorphous body, save in the very center where a +speck of flashing color reveals the remains of molecular symmetry. +Bubbles have formed in the surrounding glass.</p> + +<p>Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way.</p> + +<p>Topaz whitens to a milky glass--apparently decomposing, throwing +out filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot +platinum, causes rings of color to appear round the specimen. I +have now been using the apparatus for nearly a month, and in its +earliest days it led me right in the diagnosis of a microscopical +mineral, iolite, not before found in our Irish granite, I think. +The unlooked-for characters of the mineral, coupled with the +extreme minuteness of the crystals, led me previously astray, until +my meldometer fixed its fusibility for me as far above the +suspected bodies.</p> + +<p>Carbon slips were at first used, as I was unaware of the +capabilities of platinum.</p> + +<p>A form of the apparatus adapted, at Prof. Fitzgerald's +suggestion, to fit into the lantern for projection on the screen +has been made for me by Yeates. In this form the heated conductor +passes both below and above the specimen, which is regarded from a +horizontal direction.</p> + +<p>J. JOLY.</p> + +<p>Physical Laboratory, Trinity College, Dublin.</p> + +<hr> +<p>[AMERICAN ANNALS OF THE DEAF AND DUMB.]</p> + +<p><a name="16"></a></p> + +<h2>TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF +DEAF-MUTES.</h2> + +<p>Progress in electrical science is daily causing the world to +open its eyes in wonder and the scientist to enlarge his hopes for +yet greater achievements. The practical uses to which this subtile +fluid, electricity, is being put are causing changes to be made in +time-tested methods of doing things in domestic, scientific, and +business circles, and the time has passed when startling +propositions to accomplish this or that by the assistance of +electricity are dismissed with incredulous smiles. This being the +case, no surprise need follow the announcement of a device to +facilitate the imparting of instruction to deaf children which +calls into requisition some service from electricity.</p> + +<p>The sense of touch is the direct medium contemplated, and it is +intended to convey, with accuracy and rapidity, messages from the +operator (the teacher) to the whole class simultaneously by +electrical transmission.[1]</p> + +<p>[Footnote 1: By the same means two deaf-mutes, miles apart, +might converse with each other, and the greatest difficulty in the +way of a deaf-mute becoming a telegraph operator, that of receiving +messages, would be removed. The latter possibilities are +incidentally mentioned merely as of scientific interest, and not +because of their immediate practical value. The first mentioned use +to which the device may be applied is the one considered by the +writer as possibly of practical value, the consideration of which +suggested the appliance to him.]</p> + +<p>An alphabet is formed upon the palm of the left hand and the +inner side of the fingers, as shown by the accompanying cut, which, +to those becoming familiar with it, requires but a touch upon a +certain point of the hand to indicate a certain letter of the +alphabet.</p> + +<p>A rapid succession of touches upon various points of the hand is +all that is necessary in spelling a sentence. The left hand is the +one upon which the imaginary alphabet is formed, merely to leave +the right hand free to operate without change of position when two +persons only are conversing face to face.</p> + +<p>The formation of the alphabet here figured is on the same +principle as one invented by George Dalgarno, a Scottish +schoolmaster, in the year 1680, a cut of which maybe seen on page +19 of vol. ix. of the <i>Annals</i>, accompanying the reprint of a +work entitled "<i>Didascalocophus</i>." Dalgarno's idea could only +have been an alphabet to be used in conversation between two +persons <i>tête à tête</i>, and--except to a +limited extent in the Horace Mann School and in Professor Bell's +teaching--has not come into service in the instruction of +deaf-mutes or as a means of conversation. There seems to have been +no special design or system in the arrangement of the alphabet into +groups of letters oftenest appearing together, and in several +instances the proximity would seriously interfere with distinct +spelling; for instance, the group "u," "y," "g," is formed upon the +extreme joint of the little finger. The slight discoverable system +that seems to attach to his arrangement of the letters is the +placing of the vowels in order upon the points of the fingers +successively, beginning with the thumb, intended, as we suppose, to +be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly +as another. If any arrangement has advantage over another, we +consider it the one which has so grouped the letters as to admit of +an increased rapidity of manipulation. The arrangement of the above +alphabet, it is believed, does admit of this. Yet it is not claimed +that it is as perfect as the test of actual use may yet make it. +Improvements in the arrangement will, doubtless, suggest +themselves, when the alterations can be made with little need of +affecting the principle.</p> + +<p>In order to transmit a message by this alphabet, the following +described appliance is suggested: A matrix of cast iron, or made of +any suitable material, into which the person receiving the message +(the pupil) places his left hand, palm down, is fixed to the table +or desk. The matrix, fitting the hand, has twenty-six holes in it, +corresponding in position to the points upon the hand assigned to +the different letters of the alphabet. In these holes are small +styles, or sharp points, which are so placed as but slightly to +touch the hand. Connected with each style is a short line of wire, +the other end of which is connected with a principal wire leading +to the desk of the operator (the teacher), and there so arranged as +to admit of opening and closing the circuit of an electric current +at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric +impulses, intended to act mechanically upon all the styles +connected with it. By these impulses, produced by the will of the +sender, the styles are driven upward with a quick motion, but with +only sufficient force to be felt and located upon the hand by the +recipient. Twenty-six of these principal or primary wires are run +from the teacher's desk (there connected with as many buttons) +under the floor along the line of pupils' desks. From each matrix +upon the desk run twenty-six secondary wires down to and severally +connecting with the twenty-six primary wires under the floor. The +whole system of wires is incased so as to be out of sight and +possibility of contact with foreign substances. The keys or buttons +upon the desk of the teacher are systematically arranged, somewhat +after the order of those of the type writer, which allows the use +of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," +"c," etc., to "z," and an electric current over the primary wire +running from a certain button (say the one labeled "a") affects +only those secondary wires connected with the styles that, when +excited, produce upon the particular spot of the hands of the +receivers the tactile impression to be interpreted as "a." And so, +whenever the sender touches any of the buttons on his desk, +immediately each member of the class feels upon the palm of his +hand the impression meant to be conveyed. The contrivance will +admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric +bell. It was first thought of conveying the impressions directly by +slight electric shocks, without the intervention of further +mechanical apparatus, but owing to a doubt as to the physical +effect that might be produced upon the persons receiving, and as to +whether the nerves might not in time become partly paralyzed or so +inured to the effect as to require a stronger and stronger current, +that idea was abandoned, and the one described adopted. A diagram +of the apparatus was submitted to a skillful electrical engineer +and machinist of Hartford, who gave as his opinion that the scheme +was entirely feasible, and that a simple and comparatively +inexpensive mechanism would produce the desired result.</p> + +<p class="ctr"><img src="./illustrations/10a.png" alt= +"TOUCH TRANSMISSION BY ELECTRICITY."></p> + +<p class="ctr">TOUCH TRANSMISSION BY ELECTRICITY.</p> + +<p>The matter now to consider, and the one of greater interest to +the teacher of deaf children, is, Of what utility can the device be +in the instruction of deaf-mutes? What advantage is there, not +found in the prevailing methods of communication with the deaf, +i.e., by gestures, dactylology, speech and speech-reading, and +writing?</p> + +<p>I. The language of gestures, first systematized and applied to +the conveying of ideas to the deaf by the Abbe de l'Epee during the +latter part of the last century, has been, in America, so developed +and improved upon by Gallaudet, Peet, and their successors, as to +leave but little else to be desired for the purpose for which it +was intended. The rapidity and ease with which ideas can be +expressed and understood by this "language" will never cease to be +interesting and wonderful, and its value to the deaf can never fail +of being appreciated by those familiar with it. But the genius of +the language of signs is such as to be in itself of very little, if +any, direct assistance in the acquisition of syntactical language, +owing to the diversity in the order of construction existing +between the English language and the language of signs. Sundry +attempts have been made to enforce upon the sign-language +conformity to the English order, but they have, in all cases known +to the writer, been attended with failure. The sign-language is as +immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given +with great success upon the basis of the sign-language. But in all +such exercises there must be a translation from one language to the +other. The desideratum still exists of an increased percentage of +pupils leaving our schools for the deaf, possessing a facility of +expression in English vernacular. This want has been long felt, and +endeavoring to find a reason for the confessedly low percentage, +the sign-language has been too often unjustly accused. It is only +when the sign-language is abused that its merit as a means of +instruction degenerates. The most ardent admirers of a proper use +of signs are free to admit that any excessive use by the pupils, +which takes away all opportunities to express themselves in +English, is detrimental to rapid progress in English +expression.</p> + +<p>II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as +one of the elements of the American or eclectic method. This +advantage, however, is not of so great importance as to outweigh +the disadvantages when, as has honestly been attempted, it asserts +its independence of other methods. Very few persons indeed, even +after long practice, become sufficiently skillful in spelling on +the fingers to approximate the rapidity of speech. But were it +possible for all to become rapid spellers, another very important +requisite is necessary before the system could be a perfect one, +that is, the ability to <i>read</i> rapid spelling. The number of +persons capable of reading the fingers beyond a moderate degree of +rapidity is still less than the number able to spell rapidly. While +it is physically possible to follow rapid spelling for twenty or +thirty minutes, it can scarcely be followed longer than that. So +long as this is true, dactylology can hardly claim to be more than +one of the <i>elements</i> of a system of instruction for the +deaf.</p> + +<p>III. Articulate speech is another of the elements of the +eclectic method, employed with success inversely commensurate with +the degree of deficiency arising from deafness. Where the English +order is already fixed in his mind, and he has at an early period +of life habitually used it, there is comparatively little +difficulty in instructing the deaf child by speech, especially if +he have a quick eye and bright intellect. But the number so favored +is a small percentage of the great body of deaf-mutes whom we are +called upon to educate. When it is used as a <i>sole</i> means of +educating the deaf as a class its inability to stand alone is as +painfully evident as that of any of the other component parts of +the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to +what a word is if spelled slowly enough, and if its meaning has +been learned. This cannot be said of speech. Between many words +there is not, when uttered, the slightest visible distinction. +Between a greater number of others the distinction is so slight as +to cause an exceedingly nervous hesitation before a guess can be +given. Too great an imposition is put upon the eye to expect it to +follow unaided the extremely circumscribed gestures of the organs +of speech visible in ordinary speaking. The ear is perfection as an +interpreter of speech to the brain. It cannot correctly be said +that it is <i>more</i> than perfection. It is known that the ear, +in the interpretation of vocal sounds, is capable of distinguishing +as many as thirty-five sounds per second (and oftentimes more), and +to follow a speaker speaking at the rate of more than two hundred +words per minute. If this be perfection, can we expect the +<i>eye</i> of ordinary mortal to reach it? Is there wonder that the +task is a discouraging one for the deaf child?</p> + +<p>But it has been asserted that while a large percentage +(practically all) of the deaf <i>can</i>, by a great amount of +painstaking and practice, become speech readers in some small +degree, a relative degree of facility in articulation is not nearly +so attainable. As to the accuracy of this view, the writer cannot +venture an opinion. Judging from the average congenital deaf-mute +who has had special instruction in speech, it can safely be +asserted that their speech is laborious, and far, very far, from +being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that +as an unaided means of instruction it cannot be a success, for +English neither understood when spoken, nor spoken by the pupil, +cannot but remain a foreign language, requiring to pass through +some other form of translation before it becomes intelligible.</p> + +<p>There are the same obstacles in the use of the written or +printed word as have been mentioned in connection with dactylology, +namely, lack of rapidity in conveying impressions through the +medium of the English sentence.</p> + +<p>I have thus hastily reviewed the several means which teachers +generally are employing to impart the use of English to deaf +pupils, for the purpose of showing a common difficulty. The many +virtues of each have been left unnoticed, as of no pertinence to +this article.</p> + +<p>The device suggested at the beginning of this paper, claiming to +be nothing more than a school room appliance intended to supplement +the existing means for giving a knowledge and practice of English +to the deaf, employs as its interpreter a different sense from the +one universally used. The sense of sight is the sole dependence of +the deaf child. Signs, dactylology, speech reading, and the written +and printed word are all dependent upon the eye for their value as +educational instruments. It is evident that of the two senses, +sight and touch, if but one could be employed, the choice of sight +as the one best adapted for the greatest number of purposes is an +intelligent one; but, as the choice is not limited, the question +arises whether, in recognizing the superior adaptability to our +purpose of the one, we do not lose sight of a possibly important, +though secondary, function in the other. If sight were +all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we +acquire our vernacular is of divine, and not of human, origin, and +the senses designed for special purposes are not interchangeable +without loss. The theory that the loss of a certain sense is +nearly, if not quite, compensated for by increased acuteness of the +remaining ones has been exploded. Such a theory accuses, in +substance, the Maker of creating something needless, and is +repugnant to the conceptions we have of the Supreme Being. When one +sense is absent, the remaining senses, in order to equalize the +loss, have imposed upon them an unusual amount of activity, from +which arises skill and dexterity, and by which the loss of the +other sense is in some measure alleviated, but not supplied. No +<i>additional</i> power is given to the eye after the loss of the +sense of hearing other than it might have acquired with the same +amount of practice while both faculties were active. The fact, +however, that the senses, in performing their proper functions, are +not overtaxed, and are therefore, in cases of emergency, capable of +being extended so as to perform, in various degrees, additional +service, is one of the wise providences of God, and to this fact is +due the possibility of whatever of success is attained in the work +of educating the deaf, as well as the blind.</p> + +<p>In the case of the blind, the sense of touch is called into +increased activity by the absence of the lost sense; while in the +case of the deaf, sight is asked to do this additional service. A +blind person's education is received principally through the +<i>two</i> senses of hearing and touch. Neither of these faculties +is so sensible to fatigue by excessive use as is the sense of +sight, and yet the eye has, in every system of instruction applied +to the deaf, been the sole medium. In no case known to the writer, +excepting in the celebrated case of Laura Bridgman and a few others +laboring under the double affliction of deafness and blindness, has +the sense of touch been employed as a means of instruction.[1]</p> + +<p>[Footnote 1: This article was written before Professor Bell had +made his interesting experiments with his "parents' class" of a +touch alphabet, to be used upon the pupil's shoulder in connection +with the oral teaching.--E.A.F.]</p> + +<p>Not taking into account the large percentage of myopes among the +deaf, we believe there are other cogent reasons why, if found +practicable, the use of the sense of touch may become an important +element in our eclectic system of teaching. We should reckon it of +considerable importance if it were ascertained that a portion of +the same work now performed by the eye could be accomplished +equally as well through feeling, thereby relieving the eye of some +of its onerous duties.</p> + +<p>We see no good reason why such accomplishment may not be +wrought. If, perchance, it were discovered that a certain portion +could be performed in a more efficient manner, its value would thus +be further enhanced.</p> + +<p>In theory and practice, the teacher of language to the deaf, by +whatever method, endeavors to present to the eye of the child as +many completed sentences as are nominally addressed to the +ear--having them "caught" by the eye and reproduced with as +frequent recurrence as is ordinarily done by the child of normal +faculties.</p> + +<p>In our hasty review of the methods now in use we noted the +inability to approximate this desirable process as a common +difficulty. The facility now ordinarily attained in the +manipulation of the type writer, and the speed said to have been +reached by Professor Bell and a private pupil of his by the +Dalgarno touch alphabet, when we consider the possibility of a less +complex mechanism in the one case and a more systematic grouping of +the alphabet in the other, would lead us to expect a more rapid +means of communication than is ordinarily acquired by dactylology, +speech (by the deaf), or writing. Then the ability to receive the +communication rapidly by the sense of feeling will be far greater. +No part of the body except the point of the tongue is as sensible +to touch as the tips of the fingers and the palm of the hand. +Tactile discrimination is so acute as to be able to interpret to +the brain significant impressions produced in very rapid +succession. Added to this advantage is the greater one of the +absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the +tympanum of the ear. To sum up, then, the advantages of the device +we find--</p> + +<p>First. A more rapid means of communication with the deaf by +syntactic language, admitting of a greater amount of practice +similar to that received through the ear by normal children.</p> + +<p>Second. Ability to receive this rapid communication for a longer +duration and without ocular strain.</p> + +<p>Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender.</p> + +<p>Fourth. In articulation and speech-reading instruction, the +power to assist a class without distracting the attention of the +eye from the vocal organs of the teacher.</p> + +<p>Fifth. Freedom of the right hand of the pupil to make +instantaneous reproduction in writing of the matter being received +through the sense of feeling, thereby opening the way for a +valuable class exercise.</p> + +<p>Sixth. The possible mental stimulus that accompanies the mastery +of a new language, and the consequent ability to receive known +ideas through a new medium.</p> + +<p>Seventh. A fresh variety of class exercises made possible.</p> + +<p>The writer firmly believes in the good that exists in all +methods that are, or are to be; in the interdependence rather than +the independence of all methods; and in all school-room appliances +tending to supplement or expedite the labors of the teacher, +whether they are made of materials delved from the earth or +snatched from the clouds.</p> + +<p>S. TEFFT WALKER,</p> + +<p><i>Superintendent of the Kansas Institution, Olathe, +Kans</i>.</p> + +<hr> +<p><a name="11"></a></p> + +<h2>WATER GAS.</h2> + +<h3>THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON +REDUCING AGENTS.</h3> + +<h3>By B.H. THWAITE.</h3> + +<p>In order to approximately ascertain the relative reducing action +of water gas, carbon monoxide, and superheated steam on iron ore, +the author decided to have carried out the following experiments, +which were conducted by Mr. Carl J. Sandahl, of Stockholm, who also +carried out the analyses. The ore used was from Bilbao, and known +as the Ruby Mine, and was a good average hematite. The carbonaceous +material was the Trimsaran South Wales anthracite, and contained +about 90 per cent. of carbon.</p> + +<p>A small experimental furnace was constructed of the form shown +by illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the +base, and gradually swelling to 2 ft. 9 in. at the top, built +entirely of fireclay bricks. Two refractory tubes, 2 in. square +internally, and the height of the furnace, were used for the double +purpose of producing the gas and reducing the ore.</p> + +<p>The end of the lower tube rested on a fireclay ladle nozzle, and +was properly jointed with fireclay; through this nozzle the steam +or air was supplied to the inside of the refractory tubes. In each +experiment the ore and fuel were raised to the temperature "of from +1,800 to 2,200 deg. Fahr." by means of an external fire of +anthracite. Great care was taken to prevent the contact of the +solid carbonaceous fuel with the ore. In each experiment in which +steam was used, the latter was supplied at a temperature equivalent +to 35 lb. to the square inch.</p> + +<p>The air for producing the carbon monoxide (CO) gas was used at +the temperature of the atmosphere. As near as possible, the same +conditions were obtained in each experiment, and the equivalent +weight of air was sent through the carbon to generate the same +weight of CO as that generated when steam was used for the +production of water gas.</p> + +<p class="ctr"><img src="./illustrations/11a.png" alt=""></p> + +<p><i>First Experiment, Steam (per se)</i>.--Both tubes, A and B, +were filled with ore broken to the size of nuts. The tube, A, was +heated to about 2,000 deg. Fahr., the upper one to about 1,500 +deg.</p> + +<p>NOTE.--In this experiment, part of the steam was dissociated in +passing through the turned-up end of the steam supply pipe, which +became very hot, and the steam would form with the iron the +magnetic oxide (Fe<sub>3</sub>O<sub>4</sub>). The reduction would +doubtless be due to this dissociation. The pieces of ore found on +lowest end of the tube, A, were dark colored and semi-fused; part +of one of these pieces was crushed fine, and tested; see column I. +The remainder of these black pieces was mixed with the rest of the +ore contained in tube, A, and ground and tested; see column II. The +ore in upper tube was all broken up together and tested; see column +III. When finely crushed, the color of No. I. was bluish black; No. +II., a shade darker red; No. III., a little darker than the natural +color of the ore. The analyses gave:</p> + +<pre> +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- +</pre> + +<p><i>Second Experiment, Water Gas</i>.--The tube, A, was filled +with small pieces of anthracite, and heated until all the volatile +matter had been expelled. The tube, B, was then placed in tube, A, +the joint being made with fireclay, and to prevent the steam from +carrying small particles of solid carbon into ore in the upper +tube, the anthracite was divided from the ore by means of a piece +of fine wire gauze. The steam at a pressure of about 35 lb. to the +square inch was passed through the anthracite. The tube, A, was +heated to white heat, the tube, B, at its lower end to bright red, +the top to cherry red.</p> + +<pre> +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ +</pre> + +<p><i>Four Samples were Tested</i>.--I. The bottom layer, 1¼ +in. thick; the color of ore quite black, with small particles of +reduced spongy metallic iron. II. Layer above I., 4¼ in. +thick; the color was also black, but showed a little purple tint. +III. Layer above II., 5 in. thick; purple red color. IV. Layer +above III., ore a red color. The analyses gave:</p> + +<pre> +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- +</pre> + +<p>NOTE.--All the carbon dioxide (CO<sub>2</sub>) occurring in the +ore as calcic carbonate was expelled.</p> + +<p><i>Third Experiment, Carbon monoxide</i> (CO).--The tube A was +filled with anthracite in the manner described for the second +experiment, and heated to drive off the volatile matter, before the +ore was placed in the upper tube, B, and the anthracite was divided +from the ore by means of a piece of fine wire gauze. The lower +tube, A, was heated to the temperature of white heat, the upper +one, B, to a temperature of bright red. I. Layer, 1 in. thick from +the bottom; ore dark brownish colored. II. Layer 4 in. thick above +I.; ore reddish brown. III. Layer 11 in. thick above II.; ore red +color. The analyses gave:</p> + +<pre> +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- +</pre> + +<p>NOTE.--The carbon monoxide (CO) had failed to remove from the +ore the carbon dioxide existing as calcic carbonate. The summary of +experiments in the following table appears to show that the water +gas is a more powerful reducing agent than CO in proportion to the +ratio of as</p> + +<pre> + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 +</pre> + +<p>Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just +now constructing large experimental plant in which water gas will +be used as the reducing agent. This plant would have been at work +before this but for some defects in the valvular arrangements, +which will be entirely removed in the new modifications of the +plant.</p> + +<hr> +<h2>ANTISEPTIC MOUTH WASH.</h2> + +<p>Where an antiseptic mouth wash is needed, Mr. Sewill prescribes +the use of perchloride of mercury in the following form: One grain +of the perchloride and 1 grain of chloride of ammonium to be +dissolved in 1 oz. of eau de Cologne or tincture of lemons, and a +teaspoonful of the solution to be mixed with two-thirds of a +wineglassful of water, making a proportion of about 1 of +perchloride in 5,000 parts.--<i>Chemist and Druggist</i>.</p> + +<hr> +<p><a name="1"></a></p> + +<h2>ANNATTO.</h2> + +<p>[Footnote: Read at an evening meeting of the North British +Branch of the Pharmaceutical Society, January 21.]</p> + +<h3>By WILLIAM LAWSON.</h3> + +<p>The subject which I have the honor to bring shortly before your +notice this evening is one that formed the basis of some +instructive remarks by Dr. Redwood in November, 1855, and also of a +paper by Dr. Hassall, read before the Society in London in January, +1856, which latter gave rise to an animated discussion. The work +detailed below was well in hand when Mr. MacEwan drew my attention +to these and kindly supplied me with the volume containing reports +of them. Unfortunately, they deal principally with the +adulterations, while I was more particularly desirous to learn the +composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. +Within the last few years it was one of the articles in +considerable demand in this part of the country; now it is seldom +inquired for. This, certainly, is not because butter coloring has +ceased to be employed, and hence the reason for regretting that the +percentage of resin was not dealt with in the articles referred to, +so that a comparison could have been made between the commercial +annatto of that period and that which exists now. In case some may +not be in possession of literature bearing on it--which, by the +way, is very meager--it may not be out of place to quote some short +details as to its source, the processes for obtaining it, the +composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has +more interest for the country than for the town druggist, still, I +trust it will have points of interest for both.</p> + +<p>Annatto is the coloring matter derived from the seeds of an +evergreen plant, <i>Bixa Orellana</i>, which grows in the East and +West Indian Islands and South America, in the latter of which it is +principally prepared. Two kinds are imported, Spanish annatto, made +in Brazil, and flag or French, made mostly in Cayenne. These differ +considerably in characters and properties, the latter having a +disagreeable putrescent odor, while the Spanish is rather agreeable +when fresh and good. It is, however, inferior to the flag as a +coloring or dyeing agent. The seeds from which the substance is +obtained are red on the outside, and two methods are followed in +order to obtain it. One is to rub or wash off the coloring matter +with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to +bruise the seeds, mix them with water, and allow fermentation to +set in, during which the coloring matter collects at the bottom, +from which it is subsequently removed and brought to the proper +consistence by spontaneous evaporation. These particulars, culled +from Dr. Redwood's remarks, may suffice to show its source and the +methods for obtaining it.</p> + +<p>Dr. John gives the following as the composition of the pulp +surrounding the seeds: Coloring resinous matter, 28; vegetable +gluten, 26.5; ligneous fiber, 20; coloring, 20; extractive matter, +4; and a trace of spicy and acid matter.</p> + +<p>It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as +well as to preserve it, differs considerably from this; and though +it may not be true, as some hint, that manufacturing in this +industry is simply a term synonymous with adulterating, yet results +will afterward be given tending to show that there are articles in +the market which have little real claim to the title. I tried, but +failed, to procure a sample of raw material on which to work, with +a view to learn something of its characters and properties in this +state, and thus be able to contrast it with the manufactured or +commercial article. The best thing to do in the circumstances, I +thought, was to operate on the highest priced sample at disposal, +and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the +usual way, I believe--was a more troublesome operation than it +appeared to be, as the following experiment will show: One hundred +grains of No. 8 were taken, dried thoroughly, reduced to fine +powder, and introduced into a flask containing 4 ounces of alcohol +in the form of methylated spirit, boiled for an hour--the flask +during the operation being attached to an inverted +condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated +with diminishing quantities until in all 14 ounces had been used +before the alcoholic solution ceased to turn blue on the addition +to it of strong sulphuric acid, or failed to give a brownish +precipitate with stannous chloride. As the sample contained a +considerable quantity of potassium carbonate, in which the resin is +soluble, it was thought that by neutralizing this it might render +the resin more easy of extraction. This was found to be so, but it +was accompanied by such a mass of extractive as made it in the long +run more troublesome, and hence it was abandoned. Thinking the +spirit employed might be too weak, an experiment with commercial +absolute alcohol was carried out as follows: One hundred grains of +a red sample, No. 4, were thoroughly dried, powdered finely, and +boiled in 2 ounces of the alcohol, filtered, and the residue +treated with half an ounce more. This required to be repeated with +fresh half ounces of the alcohol until in all 7½ were used; +the time occupied from first to last being almost three hours. This +was considered unsatisfactory, besides being very expensive, and so +it, also, was set aside, and a series of experiments with +methylated spirit alone was set in hand. The results showed that +the easiest and most satisfactory way was to take 100 grains (this +amount being preferred, as it reduces error to the minimum), dry +thoroughly, powder finely, and macerate with frequent agitation for +twenty-four hours in a few ounces of spirit, then to boil in this +spirit for a short time, filter, and repeat the boiling with a +fresh ounce or so; this, as a rule, sufficing to completely exhaust +it of its resin. Wynter Blyth says that the red resin, or bixin, is +soluble in 25 parts of hot alcohol. It appears from these +experiments that much more is required to dissolve it out of +commercial annatto.</p> + +<p>The full process followed consisted in determining the moisture +by drying 100 grains at 212° F. till constant, and taking this +dried portion for estimation of the resin in the way just stated. +The alcoholic extract was evaporated to dryness over a water-bath, +the residue dissolved in solution of sodium carbonate, and the +resin precipitated by dilute sulphuric acid (these reagents being +chosen as the best after numerous trials with others), added in the +slightest possible excess. The resin was collected on a tared +double filter paper, washed with distilled water until the washings +were entirely colorless, dried and weighed.</p> + +<p>The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of +them.</p> + +<p>The results are as follows:</p> + +<pre> + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 +</pre> + +<p>The first six are the ordinary red rolls, with the exception of +No. 4, which is a red mass, the only one of this class direct from +the manufacturers. The remainder are brown cakes, all except No. 7 +being from the manufacturers direct. The ash of the first two was +largely common salt; that of No. 3 contained, besides this, iron in +some quantity. No. 4 is unique in many respects. It was of a bright +red color, and possessed a not disagreeable odor. It contained the +largest percentage of moisture and the lowest of ash; had, +comparatively, a large amount of coloring matter; was one of the +cheapest, and in the course of some dairy trials, carried out by an +intelligent farmer, was pronounced to be the best suited for +coloring butter. So far as my experience goes, it was a sample of +the best commercial excellence, though I fear the mass of water +present and the absence of preserving substances will assist in its +speedy decay. Were such an article easily procured in the usual way +of business, there would not be much to complain of, but it must +not be forgotten that it was got direct from the manufacturers--a +somewhat suggestive fact when the composition of some other samples +is taken into account. No. 5 emitted a disagreeable odor during +ignition. The soluble portion of the ash was mostly common salt, +and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter +gave rise to disagreeable reflections. It was wrapped in a paper +saturated with a strongly smelling linseed oil. When it was boiled +in water and broken up, hairs, among other things, were observed +floating about. It contained some iron. The first cake, No. 7, gave +off during ignition an agreeable odor resembling some of the finer +tobaccos, and this is characteristic more or less of all the cakes. +The ash weighed 52 per cent., the soluble part of which, 18.5, was +mostly potassium carbonate, with some chlorides and sulphates; the +insoluble, mostly chalk with iron and alumina. No. 8--highest +priced of all--had in the mass an odor which I can compare to +nothing else than a well rotted farmyard manure. Twenty parts of +the ash were soluble and largely potassium carbonate, the insoluble +being iron for the most part. The mineral portions of Nos. 9 and 10 +closely resemble No. 7.</p> + +<p>On looking over the results, it is found that the red rolls +contained starchy matters in abundance (in No. 4 the starch was to +a large extent replaced by water), and an ash, mostly sodium +chloride, introduced no doubt to assist in its preservation as well +as to increase the color of the resin--a well known action of salt +on vegetable reds. The cakes, which are mostly used for cheese +coloring, I believe, all appeared to contain turmeric, for they +gave a more or less distinct reaction with the boric acid test, and +all except No. 8 contained large quantities of chalk. These results +in reference to extractive, etc., reveal nothing that has not been +known before. Wynter Blyth, who gives the only analyses of annatto +I have been able to find, states that the composition of a fair +commercial sample (which I take to mean the raw article) examined +by him was as follows: water, 24.2; resin, 28.8; ash, 22.5; and +extractive, 24.5; and that of an adulterated (which I take to mean +a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. +27.3. If this be correct, it appears that the articles at present +in the market, or at least those which have come in my way, have +been wretched imitations of the genuine thing, and should, instead +of being called adulterated annatto, be called something else +adulterated, but not seriously, with annatto. I have it on the +authority of the farmer previously referred to, that ¼ of an +ounce of No. 4 is amply sufficient to impart the desired cowslip +tint to no less than 60 lb. of butter. When so little is actually +required, it does not seem of very serious importance whether the +adulterant or preservative be flour, chalk, or water, but it is +exasperating in a very high degree to have such compounds as Nos. 3 +and 6 palmed off as decent things when even Nos. 1, 2, and 5 have +been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may +be induced to examine the annatto taken into stock more closely +than I was taught to do, and had been in the habit of doing, +namely, to see if it had a good consistence and an odor resembling +black sugar, for if so, the quality was above suspicion.</p> + +<hr> +<p><a name="12"></a></p> + +<h2>JAPANESE RICE WINE AND SOJA SAUCE.</h2> + +<p>Professor P. Cohn has recently described the mode in which he +has manufactured the Japanese sake or rice wine in the laboratory. +The material used was "Tane Kosi," i.e., grains of rice coated with +the mycelium, conidiophores, and greenish yellow chains of conidia +of <i>Aspergillus Oryzoe</i>. The fermentation is caused by the +mycelium of this fungus before the development of the +fructification. The rice is first exposed to moist air so as to +change the starch into paste, and then mixed with grains of the +"Tane Kosi." The whole mass of rice becomes in a short time +permeated by the soft white shining mycelium, which imparts to it +the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two +or three days, and then subjected to alcoholic fermentation from +the <i>Saccharomyces</i>, which is always present in the rice, but +which has nothing to do with the <i>Aspergillus</i>. The +fermentation is completed in two or three weeks, and the golden +yellow, sherry-like sake is poured off. The sample manufactured +contained 13.9 per cent. of alcohol. Chemical investigation showed +that the <i>Aspergillus</i> mycelium transforms the starch into +glucose, and thus plays the part of a diastase.</p> + +<p>Another substance produced from the <i>Aspergillus</i> rice is +the soja sauce. The soja leaves, which contain little starch, but a +great deal of oil and casein, are boiled, mixed with roasted +barley, and then with the greenish yellow conidia powder of the +<i>Aspergillus</i>. After the mycelium has fructified, the mass is +treated with a solution of sodium chloride, which kills the +<i>Aspergillus</i>, another fungus, of the nature of a +<i>Chalaza</i>, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce +then separates.</p> + +<hr> +<p><a name="2"></a></p> + +<h2>ALUMINUM.</h2> + +<p>[Footnote: Annual address delivered by President J.A. Price +before the meeting of the Scranton Board of Trade, Monday, January +18, 1886.]</p> + +<h3>By J.A. PRICE.</h3> + +<p>Iron is the basis of our civilization. Its supremacy and power +it is impossible to overestimate; it enters every avenue of +development, and it may be set down as the prime factor in the +world's progress. Its utility and its universality are hand in +hand, whether in the magnificent iron steamship of the ocean, the +network of iron rail upon land, the electric gossamer of the air, +or in the most insignificant articles of building, of clothing, and +of convenience. Without it, we should have miserably failed to +reach our present exalted station, and the earth would scarcely +maintain its present population; it is indeed the substance of +substances. It is the Archimedean lever by which the great human +world has been raised. Should it for a moment forget its cunning +and lose its power, earthquake shocks or the wreck of matter could +not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that +it must give way to a metal that has still greater proportions and +vaster possibilities. Strange and startling as may seem the +assertion, yet I believe it nevertheless to be true that we are +approaching the period, if not already standing upon the threshold +of the day, when this magical element will be radically supplanted, +and when this valuable mineral will be as completely superseded as +the stone of the aborigines. With all its apparent potency, it has +its evident weaknesses; moisture is everywhere at war with it, +gases and temperature destroy its fiber and its life, continued +blows or motion crystallize and rob it of its strength, and acids +will devour it in a night. If it be possible to eliminate all, or +even one or more, of these qualities of weakness in any metal, +still preserving both quantity and quality, that metal will be the +metal of the future.</p> + +<p>The coming metal, then, to which our reference is made is +aluminum, the most abundant metal in the earth's crust. Of all +substances, oxygen is the most abundant, constituting about +one-half; after oxygen comes silicon, constituting about +one-fourth, with aluminum third in all the list of substances of +the composition. Leaving out of consideration the constituents of +the earth's center, whether they be molten or gaseous, more or less +dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we +find that aluminum is beyond question the most abundant and the +most useful of all metallic substances.</p> + +<p>It is the metallic base of mica, feldspar, slate, and clay. +Professor Dana says: "Nearly all the rocks except limestones and +many sandstones are literally ore-beds of the metal aluminum." It +appears in the gem, assuming a blue in the sapphire, green in the +emerald, yellow in the topaz, red in the ruby, brown in the emery, +and so on to the white, gray, blue, and black of the slates and +clays. It has been dubbed "clay metal" and "silver made from clay;" +also when mixed with any considerable quantity of carbon becoming a +grayish or bluish black "alum slate."</p> + +<p>This metal in color is white and next in luster to silver. It +has never been found in a pure state, but is known to exist in +combination with nearly two hundred different minerals. Corundum +and pure emery are ores that are very rich in aluminum, containing +about fifty-four per cent. The specific gravity is but two and +one-half times that of water; it is lighter than glass or as light +as chalk, being only one-third the weight of iron and one-fourth +the weight of silver; it is as malleable as gold, tenacious as +iron, and harder than steel, being next the diamond. Thus it is +capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. +Its variety of transformations is something wonderful. Meeting +iron, or even iron at its best in the form of steel, in the same +field, it easily vanquishes it at every point. It melts at 1,300 +degrees F., or at least 600 degrees below the melting point of +iron, and it neither oxidizes in the atmosphere nor tarnishes in +contact with gases. The enumeration of the properties of aluminum +is as enchanting as the scenes of a fairy tale.</p> + +<p>Before proceeding further with this new wonder of science, which +is already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French +chemist Lavoisier, a very magician in the science, groping in the +dark of the last century, evolved the chemical theory of +combustion--the existence of a "highly respirable gas," oxygen, and +the presence of metallic bases in earths and alkalies. With the +latter subject we have only to do at the present moment. The +metallic base was predicted, yet not identified. The French +Revolution swept this genius from the earth in 1794, and darkness +closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon +the metallic base of certain earths, but the reflection was so +feeble that the great secret was never revealed. Then a little +later the Swedish Berzelius and the Danish Oersted, confident in +the prediction of Lavoisier and of Davy, went in search of the +mysterious stranger with the aggressive electric current, but as +yet to no purpose. It was reserved to the distinguished German +Wohler, in 1827, to complete the work of the past fifty years of +struggle and finally produce the minute white globule of the pure +metal from a mixture of the chloride of aluminum and sodium, and at +last the secret is revealed--the first step was taken. It took +twenty years of labor to revolve the mere discovery into the +production of the aluminum bead in 1846, and yet with this first +step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come.</p> + +<p>Returning again to France some time during the years between +1854 and 1858, and under the patronage of the Emperor Napoleon +III., we behold Deville at last forcing Nature to yield and give up +this precious quality as a manufactured product. Rose, of Berlin, +and Gerhard, in England, pressing hard upon the heels of the +Frenchman, make permanent the new product in the market at +thirty-two dollars per pound. The despair of three-quarters of a +century of toilsome pursuit has been broken, and the future of the +metal has been established.</p> + +<p>The art of obtaining the metal since the period under +consideration has progressed steadily by one process after another, +constantly increasing in powers of productivity and reducing the +cost. These arts are intensely interesting to the student, but must +be denied more than a reference at this time. The price of the +metal may be said to have come within the reach of the +manufacturing arts already.</p> + +<p>A present glance at the uses and possibilities of this wonderful +metal, its application and its varying quality, may not be out of +place. Its alloys are very numerous and always satisfactory; with +iron, producing a comparative rust proof; with copper, the +beautiful golden bronze, and so on, embracing the entire list of +articles of usefulness as well as works of art, jewelry, and +scientific instruments.</p> + +<p>Its capacity to resist oxidation or rust fits it most eminently +for all household and cooking utensils, while its color transforms +the dark visaged, disagreeable array of pots, pans, and kitchen +implements into things of comparative beauty. As a metal it +surpasses copper, brass, and tin in being tasteless and odorless, +besides being stronger than either.</p> + +<p>It has, as we have seen, bulk without weight, and consequently +may be available in construction of furniture and house fittings, +as well in the multitudinous requirements of architecture. The +building art will experience a rapid and radical change when this +material enters as a component material, for there will be +possibilities such as are now undreamed of in the erection of +homes, public buildings, memorial structures, etc. etc., for in +this metal we have the strength, durability, and the color to give +all the variety that genius may dictate.</p> + +<p>And when we take a still further survey of the vast field that +is opening before us, we find in the strength without size a most +desirable assistant in all the avenues of locomotion. It is the +ideal metal for railway traffic, for carriages and wagons. The +steamships of the ocean of equal size will double their cargo and +increase the speed of the present greyhounds of the sea, making six +days from shore to shore seem indeed an old time calculation and +accomplishment. A thinner as well as a lighter plate; a smaller as +well as a stronger engine; a larger as well as a less hazardous +propeller; and a natural condition of resistance to the action of +the elements; will make travel by water a forcible rival to the +speed attained upon land, and bring all the distant countries in +contact with our civilization, to the profit of all. This metal is +destined to annihilate space even beyond the dream of philosopher +or poet.</p> + +<p>The tensile strength of this material is something equally +wonderful, when wire drawn reaches as high as 128,000 pounds, and +under other conditions reaches nearly if not quite 100,000 pounds +to the square inch. The requirements of the British and German +governments in the best wrought steel guns reach only a standard of +70,000 pounds to the square inch. Bridges may be constructed that +shall be lighter than wooden ones and of greater strength than +wrought steel and entirely free from corrosion. The time is not +distant when the modern wonder of the Brooklyn span will seem a +toy.</p> + +<p>It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube.</p> + +<p>The resistance to corrosion evidently fits this metal for +railway sleepers to take the place of the decaying wooden ties. In +this metal the sleeper may be made as soft and yielding as lead, +while the rail may be harder and tougher than steel, thus at once +forming the necessary cushion and the avoidance of jar and noise, +at the same time contributing to additional security in virtue of a +stronger rail.</p> + +<p>In conductivity this metal is only exceeded by copper, having +many times that of iron. Thus in telegraphy there are renewed +prospects in the supplanting of the galvanized iron +wire--lightness, strength, and durability. When applied to the +generation of steam, this material will enable us to carry higher +pressure at a reduced cost and increased safety, as this will be +accomplished by the thinner plate, the greater conductivity of +heat, and the better fiber.</p> + +<p>It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in +the mechanic art lies dormant--the size of the machine may be +reduced, the speed and the power increased, realizing the +conception of two things better done than one before. It is one of +man's creative acts.</p> + +<p>From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, +Paris, asserts that 120,000 blows will exhaust the usefulness of +the cushion of the stamp machine, and this number of blows is given +in a day; and that when a cushion of aluminum bronze was +substituted, it was unaffected after months of use.</p> + +<p>If we have found a metal that possesses both tensile strength +and resistance to compression; malleability and ductility--the +quality of hardening, softening, and toughening by tempering; +adaptability to casting, rolling, or forging; susceptibility to +luster and finish; of complete homogeneous character and unusually +resistant to destructive agents--mankind will certainly leave the +present accomplishments as belonging to an effete past, and, as it +were, start anew in a career of greater prospects.</p> + +<p>This important material is to be found largely in nearly all the +rocks, or as Prof. Dana has said, "Nearly all rocks are ore-beds of +the metal." It is in every clay bank. It is particularly abundant +in the coal measures and is incidental to the shales or slates and +clays that underlie the coal. This under clay of the coal stratum +was in all probability the soil out of which grew the vegetation of +the coal deposits. It is a compound of aluminum and other matter, +and, when mixed with carbon and transformed by the processes of +geologic action, it becomes the shale rock which we know and which +we discard as worthless slate. And it is barely possible that we +have been and are still carting to the refuse pile an article more +valuable than the so greatly lauded coal waste or the merchantable +coal itself. We have seen that the best alumina ore contains only +fifty-four per cent. of metal.</p> + +<p>The following prepared table has been furnished by the courtesy +and kindness of Mr. Alex. H. Sherred, of Scranton.</p> + +<pre> + ALUMINA. +<br> +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 +</pre> + +<p>It will be seen that the black clay, shale, or slate, has a +constituent of aluminum of from 15.93 per cent., the lowest, to +32.60 per cent., the highest. Under every stratum of coal, and +frequently mixed with it, are these under deposits that are rich in +the metal. When exposed to the atmosphere, these shales yield a +small deposit of alum. In the manufacture of alum near Glasgow the +shale and slate clay from the old coal pits constitute the material +used, and in France alum is manufactured directly from the +clay.</p> + +<p>Sufficient has been advanced to warrant the additional assertion +that we are here everywhere surrounded by this incomparable +mineral, that it is brought to the surface from its deposits deep +in the earth by the natural process in mining, and is only exceeded +in quantity by the coal itself. Taking a columnar section of our +coal field, and computing the thickness of each shale stratum, we +have from twenty-five to sixty feet in thickness of this +metal-bearing substance, which averages over twenty-five per cent. +of the whole in quantity in metal.</p> + +<p>It is readily apparent that the only task now before us is the +reduction of the ore and the extraction of the metal. Can this be +done? We answer, it has been done. The egg has stood on end--the +new world has been sighted. All that now remains is to repeat the +operation and extend the process. Cheap aluminum will revolutionize +industry, travel, comfort, and indulgence, transforming the present +into an even greater civilization. Let us see.</p> + +<p>We have seen the discovery of the mere chemical existence of the +metal, we have stood by the birth of the first white globule or +bead by Wohler, in 1846, and witnesssed its introduction as a +manufactured product in 1855, since which time, by the alteration +and cheapening of one process after another, it has fallen in price +from thirty-two dollars per pound in 1855 to fifteen dollars per +pound in 1885. Thirty years of persistent labor at smelting have +increased the quantity over a thousandfold and reduced the cost +upward of fifty per cent.</p> + +<p>All these processes involve the application of heat--a mere +question of the appliances. The electric currents of Berzelius and +Oersted, the crucible of Wohler, the closed furnaces and the +hydrogen gas of the French manufacturers and the Bessemer converter +apparatus of Thompson, all indicate one direction. This metal can +be made to abandon its bed in the earth and the rock at the will of +man. During the past year, the Messrs. Cowles, of Cleveland, by +their electric smelting process, claim to have made it possible to +reduce the price of the metal to below four dollars per pound; and +there is now erecting at Lockport, New York, a plant involving one +million of capital for the purpose.</p> + +<p>Turning from the employment of the expensive reducing agents to +the simple and sole application of heat, we are unwilling to +believe that we do not here possess in eminence both the mineral +and the medium of its reduction. Whether the electric or the +reverberatory or the converter furnace system be employed, it is +surely possible to produce the result.</p> + +<p>To enter into consideration of the details of these +constructions would involve more time than is permitted us on this +occasion. They are very interesting. We come again naturally to the +limitless consideration of powdered fuel, concerning which certain +conclusions have been reached. In the dissociation of water into +its hydrogen and oxygen, with the mingled carbon in a powdered +state, we undoubtedly possess the elements of combustion that are +unexcelled on earth, a heat-producing combination that in both +activity and power leaves little to be desired this side of the +production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and +furnaces.</p> + +<p>In the hope of stimulating thought to this infinite question of +proper fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope +this Board will not grudgingly devote to the subject, but which is +impossible at present. Do not forget that there is no single spot +on the face of the globe where nature has lavished more freely her +choicest gifts. Let us be active in the pursuit of the treasure and +grateful for the distinguished consideration.</p> + +<hr> +<p><a name="19"></a></p> + +<h2>THE ORIGIN OF METEORITES.</h2> + +<p>On January 9, Professor Dewar delivered the sixth and last of +his series of lectures at the Royal Institution on "The Story of a +Meteorite." [For the preceding lectures, see SUPPLEMENTS 529 and +580.] He said that cosmic dust is found on Arctic snows and upon +the bottom of the ocean; all over the world, in fact, at some time +or other, there has been a large deposit of this meteoric dust, +containing little round nodules found also in meteorites. In +Greenland some time ago numbers of what were supposed to be +meteoric stones were found; they contained iron, and this iron, on +being analyzed at Copenhagen, was found to be rich in nickel. The +Esquimaux once made knives from iron containing nickel; and as any +such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited +the basaltic coast in Greenland from which some of the supposed +meteoric stones had been brought, and in the middle of the rock +large nodules were found composed of iron and nickel; it, +therefore, became evident that the earth might produce masses not +unlike such as come to us as meteorites. The lecturer here +exhibited a section of the Greenland rock containing the iron, and +nickel alloy, mixed with stony crystals, and its resemblance to a +section of a meteorite was obvious. It was 2½ times denser +than water, yet the whole earth is 5½ times denser than +water, so that if we could go deep enough, it is not improbable +that our own globe might be found to contain something like +meteoric iron. He then called attention to the following +tables:</p> + +<pre> + <i>Elementary Substances found in Meteorites</i>. +<br> + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. +</pre> + +<p><i>Density of Meteorites</i>.</p> + +<pre> + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 +</pre> + +<p><i>Interior of the Earth</i></p> + +<pre> + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 +</pre> + +<p class="ctr"><img src="./illustrations/13a.png" alt=""></p> + +<p>Twice a year, said Professor Dewar, what are called "falling +stars" maybe plentifully seen; the times of their appearance are in +August and November. Although thousands upon thousands of such +small meteors have passed through our atmosphere, there is no +distinct record of one having ever fallen to the earth during these +annual displays. One was said to have fallen recently at Naples, +but on investigation it turned out to be a myth. These annual +meteors in the upper air are supposed to be only small ones, and to +be dissipated into dust and vapor at the time of their sudden +heating; so numerous are they that 40,000 have been counted in one +evening, and an exceptionally great display comes about once in +33¼ years. The inference from their periodicity is, that +they are small bodies moving round the sun in orbits of their own, +and that whenever the earth crosses their orbits, thereby getting +into their path, a splendid display of meteors results. A second +display, a year later, usually follows the exceptionally great +display just mentioned, consequently the train of meteors is of +great length. Some of these meteors just enter the atmosphere of +the earth, then pass out again forever, with their direction of +motion altered by the influence of the attraction of the earth. He +here called attention to the accompanying diagram of the orbits of +meteors.</p> + +<p>The lecturer next invited attention to a hollow globe of linen +or some light material; it was about 2 ft. or 2 ft. 6 in. in +diameter, and contained hidden within it the great electro-magnet, +weighing 2 cwt., so often used by Faraday in his experiments. He +also exhibited a ball made partly of thin iron; the globe +represented the earth, for the purposes of the experiment, and the +ball a meteorite of somewhat large relative size. The ball was then +discharged at the globe from a little catapult; sometimes the globe +attracted the ball to its surface, and held it there, sometimes it +missed it, but altered its curve of motion through the air. So was +it, said the lecturer, with meteorites when they neared the earth. +Photographs from drawings, by Professor A. Herschel, of the paths +of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, +is a proof that their motions are parallel to each other; the +parallel lines seem to draw to a point at the greatest distance, +for the same reason that the rails of a straight line of railway +seem to come from a distant central point. The most interesting +thing about the path of a company of meteors is, that a comet is +known to move in the same orbit; the comet heads the procession, +the meteors follow, and they are therefore, in all probability, +parts of comets, although everything about these difficult matters +cannot as yet be entirely explained; enough, however, is known to +give foundation for the assumption that meteorites and comets are +not very dissimilar.</p> + +<p>The light of a meteorite is not seen until it enters the +atmosphere of the earth, but falling meteorites can be vaporized by +electricity, and the light emitted by their constituents be then +examined with the spectroscope. The light of comets can be directly +examined, and it reveals the presence in those bodies of sodium, +carbon, and a few other well-known substances. He would put a piece +of meteorite in the electric arc to see what light it would give; +he had never tried the experiment before. The lights of the theater +were then turned down, and the discourse was continued in darkness; +among the most prominent lines visible in the spectrum of the +meteorite, Professor Dewar specified magnesium, sodium, and +lithium. "Where do meteorites come from?" said the lecturer. It +might be, he continued, that they were portions of exploded +planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular +hypothesis that at some long past time our sun and all his planets +existed but as a volume of gas, which in contracting and cooling +formed a hot volume of rotating liquid, and that as this further +contracted and cooled, the planets, and moons, and planetary rings +fell off from it and gradually solidified, the sun being left as +the solitary comparatively uncooled portion of the original nebula. +In partial illustration of this, he caused a little globe of oil, +suspended in an aqueous liquid of nearly its own specific gravity, +to rotate, and as it rotated it was seen, by means of its magnified +image upon the screen, to throw off from its outer circumference +rings and little globes.</p> + +<hr> +<p><a name="17"></a></p> + +<h2>CANDELABRA CACTUS AND CALIFORNIA WOODPECKER.</h2> + +<h3>By C.F. HOLDER.</h3> + +<p>One of the most picturesque objects that meet the eye of the +traveler over the great plains of the southern portion of +California and New Mexico is the candelabra cactus. Systematically +it belongs to the Cereus family, in which the notable +Night-blooming Cereus also is naturally included. In tropical or +semi-tropical countries these plants thrive, and grow to enormous +size. For example, the Cereus that bears those great flowers, and +blooms at night, exhaling powerful perfume, as we see them in +hothouses in our cold climate, are even in the semi-tropical region +of Key West, on the Florida Reef, seen to grow enormously in +length.</p> + +<p class="ctr"><a href="./illustrations/14a.png"><img src= +"./illustrations/14a_th.jpg" alt= +"THE CANDELABRA CACTUS--CEREUS GIGANTEUS."></a></p> + +<p class="ctr">THE CANDELABRA CACTUS--CEREUS GIGANTEUS.</p> + +<p>We cultivated several species of the more interesting forms +during a residence on the reef. Our brick house, two stories in +height, was entirely covered on a broad gable end, the branches +more than gaining the top. There is a regular monthly growth, and +this is indicated by a joint between each two lengths. Should the +stalk be allowed to grow without support, it will continue growing +without division, and exhibit stalks five or six feet in length, +when they droop, and fall upon the ground.</p> + +<p>Where there is a convenient resting place on which it can spread +out and attach itself, the stalk throws out feelers and rootlets, +which fasten securely to the wall or brickwork; then, this being a +normal growth, there is a separation at intervals of about a foot. +That is, the stalk grows in one month about twelve inches, and if +it has support, the middle woody stalk continues to grow about an +inch further, but has no green, succulent portion, in fact, looks +like a stem; then the other monthly growth takes place, and ends +with a stem, and so on indefinitely. Our house was entirely covered +by the stems of such a plant, and the flowers were gorgeous in the +extreme. The perfume, however, was so potent that it became a +nuisance. Such is the Night-blooming Cereus in the warm climates, +and similarly the Candelabra Cereus grows in stalks, but +architecturally erect, fluted like columns. The flowers are large, +and resemble those of the night-blooming variety. Some columns +remain single, and are amazingly artificial appearing; others throw +off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being +clusters of side shoots, the latter putting out from the trunk +regularly, and standing up parallel to each other. The enormous +size these attain is well shown in the picture.</p> + +<p>Whenever the great stalks of these cacti die, the succulent +portion is dried, and nothing is left but the woody fiber. They are +hollow in places, and easily penetrated. A species of woodpecker, +<i>Melanerpes formicivorus</i>, is found to have adopted the use of +these dry stalks for storing the winter's stock of provisions. +There are several round apertures seen on the stems in the +pictures, which were pecked by this bird. This species of +woodpecker is about the size of our common robin or migratory +thrush, and has a bill stout and sharp. The holes are pecked for +the purpose of storing away acorns or other nuts; they are just +large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts +are so numerous, the stalk has the appearance of being studded with +bullets. This appearance is more pronounced in cases where the dead +trunk of an oak is used. There are some specimens of the latter now +owned by the American Museum of Natural History, which were +originally sent to the Centennial Exhibition at Philadelphia. They +were placed in the department contributed by the Pacific Railroad +Company, and at that time were regarded as some of the wonders of +that newly explored region through which the railroad was then +penetrating. Some portions of the surface of these logs are nearly +entirely occupied by the holes with acorns in them. The acorns are +driven in very tightly in these examples; much more so than in the +cactus plants, as the oak is nearly round, and the holes were +pecked in solid though dead wood. One of the most remarkable +circumstances connected with this habit of the woodpecker is the +length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to +make a journey of sixty miles to accomplish the storing of one +acorn. At first it seemed strange that a bird should spend so much +labor to place those bits of food, and so far away. De Saussure, a +Swiss naturalist, published in the <i>Bibliotheque Universelle</i>, +of Geneva, entertaining accounts of the Mexican Colaptes, a variety +of the familiar "high hold," or golden winged woodpecker. They were +seen to store acorns in the dead stalks of the maguey (<i>Agave +Americana</i>). Sumichrast, who accompanied him to Central America, +records the same facts. These travelers saw great numbers of the +woodpeckers in a region on the slope of a range of volcanic +mountains. There was little else of vegetation than the +<i>Agave</i>, whose barren, dead stems were studded with acorns +placed there by the woodpeckers.</p> + +<p>The maguey throws up a stalk about fifteen feet in height +yearly, which, after flowering, grows stalky and brittle, and +remains an unsightly thing. The interior is pithy, but after the +death of the stalk the pith contracts, and leaves the greater +portion of the interior hollow, as we have seen in the case of the +cactus branches. How the birds found that these stalks were hollow +is a problem not yet solved, but, nevertheless, they take the +trouble to peck away at the hard bark, and once penetrated, they +commence to fill the interior; when one space is full, the bird +pecks a little higher up, and so continues.</p> + +<p>Dr. Heerman, of California, describes the California +<i>Melanerpes</i> as one of the most abundant of the woodpeckers; +and remarks that it catches insects on the wing like a flycatcher. +It is well determined that it also eats the acorns that it takes so +much pains to transport.</p> + +<p class="ctr"><img src="./illustrations/14b.png" alt= +"FLOWER OF CEREUS GIGANTEUS."></p> + +<p class="ctr">FLOWER OF CEREUS GIGANTEUS.</p> + +<p>It seems that these birds also store the pine trees, as well as +the oaks. It is not quite apparent why these birds exhibit such +variation in habits; they at times select the more solid trees, +where the storing cannot go on without each nut is separately set +in a hole of its own. There seems an instinct prompting them to do +this work, though there may not be any of the nuts touched again by +the birds. Curiously enough, there are many instances of the birds +placing pebbles instead of nuts in holes they have purposely pecked +for them. Serious trouble has been experienced by these pebbles +suddenly coming in contact with the saw of the mill through which +the tree is running. The stone having been placed in a living tree, +as is often the case, its exterior had been lost to sight during +growth.</p> + +<p>Some doubt has been entertained about the purpose of the bird in +storing the nuts in this manner. De Saussure tells us he has +witnessed the birds eating the acorns after they had been placed in +holes in trees, and expresses his conviction that the insignificant +grub which is only seen in a small proportion of nuts is not the +food they are in search of.</p> + +<p>C.W. Plass, Esq., of Napa City, California, had an interesting +example of the habits of the California <i>Melanerpes</i> displayed +in his own house. The birds had deposited numbers of acorns in the +gable end. A considerable number of shells were found dropped +underneath the eaves, while some were found in place under the +gable, and these were perfect, having no grubs in them.</p> + +<p>The picture shows a very common scene in New Mexico. The +columns, straight and angular, are often sixty feet in height. It +is called torch cactus in some places. There are many varieties, +and as many different shapes. Some lie on the ground; others, +attached to trunks of trees as parasites, hang from branches like +great serpents; but none is so majestic as the species called +systematically <i>Cereus giganteus</i>, most appropriately. The +species growing pretty abundantly on the island of Key West is +called candle cactus. It reaches some ten or twelve feet, and is +about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a +pretty, rather picturesque feature in the otherwise barren +undergrowth of shrubbery and small trees. Accompanied by a few +flowering cocoa palms, the view is not unpleasing. The fiber of +these plants is utilized in some coarse manufactures. The maguey, +or Agave, is used in the manufacture of fine roping. Manila hemp is +made from a species. The species whose dried stalks are used by the +woodpeckers for their winter storage was cultivated at Key West, +Florida, during several years before 1858. Extensive fields of the +Agave stood unappropriated at that period. Considerable funds were +dissipated on this venture. Extensive works were established, and +much confidence was entertained that the scheme would prove a +paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their +long stalks, stand now, increasing every year, until a portion of +the island is overrun with them.</p> + +<h3>CEREUS GIGANTEUS.</h3> + +<p>This wonderful cactus, its colossal proportions, and weird, yet +grand, appearance in the rocky regions of Mexico and California, +where it is found in abundance, have been made known to us only +through books of travel, no large plants of it having as yet +appeared in cultivation in this country. It is questionable if ever +the natural desire to see such a vegetable curiosity represented by +a large specimen in gardens like Kew can be realized, owing to the +difficulty of importing large stems in a living condition; and even +if successfully brought here, they survive only a very short time. +To grow young plants to a large size seems equally beyond our +power, as plants 6 inches high and carefully managed are quite ten +years old. When young, the stem is globose, afterward becoming +club-shaped or cylindrical. It flowers at the height of 12 feet, +but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of +an immense candelabrum, the base of the stem being as thick as a +man's body. The flower, of which a figure is given here, is about 5 +inches long and wide, the petals cream colored, the sepals greenish +white. Large clusters of flowers are developed together near the +top of the stem. A richly colored edible fruit like a large fig +succeeds each flower, and this is gathered by the natives and used +as food under the name of saguarro. A specimen of this cactus 3 +feet high may be seen in the succulent house at Kew.--<i>B., The +Garden</i>.</p> + +<hr> +<p><a name="18"></a></p> + +<h2>HOW PLANTS ARE REPRODUCED.</h2> + +<p>[Footnote: Read at a meeting of the Chemists' Assistants' +Association. December 16, 1885.]</p> + +<h3>By C.E. STUART, B.Sc.</h3> + +<p>In two previous papers read before this Association I have tried +to condense into as small a space as I could the processes of the +nutrition and of the growth of plants; in the present paper I want +to set before you the broad lines of the methods by which plants +are reproduced.</p> + +<p>Although in the great trees of the conifers and the dicotyledons +we have apparently provision for growth for any number of years, or +even centuries, yet accident or decay, or one of the many ills that +plants are heirs to, will sooner or later put an end to the life of +every individual plant.</p> + +<p>Hence the most important act of a plant--not for itself perhaps, +but for its race--is the act by which it, as we say, "reproduces +itself," that is, the act which results in the giving of life to a +second individual of the same form, structure, and nature as the +original plant.</p> + +<p>The methods by which it is secured that the second generation of +the plant shall be as well or even better fitted for the struggle +of life than the parent generation are so numerous and complicated +that I cannot in this paper do more than allude to them; they are +most completely seen in cross fertilization, and the adaptation of +plant structures to that end.</p> + +<p>What I want to point out at present are the principles and not +so much the details of reproduction, and I wish you to notice, as I +proceed, what is true not only of reproduction in plants but also +of all processes in nature, namely, the paucity of typical methods +of attaining the given end, and the multiplicity of special +variation from those typical methods. When we see the wonderfully +varied forms of plant life, and yet learn that, so to speak, each +edifice is built with the same kind of brick, called a cell, +modified in form and function; when we see the smallest and +simplest equally with the largest and most complicated plant +increasing in size subject to the laws of growth by intussusception +and cell division, which are universal in the organic world; we +should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types.</p> + +<p>The first great generalization is into--</p> + +<p>1. The vegetative type of reproduction, in which one or more +ordinary cells separate from the parent plant and become an +independent plant; and--</p> + +<p>2. The special-cell type of reproduction, in which either one +special cell reproduces the plant, or two special cells by their +union form the origin of the new plant; these two modifications of +the process are known respectively as asexual and sexual.</p> + +<p>The third modification is a combination of the two others, +namely, the asexual special cell does not directly reproduce its +parent form, but gives rise to a structure in which sexual special +cells are developed, from whose coalescence springs again the +likeness of the original plant. This is termed alternation of +generations.</p> + +<p>The sexual special cell is termed the <i>spore</i>.</p> + +<p>The sexual special cells are of one kind or of two kinds.</p> + +<p>Those which are of one kind may be termed, from their habit of +yoking themselves together, <i>zygoblasts</i>, or conjugating +cells.</p> + +<p>Those which are of two kinds are, first, a generally aggressive +and motile fertilizing or so-called "male cell," called in its +typical form an <i>antherozoid</i>; and, second, a passive and +motionless receptive or so-called "female cell," called an +<i>oosphere</i>.</p> + +<p>The product of the union of two zygoblasts is termed a +<i>zygospore</i>.</p> + +<p>The product of the union of an antherozoid and an oosphere is +termed an <i>oospore</i>.</p> + +<p>In many cases the differentiation of the sexual cells does not +proceed so far as the formation of antherozoids or of distinct +oospheres; these cases I shall investigate with the others in +detail presently.</p> + +<p>First, then, I will point out some of the modes of vegetative +reproduction.</p> + +<p>The commonest of these is cell division, as seen in unicellular +plants, such as protococcus, where the one cell which composes the +plant simply divides into two, and each newly formed cell is then a +complete plant.</p> + +<p>The particular kind of cell division termed "budding" here +deserves mention. It is well seen in the yeast-plant, where the +cell bulges at one side, and this bulge becomes larger until it is +nipped off from the parent by contraction at the point of junction, +and is then an independent plant.</p> + +<p>Next, there is the process by which one plant becomes two by the +dying off of some connecting portion between two growing parts.</p> + +<p>Take, for instance, the case of the liverworts. In these there +is a thallus which starts from a central point and continually +divides in a forked or dichotomous manner. Now, if the central +portion dies away, it is obvious that there will be as many plants +as there were forkings, and the further the dying of the old end +proceeds, the more young plants will there be.</p> + +<p>Take again, among higher plants, the cases of suckers, runners, +stolons, offsets, etc. Here, by a process of growth but little +removed from the normal, portions of stems develop adventitious +roots, and by the dying away of the connecting links may become +independent plants.</p> + +<p>Still another vegetative method of reproduction is that by +bulbils or gemmæ.</p> + +<p>A bulbil is a bud which becomes an independent plant before it +commences to elongate; it is generally fleshy, somewhat after the +manner of a bulb, hence its name. Examples occur in the axillary +buds of <i>Lilium bulbiferum</i>, in some <i>Alliums</i>, etc.</p> + +<p>The gemma is found most frequently in the liverworts and mosses, +and is highly characteristic of these plants, in which indeed +vegetative reproduction maybe said to reach its fullest and most +varied extent.</p> + +<p>Gemmæ are here formed in a sort of flat cup, by division +of superficial cells of the thallus or of the stem, and they +consist when mature of flattened masses of cells, which lie loose +in the cup, so that wind or wet will carry them away on to soil or +rock, when, either by direct growth from apical cells, as with +those of the liverworts, or with previous emission of thread-like +cells forming a "protonema," in the case of the mosses, the young +plant is produced from them.</p> + +<p>The lichens have a very peculiar method of gemmation. The +lichen-thallus is composed of chains or groups of round +chlorophyl-containing cells, called "gonidia," and masses of +interwoven rows of elongated cells which constitute the +hyphæ. Under certain conditions single cells of the gonidia +become surrounded with a dense felt of hyphæ, these +accumulate in numbers below the surface of the thallus, until at +last they break out, are blown or washed away, and start +germination by ordinary cell division, and thus at once reproduce a +fresh lichen-thallus. These masses of cells are called soredia.</p> + +<p>Artificial budding and grafting do not enter into the scope of +this paper.</p> + +<p>As in the general growth and the vegetative reproduction of +plants cell-division is the chief method of cell formation, so in +the reproduction of plants by special cells the great feature is +the part played by cells which are produced not by the ordinary +method of cell division, but by one or the other processes of cell +formation, namely, free-cell formation or rejuvenescence.</p> + +<p>If we broaden somewhat the definition of rejuvenescence and +free-cell formation, and do not call the mother-cells of spores of +mosses, higher cryptogams, and also the mother-cells of +pollen-grains, reproductive cells, which strictly speaking they are +not, but only producers of the spores or pollen-grains, then we may +say that <i>cell-division is confined to vegetative processes, +rejuvenescence and free-cell formation are confined to reproductive +processes</i>.</p> + +<p>Rejuvenescence may be defined as the rearrangement of the whole +of the protoplasm of a cell into a new cell, which becomes free +from the mother-cell, and may or may not secrete a cell-wall around +it.</p> + +<p>If instead of the whole protoplasm of the cell arranging itself +into one mass, it divides into several, or if portions only of the +protoplasm become marked out into new cells, in each case +accompanied by rounding off and contraction, the new cells +remaining free from one another, and usually each secreting a cell +wall, then this process, whose relation to rejuvenescence is +apparent, is called free-cell formation.</p> + +<p>The only case of purely vegetative cell-formation which takes +place by either of these processes is that of the formation of +endosperm in Selaginella and phanerogams, which is a process of +free-cell formation.</p> + +<p>On the other hand, the universal contraction and rounding off of +the protoplasm, and the formation by either rejuvenescence or +free-cell formation, distinctly mark out the special or true +reproductive cell.</p> + +<p>Examples of reproductive cells formed by rejuvenescence are:</p> + +<p>1. The swarm spores of many algæ, as Stigeoclonium +(figured in Sachs' "Botany"). Here the contents of the cell +contract, rearrange themselves, and burst the side of the +containing wall, becoming free as a reproductive cell.</p> + +<p>2. The zygoblasts of conjugating algæ, as in Spirogyra. +Here the contents of a cell contract and rearrange themselves only +after contact of the cell with one of another filament of the +plant. This zygoblast only becomes free after the process of +conjugation, as described below.</p> + +<p>3. The oosphere of characeæ, mosses and liverworts, and +vascular cryptogams, where in special structures produced by +cell-divisions there arise single primordial cells, which divide +into two portions, of which the upper portion dissolves or becomes +mucilaginous, while the lower contracts and rearranges itself to +form the oosphere.</p> + +<p>4. Spores of mosses and liverworts, of vascular cryptogams, and +pollen cells of phanerogams, which are the analogue of the +spores.</p> + +<p>The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes +a wall of its own, and by the bursting or absorption of the wall of +its mother-cell becomes free. This is evidently a +rejuvenescence.</p> + +<p>Examples of reproductive cells formed by free-cell formation +are:</p> + +<p>1. The ascospores of fungi and algæ.</p> + +<p>2. The zoospores or mobile spores of many algæ and +fungi.</p> + +<p>3. The germinal vesicles of phanerogams.</p> + +<p>The next portion of my subject is the study of the methods by +which these special cells reproduce the plant.</p> + +<p>1st. Asexual methods.</p> + +<p>1. Rejuvenescence gives rise to a swarm-spore or zoospore. The +whole of the protoplasm of a cell contracts, becomes rounded and +rearranged, and escapes into the water, in which the plant floats +as a mass of protoplasm, clear at one end and provided with cilia +by which it is enabled to move, until after a time it comes to +rest, and after secreting a wall forms a new plant by ordinary +cell-division. Example: Oedogonium.</p> + +<p>2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya.</p> + +<p>3. Free-cell formation forms the typical motionless spore of +algæ and fungi. For instance, in the asci of lichens there +are formed from a portion of the protoplasm four or more small +ascospores, which secrete a cell-wall and lie loose in the ascus. +Occasionally these spores may consist of two or more cells. They +are set free by the rupture of the ascus, and germinate by putting +out through their walls one or more filaments which branch and form +the thallus of a new individual. Various other spores formed in the +same way are known as <i>tetraspores</i>, etc.</p> + +<p>4. Cell-division with rejuvenescence forms the spores of mosses +and higher cryptogams.</p> + +<p>To take the example of moss spores:</p> + +<p>Certain cells in the sporogonium of a moss are called +mother-cells. The protoplasm of each one of these becomes divided +into four parts. Each of these parts then secretes a cell-wall and +becomes free as a spore by the rupture or absorption of the wall of +the mother-cell. The germination of the spores I shall describe +later.</p> + +<p>5. A process of budding which in the yeast plant and in mosses +is merely vegetatively reproductive, in fungi becomes truly +reproductive, namely, the buds are special cells arising from other +special cells of the hyphæ.</p> + +<p>For example, the so-called "gills" of the common mushroom have +their surface composed of the ends of the threads of cells +constituting the hyphæ. Some of these terminal cells push out +a little finger of protoplasm, which swells, thickens its wall, and +becomes detached from the mother-cell as a spore, here called +specially a <i>basidiospore</i>.</p> + +<p>Also in the common gray mould of infusions and preserves, +Penicillium, by a process which is perhaps intermediate between +budding and cell-division, a cell at the end of a hypha constricts +itself in several places, and the constricted portions become +separate as <i>conidiospores</i>.</p> + +<p><i>Teleutospores, uredospores</i>, etc., are other names for +spores similarly formed.</p> + +<p>These conidiospores sometimes at once develop hyphæ, and +sometimes, as in the case of the potato fungus, they turn out their +contents as a swarm-spore, which actively moves about and +penetrates the potato leaves through the stomata before they come +to rest and elongate into the hyphal form.</p> + +<p>So far for asexual methods of reproduction.</p> + +<p>I shall now consider the sexual methods.</p> + +<p>The distinctive character of these methods is that the cell from +which the new individual is derived is incapable of producing by +division or otherwise that new individual without the aid of the +protoplasm of another cell.</p> + +<p>Why this should be we do not know; all that we can do is to +guess that there is some physical or chemical want which is only +supplied through the union of the two protoplasmic masses. The +process is of benefit to the species to which the individuals +belong, since it gives it a greater vigor and adaptability to +varying conditions, for the separate peculiarities of two +individuals due to climatic or other conditions are in the new +generation combined in one individual.</p> + +<p>The simplest of the sexual processes is conjugation. Here the +two combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union.</p> + +<p>Conjugation occurs in algæ and fungi. A typical case is +that of Spirogyra. This is an alga with its cells in long +filaments. Two contiguous cells of two parallel filaments push each +a little projection from its cell-wall toward the other. When these +meet, the protoplasm of each of the two cells contracts, and +assumes an elliptical form--it undergoes rejuvenescence. Next an +opening forms where the two cells are in contact, and the contents +of one cell pass over into the other, where the two protoplasmic +bodies coalesce, contract, and develop a cell-wall. The zygospore +thus formed germinates after a long period and forms a new filament +of cells.</p> + +<p>Another example of conjugation is that of Pandorina, an alga +allied to the well-known volvox. Here the conjugating cells swim +free in water; they have no cell-wall, and move actively by cilia. +Two out of a number approach, coalesce, contract, and secrete a +cell-wall. After a long period of rest, this zygospore allows the +whole of its contents to escape as a swarm-spore, which after a +time secretes a gelatinous wall, and by division reproduces the +sixteen-celled family.</p> + +<p>We now come to fertilization, where the uniting cells are of two +kinds.</p> + +<p>The simplest case is that of Vaucheria, an alga. Here the +vegetative filament puts out two protuberances, which become shut +off from the body of the filament by partitions. The protoplasm in +one of these protuberances arranges itself into a round mass--the +oosphere or female cell. The protoplasm of the other protuberance +divides into many small masses, furnished with cilia, the +spermatozoids or male cells. Each protuberance bursts, and some of +the spermatozoids come in contact with and are absorbed by the +oosphere, which then secretes a cell-wall, and after a time +germinates.</p> + +<p>The most advanced type of fertilization is that of +angiosperms.</p> + +<p>In them there are these differences from the above process: the +contents of the male cell, represented by the pollen, are not +differentiated into spermatozoids, and there is no actual contact +between the contents of the pollen tube and the germinal vesicle, +but according to Strashurger, there is a transference of the +substance of the nucleus of the pollen cell to that of the germinal +vesicle by osmose. The coalescence of the two nuclei within the +substance of the germinal vesicle causes the latter to secrete a +wall, and to form a new plant by division, being nourished the +while by the mother plant, from whose tissues the young embryo +plant contained in the seed only becomes free when it is in an +advanced stage of differentiation.</p> + +<p>Perhaps the most remarkable cases of fertilization occur in the +Florideæ or red seaweeds, to which class the well-known Irish +moss belongs.</p> + +<p>Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, +some other cell which is quite distinct from the primarily +fertilized cell carries on the reproductive process.</p> + +<p>If the allied group of the Coleochæteæ is considered +together with the Florideæ, we find a transition between the +ordinary case of Coleochæte and that of Dudresnaya. In +Coleochæte, the male cell is a round spermatozoid, and the +female cell an oosphere contained in the base of a cell which is +elongated into an open and hair-like tube called the trichogyne. +The spermatozoid coalesces with the oosphere, which secretes a +wall, becomes surrounded with a covering of cells called a +cystocarp, which springs from cells below the trichogyne, and after +the whole structure falls from the parent plant, spores are +developed from the oospore, and from them arises a new +generation.</p> + +<p>In Dudresnaya, on the other hand, the spermatozoid coalesces +indeed with the trichogyne, but this does not develop further. From +below the trichogyne, however, spring several branches, which run +to the ends of adjacent branches, with the apical cells of which +they conjugate, and the result of this conjugation is the +development of a cystocarp similar to that of Coleochæte. The +remarkable point here is the way in which the effect of the +fertilizing process is carried from one cell to another entirely +distinct from it.</p> + +<p>Thus I have endeavored to sum up the processes of asexual and of +sexual reproduction. But it is a peculiar characteristic of most +classes of plants that the cycle of their existence is not complete +until both methods of reproduction have been called into play, and +that the structure produced by one method is entirely different +from that produced by the other method.</p> + +<p>Indeed, it is only in some algæ and fungi that the +reproductive cells of one generation produce a generation similar +to the parent; in all other plants a generation A produces are +unlike generation B, which may either go on to produce another +generation, C, and then back to A, or it may go on producing B's +until one of these reproduces A, or again it may directly +reproduce; A. Thus we have the three types:</p> + +<pre> + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. +</pre> + +<p>The first case is not common, the usual number of generations +being two only; but a typical example of the occurrence of three +generations is in such fungi as <i>Puccinia Graminis</i>. Here the +first generation grows on barberry leaves, and produces a kind of +spore called an <i>æcidium spore</i>. These æcidium +spores germinate only on a grass stem or leaf, and a distinct +generation is produced, having a particular kind of spore called an +<i>uredospore</i>. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation +with another kind of spore, called a <i>teleutospore</i>, is +produced.</p> + +<p>The teleutospores only germinate on barberry leaves, and there +reproduce the original æcidium generation.</p> + +<p>Thus we have the series A.B.B.B ... BCA</p> + +<p>In this instance all the generations are asexual, but the most +common case is for the sexual and the asexual generations to +alternate. I will describe as examples the reproduction of a moss, +a fern, and a dicotyledon.</p> + +<p>In such a typical moss as Funaria, we have the following cycle +of developments: The sexual generation is a dioecious leafy +structure, having a central elongated axis, with leaves arranged +regularly around and along it. At the top of the axis in the male +plant rise the antheridia, surrounded by an envelope of modified +leaves called the perigonium. The antheridia are stalked sacs, with +a single wall of cells, and the spiral antherozoids arise by +free-cell formation from the cells of the interior. They are +discharged by the bursting of the antheridium, together with a +mucilage formed of the degraded walls of their mother cells.</p> + +<p>In the female plant there arise at the apex of the stem, +surrounded by an envelope of ordinary leaves, several archegonia. +These are of the ordinary type of those organs, namely, a broad +lower portion, containing a naked oosphere and a long narrow neck +with a central canal leading to the oosphere. Down this canal pass +one or more antherozoids, which become absorbed into the oosphere, +and this then secretes a wall, and from it grows the second or +asexual generation. The peculiarity of this asexual or +spore-bearing plant is that it is parasitic on the sexual plant; +the two generations, although not organically connected, yet remain +in close contact, and the spore-bearing generation is at all events +for a time nourished by the leafy sexual generation.</p> + +<p>The spore-bearing generation consists of a long stalk, closely +held below by the cells of the base of the archegonium; this +supports a broadened portion which contains the spores, and the top +is covered with the remains of the neck of the archegonium forming +the calyptra.</p> + +<p>The spores arise from special or mother-cells by a process of +division, or it may be even termed free-cell formation, the +protoplasm of each mother-cell dividing into four parts, each of +which contracts, secretes a wall, and thus by rejuvenescence +becomes a spore, and by the absorption of the mother-cells the +spores lie loose in the spore sac. The spores are set free by the +bursting of their chamber, and each germinates, putting out a +branched thread of cells called a protonema, which may perhaps +properly be termed a third generation in the cycle of the plant; +for it is only from buds developed on this protonema that the leafy +sexual plant arises.</p> + +<p>The characteristics, then, of the mosses are, that the sexual +generation is leafy, the one or two asexual generations are +thalloid, and that the spore-bearing generation is in parasitic +connection with the sexual generation.</p> + +<p>In the case of the fern, these conditions are very +different.</p> + +<p>The sexual generation is a small green thalloid structure called +a prothallium, which bears antheridia and archegonia, each +archegonium having a neck-canal and oosphere, which is fertilized +just as in the moss.</p> + +<p>But the asexual generation derived from the oospore only for a +short while remains in connection with the prothallium, which, of +course, answers to the leafy portion of the moss. What is generally +known as the fern is this asexual generation, a great contrast to +the small leafless moss fruit or sporogonium as it is called, to +which it is morphologically equivalent. On the leaves of this +generation arise the sporangia which contain the spores. The spores +are formed in a manner very similar to those of the mosses, and are +set free by rupture of the sporangium.</p> + +<p>The spore produces the small green prothallium by cell-division +in the usual way, and this completes the cycle of fern life.</p> + +<p>The alternation of generations, which is perhaps most clear and +typical in the case of the fern, becomes less distinctly marked in +the plants of higher organization and type.</p> + +<p>Thus in the Rhizocarpæ there are two kinds of spores, +<i>microspores</i> and <i>macrospores</i>, producing prothallia +which bear respectively antheridia and archegonia; in the +Lycopodiaceæ, the two kinds of spores produce very +rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the +endosperm, in which archegonia or corpuscula are formed; and +lastly, in typical dicotyledons it is only lately that any trace of +a prothallium from the microspore or pollen cell has been +discovered, while the macrospore or embryo-sac produces only two or +three prothallium cells, known as antipodal cells, and two or three +oospheres, known as germinal vesicles.</p> + +<p>This description of the analogies of the pollen and embryo-sac +of dicotyledons assumes that the general vegetative structure of +this class of plants is equivalent to the asexual generation of the +higher cryptogams. In describing their cycle of reproduction I will +endeavor to show grounds for this assumption.</p> + +<p>We start with the embryo as contained in the seed. This embryo +is the product of fertilization of a germinal vesicle by a pollen +tube. Hence, by analogy with the product of fertilization of +rhizocarp's, ferns, and mosses, it should develop into a spore +bearing plant. It does develop into a plant in which on certain +modified leaves are produced masses of tissue in which two kinds of +special reproductive cells are formed. This is precisely analogous +to the case of gymnosperms, lycopods, etc., where on leaf +structures are formed macro and micro sporangia.</p> + +<p>To deal first with the microsporangium or pollen-sac. The pollen +cells are formed from mother cells by a process of cell division +and subsequent setting free of the daughter cells or pollen cells +by rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceæ, etc. The +subsequent behavior of the pollen cell, its division and its +fertilization of the germinal vesicle or oosphere, leave no doubt +as to its analogy with the microspore of vascular cryptogams.</p> + +<p>Secondly, the nucleus of the ovule corresponds with the +macrosporangium of Selaginella, through the connecting link of the +conifers, where the ovule is of similar origin and position to the +macrosporangium of the Lycopodiaceæ. But the formation of the +macrospore or embryo-sac is simpler than the corresponding process +in cryptogams. It arises by a simple enlargement of one cell of the +nucleus instead of by the division of one cell into four, each thus +becoming a macrospore. At the top of this macrospore or embryo-sac +two or three germinal vesicles are formed by free cell formation, +and also two or three cells called antipodal cells, since they +travel to the other end of the embryo-sac; these latter represent a +rudimentary prothallium. This formation of germinal vesicles and +prothallium seems very different from the formation of archegonia +and prothallium in Selaginella, for instance; but the link which +connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed.</p> + +<p>Thus we see that the flowering plant is essentially the +equivalent of the asexual fern, and of the sporogonium of the moss, +and the pollen cell and the embryo-sac represent the two spores of +the higher cryptogams, and the pollen tube and the germinal +vesicles and antipodal cells are all that remain of the sexual +generation, seen in the moss as a leafy plant, and in the fern as a +prothallium. Indeed, when a plant has monoecious or dioecious +flowers, the distinction between the asexual and the sexual +generation has practically been lost, and the spore-bearing +generation has become identified with the sexual generation.</p> + +<p>Having now described the formation of the pollen and the +germinal vesicles, it only remains to show how they form the +embryo. The pollen cell forms two or three divisions, which are +either permanent or soon absorbed; this, as before stated, is the +rudimentary male prothallium. Then when it lies on the stigma it +develops a long tube, which passes down the style and through the +micropyle of the ovule to the germinal vesicles, one of which is +fertilized by what is probably an osmotic transference of nuclear +matter. The germinal vesicle now secretes a wall, divides into two +parts, and while the rest of the embyro-sac fills with endosperm +cells, it produces by cell division from the upper half a short row +of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or +leafy plant, and while in the fern each generation is an +independent structure, here in the dicotyledon, on the other hand, +the asexual generation or embryo is again for a time nourished in +the interior of the embryo-sac representing the sexual generation, +and this again derives its nourishment from the previous asexual +generation, so that as in the moss, there is again a partial +parasitism of one generation on the other.</p> + +<p>To sum up the methods of plant reproduction: They resolve +themselves into two classes.</p> + +<p>1st. Purely vegetative.</p> + +<p>2d. Truly reproductive by special cells.</p> + +<p>In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive +methods.</p> + +<p>1st. Reproduction from an asexual spore.</p> + +<p>2d. Reproduction from an oospore formed by the combination of +two sexual cells.</p> + +<p>In the vast majority of plant species these two types are used +by the individuals alternately.</p> + +<p>The extraordinary similarity of the reproductive process, as +shown in the examples I have given, Achlya, Spirogyra, and +Vaucheria among algæ, the moss, the fern, and the flowering +plant, a similarity which becomes the more marked the more the +details of each case and of the cases of plants which form links +between these great classes are studied, points to a community of +origin of all plants in some few or one primeval ancestor. And to +this inference the study of plant structure and morphology, +together with the evidence of palæobotany among other +circumstances, lends confirmatory evidence, and all modern +discoveries, as for instance that of the rudimentary prothallium +formed by the pollen of angiosperms, tend to the smoothing of the +path by which the descent of the higher plants from simpler types +will, as I think, be eventually shown.</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. 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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, Vol. XXI., No. 531, March 6, 1886 + +Author: Various + +Release Date: February 29, 2004 [EBook #11383] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPP. 531 *** + + + + +Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland, +Charles Franks and the DP Team + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 531 + + + + +NEW YORK, MARCH 6, 1886 + +Scientific American Supplement. Vol. XXI, No. 531. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY AND METALLURGY.--Annatto.-Analyses of the same.--By + WM. LAWSON + + Aluminum.--By J.A. PRICE.--Iron the basis of civilization.-- + Aluminum the metal of the future.--Discovery of aluminum.--Art + of obtaining the metal.--Uses and possibilities + +II. ENGINEERING AND MECHANICS.--The Use of Iron in Fortification. + --Armor-plated casements.--The Schumann-Gruson chilled iron + cupola.--Mougin's rolled iron cupola.--With full page + of engravings + + High Speed on the Ocean + + Sibley College Lectures.--Principles and Methods of Balancing + Forces developed in Moving Bodies.--Momentum and centrifugal + force.--By CHAS.T. PORTER.--3 figures + + Compressed Air Power Schemes.--By J. STURGEON.--Several + figures + + The Berthon Collapsible Canoe.--2 engravings + + The Fiftieth Anniversary of the Opening of the First German + Steam Railroad.--With full page engraving + + Improved Coal Elevator.--With engraving + +III. TECHNOLOGY.--Steel-making Ladles.--4 figures + + Water Gas.--The relative value of water gas and other gases as + Iron-reducing Agents.--By B.H. THWAITE.--Experiments.--With + tables and 1 figure + + Japanese Rice Wine and Soja Sauce.--Method of making + +IV. ELECTRICITY, MICROSCOPY, ETC.-Apparatus for demonstrating + that Electricity develops only on the Surface of Conductors.--1 + figure + + The Colson Telephone.--3 engravings + + The Meldometer.--An apparatus for determining the melting + points of minerals + + Touch Transmission by Electricity in the Education of Deaf + Mutes.--By S. TEFFT WALKER.--With 1 figure + +V. HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By + C.F. HOLDER.--With 2 engravings + + How Plants are reproduced.--By C.E. STUART.--A paper read + before the Chemists' Assistants' Association + +VI. MISCELLANEOUS--The Origin of Meteorites.--With 1 figure + + * * * * * + + + + +THE USE OF IRON IN FORTIFICATION. + + +Roumania is thinking of protecting a portion of the artillery of the +forts surrounding her capital by metallic cupolas. But, before deciding +upon the mode of constructing these formidable and costly affairs, and +before ordering them, she has desired to ascertain their efficacy and +the respective merits of the chilled iron armor which was recently in +fashion and of rolled iron, which looks as if it were to be the fashion +hereafter. + +[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.] + +The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a turret +of rolled iron. Both of these recommend themselves by various merits, +and by remarkably ingenious arrangements, and it only remains to be seen +how they will behave under the fire of the largest pieces of artillery. + +[Illustration: FIG. 2.] + +We are far in advance of the time when cannons with smooth bore were +obliged to approach to within a very short range of a scarp in order to +open a breach, and we are far beyond that first rifled artillery which +effected so great a revolution in tactics. + +[Illustration: FIG. 3.] + +To-day we station the batteries that are to tear open a rampart at +distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch +cannon that arms them has for probable deviations, under a charge of 20 +pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16 +inches in direct fire and 8 inches in curved. + +The weight of the projectile is 88 pounds, and its remanent velocity at +the moment of impact is 1,295 feet. Under this enormous live force, the +masonry gradually crumbles, and carries along the earth of the parapet, +and opens a breach for the assaulting columns. + +[Illustration: FIG. 4--STATE OF A CUPOLA AFTER THE ACTION OF +THIRTY-SEVEN 6 IN. PROJECTILES.] + +In order to protect the masonry of the scarp, engineers first lowered +the cordon to the level of the covert-way. Under these circumstances, +the enemy, although he could no longer see it, reached it by a curved or +"plunging" shot. When, in fact, for a given distance we load a gun with +the heaviest charge that it will stand, the trajectory, AMB (Fig. 2), is +as depressed as possible, and the angles, a and a', at the start and +arrival are small, and we have a direct shot. If we raise the chase of +the piece, the projectile will describe a curve in space which would be +a perfect parabola were it not for the resistance of the air, and the +summit of such curve will rise in proportion as the angle so increases. +So long as the falling angle, a, remains less than 45 deg., we shall have a +curved shot. When the angle exceeds this, the shot is called "vertical." +If we preserve the same charge, the parabolic curve in rising will meet +the horizontal plane at a greater distance off. This is, as well known, +the process employed for reaching more and more distant objects. + +[Illustration: Fig. 5.--STATE OF A CAST-IRON CUPOLA AFTER THE BREAKAGE +OF A VOUSSOIR.] + +The length of a gun depends upon the maximum charge burned in it, since +the combustion must be complete when the projectile reaches the open +air. It results from this that although guns of great length are capable +of throwing projectiles with small charges, it is possible to use +shorter pieces for this purpose--such as howitzers for curved shots and +mortars for vertical ones. The curved shot finds one application in the +opening of breaches in scarp walls, despite the existence of a covering +of great thickness. If, from a point, a (Fig. 3), we wish to strike the +point, b, of a scarp, over the crest, c, of the covert-way, it will +suffice to pass a parabolic curve through these three points--the +unknown data of the problem, and the charge necessary, being +ascertained, for any given piece, from the artillery tables. In such +cases it is necessary to ascertain the velocity at the impact, since the +force of penetration depends upon the live force (mv squared) of the +projectile, and the latter will not penetrate masonry unless it have +sufficient remanent velocity. Live force, however, is not the sole +factor that intervenes, for it is indispensable to consider the angle at +which the projectile strikes the wall. Modern guns, such as the Krupp 6 +inch and De Bange 6 and 8 inch, make a breach, the two former at a +falling angle of 22 deg., and the latter at one of 30 deg.. It is not easy to +lower the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass of the +glacis. + +The same guns are employed for dismounting the defender's pieces, which +he covers as much as possible behind the parapet. Heavy howitzers +destroy the _materiel_, while shrapnel, falling nearly vertically, and +bursting among the men, render all operations impossible upon an open +terre-plein. + +[Illustration: FIG. 6.--STATE OF A CHILLED IRON CUPOLA BROKEN BY A 12 +INCH BALL.] + +The effect of 6 and 8 inch rifled mortars is remarkable. The Germans +have a 9 inch one that weighs 3,850 pounds, and the projectile of which +weighs 300. But French mortars in nowise cede to those of their +neighbors; Col. De Bange, for example, has constructed a 101/2 inch one of +wonderful power and accuracy. + +Seeing the destructive power of these modern engines of war, it may well +be asked how many pieces the defense will be able to preserve intact for +the last period of a siege--for the very moment at which it has most +need of a few guns to hold the assailants in check and destroy the +assaulting columns. Engineers have proposed two methods of protecting +these few indispensable pieces. The first of these consists in placing +each gun under a masonry vault, which is covered with earth on all sides +except the one that contains the embrasure, this side being covered with +armor plate. + +The second consists in placing one or two guns under a metallic cupola, +the embrasures in which are as small as possible. The cannon, in a +vertical aim, revolves around the center of an aperture which may be of +very small dimensions. As regards direct aim, the carriages are +absolutely fixed to the cupola, which itself revolves around a vertical +axis. These cupolas may be struck in three different ways: (1) at right +angles, by a direct shot, and consequently with a full charge--very +dangerous blows, that necessitate a great thickness of the armor plate; +(2) obliquely, when the projectile, if the normal component of its real +velocity is not sufficient to make it penetrate, will be deflected +without doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy. + +General Brialmont says that the metal of the cupola should be able to +withstand both penetration and breakage; but these two conditions +unfortunately require opposite qualities. A metal of sufficient +ductility to withstand breakage is easily penetrated, and, conversely, +one that is hard and does not permit of penetration does not resist +shocks well. Up to the present, casehardened iron (Gruson) has appeared +to best satisfy the contradictory conditions of the problem. Upon the +tempered exterior of this, projectiles of chilled iron and cast steel +break upon striking, absorbing a part of their live force for their own +breakage. + +In 1875 Commandant Mougin performed some experiments with a chilled iron +turret established after these plans. The thickness of the metal +normally to the blows was 231/2 inches, and the projectiles were of cast +steel. The trial consisted in firing two solid 12 in. navy projectiles, +46 cylindrical 6 in. ones, weighing 100 lb., and 129 solid, pointed +ones, 12 in. in diameter. The 6 inch projectiles were fired from a +distance of 3,280 feet, with a remanent velocity of 1,300 feet. The +different phases of the experiment are shown in Figs. 4, 5, and 6. The +cupola was broken; but it is to be remarked that a movable and +well-covered one would not have been placed under so disadvantageous +circumstances as the one under consideration, upon which it was easy to +superpose the blows. An endeavor was next made to substitute a tougher +metal for casehardened iron, and steel was naturally thought of. But +hammered steel broke likewise, and a mixed or compound metal was still +less successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was rolled +iron. Armor plate composed of this latter has been submitted to several +tests, which appear to show that a thickness of 18 inches will serve as +a sufficient barrier to the shots of any gun that an enemy can +conveniently bring into the field. + +[Illustration: FIG. 7.--CASEMATE OF CHILLED IRON AFTER RECEIVING +NINETY-SIX SHOTS.] + +_Armor Plated Casemates_.--Fig. 7 shows the state of a chilled iron +casemate after a vigorous firing. The system that we are about to +describe is much better, and is due to Commandant Mougin. + +[Illustration: FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.] + +The gun is placed under a vault whose generatrices are at right angles +to the line of fire (Fig. 8), and which contains a niche that traverses +the parapet. This niche is of concrete, and its walls in the vicinity of +the embrasure are protected by thick iron plate. The rectangular armor +plate of rolled iron rests against an elastic cushion of sand compactly +rammed into an iron plate caisson. The conical embrasure traverses this +cushion by means of a cast-steel piece firmly bolted to the caisson, and +applied to the armor through the intermedium of a leaden ring. +Externally, the cheeks of the embrasure and the merlons consist of +blocks of concrete held in caissons of strong iron plate. The +surrounding earthwork is of sand. For closing the embrasure, Commandant +Mougin provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected by +the sloping mass of concrete that covers the head of the casemate. A +windlass and chain give the disk the motion that brings one of its +apertures opposite the embrasure or that closes the latter. When this +portion of the disk has suffered too much from the enemy's fire, a +simple maneuver gives it a half revolution, and the second aperture is +then made use of. + +_The Schumann-Gruson Chilled Iron Cupola_.--This cupola (Fig. 9) is +dome-shaped, and thus offers but little surface to direct fire; but it +can be struck by a vertical shot, and it may be inquired whether its top +can withstand the shock of projectiles from a 10 inch rifled mortar. It +is designed for two 6 inch guns placed parallel. Its internal diameter +is 191/2 feet, and the dome is 8 inches in thickness and has a radius of +161/2 feet. It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of relatively +small bulk--a bad feature as regards resistance to shock. To obviate +this difficulty, the inventor partitions it internally in such a way as +to leave only sufficient space to maneuver the guns. The partitions +consist of iron plate boxes filled with concrete. The form of the dome +has one inconvenience, viz., the embrasure in it is necessarily very +oblique, and offers quite an elongated ellipse to blows, and the edges +of the bevel upon a portion of the circumference are not strong enough. +In order to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides of +the embrasure. The motion of the piece necessary to aim it vertically is +effected around this axis of rotation. The weight of the gun is balanced +by a system of counterpoises and the chains, l, and the breech +terminates in a hollow screw, f, and a nut, g, held between two +directing sectors, h. The cupola is revolved by simply acting upon the +rollers. + +[Illustration: FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.] + +_Mougin's Rolled Iron Cupola_.--The general form of this cupola (Fig. 1) +is that of a cylindrical turret. It is 123/4 feet in diameter, and rises +31/4 feet above the top of the glacis. It has an advantage over the one +just described in possessing more internal space, without having so +large a diameter; and, as the embrasures are at right angles with the +sides, the plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of strong +iron plate strengthened by angle irons. Vertical partitions under the +cheeks of the gun carriages serve as cross braces, and are connected +with each other upon the table of the hydraulic pivot around which the +entire affair revolves. This pivot terminates in a plunger that enters a +strong steel press-cylinder embedded in the masonry of the lower +concrete vault. + +The iron plate ring carries wheels and rollers, through the intermedium +of which the turret is revolved. The circular iron track over which +these move is independent of the outer armor. + +The whole is maneuvered through the action of one man upon the piston of +a very small hydraulic press. The guns are mounted upon hydraulic +carriages. The brake that limits the recoil consists of two bronze pump +chambers, a and b (Fig. 10). The former of these is 4 inches in +diameter, and its piston is connected with the gun, while the other is 8 +inches in diameter, and its piston is connected with two rows of 26 +couples of Belleville springs, d. The two cylinders communicate through +a check valve. + +When the gun is in battery, the liquid fills the chamber of the 4 inch +pump, while the piston of the 8 inch one is at the end of its stroke. A +recoil has the effect of driving in the 4 inch piston and forcing the +liquid into the other chamber, whose piston compresses the springs. At +the end of the recoil, the gunner has only to act upon the valve by +means of a hand-wheel in order to bring the gun into battery as slowly +as he desires, through the action of the springs. + +[Illustration: FIG. 10.--MOUGIN'S HYDRAULIC GUN CARRIAGE.] + +For high aiming, the gun and the movable part of its carriage are +capable of revolving around a strong pin, c, so placed that the axis of +the piece always passes very near the center of the embrasure, thus +permitting of giving the latter minimum dimensions. The chamber of the 8 +inch pump is provided with projections that slide between circular +guides, and carries the strap of a small hydraulic piston, p, that +suffices to move the entire affair in a vertical plane, the gun and +movable carriage being balanced by a counterpoise, q. + +The projectiles are hoisted to the breech of the gun by a crane. + +Between the outer armor and turret sufficient space is left for a man to +enter, in order to make repairs when necessary. + +Each of the rolled iron plates of which the turret consists weighs 19 +tons. The cupolas that we have examined in this article have been +constructed on the hypothesis than an enemy will not be able to bring +into the field guns of much greater caliber than 6 inches.--_Le Genie +Civil_. + + * * * * * + + + + +HIGH SPEED ON THE OCEAN. + + +_To the Editor of the Scientific American_: + +Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN of +Jan. 2, 1886, in regard to high speed on the ocean. + +Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the plane +of their motion, but at an angle to it, the same principle would, if +applied to a steamship, increase its speed. But let us look at the +subject from another standpoint. The quadruped has to support the weight +of his body, and propel himself forward, with the same force. If the +force be applied perpendicularly, the body is elevated, but not moved +forward. If the force is applied horizontally, the body moves forward, +but soon falls to the ground, because it is not supported. But when the +force is applied at the proper angle, the body is moved forward and at +the same time supported. Directly contrary to Capt. Giles' theory, the +greater the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and _vice versa_. This may +easily be seen by any one watching the motions of the horse, hound, +deer, rabbit, etc., when in rapid motion. The water birds and animals, +whose weight is supported by the water, do not exert the propulsive +force in a downward direction, but in a direct line with the plane of +their motion. The man who swims does not increase his motion by kicking +out at an angle, but by drawing the feet together with the legs +straight, thus using the water between them as a double inclined plane, +on which his feet and legs slide and thus increase his motion. The +weight of the steamship is already supported by the water, and all that +is required of the propeller is to push her forward. If set so as to act +in a direct line with the plane of motion, it will use all its force to +push her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. If +placed at an angle of 45 deg. with the plane of motion, half the force will +be used in raising the ship out of the water, and only half will be left +to push her forward. + +ENOS M. RICKER. + +Park Rapids, Minn., Jan. 23, 1886. + + * * * * * + + + + +SIBLEY COLLEGE LECTURES. + +BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING. + + + + +PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING BODIES. + +BY CHAS. T. PORTER. + +INTRODUCTION. + + +On appearing for the first time before this Association, which, as I am +informed, comprises the faculty and the entire body of students of the +Sibley College of Mechanical Engineering and the Mechanic Arts, a +reminiscence of the founder of this College suggests itself to me, in +the relation of which I beg first to be indulged. + +In the years 1847-8-9 I lived in Rochester, N.Y., and formed a slight +acquaintance with Mr. Sibley, whose home was then, as it has ever since +been, in that city. Nearly twelve years afterward, in the summer of +1861, which will be remembered as the first year of our civil war, I met +Mr. Sibley again. We happened to occupy a seat together in a car from +New York to Albany. He recollected me, and we had a conversation which +made a lasting impression on my memory. I said we had a conversation. +That reminds me of a story told by my dear friend, of precious memory, +Alexander L. Holley. One summer Mr. Holley accompanied a party of +artists on an excursion to Mt. Katahdin, which, as you know, rises in +almost solitary grandeur amid the forests and lakes of Maine. He wrote, +in his inimitably happy style, an account of this excursion, which +appeared some time after in _Scribner's Monthly_, elegantly illustrated +with views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. Katahdin. +"That is," he explained, "Mr. Church painted, and I held the umbrella." + +This describes the conversation which Mr. Sibley and I had. Mr. Sibley +talked, and I listened. He was a good talker, and I flatter myself that +I rather excel as a listener. On that occasion I did my best, for I knew +whom I was listening to. I was listening to the man who combined bold +and comprehensive grasp of thought, unerring foresight and sagacity, and +energy of action and power of accomplishment, in a degree not surpassed, +if it was equaled, among men. + +Some years before, Mr. Sibley had created the Western Union Telegraph +Company. At that time telegraphy was in a very depressed state. The +country was to a considerable extent occupied by local lines, chartered +under various State laws, and operated without concert. Four rival +companies, organized under the Morse, the Bain, the House, and the +Hughes patents, competed for the business. Telegraph stock was nearly +valueless. Hiram Sibley, a man of the people, a resident of an inland +city, of only moderate fortune, alone grasped the situation. He saw that +the nature of the business, and the demands of the country, alike +required that a single organization, in which all interests should be +combined, should cover the entire land with its network, by means of +which every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this vividly, +and realized it with the most intense earnestness of conviction. With +Mr. Sibley, to be convinced was to act; and so he set about the task of +carrying this vast scheme into execution. The result is well known. By +his immense energy, the magnetic power with which he infused his own +convictions into other minds, the direct, practical way in which he set +about the work, and his indomitable perseverance, Mr. Sibley attained at +last a phenomenal success. + +But he was not then telling me anything about this. He was telling me of +the construction of the telegraph line to the Pacific Coast. Here again +Mr. Sibley had seen that which was hidden from others. This case +differed from the former one in two important respects. Then Mr. Sibley +had been dependent on the aid and co-operation of many persons; and this +he had been able to secure. Now, he could not obtain help from a human +being; but he had become able to act independently of any assistance. + +He had made a careful study of the subject, in his thoroughly practical +way, and had become convinced that such a line was feasible, and would +be remunerative. At his instance a convention of telegraph men met in +the city of New York, to consider the project. The feeling in this +convention was extremely unfavorable to it. A committee reported against +it unanimously, on three grounds--the country was destitute of timber, +the line would be destroyed by the Indians, and if constructed and +maintained, it would not pay expenses. Mr. Sibley found himself alone. +An earnest appeal which he made from the report of the committee was +received with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and two +thousand miles of its breadth by bands of savages, who of course would +destroy the line as soon as it was put up, and where repairs would be +difficult and useless, even if the other objections to it were out of +the way, struck the members of the convention as so exquisitely +ludicrous that it seemed as if they would never be done laughing about +it. If Mr. Sibley had advocated a line to the moon, they would hardly +have seen in it greater evidence of lunacy. When he could be heard, he +rose again and said: "Gentlemen, you may laugh, but if I was not so old, +I would build the line myself." Upon this, of course, they laughed +louder than ever. As they laughed, he grew mad, and shouted: "Gentlemen, +I will bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon it +scouted the project as chimerical, and no capitalist would put a dollar +in it, Hiram Sibley built the line of telegraph to San Francisco, +risking in it all he had in the world. He set about the work with his +customary energy, all obstacles vanished, and the line was completed in +an incredibly short time. And from the day it was opened, it has proved +probably the most profitable line of telegraph that has ever been +constructed. There was the practicability, and there was the demand and +the business to be done, and yet no living man could see it, or could be +made to see it, except Hiram Sibley. "And to-day," he said, with honest +pride, "to-day in New York, men to whom I went almost on my knees for +help in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one." + +"But how about the Indians?" I asked. "Why," he replied, "we never had +any trouble from the Indians. I knew we wouldn't have. Men who supposed +I was such a fool as to go about this undertaking before that was all +settled didn't know me. No Indian ever harmed that line. The Indians are +the best friends we have got. You see, we taught the Indians the Great +Spirit was in that line; and what was more, we proved it to them. It +was, by all odds, the greatest medicine they ever saw. They fairly +worshiped it. No Indian ever dared to do it harm." + +"But," he added, "there was one thing I didn't count on. The border +ruffians in Missouri are as bad as anybody ever feared the Indians might +be. They have given us so much trouble that we are now building a line +around that State, through Iowa and Nebraska. We are obliged to do it." + +This opened another phase of the subject. The telegraph line to the +Pacific had a value beyond that which could be expressed in money. It +was perhaps the strongest of all the ties which bound California so +securely to the Union, in the dark days of its struggle for existence. +The secession element in Missouri recognized the importance of the line +in this respect, and were persistent in their efforts to destroy it. We +have seen by what means their purpose was thwarted. + +I have always felt that, among the countless evidences of the ordering +of Providence by which the war for the preservation of the Union was +signalized, not the least striking was the raising up of this remarkable +man, to accomplish alone, and in the very nick of time, a work which at +once became of such national importance. + +This is the man who has crowned his useful career, and shown again his +eminently practical character and wise foresight, by the endowment of +this College, which cannot fail to be a perennial source of benefit to +the country whose interests he has done so much to promote, and which +his remarkable sagacity and energy contributed so much to preserve. + +We have an excellent rule, followed by all successful designers of +machinery, which is, to make provision for the extreme case, for the +most severe test to which, under normal conditions, and so far as +practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than the +extreme demand are not likely to give trouble. I shall apply this +principle in addressing you to-day. In what I have to say, I shall speak +directly to the youngest and least advanced minds among my auditors. If +I am successful in making an exposition of my subject which shall be +plain to them, then it is evident that I need not concern myself about +being understood by the higher class men and the professors. + +The subject to which your attention is now invited is + + +THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES. + +This is a subject with which every one who expects to be concerned with +machinery, either as designer or constructor, ought to be familiar. The +principles which underlie it are very simple, but in order to be of use, +these need to be thoroughly understood. If they have once been mastered, +made familiar, incorporated into your intellectual being, so as to be +readily and naturally applied to every case as it arises, then you +occupy a high vantage ground. In this particular, at least, you will not +go about your work uncertainly, trying first this method and then that +one, or leaving errors to be disclosed when too late to remedy them. On +the contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what you +intend. + +Moreover, when you read discussions on any branch of this subject, you +will not receive these into unprepared minds, just as apt to admit error +as truth, and possessing no test by which to distinguish the one from +the other; but you will be able to form intelligent judgments with +respect to them. You will discover at once whether or not the writers +are anchored to the sure holding ground of sound principles. + +It is to be observed that I do not speak of balancing bodies, but of +balancing forces. Forces are the realities with which, as mechanical +engineers, you will have directly to deal, all through your lives. The +present discussion is limited also to those forces which are developed +in moving bodies, or by the motion of bodies. This limitation excludes +the force of gravity, which acts on all bodies alike, whether at rest or +in motion. It is, indeed, often desirable to neutralize the effect of +gravity on machinery. The methods of doing this are, however, obvious, +and I shall not further refer to them. + +Two very different forces, or manifestations of force, are developed by +the motion of bodies. These are + + +MOMENTUM AND CENTRIFUGAL FORCE. + +The first of these forces is exerted by every moving body, whatever the +nature of the path in which it is moving, and always in the direction of +its motion. The latter force is exerted only by bodies whose path is a +circle, or a curve of some form, about a central body or point, to which +it is held, and this force is always at right angles with the direction +of motion of the body. + +Respecting momentum, I wish only to call your attention to a single +fact, which will become of importance in the course of our discussion. +Experiments on falling bodies, as well as all experience, show that the +velocity of every moving body is the product of two factors, which must +combine to produce it. Those factors are force and distance. In order to +impart motion to the body, force must act through distance. These two +factors may be combined in any proportions whatever. The velocity +imparted to the body will vary as the square root of their product. +Thus, in the case of any given body, + + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. + +This table might be continued indefinitely. The product of the force +into the distance will always vary as the square of the final velocity +imparted. To arrest a given velocity, the same force, acting through the +same distance, or the same product of force into distance, is required +that was required to impart the velocity. + +The fundamental truth which I now wish to impress upon your minds is +that in order to impart velocity to a body, to develop the energy which +is possessed by a body in motion, force must act through distance. +Distance is a factor as essential as force. Infinite force could not +impart to a body the least velocity, could not develop the least energy, +without acting through distance. + +This exposition of the nature of momentum is sufficient for my present +purpose. I shall have occasion to apply it later on, and to describe the +methods of balancing this force, in those cases in which it becomes +necessary or desirable to do so. At present I will proceed to consider +the second of the forces, or manifestations of force, which are +developed in moving bodies--_centrifugal force_. + +This force presents its claims to attention in all bodies which revolve +about fixed centers, and sometimes these claims are presented with a +good deal of urgency. At the same time, there is probably no subject, +about which the ideas of men generally are more vague and confused. This +confusion is directly due to the vague manner in which the subject of +centrifugal force is treated, even by our best writers. As would then +naturally be expected, the definitions of it commonly found in our +handbooks are generally indefinite, or misleading, or even absolutely +untrue. + +Before we can intelligently consider the principles and methods of +balancing this force, we must get a correct conception of the nature of +the force itself. What, then, is centrifugal force? It is an extremely +simple thing; a very ordinary amount of mechanical intelligence is +sufficient to enable one to form a correct and clear idea of it. This +fact renders it all the more surprising that such inaccurate and +confused language should be employed in its definition. Respecting +writers, also, who use language with precision, and who are profound +masters of this subject, it must be said that, if it had been their +purpose to shroud centrifugal force in mystery, they could hardly have +accomplished this purpose more effectually than they have done, to minds +by whom it was not already well understood. + +Let us suppose a body to be moving in a circular path, around a center +to which it is firmly held; and let us, moreover, suppose the impelling +force, by which the body was put in motion, to have ceased; and, also, +that the body encounters no resistance to its motion. It is then, by our +supposition, moving in its circular path with a uniform velocity, +neither accelerated nor retarded. Under these conditions, what is the +force which is being exerted on this body? Clearly, there is only one +such force, and that is, the force which holds it to the center, and +compels it, in its uniform motion, to maintain a fixed distance from +this center. This is what is termed centripetal force. It is obvious, +that the centripetal force, which holds this revolving body _to_ the +center, is the only force which is being exerted upon it. + +Where, then, is the centrifugal force? Why, the fact is, there is not +any such thing. In the dynamical sense of the term "force," the sense in +which this term is always understood in ordinary speech, as something +tending to produce motion, and the direction of which determines the +direction in which motion of a body must take place, there is, I repeat, +no such thing as centrifugal force. + +There is, however, another sense in which the term "force" is employed, +which, in distinction from the above, is termed a statical sense. This +"statical force" is the force by the exertion of which a body keeps +still. It is the force of inertia--the resistance which all matter +opposes to a dynamical force exerted to put it in motion. This is the +sense in which the term "force" is employed in the expression +"centrifugal force." Is that all? you ask. Yes; that is all. + +I must explain to you how it is that a revolving body exerts this +resistance to being put in motion, when all the while it _is_ in motion, +with, according to our above supposition, a uniform velocity. The first +law of motion, so far as we now have occasion to employ it, is that a +body, when put in motion, moves in a straight line. This a moving body +always does, unless it is acted on by some force, other than its +impelling force, which deflects it, or turns it aside, from its direct +line of motion. A familiar example of this deflecting force is afforded +by the force of gravity, as it acts on a projectile. The projectile, +discharged at any angle of elevation, would move on in a straight line +forever, but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made to +fall, by the attraction of the earth; and so instead of a straight line +it describes a curve, known as the trajectory. + +Now a revolving body, also, has the same tendency to move in a straight +line. It would do so, if it were not continually deflected from this +line. Another force is constantly exerted upon it, compelling it, at +every successive point of its path, to leave the direct line of motion, +and move on a line which is everywhere equally distant from the center +to which it is held. If at any point the revolving body could get free, +and sometimes it does get free, it would move straight on, in a line +tangent to the circle at the point of its liberation. But if it cannot +get free, it is compelled to leave each new tangential direction, as +soon as it has taken it. + +This is illustrated in the above figure. The body, A, is supposed to be +revolving in the direction indicated by the arrow, in the circle, A B F +G, around the center, O, to which it is held by the cord, O A. At the +point, A, it is moving in the tangential direction, A D. It would +continue to move in this direction, did not the cord, O A, compel it to +move in the arc, A C. Should this cord break at the point, A, the body +would move; straight on toward D, with whatever velocity it had. + +You perceive now what centrifugal force is. This body is moving in the +direction, A D. The centripetal force, exerted through the cord, O A, +pulls it aside from this direction of motion. The body resists this +deflection, and this resistance is its centrifugal force. + +[Illustration: Fig. 1] + +Centrifugal force is, then, properly defined to be the disposition of a +revolving body to move in a straight line, and the resistance which such +a body opposes to being drawn aside from a straight line of motion. The +force which draws the revolving body continually to the center, or the +deflecting force, is called the centripetal force, and, aside from the +impelling and retarding forces which act in the direction of its motion, +the centripetal force is, dynamically speaking, the only force which is +exerted on the body. + +It is true, the resistance of the body furnishes the measure of the +centripetal force. That is, the centripetal force must be exerted in a +degree sufficient to overcome this resistance, if the body is to move in +the circular path. In this respect, however, this case does not differ +from every other case of the exertion of force. Force is always exerted +to overcome resistance: otherwise it could not be exerted. And the +resistance always furnishes the exact measure of the force. I wish to +make it entirely clear, that in the dynamical sense of the term "force," +there is no such thing as centrifugal force. The dynamical force, that +which produces motion, is the centripetal force, drawing the body +continually from the tangential direction, toward the center; and what +is termed centrifugal force is merely the resistance which the body +opposes to this deflection, _precisely like any other resistance to a +force_. + +The centripetal force is exerted on the radial line, as on the line, A +O, Fig. 1, at right angles with the direction in which the body is +moving; and draws it directly toward the center. It is, therefore, +necessary that the resistance to this force shall also be exerted on the +same line, in the opposite direction, or directly from the center. But +this resistance has not the least power or tendency to produce motion in +the direction in which it is exerted, any more than any other resistance +has. + +We have been supposing a body to be firmly held to the center, so as to +be compelled to revolve about it in a fixed path. But the bond which +holds it to the center may be elastic, and in that case, if the +centrifugal force is sufficient, the body will be drawn from the center, +stretching the elastic bond. It may be asked if this does not show +centrifugal force to be a force tending to produce motion from the +center. This question is answered by describing the action which really +takes place. The revolving body is now imperfectly deflected. The bond +is not strong enough to compel it to leave its direct line of motion, +and so it advances a certain distance along this tangential line. This +advance brings the body into a larger circle, and by this enlargement of +the circle, assuming the rate of revolution to be maintained, its +centrifugal force is proportionately increased. The deflecting power +exerted by the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct path; +and when the limit of its elasticity is reached, the deflecting bond +will be broken. If, however, the strength of the deflecting bond is +increased by its elongation in a more rapid ratio than the centrifugal +force is increased by the enlargement of the circle, then a point will +be reached in which the centripetal force will be sufficient to compel +the body to move again in the circular path. + +Sometimes the centripetal force is weak, and opportunity is afforded to +observe this action, and see its character exhibited. A common example +of weak centripetal force is the adhesion of water to the face of a +revolving grindstone. Here we see the deflecting force to become +insufficient to compel the drops of water longer to leave their direct +paths, and so these do not longer leave their direct paths, but move on +in those paths, with the velocity they have at the instant of leaving +the stone, flying off on tangential lines. + +If, however, a fluid be poured on the side of the revolving wheel near +the axis, it will move out to the rim on radial lines, as may be +observed on car wheels universally. The radial lines of black oil on +these wheels look very much as if centrifugal force actually did produce +motion, or had at least a very decided tendency to produce motion, in +the radial direction. This interesting action calls for explanation. In +this action the oil moves outward gradually, or by inconceivably minute +steps. Its adhesion being overcome in the least possible degree, it +moves in the same degree tangentially. In so doing it comes in contact +with a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it had +overcome the adhesion. Motion in the radial direction is the result of +these two actions, namely, leaving the first point of contact +tangentially and receiving an acceleration of its motion, so that this +shall be equal to that of the second point of contact. When we think +about the matter a little closely, we see that at the rim of the wheel +the oil has perhaps ten times the velocity of revolution which it had on +leaving the journal, and that the mystery to be explained really is, How +did it get that velocity, moving out on a radial line? Why was it not +left behind at the very first? Solely by reason of its forward +tangential motion. That is the answer. + +When writers who understand the subject talk about the centripetal and +centrifugal forces being different names for the same force, and about +equal action and reaction, and employ other confusing expressions, just +remember that all they really mean is to express the universal relation +between force and resistance. The expression "centrifugal force" is +itself so misleading, that it becomes especially important that the real +nature of this so-called force, or the sense in which the term "force" +is used in this expression, should be fully explained.[1] This force is +now seen to be merely the tendency of a revolving body to move in a +straight line, and the resistance which it opposes to being drawn aside +from that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see. + +[Footnote 1: I was led to study this subject in looking to see what had +become of my first permanent investment, a small venture, made about +thirty-five years ago, in the "Sawyer and Gwynne static pressure +engine." This was the high-sounding name of the Keely motor of that day, +an imposition made possible by the confused ideas prevalent on this very +subject of centrifugal force.] + +FIRST.--I have called your attention to the fact that the direction in +which the revolving body is deflected from the tangential line of motion +is toward the center, on the radial line, which forms a right angle with +the tangent on which the body is moving. The first question that +presents itself is this: What is the measure or amount of this +deflection? The answer is, this measure or amount is the versed sine of +the angle through which the body moves. + +Now, I suspect that some of you--some of those whom I am directly +addressing--may not know what the versed sine of an angle is; so I must +tell you. We will refer again to Fig. 1. In this figure, O A is one +radius of the circle in which the body A is revolving. O C is another +radius of this circle. These two radii include between them the angle A +O C. This angle is subtended by the arc A C. If from the point O we let +fall the line C E perpendicular to the radius O A, this line will divide +the radius O A into two parts, O E and E A. Now we have the three +interior lines, or the three lines within the circle, which are +fundamental in trigonometry. C E is the sine, O E is the cosine, and E A +is the versed sine of the angle A O C. Respecting these three lines +there are many things to be observed. I will call your attention to the +following only: + +_First_.--Their length is always less than the radius. The radius is +expressed by 1, or unity. So, these lines being less than unity, their +length is always expressed by decimals, which mean equal to such a +proportion of the radius. + +_Second_.--The cosine and the versed sine are together equal to the +radius, so that the versed sine is always 1, less the cosine. + +_Third_.--If I diminish the angle A O C, by moving the radius O C toward +O A, the sine C E diminishes rapidly, and the versed sine E A also +diminishes, but more slowly, while the cosine O E increases. This you +will see represented in the smaller angles shown in Fig. 2. If, finally, +I make O C to coincide with O A, the angle is obliterated, the sine and +the versed sine have both disappeared, and the cosine has become the +radius. + +_Fourth_.--If, on the contrary, I enlarge the angle A O C by moving the +radius O C toward O B, then the sine and the versed sine both increase, +and the cosine diminishes; and if, finally, I make O C coincide with O +B, then the cosine has disappeared, the sine has become the radius O B, +and the versed sine has become the radius O A, thus forming the two +sides inclosing the right angle A O B. The study of this explanation +will make you familiar with these important lines. The sine and the +cosine I shall have occasion to employ in the latter part of my lecture. +Now you know what the versed sine of an angle is, and are able to +observe in Fig. 1 that the versed sine A E, of the angle A O C, +represents in a general way the distance that the body A will be +deflected from the tangent A D toward the center O while describing the +arc A C. + +The same law of deflection is shown, in smaller angles, in Fig. 2. In +this figure, also, you observe in each of the angles A O B and A O C +that the deflection, from the tangential direction toward the center, of +a body moving in the arc A C is represented by the versed sine of the +angle. The tangent to the arc at A, from which this deflection is +measured, is omitted in this figure to avoid confusion. It is shown +sufficiently in Fig. 1. The angles in Fig. 2 are still pretty large +angles, being 12 deg. and 24 deg. respectively. These large angles are used for +convenience of illustration; but it should be explained that this law +does not really hold in them, as is evident, because the arc is longer +than the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent and +arc coincide, and approximately so for exceedingly small angles. + +[Illustration: Fig. 2] + +In reality, however, we have only to do with the case in which the arc +and the tangent do coincide, and in which the law that the deflection is +_equal to_ the versed sine of the angle is absolutely true. Here, in +observing this most familiar thing, we are, at a single step, taken to +that which is utterly beyond our comprehension. The angles we have to +consider disappear, not only from our sight, but even from our +conception. As in every other case when we push a physical investigation +to its limit, so here also, we find our power of thought transcended, +and ourselves in the presence of the infinite. + +We can discuss very small angles. We talk familiarly about the angle +which is subtended by 1" of arc. On Fig. 2, a short line is drawn near +to the radius O A'. The distance between O A' and this short line is 1 deg. +of the arc A' B'. If we divide this distance by 3,600, we get 1" of arc. +The upper line of the Table of versed sines given below is the versed +sine of 1" of arc. It takes 1,296,000 of these angles to fill a circular +space. These are a great many angles, but they do not make a circle. +They make a polygon. If the radius of the circumscribed circle of this +polygon is 1,296,000 feet, which is nearly 213 geographical miles, each +one of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon would be +one-sixtieth of a geographical mile, or 101.46 feet. On the orbit of the +moon, at its mean distance from the earth, each of these straight sides +would be about 6,000 feet long. + +The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never can +reach the circle. When you swing a sling around your head, and feel the +uniform stress exerted on your hand through the cord, you are made aware +of an action which is entirely beyond the grasp of our minds and the +reach of our analysis. + +So always in practical operation that law is absolutely true which we +observe to be approximated to more and more nearly as we consider +smaller and smaller angles, that the versed sine of the angle is the +measure of its deflection from the straight line of motion, or the +measure of its fall toward the center, which takes place at every point +in the motion of a revolving body. + +Then, assuming the absolute truth of this law of deflection, we find +ourselves able to explain all the phenomena of centrifugal force, and to +compute its amount correctly in all cases. + +We have now advanced two steps. We have learned _the direction_ and _the +measure_ of the deflection, which a revolving body continually suffers, +and its resistance to which is termed centrifugal force. The direction +is toward the center, and the measure is the versed sine of the angle. + +SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that the +amount of centrifugal force exerted by a revolving body varies in four +ways. + +_First_.--Directly as the weight of the body. + +_Second_.--In a given circle of revolution, as the square of the speed +or of the number of revolutions per minute; which two expressions in +this case mean the same thing. + +_Third_.--With a given number of revolutions per minute, or a given +angular velocity[1] _directly_ as the radius of the circle; and + +_Fourth_.--With a given actual velocity, or speed in feet per minute, +_inversely_ as the radius of the circle. + +[Footnote 1: A revolving body is said to have the same angular velocity, +when it sweeps through equal angles in equal times. Its actual velocity +varies directly as the radius of the circle in which it is revolving.] + +Of course there is a reason for these laws. You are not to learn them by +rote, or to accept them on any authority. You are taught not to accept +any rule or formula on authority, but to demand the reason for it--to +give yourselves no rest until you know the why and wherefore, and +comprehend these fully. This is education, not cramming the mind with +mere facts and rules to be memorized, but drawing out the mental powers +into activity, strengthening them by use and exercise, and forming the +habit, and at the same time developing the power, of penetrating to the +reason of things. + +In this way only, you will be able to meet the requirement of a great +educator, who said: "I do not care to be told what a young man knows, +but what he can _do_." I wish here to add my grain to the weight of +instruction which you receive, line upon line, precept on precept, on +this subject. + +The reason for these laws of centrifugal force is an extremely simple +one. The first law, that this force varies directly as the weight of the +body, is of course obvious. We need not refer to this law any further. +The second, third, and fourth laws merely express the relative rates at +which a revolving body is deflected from the tangential direction of +motion, in each of the three cases described, and which cases embrace +all possible conditions. + +These three rates of deflection are exhibited in Fig. 2. An examination +of this figure will give you a clear understanding of them. Let us first +suppose a body to be revolving about the point, O, as a center, in a +circle of which A B C is an arc, and with a velocity which will carry it +from A to B in one second of time. Then in this time the body is +deflected from the tangential direction a distance equal to A D, the +versed sine of the angle A O B. Now let us suppose the velocity of this +body to be doubled in the same circle. In one second of time it moves +from A to C, and is deflected from the tangential direction of motion a +distance equal to A E, the versed sine of the angle, A O C. But A E is +four times A D. Here we see in a given circle of revolution the +deflection varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded. + +The following table will show, by comparison of the versed sines of very +small angles, the deflection in a given circle varying as the square of +the speed, when we penetrate to them, so nearly that the error is not +disclosed at the fifteenth place of decimals. + + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 + +You observe the deflection for 10" of arc is 100 times as great, and for +100" of arc is 10,000 times as great as it is for 1" of arc. So far as +is shown by the 15th place of decimals, the versed sine varies as the +square of the angle; or, in a given circle, the deflection, and so the +centrifugal force, of a revolving body varies as the square of the +speed. + +The reason for the third law is equally apparent on inspection of Fig. +2. It is obvious, that in the case of bodies making the same number of +revolutions in different circles, the deflection must vary directly as +the diameter of the circle, because for any given angle the versed sine +varies directly as the radius. Thus radius O A' is twice radius O A, and +so the versed sine of the arc A' B' is twice the versed sine of the arc +A B. Here, while the angular velocity is the same, the actual velocity +is doubled by increase in the diameter of the circle, and so the +deflection is doubled. This exhibits the general law, that with a given +angular velocity the centrifugal force varies directly as the radius or +diameter of the circle. + +We come now to the reason for the fourth law, that, with a given actual +velocity, the centrifugal force varies _inversely_ as the diameter of +the circle. If any of you ever revolved a weight at the end of a cord +with some velocity, and let the cord wind up, suppose around your hand, +without doing anything to accelerate the motion, then, while the circle +of revolution was growing smaller, the actual velocity continuing nearly +uniform, you have felt the continually increasing stress, and have +observed the increasing angular velocity, the two obviously increasing +in the same ratio. That is the operation or action which the fourth law +of centrifugal force expresses. An examination of this same figure (Fig. +2) will show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. If we +take the velocity A' B', double the velocity A B, and transfer it to the +smaller circle, we have the velocity A C. But the deflection has been +increasing as we have reduced the circle, and now with one half the +radius it is twice as great. It has increased in the same ratio in which +the angular velocity has increased. Thus we see the simple and necessary +nature of these laws. They merely express the different rates of +deflection of a revolving body in these different cases. + +THIRD.--We have a coefficient of centrifugal force, by which we are +enabled to compute the amount of this resistance of a revolving body to +deflection from a direct line of motion in all cases. This is that +coefficient. The centrifugal force of a body making _one_ revolution per +minute, in a circle of _one_ foot radius, is 0.000341 of the weight of +the body. + +According to the above laws, we have only to multiply this coefficient +by the square of the number of revolutions made by the body per minute, +and this product by the radius of the circle in feet, or in decimals of +a foot, and we have the centrifugal force, in terms of the weight of the +body. Multiplying this by the weight of the body in pounds, we have the +centrifugal force in pounds. + +Of course you want to know how this coefficient has been found out, and +how you can be sure it is correct. I will tell you a very simple way. +There are also mathematical methods of ascertaining this coefficient, +which your professors, if you ask them, will let you dig out for +yourselves. The way I am going to tell you I found out for myself, and +that, I assure you, is the only way to learn anything, so that it will +stick; and the more trouble the search gives you, the darker the way +seems, and the greater the degree of perseverance that is demanded, the +more you will appreciate the truth when you have found it, and the more +complete and permanent your possession of it will be. + +The explanation of this method may be a little more abstruse than the +explanations already given, but it is very simple and elegant when you +see it, and I fancy I can make it quite clear. I shall have to preface +it by the explanation of two simple laws. The first of these is, that a +body acted on by a constant force, so as to have its motion uniformly +accelerated, suppose in a straight line, moves through distances which +increase as the square of the time that the accelerating force continues +to be exerted. + +The necessary nature of this law, or rather the action of which this law +is the expression, is shown in Fig. 3. + +[Illustration: Fig. 3] + +Let the distances A B, B C, C D, and D E in this figure represent four +successive seconds of time. They may just as well be conceived to +represent any other equal units, however small. Seconds are taken only +for convenience. At the commencement of the first second, let a body +start from a state of rest at A, under the action of a constant force, +sufficient to move it in one second through a distance of one foot. This +distance also is taken only for convenience. At the end of this second, +the body will have acquired a velocity of two feet per second. This is +obvious because, in order to move through one foot in this second, the +body must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. Its +motion increased uniformly. Therefore, at the termination of the second +its velocity must have reached two feet per second. Let the triangle A B +F represent this accelerated motion, and the distance, of one foot, +moved through during the first second, and let the line B F represent +the velocity of two feet per second, acquired by the body at the end of +it. Now let us imagine the action of the accelerating force suddenly to +cease, and the body to move on merely with the velocity it has acquired. +During the next second it will move through two feet, as represented by +the square B F C I. But in fact, the action of the accelerating force +does not cease. This force continues to be exerted, and produces on the +body during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity accelerated +two additional feet per second, as represented by the line I G. So in +two seconds the body has moved through four feet. We may follow the +operation of this law as far as we choose. The figure shows it during +four seconds, or any other unit, of time, and also for any unit of +distance. Thus: + + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 + +So it is obvious that the distance moved through by a body whose motion +is uniformly accelerated increases as the square of the time. + +But, you are asking, what has all this to do with a revolving body? As +soon as your minds can be started from a state of rest, you will +perceive that it has everything to do with a revolving body. The +centripetal force, which acts upon a revolving body to draw it to the +center, is a constant force, and under it the revolving body must move +or be deflected through distances which increase as the squares of the +times, just as any body must do when acted on by a constant force. To +prove that a revolving body obeys this law, I have only to draw your +attention to Fig. 2. Let the equal arcs, A B and B C, in this figure +represent now equal times, as they will do in case of a body revolving +in this circle with a uniform velocity. The versed sines of the angles, +A O B and A O C, show that in the time, A C, the revolving body was +deflected four times as far from the tangent to the circle at A as it +was in the time, A B. So the deflection increased as the square of the +time. If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute angles, +absolutely so far as appears up to the fifteenth place of decimals, as +the square of the time. + +The standard from which all computations are made of the distances +passed through in given times by bodies whose motion is uniformly +accelerated, and from which the velocity acquired is computed when the +accelerating force is known, and the force is found when the velocity +acquired or the rate of acceleration is known, is the velocity of a body +falling to the earth. It has been established by experiment, that in +this latitude near the level of the sea, a falling body in one second +falls through a distance of 16.083 feet, and acquires a velocity of +32.166 feet per second; or, rather, that it would do so if it did not +meet the resistance of the atmosphere. In the case of a falling body, +its weight furnishes, first, the inertia, or the resistance to motion, +that has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the earth, or +the force exerted to overcome its resistance. Here, as in all possible +cases, the force and the resistance are identical with each other. The +above is, therefore, found in this way to be the rate at which the +motion of any body will be accelerated when it is acted on by a constant +force equal to its weight, and encounters no resistance. + +It follows that a revolving body, when moving uniformly in any circle at +a speed at which its deflection from a straight line of motion is such +that in one second this would amount to 16.083 feet, requires the +exertion of a centripetal force equal to its weight to produce such +deflection. The deflection varying as the square of the time, in 0.01 of +a second this deflection will be through a distance of 0.0016083 of a +foot. + +Now, at what speed must a body revolve, in a circle of one foot radius, +in order that in 0.01 of one second of time its deflection from a +tangential direction shall be 0.0016083 of a foot? This decimal is the +versed sine of the arc of 3 deg.15', or of 3.25 deg.. This angle is so small +that the departure from the law that the deflection is equal to the +versed sine of the angle is too slight to appear in our computation. +Therefore, the arc of 3.25 deg. is the arc of a circle of one foot radius +through which a body must revolve in 0.01 of a second of time, in order +that the centripetal force, and so the centrifugal force, shall be equal +to its weight. At this rate of revolution, in one second the body will +revolve through 325 deg., which is at the rate of 54.166 revolutions per +minute. + +Now there remains only one question more to be answered. If at 54.166 +revolutions per minute the centrifugal force of a body is equal to its +weight, what will its centrifugal force be at one revolution per minute +in the same circle? + +To answer this question we have to employ the other extremely simple +law, which I said I must explain to you. It is this: The acceleration +and the force vary in a constant ratio with each other. Thus, let force +1 produce acceleration 1, then force 1 applied again will produce +acceleration 1 again, or, in other words, force 2 will produce +acceleration 2, and so on. This being so, and the amount of the +deflection varying as the squares of the speeds in the two cases, the +centrifugal force of a body making one revolution per minute in a circle +of + + 1 squared + one foot radius will be ---------- = 0.000341 + 54.166 squared + +--the coefficient of centrifugal force. + +There is another mode of making this computation, which is rather neater +and more expeditious than the above. A body making one revolution per +minute in a circle of one foot radius will in one second revolve through +an arc of 6 deg.. The versed sine of this arc of 6 deg. is 0.0054781046 of a +foot. This is, therefore, the distance through which a body revolving at +this rate will be deflected in one second. If it were acted on by a +force equal to its weight, it would be deflected through the distance of +16.083 feet in the same time. What is the deflecting force actually +exerted upon it? Of + + 0.0054781046 +course, it is ------------. + 16.083 + +This division gives 0.000341 of its weight as such deflecting force, the +same as before. + +In taking the versed sine of 6 deg., a minute error is involved, though not +one large enough to change the last figure in the above quotient. The +law of uniform acceleration does not quite hold when we come to an angle +so large as 6 deg.. If closer accuracy is demanded, we can attain it, by +taking the versed sine for 1 deg., and multiplying this by 6 squared. This gives as +a product 0.0054829728, which is a little larger than the versed sine of +6 deg.. + +I hope I have now kept my promise, and made it clear how the coefficient +of centrifugal force may be found in this simple way. + +We have now learned several things about centrifugal force. Let me +recapitulate. We have learned: + +1st. The real nature of centrifugal force. That in the dynamical sense +of the term force, this is not a force at all: that it is not capable of +producing motion, that the force which is really exerted on a revolving +body is the centripetal force, and what we are taught to call +centrifugal force is nothing but the resistance which a revolving body +opposes to this force, precisely like any other resistance. + +2d. The direction of the deflection, to which the centrifugal force is +the resistance, which is straight to the center. + +3d. The measure of this deflection; the versed sine of the angle. + +4th. The reason of the laws of centrifugal force; that these laws merely +express the relative amount of the deflection, and so the amount of the +force required to produce the deflection, and of the resistance of the +revolving body to it, in all different cases. + +5th. That the deflection of a revolving body presents a case analogous +to that of uniformly accelerated motion, under the action of a constant +force, similar to that which is presented by falling bodies;[1] and +finally, + +6th. How to find the coefficient, by which the amount of centrifugal +force exerted in any case may be computed. + +[Footnote 1: A body revolving with a uniform velocity in a horizontal +plane would present the only case of uniformly accelerated motion that +is possible to be realized under actual conditions.] + +I now pass to some other features. + +_First_.--You will observe that, relatively to the center, a revolving +body, at any point in its revolution, is at rest. That is, it has no +motion, either from or toward the center, except that which is produced +by the action of the centripetal force. It has, therefore, this identity +also with a falling body, that it starts from a state of rest. This +brings us to a far more comprehensive definition of centrifugal force. +This is the resistance which a body opposes to being put in motion, at +any velocity acquired in any time, from a state of rest. Thus +centrifugal force reveals to us the measure of the inertia of matter. +This inertia may be demonstrated and exhibited by means of apparatus +constructed on this principle quite as accurately as it can be in any +other way. + +_Second_.--You will also observe the fact, that motion must be imparted +to a body gradually. As distance, _through_ which force can act, is +necessary to the impartation of velocity, so also time, _during_ which +force can act, is necessary to the same result. We do not know how +motion from a state of rest begins, any more than we know how a polygon +becomes a circle. But we do know that infinite force cannot impart +absolutely instantaneous motion to even the smallest body, or to a body +capable of opposing the least resistance. Time being an essential +element or factor in the impartation of velocity, if this factor be +omitted, the least resistance becomes infinite. + +We have a practical illustration of this truth in the explosion of +nitro-glycerine. If a small portion of this compound be exploded on the +surface of a granite bowlder, in the open air, the bowlder will be rent +into fragments. The explanation of this phenomenon common among the +laborers who are the most numerous witnesses of it, which you have +doubtless often heard, and which is accepted by ignorant minds without +further thought, is that the action of nitro-glycerine is downward. We +know that such an idea is absurd. + +The explosive force must be exerted in all directions equally. The real +explanation is, that the explosive action of nitro-glycerine is so +nearly instantaneous, that the resistance of the atmosphere is very +nearly equal to that of the rock; at any rate, is sufficient to cause +the rock to be broken up. The rock yields to the force very nearly as +readily as the atmosphere does. + +_Third_. An interesting solution is presented here of what is to many an +astronomical puzzle. When I was younger than I am now, I was greatly +troubled to understand how it could be that if the moon was always +falling to the earth, as the astronomers assured us it was, it should +never reach it, nor have its falling velocity accelerated. In popular +treatises on astronomy, such for example as that of Professor Newcomb, +this is explained by a diagram in which the tangential line is carried +out as in Fig. 1, and by showing that in falling from the point A to the +earth as a center, through distances increasing as the square of the +time, the moon, having the tangential velocity that it has, could never +get nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this long +tangential line has nothing to do with the motion of the moon, and while +we are compelled to assent to the demonstration, we want something +better. To my mind the better and more satisfactory explanation is found +in the fact that the moon is forever commencing to fall, and is +continually beginning to fall in a new direction. A revolving body, as +we have seen, never gets past that point, which is entirely beyond our +sight and our comprehension, of beginning to fall, before the direction +of its fall is changed. So, under the attraction of the earth, the moon +is forever leaving a new tangential direction of motion at the same +rate, without acceleration. + +(_To be continued_.) + + * * * * * + + + + +COMPRESSED AIR POWER SCHEMES. + +By J. STURGEON, Engineer of the Birmingham Compressed Air Power Company. + + +In the article on "Gas, Air, and Water Power" in the _Journal_ for Dec. +8 last, you state that you await with some curiosity my reply to certain +points in reference to the compressed air power schemes alluded to in +that article. I now, therefore, take the liberty of submitting to you +the arguments on my side of the question (which are substantially the +same as those I am submitting to Mr. Hewson, the Borough Engineer of +Leeds). The details and estimates for the Leeds scheme are not yet in a +forward enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system in +other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters of +detail. We have, however, recently succeeded in obtaining a suitable +place, and making arrangements for railway siding, water supply, etc.; +and we hope to be in a position to start early in the present year. + +I inclose (1) a tabulated summary of the estimates for Birmingham +divided into stages of 3,000 gross indicated horse power at a time; (2) +a statement showing the cost to consumers in terms of indicated horse +power and in different modes, more or less economical, of applying the +air power in the consumers' engines; (3) a tracing showing the method of +laying the mains; (4) a tracing showing the method of collecting the +meter records at the central station, by means of electric apparatus, +and ascertaining the exact amount of leakage. A short description of the +two latter would be as well. + +TABLE I.--_Showing the Progressive Development of the Compressed Air +System in stages of 3000 Indicated Horse Power (gross) at a Time, and +the Profits at each Stage_ + +_____________________________________________________________________________ + +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- + +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- + +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| L12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | L25,595 | L25,595 | L25,595 | L25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | L82,455 | L124,714 | L167,094 | L209,455 | L251,795 | +----------------------------------------------------------------------------- + +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| L6,405 | L7,855 | L9,305 | L10,955 | L12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | L12,080 | L18,508 | L24,944 | L31,589 | L38,096 | +----------------------------------------------------------------------------- + +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- + +TABLE II.--_Cost of Air Power in Terms of Indicated Horse Power_. + +Abbreviated column headings: + +Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per +Hour. + +Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet. + +Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per +Cent. + +Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet. + +Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per +Cent. + +Abbreviated row headings: + +CASE 1.--Where air at 45 lbs. pressure is re-heated to 320 deg. Fahr., and +expanded to atmospheric pressure. + +CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to +212 deg. Fahr., and expanded to atmospheric pressure. + +CASE 3.--Where air is used expansively without re-heating, whereby +intensely cold air is exhausted, and may be used for ice making, &c. + +CASE 4.--Where air is heated to 212 deg. Fahr., and the terminal pressure is +11.3 lbs. above that of the atmosphere + +CASE 5.--Where the air is used without heating, and cut off at one-third +of the stroke, as in ordinary slide-valve engines + +CASE 6.--Where the air is used without re-heating and without expansion. + + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | L s. d. | L s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 01/2| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 51/2 | 9 10 51/2| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 51/2 | 9 1 101/2| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ + +The great thing to guard against is leakage. If the pipes were simply +buried in the ground, it would be almost impossible to trace leakage, or +even to know of its existence. The income of the company might be +wasting away, and the loss never suspected until the quarterly returns +from the meters were obtained from the inspectors. Only then would it be +discovered that there must be a great leak (or it might be several +leaks) somewhere. But how would it be possible to trace them among 20 or +30 miles of buried pipes? We cannot break up the public streets. The +very existence of the concern depends upon (1) the _daily_ checking of +the meter returns, and comparison with the output from the air +compressors, so as to ascertain the amount of leakage; (2) facility for +tracing the locality of a leak; and (3) easy access to the mains with +the minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the pipes +are laid in concrete troughs, near the surface of the road, with +removable concrete covers strong enough to stand any overhead traffic. +At intervals there are junctions for service connections, with street +boxes and covers serving as inspection chambers. These chambers are also +provided over the ball-valves, which serve as stop-valves in case of +necessity, and are so arranged that in case of a serious breach in the +portion of main between any two of them, the rush of air to the breach +will blow them up to the corresponding seats and block off the broken +portion of main. The air space around the pipe in the concrete trough +will convey for a long distance the whistling noise of a leak; and the +inspectors, by listening at the inspection openings, will thus be +enabled to rapidly trace their way almost to the exact spot where there +is an escape. They have then only to remove the top surface of road +metal and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring from +the nearest street opening, the inspectors would know where to break +open the road to arrive at the probable locality of the leak. A very +slight leak can be heard a long way off by its peculiar whistling sound. + +[Illustration: COMPRESSED AIR POWER] + +The next point is to obtain a daily report of the condition of the mains +and the amount of leakage. It would be impracticable to employ an army +of meter inspectors to take the records daily from all the meters in the +district. We therefore adopt the method of electric signaling shown in +the second drawing. In the engineer's office, at the central station, is +fixed the dial shown in Fig. 1. Each consumer's meter is fitted with the +contact-making apparatus shown in Pig. 4, and in an enlarged form in +Figs. 5 and 6, by which a current is sent round the electro-magnet, D +(Fig. 1), attracting the armature, and drawing the disk forward +sufficiently for the roller at I to pass over the center of one of the +pins, and so drop in between that and the next pin, thus completing the +motion, and holding the disk steadily opposite the figure. This action +takes place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose one +meter should be moving very slowly, and so retaining contact for some +time, while other meters were working rapidly; the armature at D would +then be held up to the magnet by the prolonged contact maintained by the +slow moving meter, and so prevent the quick working meters from +actuating it; and they would therefore pass the contact points without +recording. A meter might also stop dead at the point of contact on +shutting off the air, and so hold up the armature; thus preventing +others from acting. To obviate this, we apply the disengaging apparatus +shown at L (Fig. 4). The contact maker works on the center, m, having an +armature on its opposite end. On contact being made, at the same time +that the magnet, D, is operated, the one at L is also operated, +attracting the armature, and throwing over the end of the contact maker, +l, on to the non-conducting side of the pin on the disk. Thus the whole +movement is rendered practically instantaneous, and the magnet at D is +set at liberty for the next operation. A resistance can be interposed at +L, if necessary, to regulate the period of the operation. The whole of +the meters work the common dial shown in Fig. 1, on which the gross +results only are recorded; and this is all we want to know in this way. +The action is so rapid, owing to the use of the magnetic disengaging +gear, that the chances of two or more meters making contact at the same +moment are rendered extremely small. Should such a thing happen, it +would not matter, as it is only approximate results that we require in +this case; and the error, if any, would add to the apparent amount of +leakage, and so be on the right side. Of course, the record of each +consumer's meter would be taken by the inspector at the end of every +quarter, in order to make out the bill; and the totals thus obtained +would be checked by the gross results indicated by the main dial. In +this way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected to an +extremely accurate measurement. At the end of the working day, the +engineer has merely to take down from the dial in his office the total +record of air measured to the consumers, also the output of air from the +compressors, which he ascertains by means of a continuous counter on the +engines, and the difference between the two will represent the loss. If +the loss is trifling, he will pass it over; if serious, he will send out +his inspectors to trace it. Thus there could be no long continued +leakage, misuse, or robbery of the air, without the company becoming +aware of the fact, and so being enabled to take measures to stop or +prevent it. The foregoing are absolutely essential adjuncts to any +scheme of public motive power supply by compressed air, without which we +should be working in the dark, and could never be sure whether the +company were losing or making money. With them, we know where we are and +what we are doing. + +Referring to the estimates given in Table I., I may explain that the +item of repairs and renewals covers 10 per cent. on boilers and gas +producers, 5 per cent. on engines, 5 per cent. on buildings, and 5 per +cent. on mains. Considering that the estimates include ample fitting +shops, with the best and most suitable tools, and that the wages list +includes a staff of men whose chief work would be to attend to repairs, +etc., I think the above allowances ample. Each item also includes 5 per +cent. for contingencies. + +I have commenced by giving all the preceding detail, in order to show +the groundwork on which I base the estimate of the cost of compressed +air power to consumers, in terms of indicated horse power per annum, as +given in Table II. I may say that, in estimating the engine power and +coal consumption, I have not, as in the original report, made purely +theoretical calculations, but have taken diagrams from engines in actual +use (although of somewhat smaller size than those intended to be +employed), and have worked out the results therefrom. It will, I hope, +be seen that, with all the safeguards we have provided, we may fairly +reckon upon having for sale the stated quantity of air produced by means +of the plant, as estimated, and at the specified annual cost; and that +therefore the statement of cost per indicated horse power per annum may +be fairly relied upon. Thus the cost of compressed air to the consumer, +based upon an _average_ charge of 5d. per 1,000 cubic feet, will vary +from L6 14s. per indicated horse power per annum to L18 13s. 3d., +according to circumstances and mode of application. + +A compressed air motor is an exceedingly simple machine--much simpler +than an ordinary steam engine. But the air may also be used in an +ordinary steam engine; and in this case it can be much simplified in +many details. Very little packing is needed, as there is no nuisance +from gland leakage; the friction is therefore very slight. Pistons and +glands are packed with soapstone, or other self-lubricating packing; and +no oil is required except for bearings, etc. The company will undertake +the periodical inspection and overhauling of engines supplied with their +power, all which is included in the estimates. The total cost to +consumers, with air at an average of 5d. per 1,000 cubic feet, may +therefore be fairly taken as follows: + + Min. Max. + Cost of air used L6 14 01/2 L18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 121/2 per cent. on + L10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + L8 19 01/2 L20 18 3 + +The maximum case would apply only to direct acting engines, such as +Tangye pumps, air power hammers, etc., where the air is full on till the +end of the stroke, and where there is no expansion. The minimum given is +at the average rate of 5d. per 1,000 cubic feet; but as there will be +rates below this, according to a sliding scale, we may fairly take it +that the lowest charge will fall considerably below L6 per indicated +horse power per annum.--_Journal of Gas Lighting_. + + * * * * * + + + + +THE BERTHON COLLAPSIBLE CANOE. + + +An endeavor has often been made to construct a canoe that a person can +easily carry overland and put into the water without aid, and convert +into a sailboat. The system that we now call attention to is very well +contrived, very light, easily taken apart, and for some years past has +met with much favor. + +[Illustration: FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.] + +Mr. Berthon's canoes are made of impervious oil-skin. Form is given them +by two stiff wooden gunwales which are held in position by struts that +can be easily put in and taken out. The model shown in the figure is +covered with oiled canvas, and is provided with a double paddle and a +small sail. Fig. 2 represents it collapsed and being carried overland. + +[Illustration: FIG. 2.--THE SAME BEING CARRIED OVERLAND.] + +Mr. Berthon is manufacturing a still simpler style, which is provided +with two oars, as in an ordinary canoe. This model, which is much used +in England by fishermen and hunters, has for several years past been +employed in the French navy, in connection with movable defenses. At +present, every torpedo boat carries one or two of these canoes, each +composed of two independent halves that may be put into the water +separately or be joined together by an iron rod. + +These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure without +danger.[1]--_La Nature_. + +[Footnote 1: For detailed description see SUPPLEMENT, No. 84.] + + * * * * * + + + + +THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN STEAM +RAILROAD. + + +There was great excitement in Nuernberg on the 7th of December, 1835, on +which day the first German railroad was opened. The great square on +which the buildings of the Nuernberg and Furth "Ludwig's Road" stood, the +neighboring streets, and, in fact, the whole road between the two +cities, was filled with a crowd of people who flocked from far and near +to see the wonderful spectacle. For the first time, a railroad train +filled with passengers was to be drawn from Nuernberg to Furth by the +invisible power of the steam horse. At eight o'clock in the morning, the +civil and military authorities, etc., who took part in the celebration +were assembled on the square, and the gayly decorated train started off +to an accompaniment of music, cannonading, cheering, etc. Everything +passed off without an accident; the work was a success. The engraving in +the lower right-hand corner represents the engine and cars of this road. + +It will be plainly seen that such a revolution could not be accomplished +easily, and that much sacrifice and energy were required of the leaders +in the enterprise, prominent among whom was the merchant Johannes +Scharrer, who is known as the founder of the "Ludwig's Road." + +One would naturally suppose that such an undertaking would have met with +encouragement from the Bavarian Government, but this was not the case. +The starters of the enterprise met with opposition on every side; much +was written against it, and many comic pictures were drawn showing +accidents which would probably occur on the much talked of road. Two of +these pictures are shown in the accompanying large engraving, taken from +the _Illustrirte Zeitung_. As shown in the center picture, right hand, +it was expected by the railway opponents that trains running on tracks +at right angles must necessarily come in collision. If anything happened +to the engine, the passengers would have to get out and push the cars, +as shown at the left. + +[Illustration: JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF THE +OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--AT NURNBERG] + +Much difficulty was experienced in finding an engineer capable of +attending to the construction of the road; and at first it was thought +that it would be best to engage an Englishman, but finally Engineer +Denis, of Munich, was appointed. He had spent much time in England and +America studying the roads there, and carried on this work to the entire +satisfaction of the company. + +All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to be +given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first prize in +the competitive trials at Rainhill in 1829, delivered an engine of ten +horse power, which is still known in Nuernberg as "Der Englander." + +Fifty years have passed, and, as Johannes Scharrer predicted, the +Ludwig's Road has become a permanent institution, though it now forms +only a very small part of the network of railroads which covers every +portion of Germany. What changes have been made in railroads during +these fifty years! Compare the present locomotives with the one made by +Cugnot in 1770, shown in the upper left-hand cut, and with the work of +the pioneer Geo. Stephenson, who in 1825 constructed the first passenger +railroad in England, and who established a locomotive factory in +Newcastle in 1824. Geo. Stephenson was to his time what Mr. Borsig, +whose great works at Moabit now turn out from 200 to 250 locomotives a +year, is to our time. + +Truly, in this time there can be no better occasion for a celebration of +this kind than the fiftieth anniversary of the opening of the first +German railroad, which has lately been celebrated by Nuernberg and Furth. + +The lower left-hand view shows the locomotive De Witt Clinton, the third +one built in the United States for actual service, and the coaches. The +engine was built at the West Point Foundry, and was successfully tested +on the Mohawk and Hudson Railroad between Albany and Schenectady on Aug. +9, 1831. + + * * * * * + + + + +IMPROVED COAL ELEVATOR. + + +An illustration of a new coal elevator is herewith presented, which +presents advantages over any incline yet used, so that a short +description may be deemed interesting to those engaged in the coaling +and unloading of vessels. The pen sketch shows at a glance the +arrangement and space the elevator occupies, taking less ground to do +the same amount of work than any other mode heretofore adopted, and the +first cost of erecting is about the same as any other. + +When the expense of repairing damages caused by the ravages of winter is +taken into consideration, and no floats to pump out or tracks to wash +away, the advantages should be in favor of a substantial structure. + +The capacity of this hoist is to elevate 80,000 bushels in ten hours, at +less than one-half cent per bushel, and put coal in elevator, yard, or +shipping bins. + +[Illustration: IMPROVED COAL ELEVATOR.] + +The endless wire rope takes the cars out and returns them, dispensing +with the use of train riders. + +A floating elevator can distribute coal at any hatch on steam vessels, +as the coal has to be handled but once; the hoist depositing an empty +car where there is a loaded one in boat or barge, requiring no swing of +the vessel. + +Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor and +builder, and has them in use in the U.S. engineering service.--_Coal +Trade Journal_. + + * * * * * + + + + +STEEL-MAKING LADLES. + + +The practice of carrying melted cast iron direct from the blast furnace +to the Siemens hearth or the Bessemer converter saves both money and +time. It has rendered necessary the construction of special plant in the +form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson & +Co., of Preston, make the construction of these ladles a specialty, and +by their courtesy, says _The Engineer_, we are enabled to illustrate +four different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel foundry +work, and one of these for the Siemens-Martin process is illustrated by +Fig. 1. These ladles are made in sizes to take from five to fifteen ton +charges, or larger if required, and are mounted on a very strong +carriage with a backward and forward traversing motion, and tipping gear +for the ladle. The ladles are butt jointed, with internal cover strips, +and have a very strong band shrunk on hot about half way in the depth of +the ladle. This forms an abutment for supporting the ladle in the +gudgeon band, being secured to this last by latch bolts and cotters. The +gearing is made of cast steel, and there is a platform at one end for +the person operating the carriage or tipping the ladle. Stopper gear and +a handle are fitted to the ladles to regulate the flow of the molten +steel from the nozzle at the bottom. + +[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.] + +Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It +requires no description. Fig. 3 shows a tremendous ladle constructed for +the North-Eastern Steel Company, for carrying molten metal from the +blast furnace to the converter. It holds ten tons with ease. It is an +exceptionally strong structure. The carriage frame is constructed +throughout of 1 in. wrought-iron plated, and is made to suit the +ordinary 4 ft. 81/2 in. railway gauge. The axle boxes are cast iron, +fitted with gun-metal steps. The wheels are made of forged iron, with +steel tires and axles. The carriage is provided with strong oak buffers, +planks, and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of 1/2 in. wrought-iron +plates, butt jointed, and double riveted butt straps. The trunnions and +flange couplings are of cast steel. The tipping gear, clearly shown in +the engraving, consists of a worm and wheel, both of steel, which can be +fixed on either side of the ladle as may be desired. From this it will +be seen that Messrs. Stevenson & Co. have made a thoroughly strong +structure in every respect, and one, therefore, that will commend itself +to most steel makers. We understand that these carriages are made in +various designs and sizes to meet special requirements. Thus, Fig. 4 +shows one of different design, made for a steel works in the North. This +is also a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great care +and honesty of purpose is required in making these structures. A +breakdown might any moment pour ten tons of molten metal on the ground, +with the most horrible results. + + * * * * * + + + + +APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE +SURFACE OF CONDUCTORS. + + +Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and +ingenious apparatus which permits of demonstrating that electricity +develops only on the surface of conductors. It consists (see figure) +essentially of a yellow-metal disk, M, fixed to an insulating support, +F, and carrying a concentric disk of ebonite, H. This latter receives a +hollow and closed hemisphere, J, of yellow metal, whose base has a +smaller diameter than that of the disk, H, and is perfectly insulated by +the latter. Another yellow-metal hemisphere, S, open below, is connected +with an insulating handle, G. The basal diameter of this second +hemisphere is such that when the latter is placed over J its edge rests +upon the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a hollow, +closed hemisphere that imprisons the hemisphere, J, which is likewise +hollow and closed, and perfectly insulated from the former. + +[Illustration] + +The shell, S, is provided internally with a curved yellow-metal spring, +whose point of attachment is at B, and whose free extremity is connected +with an ebonite button, K, which projects from the shell, S. By pressing +this button, a contact may be established between the external +hemisphere (formed of the pieces, S and M), and the internal one, J. As +soon as the button is left to itself, the spring again begins to bear +against the interior surface of S, and the two hemispheres are again +insulated. + +The experiment is performed in this wise: The shell, S, is removed. Then +a disk of steatite affixed to an insulating handle is rubbed for a few +instants with a fox's "brush," and held near J until a spark occurs. +Then the apparatus is grasped by the support, F, and an elder-pith ball +suspended by a flaxen thread from a good conducting support is brought +near J. The ball will be quickly repelled, and care must be taken that +it does not come into contact with J. After this the apparatus is placed +upon a table, the shell, S, is taken by its handle, G, and placed in the +position shown in the figure, and a momentary contact is established +between the two hemispheres by pressing the button, K. Then the shell, +S, is lifted, and the disk, M, is touched at the same time with the +other hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, thus +proving that all the electricity passed from J to S at the moment of +contact.--_La Lumiere Electrique_. + + * * * * * + + + + +THE COLSON TELEPHONE. + + +This apparatus has recently been the object of some experiments which +resulted in its being finally adopted in the army. We think that our +readers will read a description of it with interest. Its mode of +construction is based upon a theoretic conception of the lines of force, +which its inventor explains as follows in his Elementary Treatise on +Electricity: + +"To every position of the disk of a magnetic telephone with respect to +the poles of the magnet there corresponds a certain distribution of the +lines of force, which latter shift themselves when the disk is +vibrating. If the bobbin be met by these lines in motion, there will +develop in its wire a difference of potential that, according to +Faraday's law, will be proportional to their number. All things equal, +then, a telephone transmitter will be so much the more potent in +proportion as the lines set in motion by the vibrations of the disk and +meeting the bobbin wire are greater in number. In like manner, a +receiver will be so much the more potent in proportion as the lines of +force, set in motion by variations in the induced currents that are +traversing the bobbin and meeting the disk, are more numerous. It will +consequently be seen that, generally speaking, it is well to send as +large a number of lines of force as possible through the bobbin." + +[Illustration: FIG. 1.--THE COLSON TELEPHONE.] + +In order to obtain such a result, the thin tin-plate disk has to be +placed between the two poles of the magnet. The pole that carries the +fine wire bobbin acts at one side and in the center of the disk, while +the other is expanded at the extremity and acts upon the edge and the +other side. This pole is separated from the disk by a copper washer, and +the disk is thus wholly immersed in the magnetic field, and is traversed +by the lines of force radiatingly. + +This telephone is being constructed by Mr. De Branville, with the +greatest care, in the form of a transmitter (Fig. 2) and receiver (Fig. +3). At A may be seen the magnet with its central pole, P, and its +eccentric one, P'. This latter traverses the vibrating disk, M, through +a rubber-lined aperture and connects with the soft iron ring, F, that +forms the polar expansion. These pieces are inclosed in a nickelized +copper box provided with a screw cap, C. The resistance of both the +receiver and transmitter bobbin is 200 ohms. + +[Illustration: FIG. 2.--TRANSMITTER TAKEN APART.] + +The transmitter is 31/2 in. in diameter, and is provided with a +re-enforcing mouthpiece. It is regulated by means of a screw which is +fixed in the bottom of the box, and which permits of varying the +distance between the disk and the core that forms the central pole of +the magnet. The regulation, when once effected, lasts indefinitely. The +regulation of the receiver, which is but 21/4 in. in diameter, is +performed once for all by the manufacturer. One of the advantages of +this telephone is that its regulation is permanent. Besides this, it +possesses remarkable power and clearness, and is accompanied with no +snuffling sounds, a fact doubtless owing to all the molecules of the +disk being immersed in the magnetic field, and to the actions of the two +poles occurring concentrically with the disk. As we have above said, +this apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used by +the artillery service in the organization of observatories from which to +watch firing, and the receiver is added to the apparatus pertaining to +military telegraphy. The two small receivers are held to the lens of the +operator by the latter's hat strap, while the transmitter is suspended +in a case supported by straps, with the mouthpieces near the face (Fig. +1). + +In the figure, the case is represented as open, so as to show the +transmitter. The empty compartment below is designed for the reception +and carriage of the receivers, straps, and flexible cords. This +arrangement permits of calling without the aid of special apparatus, and +it has also the advantage of giving entire freedom to the man on +observation, this being something that is indispensable in a large +number of cases. + +[Illustration: FIG. 3.--RECEIVER TAKEN APART.] + +In certain applications, of course, the receivers may be combined with a +microphone; yet on an aerial as well as on a subterranean line the +transmitter produces effects which, as regards intensity and clearness, +are comparable with those of a pile transmitter. + +Stations wholly magnetic may be established by adding to the transmitter +and two receivers a Sieur phonic call, which will actuate them +powerfully, and cause them to produce a noise loud enough for a call. It +would be interesting to try this telephone on a city line, and to a +great distance on those telegraph lines that are provided with the Van +Rysselberghe system. Excellent results would certainly be obtained, for, +as we have recently been enabled to ascertain, the voice has a +remarkable intensity in this telephone, while at the same time perfectly +preserving its quality.--_La Nature_. + + * * * * * + +[NATURE.] + + + + +THE MELDOMETER. + + +The apparatus which I propose to call by the above name +([mu][epsilon][lambda][delta][omega], to melt) consists of an adjunct to +the mineralogical microscope, whereby the melting-points of minerals may +be compared or approximately determined and their behavior watched at +high temperatures either alone or in the presence of reagents. + +As I now use it, it consists of a narrow ribbon of platinum (2 mm. wide) +arranged to traverse the field of the microscope. The ribbon, clamped in +two brass clamps so as to be readily renewable, passes bridgewise over a +little scooped-out hollow in a disk of ebony (4 cm. diam.). The clamps +also take wires from a battery (3 Groves cells); and an adjustable +resistance being placed in circuit, the strip can be thus raised in +temperature up to the melting-point of platinum. + +The disk being placed on the stage of the microscope the platinum strip +is brought into the field of a 1" objective, protected by a glass slip +from the radiant heat. The observer is sheltered from the intense light +at high temperatures by a wedge of tinted glass, which further can be +used in photometrically estimating the temperature by using it to obtain +extinction of the field. Once for all approximate estimations of the +temperature of the field might be made in terms of the resistance of the +platinum strip, the variation of such resistance with rise of +temperature being known. Such observations being made on a suitably +protected strip might be compared with the wedge readings, the latter +being then used for ready determinations. Want of time has hindered me +from making such observations up to this. + +The mineral to be experimented on is placed in small fragments near the +center of the platinum ribbon, and closely watched while the current is +increased, till the melting-point of the substance is apparent. Up to +the present I have only used it comparatively, laying fragments of +different fusibilities near the specimen. In this way I have melted +beryl, orthoclase, and quartz. I was much surprised to find the last +mineral melt below the melting-point of platinum. I have, however, by me +as I write, a fragment, formerly clear rock-crystal, so completely fused +that between crossed Nicols it behaves as if an amorphous body, save in +the very center where a speck of flashing color reveals the remains of +molecular symmetry. Bubbles have formed in the surrounding glass. + +Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way. + +Topaz whitens to a milky glass--apparently decomposing, throwing out +filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot platinum, +causes rings of color to appear round the specimen. I have now been +using the apparatus for nearly a month, and in its earliest days it led +me right in the diagnosis of a microscopical mineral, iolite, not before +found in our Irish granite, I think. The unlooked-for characters of the +mineral, coupled with the extreme minuteness of the crystals, led me +previously astray, until my meldometer fixed its fusibility for me as +far above the suspected bodies. + +Carbon slips were at first used, as I was unaware of the capabilities of +platinum. + +A form of the apparatus adapted, at Prof. Fitzgerald's suggestion, to +fit into the lantern for projection on the screen has been made for me +by Yeates. In this form the heated conductor passes both below and above +the specimen, which is regarded from a horizontal direction. + +J. JOLY. + +Physical Laboratory, Trinity College, Dublin. + + * * * * * + +[AMERICAN ANNALS OF THE DEAF AND DUMB.] + + + + +TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF DEAF-MUTES. + + +Progress in electrical science is daily causing the world to open its +eyes in wonder and the scientist to enlarge his hopes for yet greater +achievements. The practical uses to which this subtile fluid, +electricity, is being put are causing changes to be made in time-tested +methods of doing things in domestic, scientific, and business circles, +and the time has passed when startling propositions to accomplish this +or that by the assistance of electricity are dismissed with incredulous +smiles. This being the case, no surprise need follow the announcement of +a device to facilitate the imparting of instruction to deaf children +which calls into requisition some service from electricity. + +The sense of touch is the direct medium contemplated, and it is intended +to convey, with accuracy and rapidity, messages from the operator (the +teacher) to the whole class simultaneously by electrical +transmission.[1] + +[Footnote 1: By the same means two deaf-mutes, miles apart, might +converse with each other, and the greatest difficulty in the way of a +deaf-mute becoming a telegraph operator, that of receiving messages, +would be removed. The latter possibilities are incidentally mentioned +merely as of scientific interest, and not because of their immediate +practical value. The first mentioned use to which the device may be +applied is the one considered by the writer as possibly of practical +value, the consideration of which suggested the appliance to him.] + +An alphabet is formed upon the palm of the left hand and the inner side +of the fingers, as shown by the accompanying cut, which, to those +becoming familiar with it, requires but a touch upon a certain point of +the hand to indicate a certain letter of the alphabet. + +A rapid succession of touches upon various points of the hand is all +that is necessary in spelling a sentence. The left hand is the one upon +which the imaginary alphabet is formed, merely to leave the right hand +free to operate without change of position when two persons only are +conversing face to face. + +The formation of the alphabet here figured is on the same principle as +one invented by George Dalgarno, a Scottish schoolmaster, in the year +1680, a cut of which maybe seen on page 19 of vol. ix. of the _Annals_, +accompanying the reprint of a work entitled "_Didascalocophus_." +Dalgarno's idea could only have been an alphabet to be used in +conversation between two persons _tete a tete_, and--except to a limited +extent in the Horace Mann School and in Professor Bell's teaching--has +not come into service in the instruction of deaf-mutes or as a means of +conversation. There seems to have been no special design or system in +the arrangement of the alphabet into groups of letters oftenest +appearing together, and in several instances the proximity would +seriously interfere with distinct spelling; for instance, the group "u," +"y," "g," is formed upon the extreme joint of the little finger. The +slight discoverable system that seems to attach to his arrangement of +the letters is the placing of the vowels in order upon the points of the +fingers successively, beginning with the thumb, intended, as we suppose, +to be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly as +another. If any arrangement has advantage over another, we consider it +the one which has so grouped the letters as to admit of an increased +rapidity of manipulation. The arrangement of the above alphabet, it is +believed, does admit of this. Yet it is not claimed that it is as +perfect as the test of actual use may yet make it. Improvements in the +arrangement will, doubtless, suggest themselves, when the alterations +can be made with little need of affecting the principle. + +In order to transmit a message by this alphabet, the following described +appliance is suggested: A matrix of cast iron, or made of any suitable +material, into which the person receiving the message (the pupil) places +his left hand, palm down, is fixed to the table or desk. The matrix, +fitting the hand, has twenty-six holes in it, corresponding in position +to the points upon the hand assigned to the different letters of the +alphabet. In these holes are small styles, or sharp points, which are so +placed as but slightly to touch the hand. Connected with each style is a +short line of wire, the other end of which is connected with a principal +wire leading to the desk of the operator (the teacher), and there so +arranged as to admit of opening and closing the circuit of an electric +current at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric impulses, +intended to act mechanically upon all the styles connected with it. By +these impulses, produced by the will of the sender, the styles are +driven upward with a quick motion, but with only sufficient force to be +felt and located upon the hand by the recipient. Twenty-six of these +principal or primary wires are run from the teacher's desk (there +connected with as many buttons) under the floor along the line of +pupils' desks. From each matrix upon the desk run twenty-six secondary +wires down to and severally connecting with the twenty-six primary wires +under the floor. The whole system of wires is incased so as to be out of +sight and possibility of contact with foreign substances. The keys or +buttons upon the desk of the teacher are systematically arranged, +somewhat after the order of those of the type writer, which allows the +use of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," "c," +etc., to "z," and an electric current over the primary wire running from +a certain button (say the one labeled "a") affects only those secondary +wires connected with the styles that, when excited, produce upon the +particular spot of the hands of the receivers the tactile impression to +be interpreted as "a." And so, whenever the sender touches any of the +buttons on his desk, immediately each member of the class feels upon the +palm of his hand the impression meant to be conveyed. The contrivance +will admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric bell. +It was first thought of conveying the impressions directly by slight +electric shocks, without the intervention of further mechanical +apparatus, but owing to a doubt as to the physical effect that might be +produced upon the persons receiving, and as to whether the nerves might +not in time become partly paralyzed or so inured to the effect as to +require a stronger and stronger current, that idea was abandoned, and +the one described adopted. A diagram of the apparatus was submitted to a +skillful electrical engineer and machinist of Hartford, who gave as his +opinion that the scheme was entirely feasible, and that a simple and +comparatively inexpensive mechanism would produce the desired result. + +[Illustration: TOUCH TRANSMISSION BY ELECTRICITY.] + +The matter now to consider, and the one of greater interest to the +teacher of deaf children, is, Of what utility can the device be in the +instruction of deaf-mutes? What advantage is there, not found in the +prevailing methods of communication with the deaf, i.e., by gestures, +dactylology, speech and speech-reading, and writing? + +I. The language of gestures, first systematized and applied to the +conveying of ideas to the deaf by the Abbe de l'Epee during the latter +part of the last century, has been, in America, so developed and +improved upon by Gallaudet, Peet, and their successors, as to leave but +little else to be desired for the purpose for which it was intended. The +rapidity and ease with which ideas can be expressed and understood by +this "language" will never cease to be interesting and wonderful, and +its value to the deaf can never fail of being appreciated by those +familiar with it. But the genius of the language of signs is such as to +be in itself of very little, if any, direct assistance in the +acquisition of syntactical language, owing to the diversity in the order +of construction existing between the English language and the language +of signs. Sundry attempts have been made to enforce upon the +sign-language conformity to the English order, but they have, in all +cases known to the writer, been attended with failure. The sign-language +is as immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given with +great success upon the basis of the sign-language. But in all such +exercises there must be a translation from one language to the other. +The desideratum still exists of an increased percentage of pupils +leaving our schools for the deaf, possessing a facility of expression in +English vernacular. This want has been long felt, and endeavoring to +find a reason for the confessedly low percentage, the sign-language has +been too often unjustly accused. It is only when the sign-language is +abused that its merit as a means of instruction degenerates. The most +ardent admirers of a proper use of signs are free to admit that any +excessive use by the pupils, which takes away all opportunities to +express themselves in English, is detrimental to rapid progress in +English expression. + +II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as one +of the elements of the American or eclectic method. This advantage, +however, is not of so great importance as to outweigh the disadvantages +when, as has honestly been attempted, it asserts its independence of +other methods. Very few persons indeed, even after long practice, become +sufficiently skillful in spelling on the fingers to approximate the +rapidity of speech. But were it possible for all to become rapid +spellers, another very important requisite is necessary before the +system could be a perfect one, that is, the ability to _read_ rapid +spelling. The number of persons capable of reading the fingers beyond a +moderate degree of rapidity is still less than the number able to spell +rapidly. While it is physically possible to follow rapid spelling for +twenty or thirty minutes, it can scarcely be followed longer than that. +So long as this is true, dactylology can hardly claim to be more than +one of the _elements_ of a system of instruction for the deaf. + +III. Articulate speech is another of the elements of the eclectic +method, employed with success inversely commensurate with the degree of +deficiency arising from deafness. Where the English order is already +fixed in his mind, and he has at an early period of life habitually used +it, there is comparatively little difficulty in instructing the deaf +child by speech, especially if he have a quick eye and bright intellect. +But the number so favored is a small percentage of the great body of +deaf-mutes whom we are called upon to educate. When it is used as a +_sole_ means of educating the deaf as a class its inability to stand +alone is as painfully evident as that of any of the other component +parts of the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to what +a word is if spelled slowly enough, and if its meaning has been learned. +This cannot be said of speech. Between many words there is not, when +uttered, the slightest visible distinction. Between a greater number of +others the distinction is so slight as to cause an exceedingly nervous +hesitation before a guess can be given. Too great an imposition is put +upon the eye to expect it to follow unaided the extremely circumscribed +gestures of the organs of speech visible in ordinary speaking. The ear +is perfection as an interpreter of speech to the brain. It cannot +correctly be said that it is _more_ than perfection. It is known that +the ear, in the interpretation of vocal sounds, is capable of +distinguishing as many as thirty-five sounds per second (and oftentimes +more), and to follow a speaker speaking at the rate of more than two +hundred words per minute. If this be perfection, can we expect the _eye_ +of ordinary mortal to reach it? Is there wonder that the task is a +discouraging one for the deaf child? + +But it has been asserted that while a large percentage (practically all) +of the deaf _can_, by a great amount of painstaking and practice, become +speech readers in some small degree, a relative degree of facility in +articulation is not nearly so attainable. As to the accuracy of this +view, the writer cannot venture an opinion. Judging from the average +congenital deaf-mute who has had special instruction in speech, it can +safely be asserted that their speech is laborious, and far, very far, +from being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that as an +unaided means of instruction it cannot be a success, for English neither +understood when spoken, nor spoken by the pupil, cannot but remain a +foreign language, requiring to pass through some other form of +translation before it becomes intelligible. + +There are the same obstacles in the use of the written or printed word +as have been mentioned in connection with dactylology, namely, lack of +rapidity in conveying impressions through the medium of the English +sentence. + +I have thus hastily reviewed the several means which teachers generally +are employing to impart the use of English to deaf pupils, for the +purpose of showing a common difficulty. The many virtues of each have +been left unnoticed, as of no pertinence to this article. + +The device suggested at the beginning of this paper, claiming to be +nothing more than a school room appliance intended to supplement the +existing means for giving a knowledge and practice of English to the +deaf, employs as its interpreter a different sense from the one +universally used. The sense of sight is the sole dependence of the deaf +child. Signs, dactylology, speech reading, and the written and printed +word are all dependent upon the eye for their value as educational +instruments. It is evident that of the two senses, sight and touch, if +but one could be employed, the choice of sight as the one best adapted +for the greatest number of purposes is an intelligent one; but, as the +choice is not limited, the question arises whether, in recognizing the +superior adaptability to our purpose of the one, we do not lose sight of +a possibly important, though secondary, function in the other. If sight +were all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we acquire +our vernacular is of divine, and not of human, origin, and the senses +designed for special purposes are not interchangeable without loss. The +theory that the loss of a certain sense is nearly, if not quite, +compensated for by increased acuteness of the remaining ones has been +exploded. Such a theory accuses, in substance, the Maker of creating +something needless, and is repugnant to the conceptions we have of the +Supreme Being. When one sense is absent, the remaining senses, in order +to equalize the loss, have imposed upon them an unusual amount of +activity, from which arises skill and dexterity, and by which the loss +of the other sense is in some measure alleviated, but not supplied. No +_additional_ power is given to the eye after the loss of the sense of +hearing other than it might have acquired with the same amount of +practice while both faculties were active. The fact, however, that the +senses, in performing their proper functions, are not overtaxed, and are +therefore, in cases of emergency, capable of being extended so as to +perform, in various degrees, additional service, is one of the wise +providences of God, and to this fact is due the possibility of whatever +of success is attained in the work of educating the deaf, as well as the +blind. + +In the case of the blind, the sense of touch is called into increased +activity by the absence of the lost sense; while in the case of the +deaf, sight is asked to do this additional service. A blind person's +education is received principally through the _two_ senses of hearing +and touch. Neither of these faculties is so sensible to fatigue by +excessive use as is the sense of sight, and yet the eye has, in every +system of instruction applied to the deaf, been the sole medium. In no +case known to the writer, excepting in the celebrated case of Laura +Bridgman and a few others laboring under the double affliction of +deafness and blindness, has the sense of touch been employed as a means +of instruction.[1] + +[Footnote 1: This article was written before Professor Bell had made his +interesting experiments with his "parents' class" of a touch alphabet, +to be used upon the pupil's shoulder in connection with the oral +teaching.--E.A.F.] + +Not taking into account the large percentage of myopes among the deaf, +we believe there are other cogent reasons why, if found practicable, the +use of the sense of touch may become an important element in our +eclectic system of teaching. We should reckon it of considerable +importance if it were ascertained that a portion of the same work now +performed by the eye could be accomplished equally as well through +feeling, thereby relieving the eye of some of its onerous duties. + +We see no good reason why such accomplishment may not be wrought. If, +perchance, it were discovered that a certain portion could be performed +in a more efficient manner, its value would thus be further enhanced. + +In theory and practice, the teacher of language to the deaf, by whatever +method, endeavors to present to the eye of the child as many completed +sentences as are nominally addressed to the ear--having them "caught" by +the eye and reproduced with as frequent recurrence as is ordinarily done +by the child of normal faculties. + +In our hasty review of the methods now in use we noted the inability to +approximate this desirable process as a common difficulty. The facility +now ordinarily attained in the manipulation of the type writer, and the +speed said to have been reached by Professor Bell and a private pupil of +his by the Dalgarno touch alphabet, when we consider the possibility of +a less complex mechanism in the one case and a more systematic grouping +of the alphabet in the other, would lead us to expect a more rapid means +of communication than is ordinarily acquired by dactylology, speech (by +the deaf), or writing. Then the ability to receive the communication +rapidly by the sense of feeling will be far greater. No part of the body +except the point of the tongue is as sensible to touch as the tips of +the fingers and the palm of the hand. Tactile discrimination is so acute +as to be able to interpret to the brain significant impressions produced +in very rapid succession. Added to this advantage is the greater one of +the absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the tympanum of +the ear. To sum up, then, the advantages of the device we find-- + +First. A more rapid means of communication with the deaf by syntactic +language, admitting of a greater amount of practice similar to that +received through the ear by normal children. + +Second. Ability to receive this rapid communication for a longer +duration and without ocular strain. + +Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender. + +Fourth. In articulation and speech-reading instruction, the power to +assist a class without distracting the attention of the eye from the +vocal organs of the teacher. + +Fifth. Freedom of the right hand of the pupil to make instantaneous +reproduction in writing of the matter being received through the sense +of feeling, thereby opening the way for a valuable class exercise. + +Sixth. The possible mental stimulus that accompanies the mastery of a +new language, and the consequent ability to receive known ideas through +a new medium. + +Seventh. A fresh variety of class exercises made possible. + +The writer firmly believes in the good that exists in all methods that +are, or are to be; in the interdependence rather than the independence +of all methods; and in all school-room appliances tending to supplement +or expedite the labors of the teacher, whether they are made of +materials delved from the earth or snatched from the clouds. + +S. TEFFT WALKER, + +_Superintendent of the Kansas Institution, Olathe, Kans_. + + * * * * * + + + + +WATER GAS. + +THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON REDUCING AGENTS. + +By B.H. THWAITE. + + +In order to approximately ascertain the relative reducing action of +water gas, carbon monoxide, and superheated steam on iron ore, the +author decided to have carried out the following experiments, which were +conducted by Mr. Carl J. Sandahl, of Stockholm, who also carried out the +analyses. The ore used was from Bilbao, and known as the Ruby Mine, and +was a good average hematite. The carbonaceous material was the Trimsaran +South Wales anthracite, and contained about 90 per cent. of carbon. + +A small experimental furnace was constructed of the form shown by +illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the base, +and gradually swelling to 2 ft. 9 in. at the top, built entirely of +fireclay bricks. Two refractory tubes, 2 in. square internally, and the +height of the furnace, were used for the double purpose of producing the +gas and reducing the ore. + +The end of the lower tube rested on a fireclay ladle nozzle, and was +properly jointed with fireclay; through this nozzle the steam or air was +supplied to the inside of the refractory tubes. In each experiment the +ore and fuel were raised to the temperature "of from 1,800 to 2,200 deg. +Fahr." by means of an external fire of anthracite. Great care was taken +to prevent the contact of the solid carbonaceous fuel with the ore. In +each experiment in which steam was used, the latter was supplied at a +temperature equivalent to 35 lb. to the square inch. + +The air for producing the carbon monoxide (CO) gas was used at the +temperature of the atmosphere. As near as possible, the same conditions +were obtained in each experiment, and the equivalent weight of air was +sent through the carbon to generate the same weight of CO as that +generated when steam was used for the production of water gas. + +[Illustration] + +_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled +with ore broken to the size of nuts. The tube, A, was heated to about +2,000 deg. Fahr., the upper one to about 1,500 deg. + +NOTE.--In this experiment, part of the steam was dissociated in passing +through the turned-up end of the steam supply pipe, which became very +hot, and the steam would form with the iron the magnetic oxide +(Fe_{3}O_{4}). The reduction would doubtless be due to this +dissociation. The pieces of ore found on lowest end of the tube, A, were +dark colored and semi-fused; part of one of these pieces was crushed +fine, and tested; see column I. The remainder of these black pieces was +mixed with the rest of the ore contained in tube, A, and ground and +tested; see column II. The ore in upper tube was all broken up together +and tested; see column III. When finely crushed, the color of No. I. was +bluish black; No. II., a shade darker red; No. III., a little darker +than the natural color of the ore. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- + +_Second Experiment, Water Gas_.--The tube, A, was filled with small +pieces of anthracite, and heated until all the volatile matter had been +expelled. The tube, B, was then placed in tube, A, the joint being made +with fireclay, and to prevent the steam from carrying small particles of +solid carbon into ore in the upper tube, the anthracite was divided from +the ore by means of a piece of fine wire gauze. The steam at a pressure +of about 35 lb. to the square inch was passed through the anthracite. +The tube, A, was heated to white heat, the tube, B, at its lower end to +bright red, the top to cherry red. + +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ + +_Four Samples were Tested_.--I. The bottom layer, 11/4 in. thick; the +color of ore quite black, with small particles of reduced spongy +metallic iron. II. Layer above I., 41/4 in. thick; the color was also +black, but showed a little purple tint. III. Layer above II., 5 in. +thick; purple red color. IV. Layer above III., ore a red color. The +analyses gave: + +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- + +NOTE.--All the carbon dioxide (CO_{2}) occurring in the ore as calcic +carbonate was expelled. + +_Third Experiment, Carbon monoxide_ (CO).--The tube A was filled with +anthracite in the manner described for the second experiment, and heated +to drive off the volatile matter, before the ore was placed in the upper +tube, B, and the anthracite was divided from the ore by means of a piece +of fine wire gauze. The lower tube, A, was heated to the temperature of +white heat, the upper one, B, to a temperature of bright red. I. Layer, +1 in. thick from the bottom; ore dark brownish colored. II. Layer 4 in. +thick above I.; ore reddish brown. III. Layer 11 in. thick above II.; +ore red color. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- + +NOTE.--The carbon monoxide (CO) had failed to remove from the ore the +carbon dioxide existing as calcic carbonate. The summary of experiments +in the following table appears to show that the water gas is a more +powerful reducing agent than CO in proportion to the ratio of as + + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 + +Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just now +constructing large experimental plant in which water gas will be used as +the reducing agent. This plant would have been at work before this but +for some defects in the valvular arrangements, which will be entirely +removed in the new modifications of the plant. + + * * * * * + + + + +ANTISEPTIC MOUTH WASH. + + +Where an antiseptic mouth wash is needed, Mr. Sewill prescribes the use +of perchloride of mercury in the following form: One grain of the +perchloride and 1 grain of chloride of ammonium to be dissolved in 1 oz. +of eau de Cologne or tincture of lemons, and a teaspoonful of the +solution to be mixed with two-thirds of a wineglassful of water, making +a proportion of about 1 of perchloride in 5,000 parts.--_Chemist and +Druggist_. + + * * * * * + + + + +ANNATTO. + +[Footnote: Read at an evening meeting of the North British Branch of the +Pharmaceutical Society, January 21.] + +By WILLIAM LAWSON. + + +The subject which I have the honor to bring shortly before your notice +this evening is one that formed the basis of some instructive remarks by +Dr. Redwood in November, 1855, and also of a paper by Dr. Hassall, read +before the Society in London in January, 1856, which latter gave rise to +an animated discussion. The work detailed below was well in hand when +Mr. MacEwan drew my attention to these and kindly supplied me with the +volume containing reports of them. Unfortunately, they deal principally +with the adulterations, while I was more particularly desirous to learn +the composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. Within +the last few years it was one of the articles in considerable demand in +this part of the country; now it is seldom inquired for. This, +certainly, is not because butter coloring has ceased to be employed, and +hence the reason for regretting that the percentage of resin was not +dealt with in the articles referred to, so that a comparison could have +been made between the commercial annatto of that period and that which +exists now. In case some may not be in possession of literature bearing +on it--which, by the way, is very meager--it may not be out of place to +quote some short details as to its source, the processes for obtaining +it, the composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has more +interest for the country than for the town druggist, still, I trust it +will have points of interest for both. + +Annatto is the coloring matter derived from the seeds of an evergreen +plant, _Bixa Orellana_, which grows in the East and West Indian Islands +and South America, in the latter of which it is principally prepared. +Two kinds are imported, Spanish annatto, made in Brazil, and flag or +French, made mostly in Cayenne. These differ considerably in characters +and properties, the latter having a disagreeable putrescent odor, while +the Spanish is rather agreeable when fresh and good. It is, however, +inferior to the flag as a coloring or dyeing agent. The seeds from which +the substance is obtained are red on the outside, and two methods are +followed in order to obtain it. One is to rub or wash off the coloring +matter with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to bruise +the seeds, mix them with water, and allow fermentation to set in, during +which the coloring matter collects at the bottom, from which it is +subsequently removed and brought to the proper consistence by +spontaneous evaporation. These particulars, culled from Dr. Redwood's +remarks, may suffice to show its source and the methods for obtaining +it. + +Dr. John gives the following as the composition of the pulp surrounding +the seeds: Coloring resinous matter, 28; vegetable gluten, 26.5; +ligneous fiber, 20; coloring, 20; extractive matter, 4; and a trace of +spicy and acid matter. + +It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as well as +to preserve it, differs considerably from this; and though it may not be +true, as some hint, that manufacturing in this industry is simply a term +synonymous with adulterating, yet results will afterward be given +tending to show that there are articles in the market which have little +real claim to the title. I tried, but failed, to procure a sample of raw +material on which to work, with a view to learn something of its +characters and properties in this state, and thus be able to contrast it +with the manufactured or commercial article. The best thing to do in the +circumstances, I thought, was to operate on the highest priced sample at +disposal, and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the usual +way, I believe--was a more troublesome operation than it appeared to be, +as the following experiment will show: One hundred grains of No. 8 were +taken, dried thoroughly, reduced to fine powder, and introduced into a +flask containing 4 ounces of alcohol in the form of methylated spirit, +boiled for an hour--the flask during the operation being attached to an +inverted condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated with +diminishing quantities until in all 14 ounces had been used before the +alcoholic solution ceased to turn blue on the addition to it of strong +sulphuric acid, or failed to give a brownish precipitate with stannous +chloride. As the sample contained a considerable quantity of potassium +carbonate, in which the resin is soluble, it was thought that by +neutralizing this it might render the resin more easy of extraction. +This was found to be so, but it was accompanied by such a mass of +extractive as made it in the long run more troublesome, and hence it was +abandoned. Thinking the spirit employed might be too weak, an experiment +with commercial absolute alcohol was carried out as follows: One hundred +grains of a red sample, No. 4, were thoroughly dried, powdered finely, +and boiled in 2 ounces of the alcohol, filtered, and the residue treated +with half an ounce more. This required to be repeated with fresh half +ounces of the alcohol until in all 71/2 were used; the time occupied from +first to last being almost three hours. This was considered +unsatisfactory, besides being very expensive, and so it, also, was set +aside, and a series of experiments with methylated spirit alone was set +in hand. The results showed that the easiest and most satisfactory way +was to take 100 grains (this amount being preferred, as it reduces error +to the minimum), dry thoroughly, powder finely, and macerate with +frequent agitation for twenty-four hours in a few ounces of spirit, then +to boil in this spirit for a short time, filter, and repeat the boiling +with a fresh ounce or so; this, as a rule, sufficing to completely +exhaust it of its resin. Wynter Blyth says that the red resin, or bixin, +is soluble in 25 parts of hot alcohol. It appears from these experiments +that much more is required to dissolve it out of commercial annatto. + +The full process followed consisted in determining the moisture by +drying 100 grains at 212 deg. F. till constant, and taking this dried +portion for estimation of the resin in the way just stated. The +alcoholic extract was evaporated to dryness over a water-bath, the +residue dissolved in solution of sodium carbonate, and the resin +precipitated by dilute sulphuric acid (these reagents being chosen as +the best after numerous trials with others), added in the slightest +possible excess. The resin was collected on a tared double filter paper, +washed with distilled water until the washings were entirely colorless, +dried and weighed. + +The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of them. + +The results are as follows: + + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 + +The first six are the ordinary red rolls, with the exception of No. 4, +which is a red mass, the only one of this class direct from the +manufacturers. The remainder are brown cakes, all except No. 7 being +from the manufacturers direct. The ash of the first two was largely +common salt; that of No. 3 contained, besides this, iron in some +quantity. No. 4 is unique in many respects. It was of a bright red +color, and possessed a not disagreeable odor. It contained the largest +percentage of moisture and the lowest of ash; had, comparatively, a +large amount of coloring matter; was one of the cheapest, and in the +course of some dairy trials, carried out by an intelligent farmer, was +pronounced to be the best suited for coloring butter. So far as my +experience goes, it was a sample of the best commercial excellence, +though I fear the mass of water present and the absence of preserving +substances will assist in its speedy decay. Were such an article easily +procured in the usual way of business, there would not be much to +complain of, but it must not be forgotten that it was got direct from +the manufacturers--a somewhat suggestive fact when the composition of +some other samples is taken into account. No. 5 emitted a disagreeable +odor during ignition. The soluble portion of the ash was mostly common +salt, and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter gave +rise to disagreeable reflections. It was wrapped in a paper saturated +with a strongly smelling linseed oil. When it was boiled in water and +broken up, hairs, among other things, were observed floating about. It +contained some iron. The first cake, No. 7, gave off during ignition an +agreeable odor resembling some of the finer tobaccos, and this is +characteristic more or less of all the cakes. The ash weighed 52 per +cent., the soluble part of which, 18.5, was mostly potassium carbonate, +with some chlorides and sulphates; the insoluble, mostly chalk with iron +and alumina. No. 8--highest priced of all--had in the mass an odor which +I can compare to nothing else than a well rotted farmyard manure. Twenty +parts of the ash were soluble and largely potassium carbonate, the +insoluble being iron for the most part. The mineral portions of Nos. 9 +and 10 closely resemble No. 7. + +On looking over the results, it is found that the red rolls contained +starchy matters in abundance (in No. 4 the starch was to a large extent +replaced by water), and an ash, mostly sodium chloride, introduced no +doubt to assist in its preservation as well as to increase the color of +the resin--a well known action of salt on vegetable reds. The cakes, +which are mostly used for cheese coloring, I believe, all appeared to +contain turmeric, for they gave a more or less distinct reaction with +the boric acid test, and all except No. 8 contained large quantities of +chalk. These results in reference to extractive, etc., reveal nothing +that has not been known before. Wynter Blyth, who gives the only +analyses of annatto I have been able to find, states that the +composition of a fair commercial sample (which I take to mean the raw +article) examined by him was as follows: water, 24.2; resin, 28.8; ash, +22.5; and extractive, 24.5; and that of an adulterated (which I take to +mean a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. 27.3. If +this be correct, it appears that the articles at present in the market, +or at least those which have come in my way, have been wretched +imitations of the genuine thing, and should, instead of being called +adulterated annatto, be called something else adulterated, but not +seriously, with annatto. I have it on the authority of the farmer +previously referred to, that 1/4 of an ounce of No. 4 is amply sufficient +to impart the desired cowslip tint to no less than 60 lb. of butter. +When so little is actually required, it does not seem of very serious +importance whether the adulterant or preservative be flour, chalk, or +water, but it is exasperating in a very high degree to have such +compounds as Nos. 3 and 6 palmed off as decent things when even Nos. 1, +2, and 5 have been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may be +induced to examine the annatto taken into stock more closely than I was +taught to do, and had been in the habit of doing, namely, to see if it +had a good consistence and an odor resembling black sugar, for if so, +the quality was above suspicion. + + * * * * * + + + + +JAPANESE RICE WINE AND SOJA SAUCE. + + +Professor P. Cohn has recently described the mode in which he has +manufactured the Japanese sake or rice wine in the laboratory. The +material used was "Tane Kosi," i.e., grains of rice coated with the +mycelium, conidiophores, and greenish yellow chains of conidia of +_Aspergillus Oryzoe_. The fermentation is caused by the mycelium of this +fungus before the development of the fructification. The rice is first +exposed to moist air so as to change the starch into paste, and then +mixed with grains of the "Tane Kosi." The whole mass of rice becomes in +a short time permeated by the soft white shining mycelium, which imparts +to it the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two or +three days, and then subjected to alcoholic fermentation from the +_Saccharomyces_, which is always present in the rice, but which has +nothing to do with the _Aspergillus_. The fermentation is completed in +two or three weeks, and the golden yellow, sherry-like sake is poured +off. The sample manufactured contained 13.9 per cent. of alcohol. +Chemical investigation showed that the _Aspergillus_ mycelium transforms +the starch into glucose, and thus plays the part of a diastase. + +Another substance produced from the _Aspergillus_ rice is the soja +sauce. The soja leaves, which contain little starch, but a great deal of +oil and casein, are boiled, mixed with roasted barley, and then with the +greenish yellow conidia powder of the _Aspergillus_. After the mycelium +has fructified, the mass is treated with a solution of sodium chloride, +which kills the _Aspergillus_, another fungus, of the nature of a +_Chalaza_, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce then +separates. + + * * * * * + + + + +ALUMINUM. + +[Footnote: Annual address delivered by President J.A. Price before the +meeting of the Scranton Board of Trade, Monday, January 18, 1886.] + +By J.A. PRICE. + + +Iron is the basis of our civilization. Its supremacy and power it is +impossible to overestimate; it enters every avenue of development, and +it may be set down as the prime factor in the world's progress. Its +utility and its universality are hand in hand, whether in the +magnificent iron steamship of the ocean, the network of iron rail upon +land, the electric gossamer of the air, or in the most insignificant +articles of building, of clothing, and of convenience. Without it, we +should have miserably failed to reach our present exalted station, and +the earth would scarcely maintain its present population; it is indeed +the substance of substances. It is the Archimedean lever by which the +great human world has been raised. Should it for a moment forget its +cunning and lose its power, earthquake shocks or the wreck of matter +could not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that it +must give way to a metal that has still greater proportions and vaster +possibilities. Strange and startling as may seem the assertion, yet I +believe it nevertheless to be true that we are approaching the period, +if not already standing upon the threshold of the day, when this magical +element will be radically supplanted, and when this valuable mineral +will be as completely superseded as the stone of the aborigines. With +all its apparent potency, it has its evident weaknesses; moisture is +everywhere at war with it, gases and temperature destroy its fiber and +its life, continued blows or motion crystallize and rob it of its +strength, and acids will devour it in a night. If it be possible to +eliminate all, or even one or more, of these qualities of weakness in +any metal, still preserving both quantity and quality, that metal will +be the metal of the future. + +The coming metal, then, to which our reference is made is aluminum, the +most abundant metal in the earth's crust. Of all substances, oxygen is +the most abundant, constituting about one-half; after oxygen comes +silicon, constituting about one-fourth, with aluminum third in all the +list of substances of the composition. Leaving out of consideration the +constituents of the earth's center, whether they be molten or gaseous, +more or less dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we find +that aluminum is beyond question the most abundant and the most useful +of all metallic substances. + +It is the metallic base of mica, feldspar, slate, and clay. Professor +Dana says: "Nearly all the rocks except limestones and many sandstones +are literally ore-beds of the metal aluminum." It appears in the gem, +assuming a blue in the sapphire, green in the emerald, yellow in the +topaz, red in the ruby, brown in the emery, and so on to the white, +gray, blue, and black of the slates and clays. It has been dubbed "clay +metal" and "silver made from clay;" also when mixed with any +considerable quantity of carbon becoming a grayish or bluish black "alum +slate." + +This metal in color is white and next in luster to silver. It has never +been found in a pure state, but is known to exist in combination with +nearly two hundred different minerals. Corundum and pure emery are ores +that are very rich in aluminum, containing about fifty-four per cent. +The specific gravity is but two and one-half times that of water; it is +lighter than glass or as light as chalk, being only one-third the weight +of iron and one-fourth the weight of silver; it is as malleable as gold, +tenacious as iron, and harder than steel, being next the diamond. Thus +it is capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. Its +variety of transformations is something wonderful. Meeting iron, or even +iron at its best in the form of steel, in the same field, it easily +vanquishes it at every point. It melts at 1,300 degrees F., or at least +600 degrees below the melting point of iron, and it neither oxidizes in +the atmosphere nor tarnishes in contact with gases. The enumeration of +the properties of aluminum is as enchanting as the scenes of a fairy +tale. + +Before proceeding further with this new wonder of science, which is +already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French chemist +Lavoisier, a very magician in the science, groping in the dark of the +last century, evolved the chemical theory of combustion--the existence +of a "highly respirable gas," oxygen, and the presence of metallic bases +in earths and alkalies. With the latter subject we have only to do at +the present moment. The metallic base was predicted, yet not identified. +The French Revolution swept this genius from the earth in 1794, and +darkness closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon the +metallic base of certain earths, but the reflection was so feeble that +the great secret was never revealed. Then a little later the Swedish +Berzelius and the Danish Oersted, confident in the prediction of +Lavoisier and of Davy, went in search of the mysterious stranger with +the aggressive electric current, but as yet to no purpose. It was +reserved to the distinguished German Wohler, in 1827, to complete the +work of the past fifty years of struggle and finally produce the minute +white globule of the pure metal from a mixture of the chloride of +aluminum and sodium, and at last the secret is revealed--the first step +was taken. It took twenty years of labor to revolve the mere discovery +into the production of the aluminum bead in 1846, and yet with this +first step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come. + +Returning again to France some time during the years between 1854 and +1858, and under the patronage of the Emperor Napoleon III., we behold +Deville at last forcing Nature to yield and give up this precious +quality as a manufactured product. Rose, of Berlin, and Gerhard, in +England, pressing hard upon the heels of the Frenchman, make permanent +the new product in the market at thirty-two dollars per pound. The +despair of three-quarters of a century of toilsome pursuit has been +broken, and the future of the metal has been established. + +The art of obtaining the metal since the period under consideration has +progressed steadily by one process after another, constantly increasing +in powers of productivity and reducing the cost. These arts are +intensely interesting to the student, but must be denied more than a +reference at this time. The price of the metal may be said to have come +within the reach of the manufacturing arts already. + +A present glance at the uses and possibilities of this wonderful metal, +its application and its varying quality, may not be out of place. Its +alloys are very numerous and always satisfactory; with iron, producing a +comparative rust proof; with copper, the beautiful golden bronze, and so +on, embracing the entire list of articles of usefulness as well as works +of art, jewelry, and scientific instruments. + +Its capacity to resist oxidation or rust fits it most eminently for all +household and cooking utensils, while its color transforms the dark +visaged, disagreeable array of pots, pans, and kitchen implements into +things of comparative beauty. As a metal it surpasses copper, brass, and +tin in being tasteless and odorless, besides being stronger than either. + +It has, as we have seen, bulk without weight, and consequently may be +available in construction of furniture and house fittings, as well in +the multitudinous requirements of architecture. The building art will +experience a rapid and radical change when this material enters as a +component material, for there will be possibilities such as are now +undreamed of in the erection of homes, public buildings, memorial +structures, etc. etc., for in this metal we have the strength, +durability, and the color to give all the variety that genius may +dictate. + +And when we take a still further survey of the vast field that is +opening before us, we find in the strength without size a most desirable +assistant in all the avenues of locomotion. It is the ideal metal for +railway traffic, for carriages and wagons. The steamships of the ocean +of equal size will double their cargo and increase the speed of the +present greyhounds of the sea, making six days from shore to shore seem +indeed an old time calculation and accomplishment. A thinner as well as +a lighter plate; a smaller as well as a stronger engine; a larger as +well as a less hazardous propeller; and a natural condition of +resistance to the action of the elements; will make travel by water a +forcible rival to the speed attained upon land, and bring all the +distant countries in contact with our civilization, to the profit of +all. This metal is destined to annihilate space even beyond the dream of +philosopher or poet. + +The tensile strength of this material is something equally wonderful, +when wire drawn reaches as high as 128,000 pounds, and under other +conditions reaches nearly if not quite 100,000 pounds to the square +inch. The requirements of the British and German governments in the best +wrought steel guns reach only a standard of 70,000 pounds to the square +inch. Bridges may be constructed that shall be lighter than wooden ones +and of greater strength than wrought steel and entirely free from +corrosion. The time is not distant when the modern wonder of the +Brooklyn span will seem a toy. + +It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube. + +The resistance to corrosion evidently fits this metal for railway +sleepers to take the place of the decaying wooden ties. In this metal +the sleeper may be made as soft and yielding as lead, while the rail may +be harder and tougher than steel, thus at once forming the necessary +cushion and the avoidance of jar and noise, at the same time +contributing to additional security in virtue of a stronger rail. + +In conductivity this metal is only exceeded by copper, having many times +that of iron. Thus in telegraphy there are renewed prospects in the +supplanting of the galvanized iron wire--lightness, strength, and +durability. When applied to the generation of steam, this material will +enable us to carry higher pressure at a reduced cost and increased +safety, as this will be accomplished by the thinner plate, the greater +conductivity of heat, and the better fiber. + +It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in the +mechanic art lies dormant--the size of the machine may be reduced, the +speed and the power increased, realizing the conception of two things +better done than one before. It is one of man's creative acts. + +From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, Paris, +asserts that 120,000 blows will exhaust the usefulness of the cushion of +the stamp machine, and this number of blows is given in a day; and that +when a cushion of aluminum bronze was substituted, it was unaffected +after months of use. + +If we have found a metal that possesses both tensile strength and +resistance to compression; malleability and ductility--the quality of +hardening, softening, and toughening by tempering; adaptability to +casting, rolling, or forging; susceptibility to luster and finish; of +complete homogeneous character and unusually resistant to destructive +agents--mankind will certainly leave the present accomplishments as +belonging to an effete past, and, as it were, start anew in a career of +greater prospects. + +This important material is to be found largely in nearly all the rocks, +or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal." +It is in every clay bank. It is particularly abundant in the coal +measures and is incidental to the shales or slates and clays that +underlie the coal. This under clay of the coal stratum was in all +probability the soil out of which grew the vegetation of the coal +deposits. It is a compound of aluminum and other matter, and, when mixed +with carbon and transformed by the processes of geologic action, it +becomes the shale rock which we know and which we discard as worthless +slate. And it is barely possible that we have been and are still carting +to the refuse pile an article more valuable than the so greatly lauded +coal waste or the merchantable coal itself. We have seen that the best +alumina ore contains only fifty-four per cent. of metal. + +The following prepared table has been furnished by the courtesy and +kindness of Mr. Alex. H. Sherred, of Scranton. + + ALUMINA. + +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 + +It will be seen that the black clay, shale, or slate, has a constituent +of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the +highest. Under every stratum of coal, and frequently mixed with it, are +these under deposits that are rich in the metal. When exposed to the +atmosphere, these shales yield a small deposit of alum. In the +manufacture of alum near Glasgow the shale and slate clay from the old +coal pits constitute the material used, and in France alum is +manufactured directly from the clay. + +Sufficient has been advanced to warrant the additional assertion that we +are here everywhere surrounded by this incomparable mineral, that it is +brought to the surface from its deposits deep in the earth by the +natural process in mining, and is only exceeded in quantity by the coal +itself. Taking a columnar section of our coal field, and computing the +thickness of each shale stratum, we have from twenty-five to sixty feet +in thickness of this metal-bearing substance, which averages over +twenty-five per cent. of the whole in quantity in metal. + +It is readily apparent that the only task now before us is the reduction +of the ore and the extraction of the metal. Can this be done? We answer, +it has been done. The egg has stood on end--the new world has been +sighted. All that now remains is to repeat the operation and extend the +process. Cheap aluminum will revolutionize industry, travel, comfort, +and indulgence, transforming the present into an even greater +civilization. Let us see. + +We have seen the discovery of the mere chemical existence of the metal, +we have stood by the birth of the first white globule or bead by Wohler, +in 1846, and witnesssed its introduction as a manufactured product in +1855, since which time, by the alteration and cheapening of one process +after another, it has fallen in price from thirty-two dollars per pound +in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent +labor at smelting have increased the quantity over a thousandfold and +reduced the cost upward of fifty per cent. + +All these processes involve the application of heat--a mere question of +the appliances. The electric currents of Berzelius and Oersted, the +crucible of Wohler, the closed furnaces and the hydrogen gas of the +French manufacturers and the Bessemer converter apparatus of Thompson, +all indicate one direction. This metal can be made to abandon its bed in +the earth and the rock at the will of man. During the past year, the +Messrs. Cowles, of Cleveland, by their electric smelting process, claim +to have made it possible to reduce the price of the metal to below four +dollars per pound; and there is now erecting at Lockport, New York, a +plant involving one million of capital for the purpose. + +Turning from the employment of the expensive reducing agents to the +simple and sole application of heat, we are unwilling to believe that we +do not here possess in eminence both the mineral and the medium of its +reduction. Whether the electric or the reverberatory or the converter +furnace system be employed, it is surely possible to produce the result. + +To enter into consideration of the details of these constructions would +involve more time than is permitted us on this occasion. They are very +interesting. We come again naturally to the limitless consideration of +powdered fuel, concerning which certain conclusions have been reached. +In the dissociation of water into its hydrogen and oxygen, with the +mingled carbon in a powdered state, we undoubtedly possess the elements +of combustion that are unexcelled on earth, a heat-producing combination +that in both activity and power leaves little to be desired this side of +the production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and furnaces. + +In the hope of stimulating thought to this infinite question of proper +fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope this +Board will not grudgingly devote to the subject, but which is impossible +at present. Do not forget that there is no single spot on the face of +the globe where nature has lavished more freely her choicest gifts. Let +us be active in the pursuit of the treasure and grateful for the +distinguished consideration. + + * * * * * + + + + +THE ORIGIN OF METEORITES. + + +On January 9, Professor Dewar delivered the sixth and last of his series +of lectures at the Royal Institution on "The Story of a Meteorite." [For +the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that +cosmic dust is found on Arctic snows and upon the bottom of the ocean; +all over the world, in fact, at some time or other, there has been a +large deposit of this meteoric dust, containing little round nodules +found also in meteorites. In Greenland some time ago numbers of what +were supposed to be meteoric stones were found; they contained iron, and +this iron, on being analyzed at Copenhagen, was found to be rich in +nickel. The Esquimaux once made knives from iron containing nickel; and +as any such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited the +basaltic coast in Greenland from which some of the supposed meteoric +stones had been brought, and in the middle of the rock large nodules +were found composed of iron and nickel; it, therefore, became evident +that the earth might produce masses not unlike such as come to us as +meteorites. The lecturer here exhibited a section of the Greenland rock +containing the iron, and nickel alloy, mixed with stony crystals, and +its resemblance to a section of a meteorite was obvious. It was 21/2 times +denser than water, yet the whole earth is 51/2 times denser than water, so +that if we could go deep enough, it is not improbable that our own globe +might be found to contain something like meteoric iron. He then called +attention to the following tables: + + _Elementary Substances found in Meteorites_. + + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. + +_Density of Meteorites_. + + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 + +_Interior of the Earth_ + + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 + +[Illustration] + +Twice a year, said Professor Dewar, what are called "falling stars" +maybe plentifully seen; the times of their appearance are in August and +November. Although thousands upon thousands of such small meteors have +passed through our atmosphere, there is no distinct record of one having +ever fallen to the earth during these annual displays. One was said to +have fallen recently at Naples, but on investigation it turned out to be +a myth. These annual meteors in the upper air are supposed to be only +small ones, and to be dissipated into dust and vapor at the time of +their sudden heating; so numerous are they that 40,000 have been counted +in one evening, and an exceptionally great display comes about once in +331/4 years. The inference from their periodicity is, that they are small +bodies moving round the sun in orbits of their own, and that whenever +the earth crosses their orbits, thereby getting into their path, a +splendid display of meteors results. A second display, a year later, +usually follows the exceptionally great display just mentioned, +consequently the train of meteors is of great length. Some of these +meteors just enter the atmosphere of the earth, then pass out again +forever, with their direction of motion altered by the influence of the +attraction of the earth. He here called attention to the accompanying +diagram of the orbits of meteors. + +The lecturer next invited attention to a hollow globe of linen or some +light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and +contained hidden within it the great electro-magnet, weighing 2 cwt., so +often used by Faraday in his experiments. He also exhibited a ball made +partly of thin iron; the globe represented the earth, for the purposes +of the experiment, and the ball a meteorite of somewhat large relative +size. The ball was then discharged at the globe from a little catapult; +sometimes the globe attracted the ball to its surface, and held it +there, sometimes it missed it, but altered its curve of motion through +the air. So was it, said the lecturer, with meteorites when they neared +the earth. Photographs from drawings, by Professor A. Herschel, of the +paths of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, is a +proof that their motions are parallel to each other; the parallel lines +seem to draw to a point at the greatest distance, for the same reason +that the rails of a straight line of railway seem to come from a distant +central point. The most interesting thing about the path of a company of +meteors is, that a comet is known to move in the same orbit; the comet +heads the procession, the meteors follow, and they are therefore, in all +probability, parts of comets, although everything about these difficult +matters cannot as yet be entirely explained; enough, however, is known +to give foundation for the assumption that meteorites and comets are not +very dissimilar. + +The light of a meteorite is not seen until it enters the atmosphere of +the earth, but falling meteorites can be vaporized by electricity, and +the light emitted by their constituents be then examined with the +spectroscope. The light of comets can be directly examined, and it +reveals the presence in those bodies of sodium, carbon, and a few other +well-known substances. He would put a piece of meteorite in the electric +arc to see what light it would give; he had never tried the experiment +before. The lights of the theater were then turned down, and the +discourse was continued in darkness; among the most prominent lines +visible in the spectrum of the meteorite, Professor Dewar specified +magnesium, sodium, and lithium. "Where do meteorites come from?" said +the lecturer. It might be, he continued, that they were portions of +exploded planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular hypothesis +that at some long past time our sun and all his planets existed but as a +volume of gas, which in contracting and cooling formed a hot volume of +rotating liquid, and that as this further contracted and cooled, the +planets, and moons, and planetary rings fell off from it and gradually +solidified, the sun being left as the solitary comparatively uncooled +portion of the original nebula. In partial illustration of this, he +caused a little globe of oil, suspended in an aqueous liquid of nearly +its own specific gravity, to rotate, and as it rotated it was seen, by +means of its magnified image upon the screen, to throw off from its +outer circumference rings and little globes. + + * * * * * + + + + +CANDELABRA CACTUS AND CALIFORNIA WOODPECKER. + +By C.F. HOLDER. + + +One of the most picturesque objects that meet the eye of the traveler +over the great plains of the southern portion of California and New +Mexico is the candelabra cactus. Systematically it belongs to the Cereus +family, in which the notable Night-blooming Cereus also is naturally +included. In tropical or semi-tropical countries these plants thrive, +and grow to enormous size. For example, the Cereus that bears those +great flowers, and blooms at night, exhaling powerful perfume, as we see +them in hothouses in our cold climate, are even in the semi-tropical +region of Key West, on the Florida Reef, seen to grow enormously in +length. + +[Illustration: THE CANDELABRA CACTUS--CEREUS GIGANTEUS.] + +We cultivated several species of the more interesting forms during a +residence on the reef. Our brick house, two stories in height, was +entirely covered on a broad gable end, the branches more than gaining +the top. There is a regular monthly growth, and this is indicated by a +joint between each two lengths. Should the stalk be allowed to grow +without support, it will continue growing without division, and exhibit +stalks five or six feet in length, when they droop, and fall upon the +ground. + +Where there is a convenient resting place on which it can spread out and +attach itself, the stalk throws out feelers and rootlets, which fasten +securely to the wall or brickwork; then, this being a normal growth, +there is a separation at intervals of about a foot. That is, the stalk +grows in one month about twelve inches, and if it has support, the +middle woody stalk continues to grow about an inch further, but has no +green, succulent portion, in fact, looks like a stem; then the other +monthly growth takes place, and ends with a stem, and so on +indefinitely. Our house was entirely covered by the stems of such a +plant, and the flowers were gorgeous in the extreme. The perfume, +however, was so potent that it became a nuisance. Such is the +Night-blooming Cereus in the warm climates, and similarly the Candelabra +Cereus grows in stalks, but architecturally erect, fluted like columns. +The flowers are large, and resemble those of the night-blooming variety. +Some columns remain single, and are amazingly artificial appearing; +others throw off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being clusters +of side shoots, the latter putting out from the trunk regularly, and +standing up parallel to each other. The enormous size these attain is +well shown in the picture. + +Whenever the great stalks of these cacti die, the succulent portion is +dried, and nothing is left but the woody fiber. They are hollow in +places, and easily penetrated. A species of woodpecker, _Melanerpes +formicivorus_, is found to have adopted the use of these dry stalks for +storing the winter's stock of provisions. There are several round +apertures seen on the stems in the pictures, which were pecked by this +bird. This species of woodpecker is about the size of our common robin +or migratory thrush, and has a bill stout and sharp. The holes are +pecked for the purpose of storing away acorns or other nuts; they are +just large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts are +so numerous, the stalk has the appearance of being studded with bullets. +This appearance is more pronounced in cases where the dead trunk of an +oak is used. There are some specimens of the latter now owned by the +American Museum of Natural History, which were originally sent to the +Centennial Exhibition at Philadelphia. They were placed in the +department contributed by the Pacific Railroad Company, and at that time +were regarded as some of the wonders of that newly explored region +through which the railroad was then penetrating. Some portions of the +surface of these logs are nearly entirely occupied by the holes with +acorns in them. The acorns are driven in very tightly in these examples; +much more so than in the cactus plants, as the oak is nearly round, and +the holes were pecked in solid though dead wood. One of the most +remarkable circumstances connected with this habit of the woodpecker is +the length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to make a +journey of sixty miles to accomplish the storing of one acorn. At first +it seemed strange that a bird should spend so much labor to place those +bits of food, and so far away. De Saussure, a Swiss naturalist, +published in the _Bibliotheque Universelle_, of Geneva, entertaining +accounts of the Mexican Colaptes, a variety of the familiar "high hold," +or golden winged woodpecker. They were seen to store acorns in the dead +stalks of the maguey (_Agave Americana_). Sumichrast, who accompanied +him to Central America, records the same facts. These travelers saw +great numbers of the woodpeckers in a region on the slope of a range of +volcanic mountains. There was little else of vegetation than the +_Agave_, whose barren, dead stems were studded with acorns placed there +by the woodpeckers. + +The maguey throws up a stalk about fifteen feet in height yearly, which, +after flowering, grows stalky and brittle, and remains an unsightly +thing. The interior is pithy, but after the death of the stalk the pith +contracts, and leaves the greater portion of the interior hollow, as we +have seen in the case of the cactus branches. How the birds found that +these stalks were hollow is a problem not yet solved, but, nevertheless, +they take the trouble to peck away at the hard bark, and once +penetrated, they commence to fill the interior; when one space is full, +the bird pecks a little higher up, and so continues. + +Dr. Heerman, of California, describes the California _Melanerpes_ as one +of the most abundant of the woodpeckers; and remarks that it catches +insects on the wing like a flycatcher. It is well determined that it +also eats the acorns that it takes so much pains to transport. + +[Illustration: FLOWER OF CEREUS GIGANTEUS.] + +It seems that these birds also store the pine trees, as well as the +oaks. It is not quite apparent why these birds exhibit such variation in +habits; they at times select the more solid trees, where the storing +cannot go on without each nut is separately set in a hole of its own. +There seems an instinct prompting them to do this work, though there may +not be any of the nuts touched again by the birds. Curiously enough, +there are many instances of the birds placing pebbles instead of nuts in +holes they have purposely pecked for them. Serious trouble has been +experienced by these pebbles suddenly coming in contact with the saw of +the mill through which the tree is running. The stone having been placed +in a living tree, as is often the case, its exterior had been lost to +sight during growth. + +Some doubt has been entertained about the purpose of the bird in storing +the nuts in this manner. De Saussure tells us he has witnessed the birds +eating the acorns after they had been placed in holes in trees, and +expresses his conviction that the insignificant grub which is only seen +in a small proportion of nuts is not the food they are in search of. + +C.W. Plass, Esq., of Napa City, California, had an interesting example +of the habits of the California _Melanerpes_ displayed in his own house. +The birds had deposited numbers of acorns in the gable end. A +considerable number of shells were found dropped underneath the eaves, +while some were found in place under the gable, and these were perfect, +having no grubs in them. + +The picture shows a very common scene in New Mexico. The columns, +straight and angular, are often sixty feet in height. It is called torch +cactus in some places. There are many varieties, and as many different +shapes. Some lie on the ground; others, attached to trunks of trees as +parasites, hang from branches like great serpents; but none is so +majestic as the species called systematically _Cereus giganteus_, most +appropriately. The species growing pretty abundantly on the island of +Key West is called candle cactus. It reaches some ten or twelve feet, +and is about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a pretty, +rather picturesque feature in the otherwise barren undergrowth of +shrubbery and small trees. Accompanied by a few flowering cocoa palms, +the view is not unpleasing. The fiber of these plants is utilized in +some coarse manufactures. The maguey, or Agave, is used in the +manufacture of fine roping. Manila hemp is made from a species. The +species whose dried stalks are used by the woodpeckers for their winter +storage was cultivated at Key West, Florida, during several years before +1858. Extensive fields of the Agave stood unappropriated at that period. +Considerable funds were dissipated on this venture. Extensive works were +established, and much confidence was entertained that the scheme would +prove a paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their long +stalks, stand now, increasing every year, until a portion of the island +is overrun with them. + + +CEREUS GIGANTEUS. + +This wonderful cactus, its colossal proportions, and weird, yet grand, +appearance in the rocky regions of Mexico and California, where it is +found in abundance, have been made known to us only through books of +travel, no large plants of it having as yet appeared in cultivation in +this country. It is questionable if ever the natural desire to see such +a vegetable curiosity represented by a large specimen in gardens like +Kew can be realized, owing to the difficulty of importing large stems in +a living condition; and even if successfully brought here, they survive +only a very short time. To grow young plants to a large size seems +equally beyond our power, as plants 6 inches high and carefully managed +are quite ten years old. When young, the stem is globose, afterward +becoming club-shaped or cylindrical. It flowers at the height of 12 +feet, but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of an +immense candelabrum, the base of the stem being as thick as a man's +body. The flower, of which a figure is given here, is about 5 inches +long and wide, the petals cream colored, the sepals greenish white. +Large clusters of flowers are developed together near the top of the +stem. A richly colored edible fruit like a large fig succeeds each +flower, and this is gathered by the natives and used as food under the +name of saguarro. A specimen of this cactus 3 feet high may be seen in +the succulent house at Kew.--_B., The Garden_. + + * * * * * + + + + +HOW PLANTS ARE REPRODUCED. + +[Footnote: Read at a meeting of the Chemists' Assistants' Association. +December 16, 1885.] + +By C.E. STUART, B.Sc. + + +In two previous papers read before this Association I have tried to +condense into as small a space as I could the processes of the nutrition +and of the growth of plants; in the present paper I want to set before +you the broad lines of the methods by which plants are reproduced. + +Although in the great trees of the conifers and the dicotyledons we have +apparently provision for growth for any number of years, or even +centuries, yet accident or decay, or one of the many ills that plants +are heirs to, will sooner or later put an end to the life of every +individual plant. + +Hence the most important act of a plant--not for itself perhaps, but for +its race--is the act by which it, as we say, "reproduces itself," that +is, the act which results in the giving of life to a second individual +of the same form, structure, and nature as the original plant. + +The methods by which it is secured that the second generation of the +plant shall be as well or even better fitted for the struggle of life +than the parent generation are so numerous and complicated that I cannot +in this paper do more than allude to them; they are most completely seen +in cross fertilization, and the adaptation of plant structures to that +end. + +What I want to point out at present are the principles and not so much +the details of reproduction, and I wish you to notice, as I proceed, +what is true not only of reproduction in plants but also of all +processes in nature, namely, the paucity of typical methods of attaining +the given end, and the multiplicity of special variation from those +typical methods. When we see the wonderfully varied forms of plant life, +and yet learn that, so to speak, each edifice is built with the same +kind of brick, called a cell, modified in form and function; when we see +the smallest and simplest equally with the largest and most complicated +plant increasing in size subject to the laws of growth by +intussusception and cell division, which are universal in the organic +world; we should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types. + +The first great generalization is into-- + +1. The vegetative type of reproduction, in which one or more ordinary +cells separate from the parent plant and become an independent plant; +and-- + +2. The special-cell type of reproduction, in which either one special +cell reproduces the plant, or two special cells by their union form the +origin of the new plant; these two modifications of the process are +known respectively as asexual and sexual. + +The third modification is a combination of the two others, namely, the +asexual special cell does not directly reproduce its parent form, but +gives rise to a structure in which sexual special cells are developed, +from whose coalescence springs again the likeness of the original plant. +This is termed alternation of generations. + +The sexual special cell is termed the _spore_. + +The sexual special cells are of one kind or of two kinds. + +Those which are of one kind may be termed, from their habit of yoking +themselves together, _zygoblasts_, or conjugating cells. + +Those which are of two kinds are, first, a generally aggressive and +motile fertilizing or so-called "male cell," called in its typical form +an _antherozoid_; and, second, a passive and motionless receptive or +so-called "female cell," called an _oosphere_. + +The product of the union of two zygoblasts is termed a _zygospore_. + +The product of the union of an antherozoid and an oosphere is termed an +_oospore_. + +In many cases the differentiation of the sexual cells does not proceed +so far as the formation of antherozoids or of distinct oospheres; these +cases I shall investigate with the others in detail presently. + +First, then, I will point out some of the modes of vegetative +reproduction. + +The commonest of these is cell division, as seen in unicellular plants, +such as protococcus, where the one cell which composes the plant simply +divides into two, and each newly formed cell is then a complete plant. + +The particular kind of cell division termed "budding" here deserves +mention. It is well seen in the yeast-plant, where the cell bulges at +one side, and this bulge becomes larger until it is nipped off from the +parent by contraction at the point of junction, and is then an +independent plant. + +Next, there is the process by which one plant becomes two by the dying +off of some connecting portion between two growing parts. + +Take, for instance, the case of the liverworts. In these there is a +thallus which starts from a central point and continually divides in a +forked or dichotomous manner. Now, if the central portion dies away, it +is obvious that there will be as many plants as there were forkings, and +the further the dying of the old end proceeds, the more young plants +will there be. + +Take again, among higher plants, the cases of suckers, runners, stolons, +offsets, etc. Here, by a process of growth but little removed from the +normal, portions of stems develop adventitious roots, and by the dying +away of the connecting links may become independent plants. + +Still another vegetative method of reproduction is that by bulbils or +gemmae. + +A bulbil is a bud which becomes an independent plant before it commences +to elongate; it is generally fleshy, somewhat after the manner of a +bulb, hence its name. Examples occur in the axillary buds of _Lilium +bulbiferum_, in some _Alliums_, etc. + +The gemma is found most frequently in the liverworts and mosses, and is +highly characteristic of these plants, in which indeed vegetative +reproduction maybe said to reach its fullest and most varied extent. + +Gemmae are here formed in a sort of flat cup, by division of superficial +cells of the thallus or of the stem, and they consist when mature of +flattened masses of cells, which lie loose in the cup, so that wind or +wet will carry them away on to soil or rock, when, either by direct +growth from apical cells, as with those of the liverworts, or with +previous emission of thread-like cells forming a "protonema," in the +case of the mosses, the young plant is produced from them. + +The lichens have a very peculiar method of gemmation. The lichen-thallus +is composed of chains or groups of round chlorophyl-containing cells, +called "gonidia," and masses of interwoven rows of elongated cells which +constitute the hyphae. Under certain conditions single cells of the +gonidia become surrounded with a dense felt of hyphae, these accumulate +in numbers below the surface of the thallus, until at last they break +out, are blown or washed away, and start germination by ordinary cell +division, and thus at once reproduce a fresh lichen-thallus. These +masses of cells are called soredia. + +Artificial budding and grafting do not enter into the scope of this +paper. + +As in the general growth and the vegetative reproduction of plants +cell-division is the chief method of cell formation, so in the +reproduction of plants by special cells the great feature is the part +played by cells which are produced not by the ordinary method of cell +division, but by one or the other processes of cell formation, namely, +free-cell formation or rejuvenescence. + +If we broaden somewhat the definition of rejuvenescence and free-cell +formation, and do not call the mother-cells of spores of mosses, higher +cryptogams, and also the mother-cells of pollen-grains, reproductive +cells, which strictly speaking they are not, but only producers of the +spores or pollen-grains, then we may say that _cell-division is confined +to vegetative processes, rejuvenescence and free-cell formation are +confined to reproductive processes_. + +Rejuvenescence may be defined as the rearrangement of the whole of the +protoplasm of a cell into a new cell, which becomes free from the +mother-cell, and may or may not secrete a cell-wall around it. + +If instead of the whole protoplasm of the cell arranging itself into one +mass, it divides into several, or if portions only of the protoplasm +become marked out into new cells, in each case accompanied by rounding +off and contraction, the new cells remaining free from one another, and +usually each secreting a cell wall, then this process, whose relation to +rejuvenescence is apparent, is called free-cell formation. + +The only case of purely vegetative cell-formation which takes place by +either of these processes is that of the formation of endosperm in +Selaginella and phanerogams, which is a process of free-cell formation. + +On the other hand, the universal contraction and rounding off of the +protoplasm, and the formation by either rejuvenescence or free-cell +formation, distinctly mark out the special or true reproductive cell. + +Examples of reproductive cells formed by rejuvenescence are: + +1. The swarm spores of many algae, as Stigeoclonium (figured in Sachs' +"Botany"). Here the contents of the cell contract, rearrange themselves, +and burst the side of the containing wall, becoming free as a +reproductive cell. + +2. The zygoblasts of conjugating algae, as in Spirogyra. Here the +contents of a cell contract and rearrange themselves only after contact +of the cell with one of another filament of the plant. This zygoblast +only becomes free after the process of conjugation, as described below. + +3. The oosphere of characeae, mosses and liverworts, and vascular +cryptogams, where in special structures produced by cell-divisions there +arise single primordial cells, which divide into two portions, of which +the upper portion dissolves or becomes mucilaginous, while the lower +contracts and rearranges itself to form the oosphere. + +4. Spores of mosses and liverworts, of vascular cryptogams, and pollen +cells of phanerogams, which are the analogue of the spores. + +The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes a +wall of its own, and by the bursting or absorption of the wall of its +mother-cell becomes free. This is evidently a rejuvenescence. + +Examples of reproductive cells formed by free-cell formation are: + +1. The ascospores of fungi and algae. + +2. The zoospores or mobile spores of many algae and fungi. + +3. The germinal vesicles of phanerogams. + +The next portion of my subject is the study of the methods by which +these special cells reproduce the plant. + +1st. Asexual methods. + +1. Rejuvenescence gives rise to a swarm-spore or zoospore. The whole of +the protoplasm of a cell contracts, becomes rounded and rearranged, and +escapes into the water, in which the plant floats as a mass of +protoplasm, clear at one end and provided with cilia by which it is +enabled to move, until after a time it comes to rest, and after +secreting a wall forms a new plant by ordinary cell-division. Example: +Oedogonium. + +2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya. + +3. Free-cell formation forms the typical motionless spore of algae and +fungi. For instance, in the asci of lichens there are formed from a +portion of the protoplasm four or more small ascospores, which secrete a +cell-wall and lie loose in the ascus. Occasionally these spores may +consist of two or more cells. They are set free by the rupture of the +ascus, and germinate by putting out through their walls one or more +filaments which branch and form the thallus of a new individual. Various +other spores formed in the same way are known as _tetraspores_, etc. + +4. Cell-division with rejuvenescence forms the spores of mosses and +higher cryptogams. + +To take the example of moss spores: + +Certain cells in the sporogonium of a moss are called mother-cells. The +protoplasm of each one of these becomes divided into four parts. Each of +these parts then secretes a cell-wall and becomes free as a spore by the +rupture or absorption of the wall of the mother-cell. The germination of +the spores I shall describe later. + +5. A process of budding which in the yeast plant and in mosses is merely +vegetatively reproductive, in fungi becomes truly reproductive, namely, +the buds are special cells arising from other special cells of the +hyphae. + +For example, the so-called "gills" of the common mushroom have their +surface composed of the ends of the threads of cells constituting the +hyphae. Some of these terminal cells push out a little finger of +protoplasm, which swells, thickens its wall, and becomes detached from +the mother-cell as a spore, here called specially a _basidiospore_. + +Also in the common gray mould of infusions and preserves, Penicillium, +by a process which is perhaps intermediate between budding and +cell-division, a cell at the end of a hypha constricts itself in several +places, and the constricted portions become separate as _conidiospores_. + +_Teleutospores, uredospores_, etc., are other names for spores similarly +formed. + +These conidiospores sometimes at once develop hyphae, and sometimes, as +in the case of the potato fungus, they turn out their contents as a +swarm-spore, which actively moves about and penetrates the potato leaves +through the stomata before they come to rest and elongate into the +hyphal form. + +So far for asexual methods of reproduction. + +I shall now consider the sexual methods. + +The distinctive character of these methods is that the cell from which +the new individual is derived is incapable of producing by division or +otherwise that new individual without the aid of the protoplasm of +another cell. + +Why this should be we do not know; all that we can do is to guess that +there is some physical or chemical want which is only supplied through +the union of the two protoplasmic masses. The process is of benefit to +the species to which the individuals belong, since it gives it a greater +vigor and adaptability to varying conditions, for the separate +peculiarities of two individuals due to climatic or other conditions are +in the new generation combined in one individual. + +The simplest of the sexual processes is conjugation. Here the two +combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union. + +Conjugation occurs in algae and fungi. A typical case is that of +Spirogyra. This is an alga with its cells in long filaments. Two +contiguous cells of two parallel filaments push each a little projection +from its cell-wall toward the other. When these meet, the protoplasm of +each of the two cells contracts, and assumes an elliptical form--it +undergoes rejuvenescence. Next an opening forms where the two cells are +in contact, and the contents of one cell pass over into the other, where +the two protoplasmic bodies coalesce, contract, and develop a cell-wall. +The zygospore thus formed germinates after a long period and forms a new +filament of cells. + +Another example of conjugation is that of Pandorina, an alga allied to +the well-known volvox. Here the conjugating cells swim free in water; +they have no cell-wall, and move actively by cilia. Two out of a number +approach, coalesce, contract, and secrete a cell-wall. After a long +period of rest, this zygospore allows the whole of its contents to +escape as a swarm-spore, which after a time secretes a gelatinous wall, +and by division reproduces the sixteen-celled family. + +We now come to fertilization, where the uniting cells are of two kinds. + +The simplest case is that of Vaucheria, an alga. Here the vegetative +filament puts out two protuberances, which become shut off from the body +of the filament by partitions. The protoplasm in one of these +protuberances arranges itself into a round mass--the oosphere or female +cell. The protoplasm of the other protuberance divides into many small +masses, furnished with cilia, the spermatozoids or male cells. Each +protuberance bursts, and some of the spermatozoids come in contact with +and are absorbed by the oosphere, which then secretes a cell-wall, and +after a time germinates. + +The most advanced type of fertilization is that of angiosperms. + +In them there are these differences from the above process: the contents +of the male cell, represented by the pollen, are not differentiated into +spermatozoids, and there is no actual contact between the contents of +the pollen tube and the germinal vesicle, but according to Strashurger, +there is a transference of the substance of the nucleus of the pollen +cell to that of the germinal vesicle by osmose. The coalescence of the +two nuclei within the substance of the germinal vesicle causes the +latter to secrete a wall, and to form a new plant by division, being +nourished the while by the mother plant, from whose tissues the young +embryo plant contained in the seed only becomes free when it is in an +advanced stage of differentiation. + +Perhaps the most remarkable cases of fertilization occur in the Florideae +or red seaweeds, to which class the well-known Irish moss belongs. + +Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, some +other cell which is quite distinct from the primarily fertilized cell +carries on the reproductive process. + +If the allied group of the Coleochaeteae is considered together with the +Florideae, we find a transition between the ordinary case of Coleochaete +and that of Dudresnaya. In Coleochaete, the male cell is a round +spermatozoid, and the female cell an oosphere contained in the base of a +cell which is elongated into an open and hair-like tube called the +trichogyne. The spermatozoid coalesces with the oosphere, which secretes +a wall, becomes surrounded with a covering of cells called a cystocarp, +which springs from cells below the trichogyne, and after the whole +structure falls from the parent plant, spores are developed from the +oospore, and from them arises a new generation. + +In Dudresnaya, on the other hand, the spermatozoid coalesces indeed with +the trichogyne, but this does not develop further. From below the +trichogyne, however, spring several branches, which run to the ends of +adjacent branches, with the apical cells of which they conjugate, and +the result of this conjugation is the development of a cystocarp similar +to that of Coleochaete. The remarkable point here is the way in which the +effect of the fertilizing process is carried from one cell to another +entirely distinct from it. + +Thus I have endeavored to sum up the processes of asexual and of sexual +reproduction. But it is a peculiar characteristic of most classes of +plants that the cycle of their existence is not complete until both +methods of reproduction have been called into play, and that the +structure produced by one method is entirely different from that +produced by the other method. + +Indeed, it is only in some algae and fungi that the reproductive cells of +one generation produce a generation similar to the parent; in all other +plants a generation A produces are unlike generation B, which may either +go on to produce another generation, C, and then back to A, or it may go +on producing B's until one of these reproduces A, or again it may +directly reproduce; A. Thus we have the three types: + + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. + +The first case is not common, the usual number of generations being two +only; but a typical example of the occurrence of three generations is in +such fungi as _Puccinia Graminis_. Here the first generation grows on +barberry leaves, and produces a kind of spore called an _aecidium spore_. +These aecidium spores germinate only on a grass stem or leaf, and a +distinct generation is produced, having a particular kind of spore +called an _uredospore_. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation with +another kind of spore, called a _teleutospore_, is produced. + +The teleutospores only germinate on barberry leaves, and there reproduce +the original aecidium generation. + +Thus we have the series A.B.B.B ... BCA + +In this instance all the generations are asexual, but the most common +case is for the sexual and the asexual generations to alternate. I will +describe as examples the reproduction of a moss, a fern, and a +dicotyledon. + +In such a typical moss as Funaria, we have the following cycle of +developments: The sexual generation is a dioecious leafy structure, +having a central elongated axis, with leaves arranged regularly around +and along it. At the top of the axis in the male plant rise the +antheridia, surrounded by an envelope of modified leaves called the +perigonium. The antheridia are stalked sacs, with a single wall of +cells, and the spiral antherozoids arise by free-cell formation from the +cells of the interior. They are discharged by the bursting of the +antheridium, together with a mucilage formed of the degraded walls of +their mother cells. + +In the female plant there arise at the apex of the stem, surrounded by +an envelope of ordinary leaves, several archegonia. These are of the +ordinary type of those organs, namely, a broad lower portion, containing +a naked oosphere and a long narrow neck with a central canal leading to +the oosphere. Down this canal pass one or more antherozoids, which +become absorbed into the oosphere, and this then secretes a wall, and +from it grows the second or asexual generation. The peculiarity of this +asexual or spore-bearing plant is that it is parasitic on the sexual +plant; the two generations, although not organically connected, yet +remain in close contact, and the spore-bearing generation is at all +events for a time nourished by the leafy sexual generation. + +The spore-bearing generation consists of a long stalk, closely held +below by the cells of the base of the archegonium; this supports a +broadened portion which contains the spores, and the top is covered with +the remains of the neck of the archegonium forming the calyptra. + +The spores arise from special or mother-cells by a process of division, +or it may be even termed free-cell formation, the protoplasm of each +mother-cell dividing into four parts, each of which contracts, secretes +a wall, and thus by rejuvenescence becomes a spore, and by the +absorption of the mother-cells the spores lie loose in the spore sac. +The spores are set free by the bursting of their chamber, and each +germinates, putting out a branched thread of cells called a protonema, +which may perhaps properly be termed a third generation in the cycle of +the plant; for it is only from buds developed on this protonema that the +leafy sexual plant arises. + +The characteristics, then, of the mosses are, that the sexual generation +is leafy, the one or two asexual generations are thalloid, and that the +spore-bearing generation is in parasitic connection with the sexual +generation. + +In the case of the fern, these conditions are very different. + +The sexual generation is a small green thalloid structure called a +prothallium, which bears antheridia and archegonia, each archegonium +having a neck-canal and oosphere, which is fertilized just as in the +moss. + +But the asexual generation derived from the oospore only for a short +while remains in connection with the prothallium, which, of course, +answers to the leafy portion of the moss. What is generally known as the +fern is this asexual generation, a great contrast to the small leafless +moss fruit or sporogonium as it is called, to which it is +morphologically equivalent. On the leaves of this generation arise the +sporangia which contain the spores. The spores are formed in a manner +very similar to those of the mosses, and are set free by rupture of the +sporangium. + +The spore produces the small green prothallium by cell-division in the +usual way, and this completes the cycle of fern life. + +The alternation of generations, which is perhaps most clear and typical +in the case of the fern, becomes less distinctly marked in the plants of +higher organization and type. + +Thus in the Rhizocarpae there are two kinds of spores, _microspores_ and +_macrospores_, producing prothallia which bear respectively antheridia +and archegonia; in the Lycopodiaceae, the two kinds of spores produce +very rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the endosperm, in +which archegonia or corpuscula are formed; and lastly, in typical +dicotyledons it is only lately that any trace of a prothallium from the +microspore or pollen cell has been discovered, while the macrospore or +embryo-sac produces only two or three prothallium cells, known as +antipodal cells, and two or three oospheres, known as germinal vesicles. + +This description of the analogies of the pollen and embryo-sac of +dicotyledons assumes that the general vegetative structure of this class +of plants is equivalent to the asexual generation of the higher +cryptogams. In describing their cycle of reproduction I will endeavor to +show grounds for this assumption. + +We start with the embryo as contained in the seed. This embryo is the +product of fertilization of a germinal vesicle by a pollen tube. Hence, +by analogy with the product of fertilization of rhizocarp's, ferns, and +mosses, it should develop into a spore bearing plant. It does develop +into a plant in which on certain modified leaves are produced masses of +tissue in which two kinds of special reproductive cells are formed. This +is precisely analogous to the case of gymnosperms, lycopods, etc., where +on leaf structures are formed macro and micro sporangia. + +To deal first with the microsporangium or pollen-sac. The pollen cells +are formed from mother cells by a process of cell division and +subsequent setting free of the daughter cells or pollen cells by +rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceae, etc. The subsequent +behavior of the pollen cell, its division and its fertilization of the +germinal vesicle or oosphere, leave no doubt as to its analogy with the +microspore of vascular cryptogams. + +Secondly, the nucleus of the ovule corresponds with the macrosporangium +of Selaginella, through the connecting link of the conifers, where the +ovule is of similar origin and position to the macrosporangium of the +Lycopodiaceae. But the formation of the macrospore or embryo-sac is +simpler than the corresponding process in cryptogams. It arises by a +simple enlargement of one cell of the nucleus instead of by the division +of one cell into four, each thus becoming a macrospore. At the top of +this macrospore or embryo-sac two or three germinal vesicles are formed +by free cell formation, and also two or three cells called antipodal +cells, since they travel to the other end of the embryo-sac; these +latter represent a rudimentary prothallium. This formation of germinal +vesicles and prothallium seems very different from the formation of +archegonia and prothallium in Selaginella, for instance; but the link +which connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed. + +Thus we see that the flowering plant is essentially the equivalent of +the asexual fern, and of the sporogonium of the moss, and the pollen +cell and the embryo-sac represent the two spores of the higher +cryptogams, and the pollen tube and the germinal vesicles and antipodal +cells are all that remain of the sexual generation, seen in the moss as +a leafy plant, and in the fern as a prothallium. Indeed, when a plant +has monoecious or dioecious flowers, the distinction between the asexual +and the sexual generation has practically been lost, and the +spore-bearing generation has become identified with the sexual +generation. + +Having now described the formation of the pollen and the germinal +vesicles, it only remains to show how they form the embryo. The pollen +cell forms two or three divisions, which are either permanent or soon +absorbed; this, as before stated, is the rudimentary male prothallium. +Then when it lies on the stigma it develops a long tube, which passes +down the style and through the micropyle of the ovule to the germinal +vesicles, one of which is fertilized by what is probably an osmotic +transference of nuclear matter. The germinal vesicle now secretes a +wall, divides into two parts, and while the rest of the embyro-sac fills +with endosperm cells, it produces by cell division from the upper half a +short row of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or leafy +plant, and while in the fern each generation is an independent +structure, here in the dicotyledon, on the other hand, the asexual +generation or embryo is again for a time nourished in the interior of +the embryo-sac representing the sexual generation, and this again +derives its nourishment from the previous asexual generation, so that as +in the moss, there is again a partial parasitism of one generation on +the other. + +To sum up the methods of plant reproduction: They resolve themselves +into two classes. + +1st. Purely vegetative. + +2d. Truly reproductive by special cells. + +In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive methods. + +1st. Reproduction from an asexual spore. + +2d. Reproduction from an oospore formed by the combination of two sexual +cells. + +In the vast majority of plant species these two types are used by the +individuals alternately. + +The extraordinary similarity of the reproductive process, as shown in +the examples I have given, Achlya, Spirogyra, and Vaucheria among algae, +the moss, the fern, and the flowering plant, a similarity which becomes +the more marked the more the details of each case and of the cases of +plants which form links between these great classes are studied, points +to a community of origin of all plants in some few or one primeval +ancestor. And to this inference the study of plant structure and +morphology, together with the evidence of palaeobotany among other +circumstances, lends confirmatory evidence, and all modern discoveries, +as for instance that of the rudimentary prothallium formed by the pollen +of angiosperms, tend to the smoothing of the path by which the descent +of the higher plants from simpler types will, as I think, be eventually +shown. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +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. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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Anyone seeking to utilize +this eBook outside of the United States should confirm copyright +status under the laws that apply to them. diff --git a/README.md b/README.md new file mode 100644 index 0000000..92f0631 --- /dev/null +++ b/README.md @@ -0,0 +1,2 @@ +Project Gutenberg (https://www.gutenberg.org) public repository for +eBook #11383 (https://www.gutenberg.org/ebooks/11383) diff --git a/old/11383-8.txt b/old/11383-8.txt new file mode 100644 index 0000000..6e2e931 --- /dev/null +++ b/old/11383-8.txt @@ -0,0 +1,4672 @@ +The Project Gutenberg EBook of Scientific American Supplement, Vol. XXI., +No. 531, March 6, 1886, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, Vol. XXI., No. 531, March 6, 1886 + +Author: Various + +Release Date: February 29, 2004 [EBook #11383] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPP. 531 *** + + + + +Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland, +Charles Franks and the DP Team + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 531 + + + + +NEW YORK, MARCH 6, 1886 + +Scientific American Supplement. Vol. XXI, No. 531. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY AND METALLURGY.--Annatto.-Analyses of the same.--By + WM. LAWSON + + Aluminum.--By J.A. PRICE.--Iron the basis of civilization.-- + Aluminum the metal of the future.--Discovery of aluminum.--Art + of obtaining the metal.--Uses and possibilities + +II. ENGINEERING AND MECHANICS.--The Use of Iron in Fortification. + --Armor-plated casements.--The Schumann-Gruson chilled iron + cupola.--Mougin's rolled iron cupola.--With full page + of engravings + + High Speed on the Ocean + + Sibley College Lectures.--Principles and Methods of Balancing + Forces developed in Moving Bodies.--Momentum and centrifugal + force.--By CHAS.T. PORTER.--3 figures + + Compressed Air Power Schemes.--By J. STURGEON.--Several + figures + + The Berthon Collapsible Canoe.--2 engravings + + The Fiftieth Anniversary of the Opening of the First German + Steam Railroad.--With full page engraving + + Improved Coal Elevator.--With engraving + +III. TECHNOLOGY.--Steel-making Ladles.--4 figures + + Water Gas.--The relative value of water gas and other gases as + Iron-reducing Agents.--By B.H. THWAITE.--Experiments.--With + tables and 1 figure + + Japanese Rice Wine and Soja Sauce.--Method of making + +IV. ELECTRICITY, MICROSCOPY, ETC.-Apparatus for demonstrating + that Electricity develops only on the Surface of Conductors.--1 + figure + + The Colson Telephone.--3 engravings + + The Meldometer.--An apparatus for determining the melting + points of minerals + + Touch Transmission by Electricity in the Education of Deaf + Mutes.--By S. TEFFT WALKER.--With 1 figure + +V. HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By + C.F. HOLDER.--With 2 engravings + + How Plants are reproduced.--By C.E. STUART.--A paper read + before the Chemists' Assistants' Association + +VI. MISCELLANEOUS--The Origin of Meteorites.--With 1 figure + + * * * * * + + + + +THE USE OF IRON IN FORTIFICATION. + + +Roumania is thinking of protecting a portion of the artillery of the +forts surrounding her capital by metallic cupolas. But, before deciding +upon the mode of constructing these formidable and costly affairs, and +before ordering them, she has desired to ascertain their efficacy and +the respective merits of the chilled iron armor which was recently in +fashion and of rolled iron, which looks as if it were to be the fashion +hereafter. + +[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.] + +The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a turret +of rolled iron. Both of these recommend themselves by various merits, +and by remarkably ingenious arrangements, and it only remains to be seen +how they will behave under the fire of the largest pieces of artillery. + +[Illustration: FIG. 2.] + +We are far in advance of the time when cannons with smooth bore were +obliged to approach to within a very short range of a scarp in order to +open a breach, and we are far beyond that first rifled artillery which +effected so great a revolution in tactics. + +[Illustration: FIG. 3.] + +To-day we station the batteries that are to tear open a rampart at +distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch +cannon that arms them has for probable deviations, under a charge of 20 +pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16 +inches in direct fire and 8 inches in curved. + +The weight of the projectile is 88 pounds, and its remanent velocity at +the moment of impact is 1,295 feet. Under this enormous live force, the +masonry gradually crumbles, and carries along the earth of the parapet, +and opens a breach for the assaulting columns. + +[Illustration: FIG. 4--STATE OF A CUPOLA AFTER THE ACTION OF +THIRTY-SEVEN 6 IN. PROJECTILES.] + +In order to protect the masonry of the scarp, engineers first lowered +the cordon to the level of the covert-way. Under these circumstances, +the enemy, although he could no longer see it, reached it by a curved or +"plunging" shot. When, in fact, for a given distance we load a gun with +the heaviest charge that it will stand, the trajectory, AMB (Fig. 2), is +as depressed as possible, and the angles, a and a', at the start and +arrival are small, and we have a direct shot. If we raise the chase of +the piece, the projectile will describe a curve in space which would be +a perfect parabola were it not for the resistance of the air, and the +summit of such curve will rise in proportion as the angle so increases. +So long as the falling angle, a, remains less than 45°, we shall have a +curved shot. When the angle exceeds this, the shot is called "vertical." +If we preserve the same charge, the parabolic curve in rising will meet +the horizontal plane at a greater distance off. This is, as well known, +the process employed for reaching more and more distant objects. + +[Illustration: Fig. 5.--STATE OF A CAST-IRON CUPOLA AFTER THE BREAKAGE +OF A VOUSSOIR.] + +The length of a gun depends upon the maximum charge burned in it, since +the combustion must be complete when the projectile reaches the open +air. It results from this that although guns of great length are capable +of throwing projectiles with small charges, it is possible to use +shorter pieces for this purpose--such as howitzers for curved shots and +mortars for vertical ones. The curved shot finds one application in the +opening of breaches in scarp walls, despite the existence of a covering +of great thickness. If, from a point, a (Fig. 3), we wish to strike the +point, b, of a scarp, over the crest, c, of the covert-way, it will +suffice to pass a parabolic curve through these three points--the +unknown data of the problem, and the charge necessary, being +ascertained, for any given piece, from the artillery tables. In such +cases it is necessary to ascertain the velocity at the impact, since the +force of penetration depends upon the live force (mv²) of the +projectile, and the latter will not penetrate masonry unless it have +sufficient remanent velocity. Live force, however, is not the sole +factor that intervenes, for it is indispensable to consider the angle at +which the projectile strikes the wall. Modern guns, such as the Krupp 6 +inch and De Bange 6 and 8 inch, make a breach, the two former at a +falling angle of 22°, and the latter at one of 30°. It is not easy to +lower the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass of the +glacis. + +The same guns are employed for dismounting the defender's pieces, which +he covers as much as possible behind the parapet. Heavy howitzers +destroy the _materiel_, while shrapnel, falling nearly vertically, and +bursting among the men, render all operations impossible upon an open +terre-plein. + +[Illustration: FIG. 6.--STATE OF A CHILLED IRON CUPOLA BROKEN BY A 12 +INCH BALL.] + +The effect of 6 and 8 inch rifled mortars is remarkable. The Germans +have a 9 inch one that weighs 3,850 pounds, and the projectile of which +weighs 300. But French mortars in nowise cede to those of their +neighbors; Col. De Bange, for example, has constructed a 10½ inch one of +wonderful power and accuracy. + +Seeing the destructive power of these modern engines of war, it may well +be asked how many pieces the defense will be able to preserve intact for +the last period of a siege--for the very moment at which it has most +need of a few guns to hold the assailants in check and destroy the +assaulting columns. Engineers have proposed two methods of protecting +these few indispensable pieces. The first of these consists in placing +each gun under a masonry vault, which is covered with earth on all sides +except the one that contains the embrasure, this side being covered with +armor plate. + +The second consists in placing one or two guns under a metallic cupola, +the embrasures in which are as small as possible. The cannon, in a +vertical aim, revolves around the center of an aperture which may be of +very small dimensions. As regards direct aim, the carriages are +absolutely fixed to the cupola, which itself revolves around a vertical +axis. These cupolas may be struck in three different ways: (1) at right +angles, by a direct shot, and consequently with a full charge--very +dangerous blows, that necessitate a great thickness of the armor plate; +(2) obliquely, when the projectile, if the normal component of its real +velocity is not sufficient to make it penetrate, will be deflected +without doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy. + +General Brialmont says that the metal of the cupola should be able to +withstand both penetration and breakage; but these two conditions +unfortunately require opposite qualities. A metal of sufficient +ductility to withstand breakage is easily penetrated, and, conversely, +one that is hard and does not permit of penetration does not resist +shocks well. Up to the present, casehardened iron (Gruson) has appeared +to best satisfy the contradictory conditions of the problem. Upon the +tempered exterior of this, projectiles of chilled iron and cast steel +break upon striking, absorbing a part of their live force for their own +breakage. + +In 1875 Commandant Mougin performed some experiments with a chilled iron +turret established after these plans. The thickness of the metal +normally to the blows was 23½ inches, and the projectiles were of cast +steel. The trial consisted in firing two solid 12 in. navy projectiles, +46 cylindrical 6 in. ones, weighing 100 lb., and 129 solid, pointed +ones, 12 in. in diameter. The 6 inch projectiles were fired from a +distance of 3,280 feet, with a remanent velocity of 1,300 feet. The +different phases of the experiment are shown in Figs. 4, 5, and 6. The +cupola was broken; but it is to be remarked that a movable and +well-covered one would not have been placed under so disadvantageous +circumstances as the one under consideration, upon which it was easy to +superpose the blows. An endeavor was next made to substitute a tougher +metal for casehardened iron, and steel was naturally thought of. But +hammered steel broke likewise, and a mixed or compound metal was still +less successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was rolled +iron. Armor plate composed of this latter has been submitted to several +tests, which appear to show that a thickness of 18 inches will serve as +a sufficient barrier to the shots of any gun that an enemy can +conveniently bring into the field. + +[Illustration: FIG. 7.--CASEMATE OF CHILLED IRON AFTER RECEIVING +NINETY-SIX SHOTS.] + +_Armor Plated Casemates_.--Fig. 7 shows the state of a chilled iron +casemate after a vigorous firing. The system that we are about to +describe is much better, and is due to Commandant Mougin. + +[Illustration: FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.] + +The gun is placed under a vault whose generatrices are at right angles +to the line of fire (Fig. 8), and which contains a niche that traverses +the parapet. This niche is of concrete, and its walls in the vicinity of +the embrasure are protected by thick iron plate. The rectangular armor +plate of rolled iron rests against an elastic cushion of sand compactly +rammed into an iron plate caisson. The conical embrasure traverses this +cushion by means of a cast-steel piece firmly bolted to the caisson, and +applied to the armor through the intermedium of a leaden ring. +Externally, the cheeks of the embrasure and the merlons consist of +blocks of concrete held in caissons of strong iron plate. The +surrounding earthwork is of sand. For closing the embrasure, Commandant +Mougin provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected by +the sloping mass of concrete that covers the head of the casemate. A +windlass and chain give the disk the motion that brings one of its +apertures opposite the embrasure or that closes the latter. When this +portion of the disk has suffered too much from the enemy's fire, a +simple maneuver gives it a half revolution, and the second aperture is +then made use of. + +_The Schumann-Gruson Chilled Iron Cupola_.--This cupola (Fig. 9) is +dome-shaped, and thus offers but little surface to direct fire; but it +can be struck by a vertical shot, and it may be inquired whether its top +can withstand the shock of projectiles from a 10 inch rifled mortar. It +is designed for two 6 inch guns placed parallel. Its internal diameter +is 19½ feet, and the dome is 8 inches in thickness and has a radius of +16½ feet. It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of relatively +small bulk--a bad feature as regards resistance to shock. To obviate +this difficulty, the inventor partitions it internally in such a way as +to leave only sufficient space to maneuver the guns. The partitions +consist of iron plate boxes filled with concrete. The form of the dome +has one inconvenience, viz., the embrasure in it is necessarily very +oblique, and offers quite an elongated ellipse to blows, and the edges +of the bevel upon a portion of the circumference are not strong enough. +In order to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides of +the embrasure. The motion of the piece necessary to aim it vertically is +effected around this axis of rotation. The weight of the gun is balanced +by a system of counterpoises and the chains, l, and the breech +terminates in a hollow screw, f, and a nut, g, held between two +directing sectors, h. The cupola is revolved by simply acting upon the +rollers. + +[Illustration: FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.] + +_Mougin's Rolled Iron Cupola_.--The general form of this cupola (Fig. 1) +is that of a cylindrical turret. It is 12¾ feet in diameter, and rises +3¼ feet above the top of the glacis. It has an advantage over the one +just described in possessing more internal space, without having so +large a diameter; and, as the embrasures are at right angles with the +sides, the plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of strong +iron plate strengthened by angle irons. Vertical partitions under the +cheeks of the gun carriages serve as cross braces, and are connected +with each other upon the table of the hydraulic pivot around which the +entire affair revolves. This pivot terminates in a plunger that enters a +strong steel press-cylinder embedded in the masonry of the lower +concrete vault. + +The iron plate ring carries wheels and rollers, through the intermedium +of which the turret is revolved. The circular iron track over which +these move is independent of the outer armor. + +The whole is maneuvered through the action of one man upon the piston of +a very small hydraulic press. The guns are mounted upon hydraulic +carriages. The brake that limits the recoil consists of two bronze pump +chambers, a and b (Fig. 10). The former of these is 4 inches in +diameter, and its piston is connected with the gun, while the other is 8 +inches in diameter, and its piston is connected with two rows of 26 +couples of Belleville springs, d. The two cylinders communicate through +a check valve. + +When the gun is in battery, the liquid fills the chamber of the 4 inch +pump, while the piston of the 8 inch one is at the end of its stroke. A +recoil has the effect of driving in the 4 inch piston and forcing the +liquid into the other chamber, whose piston compresses the springs. At +the end of the recoil, the gunner has only to act upon the valve by +means of a hand-wheel in order to bring the gun into battery as slowly +as he desires, through the action of the springs. + +[Illustration: FIG. 10.--MOUGIN'S HYDRAULIC GUN CARRIAGE.] + +For high aiming, the gun and the movable part of its carriage are +capable of revolving around a strong pin, c, so placed that the axis of +the piece always passes very near the center of the embrasure, thus +permitting of giving the latter minimum dimensions. The chamber of the 8 +inch pump is provided with projections that slide between circular +guides, and carries the strap of a small hydraulic piston, p, that +suffices to move the entire affair in a vertical plane, the gun and +movable carriage being balanced by a counterpoise, q. + +The projectiles are hoisted to the breech of the gun by a crane. + +Between the outer armor and turret sufficient space is left for a man to +enter, in order to make repairs when necessary. + +Each of the rolled iron plates of which the turret consists weighs 19 +tons. The cupolas that we have examined in this article have been +constructed on the hypothesis than an enemy will not be able to bring +into the field guns of much greater caliber than 6 inches.--_Le Genie +Civil_. + + * * * * * + + + + +HIGH SPEED ON THE OCEAN. + + +_To the Editor of the Scientific American_: + +Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN of +Jan. 2, 1886, in regard to high speed on the ocean. + +Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the plane +of their motion, but at an angle to it, the same principle would, if +applied to a steamship, increase its speed. But let us look at the +subject from another standpoint. The quadruped has to support the weight +of his body, and propel himself forward, with the same force. If the +force be applied perpendicularly, the body is elevated, but not moved +forward. If the force is applied horizontally, the body moves forward, +but soon falls to the ground, because it is not supported. But when the +force is applied at the proper angle, the body is moved forward and at +the same time supported. Directly contrary to Capt. Giles' theory, the +greater the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and _vice versa_. This may +easily be seen by any one watching the motions of the horse, hound, +deer, rabbit, etc., when in rapid motion. The water birds and animals, +whose weight is supported by the water, do not exert the propulsive +force in a downward direction, but in a direct line with the plane of +their motion. The man who swims does not increase his motion by kicking +out at an angle, but by drawing the feet together with the legs +straight, thus using the water between them as a double inclined plane, +on which his feet and legs slide and thus increase his motion. The +weight of the steamship is already supported by the water, and all that +is required of the propeller is to push her forward. If set so as to act +in a direct line with the plane of motion, it will use all its force to +push her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. If +placed at an angle of 45° with the plane of motion, half the force will +be used in raising the ship out of the water, and only half will be left +to push her forward. + +ENOS M. RICKER. + +Park Rapids, Minn., Jan. 23, 1886. + + * * * * * + + + + +SIBLEY COLLEGE LECTURES. + +BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING. + + + + +PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING BODIES. + +BY CHAS. T. PORTER. + +INTRODUCTION. + + +On appearing for the first time before this Association, which, as I am +informed, comprises the faculty and the entire body of students of the +Sibley College of Mechanical Engineering and the Mechanic Arts, a +reminiscence of the founder of this College suggests itself to me, in +the relation of which I beg first to be indulged. + +In the years 1847-8-9 I lived in Rochester, N.Y., and formed a slight +acquaintance with Mr. Sibley, whose home was then, as it has ever since +been, in that city. Nearly twelve years afterward, in the summer of +1861, which will be remembered as the first year of our civil war, I met +Mr. Sibley again. We happened to occupy a seat together in a car from +New York to Albany. He recollected me, and we had a conversation which +made a lasting impression on my memory. I said we had a conversation. +That reminds me of a story told by my dear friend, of precious memory, +Alexander L. Holley. One summer Mr. Holley accompanied a party of +artists on an excursion to Mt. Katahdin, which, as you know, rises in +almost solitary grandeur amid the forests and lakes of Maine. He wrote, +in his inimitably happy style, an account of this excursion, which +appeared some time after in _Scribner's Monthly_, elegantly illustrated +with views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. Katahdin. +"That is," he explained, "Mr. Church painted, and I held the umbrella." + +This describes the conversation which Mr. Sibley and I had. Mr. Sibley +talked, and I listened. He was a good talker, and I flatter myself that +I rather excel as a listener. On that occasion I did my best, for I knew +whom I was listening to. I was listening to the man who combined bold +and comprehensive grasp of thought, unerring foresight and sagacity, and +energy of action and power of accomplishment, in a degree not surpassed, +if it was equaled, among men. + +Some years before, Mr. Sibley had created the Western Union Telegraph +Company. At that time telegraphy was in a very depressed state. The +country was to a considerable extent occupied by local lines, chartered +under various State laws, and operated without concert. Four rival +companies, organized under the Morse, the Bain, the House, and the +Hughes patents, competed for the business. Telegraph stock was nearly +valueless. Hiram Sibley, a man of the people, a resident of an inland +city, of only moderate fortune, alone grasped the situation. He saw that +the nature of the business, and the demands of the country, alike +required that a single organization, in which all interests should be +combined, should cover the entire land with its network, by means of +which every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this vividly, +and realized it with the most intense earnestness of conviction. With +Mr. Sibley, to be convinced was to act; and so he set about the task of +carrying this vast scheme into execution. The result is well known. By +his immense energy, the magnetic power with which he infused his own +convictions into other minds, the direct, practical way in which he set +about the work, and his indomitable perseverance, Mr. Sibley attained at +last a phenomenal success. + +But he was not then telling me anything about this. He was telling me of +the construction of the telegraph line to the Pacific Coast. Here again +Mr. Sibley had seen that which was hidden from others. This case +differed from the former one in two important respects. Then Mr. Sibley +had been dependent on the aid and co-operation of many persons; and this +he had been able to secure. Now, he could not obtain help from a human +being; but he had become able to act independently of any assistance. + +He had made a careful study of the subject, in his thoroughly practical +way, and had become convinced that such a line was feasible, and would +be remunerative. At his instance a convention of telegraph men met in +the city of New York, to consider the project. The feeling in this +convention was extremely unfavorable to it. A committee reported against +it unanimously, on three grounds--the country was destitute of timber, +the line would be destroyed by the Indians, and if constructed and +maintained, it would not pay expenses. Mr. Sibley found himself alone. +An earnest appeal which he made from the report of the committee was +received with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and two +thousand miles of its breadth by bands of savages, who of course would +destroy the line as soon as it was put up, and where repairs would be +difficult and useless, even if the other objections to it were out of +the way, struck the members of the convention as so exquisitely +ludicrous that it seemed as if they would never be done laughing about +it. If Mr. Sibley had advocated a line to the moon, they would hardly +have seen in it greater evidence of lunacy. When he could be heard, he +rose again and said: "Gentlemen, you may laugh, but if I was not so old, +I would build the line myself." Upon this, of course, they laughed +louder than ever. As they laughed, he grew mad, and shouted: "Gentlemen, +I will bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon it +scouted the project as chimerical, and no capitalist would put a dollar +in it, Hiram Sibley built the line of telegraph to San Francisco, +risking in it all he had in the world. He set about the work with his +customary energy, all obstacles vanished, and the line was completed in +an incredibly short time. And from the day it was opened, it has proved +probably the most profitable line of telegraph that has ever been +constructed. There was the practicability, and there was the demand and +the business to be done, and yet no living man could see it, or could be +made to see it, except Hiram Sibley. "And to-day," he said, with honest +pride, "to-day in New York, men to whom I went almost on my knees for +help in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one." + +"But how about the Indians?" I asked. "Why," he replied, "we never had +any trouble from the Indians. I knew we wouldn't have. Men who supposed +I was such a fool as to go about this undertaking before that was all +settled didn't know me. No Indian ever harmed that line. The Indians are +the best friends we have got. You see, we taught the Indians the Great +Spirit was in that line; and what was more, we proved it to them. It +was, by all odds, the greatest medicine they ever saw. They fairly +worshiped it. No Indian ever dared to do it harm." + +"But," he added, "there was one thing I didn't count on. The border +ruffians in Missouri are as bad as anybody ever feared the Indians might +be. They have given us so much trouble that we are now building a line +around that State, through Iowa and Nebraska. We are obliged to do it." + +This opened another phase of the subject. The telegraph line to the +Pacific had a value beyond that which could be expressed in money. It +was perhaps the strongest of all the ties which bound California so +securely to the Union, in the dark days of its struggle for existence. +The secession element in Missouri recognized the importance of the line +in this respect, and were persistent in their efforts to destroy it. We +have seen by what means their purpose was thwarted. + +I have always felt that, among the countless evidences of the ordering +of Providence by which the war for the preservation of the Union was +signalized, not the least striking was the raising up of this remarkable +man, to accomplish alone, and in the very nick of time, a work which at +once became of such national importance. + +This is the man who has crowned his useful career, and shown again his +eminently practical character and wise foresight, by the endowment of +this College, which cannot fail to be a perennial source of benefit to +the country whose interests he has done so much to promote, and which +his remarkable sagacity and energy contributed so much to preserve. + +We have an excellent rule, followed by all successful designers of +machinery, which is, to make provision for the extreme case, for the +most severe test to which, under normal conditions, and so far as +practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than the +extreme demand are not likely to give trouble. I shall apply this +principle in addressing you to-day. In what I have to say, I shall speak +directly to the youngest and least advanced minds among my auditors. If +I am successful in making an exposition of my subject which shall be +plain to them, then it is evident that I need not concern myself about +being understood by the higher class men and the professors. + +The subject to which your attention is now invited is + + +THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES. + +This is a subject with which every one who expects to be concerned with +machinery, either as designer or constructor, ought to be familiar. The +principles which underlie it are very simple, but in order to be of use, +these need to be thoroughly understood. If they have once been mastered, +made familiar, incorporated into your intellectual being, so as to be +readily and naturally applied to every case as it arises, then you +occupy a high vantage ground. In this particular, at least, you will not +go about your work uncertainly, trying first this method and then that +one, or leaving errors to be disclosed when too late to remedy them. On +the contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what you +intend. + +Moreover, when you read discussions on any branch of this subject, you +will not receive these into unprepared minds, just as apt to admit error +as truth, and possessing no test by which to distinguish the one from +the other; but you will be able to form intelligent judgments with +respect to them. You will discover at once whether or not the writers +are anchored to the sure holding ground of sound principles. + +It is to be observed that I do not speak of balancing bodies, but of +balancing forces. Forces are the realities with which, as mechanical +engineers, you will have directly to deal, all through your lives. The +present discussion is limited also to those forces which are developed +in moving bodies, or by the motion of bodies. This limitation excludes +the force of gravity, which acts on all bodies alike, whether at rest or +in motion. It is, indeed, often desirable to neutralize the effect of +gravity on machinery. The methods of doing this are, however, obvious, +and I shall not further refer to them. + +Two very different forces, or manifestations of force, are developed by +the motion of bodies. These are + + +MOMENTUM AND CENTRIFUGAL FORCE. + +The first of these forces is exerted by every moving body, whatever the +nature of the path in which it is moving, and always in the direction of +its motion. The latter force is exerted only by bodies whose path is a +circle, or a curve of some form, about a central body or point, to which +it is held, and this force is always at right angles with the direction +of motion of the body. + +Respecting momentum, I wish only to call your attention to a single +fact, which will become of importance in the course of our discussion. +Experiments on falling bodies, as well as all experience, show that the +velocity of every moving body is the product of two factors, which must +combine to produce it. Those factors are force and distance. In order to +impart motion to the body, force must act through distance. These two +factors may be combined in any proportions whatever. The velocity +imparted to the body will vary as the square root of their product. +Thus, in the case of any given body, + + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. + +This table might be continued indefinitely. The product of the force +into the distance will always vary as the square of the final velocity +imparted. To arrest a given velocity, the same force, acting through the +same distance, or the same product of force into distance, is required +that was required to impart the velocity. + +The fundamental truth which I now wish to impress upon your minds is +that in order to impart velocity to a body, to develop the energy which +is possessed by a body in motion, force must act through distance. +Distance is a factor as essential as force. Infinite force could not +impart to a body the least velocity, could not develop the least energy, +without acting through distance. + +This exposition of the nature of momentum is sufficient for my present +purpose. I shall have occasion to apply it later on, and to describe the +methods of balancing this force, in those cases in which it becomes +necessary or desirable to do so. At present I will proceed to consider +the second of the forces, or manifestations of force, which are +developed in moving bodies--_centrifugal force_. + +This force presents its claims to attention in all bodies which revolve +about fixed centers, and sometimes these claims are presented with a +good deal of urgency. At the same time, there is probably no subject, +about which the ideas of men generally are more vague and confused. This +confusion is directly due to the vague manner in which the subject of +centrifugal force is treated, even by our best writers. As would then +naturally be expected, the definitions of it commonly found in our +handbooks are generally indefinite, or misleading, or even absolutely +untrue. + +Before we can intelligently consider the principles and methods of +balancing this force, we must get a correct conception of the nature of +the force itself. What, then, is centrifugal force? It is an extremely +simple thing; a very ordinary amount of mechanical intelligence is +sufficient to enable one to form a correct and clear idea of it. This +fact renders it all the more surprising that such inaccurate and +confused language should be employed in its definition. Respecting +writers, also, who use language with precision, and who are profound +masters of this subject, it must be said that, if it had been their +purpose to shroud centrifugal force in mystery, they could hardly have +accomplished this purpose more effectually than they have done, to minds +by whom it was not already well understood. + +Let us suppose a body to be moving in a circular path, around a center +to which it is firmly held; and let us, moreover, suppose the impelling +force, by which the body was put in motion, to have ceased; and, also, +that the body encounters no resistance to its motion. It is then, by our +supposition, moving in its circular path with a uniform velocity, +neither accelerated nor retarded. Under these conditions, what is the +force which is being exerted on this body? Clearly, there is only one +such force, and that is, the force which holds it to the center, and +compels it, in its uniform motion, to maintain a fixed distance from +this center. This is what is termed centripetal force. It is obvious, +that the centripetal force, which holds this revolving body _to_ the +center, is the only force which is being exerted upon it. + +Where, then, is the centrifugal force? Why, the fact is, there is not +any such thing. In the dynamical sense of the term "force," the sense in +which this term is always understood in ordinary speech, as something +tending to produce motion, and the direction of which determines the +direction in which motion of a body must take place, there is, I repeat, +no such thing as centrifugal force. + +There is, however, another sense in which the term "force" is employed, +which, in distinction from the above, is termed a statical sense. This +"statical force" is the force by the exertion of which a body keeps +still. It is the force of inertia--the resistance which all matter +opposes to a dynamical force exerted to put it in motion. This is the +sense in which the term "force" is employed in the expression +"centrifugal force." Is that all? you ask. Yes; that is all. + +I must explain to you how it is that a revolving body exerts this +resistance to being put in motion, when all the while it _is_ in motion, +with, according to our above supposition, a uniform velocity. The first +law of motion, so far as we now have occasion to employ it, is that a +body, when put in motion, moves in a straight line. This a moving body +always does, unless it is acted on by some force, other than its +impelling force, which deflects it, or turns it aside, from its direct +line of motion. A familiar example of this deflecting force is afforded +by the force of gravity, as it acts on a projectile. The projectile, +discharged at any angle of elevation, would move on in a straight line +forever, but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made to +fall, by the attraction of the earth; and so instead of a straight line +it describes a curve, known as the trajectory. + +Now a revolving body, also, has the same tendency to move in a straight +line. It would do so, if it were not continually deflected from this +line. Another force is constantly exerted upon it, compelling it, at +every successive point of its path, to leave the direct line of motion, +and move on a line which is everywhere equally distant from the center +to which it is held. If at any point the revolving body could get free, +and sometimes it does get free, it would move straight on, in a line +tangent to the circle at the point of its liberation. But if it cannot +get free, it is compelled to leave each new tangential direction, as +soon as it has taken it. + +This is illustrated in the above figure. The body, A, is supposed to be +revolving in the direction indicated by the arrow, in the circle, A B F +G, around the center, O, to which it is held by the cord, O A. At the +point, A, it is moving in the tangential direction, A D. It would +continue to move in this direction, did not the cord, O A, compel it to +move in the arc, A C. Should this cord break at the point, A, the body +would move; straight on toward D, with whatever velocity it had. + +You perceive now what centrifugal force is. This body is moving in the +direction, A D. The centripetal force, exerted through the cord, O A, +pulls it aside from this direction of motion. The body resists this +deflection, and this resistance is its centrifugal force. + +[Illustration: Fig. 1] + +Centrifugal force is, then, properly defined to be the disposition of a +revolving body to move in a straight line, and the resistance which such +a body opposes to being drawn aside from a straight line of motion. The +force which draws the revolving body continually to the center, or the +deflecting force, is called the centripetal force, and, aside from the +impelling and retarding forces which act in the direction of its motion, +the centripetal force is, dynamically speaking, the only force which is +exerted on the body. + +It is true, the resistance of the body furnishes the measure of the +centripetal force. That is, the centripetal force must be exerted in a +degree sufficient to overcome this resistance, if the body is to move in +the circular path. In this respect, however, this case does not differ +from every other case of the exertion of force. Force is always exerted +to overcome resistance: otherwise it could not be exerted. And the +resistance always furnishes the exact measure of the force. I wish to +make it entirely clear, that in the dynamical sense of the term "force," +there is no such thing as centrifugal force. The dynamical force, that +which produces motion, is the centripetal force, drawing the body +continually from the tangential direction, toward the center; and what +is termed centrifugal force is merely the resistance which the body +opposes to this deflection, _precisely like any other resistance to a +force_. + +The centripetal force is exerted on the radial line, as on the line, A +O, Fig. 1, at right angles with the direction in which the body is +moving; and draws it directly toward the center. It is, therefore, +necessary that the resistance to this force shall also be exerted on the +same line, in the opposite direction, or directly from the center. But +this resistance has not the least power or tendency to produce motion in +the direction in which it is exerted, any more than any other resistance +has. + +We have been supposing a body to be firmly held to the center, so as to +be compelled to revolve about it in a fixed path. But the bond which +holds it to the center may be elastic, and in that case, if the +centrifugal force is sufficient, the body will be drawn from the center, +stretching the elastic bond. It may be asked if this does not show +centrifugal force to be a force tending to produce motion from the +center. This question is answered by describing the action which really +takes place. The revolving body is now imperfectly deflected. The bond +is not strong enough to compel it to leave its direct line of motion, +and so it advances a certain distance along this tangential line. This +advance brings the body into a larger circle, and by this enlargement of +the circle, assuming the rate of revolution to be maintained, its +centrifugal force is proportionately increased. The deflecting power +exerted by the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct path; +and when the limit of its elasticity is reached, the deflecting bond +will be broken. If, however, the strength of the deflecting bond is +increased by its elongation in a more rapid ratio than the centrifugal +force is increased by the enlargement of the circle, then a point will +be reached in which the centripetal force will be sufficient to compel +the body to move again in the circular path. + +Sometimes the centripetal force is weak, and opportunity is afforded to +observe this action, and see its character exhibited. A common example +of weak centripetal force is the adhesion of water to the face of a +revolving grindstone. Here we see the deflecting force to become +insufficient to compel the drops of water longer to leave their direct +paths, and so these do not longer leave their direct paths, but move on +in those paths, with the velocity they have at the instant of leaving +the stone, flying off on tangential lines. + +If, however, a fluid be poured on the side of the revolving wheel near +the axis, it will move out to the rim on radial lines, as may be +observed on car wheels universally. The radial lines of black oil on +these wheels look very much as if centrifugal force actually did produce +motion, or had at least a very decided tendency to produce motion, in +the radial direction. This interesting action calls for explanation. In +this action the oil moves outward gradually, or by inconceivably minute +steps. Its adhesion being overcome in the least possible degree, it +moves in the same degree tangentially. In so doing it comes in contact +with a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it had +overcome the adhesion. Motion in the radial direction is the result of +these two actions, namely, leaving the first point of contact +tangentially and receiving an acceleration of its motion, so that this +shall be equal to that of the second point of contact. When we think +about the matter a little closely, we see that at the rim of the wheel +the oil has perhaps ten times the velocity of revolution which it had on +leaving the journal, and that the mystery to be explained really is, How +did it get that velocity, moving out on a radial line? Why was it not +left behind at the very first? Solely by reason of its forward +tangential motion. That is the answer. + +When writers who understand the subject talk about the centripetal and +centrifugal forces being different names for the same force, and about +equal action and reaction, and employ other confusing expressions, just +remember that all they really mean is to express the universal relation +between force and resistance. The expression "centrifugal force" is +itself so misleading, that it becomes especially important that the real +nature of this so-called force, or the sense in which the term "force" +is used in this expression, should be fully explained.[1] This force is +now seen to be merely the tendency of a revolving body to move in a +straight line, and the resistance which it opposes to being drawn aside +from that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see. + +[Footnote 1: I was led to study this subject in looking to see what had +become of my first permanent investment, a small venture, made about +thirty-five years ago, in the "Sawyer and Gwynne static pressure +engine." This was the high-sounding name of the Keely motor of that day, +an imposition made possible by the confused ideas prevalent on this very +subject of centrifugal force.] + +FIRST.--I have called your attention to the fact that the direction in +which the revolving body is deflected from the tangential line of motion +is toward the center, on the radial line, which forms a right angle with +the tangent on which the body is moving. The first question that +presents itself is this: What is the measure or amount of this +deflection? The answer is, this measure or amount is the versed sine of +the angle through which the body moves. + +Now, I suspect that some of you--some of those whom I am directly +addressing--may not know what the versed sine of an angle is; so I must +tell you. We will refer again to Fig. 1. In this figure, O A is one +radius of the circle in which the body A is revolving. O C is another +radius of this circle. These two radii include between them the angle A +O C. This angle is subtended by the arc A C. If from the point O we let +fall the line C E perpendicular to the radius O A, this line will divide +the radius O A into two parts, O E and E A. Now we have the three +interior lines, or the three lines within the circle, which are +fundamental in trigonometry. C E is the sine, O E is the cosine, and E A +is the versed sine of the angle A O C. Respecting these three lines +there are many things to be observed. I will call your attention to the +following only: + +_First_.--Their length is always less than the radius. The radius is +expressed by 1, or unity. So, these lines being less than unity, their +length is always expressed by decimals, which mean equal to such a +proportion of the radius. + +_Second_.--The cosine and the versed sine are together equal to the +radius, so that the versed sine is always 1, less the cosine. + +_Third_.--If I diminish the angle A O C, by moving the radius O C toward +O A, the sine C E diminishes rapidly, and the versed sine E A also +diminishes, but more slowly, while the cosine O E increases. This you +will see represented in the smaller angles shown in Fig. 2. If, finally, +I make O C to coincide with O A, the angle is obliterated, the sine and +the versed sine have both disappeared, and the cosine has become the +radius. + +_Fourth_.--If, on the contrary, I enlarge the angle A O C by moving the +radius O C toward O B, then the sine and the versed sine both increase, +and the cosine diminishes; and if, finally, I make O C coincide with O +B, then the cosine has disappeared, the sine has become the radius O B, +and the versed sine has become the radius O A, thus forming the two +sides inclosing the right angle A O B. The study of this explanation +will make you familiar with these important lines. The sine and the +cosine I shall have occasion to employ in the latter part of my lecture. +Now you know what the versed sine of an angle is, and are able to +observe in Fig. 1 that the versed sine A E, of the angle A O C, +represents in a general way the distance that the body A will be +deflected from the tangent A D toward the center O while describing the +arc A C. + +The same law of deflection is shown, in smaller angles, in Fig. 2. In +this figure, also, you observe in each of the angles A O B and A O C +that the deflection, from the tangential direction toward the center, of +a body moving in the arc A C is represented by the versed sine of the +angle. The tangent to the arc at A, from which this deflection is +measured, is omitted in this figure to avoid confusion. It is shown +sufficiently in Fig. 1. The angles in Fig. 2 are still pretty large +angles, being 12° and 24° respectively. These large angles are used for +convenience of illustration; but it should be explained that this law +does not really hold in them, as is evident, because the arc is longer +than the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent and +arc coincide, and approximately so for exceedingly small angles. + +[Illustration: Fig. 2] + +In reality, however, we have only to do with the case in which the arc +and the tangent do coincide, and in which the law that the deflection is +_equal to_ the versed sine of the angle is absolutely true. Here, in +observing this most familiar thing, we are, at a single step, taken to +that which is utterly beyond our comprehension. The angles we have to +consider disappear, not only from our sight, but even from our +conception. As in every other case when we push a physical investigation +to its limit, so here also, we find our power of thought transcended, +and ourselves in the presence of the infinite. + +We can discuss very small angles. We talk familiarly about the angle +which is subtended by 1" of arc. On Fig. 2, a short line is drawn near +to the radius O A'. The distance between O A' and this short line is 1° +of the arc A' B'. If we divide this distance by 3,600, we get 1" of arc. +The upper line of the Table of versed sines given below is the versed +sine of 1" of arc. It takes 1,296,000 of these angles to fill a circular +space. These are a great many angles, but they do not make a circle. +They make a polygon. If the radius of the circumscribed circle of this +polygon is 1,296,000 feet, which is nearly 213 geographical miles, each +one of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon would be +one-sixtieth of a geographical mile, or 101.46 feet. On the orbit of the +moon, at its mean distance from the earth, each of these straight sides +would be about 6,000 feet long. + +The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never can +reach the circle. When you swing a sling around your head, and feel the +uniform stress exerted on your hand through the cord, you are made aware +of an action which is entirely beyond the grasp of our minds and the +reach of our analysis. + +So always in practical operation that law is absolutely true which we +observe to be approximated to more and more nearly as we consider +smaller and smaller angles, that the versed sine of the angle is the +measure of its deflection from the straight line of motion, or the +measure of its fall toward the center, which takes place at every point +in the motion of a revolving body. + +Then, assuming the absolute truth of this law of deflection, we find +ourselves able to explain all the phenomena of centrifugal force, and to +compute its amount correctly in all cases. + +We have now advanced two steps. We have learned _the direction_ and _the +measure_ of the deflection, which a revolving body continually suffers, +and its resistance to which is termed centrifugal force. The direction +is toward the center, and the measure is the versed sine of the angle. + +SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that the +amount of centrifugal force exerted by a revolving body varies in four +ways. + +_First_.--Directly as the weight of the body. + +_Second_.--In a given circle of revolution, as the square of the speed +or of the number of revolutions per minute; which two expressions in +this case mean the same thing. + +_Third_.--With a given number of revolutions per minute, or a given +angular velocity[1] _directly_ as the radius of the circle; and + +_Fourth_.--With a given actual velocity, or speed in feet per minute, +_inversely_ as the radius of the circle. + +[Footnote 1: A revolving body is said to have the same angular velocity, +when it sweeps through equal angles in equal times. Its actual velocity +varies directly as the radius of the circle in which it is revolving.] + +Of course there is a reason for these laws. You are not to learn them by +rote, or to accept them on any authority. You are taught not to accept +any rule or formula on authority, but to demand the reason for it--to +give yourselves no rest until you know the why and wherefore, and +comprehend these fully. This is education, not cramming the mind with +mere facts and rules to be memorized, but drawing out the mental powers +into activity, strengthening them by use and exercise, and forming the +habit, and at the same time developing the power, of penetrating to the +reason of things. + +In this way only, you will be able to meet the requirement of a great +educator, who said: "I do not care to be told what a young man knows, +but what he can _do_." I wish here to add my grain to the weight of +instruction which you receive, line upon line, precept on precept, on +this subject. + +The reason for these laws of centrifugal force is an extremely simple +one. The first law, that this force varies directly as the weight of the +body, is of course obvious. We need not refer to this law any further. +The second, third, and fourth laws merely express the relative rates at +which a revolving body is deflected from the tangential direction of +motion, in each of the three cases described, and which cases embrace +all possible conditions. + +These three rates of deflection are exhibited in Fig. 2. An examination +of this figure will give you a clear understanding of them. Let us first +suppose a body to be revolving about the point, O, as a center, in a +circle of which A B C is an arc, and with a velocity which will carry it +from A to B in one second of time. Then in this time the body is +deflected from the tangential direction a distance equal to A D, the +versed sine of the angle A O B. Now let us suppose the velocity of this +body to be doubled in the same circle. In one second of time it moves +from A to C, and is deflected from the tangential direction of motion a +distance equal to A E, the versed sine of the angle, A O C. But A E is +four times A D. Here we see in a given circle of revolution the +deflection varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded. + +The following table will show, by comparison of the versed sines of very +small angles, the deflection in a given circle varying as the square of +the speed, when we penetrate to them, so nearly that the error is not +disclosed at the fifteenth place of decimals. + + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 + +You observe the deflection for 10" of arc is 100 times as great, and for +100" of arc is 10,000 times as great as it is for 1" of arc. So far as +is shown by the 15th place of decimals, the versed sine varies as the +square of the angle; or, in a given circle, the deflection, and so the +centrifugal force, of a revolving body varies as the square of the +speed. + +The reason for the third law is equally apparent on inspection of Fig. +2. It is obvious, that in the case of bodies making the same number of +revolutions in different circles, the deflection must vary directly as +the diameter of the circle, because for any given angle the versed sine +varies directly as the radius. Thus radius O A' is twice radius O A, and +so the versed sine of the arc A' B' is twice the versed sine of the arc +A B. Here, while the angular velocity is the same, the actual velocity +is doubled by increase in the diameter of the circle, and so the +deflection is doubled. This exhibits the general law, that with a given +angular velocity the centrifugal force varies directly as the radius or +diameter of the circle. + +We come now to the reason for the fourth law, that, with a given actual +velocity, the centrifugal force varies _inversely_ as the diameter of +the circle. If any of you ever revolved a weight at the end of a cord +with some velocity, and let the cord wind up, suppose around your hand, +without doing anything to accelerate the motion, then, while the circle +of revolution was growing smaller, the actual velocity continuing nearly +uniform, you have felt the continually increasing stress, and have +observed the increasing angular velocity, the two obviously increasing +in the same ratio. That is the operation or action which the fourth law +of centrifugal force expresses. An examination of this same figure (Fig. +2) will show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. If we +take the velocity A' B', double the velocity A B, and transfer it to the +smaller circle, we have the velocity A C. But the deflection has been +increasing as we have reduced the circle, and now with one half the +radius it is twice as great. It has increased in the same ratio in which +the angular velocity has increased. Thus we see the simple and necessary +nature of these laws. They merely express the different rates of +deflection of a revolving body in these different cases. + +THIRD.--We have a coefficient of centrifugal force, by which we are +enabled to compute the amount of this resistance of a revolving body to +deflection from a direct line of motion in all cases. This is that +coefficient. The centrifugal force of a body making _one_ revolution per +minute, in a circle of _one_ foot radius, is 0.000341 of the weight of +the body. + +According to the above laws, we have only to multiply this coefficient +by the square of the number of revolutions made by the body per minute, +and this product by the radius of the circle in feet, or in decimals of +a foot, and we have the centrifugal force, in terms of the weight of the +body. Multiplying this by the weight of the body in pounds, we have the +centrifugal force in pounds. + +Of course you want to know how this coefficient has been found out, and +how you can be sure it is correct. I will tell you a very simple way. +There are also mathematical methods of ascertaining this coefficient, +which your professors, if you ask them, will let you dig out for +yourselves. The way I am going to tell you I found out for myself, and +that, I assure you, is the only way to learn anything, so that it will +stick; and the more trouble the search gives you, the darker the way +seems, and the greater the degree of perseverance that is demanded, the +more you will appreciate the truth when you have found it, and the more +complete and permanent your possession of it will be. + +The explanation of this method may be a little more abstruse than the +explanations already given, but it is very simple and elegant when you +see it, and I fancy I can make it quite clear. I shall have to preface +it by the explanation of two simple laws. The first of these is, that a +body acted on by a constant force, so as to have its motion uniformly +accelerated, suppose in a straight line, moves through distances which +increase as the square of the time that the accelerating force continues +to be exerted. + +The necessary nature of this law, or rather the action of which this law +is the expression, is shown in Fig. 3. + +[Illustration: Fig. 3] + +Let the distances A B, B C, C D, and D E in this figure represent four +successive seconds of time. They may just as well be conceived to +represent any other equal units, however small. Seconds are taken only +for convenience. At the commencement of the first second, let a body +start from a state of rest at A, under the action of a constant force, +sufficient to move it in one second through a distance of one foot. This +distance also is taken only for convenience. At the end of this second, +the body will have acquired a velocity of two feet per second. This is +obvious because, in order to move through one foot in this second, the +body must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. Its +motion increased uniformly. Therefore, at the termination of the second +its velocity must have reached two feet per second. Let the triangle A B +F represent this accelerated motion, and the distance, of one foot, +moved through during the first second, and let the line B F represent +the velocity of two feet per second, acquired by the body at the end of +it. Now let us imagine the action of the accelerating force suddenly to +cease, and the body to move on merely with the velocity it has acquired. +During the next second it will move through two feet, as represented by +the square B F C I. But in fact, the action of the accelerating force +does not cease. This force continues to be exerted, and produces on the +body during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity accelerated +two additional feet per second, as represented by the line I G. So in +two seconds the body has moved through four feet. We may follow the +operation of this law as far as we choose. The figure shows it during +four seconds, or any other unit, of time, and also for any unit of +distance. Thus: + + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 + +So it is obvious that the distance moved through by a body whose motion +is uniformly accelerated increases as the square of the time. + +But, you are asking, what has all this to do with a revolving body? As +soon as your minds can be started from a state of rest, you will +perceive that it has everything to do with a revolving body. The +centripetal force, which acts upon a revolving body to draw it to the +center, is a constant force, and under it the revolving body must move +or be deflected through distances which increase as the squares of the +times, just as any body must do when acted on by a constant force. To +prove that a revolving body obeys this law, I have only to draw your +attention to Fig. 2. Let the equal arcs, A B and B C, in this figure +represent now equal times, as they will do in case of a body revolving +in this circle with a uniform velocity. The versed sines of the angles, +A O B and A O C, show that in the time, A C, the revolving body was +deflected four times as far from the tangent to the circle at A as it +was in the time, A B. So the deflection increased as the square of the +time. If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute angles, +absolutely so far as appears up to the fifteenth place of decimals, as +the square of the time. + +The standard from which all computations are made of the distances +passed through in given times by bodies whose motion is uniformly +accelerated, and from which the velocity acquired is computed when the +accelerating force is known, and the force is found when the velocity +acquired or the rate of acceleration is known, is the velocity of a body +falling to the earth. It has been established by experiment, that in +this latitude near the level of the sea, a falling body in one second +falls through a distance of 16.083 feet, and acquires a velocity of +32.166 feet per second; or, rather, that it would do so if it did not +meet the resistance of the atmosphere. In the case of a falling body, +its weight furnishes, first, the inertia, or the resistance to motion, +that has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the earth, or +the force exerted to overcome its resistance. Here, as in all possible +cases, the force and the resistance are identical with each other. The +above is, therefore, found in this way to be the rate at which the +motion of any body will be accelerated when it is acted on by a constant +force equal to its weight, and encounters no resistance. + +It follows that a revolving body, when moving uniformly in any circle at +a speed at which its deflection from a straight line of motion is such +that in one second this would amount to 16.083 feet, requires the +exertion of a centripetal force equal to its weight to produce such +deflection. The deflection varying as the square of the time, in 0.01 of +a second this deflection will be through a distance of 0.0016083 of a +foot. + +Now, at what speed must a body revolve, in a circle of one foot radius, +in order that in 0.01 of one second of time its deflection from a +tangential direction shall be 0.0016083 of a foot? This decimal is the +versed sine of the arc of 3°15', or of 3.25°. This angle is so small +that the departure from the law that the deflection is equal to the +versed sine of the angle is too slight to appear in our computation. +Therefore, the arc of 3.25° is the arc of a circle of one foot radius +through which a body must revolve in 0.01 of a second of time, in order +that the centripetal force, and so the centrifugal force, shall be equal +to its weight. At this rate of revolution, in one second the body will +revolve through 325°, which is at the rate of 54.166 revolutions per +minute. + +Now there remains only one question more to be answered. If at 54.166 +revolutions per minute the centrifugal force of a body is equal to its +weight, what will its centrifugal force be at one revolution per minute +in the same circle? + +To answer this question we have to employ the other extremely simple +law, which I said I must explain to you. It is this: The acceleration +and the force vary in a constant ratio with each other. Thus, let force +1 produce acceleration 1, then force 1 applied again will produce +acceleration 1 again, or, in other words, force 2 will produce +acceleration 2, and so on. This being so, and the amount of the +deflection varying as the squares of the speeds in the two cases, the +centrifugal force of a body making one revolution per minute in a circle +of + + 1² + one foot radius will be ---------- = 0.000341 + 54.166² + +--the coefficient of centrifugal force. + +There is another mode of making this computation, which is rather neater +and more expeditious than the above. A body making one revolution per +minute in a circle of one foot radius will in one second revolve through +an arc of 6°. The versed sine of this arc of 6° is 0.0054781046 of a +foot. This is, therefore, the distance through which a body revolving at +this rate will be deflected in one second. If it were acted on by a +force equal to its weight, it would be deflected through the distance of +16.083 feet in the same time. What is the deflecting force actually +exerted upon it? Of + + 0.0054781046 +course, it is ------------. + 16.083 + +This division gives 0.000341 of its weight as such deflecting force, the +same as before. + +In taking the versed sine of 6°, a minute error is involved, though not +one large enough to change the last figure in the above quotient. The +law of uniform acceleration does not quite hold when we come to an angle +so large as 6°. If closer accuracy is demanded, we can attain it, by +taking the versed sine for 1°, and multiplying this by 6². This gives as +a product 0.0054829728, which is a little larger than the versed sine of +6°. + +I hope I have now kept my promise, and made it clear how the coefficient +of centrifugal force may be found in this simple way. + +We have now learned several things about centrifugal force. Let me +recapitulate. We have learned: + +1st. The real nature of centrifugal force. That in the dynamical sense +of the term force, this is not a force at all: that it is not capable of +producing motion, that the force which is really exerted on a revolving +body is the centripetal force, and what we are taught to call +centrifugal force is nothing but the resistance which a revolving body +opposes to this force, precisely like any other resistance. + +2d. The direction of the deflection, to which the centrifugal force is +the resistance, which is straight to the center. + +3d. The measure of this deflection; the versed sine of the angle. + +4th. The reason of the laws of centrifugal force; that these laws merely +express the relative amount of the deflection, and so the amount of the +force required to produce the deflection, and of the resistance of the +revolving body to it, in all different cases. + +5th. That the deflection of a revolving body presents a case analogous +to that of uniformly accelerated motion, under the action of a constant +force, similar to that which is presented by falling bodies;[1] and +finally, + +6th. How to find the coefficient, by which the amount of centrifugal +force exerted in any case may be computed. + +[Footnote 1: A body revolving with a uniform velocity in a horizontal +plane would present the only case of uniformly accelerated motion that +is possible to be realized under actual conditions.] + +I now pass to some other features. + +_First_.--You will observe that, relatively to the center, a revolving +body, at any point in its revolution, is at rest. That is, it has no +motion, either from or toward the center, except that which is produced +by the action of the centripetal force. It has, therefore, this identity +also with a falling body, that it starts from a state of rest. This +brings us to a far more comprehensive definition of centrifugal force. +This is the resistance which a body opposes to being put in motion, at +any velocity acquired in any time, from a state of rest. Thus +centrifugal force reveals to us the measure of the inertia of matter. +This inertia may be demonstrated and exhibited by means of apparatus +constructed on this principle quite as accurately as it can be in any +other way. + +_Second_.--You will also observe the fact, that motion must be imparted +to a body gradually. As distance, _through_ which force can act, is +necessary to the impartation of velocity, so also time, _during_ which +force can act, is necessary to the same result. We do not know how +motion from a state of rest begins, any more than we know how a polygon +becomes a circle. But we do know that infinite force cannot impart +absolutely instantaneous motion to even the smallest body, or to a body +capable of opposing the least resistance. Time being an essential +element or factor in the impartation of velocity, if this factor be +omitted, the least resistance becomes infinite. + +We have a practical illustration of this truth in the explosion of +nitro-glycerine. If a small portion of this compound be exploded on the +surface of a granite bowlder, in the open air, the bowlder will be rent +into fragments. The explanation of this phenomenon common among the +laborers who are the most numerous witnesses of it, which you have +doubtless often heard, and which is accepted by ignorant minds without +further thought, is that the action of nitro-glycerine is downward. We +know that such an idea is absurd. + +The explosive force must be exerted in all directions equally. The real +explanation is, that the explosive action of nitro-glycerine is so +nearly instantaneous, that the resistance of the atmosphere is very +nearly equal to that of the rock; at any rate, is sufficient to cause +the rock to be broken up. The rock yields to the force very nearly as +readily as the atmosphere does. + +_Third_. An interesting solution is presented here of what is to many an +astronomical puzzle. When I was younger than I am now, I was greatly +troubled to understand how it could be that if the moon was always +falling to the earth, as the astronomers assured us it was, it should +never reach it, nor have its falling velocity accelerated. In popular +treatises on astronomy, such for example as that of Professor Newcomb, +this is explained by a diagram in which the tangential line is carried +out as in Fig. 1, and by showing that in falling from the point A to the +earth as a center, through distances increasing as the square of the +time, the moon, having the tangential velocity that it has, could never +get nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this long +tangential line has nothing to do with the motion of the moon, and while +we are compelled to assent to the demonstration, we want something +better. To my mind the better and more satisfactory explanation is found +in the fact that the moon is forever commencing to fall, and is +continually beginning to fall in a new direction. A revolving body, as +we have seen, never gets past that point, which is entirely beyond our +sight and our comprehension, of beginning to fall, before the direction +of its fall is changed. So, under the attraction of the earth, the moon +is forever leaving a new tangential direction of motion at the same +rate, without acceleration. + +(_To be continued_.) + + * * * * * + + + + +COMPRESSED AIR POWER SCHEMES. + +By J. STURGEON, Engineer of the Birmingham Compressed Air Power Company. + + +In the article on "Gas, Air, and Water Power" in the _Journal_ for Dec. +8 last, you state that you await with some curiosity my reply to certain +points in reference to the compressed air power schemes alluded to in +that article. I now, therefore, take the liberty of submitting to you +the arguments on my side of the question (which are substantially the +same as those I am submitting to Mr. Hewson, the Borough Engineer of +Leeds). The details and estimates for the Leeds scheme are not yet in a +forward enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system in +other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters of +detail. We have, however, recently succeeded in obtaining a suitable +place, and making arrangements for railway siding, water supply, etc.; +and we hope to be in a position to start early in the present year. + +I inclose (1) a tabulated summary of the estimates for Birmingham +divided into stages of 3,000 gross indicated horse power at a time; (2) +a statement showing the cost to consumers in terms of indicated horse +power and in different modes, more or less economical, of applying the +air power in the consumers' engines; (3) a tracing showing the method of +laying the mains; (4) a tracing showing the method of collecting the +meter records at the central station, by means of electric apparatus, +and ascertaining the exact amount of leakage. A short description of the +two latter would be as well. + +TABLE I.--_Showing the Progressive Development of the Compressed Air +System in stages of 3000 Indicated Horse Power (gross) at a Time, and +the Profits at each Stage_ + +_____________________________________________________________________________ + +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- + +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- + +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| £12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | £25,595 | £25,595 | £25,595 | £25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | £82,455 | £124,714 | £167,094 | £209,455 | £251,795 | +----------------------------------------------------------------------------- + +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| £6,405 | £7,855 | £9,305 | £10,955 | £12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | £12,080 | £18,508 | £24,944 | £31,589 | £38,096 | +----------------------------------------------------------------------------- + +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- + +TABLE II.--_Cost of Air Power in Terms of Indicated Horse Power_. + +Abbreviated column headings: + +Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per +Hour. + +Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet. + +Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per +Cent. + +Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet. + +Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per +Cent. + +Abbreviated row headings: + +CASE 1.--Where air at 45 lbs. pressure is re-heated to 320° Fahr., and +expanded to atmospheric pressure. + +CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to +212° Fahr., and expanded to atmospheric pressure. + +CASE 3.--Where air is used expansively without re-heating, whereby +intensely cold air is exhausted, and may be used for ice making, &c. + +CASE 4.--Where air is heated to 212° Fahr., and the terminal pressure is +11.3 lbs. above that of the atmosphere + +CASE 5.--Where the air is used without heating, and cut off at one-third +of the stroke, as in ordinary slide-valve engines + +CASE 6.--Where the air is used without re-heating and without expansion. + + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | £ s. d. | £ s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 0½| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 5½ | 9 10 5½| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 5½ | 9 1 10½| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ + +The great thing to guard against is leakage. If the pipes were simply +buried in the ground, it would be almost impossible to trace leakage, or +even to know of its existence. The income of the company might be +wasting away, and the loss never suspected until the quarterly returns +from the meters were obtained from the inspectors. Only then would it be +discovered that there must be a great leak (or it might be several +leaks) somewhere. But how would it be possible to trace them among 20 or +30 miles of buried pipes? We cannot break up the public streets. The +very existence of the concern depends upon (1) the _daily_ checking of +the meter returns, and comparison with the output from the air +compressors, so as to ascertain the amount of leakage; (2) facility for +tracing the locality of a leak; and (3) easy access to the mains with +the minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the pipes +are laid in concrete troughs, near the surface of the road, with +removable concrete covers strong enough to stand any overhead traffic. +At intervals there are junctions for service connections, with street +boxes and covers serving as inspection chambers. These chambers are also +provided over the ball-valves, which serve as stop-valves in case of +necessity, and are so arranged that in case of a serious breach in the +portion of main between any two of them, the rush of air to the breach +will blow them up to the corresponding seats and block off the broken +portion of main. The air space around the pipe in the concrete trough +will convey for a long distance the whistling noise of a leak; and the +inspectors, by listening at the inspection openings, will thus be +enabled to rapidly trace their way almost to the exact spot where there +is an escape. They have then only to remove the top surface of road +metal and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring from +the nearest street opening, the inspectors would know where to break +open the road to arrive at the probable locality of the leak. A very +slight leak can be heard a long way off by its peculiar whistling sound. + +[Illustration: COMPRESSED AIR POWER] + +The next point is to obtain a daily report of the condition of the mains +and the amount of leakage. It would be impracticable to employ an army +of meter inspectors to take the records daily from all the meters in the +district. We therefore adopt the method of electric signaling shown in +the second drawing. In the engineer's office, at the central station, is +fixed the dial shown in Fig. 1. Each consumer's meter is fitted with the +contact-making apparatus shown in Pig. 4, and in an enlarged form in +Figs. 5 and 6, by which a current is sent round the electro-magnet, D +(Fig. 1), attracting the armature, and drawing the disk forward +sufficiently for the roller at I to pass over the center of one of the +pins, and so drop in between that and the next pin, thus completing the +motion, and holding the disk steadily opposite the figure. This action +takes place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose one +meter should be moving very slowly, and so retaining contact for some +time, while other meters were working rapidly; the armature at D would +then be held up to the magnet by the prolonged contact maintained by the +slow moving meter, and so prevent the quick working meters from +actuating it; and they would therefore pass the contact points without +recording. A meter might also stop dead at the point of contact on +shutting off the air, and so hold up the armature; thus preventing +others from acting. To obviate this, we apply the disengaging apparatus +shown at L (Fig. 4). The contact maker works on the center, m, having an +armature on its opposite end. On contact being made, at the same time +that the magnet, D, is operated, the one at L is also operated, +attracting the armature, and throwing over the end of the contact maker, +l¹, on to the non-conducting side of the pin on the disk. Thus the whole +movement is rendered practically instantaneous, and the magnet at D is +set at liberty for the next operation. A resistance can be interposed at +L, if necessary, to regulate the period of the operation. The whole of +the meters work the common dial shown in Fig. 1, on which the gross +results only are recorded; and this is all we want to know in this way. +The action is so rapid, owing to the use of the magnetic disengaging +gear, that the chances of two or more meters making contact at the same +moment are rendered extremely small. Should such a thing happen, it +would not matter, as it is only approximate results that we require in +this case; and the error, if any, would add to the apparent amount of +leakage, and so be on the right side. Of course, the record of each +consumer's meter would be taken by the inspector at the end of every +quarter, in order to make out the bill; and the totals thus obtained +would be checked by the gross results indicated by the main dial. In +this way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected to an +extremely accurate measurement. At the end of the working day, the +engineer has merely to take down from the dial in his office the total +record of air measured to the consumers, also the output of air from the +compressors, which he ascertains by means of a continuous counter on the +engines, and the difference between the two will represent the loss. If +the loss is trifling, he will pass it over; if serious, he will send out +his inspectors to trace it. Thus there could be no long continued +leakage, misuse, or robbery of the air, without the company becoming +aware of the fact, and so being enabled to take measures to stop or +prevent it. The foregoing are absolutely essential adjuncts to any +scheme of public motive power supply by compressed air, without which we +should be working in the dark, and could never be sure whether the +company were losing or making money. With them, we know where we are and +what we are doing. + +Referring to the estimates given in Table I., I may explain that the +item of repairs and renewals covers 10 per cent. on boilers and gas +producers, 5 per cent. on engines, 5 per cent. on buildings, and 5 per +cent. on mains. Considering that the estimates include ample fitting +shops, with the best and most suitable tools, and that the wages list +includes a staff of men whose chief work would be to attend to repairs, +etc., I think the above allowances ample. Each item also includes 5 per +cent. for contingencies. + +I have commenced by giving all the preceding detail, in order to show +the groundwork on which I base the estimate of the cost of compressed +air power to consumers, in terms of indicated horse power per annum, as +given in Table II. I may say that, in estimating the engine power and +coal consumption, I have not, as in the original report, made purely +theoretical calculations, but have taken diagrams from engines in actual +use (although of somewhat smaller size than those intended to be +employed), and have worked out the results therefrom. It will, I hope, +be seen that, with all the safeguards we have provided, we may fairly +reckon upon having for sale the stated quantity of air produced by means +of the plant, as estimated, and at the specified annual cost; and that +therefore the statement of cost per indicated horse power per annum may +be fairly relied upon. Thus the cost of compressed air to the consumer, +based upon an _average_ charge of 5d. per 1,000 cubic feet, will vary +from £6 14s. per indicated horse power per annum to £18 13s. 3d., +according to circumstances and mode of application. + +A compressed air motor is an exceedingly simple machine--much simpler +than an ordinary steam engine. But the air may also be used in an +ordinary steam engine; and in this case it can be much simplified in +many details. Very little packing is needed, as there is no nuisance +from gland leakage; the friction is therefore very slight. Pistons and +glands are packed with soapstone, or other self-lubricating packing; and +no oil is required except for bearings, etc. The company will undertake +the periodical inspection and overhauling of engines supplied with their +power, all which is included in the estimates. The total cost to +consumers, with air at an average of 5d. per 1,000 cubic feet, may +therefore be fairly taken as follows: + + Min. Max. + Cost of air used £6 14 0½ £18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 12½ per cent. on + £10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + £8 19 0½ £20 18 3 + +The maximum case would apply only to direct acting engines, such as +Tangye pumps, air power hammers, etc., where the air is full on till the +end of the stroke, and where there is no expansion. The minimum given is +at the average rate of 5d. per 1,000 cubic feet; but as there will be +rates below this, according to a sliding scale, we may fairly take it +that the lowest charge will fall considerably below £6 per indicated +horse power per annum.--_Journal of Gas Lighting_. + + * * * * * + + + + +THE BERTHON COLLAPSIBLE CANOE. + + +An endeavor has often been made to construct a canoe that a person can +easily carry overland and put into the water without aid, and convert +into a sailboat. The system that we now call attention to is very well +contrived, very light, easily taken apart, and for some years past has +met with much favor. + +[Illustration: FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.] + +Mr. Berthon's canoes are made of impervious oil-skin. Form is given them +by two stiff wooden gunwales which are held in position by struts that +can be easily put in and taken out. The model shown in the figure is +covered with oiled canvas, and is provided with a double paddle and a +small sail. Fig. 2 represents it collapsed and being carried overland. + +[Illustration: FIG. 2.--THE SAME BEING CARRIED OVERLAND.] + +Mr. Berthon is manufacturing a still simpler style, which is provided +with two oars, as in an ordinary canoe. This model, which is much used +in England by fishermen and hunters, has for several years past been +employed in the French navy, in connection with movable defenses. At +present, every torpedo boat carries one or two of these canoes, each +composed of two independent halves that may be put into the water +separately or be joined together by an iron rod. + +These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure without +danger.[1]--_La Nature_. + +[Footnote 1: For detailed description see SUPPLEMENT, No. 84.] + + * * * * * + + + + +THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN STEAM +RAILROAD. + + +There was great excitement in Nürnberg on the 7th of December, 1835, on +which day the first German railroad was opened. The great square on +which the buildings of the Nürnberg and Furth "Ludwig's Road" stood, the +neighboring streets, and, in fact, the whole road between the two +cities, was filled with a crowd of people who flocked from far and near +to see the wonderful spectacle. For the first time, a railroad train +filled with passengers was to be drawn from Nürnberg to Furth by the +invisible power of the steam horse. At eight o'clock in the morning, the +civil and military authorities, etc., who took part in the celebration +were assembled on the square, and the gayly decorated train started off +to an accompaniment of music, cannonading, cheering, etc. Everything +passed off without an accident; the work was a success. The engraving in +the lower right-hand corner represents the engine and cars of this road. + +It will be plainly seen that such a revolution could not be accomplished +easily, and that much sacrifice and energy were required of the leaders +in the enterprise, prominent among whom was the merchant Johannes +Scharrer, who is known as the founder of the "Ludwig's Road." + +One would naturally suppose that such an undertaking would have met with +encouragement from the Bavarian Government, but this was not the case. +The starters of the enterprise met with opposition on every side; much +was written against it, and many comic pictures were drawn showing +accidents which would probably occur on the much talked of road. Two of +these pictures are shown in the accompanying large engraving, taken from +the _Illustrirte Zeitung_. As shown in the center picture, right hand, +it was expected by the railway opponents that trains running on tracks +at right angles must necessarily come in collision. If anything happened +to the engine, the passengers would have to get out and push the cars, +as shown at the left. + +[Illustration: JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF THE +OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--AT NURNBERG] + +Much difficulty was experienced in finding an engineer capable of +attending to the construction of the road; and at first it was thought +that it would be best to engage an Englishman, but finally Engineer +Denis, of Munich, was appointed. He had spent much time in England and +America studying the roads there, and carried on this work to the entire +satisfaction of the company. + +All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to be +given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first prize in +the competitive trials at Rainhill in 1829, delivered an engine of ten +horse power, which is still known in Nürnberg as "Der Englander." + +Fifty years have passed, and, as Johannes Scharrer predicted, the +Ludwig's Road has become a permanent institution, though it now forms +only a very small part of the network of railroads which covers every +portion of Germany. What changes have been made in railroads during +these fifty years! Compare the present locomotives with the one made by +Cugnot in 1770, shown in the upper left-hand cut, and with the work of +the pioneer Geo. Stephenson, who in 1825 constructed the first passenger +railroad in England, and who established a locomotive factory in +Newcastle in 1824. Geo. Stephenson was to his time what Mr. Borsig, +whose great works at Moabit now turn out from 200 to 250 locomotives a +year, is to our time. + +Truly, in this time there can be no better occasion for a celebration of +this kind than the fiftieth anniversary of the opening of the first +German railroad, which has lately been celebrated by Nürnberg and Furth. + +The lower left-hand view shows the locomotive De Witt Clinton, the third +one built in the United States for actual service, and the coaches. The +engine was built at the West Point Foundry, and was successfully tested +on the Mohawk and Hudson Railroad between Albany and Schenectady on Aug. +9, 1831. + + * * * * * + + + + +IMPROVED COAL ELEVATOR. + + +An illustration of a new coal elevator is herewith presented, which +presents advantages over any incline yet used, so that a short +description may be deemed interesting to those engaged in the coaling +and unloading of vessels. The pen sketch shows at a glance the +arrangement and space the elevator occupies, taking less ground to do +the same amount of work than any other mode heretofore adopted, and the +first cost of erecting is about the same as any other. + +When the expense of repairing damages caused by the ravages of winter is +taken into consideration, and no floats to pump out or tracks to wash +away, the advantages should be in favor of a substantial structure. + +The capacity of this hoist is to elevate 80,000 bushels in ten hours, at +less than one-half cent per bushel, and put coal in elevator, yard, or +shipping bins. + +[Illustration: IMPROVED COAL ELEVATOR.] + +The endless wire rope takes the cars out and returns them, dispensing +with the use of train riders. + +A floating elevator can distribute coal at any hatch on steam vessels, +as the coal has to be handled but once; the hoist depositing an empty +car where there is a loaded one in boat or barge, requiring no swing of +the vessel. + +Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor and +builder, and has them in use in the U.S. engineering service.--_Coal +Trade Journal_. + + * * * * * + + + + +STEEL-MAKING LADLES. + + +The practice of carrying melted cast iron direct from the blast furnace +to the Siemens hearth or the Bessemer converter saves both money and +time. It has rendered necessary the construction of special plant in the +form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson & +Co., of Preston, make the construction of these ladles a specialty, and +by their courtesy, says _The Engineer_, we are enabled to illustrate +four different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel foundry +work, and one of these for the Siemens-Martin process is illustrated by +Fig. 1. These ladles are made in sizes to take from five to fifteen ton +charges, or larger if required, and are mounted on a very strong +carriage with a backward and forward traversing motion, and tipping gear +for the ladle. The ladles are butt jointed, with internal cover strips, +and have a very strong band shrunk on hot about half way in the depth of +the ladle. This forms an abutment for supporting the ladle in the +gudgeon band, being secured to this last by latch bolts and cotters. The +gearing is made of cast steel, and there is a platform at one end for +the person operating the carriage or tipping the ladle. Stopper gear and +a handle are fitted to the ladles to regulate the flow of the molten +steel from the nozzle at the bottom. + +[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.] + +Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It +requires no description. Fig. 3 shows a tremendous ladle constructed for +the North-Eastern Steel Company, for carrying molten metal from the +blast furnace to the converter. It holds ten tons with ease. It is an +exceptionally strong structure. The carriage frame is constructed +throughout of 1 in. wrought-iron plated, and is made to suit the +ordinary 4 ft. 8½ in. railway gauge. The axle boxes are cast iron, +fitted with gun-metal steps. The wheels are made of forged iron, with +steel tires and axles. The carriage is provided with strong oak buffers, +planks, and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of ½ in. wrought-iron +plates, butt jointed, and double riveted butt straps. The trunnions and +flange couplings are of cast steel. The tipping gear, clearly shown in +the engraving, consists of a worm and wheel, both of steel, which can be +fixed on either side of the ladle as may be desired. From this it will +be seen that Messrs. Stevenson & Co. have made a thoroughly strong +structure in every respect, and one, therefore, that will commend itself +to most steel makers. We understand that these carriages are made in +various designs and sizes to meet special requirements. Thus, Fig. 4 +shows one of different design, made for a steel works in the North. This +is also a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great care +and honesty of purpose is required in making these structures. A +breakdown might any moment pour ten tons of molten metal on the ground, +with the most horrible results. + + * * * * * + + + + +APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE +SURFACE OF CONDUCTORS. + + +Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and +ingenious apparatus which permits of demonstrating that electricity +develops only on the surface of conductors. It consists (see figure) +essentially of a yellow-metal disk, M, fixed to an insulating support, +F, and carrying a concentric disk of ebonite, H. This latter receives a +hollow and closed hemisphere, J, of yellow metal, whose base has a +smaller diameter than that of the disk, H, and is perfectly insulated by +the latter. Another yellow-metal hemisphere, S, open below, is connected +with an insulating handle, G. The basal diameter of this second +hemisphere is such that when the latter is placed over J its edge rests +upon the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a hollow, +closed hemisphere that imprisons the hemisphere, J, which is likewise +hollow and closed, and perfectly insulated from the former. + +[Illustration] + +The shell, S, is provided internally with a curved yellow-metal spring, +whose point of attachment is at B, and whose free extremity is connected +with an ebonite button, K, which projects from the shell, S. By pressing +this button, a contact may be established between the external +hemisphere (formed of the pieces, S and M), and the internal one, J. As +soon as the button is left to itself, the spring again begins to bear +against the interior surface of S, and the two hemispheres are again +insulated. + +The experiment is performed in this wise: The shell, S, is removed. Then +a disk of steatite affixed to an insulating handle is rubbed for a few +instants with a fox's "brush," and held near J until a spark occurs. +Then the apparatus is grasped by the support, F, and an elder-pith ball +suspended by a flaxen thread from a good conducting support is brought +near J. The ball will be quickly repelled, and care must be taken that +it does not come into contact with J. After this the apparatus is placed +upon a table, the shell, S, is taken by its handle, G, and placed in the +position shown in the figure, and a momentary contact is established +between the two hemispheres by pressing the button, K. Then the shell, +S, is lifted, and the disk, M, is touched at the same time with the +other hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, thus +proving that all the electricity passed from J to S at the moment of +contact.--_La Lumiere Electrique_. + + * * * * * + + + + +THE COLSON TELEPHONE. + + +This apparatus has recently been the object of some experiments which +resulted in its being finally adopted in the army. We think that our +readers will read a description of it with interest. Its mode of +construction is based upon a theoretic conception of the lines of force, +which its inventor explains as follows in his Elementary Treatise on +Electricity: + +"To every position of the disk of a magnetic telephone with respect to +the poles of the magnet there corresponds a certain distribution of the +lines of force, which latter shift themselves when the disk is +vibrating. If the bobbin be met by these lines in motion, there will +develop in its wire a difference of potential that, according to +Faraday's law, will be proportional to their number. All things equal, +then, a telephone transmitter will be so much the more potent in +proportion as the lines set in motion by the vibrations of the disk and +meeting the bobbin wire are greater in number. In like manner, a +receiver will be so much the more potent in proportion as the lines of +force, set in motion by variations in the induced currents that are +traversing the bobbin and meeting the disk, are more numerous. It will +consequently be seen that, generally speaking, it is well to send as +large a number of lines of force as possible through the bobbin." + +[Illustration: FIG. 1.--THE COLSON TELEPHONE.] + +In order to obtain such a result, the thin tin-plate disk has to be +placed between the two poles of the magnet. The pole that carries the +fine wire bobbin acts at one side and in the center of the disk, while +the other is expanded at the extremity and acts upon the edge and the +other side. This pole is separated from the disk by a copper washer, and +the disk is thus wholly immersed in the magnetic field, and is traversed +by the lines of force radiatingly. + +This telephone is being constructed by Mr. De Branville, with the +greatest care, in the form of a transmitter (Fig. 2) and receiver (Fig. +3). At A may be seen the magnet with its central pole, P, and its +eccentric one, P'. This latter traverses the vibrating disk, M, through +a rubber-lined aperture and connects with the soft iron ring, F, that +forms the polar expansion. These pieces are inclosed in a nickelized +copper box provided with a screw cap, C. The resistance of both the +receiver and transmitter bobbin is 200 ohms. + +[Illustration: FIG. 2.--TRANSMITTER TAKEN APART.] + +The transmitter is 3½ in. in diameter, and is provided with a +re-enforcing mouthpiece. It is regulated by means of a screw which is +fixed in the bottom of the box, and which permits of varying the +distance between the disk and the core that forms the central pole of +the magnet. The regulation, when once effected, lasts indefinitely. The +regulation of the receiver, which is but 2¼ in. in diameter, is +performed once for all by the manufacturer. One of the advantages of +this telephone is that its regulation is permanent. Besides this, it +possesses remarkable power and clearness, and is accompanied with no +snuffling sounds, a fact doubtless owing to all the molecules of the +disk being immersed in the magnetic field, and to the actions of the two +poles occurring concentrically with the disk. As we have above said, +this apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used by +the artillery service in the organization of observatories from which to +watch firing, and the receiver is added to the apparatus pertaining to +military telegraphy. The two small receivers are held to the lens of the +operator by the latter's hat strap, while the transmitter is suspended +in a case supported by straps, with the mouthpieces near the face (Fig. +1). + +In the figure, the case is represented as open, so as to show the +transmitter. The empty compartment below is designed for the reception +and carriage of the receivers, straps, and flexible cords. This +arrangement permits of calling without the aid of special apparatus, and +it has also the advantage of giving entire freedom to the man on +observation, this being something that is indispensable in a large +number of cases. + +[Illustration: FIG. 3.--RECEIVER TAKEN APART.] + +In certain applications, of course, the receivers may be combined with a +microphone; yet on an aerial as well as on a subterranean line the +transmitter produces effects which, as regards intensity and clearness, +are comparable with those of a pile transmitter. + +Stations wholly magnetic may be established by adding to the transmitter +and two receivers a Sieur phonic call, which will actuate them +powerfully, and cause them to produce a noise loud enough for a call. It +would be interesting to try this telephone on a city line, and to a +great distance on those telegraph lines that are provided with the Van +Rysselberghe system. Excellent results would certainly be obtained, for, +as we have recently been enabled to ascertain, the voice has a +remarkable intensity in this telephone, while at the same time perfectly +preserving its quality.--_La Nature_. + + * * * * * + +[NATURE.] + + + + +THE MELDOMETER. + + +The apparatus which I propose to call by the above name +([mu][epsilon][lambda][delta][omega], to melt) consists of an adjunct to +the mineralogical microscope, whereby the melting-points of minerals may +be compared or approximately determined and their behavior watched at +high temperatures either alone or in the presence of reagents. + +As I now use it, it consists of a narrow ribbon of platinum (2 mm. wide) +arranged to traverse the field of the microscope. The ribbon, clamped in +two brass clamps so as to be readily renewable, passes bridgewise over a +little scooped-out hollow in a disk of ebony (4 cm. diam.). The clamps +also take wires from a battery (3 Groves cells); and an adjustable +resistance being placed in circuit, the strip can be thus raised in +temperature up to the melting-point of platinum. + +The disk being placed on the stage of the microscope the platinum strip +is brought into the field of a 1" objective, protected by a glass slip +from the radiant heat. The observer is sheltered from the intense light +at high temperatures by a wedge of tinted glass, which further can be +used in photometrically estimating the temperature by using it to obtain +extinction of the field. Once for all approximate estimations of the +temperature of the field might be made in terms of the resistance of the +platinum strip, the variation of such resistance with rise of +temperature being known. Such observations being made on a suitably +protected strip might be compared with the wedge readings, the latter +being then used for ready determinations. Want of time has hindered me +from making such observations up to this. + +The mineral to be experimented on is placed in small fragments near the +center of the platinum ribbon, and closely watched while the current is +increased, till the melting-point of the substance is apparent. Up to +the present I have only used it comparatively, laying fragments of +different fusibilities near the specimen. In this way I have melted +beryl, orthoclase, and quartz. I was much surprised to find the last +mineral melt below the melting-point of platinum. I have, however, by me +as I write, a fragment, formerly clear rock-crystal, so completely fused +that between crossed Nicols it behaves as if an amorphous body, save in +the very center where a speck of flashing color reveals the remains of +molecular symmetry. Bubbles have formed in the surrounding glass. + +Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way. + +Topaz whitens to a milky glass--apparently decomposing, throwing out +filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot platinum, +causes rings of color to appear round the specimen. I have now been +using the apparatus for nearly a month, and in its earliest days it led +me right in the diagnosis of a microscopical mineral, iolite, not before +found in our Irish granite, I think. The unlooked-for characters of the +mineral, coupled with the extreme minuteness of the crystals, led me +previously astray, until my meldometer fixed its fusibility for me as +far above the suspected bodies. + +Carbon slips were at first used, as I was unaware of the capabilities of +platinum. + +A form of the apparatus adapted, at Prof. Fitzgerald's suggestion, to +fit into the lantern for projection on the screen has been made for me +by Yeates. In this form the heated conductor passes both below and above +the specimen, which is regarded from a horizontal direction. + +J. JOLY. + +Physical Laboratory, Trinity College, Dublin. + + * * * * * + +[AMERICAN ANNALS OF THE DEAF AND DUMB.] + + + + +TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF DEAF-MUTES. + + +Progress in electrical science is daily causing the world to open its +eyes in wonder and the scientist to enlarge his hopes for yet greater +achievements. The practical uses to which this subtile fluid, +electricity, is being put are causing changes to be made in time-tested +methods of doing things in domestic, scientific, and business circles, +and the time has passed when startling propositions to accomplish this +or that by the assistance of electricity are dismissed with incredulous +smiles. This being the case, no surprise need follow the announcement of +a device to facilitate the imparting of instruction to deaf children +which calls into requisition some service from electricity. + +The sense of touch is the direct medium contemplated, and it is intended +to convey, with accuracy and rapidity, messages from the operator (the +teacher) to the whole class simultaneously by electrical +transmission.[1] + +[Footnote 1: By the same means two deaf-mutes, miles apart, might +converse with each other, and the greatest difficulty in the way of a +deaf-mute becoming a telegraph operator, that of receiving messages, +would be removed. The latter possibilities are incidentally mentioned +merely as of scientific interest, and not because of their immediate +practical value. The first mentioned use to which the device may be +applied is the one considered by the writer as possibly of practical +value, the consideration of which suggested the appliance to him.] + +An alphabet is formed upon the palm of the left hand and the inner side +of the fingers, as shown by the accompanying cut, which, to those +becoming familiar with it, requires but a touch upon a certain point of +the hand to indicate a certain letter of the alphabet. + +A rapid succession of touches upon various points of the hand is all +that is necessary in spelling a sentence. The left hand is the one upon +which the imaginary alphabet is formed, merely to leave the right hand +free to operate without change of position when two persons only are +conversing face to face. + +The formation of the alphabet here figured is on the same principle as +one invented by George Dalgarno, a Scottish schoolmaster, in the year +1680, a cut of which maybe seen on page 19 of vol. ix. of the _Annals_, +accompanying the reprint of a work entitled "_Didascalocophus_." +Dalgarno's idea could only have been an alphabet to be used in +conversation between two persons _tête à tête_, and--except to a limited +extent in the Horace Mann School and in Professor Bell's teaching--has +not come into service in the instruction of deaf-mutes or as a means of +conversation. There seems to have been no special design or system in +the arrangement of the alphabet into groups of letters oftenest +appearing together, and in several instances the proximity would +seriously interfere with distinct spelling; for instance, the group "u," +"y," "g," is formed upon the extreme joint of the little finger. The +slight discoverable system that seems to attach to his arrangement of +the letters is the placing of the vowels in order upon the points of the +fingers successively, beginning with the thumb, intended, as we suppose, +to be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly as +another. If any arrangement has advantage over another, we consider it +the one which has so grouped the letters as to admit of an increased +rapidity of manipulation. The arrangement of the above alphabet, it is +believed, does admit of this. Yet it is not claimed that it is as +perfect as the test of actual use may yet make it. Improvements in the +arrangement will, doubtless, suggest themselves, when the alterations +can be made with little need of affecting the principle. + +In order to transmit a message by this alphabet, the following described +appliance is suggested: A matrix of cast iron, or made of any suitable +material, into which the person receiving the message (the pupil) places +his left hand, palm down, is fixed to the table or desk. The matrix, +fitting the hand, has twenty-six holes in it, corresponding in position +to the points upon the hand assigned to the different letters of the +alphabet. In these holes are small styles, or sharp points, which are so +placed as but slightly to touch the hand. Connected with each style is a +short line of wire, the other end of which is connected with a principal +wire leading to the desk of the operator (the teacher), and there so +arranged as to admit of opening and closing the circuit of an electric +current at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric impulses, +intended to act mechanically upon all the styles connected with it. By +these impulses, produced by the will of the sender, the styles are +driven upward with a quick motion, but with only sufficient force to be +felt and located upon the hand by the recipient. Twenty-six of these +principal or primary wires are run from the teacher's desk (there +connected with as many buttons) under the floor along the line of +pupils' desks. From each matrix upon the desk run twenty-six secondary +wires down to and severally connecting with the twenty-six primary wires +under the floor. The whole system of wires is incased so as to be out of +sight and possibility of contact with foreign substances. The keys or +buttons upon the desk of the teacher are systematically arranged, +somewhat after the order of those of the type writer, which allows the +use of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," "c," +etc., to "z," and an electric current over the primary wire running from +a certain button (say the one labeled "a") affects only those secondary +wires connected with the styles that, when excited, produce upon the +particular spot of the hands of the receivers the tactile impression to +be interpreted as "a." And so, whenever the sender touches any of the +buttons on his desk, immediately each member of the class feels upon the +palm of his hand the impression meant to be conveyed. The contrivance +will admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric bell. +It was first thought of conveying the impressions directly by slight +electric shocks, without the intervention of further mechanical +apparatus, but owing to a doubt as to the physical effect that might be +produced upon the persons receiving, and as to whether the nerves might +not in time become partly paralyzed or so inured to the effect as to +require a stronger and stronger current, that idea was abandoned, and +the one described adopted. A diagram of the apparatus was submitted to a +skillful electrical engineer and machinist of Hartford, who gave as his +opinion that the scheme was entirely feasible, and that a simple and +comparatively inexpensive mechanism would produce the desired result. + +[Illustration: TOUCH TRANSMISSION BY ELECTRICITY.] + +The matter now to consider, and the one of greater interest to the +teacher of deaf children, is, Of what utility can the device be in the +instruction of deaf-mutes? What advantage is there, not found in the +prevailing methods of communication with the deaf, i.e., by gestures, +dactylology, speech and speech-reading, and writing? + +I. The language of gestures, first systematized and applied to the +conveying of ideas to the deaf by the Abbe de l'Epee during the latter +part of the last century, has been, in America, so developed and +improved upon by Gallaudet, Peet, and their successors, as to leave but +little else to be desired for the purpose for which it was intended. The +rapidity and ease with which ideas can be expressed and understood by +this "language" will never cease to be interesting and wonderful, and +its value to the deaf can never fail of being appreciated by those +familiar with it. But the genius of the language of signs is such as to +be in itself of very little, if any, direct assistance in the +acquisition of syntactical language, owing to the diversity in the order +of construction existing between the English language and the language +of signs. Sundry attempts have been made to enforce upon the +sign-language conformity to the English order, but they have, in all +cases known to the writer, been attended with failure. The sign-language +is as immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given with +great success upon the basis of the sign-language. But in all such +exercises there must be a translation from one language to the other. +The desideratum still exists of an increased percentage of pupils +leaving our schools for the deaf, possessing a facility of expression in +English vernacular. This want has been long felt, and endeavoring to +find a reason for the confessedly low percentage, the sign-language has +been too often unjustly accused. It is only when the sign-language is +abused that its merit as a means of instruction degenerates. The most +ardent admirers of a proper use of signs are free to admit that any +excessive use by the pupils, which takes away all opportunities to +express themselves in English, is detrimental to rapid progress in +English expression. + +II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as one +of the elements of the American or eclectic method. This advantage, +however, is not of so great importance as to outweigh the disadvantages +when, as has honestly been attempted, it asserts its independence of +other methods. Very few persons indeed, even after long practice, become +sufficiently skillful in spelling on the fingers to approximate the +rapidity of speech. But were it possible for all to become rapid +spellers, another very important requisite is necessary before the +system could be a perfect one, that is, the ability to _read_ rapid +spelling. The number of persons capable of reading the fingers beyond a +moderate degree of rapidity is still less than the number able to spell +rapidly. While it is physically possible to follow rapid spelling for +twenty or thirty minutes, it can scarcely be followed longer than that. +So long as this is true, dactylology can hardly claim to be more than +one of the _elements_ of a system of instruction for the deaf. + +III. Articulate speech is another of the elements of the eclectic +method, employed with success inversely commensurate with the degree of +deficiency arising from deafness. Where the English order is already +fixed in his mind, and he has at an early period of life habitually used +it, there is comparatively little difficulty in instructing the deaf +child by speech, especially if he have a quick eye and bright intellect. +But the number so favored is a small percentage of the great body of +deaf-mutes whom we are called upon to educate. When it is used as a +_sole_ means of educating the deaf as a class its inability to stand +alone is as painfully evident as that of any of the other component +parts of the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to what +a word is if spelled slowly enough, and if its meaning has been learned. +This cannot be said of speech. Between many words there is not, when +uttered, the slightest visible distinction. Between a greater number of +others the distinction is so slight as to cause an exceedingly nervous +hesitation before a guess can be given. Too great an imposition is put +upon the eye to expect it to follow unaided the extremely circumscribed +gestures of the organs of speech visible in ordinary speaking. The ear +is perfection as an interpreter of speech to the brain. It cannot +correctly be said that it is _more_ than perfection. It is known that +the ear, in the interpretation of vocal sounds, is capable of +distinguishing as many as thirty-five sounds per second (and oftentimes +more), and to follow a speaker speaking at the rate of more than two +hundred words per minute. If this be perfection, can we expect the _eye_ +of ordinary mortal to reach it? Is there wonder that the task is a +discouraging one for the deaf child? + +But it has been asserted that while a large percentage (practically all) +of the deaf _can_, by a great amount of painstaking and practice, become +speech readers in some small degree, a relative degree of facility in +articulation is not nearly so attainable. As to the accuracy of this +view, the writer cannot venture an opinion. Judging from the average +congenital deaf-mute who has had special instruction in speech, it can +safely be asserted that their speech is laborious, and far, very far, +from being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that as an +unaided means of instruction it cannot be a success, for English neither +understood when spoken, nor spoken by the pupil, cannot but remain a +foreign language, requiring to pass through some other form of +translation before it becomes intelligible. + +There are the same obstacles in the use of the written or printed word +as have been mentioned in connection with dactylology, namely, lack of +rapidity in conveying impressions through the medium of the English +sentence. + +I have thus hastily reviewed the several means which teachers generally +are employing to impart the use of English to deaf pupils, for the +purpose of showing a common difficulty. The many virtues of each have +been left unnoticed, as of no pertinence to this article. + +The device suggested at the beginning of this paper, claiming to be +nothing more than a school room appliance intended to supplement the +existing means for giving a knowledge and practice of English to the +deaf, employs as its interpreter a different sense from the one +universally used. The sense of sight is the sole dependence of the deaf +child. Signs, dactylology, speech reading, and the written and printed +word are all dependent upon the eye for their value as educational +instruments. It is evident that of the two senses, sight and touch, if +but one could be employed, the choice of sight as the one best adapted +for the greatest number of purposes is an intelligent one; but, as the +choice is not limited, the question arises whether, in recognizing the +superior adaptability to our purpose of the one, we do not lose sight of +a possibly important, though secondary, function in the other. If sight +were all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we acquire +our vernacular is of divine, and not of human, origin, and the senses +designed for special purposes are not interchangeable without loss. The +theory that the loss of a certain sense is nearly, if not quite, +compensated for by increased acuteness of the remaining ones has been +exploded. Such a theory accuses, in substance, the Maker of creating +something needless, and is repugnant to the conceptions we have of the +Supreme Being. When one sense is absent, the remaining senses, in order +to equalize the loss, have imposed upon them an unusual amount of +activity, from which arises skill and dexterity, and by which the loss +of the other sense is in some measure alleviated, but not supplied. No +_additional_ power is given to the eye after the loss of the sense of +hearing other than it might have acquired with the same amount of +practice while both faculties were active. The fact, however, that the +senses, in performing their proper functions, are not overtaxed, and are +therefore, in cases of emergency, capable of being extended so as to +perform, in various degrees, additional service, is one of the wise +providences of God, and to this fact is due the possibility of whatever +of success is attained in the work of educating the deaf, as well as the +blind. + +In the case of the blind, the sense of touch is called into increased +activity by the absence of the lost sense; while in the case of the +deaf, sight is asked to do this additional service. A blind person's +education is received principally through the _two_ senses of hearing +and touch. Neither of these faculties is so sensible to fatigue by +excessive use as is the sense of sight, and yet the eye has, in every +system of instruction applied to the deaf, been the sole medium. In no +case known to the writer, excepting in the celebrated case of Laura +Bridgman and a few others laboring under the double affliction of +deafness and blindness, has the sense of touch been employed as a means +of instruction.[1] + +[Footnote 1: This article was written before Professor Bell had made his +interesting experiments with his "parents' class" of a touch alphabet, +to be used upon the pupil's shoulder in connection with the oral +teaching.--E.A.F.] + +Not taking into account the large percentage of myopes among the deaf, +we believe there are other cogent reasons why, if found practicable, the +use of the sense of touch may become an important element in our +eclectic system of teaching. We should reckon it of considerable +importance if it were ascertained that a portion of the same work now +performed by the eye could be accomplished equally as well through +feeling, thereby relieving the eye of some of its onerous duties. + +We see no good reason why such accomplishment may not be wrought. If, +perchance, it were discovered that a certain portion could be performed +in a more efficient manner, its value would thus be further enhanced. + +In theory and practice, the teacher of language to the deaf, by whatever +method, endeavors to present to the eye of the child as many completed +sentences as are nominally addressed to the ear--having them "caught" by +the eye and reproduced with as frequent recurrence as is ordinarily done +by the child of normal faculties. + +In our hasty review of the methods now in use we noted the inability to +approximate this desirable process as a common difficulty. The facility +now ordinarily attained in the manipulation of the type writer, and the +speed said to have been reached by Professor Bell and a private pupil of +his by the Dalgarno touch alphabet, when we consider the possibility of +a less complex mechanism in the one case and a more systematic grouping +of the alphabet in the other, would lead us to expect a more rapid means +of communication than is ordinarily acquired by dactylology, speech (by +the deaf), or writing. Then the ability to receive the communication +rapidly by the sense of feeling will be far greater. No part of the body +except the point of the tongue is as sensible to touch as the tips of +the fingers and the palm of the hand. Tactile discrimination is so acute +as to be able to interpret to the brain significant impressions produced +in very rapid succession. Added to this advantage is the greater one of +the absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the tympanum of +the ear. To sum up, then, the advantages of the device we find-- + +First. A more rapid means of communication with the deaf by syntactic +language, admitting of a greater amount of practice similar to that +received through the ear by normal children. + +Second. Ability to receive this rapid communication for a longer +duration and without ocular strain. + +Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender. + +Fourth. In articulation and speech-reading instruction, the power to +assist a class without distracting the attention of the eye from the +vocal organs of the teacher. + +Fifth. Freedom of the right hand of the pupil to make instantaneous +reproduction in writing of the matter being received through the sense +of feeling, thereby opening the way for a valuable class exercise. + +Sixth. The possible mental stimulus that accompanies the mastery of a +new language, and the consequent ability to receive known ideas through +a new medium. + +Seventh. A fresh variety of class exercises made possible. + +The writer firmly believes in the good that exists in all methods that +are, or are to be; in the interdependence rather than the independence +of all methods; and in all school-room appliances tending to supplement +or expedite the labors of the teacher, whether they are made of +materials delved from the earth or snatched from the clouds. + +S. TEFFT WALKER, + +_Superintendent of the Kansas Institution, Olathe, Kans_. + + * * * * * + + + + +WATER GAS. + +THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON REDUCING AGENTS. + +By B.H. THWAITE. + + +In order to approximately ascertain the relative reducing action of +water gas, carbon monoxide, and superheated steam on iron ore, the +author decided to have carried out the following experiments, which were +conducted by Mr. Carl J. Sandahl, of Stockholm, who also carried out the +analyses. The ore used was from Bilbao, and known as the Ruby Mine, and +was a good average hematite. The carbonaceous material was the Trimsaran +South Wales anthracite, and contained about 90 per cent. of carbon. + +A small experimental furnace was constructed of the form shown by +illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the base, +and gradually swelling to 2 ft. 9 in. at the top, built entirely of +fireclay bricks. Two refractory tubes, 2 in. square internally, and the +height of the furnace, were used for the double purpose of producing the +gas and reducing the ore. + +The end of the lower tube rested on a fireclay ladle nozzle, and was +properly jointed with fireclay; through this nozzle the steam or air was +supplied to the inside of the refractory tubes. In each experiment the +ore and fuel were raised to the temperature "of from 1,800 to 2,200 deg. +Fahr." by means of an external fire of anthracite. Great care was taken +to prevent the contact of the solid carbonaceous fuel with the ore. In +each experiment in which steam was used, the latter was supplied at a +temperature equivalent to 35 lb. to the square inch. + +The air for producing the carbon monoxide (CO) gas was used at the +temperature of the atmosphere. As near as possible, the same conditions +were obtained in each experiment, and the equivalent weight of air was +sent through the carbon to generate the same weight of CO as that +generated when steam was used for the production of water gas. + +[Illustration] + +_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled +with ore broken to the size of nuts. The tube, A, was heated to about +2,000 deg. Fahr., the upper one to about 1,500 deg. + +NOTE.--In this experiment, part of the steam was dissociated in passing +through the turned-up end of the steam supply pipe, which became very +hot, and the steam would form with the iron the magnetic oxide +(Fe_{3}O_{4}). The reduction would doubtless be due to this +dissociation. The pieces of ore found on lowest end of the tube, A, were +dark colored and semi-fused; part of one of these pieces was crushed +fine, and tested; see column I. The remainder of these black pieces was +mixed with the rest of the ore contained in tube, A, and ground and +tested; see column II. The ore in upper tube was all broken up together +and tested; see column III. When finely crushed, the color of No. I. was +bluish black; No. II., a shade darker red; No. III., a little darker +than the natural color of the ore. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- + +_Second Experiment, Water Gas_.--The tube, A, was filled with small +pieces of anthracite, and heated until all the volatile matter had been +expelled. The tube, B, was then placed in tube, A, the joint being made +with fireclay, and to prevent the steam from carrying small particles of +solid carbon into ore in the upper tube, the anthracite was divided from +the ore by means of a piece of fine wire gauze. The steam at a pressure +of about 35 lb. to the square inch was passed through the anthracite. +The tube, A, was heated to white heat, the tube, B, at its lower end to +bright red, the top to cherry red. + +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ + +_Four Samples were Tested_.--I. The bottom layer, 1¼ in. thick; the +color of ore quite black, with small particles of reduced spongy +metallic iron. II. Layer above I., 4¼ in. thick; the color was also +black, but showed a little purple tint. III. Layer above II., 5 in. +thick; purple red color. IV. Layer above III., ore a red color. The +analyses gave: + +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- + +NOTE.--All the carbon dioxide (CO_{2}) occurring in the ore as calcic +carbonate was expelled. + +_Third Experiment, Carbon monoxide_ (CO).--The tube A was filled with +anthracite in the manner described for the second experiment, and heated +to drive off the volatile matter, before the ore was placed in the upper +tube, B, and the anthracite was divided from the ore by means of a piece +of fine wire gauze. The lower tube, A, was heated to the temperature of +white heat, the upper one, B, to a temperature of bright red. I. Layer, +1 in. thick from the bottom; ore dark brownish colored. II. Layer 4 in. +thick above I.; ore reddish brown. III. Layer 11 in. thick above II.; +ore red color. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- + +NOTE.--The carbon monoxide (CO) had failed to remove from the ore the +carbon dioxide existing as calcic carbonate. The summary of experiments +in the following table appears to show that the water gas is a more +powerful reducing agent than CO in proportion to the ratio of as + + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 + +Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just now +constructing large experimental plant in which water gas will be used as +the reducing agent. This plant would have been at work before this but +for some defects in the valvular arrangements, which will be entirely +removed in the new modifications of the plant. + + * * * * * + + + + +ANTISEPTIC MOUTH WASH. + + +Where an antiseptic mouth wash is needed, Mr. Sewill prescribes the use +of perchloride of mercury in the following form: One grain of the +perchloride and 1 grain of chloride of ammonium to be dissolved in 1 oz. +of eau de Cologne or tincture of lemons, and a teaspoonful of the +solution to be mixed with two-thirds of a wineglassful of water, making +a proportion of about 1 of perchloride in 5,000 parts.--_Chemist and +Druggist_. + + * * * * * + + + + +ANNATTO. + +[Footnote: Read at an evening meeting of the North British Branch of the +Pharmaceutical Society, January 21.] + +By WILLIAM LAWSON. + + +The subject which I have the honor to bring shortly before your notice +this evening is one that formed the basis of some instructive remarks by +Dr. Redwood in November, 1855, and also of a paper by Dr. Hassall, read +before the Society in London in January, 1856, which latter gave rise to +an animated discussion. The work detailed below was well in hand when +Mr. MacEwan drew my attention to these and kindly supplied me with the +volume containing reports of them. Unfortunately, they deal principally +with the adulterations, while I was more particularly desirous to learn +the composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. Within +the last few years it was one of the articles in considerable demand in +this part of the country; now it is seldom inquired for. This, +certainly, is not because butter coloring has ceased to be employed, and +hence the reason for regretting that the percentage of resin was not +dealt with in the articles referred to, so that a comparison could have +been made between the commercial annatto of that period and that which +exists now. In case some may not be in possession of literature bearing +on it--which, by the way, is very meager--it may not be out of place to +quote some short details as to its source, the processes for obtaining +it, the composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has more +interest for the country than for the town druggist, still, I trust it +will have points of interest for both. + +Annatto is the coloring matter derived from the seeds of an evergreen +plant, _Bixa Orellana_, which grows in the East and West Indian Islands +and South America, in the latter of which it is principally prepared. +Two kinds are imported, Spanish annatto, made in Brazil, and flag or +French, made mostly in Cayenne. These differ considerably in characters +and properties, the latter having a disagreeable putrescent odor, while +the Spanish is rather agreeable when fresh and good. It is, however, +inferior to the flag as a coloring or dyeing agent. The seeds from which +the substance is obtained are red on the outside, and two methods are +followed in order to obtain it. One is to rub or wash off the coloring +matter with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to bruise +the seeds, mix them with water, and allow fermentation to set in, during +which the coloring matter collects at the bottom, from which it is +subsequently removed and brought to the proper consistence by +spontaneous evaporation. These particulars, culled from Dr. Redwood's +remarks, may suffice to show its source and the methods for obtaining +it. + +Dr. John gives the following as the composition of the pulp surrounding +the seeds: Coloring resinous matter, 28; vegetable gluten, 26.5; +ligneous fiber, 20; coloring, 20; extractive matter, 4; and a trace of +spicy and acid matter. + +It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as well as +to preserve it, differs considerably from this; and though it may not be +true, as some hint, that manufacturing in this industry is simply a term +synonymous with adulterating, yet results will afterward be given +tending to show that there are articles in the market which have little +real claim to the title. I tried, but failed, to procure a sample of raw +material on which to work, with a view to learn something of its +characters and properties in this state, and thus be able to contrast it +with the manufactured or commercial article. The best thing to do in the +circumstances, I thought, was to operate on the highest priced sample at +disposal, and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the usual +way, I believe--was a more troublesome operation than it appeared to be, +as the following experiment will show: One hundred grains of No. 8 were +taken, dried thoroughly, reduced to fine powder, and introduced into a +flask containing 4 ounces of alcohol in the form of methylated spirit, +boiled for an hour--the flask during the operation being attached to an +inverted condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated with +diminishing quantities until in all 14 ounces had been used before the +alcoholic solution ceased to turn blue on the addition to it of strong +sulphuric acid, or failed to give a brownish precipitate with stannous +chloride. As the sample contained a considerable quantity of potassium +carbonate, in which the resin is soluble, it was thought that by +neutralizing this it might render the resin more easy of extraction. +This was found to be so, but it was accompanied by such a mass of +extractive as made it in the long run more troublesome, and hence it was +abandoned. Thinking the spirit employed might be too weak, an experiment +with commercial absolute alcohol was carried out as follows: One hundred +grains of a red sample, No. 4, were thoroughly dried, powdered finely, +and boiled in 2 ounces of the alcohol, filtered, and the residue treated +with half an ounce more. This required to be repeated with fresh half +ounces of the alcohol until in all 7½ were used; the time occupied from +first to last being almost three hours. This was considered +unsatisfactory, besides being very expensive, and so it, also, was set +aside, and a series of experiments with methylated spirit alone was set +in hand. The results showed that the easiest and most satisfactory way +was to take 100 grains (this amount being preferred, as it reduces error +to the minimum), dry thoroughly, powder finely, and macerate with +frequent agitation for twenty-four hours in a few ounces of spirit, then +to boil in this spirit for a short time, filter, and repeat the boiling +with a fresh ounce or so; this, as a rule, sufficing to completely +exhaust it of its resin. Wynter Blyth says that the red resin, or bixin, +is soluble in 25 parts of hot alcohol. It appears from these experiments +that much more is required to dissolve it out of commercial annatto. + +The full process followed consisted in determining the moisture by +drying 100 grains at 212° F. till constant, and taking this dried +portion for estimation of the resin in the way just stated. The +alcoholic extract was evaporated to dryness over a water-bath, the +residue dissolved in solution of sodium carbonate, and the resin +precipitated by dilute sulphuric acid (these reagents being chosen as +the best after numerous trials with others), added in the slightest +possible excess. The resin was collected on a tared double filter paper, +washed with distilled water until the washings were entirely colorless, +dried and weighed. + +The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of them. + +The results are as follows: + + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 + +The first six are the ordinary red rolls, with the exception of No. 4, +which is a red mass, the only one of this class direct from the +manufacturers. The remainder are brown cakes, all except No. 7 being +from the manufacturers direct. The ash of the first two was largely +common salt; that of No. 3 contained, besides this, iron in some +quantity. No. 4 is unique in many respects. It was of a bright red +color, and possessed a not disagreeable odor. It contained the largest +percentage of moisture and the lowest of ash; had, comparatively, a +large amount of coloring matter; was one of the cheapest, and in the +course of some dairy trials, carried out by an intelligent farmer, was +pronounced to be the best suited for coloring butter. So far as my +experience goes, it was a sample of the best commercial excellence, +though I fear the mass of water present and the absence of preserving +substances will assist in its speedy decay. Were such an article easily +procured in the usual way of business, there would not be much to +complain of, but it must not be forgotten that it was got direct from +the manufacturers--a somewhat suggestive fact when the composition of +some other samples is taken into account. No. 5 emitted a disagreeable +odor during ignition. The soluble portion of the ash was mostly common +salt, and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter gave +rise to disagreeable reflections. It was wrapped in a paper saturated +with a strongly smelling linseed oil. When it was boiled in water and +broken up, hairs, among other things, were observed floating about. It +contained some iron. The first cake, No. 7, gave off during ignition an +agreeable odor resembling some of the finer tobaccos, and this is +characteristic more or less of all the cakes. The ash weighed 52 per +cent., the soluble part of which, 18.5, was mostly potassium carbonate, +with some chlorides and sulphates; the insoluble, mostly chalk with iron +and alumina. No. 8--highest priced of all--had in the mass an odor which +I can compare to nothing else than a well rotted farmyard manure. Twenty +parts of the ash were soluble and largely potassium carbonate, the +insoluble being iron for the most part. The mineral portions of Nos. 9 +and 10 closely resemble No. 7. + +On looking over the results, it is found that the red rolls contained +starchy matters in abundance (in No. 4 the starch was to a large extent +replaced by water), and an ash, mostly sodium chloride, introduced no +doubt to assist in its preservation as well as to increase the color of +the resin--a well known action of salt on vegetable reds. The cakes, +which are mostly used for cheese coloring, I believe, all appeared to +contain turmeric, for they gave a more or less distinct reaction with +the boric acid test, and all except No. 8 contained large quantities of +chalk. These results in reference to extractive, etc., reveal nothing +that has not been known before. Wynter Blyth, who gives the only +analyses of annatto I have been able to find, states that the +composition of a fair commercial sample (which I take to mean the raw +article) examined by him was as follows: water, 24.2; resin, 28.8; ash, +22.5; and extractive, 24.5; and that of an adulterated (which I take to +mean a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. 27.3. If +this be correct, it appears that the articles at present in the market, +or at least those which have come in my way, have been wretched +imitations of the genuine thing, and should, instead of being called +adulterated annatto, be called something else adulterated, but not +seriously, with annatto. I have it on the authority of the farmer +previously referred to, that ¼ of an ounce of No. 4 is amply sufficient +to impart the desired cowslip tint to no less than 60 lb. of butter. +When so little is actually required, it does not seem of very serious +importance whether the adulterant or preservative be flour, chalk, or +water, but it is exasperating in a very high degree to have such +compounds as Nos. 3 and 6 palmed off as decent things when even Nos. 1, +2, and 5 have been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may be +induced to examine the annatto taken into stock more closely than I was +taught to do, and had been in the habit of doing, namely, to see if it +had a good consistence and an odor resembling black sugar, for if so, +the quality was above suspicion. + + * * * * * + + + + +JAPANESE RICE WINE AND SOJA SAUCE. + + +Professor P. Cohn has recently described the mode in which he has +manufactured the Japanese sake or rice wine in the laboratory. The +material used was "Tane Kosi," i.e., grains of rice coated with the +mycelium, conidiophores, and greenish yellow chains of conidia of +_Aspergillus Oryzoe_. The fermentation is caused by the mycelium of this +fungus before the development of the fructification. The rice is first +exposed to moist air so as to change the starch into paste, and then +mixed with grains of the "Tane Kosi." The whole mass of rice becomes in +a short time permeated by the soft white shining mycelium, which imparts +to it the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two or +three days, and then subjected to alcoholic fermentation from the +_Saccharomyces_, which is always present in the rice, but which has +nothing to do with the _Aspergillus_. The fermentation is completed in +two or three weeks, and the golden yellow, sherry-like sake is poured +off. The sample manufactured contained 13.9 per cent. of alcohol. +Chemical investigation showed that the _Aspergillus_ mycelium transforms +the starch into glucose, and thus plays the part of a diastase. + +Another substance produced from the _Aspergillus_ rice is the soja +sauce. The soja leaves, which contain little starch, but a great deal of +oil and casein, are boiled, mixed with roasted barley, and then with the +greenish yellow conidia powder of the _Aspergillus_. After the mycelium +has fructified, the mass is treated with a solution of sodium chloride, +which kills the _Aspergillus_, another fungus, of the nature of a +_Chalaza_, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce then +separates. + + * * * * * + + + + +ALUMINUM. + +[Footnote: Annual address delivered by President J.A. Price before the +meeting of the Scranton Board of Trade, Monday, January 18, 1886.] + +By J.A. PRICE. + + +Iron is the basis of our civilization. Its supremacy and power it is +impossible to overestimate; it enters every avenue of development, and +it may be set down as the prime factor in the world's progress. Its +utility and its universality are hand in hand, whether in the +magnificent iron steamship of the ocean, the network of iron rail upon +land, the electric gossamer of the air, or in the most insignificant +articles of building, of clothing, and of convenience. Without it, we +should have miserably failed to reach our present exalted station, and +the earth would scarcely maintain its present population; it is indeed +the substance of substances. It is the Archimedean lever by which the +great human world has been raised. Should it for a moment forget its +cunning and lose its power, earthquake shocks or the wreck of matter +could not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that it +must give way to a metal that has still greater proportions and vaster +possibilities. Strange and startling as may seem the assertion, yet I +believe it nevertheless to be true that we are approaching the period, +if not already standing upon the threshold of the day, when this magical +element will be radically supplanted, and when this valuable mineral +will be as completely superseded as the stone of the aborigines. With +all its apparent potency, it has its evident weaknesses; moisture is +everywhere at war with it, gases and temperature destroy its fiber and +its life, continued blows or motion crystallize and rob it of its +strength, and acids will devour it in a night. If it be possible to +eliminate all, or even one or more, of these qualities of weakness in +any metal, still preserving both quantity and quality, that metal will +be the metal of the future. + +The coming metal, then, to which our reference is made is aluminum, the +most abundant metal in the earth's crust. Of all substances, oxygen is +the most abundant, constituting about one-half; after oxygen comes +silicon, constituting about one-fourth, with aluminum third in all the +list of substances of the composition. Leaving out of consideration the +constituents of the earth's center, whether they be molten or gaseous, +more or less dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we find +that aluminum is beyond question the most abundant and the most useful +of all metallic substances. + +It is the metallic base of mica, feldspar, slate, and clay. Professor +Dana says: "Nearly all the rocks except limestones and many sandstones +are literally ore-beds of the metal aluminum." It appears in the gem, +assuming a blue in the sapphire, green in the emerald, yellow in the +topaz, red in the ruby, brown in the emery, and so on to the white, +gray, blue, and black of the slates and clays. It has been dubbed "clay +metal" and "silver made from clay;" also when mixed with any +considerable quantity of carbon becoming a grayish or bluish black "alum +slate." + +This metal in color is white and next in luster to silver. It has never +been found in a pure state, but is known to exist in combination with +nearly two hundred different minerals. Corundum and pure emery are ores +that are very rich in aluminum, containing about fifty-four per cent. +The specific gravity is but two and one-half times that of water; it is +lighter than glass or as light as chalk, being only one-third the weight +of iron and one-fourth the weight of silver; it is as malleable as gold, +tenacious as iron, and harder than steel, being next the diamond. Thus +it is capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. Its +variety of transformations is something wonderful. Meeting iron, or even +iron at its best in the form of steel, in the same field, it easily +vanquishes it at every point. It melts at 1,300 degrees F., or at least +600 degrees below the melting point of iron, and it neither oxidizes in +the atmosphere nor tarnishes in contact with gases. The enumeration of +the properties of aluminum is as enchanting as the scenes of a fairy +tale. + +Before proceeding further with this new wonder of science, which is +already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French chemist +Lavoisier, a very magician in the science, groping in the dark of the +last century, evolved the chemical theory of combustion--the existence +of a "highly respirable gas," oxygen, and the presence of metallic bases +in earths and alkalies. With the latter subject we have only to do at +the present moment. The metallic base was predicted, yet not identified. +The French Revolution swept this genius from the earth in 1794, and +darkness closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon the +metallic base of certain earths, but the reflection was so feeble that +the great secret was never revealed. Then a little later the Swedish +Berzelius and the Danish Oersted, confident in the prediction of +Lavoisier and of Davy, went in search of the mysterious stranger with +the aggressive electric current, but as yet to no purpose. It was +reserved to the distinguished German Wohler, in 1827, to complete the +work of the past fifty years of struggle and finally produce the minute +white globule of the pure metal from a mixture of the chloride of +aluminum and sodium, and at last the secret is revealed--the first step +was taken. It took twenty years of labor to revolve the mere discovery +into the production of the aluminum bead in 1846, and yet with this +first step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come. + +Returning again to France some time during the years between 1854 and +1858, and under the patronage of the Emperor Napoleon III., we behold +Deville at last forcing Nature to yield and give up this precious +quality as a manufactured product. Rose, of Berlin, and Gerhard, in +England, pressing hard upon the heels of the Frenchman, make permanent +the new product in the market at thirty-two dollars per pound. The +despair of three-quarters of a century of toilsome pursuit has been +broken, and the future of the metal has been established. + +The art of obtaining the metal since the period under consideration has +progressed steadily by one process after another, constantly increasing +in powers of productivity and reducing the cost. These arts are +intensely interesting to the student, but must be denied more than a +reference at this time. The price of the metal may be said to have come +within the reach of the manufacturing arts already. + +A present glance at the uses and possibilities of this wonderful metal, +its application and its varying quality, may not be out of place. Its +alloys are very numerous and always satisfactory; with iron, producing a +comparative rust proof; with copper, the beautiful golden bronze, and so +on, embracing the entire list of articles of usefulness as well as works +of art, jewelry, and scientific instruments. + +Its capacity to resist oxidation or rust fits it most eminently for all +household and cooking utensils, while its color transforms the dark +visaged, disagreeable array of pots, pans, and kitchen implements into +things of comparative beauty. As a metal it surpasses copper, brass, and +tin in being tasteless and odorless, besides being stronger than either. + +It has, as we have seen, bulk without weight, and consequently may be +available in construction of furniture and house fittings, as well in +the multitudinous requirements of architecture. The building art will +experience a rapid and radical change when this material enters as a +component material, for there will be possibilities such as are now +undreamed of in the erection of homes, public buildings, memorial +structures, etc. etc., for in this metal we have the strength, +durability, and the color to give all the variety that genius may +dictate. + +And when we take a still further survey of the vast field that is +opening before us, we find in the strength without size a most desirable +assistant in all the avenues of locomotion. It is the ideal metal for +railway traffic, for carriages and wagons. The steamships of the ocean +of equal size will double their cargo and increase the speed of the +present greyhounds of the sea, making six days from shore to shore seem +indeed an old time calculation and accomplishment. A thinner as well as +a lighter plate; a smaller as well as a stronger engine; a larger as +well as a less hazardous propeller; and a natural condition of +resistance to the action of the elements; will make travel by water a +forcible rival to the speed attained upon land, and bring all the +distant countries in contact with our civilization, to the profit of +all. This metal is destined to annihilate space even beyond the dream of +philosopher or poet. + +The tensile strength of this material is something equally wonderful, +when wire drawn reaches as high as 128,000 pounds, and under other +conditions reaches nearly if not quite 100,000 pounds to the square +inch. The requirements of the British and German governments in the best +wrought steel guns reach only a standard of 70,000 pounds to the square +inch. Bridges may be constructed that shall be lighter than wooden ones +and of greater strength than wrought steel and entirely free from +corrosion. The time is not distant when the modern wonder of the +Brooklyn span will seem a toy. + +It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube. + +The resistance to corrosion evidently fits this metal for railway +sleepers to take the place of the decaying wooden ties. In this metal +the sleeper may be made as soft and yielding as lead, while the rail may +be harder and tougher than steel, thus at once forming the necessary +cushion and the avoidance of jar and noise, at the same time +contributing to additional security in virtue of a stronger rail. + +In conductivity this metal is only exceeded by copper, having many times +that of iron. Thus in telegraphy there are renewed prospects in the +supplanting of the galvanized iron wire--lightness, strength, and +durability. When applied to the generation of steam, this material will +enable us to carry higher pressure at a reduced cost and increased +safety, as this will be accomplished by the thinner plate, the greater +conductivity of heat, and the better fiber. + +It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in the +mechanic art lies dormant--the size of the machine may be reduced, the +speed and the power increased, realizing the conception of two things +better done than one before. It is one of man's creative acts. + +From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, Paris, +asserts that 120,000 blows will exhaust the usefulness of the cushion of +the stamp machine, and this number of blows is given in a day; and that +when a cushion of aluminum bronze was substituted, it was unaffected +after months of use. + +If we have found a metal that possesses both tensile strength and +resistance to compression; malleability and ductility--the quality of +hardening, softening, and toughening by tempering; adaptability to +casting, rolling, or forging; susceptibility to luster and finish; of +complete homogeneous character and unusually resistant to destructive +agents--mankind will certainly leave the present accomplishments as +belonging to an effete past, and, as it were, start anew in a career of +greater prospects. + +This important material is to be found largely in nearly all the rocks, +or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal." +It is in every clay bank. It is particularly abundant in the coal +measures and is incidental to the shales or slates and clays that +underlie the coal. This under clay of the coal stratum was in all +probability the soil out of which grew the vegetation of the coal +deposits. It is a compound of aluminum and other matter, and, when mixed +with carbon and transformed by the processes of geologic action, it +becomes the shale rock which we know and which we discard as worthless +slate. And it is barely possible that we have been and are still carting +to the refuse pile an article more valuable than the so greatly lauded +coal waste or the merchantable coal itself. We have seen that the best +alumina ore contains only fifty-four per cent. of metal. + +The following prepared table has been furnished by the courtesy and +kindness of Mr. Alex. H. Sherred, of Scranton. + + ALUMINA. + +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 + +It will be seen that the black clay, shale, or slate, has a constituent +of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the +highest. Under every stratum of coal, and frequently mixed with it, are +these under deposits that are rich in the metal. When exposed to the +atmosphere, these shales yield a small deposit of alum. In the +manufacture of alum near Glasgow the shale and slate clay from the old +coal pits constitute the material used, and in France alum is +manufactured directly from the clay. + +Sufficient has been advanced to warrant the additional assertion that we +are here everywhere surrounded by this incomparable mineral, that it is +brought to the surface from its deposits deep in the earth by the +natural process in mining, and is only exceeded in quantity by the coal +itself. Taking a columnar section of our coal field, and computing the +thickness of each shale stratum, we have from twenty-five to sixty feet +in thickness of this metal-bearing substance, which averages over +twenty-five per cent. of the whole in quantity in metal. + +It is readily apparent that the only task now before us is the reduction +of the ore and the extraction of the metal. Can this be done? We answer, +it has been done. The egg has stood on end--the new world has been +sighted. All that now remains is to repeat the operation and extend the +process. Cheap aluminum will revolutionize industry, travel, comfort, +and indulgence, transforming the present into an even greater +civilization. Let us see. + +We have seen the discovery of the mere chemical existence of the metal, +we have stood by the birth of the first white globule or bead by Wohler, +in 1846, and witnesssed its introduction as a manufactured product in +1855, since which time, by the alteration and cheapening of one process +after another, it has fallen in price from thirty-two dollars per pound +in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent +labor at smelting have increased the quantity over a thousandfold and +reduced the cost upward of fifty per cent. + +All these processes involve the application of heat--a mere question of +the appliances. The electric currents of Berzelius and Oersted, the +crucible of Wohler, the closed furnaces and the hydrogen gas of the +French manufacturers and the Bessemer converter apparatus of Thompson, +all indicate one direction. This metal can be made to abandon its bed in +the earth and the rock at the will of man. During the past year, the +Messrs. Cowles, of Cleveland, by their electric smelting process, claim +to have made it possible to reduce the price of the metal to below four +dollars per pound; and there is now erecting at Lockport, New York, a +plant involving one million of capital for the purpose. + +Turning from the employment of the expensive reducing agents to the +simple and sole application of heat, we are unwilling to believe that we +do not here possess in eminence both the mineral and the medium of its +reduction. Whether the electric or the reverberatory or the converter +furnace system be employed, it is surely possible to produce the result. + +To enter into consideration of the details of these constructions would +involve more time than is permitted us on this occasion. They are very +interesting. We come again naturally to the limitless consideration of +powdered fuel, concerning which certain conclusions have been reached. +In the dissociation of water into its hydrogen and oxygen, with the +mingled carbon in a powdered state, we undoubtedly possess the elements +of combustion that are unexcelled on earth, a heat-producing combination +that in both activity and power leaves little to be desired this side of +the production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and furnaces. + +In the hope of stimulating thought to this infinite question of proper +fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope this +Board will not grudgingly devote to the subject, but which is impossible +at present. Do not forget that there is no single spot on the face of +the globe where nature has lavished more freely her choicest gifts. Let +us be active in the pursuit of the treasure and grateful for the +distinguished consideration. + + * * * * * + + + + +THE ORIGIN OF METEORITES. + + +On January 9, Professor Dewar delivered the sixth and last of his series +of lectures at the Royal Institution on "The Story of a Meteorite." [For +the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that +cosmic dust is found on Arctic snows and upon the bottom of the ocean; +all over the world, in fact, at some time or other, there has been a +large deposit of this meteoric dust, containing little round nodules +found also in meteorites. In Greenland some time ago numbers of what +were supposed to be meteoric stones were found; they contained iron, and +this iron, on being analyzed at Copenhagen, was found to be rich in +nickel. The Esquimaux once made knives from iron containing nickel; and +as any such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited the +basaltic coast in Greenland from which some of the supposed meteoric +stones had been brought, and in the middle of the rock large nodules +were found composed of iron and nickel; it, therefore, became evident +that the earth might produce masses not unlike such as come to us as +meteorites. The lecturer here exhibited a section of the Greenland rock +containing the iron, and nickel alloy, mixed with stony crystals, and +its resemblance to a section of a meteorite was obvious. It was 2½ times +denser than water, yet the whole earth is 5½ times denser than water, so +that if we could go deep enough, it is not improbable that our own globe +might be found to contain something like meteoric iron. He then called +attention to the following tables: + + _Elementary Substances found in Meteorites_. + + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. + +_Density of Meteorites_. + + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 + +_Interior of the Earth_ + + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 + +[Illustration] + +Twice a year, said Professor Dewar, what are called "falling stars" +maybe plentifully seen; the times of their appearance are in August and +November. Although thousands upon thousands of such small meteors have +passed through our atmosphere, there is no distinct record of one having +ever fallen to the earth during these annual displays. One was said to +have fallen recently at Naples, but on investigation it turned out to be +a myth. These annual meteors in the upper air are supposed to be only +small ones, and to be dissipated into dust and vapor at the time of +their sudden heating; so numerous are they that 40,000 have been counted +in one evening, and an exceptionally great display comes about once in +33¼ years. The inference from their periodicity is, that they are small +bodies moving round the sun in orbits of their own, and that whenever +the earth crosses their orbits, thereby getting into their path, a +splendid display of meteors results. A second display, a year later, +usually follows the exceptionally great display just mentioned, +consequently the train of meteors is of great length. Some of these +meteors just enter the atmosphere of the earth, then pass out again +forever, with their direction of motion altered by the influence of the +attraction of the earth. He here called attention to the accompanying +diagram of the orbits of meteors. + +The lecturer next invited attention to a hollow globe of linen or some +light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and +contained hidden within it the great electro-magnet, weighing 2 cwt., so +often used by Faraday in his experiments. He also exhibited a ball made +partly of thin iron; the globe represented the earth, for the purposes +of the experiment, and the ball a meteorite of somewhat large relative +size. The ball was then discharged at the globe from a little catapult; +sometimes the globe attracted the ball to its surface, and held it +there, sometimes it missed it, but altered its curve of motion through +the air. So was it, said the lecturer, with meteorites when they neared +the earth. Photographs from drawings, by Professor A. Herschel, of the +paths of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, is a +proof that their motions are parallel to each other; the parallel lines +seem to draw to a point at the greatest distance, for the same reason +that the rails of a straight line of railway seem to come from a distant +central point. The most interesting thing about the path of a company of +meteors is, that a comet is known to move in the same orbit; the comet +heads the procession, the meteors follow, and they are therefore, in all +probability, parts of comets, although everything about these difficult +matters cannot as yet be entirely explained; enough, however, is known +to give foundation for the assumption that meteorites and comets are not +very dissimilar. + +The light of a meteorite is not seen until it enters the atmosphere of +the earth, but falling meteorites can be vaporized by electricity, and +the light emitted by their constituents be then examined with the +spectroscope. The light of comets can be directly examined, and it +reveals the presence in those bodies of sodium, carbon, and a few other +well-known substances. He would put a piece of meteorite in the electric +arc to see what light it would give; he had never tried the experiment +before. The lights of the theater were then turned down, and the +discourse was continued in darkness; among the most prominent lines +visible in the spectrum of the meteorite, Professor Dewar specified +magnesium, sodium, and lithium. "Where do meteorites come from?" said +the lecturer. It might be, he continued, that they were portions of +exploded planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular hypothesis +that at some long past time our sun and all his planets existed but as a +volume of gas, which in contracting and cooling formed a hot volume of +rotating liquid, and that as this further contracted and cooled, the +planets, and moons, and planetary rings fell off from it and gradually +solidified, the sun being left as the solitary comparatively uncooled +portion of the original nebula. In partial illustration of this, he +caused a little globe of oil, suspended in an aqueous liquid of nearly +its own specific gravity, to rotate, and as it rotated it was seen, by +means of its magnified image upon the screen, to throw off from its +outer circumference rings and little globes. + + * * * * * + + + + +CANDELABRA CACTUS AND CALIFORNIA WOODPECKER. + +By C.F. HOLDER. + + +One of the most picturesque objects that meet the eye of the traveler +over the great plains of the southern portion of California and New +Mexico is the candelabra cactus. Systematically it belongs to the Cereus +family, in which the notable Night-blooming Cereus also is naturally +included. In tropical or semi-tropical countries these plants thrive, +and grow to enormous size. For example, the Cereus that bears those +great flowers, and blooms at night, exhaling powerful perfume, as we see +them in hothouses in our cold climate, are even in the semi-tropical +region of Key West, on the Florida Reef, seen to grow enormously in +length. + +[Illustration: THE CANDELABRA CACTUS--CEREUS GIGANTEUS.] + +We cultivated several species of the more interesting forms during a +residence on the reef. Our brick house, two stories in height, was +entirely covered on a broad gable end, the branches more than gaining +the top. There is a regular monthly growth, and this is indicated by a +joint between each two lengths. Should the stalk be allowed to grow +without support, it will continue growing without division, and exhibit +stalks five or six feet in length, when they droop, and fall upon the +ground. + +Where there is a convenient resting place on which it can spread out and +attach itself, the stalk throws out feelers and rootlets, which fasten +securely to the wall or brickwork; then, this being a normal growth, +there is a separation at intervals of about a foot. That is, the stalk +grows in one month about twelve inches, and if it has support, the +middle woody stalk continues to grow about an inch further, but has no +green, succulent portion, in fact, looks like a stem; then the other +monthly growth takes place, and ends with a stem, and so on +indefinitely. Our house was entirely covered by the stems of such a +plant, and the flowers were gorgeous in the extreme. The perfume, +however, was so potent that it became a nuisance. Such is the +Night-blooming Cereus in the warm climates, and similarly the Candelabra +Cereus grows in stalks, but architecturally erect, fluted like columns. +The flowers are large, and resemble those of the night-blooming variety. +Some columns remain single, and are amazingly artificial appearing; +others throw off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being clusters +of side shoots, the latter putting out from the trunk regularly, and +standing up parallel to each other. The enormous size these attain is +well shown in the picture. + +Whenever the great stalks of these cacti die, the succulent portion is +dried, and nothing is left but the woody fiber. They are hollow in +places, and easily penetrated. A species of woodpecker, _Melanerpes +formicivorus_, is found to have adopted the use of these dry stalks for +storing the winter's stock of provisions. There are several round +apertures seen on the stems in the pictures, which were pecked by this +bird. This species of woodpecker is about the size of our common robin +or migratory thrush, and has a bill stout and sharp. The holes are +pecked for the purpose of storing away acorns or other nuts; they are +just large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts are +so numerous, the stalk has the appearance of being studded with bullets. +This appearance is more pronounced in cases where the dead trunk of an +oak is used. There are some specimens of the latter now owned by the +American Museum of Natural History, which were originally sent to the +Centennial Exhibition at Philadelphia. They were placed in the +department contributed by the Pacific Railroad Company, and at that time +were regarded as some of the wonders of that newly explored region +through which the railroad was then penetrating. Some portions of the +surface of these logs are nearly entirely occupied by the holes with +acorns in them. The acorns are driven in very tightly in these examples; +much more so than in the cactus plants, as the oak is nearly round, and +the holes were pecked in solid though dead wood. One of the most +remarkable circumstances connected with this habit of the woodpecker is +the length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to make a +journey of sixty miles to accomplish the storing of one acorn. At first +it seemed strange that a bird should spend so much labor to place those +bits of food, and so far away. De Saussure, a Swiss naturalist, +published in the _Bibliotheque Universelle_, of Geneva, entertaining +accounts of the Mexican Colaptes, a variety of the familiar "high hold," +or golden winged woodpecker. They were seen to store acorns in the dead +stalks of the maguey (_Agave Americana_). Sumichrast, who accompanied +him to Central America, records the same facts. These travelers saw +great numbers of the woodpeckers in a region on the slope of a range of +volcanic mountains. There was little else of vegetation than the +_Agave_, whose barren, dead stems were studded with acorns placed there +by the woodpeckers. + +The maguey throws up a stalk about fifteen feet in height yearly, which, +after flowering, grows stalky and brittle, and remains an unsightly +thing. The interior is pithy, but after the death of the stalk the pith +contracts, and leaves the greater portion of the interior hollow, as we +have seen in the case of the cactus branches. How the birds found that +these stalks were hollow is a problem not yet solved, but, nevertheless, +they take the trouble to peck away at the hard bark, and once +penetrated, they commence to fill the interior; when one space is full, +the bird pecks a little higher up, and so continues. + +Dr. Heerman, of California, describes the California _Melanerpes_ as one +of the most abundant of the woodpeckers; and remarks that it catches +insects on the wing like a flycatcher. It is well determined that it +also eats the acorns that it takes so much pains to transport. + +[Illustration: FLOWER OF CEREUS GIGANTEUS.] + +It seems that these birds also store the pine trees, as well as the +oaks. It is not quite apparent why these birds exhibit such variation in +habits; they at times select the more solid trees, where the storing +cannot go on without each nut is separately set in a hole of its own. +There seems an instinct prompting them to do this work, though there may +not be any of the nuts touched again by the birds. Curiously enough, +there are many instances of the birds placing pebbles instead of nuts in +holes they have purposely pecked for them. Serious trouble has been +experienced by these pebbles suddenly coming in contact with the saw of +the mill through which the tree is running. The stone having been placed +in a living tree, as is often the case, its exterior had been lost to +sight during growth. + +Some doubt has been entertained about the purpose of the bird in storing +the nuts in this manner. De Saussure tells us he has witnessed the birds +eating the acorns after they had been placed in holes in trees, and +expresses his conviction that the insignificant grub which is only seen +in a small proportion of nuts is not the food they are in search of. + +C.W. Plass, Esq., of Napa City, California, had an interesting example +of the habits of the California _Melanerpes_ displayed in his own house. +The birds had deposited numbers of acorns in the gable end. A +considerable number of shells were found dropped underneath the eaves, +while some were found in place under the gable, and these were perfect, +having no grubs in them. + +The picture shows a very common scene in New Mexico. The columns, +straight and angular, are often sixty feet in height. It is called torch +cactus in some places. There are many varieties, and as many different +shapes. Some lie on the ground; others, attached to trunks of trees as +parasites, hang from branches like great serpents; but none is so +majestic as the species called systematically _Cereus giganteus_, most +appropriately. The species growing pretty abundantly on the island of +Key West is called candle cactus. It reaches some ten or twelve feet, +and is about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a pretty, +rather picturesque feature in the otherwise barren undergrowth of +shrubbery and small trees. Accompanied by a few flowering cocoa palms, +the view is not unpleasing. The fiber of these plants is utilized in +some coarse manufactures. The maguey, or Agave, is used in the +manufacture of fine roping. Manila hemp is made from a species. The +species whose dried stalks are used by the woodpeckers for their winter +storage was cultivated at Key West, Florida, during several years before +1858. Extensive fields of the Agave stood unappropriated at that period. +Considerable funds were dissipated on this venture. Extensive works were +established, and much confidence was entertained that the scheme would +prove a paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their long +stalks, stand now, increasing every year, until a portion of the island +is overrun with them. + + +CEREUS GIGANTEUS. + +This wonderful cactus, its colossal proportions, and weird, yet grand, +appearance in the rocky regions of Mexico and California, where it is +found in abundance, have been made known to us only through books of +travel, no large plants of it having as yet appeared in cultivation in +this country. It is questionable if ever the natural desire to see such +a vegetable curiosity represented by a large specimen in gardens like +Kew can be realized, owing to the difficulty of importing large stems in +a living condition; and even if successfully brought here, they survive +only a very short time. To grow young plants to a large size seems +equally beyond our power, as plants 6 inches high and carefully managed +are quite ten years old. When young, the stem is globose, afterward +becoming club-shaped or cylindrical. It flowers at the height of 12 +feet, but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of an +immense candelabrum, the base of the stem being as thick as a man's +body. The flower, of which a figure is given here, is about 5 inches +long and wide, the petals cream colored, the sepals greenish white. +Large clusters of flowers are developed together near the top of the +stem. A richly colored edible fruit like a large fig succeeds each +flower, and this is gathered by the natives and used as food under the +name of saguarro. A specimen of this cactus 3 feet high may be seen in +the succulent house at Kew.--_B., The Garden_. + + * * * * * + + + + +HOW PLANTS ARE REPRODUCED. + +[Footnote: Read at a meeting of the Chemists' Assistants' Association. +December 16, 1885.] + +By C.E. STUART, B.Sc. + + +In two previous papers read before this Association I have tried to +condense into as small a space as I could the processes of the nutrition +and of the growth of plants; in the present paper I want to set before +you the broad lines of the methods by which plants are reproduced. + +Although in the great trees of the conifers and the dicotyledons we have +apparently provision for growth for any number of years, or even +centuries, yet accident or decay, or one of the many ills that plants +are heirs to, will sooner or later put an end to the life of every +individual plant. + +Hence the most important act of a plant--not for itself perhaps, but for +its race--is the act by which it, as we say, "reproduces itself," that +is, the act which results in the giving of life to a second individual +of the same form, structure, and nature as the original plant. + +The methods by which it is secured that the second generation of the +plant shall be as well or even better fitted for the struggle of life +than the parent generation are so numerous and complicated that I cannot +in this paper do more than allude to them; they are most completely seen +in cross fertilization, and the adaptation of plant structures to that +end. + +What I want to point out at present are the principles and not so much +the details of reproduction, and I wish you to notice, as I proceed, +what is true not only of reproduction in plants but also of all +processes in nature, namely, the paucity of typical methods of attaining +the given end, and the multiplicity of special variation from those +typical methods. When we see the wonderfully varied forms of plant life, +and yet learn that, so to speak, each edifice is built with the same +kind of brick, called a cell, modified in form and function; when we see +the smallest and simplest equally with the largest and most complicated +plant increasing in size subject to the laws of growth by +intussusception and cell division, which are universal in the organic +world; we should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types. + +The first great generalization is into-- + +1. The vegetative type of reproduction, in which one or more ordinary +cells separate from the parent plant and become an independent plant; +and-- + +2. The special-cell type of reproduction, in which either one special +cell reproduces the plant, or two special cells by their union form the +origin of the new plant; these two modifications of the process are +known respectively as asexual and sexual. + +The third modification is a combination of the two others, namely, the +asexual special cell does not directly reproduce its parent form, but +gives rise to a structure in which sexual special cells are developed, +from whose coalescence springs again the likeness of the original plant. +This is termed alternation of generations. + +The sexual special cell is termed the _spore_. + +The sexual special cells are of one kind or of two kinds. + +Those which are of one kind may be termed, from their habit of yoking +themselves together, _zygoblasts_, or conjugating cells. + +Those which are of two kinds are, first, a generally aggressive and +motile fertilizing or so-called "male cell," called in its typical form +an _antherozoid_; and, second, a passive and motionless receptive or +so-called "female cell," called an _oosphere_. + +The product of the union of two zygoblasts is termed a _zygospore_. + +The product of the union of an antherozoid and an oosphere is termed an +_oospore_. + +In many cases the differentiation of the sexual cells does not proceed +so far as the formation of antherozoids or of distinct oospheres; these +cases I shall investigate with the others in detail presently. + +First, then, I will point out some of the modes of vegetative +reproduction. + +The commonest of these is cell division, as seen in unicellular plants, +such as protococcus, where the one cell which composes the plant simply +divides into two, and each newly formed cell is then a complete plant. + +The particular kind of cell division termed "budding" here deserves +mention. It is well seen in the yeast-plant, where the cell bulges at +one side, and this bulge becomes larger until it is nipped off from the +parent by contraction at the point of junction, and is then an +independent plant. + +Next, there is the process by which one plant becomes two by the dying +off of some connecting portion between two growing parts. + +Take, for instance, the case of the liverworts. In these there is a +thallus which starts from a central point and continually divides in a +forked or dichotomous manner. Now, if the central portion dies away, it +is obvious that there will be as many plants as there were forkings, and +the further the dying of the old end proceeds, the more young plants +will there be. + +Take again, among higher plants, the cases of suckers, runners, stolons, +offsets, etc. Here, by a process of growth but little removed from the +normal, portions of stems develop adventitious roots, and by the dying +away of the connecting links may become independent plants. + +Still another vegetative method of reproduction is that by bulbils or +gemmæ. + +A bulbil is a bud which becomes an independent plant before it commences +to elongate; it is generally fleshy, somewhat after the manner of a +bulb, hence its name. Examples occur in the axillary buds of _Lilium +bulbiferum_, in some _Alliums_, etc. + +The gemma is found most frequently in the liverworts and mosses, and is +highly characteristic of these plants, in which indeed vegetative +reproduction maybe said to reach its fullest and most varied extent. + +Gemmæ are here formed in a sort of flat cup, by division of superficial +cells of the thallus or of the stem, and they consist when mature of +flattened masses of cells, which lie loose in the cup, so that wind or +wet will carry them away on to soil or rock, when, either by direct +growth from apical cells, as with those of the liverworts, or with +previous emission of thread-like cells forming a "protonema," in the +case of the mosses, the young plant is produced from them. + +The lichens have a very peculiar method of gemmation. The lichen-thallus +is composed of chains or groups of round chlorophyl-containing cells, +called "gonidia," and masses of interwoven rows of elongated cells which +constitute the hyphæ. Under certain conditions single cells of the +gonidia become surrounded with a dense felt of hyphæ, these accumulate +in numbers below the surface of the thallus, until at last they break +out, are blown or washed away, and start germination by ordinary cell +division, and thus at once reproduce a fresh lichen-thallus. These +masses of cells are called soredia. + +Artificial budding and grafting do not enter into the scope of this +paper. + +As in the general growth and the vegetative reproduction of plants +cell-division is the chief method of cell formation, so in the +reproduction of plants by special cells the great feature is the part +played by cells which are produced not by the ordinary method of cell +division, but by one or the other processes of cell formation, namely, +free-cell formation or rejuvenescence. + +If we broaden somewhat the definition of rejuvenescence and free-cell +formation, and do not call the mother-cells of spores of mosses, higher +cryptogams, and also the mother-cells of pollen-grains, reproductive +cells, which strictly speaking they are not, but only producers of the +spores or pollen-grains, then we may say that _cell-division is confined +to vegetative processes, rejuvenescence and free-cell formation are +confined to reproductive processes_. + +Rejuvenescence may be defined as the rearrangement of the whole of the +protoplasm of a cell into a new cell, which becomes free from the +mother-cell, and may or may not secrete a cell-wall around it. + +If instead of the whole protoplasm of the cell arranging itself into one +mass, it divides into several, or if portions only of the protoplasm +become marked out into new cells, in each case accompanied by rounding +off and contraction, the new cells remaining free from one another, and +usually each secreting a cell wall, then this process, whose relation to +rejuvenescence is apparent, is called free-cell formation. + +The only case of purely vegetative cell-formation which takes place by +either of these processes is that of the formation of endosperm in +Selaginella and phanerogams, which is a process of free-cell formation. + +On the other hand, the universal contraction and rounding off of the +protoplasm, and the formation by either rejuvenescence or free-cell +formation, distinctly mark out the special or true reproductive cell. + +Examples of reproductive cells formed by rejuvenescence are: + +1. The swarm spores of many algæ, as Stigeoclonium (figured in Sachs' +"Botany"). Here the contents of the cell contract, rearrange themselves, +and burst the side of the containing wall, becoming free as a +reproductive cell. + +2. The zygoblasts of conjugating algæ, as in Spirogyra. Here the +contents of a cell contract and rearrange themselves only after contact +of the cell with one of another filament of the plant. This zygoblast +only becomes free after the process of conjugation, as described below. + +3. The oosphere of characeæ, mosses and liverworts, and vascular +cryptogams, where in special structures produced by cell-divisions there +arise single primordial cells, which divide into two portions, of which +the upper portion dissolves or becomes mucilaginous, while the lower +contracts and rearranges itself to form the oosphere. + +4. Spores of mosses and liverworts, of vascular cryptogams, and pollen +cells of phanerogams, which are the analogue of the spores. + +The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes a +wall of its own, and by the bursting or absorption of the wall of its +mother-cell becomes free. This is evidently a rejuvenescence. + +Examples of reproductive cells formed by free-cell formation are: + +1. The ascospores of fungi and algæ. + +2. The zoospores or mobile spores of many algæ and fungi. + +3. The germinal vesicles of phanerogams. + +The next portion of my subject is the study of the methods by which +these special cells reproduce the plant. + +1st. Asexual methods. + +1. Rejuvenescence gives rise to a swarm-spore or zoospore. The whole of +the protoplasm of a cell contracts, becomes rounded and rearranged, and +escapes into the water, in which the plant floats as a mass of +protoplasm, clear at one end and provided with cilia by which it is +enabled to move, until after a time it comes to rest, and after +secreting a wall forms a new plant by ordinary cell-division. Example: +Oedogonium. + +2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya. + +3. Free-cell formation forms the typical motionless spore of algæ and +fungi. For instance, in the asci of lichens there are formed from a +portion of the protoplasm four or more small ascospores, which secrete a +cell-wall and lie loose in the ascus. Occasionally these spores may +consist of two or more cells. They are set free by the rupture of the +ascus, and germinate by putting out through their walls one or more +filaments which branch and form the thallus of a new individual. Various +other spores formed in the same way are known as _tetraspores_, etc. + +4. Cell-division with rejuvenescence forms the spores of mosses and +higher cryptogams. + +To take the example of moss spores: + +Certain cells in the sporogonium of a moss are called mother-cells. The +protoplasm of each one of these becomes divided into four parts. Each of +these parts then secretes a cell-wall and becomes free as a spore by the +rupture or absorption of the wall of the mother-cell. The germination of +the spores I shall describe later. + +5. A process of budding which in the yeast plant and in mosses is merely +vegetatively reproductive, in fungi becomes truly reproductive, namely, +the buds are special cells arising from other special cells of the +hyphæ. + +For example, the so-called "gills" of the common mushroom have their +surface composed of the ends of the threads of cells constituting the +hyphæ. Some of these terminal cells push out a little finger of +protoplasm, which swells, thickens its wall, and becomes detached from +the mother-cell as a spore, here called specially a _basidiospore_. + +Also in the common gray mould of infusions and preserves, Penicillium, +by a process which is perhaps intermediate between budding and +cell-division, a cell at the end of a hypha constricts itself in several +places, and the constricted portions become separate as _conidiospores_. + +_Teleutospores, uredospores_, etc., are other names for spores similarly +formed. + +These conidiospores sometimes at once develop hyphæ, and sometimes, as +in the case of the potato fungus, they turn out their contents as a +swarm-spore, which actively moves about and penetrates the potato leaves +through the stomata before they come to rest and elongate into the +hyphal form. + +So far for asexual methods of reproduction. + +I shall now consider the sexual methods. + +The distinctive character of these methods is that the cell from which +the new individual is derived is incapable of producing by division or +otherwise that new individual without the aid of the protoplasm of +another cell. + +Why this should be we do not know; all that we can do is to guess that +there is some physical or chemical want which is only supplied through +the union of the two protoplasmic masses. The process is of benefit to +the species to which the individuals belong, since it gives it a greater +vigor and adaptability to varying conditions, for the separate +peculiarities of two individuals due to climatic or other conditions are +in the new generation combined in one individual. + +The simplest of the sexual processes is conjugation. Here the two +combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union. + +Conjugation occurs in algæ and fungi. A typical case is that of +Spirogyra. This is an alga with its cells in long filaments. Two +contiguous cells of two parallel filaments push each a little projection +from its cell-wall toward the other. When these meet, the protoplasm of +each of the two cells contracts, and assumes an elliptical form--it +undergoes rejuvenescence. Next an opening forms where the two cells are +in contact, and the contents of one cell pass over into the other, where +the two protoplasmic bodies coalesce, contract, and develop a cell-wall. +The zygospore thus formed germinates after a long period and forms a new +filament of cells. + +Another example of conjugation is that of Pandorina, an alga allied to +the well-known volvox. Here the conjugating cells swim free in water; +they have no cell-wall, and move actively by cilia. Two out of a number +approach, coalesce, contract, and secrete a cell-wall. After a long +period of rest, this zygospore allows the whole of its contents to +escape as a swarm-spore, which after a time secretes a gelatinous wall, +and by division reproduces the sixteen-celled family. + +We now come to fertilization, where the uniting cells are of two kinds. + +The simplest case is that of Vaucheria, an alga. Here the vegetative +filament puts out two protuberances, which become shut off from the body +of the filament by partitions. The protoplasm in one of these +protuberances arranges itself into a round mass--the oosphere or female +cell. The protoplasm of the other protuberance divides into many small +masses, furnished with cilia, the spermatozoids or male cells. Each +protuberance bursts, and some of the spermatozoids come in contact with +and are absorbed by the oosphere, which then secretes a cell-wall, and +after a time germinates. + +The most advanced type of fertilization is that of angiosperms. + +In them there are these differences from the above process: the contents +of the male cell, represented by the pollen, are not differentiated into +spermatozoids, and there is no actual contact between the contents of +the pollen tube and the germinal vesicle, but according to Strashurger, +there is a transference of the substance of the nucleus of the pollen +cell to that of the germinal vesicle by osmose. The coalescence of the +two nuclei within the substance of the germinal vesicle causes the +latter to secrete a wall, and to form a new plant by division, being +nourished the while by the mother plant, from whose tissues the young +embryo plant contained in the seed only becomes free when it is in an +advanced stage of differentiation. + +Perhaps the most remarkable cases of fertilization occur in the Florideæ +or red seaweeds, to which class the well-known Irish moss belongs. + +Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, some +other cell which is quite distinct from the primarily fertilized cell +carries on the reproductive process. + +If the allied group of the Coleochæteæ is considered together with the +Florideæ, we find a transition between the ordinary case of Coleochæte +and that of Dudresnaya. In Coleochæte, the male cell is a round +spermatozoid, and the female cell an oosphere contained in the base of a +cell which is elongated into an open and hair-like tube called the +trichogyne. The spermatozoid coalesces with the oosphere, which secretes +a wall, becomes surrounded with a covering of cells called a cystocarp, +which springs from cells below the trichogyne, and after the whole +structure falls from the parent plant, spores are developed from the +oospore, and from them arises a new generation. + +In Dudresnaya, on the other hand, the spermatozoid coalesces indeed with +the trichogyne, but this does not develop further. From below the +trichogyne, however, spring several branches, which run to the ends of +adjacent branches, with the apical cells of which they conjugate, and +the result of this conjugation is the development of a cystocarp similar +to that of Coleochæte. The remarkable point here is the way in which the +effect of the fertilizing process is carried from one cell to another +entirely distinct from it. + +Thus I have endeavored to sum up the processes of asexual and of sexual +reproduction. But it is a peculiar characteristic of most classes of +plants that the cycle of their existence is not complete until both +methods of reproduction have been called into play, and that the +structure produced by one method is entirely different from that +produced by the other method. + +Indeed, it is only in some algæ and fungi that the reproductive cells of +one generation produce a generation similar to the parent; in all other +plants a generation A produces are unlike generation B, which may either +go on to produce another generation, C, and then back to A, or it may go +on producing B's until one of these reproduces A, or again it may +directly reproduce; A. Thus we have the three types: + + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. + +The first case is not common, the usual number of generations being two +only; but a typical example of the occurrence of three generations is in +such fungi as _Puccinia Graminis_. Here the first generation grows on +barberry leaves, and produces a kind of spore called an _æcidium spore_. +These æcidium spores germinate only on a grass stem or leaf, and a +distinct generation is produced, having a particular kind of spore +called an _uredospore_. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation with +another kind of spore, called a _teleutospore_, is produced. + +The teleutospores only germinate on barberry leaves, and there reproduce +the original æcidium generation. + +Thus we have the series A.B.B.B ... BCA + +In this instance all the generations are asexual, but the most common +case is for the sexual and the asexual generations to alternate. I will +describe as examples the reproduction of a moss, a fern, and a +dicotyledon. + +In such a typical moss as Funaria, we have the following cycle of +developments: The sexual generation is a dioecious leafy structure, +having a central elongated axis, with leaves arranged regularly around +and along it. At the top of the axis in the male plant rise the +antheridia, surrounded by an envelope of modified leaves called the +perigonium. The antheridia are stalked sacs, with a single wall of +cells, and the spiral antherozoids arise by free-cell formation from the +cells of the interior. They are discharged by the bursting of the +antheridium, together with a mucilage formed of the degraded walls of +their mother cells. + +In the female plant there arise at the apex of the stem, surrounded by +an envelope of ordinary leaves, several archegonia. These are of the +ordinary type of those organs, namely, a broad lower portion, containing +a naked oosphere and a long narrow neck with a central canal leading to +the oosphere. Down this canal pass one or more antherozoids, which +become absorbed into the oosphere, and this then secretes a wall, and +from it grows the second or asexual generation. The peculiarity of this +asexual or spore-bearing plant is that it is parasitic on the sexual +plant; the two generations, although not organically connected, yet +remain in close contact, and the spore-bearing generation is at all +events for a time nourished by the leafy sexual generation. + +The spore-bearing generation consists of a long stalk, closely held +below by the cells of the base of the archegonium; this supports a +broadened portion which contains the spores, and the top is covered with +the remains of the neck of the archegonium forming the calyptra. + +The spores arise from special or mother-cells by a process of division, +or it may be even termed free-cell formation, the protoplasm of each +mother-cell dividing into four parts, each of which contracts, secretes +a wall, and thus by rejuvenescence becomes a spore, and by the +absorption of the mother-cells the spores lie loose in the spore sac. +The spores are set free by the bursting of their chamber, and each +germinates, putting out a branched thread of cells called a protonema, +which may perhaps properly be termed a third generation in the cycle of +the plant; for it is only from buds developed on this protonema that the +leafy sexual plant arises. + +The characteristics, then, of the mosses are, that the sexual generation +is leafy, the one or two asexual generations are thalloid, and that the +spore-bearing generation is in parasitic connection with the sexual +generation. + +In the case of the fern, these conditions are very different. + +The sexual generation is a small green thalloid structure called a +prothallium, which bears antheridia and archegonia, each archegonium +having a neck-canal and oosphere, which is fertilized just as in the +moss. + +But the asexual generation derived from the oospore only for a short +while remains in connection with the prothallium, which, of course, +answers to the leafy portion of the moss. What is generally known as the +fern is this asexual generation, a great contrast to the small leafless +moss fruit or sporogonium as it is called, to which it is +morphologically equivalent. On the leaves of this generation arise the +sporangia which contain the spores. The spores are formed in a manner +very similar to those of the mosses, and are set free by rupture of the +sporangium. + +The spore produces the small green prothallium by cell-division in the +usual way, and this completes the cycle of fern life. + +The alternation of generations, which is perhaps most clear and typical +in the case of the fern, becomes less distinctly marked in the plants of +higher organization and type. + +Thus in the Rhizocarpæ there are two kinds of spores, _microspores_ and +_macrospores_, producing prothallia which bear respectively antheridia +and archegonia; in the Lycopodiaceæ, the two kinds of spores produce +very rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the endosperm, in +which archegonia or corpuscula are formed; and lastly, in typical +dicotyledons it is only lately that any trace of a prothallium from the +microspore or pollen cell has been discovered, while the macrospore or +embryo-sac produces only two or three prothallium cells, known as +antipodal cells, and two or three oospheres, known as germinal vesicles. + +This description of the analogies of the pollen and embryo-sac of +dicotyledons assumes that the general vegetative structure of this class +of plants is equivalent to the asexual generation of the higher +cryptogams. In describing their cycle of reproduction I will endeavor to +show grounds for this assumption. + +We start with the embryo as contained in the seed. This embryo is the +product of fertilization of a germinal vesicle by a pollen tube. Hence, +by analogy with the product of fertilization of rhizocarp's, ferns, and +mosses, it should develop into a spore bearing plant. It does develop +into a plant in which on certain modified leaves are produced masses of +tissue in which two kinds of special reproductive cells are formed. This +is precisely analogous to the case of gymnosperms, lycopods, etc., where +on leaf structures are formed macro and micro sporangia. + +To deal first with the microsporangium or pollen-sac. The pollen cells +are formed from mother cells by a process of cell division and +subsequent setting free of the daughter cells or pollen cells by +rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceæ, etc. The subsequent +behavior of the pollen cell, its division and its fertilization of the +germinal vesicle or oosphere, leave no doubt as to its analogy with the +microspore of vascular cryptogams. + +Secondly, the nucleus of the ovule corresponds with the macrosporangium +of Selaginella, through the connecting link of the conifers, where the +ovule is of similar origin and position to the macrosporangium of the +Lycopodiaceæ. But the formation of the macrospore or embryo-sac is +simpler than the corresponding process in cryptogams. It arises by a +simple enlargement of one cell of the nucleus instead of by the division +of one cell into four, each thus becoming a macrospore. At the top of +this macrospore or embryo-sac two or three germinal vesicles are formed +by free cell formation, and also two or three cells called antipodal +cells, since they travel to the other end of the embryo-sac; these +latter represent a rudimentary prothallium. This formation of germinal +vesicles and prothallium seems very different from the formation of +archegonia and prothallium in Selaginella, for instance; but the link +which connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed. + +Thus we see that the flowering plant is essentially the equivalent of +the asexual fern, and of the sporogonium of the moss, and the pollen +cell and the embryo-sac represent the two spores of the higher +cryptogams, and the pollen tube and the germinal vesicles and antipodal +cells are all that remain of the sexual generation, seen in the moss as +a leafy plant, and in the fern as a prothallium. Indeed, when a plant +has monoecious or dioecious flowers, the distinction between the asexual +and the sexual generation has practically been lost, and the +spore-bearing generation has become identified with the sexual +generation. + +Having now described the formation of the pollen and the germinal +vesicles, it only remains to show how they form the embryo. The pollen +cell forms two or three divisions, which are either permanent or soon +absorbed; this, as before stated, is the rudimentary male prothallium. +Then when it lies on the stigma it develops a long tube, which passes +down the style and through the micropyle of the ovule to the germinal +vesicles, one of which is fertilized by what is probably an osmotic +transference of nuclear matter. The germinal vesicle now secretes a +wall, divides into two parts, and while the rest of the embyro-sac fills +with endosperm cells, it produces by cell division from the upper half a +short row of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or leafy +plant, and while in the fern each generation is an independent +structure, here in the dicotyledon, on the other hand, the asexual +generation or embryo is again for a time nourished in the interior of +the embryo-sac representing the sexual generation, and this again +derives its nourishment from the previous asexual generation, so that as +in the moss, there is again a partial parasitism of one generation on +the other. + +To sum up the methods of plant reproduction: They resolve themselves +into two classes. + +1st. Purely vegetative. + +2d. Truly reproductive by special cells. + +In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive methods. + +1st. Reproduction from an asexual spore. + +2d. Reproduction from an oospore formed by the combination of two sexual +cells. + +In the vast majority of plant species these two types are used by the +individuals alternately. + +The extraordinary similarity of the reproductive process, as shown in +the examples I have given, Achlya, Spirogyra, and Vaucheria among algæ, +the moss, the fern, and the flowering plant, a similarity which becomes +the more marked the more the details of each case and of the cases of +plants which form links between these great classes are studied, points +to a community of origin of all plants in some few or one primeval +ancestor. And to this inference the study of plant structure and +morphology, together with the evidence of palæobotany among other +circumstances, lends confirmatory evidence, and all modern discoveries, +as for instance that of the rudimentary prothallium formed by the pollen +of angiosperms, tend to the smoothing of the path by which the descent +of the higher plants from simpler types will, as I think, be eventually +shown. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +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. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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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, Vol. XXI., No. 531, March 6, 1886 + +Author: Various + +Release Date: February 29, 2004 [EBook #11383] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPP. 531 *** + + + + +Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland, +Charles Franks and the DP Team + + + + + + +</pre> + +<p class="ctr"><a href="./illustrations/1a.png"><img src= +"./illustrations/1a_th.jpg" alt=""></a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 531</h1> + +<h2>NEW YORK, MARCH 6, 1886</h2> + +<h4>Scientific American Supplement. Vol. XXI, No. 531.</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 AND METALLURGY.--Annatto.-Analyses of +the same.--By WM. LAWSON</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#2">Aluminum.--By J.A. PRICE.--Iron the basis of +civilization.-- Aluminum the metal of the future.--Discovery of +aluminum.--Art of obtaining the metal.--Uses and +possibilities</a></td> +</tr> + +<tr> +<td valign="top">II.</td> +<td><a href="#3">ENGINEERING AND MECHANICS.--The Use of Iron in +Fortification. --Armor-plated casements.--The Schumann-Gruson +chilled iron cupola.--Mougin's rolled iron cupola.--With full page +of engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#4">High Speed on the Ocean</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#5">Sibley College Lectures.--Principles and Methods +of Balancing Forces developed in Moving Bodies.--Momentum and +centrifugal force.--By CHAS.T. PORTER.--3 figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#6">Compressed Air Power Schemes.--By J. +STURGEON.--Several figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#7">The Berthon Collapsible Canoe.--2 +engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#8">The Fiftieth Anniversary of the Opening of the +First German Steam Railroad.--With full page engraving</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#9">Improved Coal Elevator.--With engraving</a></td> +</tr> + +<tr> +<td valign="top">III.</td> +<td><a href="#10">TECHNOLOGY.--Steel-making Ladles.--4 +figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#11">Water Gas.--The relative value of water gas and +other gases as Iron-reducing Agents.--By B.H. +THWAITE.--Experiments.--With tables and 1 figure</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#12">Japanese Rice Wine and Soja Sauce.--Method of +making</a></td> +</tr> + +<tr> +<td valign="top">IV.</td> +<td><a href="#13">ELECTRICITY, MICROSCOPY, ETC.-Apparatus for +demonstrating that Electricity develops only on the Surface of +Conductors.--1 figure</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#14">The Colson Telephone.--3 engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#15">The Meldometer.--An apparatus for determining the +melting points of minerals</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#16">Touch Transmission by Electricity in the +Education of Deaf Mutes.--By S. TEFFT WALKER.--With 1 +figure</a></td> +</tr> + +<tr> +<td valign="top">V.</td> +<td><a href="#17">HORTICULTURE.--Candelabra Cactus and the +California Woodpecker.--By C.F. HOLDER.--With 2 engravings</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#18">How Plants are reproduced.--By C.E. STUART.--A +paper read before the Chemists' Assistants' Association</a></td> +</tr> + +<tr> +<td valign="top">VI.</td> +<td><a href="#19">MISCELLANEOUS--The Origin of Meteorites.--With 1 +figure</a></td> +</tr> +</table> + +<hr> +<p><a name="3"></a></p> + +<h2>THE USE OF IRON IN FORTIFICATION.</h2> + +<p>Roumania is thinking of protecting a portion of the artillery of +the forts surrounding her capital by metallic cupolas. But, before +deciding upon the mode of constructing these formidable and costly +affairs, and before ordering them, she has desired to ascertain +their efficacy and the respective merits of the chilled iron armor +which was recently in fashion and of rolled iron, which looks as if +it were to be the fashion hereafter.</p> + +<p class="ctr"><a href="./illustrations/1b.png"><img src= +"./illustrations/1b_th.jpg" alt= +"FIG. 1.--MOUGIN'S ROLLED IRON TURRET."></a></p> + +<p class="ctr">FIG. 1.--MOUGIN'S ROLLED IRON TURRET.</p> + +<p>The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a +turret of rolled iron. Both of these recommend themselves by +various merits, and by remarkably ingenious arrangements, and it +only remains to be seen how they will behave under the fire of the +largest pieces of artillery.</p> + +<p class="ctr"><img src="./illustrations/1c.png" alt="FIG. 2."></p> + +<p class="ctr">FIG. 2.</p> + +<p>We are far in advance of the time when cannons with smooth bore +were obliged to approach to within a very short range of a scarp in +order to open a breach, and we are far beyond that first rifled +artillery which effected so great a revolution in tactics.</p> + +<p class="ctr"><img src="./illustrations/1d.png" alt="FIG. 3."></p> + +<p class="ctr">FIG. 3.</p> + +<p>To-day we station the batteries that are to tear open a rampart +at distances therefrom of from 1,000 to 2,000 yards, and the long, +6 inch cannon that arms them has for probable deviations, under a +charge of 20 pounds of powder, and at a distance of 1,000 yards, 28 +feet in range, 16 inches in direct fire and 8 inches in curved.</p> + +<p>The weight of the projectile is 88 pounds, and its remanent +velocity at the moment of impact is 1,295 feet. Under this enormous +live force, the masonry gradually crumbles, and carries along the +earth of the parapet, and opens a breach for the assaulting +columns.</p> + +<p class="ctr"><img src="./illustrations/1e.png" alt=""></p> + +<p class="ctr">FIG. 4--STATE OF A CUPOLA AFTER THE<br> +ACTION OF THIRTY-SEVEN 6 IN. PROJECTILES.</p> + +<p>In order to protect the masonry of the scarp, engineers first +lowered the cordon to the level of the covert-way. Under these +circumstances, the enemy, although he could no longer see it, +reached it by a curved or "plunging" shot. When, in fact, for a +given distance we load a gun with the heaviest charge that it will +stand, the trajectory, AMB (Fig. 2), is as depressed as possible, +and the angles, a and a', at the start and arrival are small, and +we have a direct shot. If we raise the chase of the piece, the +projectile will describe a curve in space which would be a perfect +parabola were it not for the resistance of the air, and the summit +of such curve will rise in proportion as the angle so increases. So +long as the falling angle, a, remains less than 45°, we shall +have a curved shot. When the angle exceeds this, the shot is called +"vertical." If we preserve the same charge, the parabolic curve in +rising will meet the horizontal plane at a greater distance off. +This is, as well known, the process employed for reaching more and +more distant objects.</p> + +<p class="ctr"><img src="./illustrations/1f.png" alt=""></p> + +<p class="ctr">Fig. 5.--STATE OF A CAST-IRON CUPOLA<br> +AFTER THE BREAKAGE OF A VOUSSOIR.</p> + +<p>The length of a gun depends upon the maximum charge burned in +it, since the combustion must be complete when the projectile +reaches the open air. It results from this that although guns of +great length are capable of throwing projectiles with small +charges, it is possible to use shorter pieces for this +purpose--such as howitzers for curved shots and mortars for +vertical ones. The curved shot finds one application in the opening +of breaches in scarp walls, despite the existence of a covering of +great thickness. If, from a point, a (Fig. 3), we wish to strike +the point, b, of a scarp, over the crest, c, of the covert-way, it +will suffice to pass a parabolic curve through these three +points--the unknown data of the problem, and the charge necessary, +being ascertained, for any given piece, from the artillery tables. +In such cases it is necessary to ascertain the velocity at the +impact, since the force of penetration depends upon the live force +(mv²) of the projectile, and the latter will not penetrate +masonry unless it have sufficient remanent velocity. Live force, +however, is not the sole factor that intervenes, for it is +indispensable to consider the angle at which the projectile strikes +the wall. Modern guns, such as the Krupp 6 inch and De Bange 6 and +8 inch, make a breach, the two former at a falling angle of +22°, and the latter at one of 30°. It is not easy to lower +the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass +of the glacis.</p> + +<p>The same guns are employed for dismounting the defender's +pieces, which he covers as much as possible behind the parapet. +Heavy howitzers destroy the <i>materiel</i>, while shrapnel, +falling nearly vertically, and bursting among the men, render all +operations impossible upon an open terre-plein.</p> + +<p class="ctr"><img src="./illustrations/1g.png" alt=""></p> + +<p class="ctr">FIG. 6.--STATE OF A CHILLED IRON CUPOLA<br> +BROKEN BY A 12 INCH BALL.</p> + +<p>The effect of 6 and 8 inch rifled mortars is remarkable. The +Germans have a 9 inch one that weighs 3,850 pounds, and the +projectile of which weighs 300. But French mortars in nowise cede +to those of their neighbors; Col. De Bange, for example, has +constructed a 10½ inch one of wonderful power and +accuracy.</p> + +<p>Seeing the destructive power of these modern engines of war, it +may well be asked how many pieces the defense will be able to +preserve intact for the last period of a siege--for the very moment +at which it has most need of a few guns to hold the assailants in +check and destroy the assaulting columns. Engineers have proposed +two methods of protecting these few indispensable pieces. The first +of these consists in placing each gun under a masonry vault, which +is covered with earth on all sides except the one that contains the +embrasure, this side being covered with armor plate.</p> + +<p>The second consists in placing one or two guns under a metallic +cupola, the embrasures in which are as small as possible. The +cannon, in a vertical aim, revolves around the center of an +aperture which may be of very small dimensions. As regards direct +aim, the carriages are absolutely fixed to the cupola, which itself +revolves around a vertical axis. These cupolas may be struck in +three different ways: (1) at right angles, by a direct shot, and +consequently with a full charge--very dangerous blows, that +necessitate a great thickness of the armor plate; (2) obliquely, +when the projectile, if the normal component of its real velocity +is not sufficient to make it penetrate, will be deflected without +doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy.</p> + +<p>General Brialmont says that the metal of the cupola should be +able to withstand both penetration and breakage; but these two +conditions unfortunately require opposite qualities. A metal of +sufficient ductility to withstand breakage is easily penetrated, +and, conversely, one that is hard and does not permit of +penetration does not resist shocks well. Up to the present, +casehardened iron (Gruson) has appeared to best satisfy the +contradictory conditions of the problem. Upon the tempered exterior +of this, projectiles of chilled iron and cast steel break upon +striking, absorbing a part of their live force for their own +breakage.</p> + +<p>In 1875 Commandant Mougin performed some experiments with a +chilled iron turret established after these plans. The thickness of +the metal normally to the blows was 23½ inches, and the +projectiles were of cast steel. The trial consisted in firing two +solid 12 in. navy projectiles, 46 cylindrical 6 in. ones, weighing +100 lb., and 129 solid, pointed ones, 12 in. in diameter. The 6 +inch projectiles were fired from a distance of 3,280 feet, with a +remanent velocity of 1,300 feet. The different phases of the +experiment are shown in Figs. 4, 5, and 6. The cupola was broken; +but it is to be remarked that a movable and well-covered one would +not have been placed under so disadvantageous circumstances as the +one under consideration, upon which it was easy to superpose the +blows. An endeavor was next made to substitute a tougher metal for +casehardened iron, and steel was naturally thought of. But hammered +steel broke likewise, and a mixed or compound metal was still less +successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was +rolled iron. Armor plate composed of this latter has been submitted +to several tests, which appear to show that a thickness of 18 +inches will serve as a sufficient barrier to the shots of any gun +that an enemy can conveniently bring into the field.</p> + +<p class="ctr"><img src="./illustrations/1h.png" alt=""></p> + +<p class="ctr">FIG. 7.--CASEMATE OF CHILLED IRON AFTER<br> +RECEIVING NINETY-SIX SHOTS.</p> + +<p><i>Armor Plated Casemates</i>.--Fig. 7 shows the state of a +chilled iron casemate after a vigorous firing. The system that we +are about to describe is much better, and is due to Commandant +Mougin.</p> + +<p class="ctr"><a href="./illustrations/1i.png"><img src= +"./illustrations/1i_th.jpg" alt= +"FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE."></a></p> + +<p class="ctr">FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.</p> + +<p>The gun is placed under a vault whose generatrices are at right +angles to the line of fire (Fig. 8), and which contains a niche +that traverses the parapet. This niche is of concrete, and its +walls in the vicinity of the embrasure are protected by thick iron +plate. The rectangular armor plate of rolled iron rests against an +elastic cushion of sand compactly rammed into an iron plate +caisson. The conical embrasure traverses this cushion by means of a +cast-steel piece firmly bolted to the caisson, and applied to the +armor through the intermedium of a leaden ring. Externally, the +cheeks of the embrasure and the merlons consist of blocks of +concrete held in caissons of strong iron plate. The surrounding +earthwork is of sand. For closing the embrasure, Commandant Mougin +provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected +by the sloping mass of concrete that covers the head of the +casemate. A windlass and chain give the disk the motion that brings +one of its apertures opposite the embrasure or that closes the +latter. When this portion of the disk has suffered too much from +the enemy's fire, a simple maneuver gives it a half revolution, and +the second aperture is then made use of.</p> + +<p><i>The Schumann-Gruson Chilled Iron Cupola</i>.--This cupola +(Fig. 9) is dome-shaped, and thus offers but little surface to +direct fire; but it can be struck by a vertical shot, and it may be +inquired whether its top can withstand the shock of projectiles +from a 10 inch rifled mortar. It is designed for two 6 inch guns +placed parallel. Its internal diameter is 19½ feet, and the +dome is 8 inches in thickness and has a radius of 16½ feet. +It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of +relatively small bulk--a bad feature as regards resistance to +shock. To obviate this difficulty, the inventor partitions it +internally in such a way as to leave only sufficient space to +maneuver the guns. The partitions consist of iron plate boxes +filled with concrete. The form of the dome has one inconvenience, +viz., the embrasure in it is necessarily very oblique, and offers +quite an elongated ellipse to blows, and the edges of the bevel +upon a portion of the circumference are not strong enough. In order +to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides +of the embrasure. The motion of the piece necessary to aim it +vertically is effected around this axis of rotation. The weight of +the gun is balanced by a system of counterpoises and the chains, l, +and the breech terminates in a hollow screw, f, and a nut, g, held +between two directing sectors, h. The cupola is revolved by simply +acting upon the rollers.</p> + +<p class="ctr"><img src="./illustrations/1j.png" alt= +"FIG. 9.--THE SCHUMANN-GRUSON CUPOLA."></p> + +<p class="ctr">FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.</p> + +<p><i>Mougin's Rolled Iron Cupola</i>.--The general form of this +cupola (Fig. 1) is that of a cylindrical turret. It is 12¾ +feet in diameter, and rises 3¼ feet above the top of the +glacis. It has an advantage over the one just described in +possessing more internal space, without having so large a diameter; +and, as the embrasures are at right angles with the sides, the +plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of +strong iron plate strengthened by angle irons. Vertical partitions +under the cheeks of the gun carriages serve as cross braces, and +are connected with each other upon the table of the hydraulic pivot +around which the entire affair revolves. This pivot terminates in a +plunger that enters a strong steel press-cylinder embedded in the +masonry of the lower concrete vault.</p> + +<p>The iron plate ring carries wheels and rollers, through the +intermedium of which the turret is revolved. The circular iron +track over which these move is independent of the outer armor.</p> + +<p>The whole is maneuvered through the action of one man upon the +piston of a very small hydraulic press. The guns are mounted upon +hydraulic carriages. The brake that limits the recoil consists of +two bronze pump chambers, a and b (Fig. 10). The former of these is +4 inches in diameter, and its piston is connected with the gun, +while the other is 8 inches in diameter, and its piston is +connected with two rows of 26 couples of Belleville springs, d. The +two cylinders communicate through a check valve.</p> + +<p>When the gun is in battery, the liquid fills the chamber of the +4 inch pump, while the piston of the 8 inch one is at the end of +its stroke. A recoil has the effect of driving in the 4 inch piston +and forcing the liquid into the other chamber, whose piston +compresses the springs. At the end of the recoil, the gunner has +only to act upon the valve by means of a hand-wheel in order to +bring the gun into battery as slowly as he desires, through the +action of the springs.</p> + +<p class="ctr"><img src="./illustrations/2a.png" alt=""></p> + +<p class="ctr">FIG. 10.--MOUGIN'S HYDRAULIC GUN<br> +CARRIAGE.</p> + +<p>For high aiming, the gun and the movable part of its carriage +are capable of revolving around a strong pin, c, so placed that the +axis of the piece always passes very near the center of the +embrasure, thus permitting of giving the latter minimum dimensions. +The chamber of the 8 inch pump is provided with projections that +slide between circular guides, and carries the strap of a small +hydraulic piston, p, that suffices to move the entire affair in a +vertical plane, the gun and movable carriage being balanced by a +counterpoise, q.</p> + +<p>The projectiles are hoisted to the breech of the gun by a +crane.</p> + +<p>Between the outer armor and turret sufficient space is left for +a man to enter, in order to make repairs when necessary.</p> + +<p>Each of the rolled iron plates of which the turret consists +weighs 19 tons. The cupolas that we have examined in this article +have been constructed on the hypothesis than an enemy will not be +able to bring into the field guns of much greater caliber than 6 +inches.--<i>Le Genie Civil</i>.</p> + +<hr> +<p><a name="4"></a></p> + +<h2>HIGH SPEED ON THE OCEAN.</h2> + +<p><i>To the Editor of the Scientific American</i>:</p> + +<p>Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN +of Jan. 2, 1886, in regard to high speed on the ocean.</p> + +<p>Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the +plane of their motion, but at an angle to it, the same principle +would, if applied to a steamship, increase its speed. But let us +look at the subject from another standpoint. The quadruped has to +support the weight of his body, and propel himself forward, with +the same force. If the force be applied perpendicularly, the body +is elevated, but not moved forward. If the force is applied +horizontally, the body moves forward, but soon falls to the ground, +because it is not supported. But when the force is applied at the +proper angle, the body is moved forward and at the same time +supported. Directly contrary to Capt. Giles' theory, the greater +the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and <i>vice versa</i>. +This may easily be seen by any one watching the motions of the +horse, hound, deer, rabbit, etc., when in rapid motion. The water +birds and animals, whose weight is supported by the water, do not +exert the propulsive force in a downward direction, but in a direct +line with the plane of their motion. The man who swims does not +increase his motion by kicking out at an angle, but by drawing the +feet together with the legs straight, thus using the water between +them as a double inclined plane, on which his feet and legs slide +and thus increase his motion. The weight of the steamship is +already supported by the water, and all that is required of the +propeller is to push her forward. If set so as to act in a direct +line with the plane of motion, it will use all its force to push +her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. +If placed at an angle of 45° with the plane of motion, half the +force will be used in raising the ship out of the water, and only +half will be left to push her forward.</p> + +<p>ENOS M. RICKER.</p> + +<p>Park Rapids, Minn., Jan. 23, 1886.</p> + +<hr> +<h2>SIBLEY COLLEGE LECTURES.</h2> + +<h3>BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING.</h3> + +<p><a name="5"></a></p> + +<h2>PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES.</h2> + +<h3>BY CHAS. T. PORTER.</h3> + +<h3>INTRODUCTION.</h3> + +<p>On appearing for the first time before this Association, which, +as I am informed, comprises the faculty and the entire body of +students of the Sibley College of Mechanical Engineering and the +Mechanic Arts, a reminiscence of the founder of this College +suggests itself to me, in the relation of which I beg first to be +indulged.</p> + +<p>In the years 1847-8-9 I lived in Rochester, N.Y., and formed a +slight acquaintance with Mr. Sibley, whose home was then, as it has +ever since been, in that city. Nearly twelve years afterward, in +the summer of 1861, which will be remembered as the first year of +our civil war, I met Mr. Sibley again. We happened to occupy a seat +together in a car from New York to Albany. He recollected me, and +we had a conversation which made a lasting impression on my memory. +I said we had a conversation. That reminds me of a story told by my +dear friend, of precious memory, Alexander L. Holley. One summer +Mr. Holley accompanied a party of artists on an excursion to Mt. +Katahdin, which, as you know, rises in almost solitary grandeur +amid the forests and lakes of Maine. He wrote, in his inimitably +happy style, an account of this excursion, which appeared some time +after in <i>Scribner's Monthly</i>, elegantly illustrated with +views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. +Katahdin. "That is," he explained, "Mr. Church painted, and I held +the umbrella."</p> + +<p>This describes the conversation which Mr. Sibley and I had. Mr. +Sibley talked, and I listened. He was a good talker, and I flatter +myself that I rather excel as a listener. On that occasion I did my +best, for I knew whom I was listening to. I was listening to the +man who combined bold and comprehensive grasp of thought, unerring +foresight and sagacity, and energy of action and power of +accomplishment, in a degree not surpassed, if it was equaled, among +men.</p> + +<p>Some years before, Mr. Sibley had created the Western Union +Telegraph Company. At that time telegraphy was in a very depressed +state. The country was to a considerable extent occupied by local +lines, chartered under various State laws, and operated without +concert. Four rival companies, organized under the Morse, the Bain, +the House, and the Hughes patents, competed for the business. +Telegraph stock was nearly valueless. Hiram Sibley, a man of the +people, a resident of an inland city, of only moderate fortune, +alone grasped the situation. He saw that the nature of the +business, and the demands of the country, alike required that a +single organization, in which all interests should be combined, +should cover the entire land with its network, by means of which +every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this +vividly, and realized it with the most intense earnestness of +conviction. With Mr. Sibley, to be convinced was to act; and so he +set about the task of carrying this vast scheme into execution. The +result is well known. By his immense energy, the magnetic power +with which he infused his own convictions into other minds, the +direct, practical way in which he set about the work, and his +indomitable perseverance, Mr. Sibley attained at last a phenomenal +success.</p> + +<p>But he was not then telling me anything about this. He was +telling me of the construction of the telegraph line to the Pacific +Coast. Here again Mr. Sibley had seen that which was hidden from +others. This case differed from the former one in two important +respects. Then Mr. Sibley had been dependent on the aid and +co-operation of many persons; and this he had been able to secure. +Now, he could not obtain help from a human being; but he had become +able to act independently of any assistance.</p> + +<p>He had made a careful study of the subject, in his thoroughly +practical way, and had become convinced that such a line was +feasible, and would be remunerative. At his instance a convention +of telegraph men met in the city of New York, to consider the +project. The feeling in this convention was extremely unfavorable +to it. A committee reported against it unanimously, on three +grounds--the country was destitute of timber, the line would be +destroyed by the Indians, and if constructed and maintained, it +would not pay expenses. Mr. Sibley found himself alone. An earnest +appeal which he made from the report of the committee was received +with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and +two thousand miles of its breadth by bands of savages, who of +course would destroy the line as soon as it was put up, and where +repairs would be difficult and useless, even if the other +objections to it were out of the way, struck the members of the +convention as so exquisitely ludicrous that it seemed as if they +would never be done laughing about it. If Mr. Sibley had advocated +a line to the moon, they would hardly have seen in it greater +evidence of lunacy. When he could be heard, he rose again and said: +"Gentlemen, you may laugh, but if I was not so old, I would build +the line myself." Upon this, of course, they laughed louder than +ever. As they laughed, he grew mad, and shouted: "Gentlemen, I will +bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon +it scouted the project as chimerical, and no capitalist would put a +dollar in it, Hiram Sibley built the line of telegraph to San +Francisco, risking in it all he had in the world. He set about the +work with his customary energy, all obstacles vanished, and the +line was completed in an incredibly short time. And from the day it +was opened, it has proved probably the most profitable line of +telegraph that has ever been constructed. There was the +practicability, and there was the demand and the business to be +done, and yet no living man could see it, or could be made to see +it, except Hiram Sibley. "And to-day," he said, with honest pride, +"to-day in New York, men to whom I went almost on my knees for help +in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one."</p> + +<p>"But how about the Indians?" I asked. "Why," he replied, "we +never had any trouble from the Indians. I knew we wouldn't have. +Men who supposed I was such a fool as to go about this undertaking +before that was all settled didn't know me. No Indian ever harmed +that line. The Indians are the best friends we have got. You see, +we taught the Indians the Great Spirit was in that line; and what +was more, we proved it to them. It was, by all odds, the greatest +medicine they ever saw. They fairly worshiped it. No Indian ever +dared to do it harm."</p> + +<p>"But," he added, "there was one thing I didn't count on. The +border ruffians in Missouri are as bad as anybody ever feared the +Indians might be. They have given us so much trouble that we are +now building a line around that State, through Iowa and Nebraska. +We are obliged to do it."</p> + +<p>This opened another phase of the subject. The telegraph line to +the Pacific had a value beyond that which could be expressed in +money. It was perhaps the strongest of all the ties which bound +California so securely to the Union, in the dark days of its +struggle for existence. The secession element in Missouri +recognized the importance of the line in this respect, and were +persistent in their efforts to destroy it. We have seen by what +means their purpose was thwarted.</p> + +<p>I have always felt that, among the countless evidences of the +ordering of Providence by which the war for the preservation of the +Union was signalized, not the least striking was the raising up of +this remarkable man, to accomplish alone, and in the very nick of +time, a work which at once became of such national importance.</p> + +<p>This is the man who has crowned his useful career, and shown +again his eminently practical character and wise foresight, by the +endowment of this College, which cannot fail to be a perennial +source of benefit to the country whose interests he has done so +much to promote, and which his remarkable sagacity and energy +contributed so much to preserve.</p> + +<p>We have an excellent rule, followed by all successful designers +of machinery, which is, to make provision for the extreme case, for +the most severe test to which, under normal conditions, and so far +as practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than +the extreme demand are not likely to give trouble. I shall apply +this principle in addressing you to-day. In what I have to say, I +shall speak directly to the youngest and least advanced minds among +my auditors. If I am successful in making an exposition of my +subject which shall be plain to them, then it is evident that I +need not concern myself about being understood by the higher class +men and the professors.</p> + +<p>The subject to which your attention is now invited is</p> + +<h3>THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN +MOVING BODIES.</h3> + +<p>This is a subject with which every one who expects to be +concerned with machinery, either as designer or constructor, ought +to be familiar. The principles which underlie it are very simple, +but in order to be of use, these need to be thoroughly understood. +If they have once been mastered, made familiar, incorporated into +your intellectual being, so as to be readily and naturally applied +to every case as it arises, then you occupy a high vantage ground. +In this particular, at least, you will not go about your work +uncertainly, trying first this method and then that one, or leaving +errors to be disclosed when too late to remedy them. On the +contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what +you intend.</p> + +<p>Moreover, when you read discussions on any branch of this +subject, you will not receive these into unprepared minds, just as +apt to admit error as truth, and possessing no test by which to +distinguish the one from the other; but you will be able to form +intelligent judgments with respect to them. You will discover at +once whether or not the writers are anchored to the sure holding +ground of sound principles.</p> + +<p>It is to be observed that I do not speak of balancing bodies, +but of balancing forces. Forces are the realities with which, as +mechanical engineers, you will have directly to deal, all through +your lives. The present discussion is limited also to those forces +which are developed in moving bodies, or by the motion of bodies. +This limitation excludes the force of gravity, which acts on all +bodies alike, whether at rest or in motion. It is, indeed, often +desirable to neutralize the effect of gravity on machinery. The +methods of doing this are, however, obvious, and I shall not +further refer to them.</p> + +<p>Two very different forces, or manifestations of force, are +developed by the motion of bodies. These are</p> + +<h3>MOMENTUM AND CENTRIFUGAL FORCE.</h3> + +<p>The first of these forces is exerted by every moving body, +whatever the nature of the path in which it is moving, and always +in the direction of its motion. The latter force is exerted only by +bodies whose path is a circle, or a curve of some form, about a +central body or point, to which it is held, and this force is +always at right angles with the direction of motion of the +body.</p> + +<p>Respecting momentum, I wish only to call your attention to a +single fact, which will become of importance in the course of our +discussion. Experiments on falling bodies, as well as all +experience, show that the velocity of every moving body is the +product of two factors, which must combine to produce it. Those +factors are force and distance. In order to impart motion to the +body, force must act through distance. These two factors may be +combined in any proportions whatever. The velocity imparted to the +body will vary as the square root of their product. Thus, in the +case of any given body,</p> + +<pre> + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. +</pre> + +<p>This table might be continued indefinitely. The product of the +force into the distance will always vary as the square of the final +velocity imparted. To arrest a given velocity, the same force, +acting through the same distance, or the same product of force into +distance, is required that was required to impart the velocity.</p> + +<p>The fundamental truth which I now wish to impress upon your +minds is that in order to impart velocity to a body, to develop the +energy which is possessed by a body in motion, force must act +through distance. Distance is a factor as essential as force. +Infinite force could not impart to a body the least velocity, could +not develop the least energy, without acting through distance.</p> + +<p>This exposition of the nature of momentum is sufficient for my +present purpose. I shall have occasion to apply it later on, and to +describe the methods of balancing this force, in those cases in +which it becomes necessary or desirable to do so. At present I will +proceed to consider the second of the forces, or manifestations of +force, which are developed in moving bodies--<i>centrifugal +force</i>.</p> + +<p>This force presents its claims to attention in all bodies which +revolve about fixed centers, and sometimes these claims are +presented with a good deal of urgency. At the same time, there is +probably no subject, about which the ideas of men generally are +more vague and confused. This confusion is directly due to the +vague manner in which the subject of centrifugal force is treated, +even by our best writers. As would then naturally be expected, the +definitions of it commonly found in our handbooks are generally +indefinite, or misleading, or even absolutely untrue.</p> + +<p>Before we can intelligently consider the principles and methods +of balancing this force, we must get a correct conception of the +nature of the force itself. What, then, is centrifugal force? It is +an extremely simple thing; a very ordinary amount of mechanical +intelligence is sufficient to enable one to form a correct and +clear idea of it. This fact renders it all the more surprising that +such inaccurate and confused language should be employed in its +definition. Respecting writers, also, who use language with +precision, and who are profound masters of this subject, it must be +said that, if it had been their purpose to shroud centrifugal force +in mystery, they could hardly have accomplished this purpose more +effectually than they have done, to minds by whom it was not +already well understood.</p> + +<p>Let us suppose a body to be moving in a circular path, around a +center to which it is firmly held; and let us, moreover, suppose +the impelling force, by which the body was put in motion, to have +ceased; and, also, that the body encounters no resistance to its +motion. It is then, by our supposition, moving in its circular path +with a uniform velocity, neither accelerated nor retarded. Under +these conditions, what is the force which is being exerted on this +body? Clearly, there is only one such force, and that is, the force +which holds it to the center, and compels it, in its uniform +motion, to maintain a fixed distance from this center. This is what +is termed centripetal force. It is obvious, that the centripetal +force, which holds this revolving body <i>to</i> the center, is the +only force which is being exerted upon it.</p> + +<p>Where, then, is the centrifugal force? Why, the fact is, there +is not any such thing. In the dynamical sense of the term "force," +the sense in which this term is always understood in ordinary +speech, as something tending to produce motion, and the direction +of which determines the direction in which motion of a body must +take place, there is, I repeat, no such thing as centrifugal +force.</p> + +<p>There is, however, another sense in which the term "force" is +employed, which, in distinction from the above, is termed a +statical sense. This "statical force" is the force by the exertion +of which a body keeps still. It is the force of inertia--the +resistance which all matter opposes to a dynamical force exerted to +put it in motion. This is the sense in which the term "force" is +employed in the expression "centrifugal force." Is that all? you +ask. Yes; that is all.</p> + +<p>I must explain to you how it is that a revolving body exerts +this resistance to being put in motion, when all the while it +<i>is</i> in motion, with, according to our above supposition, a +uniform velocity. The first law of motion, so far as we now have +occasion to employ it, is that a body, when put in motion, moves in +a straight line. This a moving body always does, unless it is acted +on by some force, other than its impelling force, which deflects +it, or turns it aside, from its direct line of motion. A familiar +example of this deflecting force is afforded by the force of +gravity, as it acts on a projectile. The projectile, discharged at +any angle of elevation, would move on in a straight line forever, +but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made +to fall, by the attraction of the earth; and so instead of a +straight line it describes a curve, known as the trajectory.</p> + +<p>Now a revolving body, also, has the same tendency to move in a +straight line. It would do so, if it were not continually deflected +from this line. Another force is constantly exerted upon it, +compelling it, at every successive point of its path, to leave the +direct line of motion, and move on a line which is everywhere +equally distant from the center to which it is held. If at any +point the revolving body could get free, and sometimes it does get +free, it would move straight on, in a line tangent to the circle at +the point of its liberation. But if it cannot get free, it is +compelled to leave each new tangential direction, as soon as it has +taken it.</p> + +<p>This is illustrated in the above figure. The body, A, is +supposed to be revolving in the direction indicated by the arrow, +in the circle, A B F G, around the center, O, to which it is held +by the cord, O A. At the point, A, it is moving in the tangential +direction, A D. It would continue to move in this direction, did +not the cord, O A, compel it to move in the arc, A C. Should this +cord break at the point, A, the body would move; straight on toward +D, with whatever velocity it had.</p> + +<p>You perceive now what centrifugal force is. This body is moving +in the direction, A D. The centripetal force, exerted through the +cord, O A, pulls it aside from this direction of motion. The body +resists this deflection, and this resistance is its centrifugal +force.</p> + +<p class="ctr"><img src="./illustrations/3a.png" alt="Fig. 1"></p> + +<p class="ctr">Fig. 1</p> + +<p>Centrifugal force is, then, properly defined to be the +disposition of a revolving body to move in a straight line, and the +resistance which such a body opposes to being drawn aside from a +straight line of motion. The force which draws the revolving body +continually to the center, or the deflecting force, is called the +centripetal force, and, aside from the impelling and retarding +forces which act in the direction of its motion, the centripetal +force is, dynamically speaking, the only force which is exerted on +the body.</p> + +<p>It is true, the resistance of the body furnishes the measure of +the centripetal force. That is, the centripetal force must be +exerted in a degree sufficient to overcome this resistance, if the +body is to move in the circular path. In this respect, however, +this case does not differ from every other case of the exertion of +force. Force is always exerted to overcome resistance: otherwise it +could not be exerted. And the resistance always furnishes the exact +measure of the force. I wish to make it entirely clear, that in the +dynamical sense of the term "force," there is no such thing as +centrifugal force. The dynamical force, that which produces motion, +is the centripetal force, drawing the body continually from the +tangential direction, toward the center; and what is termed +centrifugal force is merely the resistance which the body opposes +to this deflection, <i>precisely like any other resistance to a +force</i>.</p> + +<p>The centripetal force is exerted on the radial line, as on the +line, A O, Fig. 1, at right angles with the direction in which the +body is moving; and draws it directly toward the center. It is, +therefore, necessary that the resistance to this force shall also +be exerted on the same line, in the opposite direction, or directly +from the center. But this resistance has not the least power or +tendency to produce motion in the direction in which it is exerted, +any more than any other resistance has.</p> + +<p>We have been supposing a body to be firmly held to the center, +so as to be compelled to revolve about it in a fixed path. But the +bond which holds it to the center may be elastic, and in that case, +if the centrifugal force is sufficient, the body will be drawn from +the center, stretching the elastic bond. It may be asked if this +does not show centrifugal force to be a force tending to produce +motion from the center. This question is answered by describing the +action which really takes place. The revolving body is now +imperfectly deflected. The bond is not strong enough to compel it +to leave its direct line of motion, and so it advances a certain +distance along this tangential line. This advance brings the body +into a larger circle, and by this enlargement of the circle, +assuming the rate of revolution to be maintained, its centrifugal +force is proportionately increased. The deflecting power exerted by +the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct +path; and when the limit of its elasticity is reached, the +deflecting bond will be broken. If, however, the strength of the +deflecting bond is increased by its elongation in a more rapid +ratio than the centrifugal force is increased by the enlargement of +the circle, then a point will be reached in which the centripetal +force will be sufficient to compel the body to move again in the +circular path.</p> + +<p>Sometimes the centripetal force is weak, and opportunity is +afforded to observe this action, and see its character exhibited. A +common example of weak centripetal force is the adhesion of water +to the face of a revolving grindstone. Here we see the deflecting +force to become insufficient to compel the drops of water longer to +leave their direct paths, and so these do not longer leave their +direct paths, but move on in those paths, with the velocity they +have at the instant of leaving the stone, flying off on tangential +lines.</p> + +<p>If, however, a fluid be poured on the side of the revolving +wheel near the axis, it will move out to the rim on radial lines, +as may be observed on car wheels universally. The radial lines of +black oil on these wheels look very much as if centrifugal force +actually did produce motion, or had at least a very decided +tendency to produce motion, in the radial direction. This +interesting action calls for explanation. In this action the oil +moves outward gradually, or by inconceivably minute steps. Its +adhesion being overcome in the least possible degree, it moves in +the same degree tangentially. In so doing it comes in contact with +a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it +had overcome the adhesion. Motion in the radial direction is the +result of these two actions, namely, leaving the first point of +contact tangentially and receiving an acceleration of its motion, +so that this shall be equal to that of the second point of contact. +When we think about the matter a little closely, we see that at the +rim of the wheel the oil has perhaps ten times the velocity of +revolution which it had on leaving the journal, and that the +mystery to be explained really is, How did it get that velocity, +moving out on a radial line? Why was it not left behind at the very +first? Solely by reason of its forward tangential motion. That is +the answer.</p> + +<p>When writers who understand the subject talk about the +centripetal and centrifugal forces being different names for the +same force, and about equal action and reaction, and employ other +confusing expressions, just remember that all they really mean is +to express the universal relation between force and resistance. The +expression "centrifugal force" is itself so misleading, that it +becomes especially important that the real nature of this so-called +force, or the sense in which the term "force" is used in this +expression, should be fully explained.[1] This force is now seen to +be merely the tendency of a revolving body to move in a straight +line, and the resistance which it opposes to being drawn aside from +that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see.</p> + +<p>[Footnote 1: I was led to study this subject in looking to see +what had become of my first permanent investment, a small venture, +made about thirty-five years ago, in the "Sawyer and Gwynne static +pressure engine." This was the high-sounding name of the Keely +motor of that day, an imposition made possible by the confused +ideas prevalent on this very subject of centrifugal force.]</p> + +<p>FIRST.--I have called your attention to the fact that the +direction in which the revolving body is deflected from the +tangential line of motion is toward the center, on the radial line, +which forms a right angle with the tangent on which the body is +moving. The first question that presents itself is this: What is +the measure or amount of this deflection? The answer is, this +measure or amount is the versed sine of the angle through which the +body moves.</p> + +<p>Now, I suspect that some of you--some of those whom I am +directly addressing--may not know what the versed sine of an angle +is; so I must tell you. We will refer again to Fig. 1. In this +figure, O A is one radius of the circle in which the body A is +revolving. O C is another radius of this circle. These two radii +include between them the angle A O C. This angle is subtended by +the arc A C. If from the point O we let fall the line C E +perpendicular to the radius O A, this line will divide the radius O +A into two parts, O E and E A. Now we have the three interior +lines, or the three lines within the circle, which are fundamental +in trigonometry. C E is the sine, O E is the cosine, and E A is the +versed sine of the angle A O C. Respecting these three lines there +are many things to be observed. I will call your attention to the +following only:</p> + +<p><i>First</i>.--Their length is always less than the radius. The +radius is expressed by 1, or unity. So, these lines being less than +unity, their length is always expressed by decimals, which mean +equal to such a proportion of the radius.</p> + +<p><i>Second</i>.--The cosine and the versed sine are together +equal to the radius, so that the versed sine is always 1, less the +cosine.</p> + +<p><i>Third</i>.--If I diminish the angle A O C, by moving the +radius O C toward O A, the sine C E diminishes rapidly, and the +versed sine E A also diminishes, but more slowly, while the cosine +O E increases. This you will see represented in the smaller angles +shown in Fig. 2. If, finally, I make O C to coincide with O A, the +angle is obliterated, the sine and the versed sine have both +disappeared, and the cosine has become the radius.</p> + +<p><i>Fourth</i>.--If, on the contrary, I enlarge the angle A O C +by moving the radius O C toward O B, then the sine and the versed +sine both increase, and the cosine diminishes; and if, finally, I +make O C coincide with O B, then the cosine has disappeared, the +sine has become the radius O B, and the versed sine has become the +radius O A, thus forming the two sides inclosing the right angle A +O B. The study of this explanation will make you familiar with +these important lines. The sine and the cosine I shall have +occasion to employ in the latter part of my lecture. Now you know +what the versed sine of an angle is, and are able to observe in +Fig. 1 that the versed sine A E, of the angle A O C, represents in +a general way the distance that the body A will be deflected from +the tangent A D toward the center O while describing the arc A +C.</p> + +<p>The same law of deflection is shown, in smaller angles, in Fig. +2. In this figure, also, you observe in each of the angles A O B +and A O C that the deflection, from the tangential direction toward +the center, of a body moving in the arc A C is represented by the +versed sine of the angle. The tangent to the arc at A, from which +this deflection is measured, is omitted in this figure to avoid +confusion. It is shown sufficiently in Fig. 1. The angles in Fig. 2 +are still pretty large angles, being 12° and 24° +respectively. These large angles are used for convenience of +illustration; but it should be explained that this law does not +really hold in them, as is evident, because the arc is longer than +the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent +and arc coincide, and approximately so for exceedingly small +angles.</p> + +<p class="ctr"><img src="./illustrations/4a.png" alt="Fig. 2"></p> + +<p class="ctr">Fig. 2</p> + +<p>In reality, however, we have only to do with the case in which +the arc and the tangent do coincide, and in which the law that the +deflection is <i>equal to</i> the versed sine of the angle is +absolutely true. Here, in observing this most familiar thing, we +are, at a single step, taken to that which is utterly beyond our +comprehension. The angles we have to consider disappear, not only +from our sight, but even from our conception. As in every other +case when we push a physical investigation to its limit, so here +also, we find our power of thought transcended, and ourselves in +the presence of the infinite.</p> + +<p>We can discuss very small angles. We talk familiarly about the +angle which is subtended by 1" of arc. On Fig. 2, a short line is +drawn near to the radius O A'. The distance between O A' and this +short line is 1° of the arc A' B'. If we divide this distance +by 3,600, we get 1" of arc. The upper line of the Table of versed +sines given below is the versed sine of 1" of arc. It takes +1,296,000 of these angles to fill a circular space. These are a +great many angles, but they do not make a circle. They make a +polygon. If the radius of the circumscribed circle of this polygon +is 1,296,000 feet, which is nearly 213 geographical miles, each one +of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon +would be one-sixtieth of a geographical mile, or 101.46 feet. On +the orbit of the moon, at its mean distance from the earth, each of +these straight sides would be about 6,000 feet long.</p> + +<p>The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never +can reach the circle. When you swing a sling around your head, and +feel the uniform stress exerted on your hand through the cord, you +are made aware of an action which is entirely beyond the grasp of +our minds and the reach of our analysis.</p> + +<p>So always in practical operation that law is absolutely true +which we observe to be approximated to more and more nearly as we +consider smaller and smaller angles, that the versed sine of the +angle is the measure of its deflection from the straight line of +motion, or the measure of its fall toward the center, which takes +place at every point in the motion of a revolving body.</p> + +<p>Then, assuming the absolute truth of this law of deflection, we +find ourselves able to explain all the phenomena of centrifugal +force, and to compute its amount correctly in all cases.</p> + +<p>We have now advanced two steps. We have learned <i>the +direction</i> and <i>the measure</i> of the deflection, which a +revolving body continually suffers, and its resistance to which is +termed centrifugal force. The direction is toward the center, and +the measure is the versed sine of the angle.</p> + +<p>SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that +the amount of centrifugal force exerted by a revolving body varies +in four ways.</p> + +<p><i>First</i>.--Directly as the weight of the body.</p> + +<p><i>Second</i>.--In a given circle of revolution, as the square +of the speed or of the number of revolutions per minute; which two +expressions in this case mean the same thing.</p> + +<p><i>Third</i>.--With a given number of revolutions per minute, or +a given angular velocity[1] <i>directly</i> as the radius of the +circle; and</p> + +<p><i>Fourth</i>.--With a given actual velocity, or speed in feet +per minute, <i>inversely</i> as the radius of the circle.</p> + +<p>[Footnote 1: A revolving body is said to have the same angular +velocity, when it sweeps through equal angles in equal times. Its +actual velocity varies directly as the radius of the circle in +which it is revolving.]</p> + +<p>Of course there is a reason for these laws. You are not to learn +them by rote, or to accept them on any authority. You are taught +not to accept any rule or formula on authority, but to demand the +reason for it--to give yourselves no rest until you know the why +and wherefore, and comprehend these fully. This is education, not +cramming the mind with mere facts and rules to be memorized, but +drawing out the mental powers into activity, strengthening them by +use and exercise, and forming the habit, and at the same time +developing the power, of penetrating to the reason of things.</p> + +<p>In this way only, you will be able to meet the requirement of a +great educator, who said: "I do not care to be told what a young +man knows, but what he can <i>do</i>." I wish here to add my grain +to the weight of instruction which you receive, line upon line, +precept on precept, on this subject.</p> + +<p>The reason for these laws of centrifugal force is an extremely +simple one. The first law, that this force varies directly as the +weight of the body, is of course obvious. We need not refer to this +law any further. The second, third, and fourth laws merely express +the relative rates at which a revolving body is deflected from the +tangential direction of motion, in each of the three cases +described, and which cases embrace all possible conditions.</p> + +<p>These three rates of deflection are exhibited in Fig. 2. An +examination of this figure will give you a clear understanding of +them. Let us first suppose a body to be revolving about the point, +O, as a center, in a circle of which A B C is an arc, and with a +velocity which will carry it from A to B in one second of time. +Then in this time the body is deflected from the tangential +direction a distance equal to A D, the versed sine of the angle A O +B. Now let us suppose the velocity of this body to be doubled in +the same circle. In one second of time it moves from A to C, and is +deflected from the tangential direction of motion a distance equal +to A E, the versed sine of the angle, A O C. But A E is four times +A D. Here we see in a given circle of revolution the deflection +varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded.</p> + +<p>The following table will show, by comparison of the versed sines +of very small angles, the deflection in a given circle varying as +the square of the speed, when we penetrate to them, so nearly that +the error is not disclosed at the fifteenth place of decimals.</p> + +<pre> + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 +</pre> + +<p>You observe the deflection for 10" of arc is 100 times as great, +and for 100" of arc is 10,000 times as great as it is for 1" of +arc. So far as is shown by the 15th place of decimals, the versed +sine varies as the square of the angle; or, in a given circle, the +deflection, and so the centrifugal force, of a revolving body +varies as the square of the speed.</p> + +<p>The reason for the third law is equally apparent on inspection +of Fig. 2. It is obvious, that in the case of bodies making the +same number of revolutions in different circles, the deflection +must vary directly as the diameter of the circle, because for any +given angle the versed sine varies directly as the radius. Thus +radius O A' is twice radius O A, and so the versed sine of the arc +A' B' is twice the versed sine of the arc A B. Here, while the +angular velocity is the same, the actual velocity is doubled by +increase in the diameter of the circle, and so the deflection is +doubled. This exhibits the general law, that with a given angular +velocity the centrifugal force varies directly as the radius or +diameter of the circle.</p> + +<p>We come now to the reason for the fourth law, that, with a given +actual velocity, the centrifugal force varies <i>inversely</i> as +the diameter of the circle. If any of you ever revolved a weight at +the end of a cord with some velocity, and let the cord wind up, +suppose around your hand, without doing anything to accelerate the +motion, then, while the circle of revolution was growing smaller, +the actual velocity continuing nearly uniform, you have felt the +continually increasing stress, and have observed the increasing +angular velocity, the two obviously increasing in the same ratio. +That is the operation or action which the fourth law of centrifugal +force expresses. An examination of this same figure (Fig. 2) will +show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. +If we take the velocity A' B', double the velocity A B, and +transfer it to the smaller circle, we have the velocity A C. But +the deflection has been increasing as we have reduced the circle, +and now with one half the radius it is twice as great. It has +increased in the same ratio in which the angular velocity has +increased. Thus we see the simple and necessary nature of these +laws. They merely express the different rates of deflection of a +revolving body in these different cases.</p> + +<p>THIRD.--We have a coefficient of centrifugal force, by which we +are enabled to compute the amount of this resistance of a revolving +body to deflection from a direct line of motion in all cases. This +is that coefficient. The centrifugal force of a body making +<i>one</i> revolution per minute, in a circle of <i>one</i> foot +radius, is 0.000341 of the weight of the body.</p> + +<p>According to the above laws, we have only to multiply this +coefficient by the square of the number of revolutions made by the +body per minute, and this product by the radius of the circle in +feet, or in decimals of a foot, and we have the centrifugal force, +in terms of the weight of the body. Multiplying this by the weight +of the body in pounds, we have the centrifugal force in pounds.</p> + +<p>Of course you want to know how this coefficient has been found +out, and how you can be sure it is correct. I will tell you a very +simple way. There are also mathematical methods of ascertaining +this coefficient, which your professors, if you ask them, will let +you dig out for yourselves. The way I am going to tell you I found +out for myself, and that, I assure you, is the only way to learn +anything, so that it will stick; and the more trouble the search +gives you, the darker the way seems, and the greater the degree of +perseverance that is demanded, the more you will appreciate the +truth when you have found it, and the more complete and permanent +your possession of it will be.</p> + +<p>The explanation of this method may be a little more abstruse +than the explanations already given, but it is very simple and +elegant when you see it, and I fancy I can make it quite clear. I +shall have to preface it by the explanation of two simple laws. The +first of these is, that a body acted on by a constant force, so as +to have its motion uniformly accelerated, suppose in a straight +line, moves through distances which increase as the square of the +time that the accelerating force continues to be exerted.</p> + +<p>The necessary nature of this law, or rather the action of which +this law is the expression, is shown in Fig. 3.</p> + +<p class="ctr"><img src="./illustrations/4b.png" alt="Fig. 3"></p> + +<p class="ctr">Fig. 3</p> + +<p>Let the distances A B, B C, C D, and D E in this figure +represent four successive seconds of time. They may just as well be +conceived to represent any other equal units, however small. +Seconds are taken only for convenience. At the commencement of the +first second, let a body start from a state of rest at A, under the +action of a constant force, sufficient to move it in one second +through a distance of one foot. This distance also is taken only +for convenience. At the end of this second, the body will have +acquired a velocity of two feet per second. This is obvious +because, in order to move through one foot in this second, the body +must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. +Its motion increased uniformly. Therefore, at the termination of +the second its velocity must have reached two feet per second. Let +the triangle A B F represent this accelerated motion, and the +distance, of one foot, moved through during the first second, and +let the line B F represent the velocity of two feet per second, +acquired by the body at the end of it. Now let us imagine the +action of the accelerating force suddenly to cease, and the body to +move on merely with the velocity it has acquired. During the next +second it will move through two feet, as represented by the square +B F C I. But in fact, the action of the accelerating force does not +cease. This force continues to be exerted, and produces on the body +during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity +accelerated two additional feet per second, as represented by the +line I G. So in two seconds the body has moved through four feet. +We may follow the operation of this law as far as we choose. The +figure shows it during four seconds, or any other unit, of time, +and also for any unit of distance. Thus:</p> + +<pre> + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 +</pre> + +<p>So it is obvious that the distance moved through by a body whose +motion is uniformly accelerated increases as the square of the +time.</p> + +<p>But, you are asking, what has all this to do with a revolving +body? As soon as your minds can be started from a state of rest, +you will perceive that it has everything to do with a revolving +body. The centripetal force, which acts upon a revolving body to +draw it to the center, is a constant force, and under it the +revolving body must move or be deflected through distances which +increase as the squares of the times, just as any body must do when +acted on by a constant force. To prove that a revolving body obeys +this law, I have only to draw your attention to Fig. 2. Let the +equal arcs, A B and B C, in this figure represent now equal times, +as they will do in case of a body revolving in this circle with a +uniform velocity. The versed sines of the angles, A O B and A O C, +show that in the time, A C, the revolving body was deflected four +times as far from the tangent to the circle at A as it was in the +time, A B. So the deflection increased as the square of the time. +If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute +angles, absolutely so far as appears up to the fifteenth place of +decimals, as the square of the time.</p> + +<p>The standard from which all computations are made of the +distances passed through in given times by bodies whose motion is +uniformly accelerated, and from which the velocity acquired is +computed when the accelerating force is known, and the force is +found when the velocity acquired or the rate of acceleration is +known, is the velocity of a body falling to the earth. It has been +established by experiment, that in this latitude near the level of +the sea, a falling body in one second falls through a distance of +16.083 feet, and acquires a velocity of 32.166 feet per second; or, +rather, that it would do so if it did not meet the resistance of +the atmosphere. In the case of a falling body, its weight +furnishes, first, the inertia, or the resistance to motion, that +has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the +earth, or the force exerted to overcome its resistance. Here, as in +all possible cases, the force and the resistance are identical with +each other. The above is, therefore, found in this way to be the +rate at which the motion of any body will be accelerated when it is +acted on by a constant force equal to its weight, and encounters no +resistance.</p> + +<p>It follows that a revolving body, when moving uniformly in any +circle at a speed at which its deflection from a straight line of +motion is such that in one second this would amount to 16.083 feet, +requires the exertion of a centripetal force equal to its weight to +produce such deflection. The deflection varying as the square of +the time, in 0.01 of a second this deflection will be through a +distance of 0.0016083 of a foot.</p> + +<p>Now, at what speed must a body revolve, in a circle of one foot +radius, in order that in 0.01 of one second of time its deflection +from a tangential direction shall be 0.0016083 of a foot? This +decimal is the versed sine of the arc of 3°15', or of +3.25°. This angle is so small that the departure from the law +that the deflection is equal to the versed sine of the angle is too +slight to appear in our computation. Therefore, the arc of +3.25° is the arc of a circle of one foot radius through which a +body must revolve in 0.01 of a second of time, in order that the +centripetal force, and so the centrifugal force, shall be equal to +its weight. At this rate of revolution, in one second the body will +revolve through 325°, which is at the rate of 54.166 +revolutions per minute.</p> + +<p>Now there remains only one question more to be answered. If at +54.166 revolutions per minute the centrifugal force of a body is +equal to its weight, what will its centrifugal force be at one +revolution per minute in the same circle?</p> + +<p>To answer this question we have to employ the other extremely +simple law, which I said I must explain to you. It is this: The +acceleration and the force vary in a constant ratio with each +other. Thus, let force 1 produce acceleration 1, then force 1 +applied again will produce acceleration 1 again, or, in other +words, force 2 will produce acceleration 2, and so on. This being +so, and the amount of the deflection varying as the squares of the +speeds in the two cases, the centrifugal force of a body making one +revolution per minute in a circle of</p> + +<pre> + 1² + one foot radius will be ---------- = 0.000341 + 54.166² +</pre> + +<p>--the coefficient of centrifugal force.</p> + +<p>There is another mode of making this computation, which is +rather neater and more expeditious than the above. A body making +one revolution per minute in a circle of one foot radius will in +one second revolve through an arc of 6°. The versed sine of +this arc of 6° is 0.0054781046 of a foot. This is, therefore, +the distance through which a body revolving at this rate will be +deflected in one second. If it were acted on by a force equal to +its weight, it would be deflected through the distance of 16.083 +feet in the same time. What is the deflecting force actually +exerted upon it? Of</p> + +<pre> + 0.0054781046 +course, it is ------------. + 16.083 +</pre> + +<p>This division gives 0.000341 of its weight as such deflecting +force, the same as before.</p> + +<p>In taking the versed sine of 6°, a minute error is involved, +though not one large enough to change the last figure in the above +quotient. The law of uniform acceleration does not quite hold when +we come to an angle so large as 6°. If closer accuracy is +demanded, we can attain it, by taking the versed sine for 1°, +and multiplying this by 6². This gives as a product +0.0054829728, which is a little larger than the versed sine of +6°.</p> + +<p>I hope I have now kept my promise, and made it clear how the +coefficient of centrifugal force may be found in this simple +way.</p> + +<p>We have now learned several things about centrifugal force. Let +me recapitulate. We have learned:</p> + +<p>1st. The real nature of centrifugal force. That in the dynamical +sense of the term force, this is not a force at all: that it is not +capable of producing motion, that the force which is really exerted +on a revolving body is the centripetal force, and what we are +taught to call centrifugal force is nothing but the resistance +which a revolving body opposes to this force, precisely like any +other resistance.</p> + +<p>2d. The direction of the deflection, to which the centrifugal +force is the resistance, which is straight to the center.</p> + +<p>3d. The measure of this deflection; the versed sine of the +angle.</p> + +<p>4th. The reason of the laws of centrifugal force; that these +laws merely express the relative amount of the deflection, and so +the amount of the force required to produce the deflection, and of +the resistance of the revolving body to it, in all different +cases.</p> + +<p>5th. That the deflection of a revolving body presents a case +analogous to that of uniformly accelerated motion, under the action +of a constant force, similar to that which is presented by falling +bodies;[1] and finally,</p> + +<p>6th. How to find the coefficient, by which the amount of +centrifugal force exerted in any case may be computed.</p> + +<p>[Footnote 1: A body revolving with a uniform velocity in a +horizontal plane would present the only case of uniformly +accelerated motion that is possible to be realized under actual +conditions.]</p> + +<p>I now pass to some other features.</p> + +<p><i>First</i>.--You will observe that, relatively to the center, +a revolving body, at any point in its revolution, is at rest. That +is, it has no motion, either from or toward the center, except that +which is produced by the action of the centripetal force. It has, +therefore, this identity also with a falling body, that it starts +from a state of rest. This brings us to a far more comprehensive +definition of centrifugal force. This is the resistance which a +body opposes to being put in motion, at any velocity acquired in +any time, from a state of rest. Thus centrifugal force reveals to +us the measure of the inertia of matter. This inertia may be +demonstrated and exhibited by means of apparatus constructed on +this principle quite as accurately as it can be in any other +way.</p> + +<p><i>Second</i>.--You will also observe the fact, that motion must +be imparted to a body gradually. As distance, <i>through</i> which +force can act, is necessary to the impartation of velocity, so also +time, <i>during</i> which force can act, is necessary to the same +result. We do not know how motion from a state of rest begins, any +more than we know how a polygon becomes a circle. But we do know +that infinite force cannot impart absolutely instantaneous motion +to even the smallest body, or to a body capable of opposing the +least resistance. Time being an essential element or factor in the +impartation of velocity, if this factor be omitted, the least +resistance becomes infinite.</p> + +<p>We have a practical illustration of this truth in the explosion +of nitro-glycerine. If a small portion of this compound be exploded +on the surface of a granite bowlder, in the open air, the bowlder +will be rent into fragments. The explanation of this phenomenon +common among the laborers who are the most numerous witnesses of +it, which you have doubtless often heard, and which is accepted by +ignorant minds without further thought, is that the action of +nitro-glycerine is downward. We know that such an idea is +absurd.</p> + +<p>The explosive force must be exerted in all directions equally. +The real explanation is, that the explosive action of +nitro-glycerine is so nearly instantaneous, that the resistance of +the atmosphere is very nearly equal to that of the rock; at any +rate, is sufficient to cause the rock to be broken up. The rock +yields to the force very nearly as readily as the atmosphere +does.</p> + +<p><i>Third</i>. An interesting solution is presented here of what +is to many an astronomical puzzle. When I was younger than I am +now, I was greatly troubled to understand how it could be that if +the moon was always falling to the earth, as the astronomers +assured us it was, it should never reach it, nor have its falling +velocity accelerated. In popular treatises on astronomy, such for +example as that of Professor Newcomb, this is explained by a +diagram in which the tangential line is carried out as in Fig. 1, +and by showing that in falling from the point A to the earth as a +center, through distances increasing as the square of the time, the +moon, having the tangential velocity that it has, could never get +nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this +long tangential line has nothing to do with the motion of the moon, +and while we are compelled to assent to the demonstration, we want +something better. To my mind the better and more satisfactory +explanation is found in the fact that the moon is forever +commencing to fall, and is continually beginning to fall in a new +direction. A revolving body, as we have seen, never gets past that +point, which is entirely beyond our sight and our comprehension, of +beginning to fall, before the direction of its fall is changed. So, +under the attraction of the earth, the moon is forever leaving a +new tangential direction of motion at the same rate, without +acceleration.</p> + +<p>(<i>To be continued</i>.)</p> + +<hr> +<p><a name="6"></a></p> + +<h2>COMPRESSED AIR POWER SCHEMES.</h2> + +<h3>By J. STURGEON, Engineer of the Birmingham Compressed Air Power +Company.</h3> + +<p>In the article on "Gas, Air, and Water Power" in the +<i>Journal</i> for Dec. 8 last, you state that you await with some +curiosity my reply to certain points in reference to the compressed +air power schemes alluded to in that article. I now, therefore, +take the liberty of submitting to you the arguments on my side of +the question (which are substantially the same as those I am +submitting to Mr. Hewson, the Borough Engineer of Leeds). The +details and estimates for the Leeds scheme are not yet in a forward +enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system +in other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters +of detail. We have, however, recently succeeded in obtaining a +suitable place, and making arrangements for railway siding, water +supply, etc.; and we hope to be in a position to start early in the +present year.</p> + +<p>I inclose (1) a tabulated summary of the estimates for +Birmingham divided into stages of 3,000 gross indicated horse power +at a time; (2) a statement showing the cost to consumers in terms +of indicated horse power and in different modes, more or less +economical, of applying the air power in the consumers' engines; +(3) a tracing showing the method of laying the mains; (4) a tracing +showing the method of collecting the meter records at the central +station, by means of electric apparatus, and ascertaining the exact +amount of leakage. A short description of the two latter would be +as well.</p> + +<p>TABLE I.--<i>Showing the Progressive Development of the +Compressed Air System in stages of 3000 Indicated Horse Power +(gross) at a Time, and the Profits at each Stage</i></p> + +<pre> +_____________________________________________________________________________ +<br> +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- +<br> +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- +<br> +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| £12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | £25,595 | £25,595 | £25,595 | £25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | £82,455 | £124,714 | £167,094 | £209,455 | £251,795 | +----------------------------------------------------------------------------- +<br> +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| £6,405 | £7,855 | £9,305 | £10,955 | £12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | £12,080 | £18,508 | £24,944 | £31,589 | £38,096 | +----------------------------------------------------------------------------- +<br> +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- +</pre> + +<p>TABLE II.--<i>Cost of Air Power in Terms of Indicated Horse +Power</i>.</p> + +<p>Abbreviated column headings:</p> + +<p>Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. +H.P. per Hour.</p> + +<p>Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet.</p> + +<p>Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach +26 per Cent.</p> + +<p>Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic +Feet.</p> + +<p>Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach +26 per Cent.</p> + +<p>Abbreviated row headings:</p> + +<p>CASE 1.--Where air at 45 lbs. pressure is re-heated to 320° +Fahr., and expanded to atmospheric pressure.</p> + +<p>CASE 2.--Where air at 45 lbs. pressure is heated by boiling +water to 212° Fahr., and expanded to atmospheric pressure.</p> + +<p>CASE 3.--Where air is used expansively without re-heating, +whereby intensely cold air is exhausted, and may be used for ice +making, &c.</p> + +<p>CASE 4.--Where air is heated to 212° Fahr., and the terminal +pressure is 11.3 lbs. above that of the atmosphere</p> + +<p>CASE 5.--Where the air is used without heating, and cut off at +one-third of the stroke, as in ordinary slide-valve engines</p> + +<p>CASE 6.--Where the air is used without re-heating and without +expansion.</p> + +<pre> + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | £ s. d. | £ s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 0½| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 5½ | 9 10 5½| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 5½ | 9 1 10½| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ +</pre> + +<p>The great thing to guard against is leakage. If the pipes were +simply buried in the ground, it would be almost impossible to trace +leakage, or even to know of its existence. The income of the +company might be wasting away, and the loss never suspected until +the quarterly returns from the meters were obtained from the +inspectors. Only then would it be discovered that there must be a +great leak (or it might be several leaks) somewhere. But how would +it be possible to trace them among 20 or 30 miles of buried pipes? +We cannot break up the public streets. The very existence of the +concern depends upon (1) the <i>daily</i> checking of the meter +returns, and comparison with the output from the air compressors, +so as to ascertain the amount of leakage; (2) facility for tracing +the locality of a leak; and (3) easy access to the mains with the +minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the +pipes are laid in concrete troughs, near the surface of the road, +with removable concrete covers strong enough to stand any overhead +traffic. At intervals there are junctions for service connections, +with street boxes and covers serving as inspection chambers. These +chambers are also provided over the ball-valves, which serve as +stop-valves in case of necessity, and are so arranged that in case +of a serious breach in the portion of main between any two of them, +the rush of air to the breach will blow them up to the +corresponding seats and block off the broken portion of main. The +air space around the pipe in the concrete trough will convey for a +long distance the whistling noise of a leak; and the inspectors, by +listening at the inspection openings, will thus be enabled to +rapidly trace their way almost to the exact spot where there is an +escape. They have then only to remove the top surface of road metal +and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring +from the nearest street opening, the inspectors would know where to +break open the road to arrive at the probable locality of the leak. +A very slight leak can be heard a long way off by its peculiar +whistling sound.</p> + +<p class="ctr"><a href="./illustrations/6a.png"><img src= +"./illustrations/6a_th.jpg" alt="COMPRESSED AIR POWER"></a></p> + +<p class="ctr">COMPRESSED AIR POWER</p> + +<p>The next point is to obtain a daily report of the condition of +the mains and the amount of leakage. It would be impracticable to +employ an army of meter inspectors to take the records daily from +all the meters in the district. We therefore adopt the method of +electric signaling shown in the second drawing. In the engineer's +office, at the central station, is fixed the dial shown in Fig. 1. +Each consumer's meter is fitted with the contact-making apparatus +shown in Pig. 4, and in an enlarged form in Figs. 5 and 6, by which +a current is sent round the electro-magnet, D (Fig. 1), attracting +the armature, and drawing the disk forward sufficiently for the +roller at I to pass over the center of one of the pins, and so drop +in between that and the next pin, thus completing the motion, and +holding the disk steadily opposite the figure. This action takes +place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose +one meter should be moving very slowly, and so retaining contact +for some time, while other meters were working rapidly; the +armature at D would then be held up to the magnet by the prolonged +contact maintained by the slow moving meter, and so prevent the +quick working meters from actuating it; and they would therefore +pass the contact points without recording. A meter might also stop +dead at the point of contact on shutting off the air, and so hold +up the armature; thus preventing others from acting. To obviate +this, we apply the disengaging apparatus shown at L (Fig. 4). The +contact maker works on the center, m, having an armature on its +opposite end. On contact being made, at the same time that the +magnet, D, is operated, the one at L is also operated, attracting +the armature, and throwing over the end of the contact maker, +l¹, on to the non-conducting side of the pin on the disk. Thus +the whole movement is rendered practically instantaneous, and the +magnet at D is set at liberty for the next operation. A resistance +can be interposed at L, if necessary, to regulate the period of the +operation. The whole of the meters work the common dial shown in +Fig. 1, on which the gross results only are recorded; and this is +all we want to know in this way. The action is so rapid, owing to +the use of the magnetic disengaging gear, that the chances of two +or more meters making contact at the same moment are rendered +extremely small. Should such a thing happen, it would not matter, +as it is only approximate results that we require in this case; and +the error, if any, would add to the apparent amount of leakage, and +so be on the right side. Of course, the record of each consumer's +meter would be taken by the inspector at the end of every quarter, +in order to make out the bill; and the totals thus obtained would +be checked by the gross results indicated by the main dial. In this +way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected +to an extremely accurate measurement. At the end of the working +day, the engineer has merely to take down from the dial in his +office the total record of air measured to the consumers, also the +output of air from the compressors, which he ascertains by means of +a continuous counter on the engines, and the difference between the +two will represent the loss. If the loss is trifling, he will pass +it over; if serious, he will send out his inspectors to trace it. +Thus there could be no long continued leakage, misuse, or robbery +of the air, without the company becoming aware of the fact, and so +being enabled to take measures to stop or prevent it. The foregoing +are absolutely essential adjuncts to any scheme of public motive +power supply by compressed air, without which we should be working +in the dark, and could never be sure whether the company were +losing or making money. With them, we know where we are and what we +are doing.</p> + +<p>Referring to the estimates given in Table I., I may explain that +the item of repairs and renewals covers 10 per cent. on boilers and +gas producers, 5 per cent. on engines, 5 per cent. on buildings, +and 5 per cent. on mains. Considering that the estimates include +ample fitting shops, with the best and most suitable tools, and +that the wages list includes a staff of men whose chief work would +be to attend to repairs, etc., I think the above allowances ample. +Each item also includes 5 per cent. for contingencies.</p> + +<p>I have commenced by giving all the preceding detail, in order to +show the groundwork on which I base the estimate of the cost of +compressed air power to consumers, in terms of indicated horse +power per annum, as given in Table II. I may say that, in +estimating the engine power and coal consumption, I have not, as in +the original report, made purely theoretical calculations, but have +taken diagrams from engines in actual use (although of somewhat +smaller size than those intended to be employed), and have worked +out the results therefrom. It will, I hope, be seen that, with all +the safeguards we have provided, we may fairly reckon upon having +for sale the stated quantity of air produced by means of the plant, +as estimated, and at the specified annual cost; and that therefore +the statement of cost per indicated horse power per annum may be +fairly relied upon. Thus the cost of compressed air to the +consumer, based upon an <i>average</i> charge of 5d. per 1,000 +cubic feet, will vary from £6 14s. per indicated horse power +per annum to £18 13s. 3d., according to circumstances and +mode of application.</p> + +<p>A compressed air motor is an exceedingly simple machine--much +simpler than an ordinary steam engine. But the air may also be used +in an ordinary steam engine; and in this case it can be much +simplified in many details. Very little packing is needed, as there +is no nuisance from gland leakage; the friction is therefore very +slight. Pistons and glands are packed with soapstone, or other +self-lubricating packing; and no oil is required except for +bearings, etc. The company will undertake the periodical inspection +and overhauling of engines supplied with their power, all which is +included in the estimates. The total cost to consumers, with air at +an average of 5d. per 1,000 cubic feet, may therefore be fairly +taken as follows:</p> + +<pre> + Min. Max. + Cost of air used £6 14 0½ £18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 12½ per cent. on + £10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + £8 19 0½ £20 18 3 +</pre> + +<p>The maximum case would apply only to direct acting engines, such +as Tangye pumps, air power hammers, etc., where the air is full on +till the end of the stroke, and where there is no expansion. The +minimum given is at the average rate of 5d. per 1,000 cubic feet; +but as there will be rates below this, according to a sliding +scale, we may fairly take it that the lowest charge will fall +considerably below £6 per indicated horse power per +annum.--<i>Journal of Gas Lighting</i>.</p> + +<hr> +<p><a name="7"></a></p> + +<h2>THE BERTHON COLLAPSIBLE CANOE.</h2> + +<p>An endeavor has often been made to construct a canoe that a +person can easily carry overland and put into the water without +aid, and convert into a sailboat. The system that we now call +attention to is very well contrived, very light, easily taken +apart, and for some years past has met with much favor.</p> + +<p class="ctr"><img src="./illustrations/6b.png" alt= +"FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT."></p> + +<p class="ctr">FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.</p> + +<p>Mr. Berthon's canoes are made of impervious oil-skin. Form is +given them by two stiff wooden gunwales which are held in position +by struts that can be easily put in and taken out. The model shown +in the figure is covered with oiled canvas, and is provided with a +double paddle and a small sail. Fig. 2 represents it collapsed and +being carried overland.</p> + +<p class="ctr"><img src="./illustrations/6c.png" alt= +"FIG. 2.--THE SAME BEING CARRIED OVERLAND."></p> + +<p class="ctr">FIG. 2.--THE SAME BEING CARRIED OVERLAND.</p> + +<p>Mr. Berthon is manufacturing a still simpler style, which is +provided with two oars, as in an ordinary canoe. This model, which +is much used in England by fishermen and hunters, has for several +years past been employed in the French navy, in connection with +movable defenses. At present, every torpedo boat carries one or two +of these canoes, each composed of two independent halves that may +be put into the water separately or be joined together by an iron +rod.</p> + +<p>These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure +without danger.[1]--<i>La Nature</i>.</p> + +<p>[Footnote 1: For detailed description see SUPPLEMENT, No. +84.]</p> + +<hr> +<p><a name="8"></a></p> + +<h2>THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN +STEAM RAILROAD.</h2> + +<p>There was great excitement in Nürnberg on the 7th of +December, 1835, on which day the first German railroad was opened. +The great square on which the buildings of the Nürnberg and +Furth "Ludwig's Road" stood, the neighboring streets, and, in fact, +the whole road between the two cities, was filled with a crowd of +people who flocked from far and near to see the wonderful +spectacle. For the first time, a railroad train filled with +passengers was to be drawn from Nürnberg to Furth by the +invisible power of the steam horse. At eight o'clock in the +morning, the civil and military authorities, etc., who took part in +the celebration were assembled on the square, and the gayly +decorated train started off to an accompaniment of music, +cannonading, cheering, etc. Everything passed off without an +accident; the work was a success. The engraving in the lower +right-hand corner represents the engine and cars of this road.</p> + +<p>It will be plainly seen that such a revolution could not be +accomplished easily, and that much sacrifice and energy were +required of the leaders in the enterprise, prominent among whom was +the merchant Johannes Scharrer, who is known as the founder of the +"Ludwig's Road."</p> + +<p>One would naturally suppose that such an undertaking would have +met with encouragement from the Bavarian Government, but this was +not the case. The starters of the enterprise met with opposition on +every side; much was written against it, and many comic pictures +were drawn showing accidents which would probably occur on the much +talked of road. Two of these pictures are shown in the accompanying +large engraving, taken from the <i>Illustrirte Zeitung</i>. As +shown in the center picture, right hand, it was expected by the +railway opponents that trains running on tracks at right angles +must necessarily come in collision. If anything happened to the +engine, the passengers would have to get out and push the cars, as +shown at the left.</p> + +<p class="ctr"><a href="./illustrations/7a.png"><img src= +"./illustrations/7a_th.jpg" alt=""></a></p> + +<p class="ctr">JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF +THE OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--<br> +AT NURNBERG</p> + +<p>Much difficulty was experienced in finding an engineer capable +of attending to the construction of the road; and at first it was +thought that it would be best to engage an Englishman, but finally +Engineer Denis, of Munich, was appointed. He had spent much time in +England and America studying the roads there, and carried on this +work to the entire satisfaction of the company.</p> + +<p>All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to +be given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first +prize in the competitive trials at Rainhill in 1829, delivered an +engine of ten horse power, which is still known in Nürnberg as +"Der Englander."</p> + +<p>Fifty years have passed, and, as Johannes Scharrer predicted, +the Ludwig's Road has become a permanent institution, though it now +forms only a very small part of the network of railroads which +covers every portion of Germany. What changes have been made in +railroads during these fifty years! Compare the present locomotives +with the one made by Cugnot in 1770, shown in the upper left-hand +cut, and with the work of the pioneer Geo. Stephenson, who in 1825 +constructed the first passenger railroad in England, and who +established a locomotive factory in Newcastle in 1824. Geo. +Stephenson was to his time what Mr. Borsig, whose great works at +Moabit now turn out from 200 to 250 locomotives a year, is to our +time.</p> + +<p>Truly, in this time there can be no better occasion for a +celebration of this kind than the fiftieth anniversary of the +opening of the first German railroad, which has lately been +celebrated by Nürnberg and Furth.</p> + +<p>The lower left-hand view shows the locomotive De Witt Clinton, +the third one built in the United States for actual service, and +the coaches. The engine was built at the West Point Foundry, and +was successfully tested on the Mohawk and Hudson Railroad between +Albany and Schenectady on Aug. 9, 1831.</p> + +<hr> +<p><a name="9"></a></p> + +<h2>IMPROVED COAL ELEVATOR.</h2> + +<p>An illustration of a new coal elevator is herewith presented, +which presents advantages over any incline yet used, so that a +short description may be deemed interesting to those engaged in the +coaling and unloading of vessels. The pen sketch shows at a glance +the arrangement and space the elevator occupies, taking less ground +to do the same amount of work than any other mode heretofore +adopted, and the first cost of erecting is about the same as any +other.</p> + +<p>When the expense of repairing damages caused by the ravages of +winter is taken into consideration, and no floats to pump out or +tracks to wash away, the advantages should be in favor of a +substantial structure.</p> + +<p>The capacity of this hoist is to elevate 80,000 bushels in ten +hours, at less than one-half cent per bushel, and put coal in +elevator, yard, or shipping bins.</p> + +<p class="ctr"><a href="./illustrations/8a.png"><img src= +"./illustrations/8a_th.jpg" alt="IMPROVED COAL ELEVATOR."></a></p> + +<p class="ctr">IMPROVED COAL ELEVATOR.</p> + +<p>The endless wire rope takes the cars out and returns them, +dispensing with the use of train riders.</p> + +<p>A floating elevator can distribute coal at any hatch on steam +vessels, as the coal has to be handled but once; the hoist +depositing an empty car where there is a loaded one in boat or +barge, requiring no swing of the vessel.</p> + +<p>Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor +and builder, and has them in use in the U.S. engineering +service.--<i>Coal Trade Journal</i>.</p> + +<hr> +<p><a name="10"></a></p> + +<h2>STEEL-MAKING LADLES.</h2> + +<p>The practice of carrying melted cast iron direct from the blast +furnace to the Siemens hearth or the Bessemer converter saves both +money and time. It has rendered necessary the construction of +special plant in the form of ladles of dimensions hitherto quite +unknown. Messrs. Stevenson & Co., of Preston, make the +construction of these ladles a specialty, and by their courtesy, +says <i>The Engineer</i>, we are enabled to illustrate four +different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel +foundry work, and one of these for the Siemens-Martin process is +illustrated by Fig. 1. These ladles are made in sizes to take from +five to fifteen ton charges, or larger if required, and are mounted +on a very strong carriage with a backward and forward traversing +motion, and tipping gear for the ladle. The ladles are butt +jointed, with internal cover strips, and have a very strong band +shrunk on hot about half way in the depth of the ladle. This forms +an abutment for supporting the ladle in the gudgeon band, being +secured to this last by latch bolts and cotters. The gearing is +made of cast steel, and there is a platform at one end for the +person operating the carriage or tipping the ladle. Stopper gear +and a handle are fitted to the ladles to regulate the flow of the +molten steel from the nozzle at the bottom.</p> + +<p class="ctr"><a href="./illustrations/8b.png"><img src= +"./illustrations/8b_th.jpg" alt= +"LADLES FOR CARRYING MOLTEN IRON AND STEEL."></a></p> + +<p class="ctr">LADLES FOR CARRYING MOLTEN IRON AND STEEL.</p> + +<p>Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. +It requires no description. Fig. 3 shows a tremendous ladle +constructed for the North-Eastern Steel Company, for carrying +molten metal from the blast furnace to the converter. It holds ten +tons with ease. It is an exceptionally strong structure. The +carriage frame is constructed throughout of 1 in. wrought-iron +plated, and is made to suit the ordinary 4 ft. 8½ in. +railway gauge. The axle boxes are cast iron, fitted with gun-metal +steps. The wheels are made of forged iron, with steel tires and +axles. The carriage is provided with strong oak buffers, planks, +and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of ½ in. +wrought-iron plates, butt jointed, and double riveted butt straps. +The trunnions and flange couplings are of cast steel. The tipping +gear, clearly shown in the engraving, consists of a worm and wheel, +both of steel, which can be fixed on either side of the ladle as +may be desired. From this it will be seen that Messrs. Stevenson +& Co. have made a thoroughly strong structure in every respect, +and one, therefore, that will commend itself to most steel makers. +We understand that these carriages are made in various designs and +sizes to meet special requirements. Thus, Fig. 4 shows one of +different design, made for a steel works in the North. This is also +a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great +care and honesty of purpose is required in making these structures. +A breakdown might any moment pour ten tons of molten metal on the +ground, with the most horrible results.</p> + +<hr> +<p><a name="13"></a></p> + +<h2>APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON +THE SURFACE OF CONDUCTORS.</h2> + +<p>Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple +and ingenious apparatus which permits of demonstrating that +electricity develops only on the surface of conductors. It consists +(see figure) essentially of a yellow-metal disk, M, fixed to an +insulating support, F, and carrying a concentric disk of ebonite, +H. This latter receives a hollow and closed hemisphere, J, of +yellow metal, whose base has a smaller diameter than that of the +disk, H, and is perfectly insulated by the latter. Another +yellow-metal hemisphere, S, open below, is connected with an +insulating handle, G. The basal diameter of this second hemisphere +is such that when the latter is placed over J its edge rests upon +the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a +hollow, closed hemisphere that imprisons the hemisphere, J, which +is likewise hollow and closed, and perfectly insulated from the +former.</p> + +<p class="ctr"><img src="./illustrations/9a.png" alt=""></p> + +<p>The shell, S, is provided internally with a curved yellow-metal +spring, whose point of attachment is at B, and whose free extremity +is connected with an ebonite button, K, which projects from the +shell, S. By pressing this button, a contact may be established +between the external hemisphere (formed of the pieces, S and M), +and the internal one, J. As soon as the button is left to itself, +the spring again begins to bear against the interior surface of S, +and the two hemispheres are again insulated.</p> + +<p>The experiment is performed in this wise: The shell, S, is +removed. Then a disk of steatite affixed to an insulating handle is +rubbed for a few instants with a fox's "brush," and held near J +until a spark occurs. Then the apparatus is grasped by the support, +F, and an elder-pith ball suspended by a flaxen thread from a good +conducting support is brought near J. The ball will be quickly +repelled, and care must be taken that it does not come into contact +with J. After this the apparatus is placed upon a table, the shell, +S, is taken by its handle, G, and placed in the position shown in +the figure, and a momentary contact is established between the two +hemispheres by pressing the button, K. Then the shell, S, is +lifted, and the disk, M, is touched at the same time with the other +hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, +thus proving that all the electricity passed from J to S at the +moment of contact.--<i>La Lumiere Electrique</i>.</p> + +<hr> +<p><a name="14"></a></p> + +<h2>THE COLSON TELEPHONE.</h2> + +<p>This apparatus has recently been the object of some experiments +which resulted in its being finally adopted in the army. We think +that our readers will read a description of it with interest. Its +mode of construction is based upon a theoretic conception of the +lines of force, which its inventor explains as follows in his +Elementary Treatise on Electricity:</p> + +<p>"To every position of the disk of a magnetic telephone with +respect to the poles of the magnet there corresponds a certain +distribution of the lines of force, which latter shift themselves +when the disk is vibrating. If the bobbin be met by these lines in +motion, there will develop in its wire a difference of potential +that, according to Faraday's law, will be proportional to their +number. All things equal, then, a telephone transmitter will be so +much the more potent in proportion as the lines set in motion by +the vibrations of the disk and meeting the bobbin wire are greater +in number. In like manner, a receiver will be so much the more +potent in proportion as the lines of force, set in motion by +variations in the induced currents that are traversing the bobbin +and meeting the disk, are more numerous. It will consequently be +seen that, generally speaking, it is well to send as large a number +of lines of force as possible through the bobbin."</p> + +<p class="ctr"><img src="./illustrations/9b.png" alt= +"FIG. 1.--THE COLSON TELEPHONE."></p> + +<p class="ctr">FIG. 1.--THE COLSON TELEPHONE.</p> + +<p>In order to obtain such a result, the thin tin-plate disk has to +be placed between the two poles of the magnet. The pole that +carries the fine wire bobbin acts at one side and in the center of +the disk, while the other is expanded at the extremity and acts +upon the edge and the other side. This pole is separated from the +disk by a copper washer, and the disk is thus wholly immersed in +the magnetic field, and is traversed by the lines of force +radiatingly.</p> + +<p>This telephone is being constructed by Mr. De Branville, with +the greatest care, in the form of a transmitter (Fig. 2) and +receiver (Fig. 3). At A may be seen the magnet with its central +pole, P, and its eccentric one, P'. This latter traverses the +vibrating disk, M, through a rubber-lined aperture and connects +with the soft iron ring, F, that forms the polar expansion. These +pieces are inclosed in a nickelized copper box provided with a +screw cap, C. The resistance of both the receiver and transmitter +bobbin is 200 ohms.</p> + +<p class="ctr"><img src="./illustrations/9c.png" alt= +"FIG. 2.--TRANSMITTER TAKEN APART."></p> + +<p class="ctr">FIG. 2.--TRANSMITTER TAKEN APART.</p> + +<p>The transmitter is 3½ in. in diameter, and is provided +with a re-enforcing mouthpiece. It is regulated by means of a screw +which is fixed in the bottom of the box, and which permits of +varying the distance between the disk and the core that forms the +central pole of the magnet. The regulation, when once effected, +lasts indefinitely. The regulation of the receiver, which is but +2¼ in. in diameter, is performed once for all by the +manufacturer. One of the advantages of this telephone is that its +regulation is permanent. Besides this, it possesses remarkable +power and clearness, and is accompanied with no snuffling sounds, a +fact doubtless owing to all the molecules of the disk being +immersed in the magnetic field, and to the actions of the two poles +occurring concentrically with the disk. As we have above said, this +apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used +by the artillery service in the organization of observatories from +which to watch firing, and the receiver is added to the apparatus +pertaining to military telegraphy. The two small receivers are held +to the lens of the operator by the latter's hat strap, while the +transmitter is suspended in a case supported by straps, with the +mouthpieces near the face (Fig. 1).</p> + +<p>In the figure, the case is represented as open, so as to show +the transmitter. The empty compartment below is designed for the +reception and carriage of the receivers, straps, and flexible +cords. This arrangement permits of calling without the aid of +special apparatus, and it has also the advantage of giving entire +freedom to the man on observation, this being something that is +indispensable in a large number of cases.</p> + +<p class="ctr"><img src="./illustrations/9d.png" alt= +"FIG. 3.--RECEIVER TAKEN APART."></p> + +<p class="ctr">FIG. 3.--RECEIVER TAKEN APART.</p> + +<p>In certain applications, of course, the receivers may be +combined with a microphone; yet on an aerial as well as on a +subterranean line the transmitter produces effects which, as +regards intensity and clearness, are comparable with those of a +pile transmitter.</p> + +<p>Stations wholly magnetic may be established by adding to the +transmitter and two receivers a Sieur phonic call, which will +actuate them powerfully, and cause them to produce a noise loud +enough for a call. It would be interesting to try this telephone on +a city line, and to a great distance on those telegraph lines that +are provided with the Van Rysselberghe system. Excellent results +would certainly be obtained, for, as we have recently been enabled +to ascertain, the voice has a remarkable intensity in this +telephone, while at the same time perfectly preserving its +quality.--<i>La Nature</i>.</p> + +<hr> +<p>[NATURE.]</p> + +<p><a name="15"></a></p> + +<h2>THE MELDOMETER.</h2> + +<p>The apparatus which I propose to call by the above name +(μελδω, to melt) consists of an +adjunct to the mineralogical microscope, whereby the melting-points +of minerals may be compared or approximately determined and their +behavior watched at high temperatures either alone or in the +presence of reagents.</p> + +<p>As I now use it, it consists of a narrow ribbon of platinum (2 +mm. wide) arranged to traverse the field of the microscope. The +ribbon, clamped in two brass clamps so as to be readily renewable, +passes bridgewise over a little scooped-out hollow in a disk of +ebony (4 cm. diam.). The clamps also take wires from a battery (3 +Groves cells); and an adjustable resistance being placed in +circuit, the strip can be thus raised in temperature up to the +melting-point of platinum.</p> + +<p>The disk being placed on the stage of the microscope the +platinum strip is brought into the field of a 1" objective, +protected by a glass slip from the radiant heat. The observer is +sheltered from the intense light at high temperatures by a wedge of +tinted glass, which further can be used in photometrically +estimating the temperature by using it to obtain extinction of the +field. Once for all approximate estimations of the temperature of +the field might be made in terms of the resistance of the platinum +strip, the variation of such resistance with rise of temperature +being known. Such observations being made on a suitably protected +strip might be compared with the wedge readings, the latter being +then used for ready determinations. Want of time has hindered me +from making such observations up to this.</p> + +<p>The mineral to be experimented on is placed in small fragments +near the center of the platinum ribbon, and closely watched while +the current is increased, till the melting-point of the substance +is apparent. Up to the present I have only used it comparatively, +laying fragments of different fusibilities near the specimen. In +this way I have melted beryl, orthoclase, and quartz. I was much +surprised to find the last mineral melt below the melting-point of +platinum. I have, however, by me as I write, a fragment, formerly +clear rock-crystal, so completely fused that between crossed Nicols +it behaves as if an amorphous body, save in the very center where a +speck of flashing color reveals the remains of molecular symmetry. +Bubbles have formed in the surrounding glass.</p> + +<p>Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way.</p> + +<p>Topaz whitens to a milky glass--apparently decomposing, throwing +out filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot +platinum, causes rings of color to appear round the specimen. I +have now been using the apparatus for nearly a month, and in its +earliest days it led me right in the diagnosis of a microscopical +mineral, iolite, not before found in our Irish granite, I think. +The unlooked-for characters of the mineral, coupled with the +extreme minuteness of the crystals, led me previously astray, until +my meldometer fixed its fusibility for me as far above the +suspected bodies.</p> + +<p>Carbon slips were at first used, as I was unaware of the +capabilities of platinum.</p> + +<p>A form of the apparatus adapted, at Prof. Fitzgerald's +suggestion, to fit into the lantern for projection on the screen +has been made for me by Yeates. In this form the heated conductor +passes both below and above the specimen, which is regarded from a +horizontal direction.</p> + +<p>J. JOLY.</p> + +<p>Physical Laboratory, Trinity College, Dublin.</p> + +<hr> +<p>[AMERICAN ANNALS OF THE DEAF AND DUMB.]</p> + +<p><a name="16"></a></p> + +<h2>TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF +DEAF-MUTES.</h2> + +<p>Progress in electrical science is daily causing the world to +open its eyes in wonder and the scientist to enlarge his hopes for +yet greater achievements. The practical uses to which this subtile +fluid, electricity, is being put are causing changes to be made in +time-tested methods of doing things in domestic, scientific, and +business circles, and the time has passed when startling +propositions to accomplish this or that by the assistance of +electricity are dismissed with incredulous smiles. This being the +case, no surprise need follow the announcement of a device to +facilitate the imparting of instruction to deaf children which +calls into requisition some service from electricity.</p> + +<p>The sense of touch is the direct medium contemplated, and it is +intended to convey, with accuracy and rapidity, messages from the +operator (the teacher) to the whole class simultaneously by +electrical transmission.[1]</p> + +<p>[Footnote 1: By the same means two deaf-mutes, miles apart, +might converse with each other, and the greatest difficulty in the +way of a deaf-mute becoming a telegraph operator, that of receiving +messages, would be removed. The latter possibilities are +incidentally mentioned merely as of scientific interest, and not +because of their immediate practical value. The first mentioned use +to which the device may be applied is the one considered by the +writer as possibly of practical value, the consideration of which +suggested the appliance to him.]</p> + +<p>An alphabet is formed upon the palm of the left hand and the +inner side of the fingers, as shown by the accompanying cut, which, +to those becoming familiar with it, requires but a touch upon a +certain point of the hand to indicate a certain letter of the +alphabet.</p> + +<p>A rapid succession of touches upon various points of the hand is +all that is necessary in spelling a sentence. The left hand is the +one upon which the imaginary alphabet is formed, merely to leave +the right hand free to operate without change of position when two +persons only are conversing face to face.</p> + +<p>The formation of the alphabet here figured is on the same +principle as one invented by George Dalgarno, a Scottish +schoolmaster, in the year 1680, a cut of which maybe seen on page +19 of vol. ix. of the <i>Annals</i>, accompanying the reprint of a +work entitled "<i>Didascalocophus</i>." Dalgarno's idea could only +have been an alphabet to be used in conversation between two +persons <i>tête à tête</i>, and--except to a +limited extent in the Horace Mann School and in Professor Bell's +teaching--has not come into service in the instruction of +deaf-mutes or as a means of conversation. There seems to have been +no special design or system in the arrangement of the alphabet into +groups of letters oftenest appearing together, and in several +instances the proximity would seriously interfere with distinct +spelling; for instance, the group "u," "y," "g," is formed upon the +extreme joint of the little finger. The slight discoverable system +that seems to attach to his arrangement of the letters is the +placing of the vowels in order upon the points of the fingers +successively, beginning with the thumb, intended, as we suppose, to +be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly +as another. If any arrangement has advantage over another, we +consider it the one which has so grouped the letters as to admit of +an increased rapidity of manipulation. The arrangement of the above +alphabet, it is believed, does admit of this. Yet it is not claimed +that it is as perfect as the test of actual use may yet make it. +Improvements in the arrangement will, doubtless, suggest +themselves, when the alterations can be made with little need of +affecting the principle.</p> + +<p>In order to transmit a message by this alphabet, the following +described appliance is suggested: A matrix of cast iron, or made of +any suitable material, into which the person receiving the message +(the pupil) places his left hand, palm down, is fixed to the table +or desk. The matrix, fitting the hand, has twenty-six holes in it, +corresponding in position to the points upon the hand assigned to +the different letters of the alphabet. In these holes are small +styles, or sharp points, which are so placed as but slightly to +touch the hand. Connected with each style is a short line of wire, +the other end of which is connected with a principal wire leading +to the desk of the operator (the teacher), and there so arranged as +to admit of opening and closing the circuit of an electric current +at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric +impulses, intended to act mechanically upon all the styles +connected with it. By these impulses, produced by the will of the +sender, the styles are driven upward with a quick motion, but with +only sufficient force to be felt and located upon the hand by the +recipient. Twenty-six of these principal or primary wires are run +from the teacher's desk (there connected with as many buttons) +under the floor along the line of pupils' desks. From each matrix +upon the desk run twenty-six secondary wires down to and severally +connecting with the twenty-six primary wires under the floor. The +whole system of wires is incased so as to be out of sight and +possibility of contact with foreign substances. The keys or buttons +upon the desk of the teacher are systematically arranged, somewhat +after the order of those of the type writer, which allows the use +of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," +"c," etc., to "z," and an electric current over the primary wire +running from a certain button (say the one labeled "a") affects +only those secondary wires connected with the styles that, when +excited, produce upon the particular spot of the hands of the +receivers the tactile impression to be interpreted as "a." And so, +whenever the sender touches any of the buttons on his desk, +immediately each member of the class feels upon the palm of his +hand the impression meant to be conveyed. The contrivance will +admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric +bell. It was first thought of conveying the impressions directly by +slight electric shocks, without the intervention of further +mechanical apparatus, but owing to a doubt as to the physical +effect that might be produced upon the persons receiving, and as to +whether the nerves might not in time become partly paralyzed or so +inured to the effect as to require a stronger and stronger current, +that idea was abandoned, and the one described adopted. A diagram +of the apparatus was submitted to a skillful electrical engineer +and machinist of Hartford, who gave as his opinion that the scheme +was entirely feasible, and that a simple and comparatively +inexpensive mechanism would produce the desired result.</p> + +<p class="ctr"><img src="./illustrations/10a.png" alt= +"TOUCH TRANSMISSION BY ELECTRICITY."></p> + +<p class="ctr">TOUCH TRANSMISSION BY ELECTRICITY.</p> + +<p>The matter now to consider, and the one of greater interest to +the teacher of deaf children, is, Of what utility can the device be +in the instruction of deaf-mutes? What advantage is there, not +found in the prevailing methods of communication with the deaf, +i.e., by gestures, dactylology, speech and speech-reading, and +writing?</p> + +<p>I. The language of gestures, first systematized and applied to +the conveying of ideas to the deaf by the Abbe de l'Epee during the +latter part of the last century, has been, in America, so developed +and improved upon by Gallaudet, Peet, and their successors, as to +leave but little else to be desired for the purpose for which it +was intended. The rapidity and ease with which ideas can be +expressed and understood by this "language" will never cease to be +interesting and wonderful, and its value to the deaf can never fail +of being appreciated by those familiar with it. But the genius of +the language of signs is such as to be in itself of very little, if +any, direct assistance in the acquisition of syntactical language, +owing to the diversity in the order of construction existing +between the English language and the language of signs. Sundry +attempts have been made to enforce upon the sign-language +conformity to the English order, but they have, in all cases known +to the writer, been attended with failure. The sign-language is as +immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given +with great success upon the basis of the sign-language. But in all +such exercises there must be a translation from one language to the +other. The desideratum still exists of an increased percentage of +pupils leaving our schools for the deaf, possessing a facility of +expression in English vernacular. This want has been long felt, and +endeavoring to find a reason for the confessedly low percentage, +the sign-language has been too often unjustly accused. It is only +when the sign-language is abused that its merit as a means of +instruction degenerates. The most ardent admirers of a proper use +of signs are free to admit that any excessive use by the pupils, +which takes away all opportunities to express themselves in +English, is detrimental to rapid progress in English +expression.</p> + +<p>II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as +one of the elements of the American or eclectic method. This +advantage, however, is not of so great importance as to outweigh +the disadvantages when, as has honestly been attempted, it asserts +its independence of other methods. Very few persons indeed, even +after long practice, become sufficiently skillful in spelling on +the fingers to approximate the rapidity of speech. But were it +possible for all to become rapid spellers, another very important +requisite is necessary before the system could be a perfect one, +that is, the ability to <i>read</i> rapid spelling. The number of +persons capable of reading the fingers beyond a moderate degree of +rapidity is still less than the number able to spell rapidly. While +it is physically possible to follow rapid spelling for twenty or +thirty minutes, it can scarcely be followed longer than that. So +long as this is true, dactylology can hardly claim to be more than +one of the <i>elements</i> of a system of instruction for the +deaf.</p> + +<p>III. Articulate speech is another of the elements of the +eclectic method, employed with success inversely commensurate with +the degree of deficiency arising from deafness. Where the English +order is already fixed in his mind, and he has at an early period +of life habitually used it, there is comparatively little +difficulty in instructing the deaf child by speech, especially if +he have a quick eye and bright intellect. But the number so favored +is a small percentage of the great body of deaf-mutes whom we are +called upon to educate. When it is used as a <i>sole</i> means of +educating the deaf as a class its inability to stand alone is as +painfully evident as that of any of the other component parts of +the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to +what a word is if spelled slowly enough, and if its meaning has +been learned. This cannot be said of speech. Between many words +there is not, when uttered, the slightest visible distinction. +Between a greater number of others the distinction is so slight as +to cause an exceedingly nervous hesitation before a guess can be +given. Too great an imposition is put upon the eye to expect it to +follow unaided the extremely circumscribed gestures of the organs +of speech visible in ordinary speaking. The ear is perfection as an +interpreter of speech to the brain. It cannot correctly be said +that it is <i>more</i> than perfection. It is known that the ear, +in the interpretation of vocal sounds, is capable of distinguishing +as many as thirty-five sounds per second (and oftentimes more), and +to follow a speaker speaking at the rate of more than two hundred +words per minute. If this be perfection, can we expect the +<i>eye</i> of ordinary mortal to reach it? Is there wonder that the +task is a discouraging one for the deaf child?</p> + +<p>But it has been asserted that while a large percentage +(practically all) of the deaf <i>can</i>, by a great amount of +painstaking and practice, become speech readers in some small +degree, a relative degree of facility in articulation is not nearly +so attainable. As to the accuracy of this view, the writer cannot +venture an opinion. Judging from the average congenital deaf-mute +who has had special instruction in speech, it can safely be +asserted that their speech is laborious, and far, very far, from +being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that +as an unaided means of instruction it cannot be a success, for +English neither understood when spoken, nor spoken by the pupil, +cannot but remain a foreign language, requiring to pass through +some other form of translation before it becomes intelligible.</p> + +<p>There are the same obstacles in the use of the written or +printed word as have been mentioned in connection with dactylology, +namely, lack of rapidity in conveying impressions through the +medium of the English sentence.</p> + +<p>I have thus hastily reviewed the several means which teachers +generally are employing to impart the use of English to deaf +pupils, for the purpose of showing a common difficulty. The many +virtues of each have been left unnoticed, as of no pertinence to +this article.</p> + +<p>The device suggested at the beginning of this paper, claiming to +be nothing more than a school room appliance intended to supplement +the existing means for giving a knowledge and practice of English +to the deaf, employs as its interpreter a different sense from the +one universally used. The sense of sight is the sole dependence of +the deaf child. Signs, dactylology, speech reading, and the written +and printed word are all dependent upon the eye for their value as +educational instruments. It is evident that of the two senses, +sight and touch, if but one could be employed, the choice of sight +as the one best adapted for the greatest number of purposes is an +intelligent one; but, as the choice is not limited, the question +arises whether, in recognizing the superior adaptability to our +purpose of the one, we do not lose sight of a possibly important, +though secondary, function in the other. If sight were +all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we +acquire our vernacular is of divine, and not of human, origin, and +the senses designed for special purposes are not interchangeable +without loss. The theory that the loss of a certain sense is +nearly, if not quite, compensated for by increased acuteness of the +remaining ones has been exploded. Such a theory accuses, in +substance, the Maker of creating something needless, and is +repugnant to the conceptions we have of the Supreme Being. When one +sense is absent, the remaining senses, in order to equalize the +loss, have imposed upon them an unusual amount of activity, from +which arises skill and dexterity, and by which the loss of the +other sense is in some measure alleviated, but not supplied. No +<i>additional</i> power is given to the eye after the loss of the +sense of hearing other than it might have acquired with the same +amount of practice while both faculties were active. The fact, +however, that the senses, in performing their proper functions, are +not overtaxed, and are therefore, in cases of emergency, capable of +being extended so as to perform, in various degrees, additional +service, is one of the wise providences of God, and to this fact is +due the possibility of whatever of success is attained in the work +of educating the deaf, as well as the blind.</p> + +<p>In the case of the blind, the sense of touch is called into +increased activity by the absence of the lost sense; while in the +case of the deaf, sight is asked to do this additional service. A +blind person's education is received principally through the +<i>two</i> senses of hearing and touch. Neither of these faculties +is so sensible to fatigue by excessive use as is the sense of +sight, and yet the eye has, in every system of instruction applied +to the deaf, been the sole medium. In no case known to the writer, +excepting in the celebrated case of Laura Bridgman and a few others +laboring under the double affliction of deafness and blindness, has +the sense of touch been employed as a means of instruction.[1]</p> + +<p>[Footnote 1: This article was written before Professor Bell had +made his interesting experiments with his "parents' class" of a +touch alphabet, to be used upon the pupil's shoulder in connection +with the oral teaching.--E.A.F.]</p> + +<p>Not taking into account the large percentage of myopes among the +deaf, we believe there are other cogent reasons why, if found +practicable, the use of the sense of touch may become an important +element in our eclectic system of teaching. We should reckon it of +considerable importance if it were ascertained that a portion of +the same work now performed by the eye could be accomplished +equally as well through feeling, thereby relieving the eye of some +of its onerous duties.</p> + +<p>We see no good reason why such accomplishment may not be +wrought. If, perchance, it were discovered that a certain portion +could be performed in a more efficient manner, its value would thus +be further enhanced.</p> + +<p>In theory and practice, the teacher of language to the deaf, by +whatever method, endeavors to present to the eye of the child as +many completed sentences as are nominally addressed to the +ear--having them "caught" by the eye and reproduced with as +frequent recurrence as is ordinarily done by the child of normal +faculties.</p> + +<p>In our hasty review of the methods now in use we noted the +inability to approximate this desirable process as a common +difficulty. The facility now ordinarily attained in the +manipulation of the type writer, and the speed said to have been +reached by Professor Bell and a private pupil of his by the +Dalgarno touch alphabet, when we consider the possibility of a less +complex mechanism in the one case and a more systematic grouping of +the alphabet in the other, would lead us to expect a more rapid +means of communication than is ordinarily acquired by dactylology, +speech (by the deaf), or writing. Then the ability to receive the +communication rapidly by the sense of feeling will be far greater. +No part of the body except the point of the tongue is as sensible +to touch as the tips of the fingers and the palm of the hand. +Tactile discrimination is so acute as to be able to interpret to +the brain significant impressions produced in very rapid +succession. Added to this advantage is the greater one of the +absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the +tympanum of the ear. To sum up, then, the advantages of the device +we find--</p> + +<p>First. A more rapid means of communication with the deaf by +syntactic language, admitting of a greater amount of practice +similar to that received through the ear by normal children.</p> + +<p>Second. Ability to receive this rapid communication for a longer +duration and without ocular strain.</p> + +<p>Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender.</p> + +<p>Fourth. In articulation and speech-reading instruction, the +power to assist a class without distracting the attention of the +eye from the vocal organs of the teacher.</p> + +<p>Fifth. Freedom of the right hand of the pupil to make +instantaneous reproduction in writing of the matter being received +through the sense of feeling, thereby opening the way for a +valuable class exercise.</p> + +<p>Sixth. The possible mental stimulus that accompanies the mastery +of a new language, and the consequent ability to receive known +ideas through a new medium.</p> + +<p>Seventh. A fresh variety of class exercises made possible.</p> + +<p>The writer firmly believes in the good that exists in all +methods that are, or are to be; in the interdependence rather than +the independence of all methods; and in all school-room appliances +tending to supplement or expedite the labors of the teacher, +whether they are made of materials delved from the earth or +snatched from the clouds.</p> + +<p>S. TEFFT WALKER,</p> + +<p><i>Superintendent of the Kansas Institution, Olathe, +Kans</i>.</p> + +<hr> +<p><a name="11"></a></p> + +<h2>WATER GAS.</h2> + +<h3>THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON +REDUCING AGENTS.</h3> + +<h3>By B.H. THWAITE.</h3> + +<p>In order to approximately ascertain the relative reducing action +of water gas, carbon monoxide, and superheated steam on iron ore, +the author decided to have carried out the following experiments, +which were conducted by Mr. Carl J. Sandahl, of Stockholm, who also +carried out the analyses. The ore used was from Bilbao, and known +as the Ruby Mine, and was a good average hematite. The carbonaceous +material was the Trimsaran South Wales anthracite, and contained +about 90 per cent. of carbon.</p> + +<p>A small experimental furnace was constructed of the form shown +by illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the +base, and gradually swelling to 2 ft. 9 in. at the top, built +entirely of fireclay bricks. Two refractory tubes, 2 in. square +internally, and the height of the furnace, were used for the double +purpose of producing the gas and reducing the ore.</p> + +<p>The end of the lower tube rested on a fireclay ladle nozzle, and +was properly jointed with fireclay; through this nozzle the steam +or air was supplied to the inside of the refractory tubes. In each +experiment the ore and fuel were raised to the temperature "of from +1,800 to 2,200 deg. Fahr." by means of an external fire of +anthracite. Great care was taken to prevent the contact of the +solid carbonaceous fuel with the ore. In each experiment in which +steam was used, the latter was supplied at a temperature equivalent +to 35 lb. to the square inch.</p> + +<p>The air for producing the carbon monoxide (CO) gas was used at +the temperature of the atmosphere. As near as possible, the same +conditions were obtained in each experiment, and the equivalent +weight of air was sent through the carbon to generate the same +weight of CO as that generated when steam was used for the +production of water gas.</p> + +<p class="ctr"><img src="./illustrations/11a.png" alt=""></p> + +<p><i>First Experiment, Steam (per se)</i>.--Both tubes, A and B, +were filled with ore broken to the size of nuts. The tube, A, was +heated to about 2,000 deg. Fahr., the upper one to about 1,500 +deg.</p> + +<p>NOTE.--In this experiment, part of the steam was dissociated in +passing through the turned-up end of the steam supply pipe, which +became very hot, and the steam would form with the iron the +magnetic oxide (Fe<sub>3</sub>O<sub>4</sub>). The reduction would +doubtless be due to this dissociation. The pieces of ore found on +lowest end of the tube, A, were dark colored and semi-fused; part +of one of these pieces was crushed fine, and tested; see column I. +The remainder of these black pieces was mixed with the rest of the +ore contained in tube, A, and ground and tested; see column II. The +ore in upper tube was all broken up together and tested; see column +III. When finely crushed, the color of No. I. was bluish black; No. +II., a shade darker red; No. III., a little darker than the natural +color of the ore. The analyses gave:</p> + +<pre> +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- +</pre> + +<p><i>Second Experiment, Water Gas</i>.--The tube, A, was filled +with small pieces of anthracite, and heated until all the volatile +matter had been expelled. The tube, B, was then placed in tube, A, +the joint being made with fireclay, and to prevent the steam from +carrying small particles of solid carbon into ore in the upper +tube, the anthracite was divided from the ore by means of a piece +of fine wire gauze. The steam at a pressure of about 35 lb. to the +square inch was passed through the anthracite. The tube, A, was +heated to white heat, the tube, B, at its lower end to bright red, +the top to cherry red.</p> + +<pre> +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +<br> +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ +</pre> + +<p><i>Four Samples were Tested</i>.--I. The bottom layer, 1¼ +in. thick; the color of ore quite black, with small particles of +reduced spongy metallic iron. II. Layer above I., 4¼ in. +thick; the color was also black, but showed a little purple tint. +III. Layer above II., 5 in. thick; purple red color. IV. Layer +above III., ore a red color. The analyses gave:</p> + +<pre> +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- +</pre> + +<p>NOTE.--All the carbon dioxide (CO<sub>2</sub>) occurring in the +ore as calcic carbonate was expelled.</p> + +<p><i>Third Experiment, Carbon monoxide</i> (CO).--The tube A was +filled with anthracite in the manner described for the second +experiment, and heated to drive off the volatile matter, before the +ore was placed in the upper tube, B, and the anthracite was divided +from the ore by means of a piece of fine wire gauze. The lower +tube, A, was heated to the temperature of white heat, the upper +one, B, to a temperature of bright red. I. Layer, 1 in. thick from +the bottom; ore dark brownish colored. II. Layer 4 in. thick above +I.; ore reddish brown. III. Layer 11 in. thick above II.; ore red +color. The analyses gave:</p> + +<pre> +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- +</pre> + +<p>NOTE.--The carbon monoxide (CO) had failed to remove from the +ore the carbon dioxide existing as calcic carbonate. The summary of +experiments in the following table appears to show that the water +gas is a more powerful reducing agent than CO in proportion to the +ratio of as</p> + +<pre> + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 +</pre> + +<p>Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just +now constructing large experimental plant in which water gas will +be used as the reducing agent. This plant would have been at work +before this but for some defects in the valvular arrangements, +which will be entirely removed in the new modifications of the +plant.</p> + +<hr> +<h2>ANTISEPTIC MOUTH WASH.</h2> + +<p>Where an antiseptic mouth wash is needed, Mr. Sewill prescribes +the use of perchloride of mercury in the following form: One grain +of the perchloride and 1 grain of chloride of ammonium to be +dissolved in 1 oz. of eau de Cologne or tincture of lemons, and a +teaspoonful of the solution to be mixed with two-thirds of a +wineglassful of water, making a proportion of about 1 of +perchloride in 5,000 parts.--<i>Chemist and Druggist</i>.</p> + +<hr> +<p><a name="1"></a></p> + +<h2>ANNATTO.</h2> + +<p>[Footnote: Read at an evening meeting of the North British +Branch of the Pharmaceutical Society, January 21.]</p> + +<h3>By WILLIAM LAWSON.</h3> + +<p>The subject which I have the honor to bring shortly before your +notice this evening is one that formed the basis of some +instructive remarks by Dr. Redwood in November, 1855, and also of a +paper by Dr. Hassall, read before the Society in London in January, +1856, which latter gave rise to an animated discussion. The work +detailed below was well in hand when Mr. MacEwan drew my attention +to these and kindly supplied me with the volume containing reports +of them. Unfortunately, they deal principally with the +adulterations, while I was more particularly desirous to learn the +composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. +Within the last few years it was one of the articles in +considerable demand in this part of the country; now it is seldom +inquired for. This, certainly, is not because butter coloring has +ceased to be employed, and hence the reason for regretting that the +percentage of resin was not dealt with in the articles referred to, +so that a comparison could have been made between the commercial +annatto of that period and that which exists now. In case some may +not be in possession of literature bearing on it--which, by the +way, is very meager--it may not be out of place to quote some short +details as to its source, the processes for obtaining it, the +composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has +more interest for the country than for the town druggist, still, I +trust it will have points of interest for both.</p> + +<p>Annatto is the coloring matter derived from the seeds of an +evergreen plant, <i>Bixa Orellana</i>, which grows in the East and +West Indian Islands and South America, in the latter of which it is +principally prepared. Two kinds are imported, Spanish annatto, made +in Brazil, and flag or French, made mostly in Cayenne. These differ +considerably in characters and properties, the latter having a +disagreeable putrescent odor, while the Spanish is rather agreeable +when fresh and good. It is, however, inferior to the flag as a +coloring or dyeing agent. The seeds from which the substance is +obtained are red on the outside, and two methods are followed in +order to obtain it. One is to rub or wash off the coloring matter +with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to +bruise the seeds, mix them with water, and allow fermentation to +set in, during which the coloring matter collects at the bottom, +from which it is subsequently removed and brought to the proper +consistence by spontaneous evaporation. These particulars, culled +from Dr. Redwood's remarks, may suffice to show its source and the +methods for obtaining it.</p> + +<p>Dr. John gives the following as the composition of the pulp +surrounding the seeds: Coloring resinous matter, 28; vegetable +gluten, 26.5; ligneous fiber, 20; coloring, 20; extractive matter, +4; and a trace of spicy and acid matter.</p> + +<p>It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as +well as to preserve it, differs considerably from this; and though +it may not be true, as some hint, that manufacturing in this +industry is simply a term synonymous with adulterating, yet results +will afterward be given tending to show that there are articles in +the market which have little real claim to the title. I tried, but +failed, to procure a sample of raw material on which to work, with +a view to learn something of its characters and properties in this +state, and thus be able to contrast it with the manufactured or +commercial article. The best thing to do in the circumstances, I +thought, was to operate on the highest priced sample at disposal, +and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the +usual way, I believe--was a more troublesome operation than it +appeared to be, as the following experiment will show: One hundred +grains of No. 8 were taken, dried thoroughly, reduced to fine +powder, and introduced into a flask containing 4 ounces of alcohol +in the form of methylated spirit, boiled for an hour--the flask +during the operation being attached to an inverted +condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated +with diminishing quantities until in all 14 ounces had been used +before the alcoholic solution ceased to turn blue on the addition +to it of strong sulphuric acid, or failed to give a brownish +precipitate with stannous chloride. As the sample contained a +considerable quantity of potassium carbonate, in which the resin is +soluble, it was thought that by neutralizing this it might render +the resin more easy of extraction. This was found to be so, but it +was accompanied by such a mass of extractive as made it in the long +run more troublesome, and hence it was abandoned. Thinking the +spirit employed might be too weak, an experiment with commercial +absolute alcohol was carried out as follows: One hundred grains of +a red sample, No. 4, were thoroughly dried, powdered finely, and +boiled in 2 ounces of the alcohol, filtered, and the residue +treated with half an ounce more. This required to be repeated with +fresh half ounces of the alcohol until in all 7½ were used; +the time occupied from first to last being almost three hours. This +was considered unsatisfactory, besides being very expensive, and so +it, also, was set aside, and a series of experiments with +methylated spirit alone was set in hand. The results showed that +the easiest and most satisfactory way was to take 100 grains (this +amount being preferred, as it reduces error to the minimum), dry +thoroughly, powder finely, and macerate with frequent agitation for +twenty-four hours in a few ounces of spirit, then to boil in this +spirit for a short time, filter, and repeat the boiling with a +fresh ounce or so; this, as a rule, sufficing to completely exhaust +it of its resin. Wynter Blyth says that the red resin, or bixin, is +soluble in 25 parts of hot alcohol. It appears from these +experiments that much more is required to dissolve it out of +commercial annatto.</p> + +<p>The full process followed consisted in determining the moisture +by drying 100 grains at 212° F. till constant, and taking this +dried portion for estimation of the resin in the way just stated. +The alcoholic extract was evaporated to dryness over a water-bath, +the residue dissolved in solution of sodium carbonate, and the +resin precipitated by dilute sulphuric acid (these reagents being +chosen as the best after numerous trials with others), added in the +slightest possible excess. The resin was collected on a tared +double filter paper, washed with distilled water until the washings +were entirely colorless, dried and weighed.</p> + +<p>The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of +them.</p> + +<p>The results are as follows:</p> + +<pre> + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 +</pre> + +<p>The first six are the ordinary red rolls, with the exception of +No. 4, which is a red mass, the only one of this class direct from +the manufacturers. The remainder are brown cakes, all except No. 7 +being from the manufacturers direct. The ash of the first two was +largely common salt; that of No. 3 contained, besides this, iron in +some quantity. No. 4 is unique in many respects. It was of a bright +red color, and possessed a not disagreeable odor. It contained the +largest percentage of moisture and the lowest of ash; had, +comparatively, a large amount of coloring matter; was one of the +cheapest, and in the course of some dairy trials, carried out by an +intelligent farmer, was pronounced to be the best suited for +coloring butter. So far as my experience goes, it was a sample of +the best commercial excellence, though I fear the mass of water +present and the absence of preserving substances will assist in its +speedy decay. Were such an article easily procured in the usual way +of business, there would not be much to complain of, but it must +not be forgotten that it was got direct from the manufacturers--a +somewhat suggestive fact when the composition of some other samples +is taken into account. No. 5 emitted a disagreeable odor during +ignition. The soluble portion of the ash was mostly common salt, +and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter +gave rise to disagreeable reflections. It was wrapped in a paper +saturated with a strongly smelling linseed oil. When it was boiled +in water and broken up, hairs, among other things, were observed +floating about. It contained some iron. The first cake, No. 7, gave +off during ignition an agreeable odor resembling some of the finer +tobaccos, and this is characteristic more or less of all the cakes. +The ash weighed 52 per cent., the soluble part of which, 18.5, was +mostly potassium carbonate, with some chlorides and sulphates; the +insoluble, mostly chalk with iron and alumina. No. 8--highest +priced of all--had in the mass an odor which I can compare to +nothing else than a well rotted farmyard manure. Twenty parts of +the ash were soluble and largely potassium carbonate, the insoluble +being iron for the most part. The mineral portions of Nos. 9 and 10 +closely resemble No. 7.</p> + +<p>On looking over the results, it is found that the red rolls +contained starchy matters in abundance (in No. 4 the starch was to +a large extent replaced by water), and an ash, mostly sodium +chloride, introduced no doubt to assist in its preservation as well +as to increase the color of the resin--a well known action of salt +on vegetable reds. The cakes, which are mostly used for cheese +coloring, I believe, all appeared to contain turmeric, for they +gave a more or less distinct reaction with the boric acid test, and +all except No. 8 contained large quantities of chalk. These results +in reference to extractive, etc., reveal nothing that has not been +known before. Wynter Blyth, who gives the only analyses of annatto +I have been able to find, states that the composition of a fair +commercial sample (which I take to mean the raw article) examined +by him was as follows: water, 24.2; resin, 28.8; ash, 22.5; and +extractive, 24.5; and that of an adulterated (which I take to mean +a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. +27.3. If this be correct, it appears that the articles at present +in the market, or at least those which have come in my way, have +been wretched imitations of the genuine thing, and should, instead +of being called adulterated annatto, be called something else +adulterated, but not seriously, with annatto. I have it on the +authority of the farmer previously referred to, that ¼ of an +ounce of No. 4 is amply sufficient to impart the desired cowslip +tint to no less than 60 lb. of butter. When so little is actually +required, it does not seem of very serious importance whether the +adulterant or preservative be flour, chalk, or water, but it is +exasperating in a very high degree to have such compounds as Nos. 3 +and 6 palmed off as decent things when even Nos. 1, 2, and 5 have +been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may +be induced to examine the annatto taken into stock more closely +than I was taught to do, and had been in the habit of doing, +namely, to see if it had a good consistence and an odor resembling +black sugar, for if so, the quality was above suspicion.</p> + +<hr> +<p><a name="12"></a></p> + +<h2>JAPANESE RICE WINE AND SOJA SAUCE.</h2> + +<p>Professor P. Cohn has recently described the mode in which he +has manufactured the Japanese sake or rice wine in the laboratory. +The material used was "Tane Kosi," i.e., grains of rice coated with +the mycelium, conidiophores, and greenish yellow chains of conidia +of <i>Aspergillus Oryzoe</i>. The fermentation is caused by the +mycelium of this fungus before the development of the +fructification. The rice is first exposed to moist air so as to +change the starch into paste, and then mixed with grains of the +"Tane Kosi." The whole mass of rice becomes in a short time +permeated by the soft white shining mycelium, which imparts to it +the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two +or three days, and then subjected to alcoholic fermentation from +the <i>Saccharomyces</i>, which is always present in the rice, but +which has nothing to do with the <i>Aspergillus</i>. The +fermentation is completed in two or three weeks, and the golden +yellow, sherry-like sake is poured off. The sample manufactured +contained 13.9 per cent. of alcohol. Chemical investigation showed +that the <i>Aspergillus</i> mycelium transforms the starch into +glucose, and thus plays the part of a diastase.</p> + +<p>Another substance produced from the <i>Aspergillus</i> rice is +the soja sauce. The soja leaves, which contain little starch, but a +great deal of oil and casein, are boiled, mixed with roasted +barley, and then with the greenish yellow conidia powder of the +<i>Aspergillus</i>. After the mycelium has fructified, the mass is +treated with a solution of sodium chloride, which kills the +<i>Aspergillus</i>, another fungus, of the nature of a +<i>Chalaza</i>, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce +then separates.</p> + +<hr> +<p><a name="2"></a></p> + +<h2>ALUMINUM.</h2> + +<p>[Footnote: Annual address delivered by President J.A. Price +before the meeting of the Scranton Board of Trade, Monday, January +18, 1886.]</p> + +<h3>By J.A. PRICE.</h3> + +<p>Iron is the basis of our civilization. Its supremacy and power +it is impossible to overestimate; it enters every avenue of +development, and it may be set down as the prime factor in the +world's progress. Its utility and its universality are hand in +hand, whether in the magnificent iron steamship of the ocean, the +network of iron rail upon land, the electric gossamer of the air, +or in the most insignificant articles of building, of clothing, and +of convenience. Without it, we should have miserably failed to +reach our present exalted station, and the earth would scarcely +maintain its present population; it is indeed the substance of +substances. It is the Archimedean lever by which the great human +world has been raised. Should it for a moment forget its cunning +and lose its power, earthquake shocks or the wreck of matter could +not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that +it must give way to a metal that has still greater proportions and +vaster possibilities. Strange and startling as may seem the +assertion, yet I believe it nevertheless to be true that we are +approaching the period, if not already standing upon the threshold +of the day, when this magical element will be radically supplanted, +and when this valuable mineral will be as completely superseded as +the stone of the aborigines. With all its apparent potency, it has +its evident weaknesses; moisture is everywhere at war with it, +gases and temperature destroy its fiber and its life, continued +blows or motion crystallize and rob it of its strength, and acids +will devour it in a night. If it be possible to eliminate all, or +even one or more, of these qualities of weakness in any metal, +still preserving both quantity and quality, that metal will be the +metal of the future.</p> + +<p>The coming metal, then, to which our reference is made is +aluminum, the most abundant metal in the earth's crust. Of all +substances, oxygen is the most abundant, constituting about +one-half; after oxygen comes silicon, constituting about +one-fourth, with aluminum third in all the list of substances of +the composition. Leaving out of consideration the constituents of +the earth's center, whether they be molten or gaseous, more or less +dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we +find that aluminum is beyond question the most abundant and the +most useful of all metallic substances.</p> + +<p>It is the metallic base of mica, feldspar, slate, and clay. +Professor Dana says: "Nearly all the rocks except limestones and +many sandstones are literally ore-beds of the metal aluminum." It +appears in the gem, assuming a blue in the sapphire, green in the +emerald, yellow in the topaz, red in the ruby, brown in the emery, +and so on to the white, gray, blue, and black of the slates and +clays. It has been dubbed "clay metal" and "silver made from clay;" +also when mixed with any considerable quantity of carbon becoming a +grayish or bluish black "alum slate."</p> + +<p>This metal in color is white and next in luster to silver. It +has never been found in a pure state, but is known to exist in +combination with nearly two hundred different minerals. Corundum +and pure emery are ores that are very rich in aluminum, containing +about fifty-four per cent. The specific gravity is but two and +one-half times that of water; it is lighter than glass or as light +as chalk, being only one-third the weight of iron and one-fourth +the weight of silver; it is as malleable as gold, tenacious as +iron, and harder than steel, being next the diamond. Thus it is +capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. +Its variety of transformations is something wonderful. Meeting +iron, or even iron at its best in the form of steel, in the same +field, it easily vanquishes it at every point. It melts at 1,300 +degrees F., or at least 600 degrees below the melting point of +iron, and it neither oxidizes in the atmosphere nor tarnishes in +contact with gases. The enumeration of the properties of aluminum +is as enchanting as the scenes of a fairy tale.</p> + +<p>Before proceeding further with this new wonder of science, which +is already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French +chemist Lavoisier, a very magician in the science, groping in the +dark of the last century, evolved the chemical theory of +combustion--the existence of a "highly respirable gas," oxygen, and +the presence of metallic bases in earths and alkalies. With the +latter subject we have only to do at the present moment. The +metallic base was predicted, yet not identified. The French +Revolution swept this genius from the earth in 1794, and darkness +closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon +the metallic base of certain earths, but the reflection was so +feeble that the great secret was never revealed. Then a little +later the Swedish Berzelius and the Danish Oersted, confident in +the prediction of Lavoisier and of Davy, went in search of the +mysterious stranger with the aggressive electric current, but as +yet to no purpose. It was reserved to the distinguished German +Wohler, in 1827, to complete the work of the past fifty years of +struggle and finally produce the minute white globule of the pure +metal from a mixture of the chloride of aluminum and sodium, and at +last the secret is revealed--the first step was taken. It took +twenty years of labor to revolve the mere discovery into the +production of the aluminum bead in 1846, and yet with this first +step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come.</p> + +<p>Returning again to France some time during the years between +1854 and 1858, and under the patronage of the Emperor Napoleon +III., we behold Deville at last forcing Nature to yield and give up +this precious quality as a manufactured product. Rose, of Berlin, +and Gerhard, in England, pressing hard upon the heels of the +Frenchman, make permanent the new product in the market at +thirty-two dollars per pound. The despair of three-quarters of a +century of toilsome pursuit has been broken, and the future of the +metal has been established.</p> + +<p>The art of obtaining the metal since the period under +consideration has progressed steadily by one process after another, +constantly increasing in powers of productivity and reducing the +cost. These arts are intensely interesting to the student, but must +be denied more than a reference at this time. The price of the +metal may be said to have come within the reach of the +manufacturing arts already.</p> + +<p>A present glance at the uses and possibilities of this wonderful +metal, its application and its varying quality, may not be out of +place. Its alloys are very numerous and always satisfactory; with +iron, producing a comparative rust proof; with copper, the +beautiful golden bronze, and so on, embracing the entire list of +articles of usefulness as well as works of art, jewelry, and +scientific instruments.</p> + +<p>Its capacity to resist oxidation or rust fits it most eminently +for all household and cooking utensils, while its color transforms +the dark visaged, disagreeable array of pots, pans, and kitchen +implements into things of comparative beauty. As a metal it +surpasses copper, brass, and tin in being tasteless and odorless, +besides being stronger than either.</p> + +<p>It has, as we have seen, bulk without weight, and consequently +may be available in construction of furniture and house fittings, +as well in the multitudinous requirements of architecture. The +building art will experience a rapid and radical change when this +material enters as a component material, for there will be +possibilities such as are now undreamed of in the erection of +homes, public buildings, memorial structures, etc. etc., for in +this metal we have the strength, durability, and the color to give +all the variety that genius may dictate.</p> + +<p>And when we take a still further survey of the vast field that +is opening before us, we find in the strength without size a most +desirable assistant in all the avenues of locomotion. It is the +ideal metal for railway traffic, for carriages and wagons. The +steamships of the ocean of equal size will double their cargo and +increase the speed of the present greyhounds of the sea, making six +days from shore to shore seem indeed an old time calculation and +accomplishment. A thinner as well as a lighter plate; a smaller as +well as a stronger engine; a larger as well as a less hazardous +propeller; and a natural condition of resistance to the action of +the elements; will make travel by water a forcible rival to the +speed attained upon land, and bring all the distant countries in +contact with our civilization, to the profit of all. This metal is +destined to annihilate space even beyond the dream of philosopher +or poet.</p> + +<p>The tensile strength of this material is something equally +wonderful, when wire drawn reaches as high as 128,000 pounds, and +under other conditions reaches nearly if not quite 100,000 pounds +to the square inch. The requirements of the British and German +governments in the best wrought steel guns reach only a standard of +70,000 pounds to the square inch. Bridges may be constructed that +shall be lighter than wooden ones and of greater strength than +wrought steel and entirely free from corrosion. The time is not +distant when the modern wonder of the Brooklyn span will seem a +toy.</p> + +<p>It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube.</p> + +<p>The resistance to corrosion evidently fits this metal for +railway sleepers to take the place of the decaying wooden ties. In +this metal the sleeper may be made as soft and yielding as lead, +while the rail may be harder and tougher than steel, thus at once +forming the necessary cushion and the avoidance of jar and noise, +at the same time contributing to additional security in virtue of a +stronger rail.</p> + +<p>In conductivity this metal is only exceeded by copper, having +many times that of iron. Thus in telegraphy there are renewed +prospects in the supplanting of the galvanized iron +wire--lightness, strength, and durability. When applied to the +generation of steam, this material will enable us to carry higher +pressure at a reduced cost and increased safety, as this will be +accomplished by the thinner plate, the greater conductivity of +heat, and the better fiber.</p> + +<p>It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in +the mechanic art lies dormant--the size of the machine may be +reduced, the speed and the power increased, realizing the +conception of two things better done than one before. It is one of +man's creative acts.</p> + +<p>From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, +Paris, asserts that 120,000 blows will exhaust the usefulness of +the cushion of the stamp machine, and this number of blows is given +in a day; and that when a cushion of aluminum bronze was +substituted, it was unaffected after months of use.</p> + +<p>If we have found a metal that possesses both tensile strength +and resistance to compression; malleability and ductility--the +quality of hardening, softening, and toughening by tempering; +adaptability to casting, rolling, or forging; susceptibility to +luster and finish; of complete homogeneous character and unusually +resistant to destructive agents--mankind will certainly leave the +present accomplishments as belonging to an effete past, and, as it +were, start anew in a career of greater prospects.</p> + +<p>This important material is to be found largely in nearly all the +rocks, or as Prof. Dana has said, "Nearly all rocks are ore-beds of +the metal." It is in every clay bank. It is particularly abundant +in the coal measures and is incidental to the shales or slates and +clays that underlie the coal. This under clay of the coal stratum +was in all probability the soil out of which grew the vegetation of +the coal deposits. It is a compound of aluminum and other matter, +and, when mixed with carbon and transformed by the processes of +geologic action, it becomes the shale rock which we know and which +we discard as worthless slate. And it is barely possible that we +have been and are still carting to the refuse pile an article more +valuable than the so greatly lauded coal waste or the merchantable +coal itself. We have seen that the best alumina ore contains only +fifty-four per cent. of metal.</p> + +<p>The following prepared table has been furnished by the courtesy +and kindness of Mr. Alex. H. Sherred, of Scranton.</p> + +<pre> + ALUMINA. +<br> +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 +</pre> + +<p>It will be seen that the black clay, shale, or slate, has a +constituent of aluminum of from 15.93 per cent., the lowest, to +32.60 per cent., the highest. Under every stratum of coal, and +frequently mixed with it, are these under deposits that are rich in +the metal. When exposed to the atmosphere, these shales yield a +small deposit of alum. In the manufacture of alum near Glasgow the +shale and slate clay from the old coal pits constitute the material +used, and in France alum is manufactured directly from the +clay.</p> + +<p>Sufficient has been advanced to warrant the additional assertion +that we are here everywhere surrounded by this incomparable +mineral, that it is brought to the surface from its deposits deep +in the earth by the natural process in mining, and is only exceeded +in quantity by the coal itself. Taking a columnar section of our +coal field, and computing the thickness of each shale stratum, we +have from twenty-five to sixty feet in thickness of this +metal-bearing substance, which averages over twenty-five per cent. +of the whole in quantity in metal.</p> + +<p>It is readily apparent that the only task now before us is the +reduction of the ore and the extraction of the metal. Can this be +done? We answer, it has been done. The egg has stood on end--the +new world has been sighted. All that now remains is to repeat the +operation and extend the process. Cheap aluminum will revolutionize +industry, travel, comfort, and indulgence, transforming the present +into an even greater civilization. Let us see.</p> + +<p>We have seen the discovery of the mere chemical existence of the +metal, we have stood by the birth of the first white globule or +bead by Wohler, in 1846, and witnesssed its introduction as a +manufactured product in 1855, since which time, by the alteration +and cheapening of one process after another, it has fallen in price +from thirty-two dollars per pound in 1855 to fifteen dollars per +pound in 1885. Thirty years of persistent labor at smelting have +increased the quantity over a thousandfold and reduced the cost +upward of fifty per cent.</p> + +<p>All these processes involve the application of heat--a mere +question of the appliances. The electric currents of Berzelius and +Oersted, the crucible of Wohler, the closed furnaces and the +hydrogen gas of the French manufacturers and the Bessemer converter +apparatus of Thompson, all indicate one direction. This metal can +be made to abandon its bed in the earth and the rock at the will of +man. During the past year, the Messrs. Cowles, of Cleveland, by +their electric smelting process, claim to have made it possible to +reduce the price of the metal to below four dollars per pound; and +there is now erecting at Lockport, New York, a plant involving one +million of capital for the purpose.</p> + +<p>Turning from the employment of the expensive reducing agents to +the simple and sole application of heat, we are unwilling to +believe that we do not here possess in eminence both the mineral +and the medium of its reduction. Whether the electric or the +reverberatory or the converter furnace system be employed, it is +surely possible to produce the result.</p> + +<p>To enter into consideration of the details of these +constructions would involve more time than is permitted us on this +occasion. They are very interesting. We come again naturally to the +limitless consideration of powdered fuel, concerning which certain +conclusions have been reached. In the dissociation of water into +its hydrogen and oxygen, with the mingled carbon in a powdered +state, we undoubtedly possess the elements of combustion that are +unexcelled on earth, a heat-producing combination that in both +activity and power leaves little to be desired this side of the +production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and +furnaces.</p> + +<p>In the hope of stimulating thought to this infinite question of +proper fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope +this Board will not grudgingly devote to the subject, but which is +impossible at present. Do not forget that there is no single spot +on the face of the globe where nature has lavished more freely her +choicest gifts. Let us be active in the pursuit of the treasure and +grateful for the distinguished consideration.</p> + +<hr> +<p><a name="19"></a></p> + +<h2>THE ORIGIN OF METEORITES.</h2> + +<p>On January 9, Professor Dewar delivered the sixth and last of +his series of lectures at the Royal Institution on "The Story of a +Meteorite." [For the preceding lectures, see SUPPLEMENTS 529 and +580.] He said that cosmic dust is found on Arctic snows and upon +the bottom of the ocean; all over the world, in fact, at some time +or other, there has been a large deposit of this meteoric dust, +containing little round nodules found also in meteorites. In +Greenland some time ago numbers of what were supposed to be +meteoric stones were found; they contained iron, and this iron, on +being analyzed at Copenhagen, was found to be rich in nickel. The +Esquimaux once made knives from iron containing nickel; and as any +such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited +the basaltic coast in Greenland from which some of the supposed +meteoric stones had been brought, and in the middle of the rock +large nodules were found composed of iron and nickel; it, +therefore, became evident that the earth might produce masses not +unlike such as come to us as meteorites. The lecturer here +exhibited a section of the Greenland rock containing the iron, and +nickel alloy, mixed with stony crystals, and its resemblance to a +section of a meteorite was obvious. It was 2½ times denser +than water, yet the whole earth is 5½ times denser than +water, so that if we could go deep enough, it is not improbable +that our own globe might be found to contain something like +meteoric iron. He then called attention to the following +tables:</p> + +<pre> + <i>Elementary Substances found in Meteorites</i>. +<br> + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. +</pre> + +<p><i>Density of Meteorites</i>.</p> + +<pre> + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 +</pre> + +<p><i>Interior of the Earth</i></p> + +<pre> + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 +</pre> + +<p class="ctr"><img src="./illustrations/13a.png" alt=""></p> + +<p>Twice a year, said Professor Dewar, what are called "falling +stars" maybe plentifully seen; the times of their appearance are in +August and November. Although thousands upon thousands of such +small meteors have passed through our atmosphere, there is no +distinct record of one having ever fallen to the earth during these +annual displays. One was said to have fallen recently at Naples, +but on investigation it turned out to be a myth. These annual +meteors in the upper air are supposed to be only small ones, and to +be dissipated into dust and vapor at the time of their sudden +heating; so numerous are they that 40,000 have been counted in one +evening, and an exceptionally great display comes about once in +33¼ years. The inference from their periodicity is, that +they are small bodies moving round the sun in orbits of their own, +and that whenever the earth crosses their orbits, thereby getting +into their path, a splendid display of meteors results. A second +display, a year later, usually follows the exceptionally great +display just mentioned, consequently the train of meteors is of +great length. Some of these meteors just enter the atmosphere of +the earth, then pass out again forever, with their direction of +motion altered by the influence of the attraction of the earth. He +here called attention to the accompanying diagram of the orbits of +meteors.</p> + +<p>The lecturer next invited attention to a hollow globe of linen +or some light material; it was about 2 ft. or 2 ft. 6 in. in +diameter, and contained hidden within it the great electro-magnet, +weighing 2 cwt., so often used by Faraday in his experiments. He +also exhibited a ball made partly of thin iron; the globe +represented the earth, for the purposes of the experiment, and the +ball a meteorite of somewhat large relative size. The ball was then +discharged at the globe from a little catapult; sometimes the globe +attracted the ball to its surface, and held it there, sometimes it +missed it, but altered its curve of motion through the air. So was +it, said the lecturer, with meteorites when they neared the earth. +Photographs from drawings, by Professor A. Herschel, of the paths +of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, +is a proof that their motions are parallel to each other; the +parallel lines seem to draw to a point at the greatest distance, +for the same reason that the rails of a straight line of railway +seem to come from a distant central point. The most interesting +thing about the path of a company of meteors is, that a comet is +known to move in the same orbit; the comet heads the procession, +the meteors follow, and they are therefore, in all probability, +parts of comets, although everything about these difficult matters +cannot as yet be entirely explained; enough, however, is known to +give foundation for the assumption that meteorites and comets are +not very dissimilar.</p> + +<p>The light of a meteorite is not seen until it enters the +atmosphere of the earth, but falling meteorites can be vaporized by +electricity, and the light emitted by their constituents be then +examined with the spectroscope. The light of comets can be directly +examined, and it reveals the presence in those bodies of sodium, +carbon, and a few other well-known substances. He would put a piece +of meteorite in the electric arc to see what light it would give; +he had never tried the experiment before. The lights of the theater +were then turned down, and the discourse was continued in darkness; +among the most prominent lines visible in the spectrum of the +meteorite, Professor Dewar specified magnesium, sodium, and +lithium. "Where do meteorites come from?" said the lecturer. It +might be, he continued, that they were portions of exploded +planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular +hypothesis that at some long past time our sun and all his planets +existed but as a volume of gas, which in contracting and cooling +formed a hot volume of rotating liquid, and that as this further +contracted and cooled, the planets, and moons, and planetary rings +fell off from it and gradually solidified, the sun being left as +the solitary comparatively uncooled portion of the original nebula. +In partial illustration of this, he caused a little globe of oil, +suspended in an aqueous liquid of nearly its own specific gravity, +to rotate, and as it rotated it was seen, by means of its magnified +image upon the screen, to throw off from its outer circumference +rings and little globes.</p> + +<hr> +<p><a name="17"></a></p> + +<h2>CANDELABRA CACTUS AND CALIFORNIA WOODPECKER.</h2> + +<h3>By C.F. HOLDER.</h3> + +<p>One of the most picturesque objects that meet the eye of the +traveler over the great plains of the southern portion of +California and New Mexico is the candelabra cactus. Systematically +it belongs to the Cereus family, in which the notable +Night-blooming Cereus also is naturally included. In tropical or +semi-tropical countries these plants thrive, and grow to enormous +size. For example, the Cereus that bears those great flowers, and +blooms at night, exhaling powerful perfume, as we see them in +hothouses in our cold climate, are even in the semi-tropical region +of Key West, on the Florida Reef, seen to grow enormously in +length.</p> + +<p class="ctr"><a href="./illustrations/14a.png"><img src= +"./illustrations/14a_th.jpg" alt= +"THE CANDELABRA CACTUS--CEREUS GIGANTEUS."></a></p> + +<p class="ctr">THE CANDELABRA CACTUS--CEREUS GIGANTEUS.</p> + +<p>We cultivated several species of the more interesting forms +during a residence on the reef. Our brick house, two stories in +height, was entirely covered on a broad gable end, the branches +more than gaining the top. There is a regular monthly growth, and +this is indicated by a joint between each two lengths. Should the +stalk be allowed to grow without support, it will continue growing +without division, and exhibit stalks five or six feet in length, +when they droop, and fall upon the ground.</p> + +<p>Where there is a convenient resting place on which it can spread +out and attach itself, the stalk throws out feelers and rootlets, +which fasten securely to the wall or brickwork; then, this being a +normal growth, there is a separation at intervals of about a foot. +That is, the stalk grows in one month about twelve inches, and if +it has support, the middle woody stalk continues to grow about an +inch further, but has no green, succulent portion, in fact, looks +like a stem; then the other monthly growth takes place, and ends +with a stem, and so on indefinitely. Our house was entirely covered +by the stems of such a plant, and the flowers were gorgeous in the +extreme. The perfume, however, was so potent that it became a +nuisance. Such is the Night-blooming Cereus in the warm climates, +and similarly the Candelabra Cereus grows in stalks, but +architecturally erect, fluted like columns. The flowers are large, +and resemble those of the night-blooming variety. Some columns +remain single, and are amazingly artificial appearing; others throw +off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being +clusters of side shoots, the latter putting out from the trunk +regularly, and standing up parallel to each other. The enormous +size these attain is well shown in the picture.</p> + +<p>Whenever the great stalks of these cacti die, the succulent +portion is dried, and nothing is left but the woody fiber. They are +hollow in places, and easily penetrated. A species of woodpecker, +<i>Melanerpes formicivorus</i>, is found to have adopted the use of +these dry stalks for storing the winter's stock of provisions. +There are several round apertures seen on the stems in the +pictures, which were pecked by this bird. This species of +woodpecker is about the size of our common robin or migratory +thrush, and has a bill stout and sharp. The holes are pecked for +the purpose of storing away acorns or other nuts; they are just +large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts +are so numerous, the stalk has the appearance of being studded with +bullets. This appearance is more pronounced in cases where the dead +trunk of an oak is used. There are some specimens of the latter now +owned by the American Museum of Natural History, which were +originally sent to the Centennial Exhibition at Philadelphia. They +were placed in the department contributed by the Pacific Railroad +Company, and at that time were regarded as some of the wonders of +that newly explored region through which the railroad was then +penetrating. Some portions of the surface of these logs are nearly +entirely occupied by the holes with acorns in them. The acorns are +driven in very tightly in these examples; much more so than in the +cactus plants, as the oak is nearly round, and the holes were +pecked in solid though dead wood. One of the most remarkable +circumstances connected with this habit of the woodpecker is the +length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to +make a journey of sixty miles to accomplish the storing of one +acorn. At first it seemed strange that a bird should spend so much +labor to place those bits of food, and so far away. De Saussure, a +Swiss naturalist, published in the <i>Bibliotheque Universelle</i>, +of Geneva, entertaining accounts of the Mexican Colaptes, a variety +of the familiar "high hold," or golden winged woodpecker. They were +seen to store acorns in the dead stalks of the maguey (<i>Agave +Americana</i>). Sumichrast, who accompanied him to Central America, +records the same facts. These travelers saw great numbers of the +woodpeckers in a region on the slope of a range of volcanic +mountains. There was little else of vegetation than the +<i>Agave</i>, whose barren, dead stems were studded with acorns +placed there by the woodpeckers.</p> + +<p>The maguey throws up a stalk about fifteen feet in height +yearly, which, after flowering, grows stalky and brittle, and +remains an unsightly thing. The interior is pithy, but after the +death of the stalk the pith contracts, and leaves the greater +portion of the interior hollow, as we have seen in the case of the +cactus branches. How the birds found that these stalks were hollow +is a problem not yet solved, but, nevertheless, they take the +trouble to peck away at the hard bark, and once penetrated, they +commence to fill the interior; when one space is full, the bird +pecks a little higher up, and so continues.</p> + +<p>Dr. Heerman, of California, describes the California +<i>Melanerpes</i> as one of the most abundant of the woodpeckers; +and remarks that it catches insects on the wing like a flycatcher. +It is well determined that it also eats the acorns that it takes so +much pains to transport.</p> + +<p class="ctr"><img src="./illustrations/14b.png" alt= +"FLOWER OF CEREUS GIGANTEUS."></p> + +<p class="ctr">FLOWER OF CEREUS GIGANTEUS.</p> + +<p>It seems that these birds also store the pine trees, as well as +the oaks. It is not quite apparent why these birds exhibit such +variation in habits; they at times select the more solid trees, +where the storing cannot go on without each nut is separately set +in a hole of its own. There seems an instinct prompting them to do +this work, though there may not be any of the nuts touched again by +the birds. Curiously enough, there are many instances of the birds +placing pebbles instead of nuts in holes they have purposely pecked +for them. Serious trouble has been experienced by these pebbles +suddenly coming in contact with the saw of the mill through which +the tree is running. The stone having been placed in a living tree, +as is often the case, its exterior had been lost to sight during +growth.</p> + +<p>Some doubt has been entertained about the purpose of the bird in +storing the nuts in this manner. De Saussure tells us he has +witnessed the birds eating the acorns after they had been placed in +holes in trees, and expresses his conviction that the insignificant +grub which is only seen in a small proportion of nuts is not the +food they are in search of.</p> + +<p>C.W. Plass, Esq., of Napa City, California, had an interesting +example of the habits of the California <i>Melanerpes</i> displayed +in his own house. The birds had deposited numbers of acorns in the +gable end. A considerable number of shells were found dropped +underneath the eaves, while some were found in place under the +gable, and these were perfect, having no grubs in them.</p> + +<p>The picture shows a very common scene in New Mexico. The +columns, straight and angular, are often sixty feet in height. It +is called torch cactus in some places. There are many varieties, +and as many different shapes. Some lie on the ground; others, +attached to trunks of trees as parasites, hang from branches like +great serpents; but none is so majestic as the species called +systematically <i>Cereus giganteus</i>, most appropriately. The +species growing pretty abundantly on the island of Key West is +called candle cactus. It reaches some ten or twelve feet, and is +about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a +pretty, rather picturesque feature in the otherwise barren +undergrowth of shrubbery and small trees. Accompanied by a few +flowering cocoa palms, the view is not unpleasing. The fiber of +these plants is utilized in some coarse manufactures. The maguey, +or Agave, is used in the manufacture of fine roping. Manila hemp is +made from a species. The species whose dried stalks are used by the +woodpeckers for their winter storage was cultivated at Key West, +Florida, during several years before 1858. Extensive fields of the +Agave stood unappropriated at that period. Considerable funds were +dissipated on this venture. Extensive works were established, and +much confidence was entertained that the scheme would prove a +paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their +long stalks, stand now, increasing every year, until a portion of +the island is overrun with them.</p> + +<h3>CEREUS GIGANTEUS.</h3> + +<p>This wonderful cactus, its colossal proportions, and weird, yet +grand, appearance in the rocky regions of Mexico and California, +where it is found in abundance, have been made known to us only +through books of travel, no large plants of it having as yet +appeared in cultivation in this country. It is questionable if ever +the natural desire to see such a vegetable curiosity represented by +a large specimen in gardens like Kew can be realized, owing to the +difficulty of importing large stems in a living condition; and even +if successfully brought here, they survive only a very short time. +To grow young plants to a large size seems equally beyond our +power, as plants 6 inches high and carefully managed are quite ten +years old. When young, the stem is globose, afterward becoming +club-shaped or cylindrical. It flowers at the height of 12 feet, +but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of +an immense candelabrum, the base of the stem being as thick as a +man's body. The flower, of which a figure is given here, is about 5 +inches long and wide, the petals cream colored, the sepals greenish +white. Large clusters of flowers are developed together near the +top of the stem. A richly colored edible fruit like a large fig +succeeds each flower, and this is gathered by the natives and used +as food under the name of saguarro. A specimen of this cactus 3 +feet high may be seen in the succulent house at Kew.--<i>B., The +Garden</i>.</p> + +<hr> +<p><a name="18"></a></p> + +<h2>HOW PLANTS ARE REPRODUCED.</h2> + +<p>[Footnote: Read at a meeting of the Chemists' Assistants' +Association. December 16, 1885.]</p> + +<h3>By C.E. STUART, B.Sc.</h3> + +<p>In two previous papers read before this Association I have tried +to condense into as small a space as I could the processes of the +nutrition and of the growth of plants; in the present paper I want +to set before you the broad lines of the methods by which plants +are reproduced.</p> + +<p>Although in the great trees of the conifers and the dicotyledons +we have apparently provision for growth for any number of years, or +even centuries, yet accident or decay, or one of the many ills that +plants are heirs to, will sooner or later put an end to the life of +every individual plant.</p> + +<p>Hence the most important act of a plant--not for itself perhaps, +but for its race--is the act by which it, as we say, "reproduces +itself," that is, the act which results in the giving of life to a +second individual of the same form, structure, and nature as the +original plant.</p> + +<p>The methods by which it is secured that the second generation of +the plant shall be as well or even better fitted for the struggle +of life than the parent generation are so numerous and complicated +that I cannot in this paper do more than allude to them; they are +most completely seen in cross fertilization, and the adaptation of +plant structures to that end.</p> + +<p>What I want to point out at present are the principles and not +so much the details of reproduction, and I wish you to notice, as I +proceed, what is true not only of reproduction in plants but also +of all processes in nature, namely, the paucity of typical methods +of attaining the given end, and the multiplicity of special +variation from those typical methods. When we see the wonderfully +varied forms of plant life, and yet learn that, so to speak, each +edifice is built with the same kind of brick, called a cell, +modified in form and function; when we see the smallest and +simplest equally with the largest and most complicated plant +increasing in size subject to the laws of growth by intussusception +and cell division, which are universal in the organic world; we +should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types.</p> + +<p>The first great generalization is into--</p> + +<p>1. The vegetative type of reproduction, in which one or more +ordinary cells separate from the parent plant and become an +independent plant; and--</p> + +<p>2. The special-cell type of reproduction, in which either one +special cell reproduces the plant, or two special cells by their +union form the origin of the new plant; these two modifications of +the process are known respectively as asexual and sexual.</p> + +<p>The third modification is a combination of the two others, +namely, the asexual special cell does not directly reproduce its +parent form, but gives rise to a structure in which sexual special +cells are developed, from whose coalescence springs again the +likeness of the original plant. This is termed alternation of +generations.</p> + +<p>The sexual special cell is termed the <i>spore</i>.</p> + +<p>The sexual special cells are of one kind or of two kinds.</p> + +<p>Those which are of one kind may be termed, from their habit of +yoking themselves together, <i>zygoblasts</i>, or conjugating +cells.</p> + +<p>Those which are of two kinds are, first, a generally aggressive +and motile fertilizing or so-called "male cell," called in its +typical form an <i>antherozoid</i>; and, second, a passive and +motionless receptive or so-called "female cell," called an +<i>oosphere</i>.</p> + +<p>The product of the union of two zygoblasts is termed a +<i>zygospore</i>.</p> + +<p>The product of the union of an antherozoid and an oosphere is +termed an <i>oospore</i>.</p> + +<p>In many cases the differentiation of the sexual cells does not +proceed so far as the formation of antherozoids or of distinct +oospheres; these cases I shall investigate with the others in +detail presently.</p> + +<p>First, then, I will point out some of the modes of vegetative +reproduction.</p> + +<p>The commonest of these is cell division, as seen in unicellular +plants, such as protococcus, where the one cell which composes the +plant simply divides into two, and each newly formed cell is then a +complete plant.</p> + +<p>The particular kind of cell division termed "budding" here +deserves mention. It is well seen in the yeast-plant, where the +cell bulges at one side, and this bulge becomes larger until it is +nipped off from the parent by contraction at the point of junction, +and is then an independent plant.</p> + +<p>Next, there is the process by which one plant becomes two by the +dying off of some connecting portion between two growing parts.</p> + +<p>Take, for instance, the case of the liverworts. In these there +is a thallus which starts from a central point and continually +divides in a forked or dichotomous manner. Now, if the central +portion dies away, it is obvious that there will be as many plants +as there were forkings, and the further the dying of the old end +proceeds, the more young plants will there be.</p> + +<p>Take again, among higher plants, the cases of suckers, runners, +stolons, offsets, etc. Here, by a process of growth but little +removed from the normal, portions of stems develop adventitious +roots, and by the dying away of the connecting links may become +independent plants.</p> + +<p>Still another vegetative method of reproduction is that by +bulbils or gemmæ.</p> + +<p>A bulbil is a bud which becomes an independent plant before it +commences to elongate; it is generally fleshy, somewhat after the +manner of a bulb, hence its name. Examples occur in the axillary +buds of <i>Lilium bulbiferum</i>, in some <i>Alliums</i>, etc.</p> + +<p>The gemma is found most frequently in the liverworts and mosses, +and is highly characteristic of these plants, in which indeed +vegetative reproduction maybe said to reach its fullest and most +varied extent.</p> + +<p>Gemmæ are here formed in a sort of flat cup, by division +of superficial cells of the thallus or of the stem, and they +consist when mature of flattened masses of cells, which lie loose +in the cup, so that wind or wet will carry them away on to soil or +rock, when, either by direct growth from apical cells, as with +those of the liverworts, or with previous emission of thread-like +cells forming a "protonema," in the case of the mosses, the young +plant is produced from them.</p> + +<p>The lichens have a very peculiar method of gemmation. The +lichen-thallus is composed of chains or groups of round +chlorophyl-containing cells, called "gonidia," and masses of +interwoven rows of elongated cells which constitute the +hyphæ. Under certain conditions single cells of the gonidia +become surrounded with a dense felt of hyphæ, these +accumulate in numbers below the surface of the thallus, until at +last they break out, are blown or washed away, and start +germination by ordinary cell division, and thus at once reproduce a +fresh lichen-thallus. These masses of cells are called soredia.</p> + +<p>Artificial budding and grafting do not enter into the scope of +this paper.</p> + +<p>As in the general growth and the vegetative reproduction of +plants cell-division is the chief method of cell formation, so in +the reproduction of plants by special cells the great feature is +the part played by cells which are produced not by the ordinary +method of cell division, but by one or the other processes of cell +formation, namely, free-cell formation or rejuvenescence.</p> + +<p>If we broaden somewhat the definition of rejuvenescence and +free-cell formation, and do not call the mother-cells of spores of +mosses, higher cryptogams, and also the mother-cells of +pollen-grains, reproductive cells, which strictly speaking they are +not, but only producers of the spores or pollen-grains, then we may +say that <i>cell-division is confined to vegetative processes, +rejuvenescence and free-cell formation are confined to reproductive +processes</i>.</p> + +<p>Rejuvenescence may be defined as the rearrangement of the whole +of the protoplasm of a cell into a new cell, which becomes free +from the mother-cell, and may or may not secrete a cell-wall around +it.</p> + +<p>If instead of the whole protoplasm of the cell arranging itself +into one mass, it divides into several, or if portions only of the +protoplasm become marked out into new cells, in each case +accompanied by rounding off and contraction, the new cells +remaining free from one another, and usually each secreting a cell +wall, then this process, whose relation to rejuvenescence is +apparent, is called free-cell formation.</p> + +<p>The only case of purely vegetative cell-formation which takes +place by either of these processes is that of the formation of +endosperm in Selaginella and phanerogams, which is a process of +free-cell formation.</p> + +<p>On the other hand, the universal contraction and rounding off of +the protoplasm, and the formation by either rejuvenescence or +free-cell formation, distinctly mark out the special or true +reproductive cell.</p> + +<p>Examples of reproductive cells formed by rejuvenescence are:</p> + +<p>1. The swarm spores of many algæ, as Stigeoclonium +(figured in Sachs' "Botany"). Here the contents of the cell +contract, rearrange themselves, and burst the side of the +containing wall, becoming free as a reproductive cell.</p> + +<p>2. The zygoblasts of conjugating algæ, as in Spirogyra. +Here the contents of a cell contract and rearrange themselves only +after contact of the cell with one of another filament of the +plant. This zygoblast only becomes free after the process of +conjugation, as described below.</p> + +<p>3. The oosphere of characeæ, mosses and liverworts, and +vascular cryptogams, where in special structures produced by +cell-divisions there arise single primordial cells, which divide +into two portions, of which the upper portion dissolves or becomes +mucilaginous, while the lower contracts and rearranges itself to +form the oosphere.</p> + +<p>4. Spores of mosses and liverworts, of vascular cryptogams, and +pollen cells of phanerogams, which are the analogue of the +spores.</p> + +<p>The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes +a wall of its own, and by the bursting or absorption of the wall of +its mother-cell becomes free. This is evidently a +rejuvenescence.</p> + +<p>Examples of reproductive cells formed by free-cell formation +are:</p> + +<p>1. The ascospores of fungi and algæ.</p> + +<p>2. The zoospores or mobile spores of many algæ and +fungi.</p> + +<p>3. The germinal vesicles of phanerogams.</p> + +<p>The next portion of my subject is the study of the methods by +which these special cells reproduce the plant.</p> + +<p>1st. Asexual methods.</p> + +<p>1. Rejuvenescence gives rise to a swarm-spore or zoospore. The +whole of the protoplasm of a cell contracts, becomes rounded and +rearranged, and escapes into the water, in which the plant floats +as a mass of protoplasm, clear at one end and provided with cilia +by which it is enabled to move, until after a time it comes to +rest, and after secreting a wall forms a new plant by ordinary +cell-division. Example: Oedogonium.</p> + +<p>2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya.</p> + +<p>3. Free-cell formation forms the typical motionless spore of +algæ and fungi. For instance, in the asci of lichens there +are formed from a portion of the protoplasm four or more small +ascospores, which secrete a cell-wall and lie loose in the ascus. +Occasionally these spores may consist of two or more cells. They +are set free by the rupture of the ascus, and germinate by putting +out through their walls one or more filaments which branch and form +the thallus of a new individual. Various other spores formed in the +same way are known as <i>tetraspores</i>, etc.</p> + +<p>4. Cell-division with rejuvenescence forms the spores of mosses +and higher cryptogams.</p> + +<p>To take the example of moss spores:</p> + +<p>Certain cells in the sporogonium of a moss are called +mother-cells. The protoplasm of each one of these becomes divided +into four parts. Each of these parts then secretes a cell-wall and +becomes free as a spore by the rupture or absorption of the wall of +the mother-cell. The germination of the spores I shall describe +later.</p> + +<p>5. A process of budding which in the yeast plant and in mosses +is merely vegetatively reproductive, in fungi becomes truly +reproductive, namely, the buds are special cells arising from other +special cells of the hyphæ.</p> + +<p>For example, the so-called "gills" of the common mushroom have +their surface composed of the ends of the threads of cells +constituting the hyphæ. Some of these terminal cells push out +a little finger of protoplasm, which swells, thickens its wall, and +becomes detached from the mother-cell as a spore, here called +specially a <i>basidiospore</i>.</p> + +<p>Also in the common gray mould of infusions and preserves, +Penicillium, by a process which is perhaps intermediate between +budding and cell-division, a cell at the end of a hypha constricts +itself in several places, and the constricted portions become +separate as <i>conidiospores</i>.</p> + +<p><i>Teleutospores, uredospores</i>, etc., are other names for +spores similarly formed.</p> + +<p>These conidiospores sometimes at once develop hyphæ, and +sometimes, as in the case of the potato fungus, they turn out their +contents as a swarm-spore, which actively moves about and +penetrates the potato leaves through the stomata before they come +to rest and elongate into the hyphal form.</p> + +<p>So far for asexual methods of reproduction.</p> + +<p>I shall now consider the sexual methods.</p> + +<p>The distinctive character of these methods is that the cell from +which the new individual is derived is incapable of producing by +division or otherwise that new individual without the aid of the +protoplasm of another cell.</p> + +<p>Why this should be we do not know; all that we can do is to +guess that there is some physical or chemical want which is only +supplied through the union of the two protoplasmic masses. The +process is of benefit to the species to which the individuals +belong, since it gives it a greater vigor and adaptability to +varying conditions, for the separate peculiarities of two +individuals due to climatic or other conditions are in the new +generation combined in one individual.</p> + +<p>The simplest of the sexual processes is conjugation. Here the +two combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union.</p> + +<p>Conjugation occurs in algæ and fungi. A typical case is +that of Spirogyra. This is an alga with its cells in long +filaments. Two contiguous cells of two parallel filaments push each +a little projection from its cell-wall toward the other. When these +meet, the protoplasm of each of the two cells contracts, and +assumes an elliptical form--it undergoes rejuvenescence. Next an +opening forms where the two cells are in contact, and the contents +of one cell pass over into the other, where the two protoplasmic +bodies coalesce, contract, and develop a cell-wall. The zygospore +thus formed germinates after a long period and forms a new filament +of cells.</p> + +<p>Another example of conjugation is that of Pandorina, an alga +allied to the well-known volvox. Here the conjugating cells swim +free in water; they have no cell-wall, and move actively by cilia. +Two out of a number approach, coalesce, contract, and secrete a +cell-wall. After a long period of rest, this zygospore allows the +whole of its contents to escape as a swarm-spore, which after a +time secretes a gelatinous wall, and by division reproduces the +sixteen-celled family.</p> + +<p>We now come to fertilization, where the uniting cells are of two +kinds.</p> + +<p>The simplest case is that of Vaucheria, an alga. Here the +vegetative filament puts out two protuberances, which become shut +off from the body of the filament by partitions. The protoplasm in +one of these protuberances arranges itself into a round mass--the +oosphere or female cell. The protoplasm of the other protuberance +divides into many small masses, furnished with cilia, the +spermatozoids or male cells. Each protuberance bursts, and some of +the spermatozoids come in contact with and are absorbed by the +oosphere, which then secretes a cell-wall, and after a time +germinates.</p> + +<p>The most advanced type of fertilization is that of +angiosperms.</p> + +<p>In them there are these differences from the above process: the +contents of the male cell, represented by the pollen, are not +differentiated into spermatozoids, and there is no actual contact +between the contents of the pollen tube and the germinal vesicle, +but according to Strashurger, there is a transference of the +substance of the nucleus of the pollen cell to that of the germinal +vesicle by osmose. The coalescence of the two nuclei within the +substance of the germinal vesicle causes the latter to secrete a +wall, and to form a new plant by division, being nourished the +while by the mother plant, from whose tissues the young embryo +plant contained in the seed only becomes free when it is in an +advanced stage of differentiation.</p> + +<p>Perhaps the most remarkable cases of fertilization occur in the +Florideæ or red seaweeds, to which class the well-known Irish +moss belongs.</p> + +<p>Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, +some other cell which is quite distinct from the primarily +fertilized cell carries on the reproductive process.</p> + +<p>If the allied group of the Coleochæteæ is considered +together with the Florideæ, we find a transition between the +ordinary case of Coleochæte and that of Dudresnaya. In +Coleochæte, the male cell is a round spermatozoid, and the +female cell an oosphere contained in the base of a cell which is +elongated into an open and hair-like tube called the trichogyne. +The spermatozoid coalesces with the oosphere, which secretes a +wall, becomes surrounded with a covering of cells called a +cystocarp, which springs from cells below the trichogyne, and after +the whole structure falls from the parent plant, spores are +developed from the oospore, and from them arises a new +generation.</p> + +<p>In Dudresnaya, on the other hand, the spermatozoid coalesces +indeed with the trichogyne, but this does not develop further. From +below the trichogyne, however, spring several branches, which run +to the ends of adjacent branches, with the apical cells of which +they conjugate, and the result of this conjugation is the +development of a cystocarp similar to that of Coleochæte. The +remarkable point here is the way in which the effect of the +fertilizing process is carried from one cell to another entirely +distinct from it.</p> + +<p>Thus I have endeavored to sum up the processes of asexual and of +sexual reproduction. But it is a peculiar characteristic of most +classes of plants that the cycle of their existence is not complete +until both methods of reproduction have been called into play, and +that the structure produced by one method is entirely different +from that produced by the other method.</p> + +<p>Indeed, it is only in some algæ and fungi that the +reproductive cells of one generation produce a generation similar +to the parent; in all other plants a generation A produces are +unlike generation B, which may either go on to produce another +generation, C, and then back to A, or it may go on producing B's +until one of these reproduces A, or again it may directly +reproduce; A. Thus we have the three types:</p> + +<pre> + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. +</pre> + +<p>The first case is not common, the usual number of generations +being two only; but a typical example of the occurrence of three +generations is in such fungi as <i>Puccinia Graminis</i>. Here the +first generation grows on barberry leaves, and produces a kind of +spore called an <i>æcidium spore</i>. These æcidium +spores germinate only on a grass stem or leaf, and a distinct +generation is produced, having a particular kind of spore called an +<i>uredospore</i>. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation +with another kind of spore, called a <i>teleutospore</i>, is +produced.</p> + +<p>The teleutospores only germinate on barberry leaves, and there +reproduce the original æcidium generation.</p> + +<p>Thus we have the series A.B.B.B ... BCA</p> + +<p>In this instance all the generations are asexual, but the most +common case is for the sexual and the asexual generations to +alternate. I will describe as examples the reproduction of a moss, +a fern, and a dicotyledon.</p> + +<p>In such a typical moss as Funaria, we have the following cycle +of developments: The sexual generation is a dioecious leafy +structure, having a central elongated axis, with leaves arranged +regularly around and along it. At the top of the axis in the male +plant rise the antheridia, surrounded by an envelope of modified +leaves called the perigonium. The antheridia are stalked sacs, with +a single wall of cells, and the spiral antherozoids arise by +free-cell formation from the cells of the interior. They are +discharged by the bursting of the antheridium, together with a +mucilage formed of the degraded walls of their mother cells.</p> + +<p>In the female plant there arise at the apex of the stem, +surrounded by an envelope of ordinary leaves, several archegonia. +These are of the ordinary type of those organs, namely, a broad +lower portion, containing a naked oosphere and a long narrow neck +with a central canal leading to the oosphere. Down this canal pass +one or more antherozoids, which become absorbed into the oosphere, +and this then secretes a wall, and from it grows the second or +asexual generation. The peculiarity of this asexual or +spore-bearing plant is that it is parasitic on the sexual plant; +the two generations, although not organically connected, yet remain +in close contact, and the spore-bearing generation is at all events +for a time nourished by the leafy sexual generation.</p> + +<p>The spore-bearing generation consists of a long stalk, closely +held below by the cells of the base of the archegonium; this +supports a broadened portion which contains the spores, and the top +is covered with the remains of the neck of the archegonium forming +the calyptra.</p> + +<p>The spores arise from special or mother-cells by a process of +division, or it may be even termed free-cell formation, the +protoplasm of each mother-cell dividing into four parts, each of +which contracts, secretes a wall, and thus by rejuvenescence +becomes a spore, and by the absorption of the mother-cells the +spores lie loose in the spore sac. The spores are set free by the +bursting of their chamber, and each germinates, putting out a +branched thread of cells called a protonema, which may perhaps +properly be termed a third generation in the cycle of the plant; +for it is only from buds developed on this protonema that the leafy +sexual plant arises.</p> + +<p>The characteristics, then, of the mosses are, that the sexual +generation is leafy, the one or two asexual generations are +thalloid, and that the spore-bearing generation is in parasitic +connection with the sexual generation.</p> + +<p>In the case of the fern, these conditions are very +different.</p> + +<p>The sexual generation is a small green thalloid structure called +a prothallium, which bears antheridia and archegonia, each +archegonium having a neck-canal and oosphere, which is fertilized +just as in the moss.</p> + +<p>But the asexual generation derived from the oospore only for a +short while remains in connection with the prothallium, which, of +course, answers to the leafy portion of the moss. What is generally +known as the fern is this asexual generation, a great contrast to +the small leafless moss fruit or sporogonium as it is called, to +which it is morphologically equivalent. On the leaves of this +generation arise the sporangia which contain the spores. The spores +are formed in a manner very similar to those of the mosses, and are +set free by rupture of the sporangium.</p> + +<p>The spore produces the small green prothallium by cell-division +in the usual way, and this completes the cycle of fern life.</p> + +<p>The alternation of generations, which is perhaps most clear and +typical in the case of the fern, becomes less distinctly marked in +the plants of higher organization and type.</p> + +<p>Thus in the Rhizocarpæ there are two kinds of spores, +<i>microspores</i> and <i>macrospores</i>, producing prothallia +which bear respectively antheridia and archegonia; in the +Lycopodiaceæ, the two kinds of spores produce very +rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the +endosperm, in which archegonia or corpuscula are formed; and +lastly, in typical dicotyledons it is only lately that any trace of +a prothallium from the microspore or pollen cell has been +discovered, while the macrospore or embryo-sac produces only two or +three prothallium cells, known as antipodal cells, and two or three +oospheres, known as germinal vesicles.</p> + +<p>This description of the analogies of the pollen and embryo-sac +of dicotyledons assumes that the general vegetative structure of +this class of plants is equivalent to the asexual generation of the +higher cryptogams. In describing their cycle of reproduction I will +endeavor to show grounds for this assumption.</p> + +<p>We start with the embryo as contained in the seed. This embryo +is the product of fertilization of a germinal vesicle by a pollen +tube. Hence, by analogy with the product of fertilization of +rhizocarp's, ferns, and mosses, it should develop into a spore +bearing plant. It does develop into a plant in which on certain +modified leaves are produced masses of tissue in which two kinds of +special reproductive cells are formed. This is precisely analogous +to the case of gymnosperms, lycopods, etc., where on leaf +structures are formed macro and micro sporangia.</p> + +<p>To deal first with the microsporangium or pollen-sac. The pollen +cells are formed from mother cells by a process of cell division +and subsequent setting free of the daughter cells or pollen cells +by rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceæ, etc. The +subsequent behavior of the pollen cell, its division and its +fertilization of the germinal vesicle or oosphere, leave no doubt +as to its analogy with the microspore of vascular cryptogams.</p> + +<p>Secondly, the nucleus of the ovule corresponds with the +macrosporangium of Selaginella, through the connecting link of the +conifers, where the ovule is of similar origin and position to the +macrosporangium of the Lycopodiaceæ. But the formation of the +macrospore or embryo-sac is simpler than the corresponding process +in cryptogams. It arises by a simple enlargement of one cell of the +nucleus instead of by the division of one cell into four, each thus +becoming a macrospore. At the top of this macrospore or embryo-sac +two or three germinal vesicles are formed by free cell formation, +and also two or three cells called antipodal cells, since they +travel to the other end of the embryo-sac; these latter represent a +rudimentary prothallium. This formation of germinal vesicles and +prothallium seems very different from the formation of archegonia +and prothallium in Selaginella, for instance; but the link which +connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed.</p> + +<p>Thus we see that the flowering plant is essentially the +equivalent of the asexual fern, and of the sporogonium of the moss, +and the pollen cell and the embryo-sac represent the two spores of +the higher cryptogams, and the pollen tube and the germinal +vesicles and antipodal cells are all that remain of the sexual +generation, seen in the moss as a leafy plant, and in the fern as a +prothallium. Indeed, when a plant has monoecious or dioecious +flowers, the distinction between the asexual and the sexual +generation has practically been lost, and the spore-bearing +generation has become identified with the sexual generation.</p> + +<p>Having now described the formation of the pollen and the +germinal vesicles, it only remains to show how they form the +embryo. The pollen cell forms two or three divisions, which are +either permanent or soon absorbed; this, as before stated, is the +rudimentary male prothallium. Then when it lies on the stigma it +develops a long tube, which passes down the style and through the +micropyle of the ovule to the germinal vesicles, one of which is +fertilized by what is probably an osmotic transference of nuclear +matter. The germinal vesicle now secretes a wall, divides into two +parts, and while the rest of the embyro-sac fills with endosperm +cells, it produces by cell division from the upper half a short row +of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or +leafy plant, and while in the fern each generation is an +independent structure, here in the dicotyledon, on the other hand, +the asexual generation or embryo is again for a time nourished in +the interior of the embryo-sac representing the sexual generation, +and this again derives its nourishment from the previous asexual +generation, so that as in the moss, there is again a partial +parasitism of one generation on the other.</p> + +<p>To sum up the methods of plant reproduction: They resolve +themselves into two classes.</p> + +<p>1st. Purely vegetative.</p> + +<p>2d. Truly reproductive by special cells.</p> + +<p>In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive +methods.</p> + +<p>1st. Reproduction from an asexual spore.</p> + +<p>2d. Reproduction from an oospore formed by the combination of +two sexual cells.</p> + +<p>In the vast majority of plant species these two types are used +by the individuals alternately.</p> + +<p>The extraordinary similarity of the reproductive process, as +shown in the examples I have given, Achlya, Spirogyra, and +Vaucheria among algæ, the moss, the fern, and the flowering +plant, a similarity which becomes the more marked the more the +details of each case and of the cases of plants which form links +between these great classes are studied, points to a community of +origin of all plants in some few or one primeval ancestor. And to +this inference the study of plant structure and morphology, +together with the evidence of palæobotany among other +circumstances, lends confirmatory evidence, and all modern +discoveries, as for instance that of the rudimentary prothallium +formed by the pollen of angiosperms, tend to the smoothing of the +path by which the descent of the higher plants from simpler types +will, as I think, be eventually shown.</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. 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531, March 6, 1886, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Scientific American Supplement, Vol. XXI., No. 531, March 6, 1886 + +Author: Various + +Release Date: February 29, 2004 [EBook #11383] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPP. 531 *** + + + + +Produced by Produced by Josephine Paolucci, Don Kretz, Juliet Sutherland, +Charles Franks and the DP Team + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 531 + + + + +NEW YORK, MARCH 6, 1886 + +Scientific American Supplement. Vol. XXI, No. 531. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + +TABLE OF CONTENTS. + +I. CHEMISTRY AND METALLURGY.--Annatto.-Analyses of the same.--By + WM. LAWSON + + Aluminum.--By J.A. PRICE.--Iron the basis of civilization.-- + Aluminum the metal of the future.--Discovery of aluminum.--Art + of obtaining the metal.--Uses and possibilities + +II. ENGINEERING AND MECHANICS.--The Use of Iron in Fortification. + --Armor-plated casements.--The Schumann-Gruson chilled iron + cupola.--Mougin's rolled iron cupola.--With full page + of engravings + + High Speed on the Ocean + + Sibley College Lectures.--Principles and Methods of Balancing + Forces developed in Moving Bodies.--Momentum and centrifugal + force.--By CHAS.T. PORTER.--3 figures + + Compressed Air Power Schemes.--By J. STURGEON.--Several + figures + + The Berthon Collapsible Canoe.--2 engravings + + The Fiftieth Anniversary of the Opening of the First German + Steam Railroad.--With full page engraving + + Improved Coal Elevator.--With engraving + +III. TECHNOLOGY.--Steel-making Ladles.--4 figures + + Water Gas.--The relative value of water gas and other gases as + Iron-reducing Agents.--By B.H. THWAITE.--Experiments.--With + tables and 1 figure + + Japanese Rice Wine and Soja Sauce.--Method of making + +IV. ELECTRICITY, MICROSCOPY, ETC.-Apparatus for demonstrating + that Electricity develops only on the Surface of Conductors.--1 + figure + + The Colson Telephone.--3 engravings + + The Meldometer.--An apparatus for determining the melting + points of minerals + + Touch Transmission by Electricity in the Education of Deaf + Mutes.--By S. TEFFT WALKER.--With 1 figure + +V. HORTICULTURE.--Candelabra Cactus and the California Woodpecker.--By + C.F. HOLDER.--With 2 engravings + + How Plants are reproduced.--By C.E. STUART.--A paper read + before the Chemists' Assistants' Association + +VI. MISCELLANEOUS--The Origin of Meteorites.--With 1 figure + + * * * * * + + + + +THE USE OF IRON IN FORTIFICATION. + + +Roumania is thinking of protecting a portion of the artillery of the +forts surrounding her capital by metallic cupolas. But, before deciding +upon the mode of constructing these formidable and costly affairs, and +before ordering them, she has desired to ascertain their efficacy and +the respective merits of the chilled iron armor which was recently in +fashion and of rolled iron, which looks as if it were to be the fashion +hereafter. + +[Illustration: FIG. 1.--MOUGIN'S ROLLED IRON TURRET.] + +The Krupp works have recommended and constructed a cupola of +casehardened iron, while the Saint Chamond works have offered a turret +of rolled iron. Both of these recommend themselves by various merits, +and by remarkably ingenious arrangements, and it only remains to be seen +how they will behave under the fire of the largest pieces of artillery. + +[Illustration: FIG. 2.] + +We are far in advance of the time when cannons with smooth bore were +obliged to approach to within a very short range of a scarp in order to +open a breach, and we are far beyond that first rifled artillery which +effected so great a revolution in tactics. + +[Illustration: FIG. 3.] + +To-day we station the batteries that are to tear open a rampart at +distances therefrom of from 1,000 to 2,000 yards, and the long, 6 inch +cannon that arms them has for probable deviations, under a charge of 20 +pounds of powder, and at a distance of 1,000 yards, 28 feet in range, 16 +inches in direct fire and 8 inches in curved. + +The weight of the projectile is 88 pounds, and its remanent velocity at +the moment of impact is 1,295 feet. Under this enormous live force, the +masonry gradually crumbles, and carries along the earth of the parapet, +and opens a breach for the assaulting columns. + +[Illustration: FIG. 4--STATE OF A CUPOLA AFTER THE ACTION OF +THIRTY-SEVEN 6 IN. PROJECTILES.] + +In order to protect the masonry of the scarp, engineers first lowered +the cordon to the level of the covert-way. Under these circumstances, +the enemy, although he could no longer see it, reached it by a curved or +"plunging" shot. When, in fact, for a given distance we load a gun with +the heaviest charge that it will stand, the trajectory, AMB (Fig. 2), is +as depressed as possible, and the angles, a and a', at the start and +arrival are small, and we have a direct shot. If we raise the chase of +the piece, the projectile will describe a curve in space which would be +a perfect parabola were it not for the resistance of the air, and the +summit of such curve will rise in proportion as the angle so increases. +So long as the falling angle, a, remains less than 45 deg., we shall have a +curved shot. When the angle exceeds this, the shot is called "vertical." +If we preserve the same charge, the parabolic curve in rising will meet +the horizontal plane at a greater distance off. This is, as well known, +the process employed for reaching more and more distant objects. + +[Illustration: Fig. 5.--STATE OF A CAST-IRON CUPOLA AFTER THE BREAKAGE +OF A VOUSSOIR.] + +The length of a gun depends upon the maximum charge burned in it, since +the combustion must be complete when the projectile reaches the open +air. It results from this that although guns of great length are capable +of throwing projectiles with small charges, it is possible to use +shorter pieces for this purpose--such as howitzers for curved shots and +mortars for vertical ones. The curved shot finds one application in the +opening of breaches in scarp walls, despite the existence of a covering +of great thickness. If, from a point, a (Fig. 3), we wish to strike the +point, b, of a scarp, over the crest, c, of the covert-way, it will +suffice to pass a parabolic curve through these three points--the +unknown data of the problem, and the charge necessary, being +ascertained, for any given piece, from the artillery tables. In such +cases it is necessary to ascertain the velocity at the impact, since the +force of penetration depends upon the live force (mv squared) of the +projectile, and the latter will not penetrate masonry unless it have +sufficient remanent velocity. Live force, however, is not the sole +factor that intervenes, for it is indispensable to consider the angle at +which the projectile strikes the wall. Modern guns, such as the Krupp 6 +inch and De Bange 6 and 8 inch, make a breach, the two former at a +falling angle of 22 deg., and the latter at one of 30 deg.. It is not easy to +lower the scarps enough to protect them from these blows, even by +narrowing the ditch in order to bring them near the covering mass of the +glacis. + +The same guns are employed for dismounting the defender's pieces, which +he covers as much as possible behind the parapet. Heavy howitzers +destroy the _materiel_, while shrapnel, falling nearly vertically, and +bursting among the men, render all operations impossible upon an open +terre-plein. + +[Illustration: FIG. 6.--STATE OF A CHILLED IRON CUPOLA BROKEN BY A 12 +INCH BALL.] + +The effect of 6 and 8 inch rifled mortars is remarkable. The Germans +have a 9 inch one that weighs 3,850 pounds, and the projectile of which +weighs 300. But French mortars in nowise cede to those of their +neighbors; Col. De Bange, for example, has constructed a 101/2 inch one of +wonderful power and accuracy. + +Seeing the destructive power of these modern engines of war, it may well +be asked how many pieces the defense will be able to preserve intact for +the last period of a siege--for the very moment at which it has most +need of a few guns to hold the assailants in check and destroy the +assaulting columns. Engineers have proposed two methods of protecting +these few indispensable pieces. The first of these consists in placing +each gun under a masonry vault, which is covered with earth on all sides +except the one that contains the embrasure, this side being covered with +armor plate. + +The second consists in placing one or two guns under a metallic cupola, +the embrasures in which are as small as possible. The cannon, in a +vertical aim, revolves around the center of an aperture which may be of +very small dimensions. As regards direct aim, the carriages are +absolutely fixed to the cupola, which itself revolves around a vertical +axis. These cupolas may be struck in three different ways: (1) at right +angles, by a direct shot, and consequently with a full charge--very +dangerous blows, that necessitate a great thickness of the armor plate; +(2) obliquely, when the projectile, if the normal component of its real +velocity is not sufficient to make it penetrate, will be deflected +without doing the plate much harm; and (3) by a vertical shot that may +strike the armor plate with great accuracy. + +General Brialmont says that the metal of the cupola should be able to +withstand both penetration and breakage; but these two conditions +unfortunately require opposite qualities. A metal of sufficient +ductility to withstand breakage is easily penetrated, and, conversely, +one that is hard and does not permit of penetration does not resist +shocks well. Up to the present, casehardened iron (Gruson) has appeared +to best satisfy the contradictory conditions of the problem. Upon the +tempered exterior of this, projectiles of chilled iron and cast steel +break upon striking, absorbing a part of their live force for their own +breakage. + +In 1875 Commandant Mougin performed some experiments with a chilled iron +turret established after these plans. The thickness of the metal +normally to the blows was 231/2 inches, and the projectiles were of cast +steel. The trial consisted in firing two solid 12 in. navy projectiles, +46 cylindrical 6 in. ones, weighing 100 lb., and 129 solid, pointed +ones, 12 in. in diameter. The 6 inch projectiles were fired from a +distance of 3,280 feet, with a remanent velocity of 1,300 feet. The +different phases of the experiment are shown in Figs. 4, 5, and 6. The +cupola was broken; but it is to be remarked that a movable and +well-covered one would not have been placed under so disadvantageous +circumstances as the one under consideration, upon which it was easy to +superpose the blows. An endeavor was next made to substitute a tougher +metal for casehardened iron, and steel was naturally thought of. But +hammered steel broke likewise, and a mixed or compound metal was still +less successful. It became necessary, therefore, to reject hard metals, +and to have recourse to malleable ones; and the one selected was rolled +iron. Armor plate composed of this latter has been submitted to several +tests, which appear to show that a thickness of 18 inches will serve as +a sufficient barrier to the shots of any gun that an enemy can +conveniently bring into the field. + +[Illustration: FIG. 7.--CASEMATE OF CHILLED IRON AFTER RECEIVING +NINETY-SIX SHOTS.] + +_Armor Plated Casemates_.--Fig. 7 shows the state of a chilled iron +casemate after a vigorous firing. The system that we are about to +describe is much better, and is due to Commandant Mougin. + +[Illustration: FIG. 8.--MOUGIN'S ARMOR-PLATE CASEMATE.] + +The gun is placed under a vault whose generatrices are at right angles +to the line of fire (Fig. 8), and which contains a niche that traverses +the parapet. This niche is of concrete, and its walls in the vicinity of +the embrasure are protected by thick iron plate. The rectangular armor +plate of rolled iron rests against an elastic cushion of sand compactly +rammed into an iron plate caisson. The conical embrasure traverses this +cushion by means of a cast-steel piece firmly bolted to the caisson, and +applied to the armor through the intermedium of a leaden ring. +Externally, the cheeks of the embrasure and the merlons consist of +blocks of concrete held in caissons of strong iron plate. The +surrounding earthwork is of sand. For closing the embrasure, Commandant +Mougin provides the armor with a disk, c, of heavy rolled iron, which +contains two symmetrical apertures. This disk is movable around a +horizontal axis, and its lower part and its trunnions are protected by +the sloping mass of concrete that covers the head of the casemate. A +windlass and chain give the disk the motion that brings one of its +apertures opposite the embrasure or that closes the latter. When this +portion of the disk has suffered too much from the enemy's fire, a +simple maneuver gives it a half revolution, and the second aperture is +then made use of. + +_The Schumann-Gruson Chilled Iron Cupola_.--This cupola (Fig. 9) is +dome-shaped, and thus offers but little surface to direct fire; but it +can be struck by a vertical shot, and it may be inquired whether its top +can withstand the shock of projectiles from a 10 inch rifled mortar. It +is designed for two 6 inch guns placed parallel. Its internal diameter +is 191/2 feet, and the dome is 8 inches in thickness and has a radius of +161/2 feet. It rests upon a pivot, p, around which it revolves through the +intermedium of rollers placed in a circle, r. The dome is of relatively +small bulk--a bad feature as regards resistance to shock. To obviate +this difficulty, the inventor partitions it internally in such a way as +to leave only sufficient space to maneuver the guns. The partitions +consist of iron plate boxes filled with concrete. The form of the dome +has one inconvenience, viz., the embrasure in it is necessarily very +oblique, and offers quite an elongated ellipse to blows, and the edges +of the bevel upon a portion of the circumference are not strong enough. +In order to close the embrasure as tightly as possible, the gun is +surrounded with a ring provided with trunnions that enter the sides of +the embrasure. The motion of the piece necessary to aim it vertically is +effected around this axis of rotation. The weight of the gun is balanced +by a system of counterpoises and the chains, l, and the breech +terminates in a hollow screw, f, and a nut, g, held between two +directing sectors, h. The cupola is revolved by simply acting upon the +rollers. + +[Illustration: FIG. 9.--THE SCHUMANN-GRUSON CUPOLA.] + +_Mougin's Rolled Iron Cupola_.--The general form of this cupola (Fig. 1) +is that of a cylindrical turret. It is 123/4 feet in diameter, and rises +31/4 feet above the top of the glacis. It has an advantage over the one +just described in possessing more internal space, without having so +large a diameter; and, as the embrasures are at right angles with the +sides, the plates are less weakened. The turret consists of three plates +assembled by slit and tongue joints, and rests upon a ring of strong +iron plate strengthened by angle irons. Vertical partitions under the +cheeks of the gun carriages serve as cross braces, and are connected +with each other upon the table of the hydraulic pivot around which the +entire affair revolves. This pivot terminates in a plunger that enters a +strong steel press-cylinder embedded in the masonry of the lower +concrete vault. + +The iron plate ring carries wheels and rollers, through the intermedium +of which the turret is revolved. The circular iron track over which +these move is independent of the outer armor. + +The whole is maneuvered through the action of one man upon the piston of +a very small hydraulic press. The guns are mounted upon hydraulic +carriages. The brake that limits the recoil consists of two bronze pump +chambers, a and b (Fig. 10). The former of these is 4 inches in +diameter, and its piston is connected with the gun, while the other is 8 +inches in diameter, and its piston is connected with two rows of 26 +couples of Belleville springs, d. The two cylinders communicate through +a check valve. + +When the gun is in battery, the liquid fills the chamber of the 4 inch +pump, while the piston of the 8 inch one is at the end of its stroke. A +recoil has the effect of driving in the 4 inch piston and forcing the +liquid into the other chamber, whose piston compresses the springs. At +the end of the recoil, the gunner has only to act upon the valve by +means of a hand-wheel in order to bring the gun into battery as slowly +as he desires, through the action of the springs. + +[Illustration: FIG. 10.--MOUGIN'S HYDRAULIC GUN CARRIAGE.] + +For high aiming, the gun and the movable part of its carriage are +capable of revolving around a strong pin, c, so placed that the axis of +the piece always passes very near the center of the embrasure, thus +permitting of giving the latter minimum dimensions. The chamber of the 8 +inch pump is provided with projections that slide between circular +guides, and carries the strap of a small hydraulic piston, p, that +suffices to move the entire affair in a vertical plane, the gun and +movable carriage being balanced by a counterpoise, q. + +The projectiles are hoisted to the breech of the gun by a crane. + +Between the outer armor and turret sufficient space is left for a man to +enter, in order to make repairs when necessary. + +Each of the rolled iron plates of which the turret consists weighs 19 +tons. The cupolas that we have examined in this article have been +constructed on the hypothesis than an enemy will not be able to bring +into the field guns of much greater caliber than 6 inches.--_Le Genie +Civil_. + + * * * * * + + + + +HIGH SPEED ON THE OCEAN. + + +_To the Editor of the Scientific American_: + +Although not a naval engineer, I wish to reply to some arguments +advanced by Capt. Giles, and published in the SCIENTIFIC AMERICAN of +Jan. 2, 1886, in regard to high speed on the ocean. + +Capt. Giles argues that because quadrupeds and birds do not in +propelling themselves exert their force in a direct line with the plane +of their motion, but at an angle to it, the same principle would, if +applied to a steamship, increase its speed. But let us look at the +subject from another standpoint. The quadruped has to support the weight +of his body, and propel himself forward, with the same force. If the +force be applied perpendicularly, the body is elevated, but not moved +forward. If the force is applied horizontally, the body moves forward, +but soon falls to the ground, because it is not supported. But when the +force is applied at the proper angle, the body is moved forward and at +the same time supported. Directly contrary to Capt. Giles' theory, the +greater the speed of the quadruped, the nearer in a direct line with his +motion does he apply the propulsive force, and _vice versa_. This may +easily be seen by any one watching the motions of the horse, hound, +deer, rabbit, etc., when in rapid motion. The water birds and animals, +whose weight is supported by the water, do not exert the propulsive +force in a downward direction, but in a direct line with the plane of +their motion. The man who swims does not increase his motion by kicking +out at an angle, but by drawing the feet together with the legs +straight, thus using the water between them as a double inclined plane, +on which his feet and legs slide and thus increase his motion. The +weight of the steamship is already supported by the water, and all that +is required of the propeller is to push her forward. If set so as to act +in a direct line with the plane of motion, it will use all its force to +push her forward; if set so as to use its force in a perpendicular +direction, it will use all its force to raise her out of the water. If +placed at an angle of 45 deg. with the plane of motion, half the force will +be used in raising the ship out of the water, and only half will be left +to push her forward. + +ENOS M. RICKER. + +Park Rapids, Minn., Jan. 23, 1886. + + * * * * * + + + + +SIBLEY COLLEGE LECTURES. + +BY THE CORNELL UNIVERSITY NON-RESIDENT LECTURERS IN MECHANICAL +ENGINEERING. + + + + +PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING BODIES. + +BY CHAS. T. PORTER. + +INTRODUCTION. + + +On appearing for the first time before this Association, which, as I am +informed, comprises the faculty and the entire body of students of the +Sibley College of Mechanical Engineering and the Mechanic Arts, a +reminiscence of the founder of this College suggests itself to me, in +the relation of which I beg first to be indulged. + +In the years 1847-8-9 I lived in Rochester, N.Y., and formed a slight +acquaintance with Mr. Sibley, whose home was then, as it has ever since +been, in that city. Nearly twelve years afterward, in the summer of +1861, which will be remembered as the first year of our civil war, I met +Mr. Sibley again. We happened to occupy a seat together in a car from +New York to Albany. He recollected me, and we had a conversation which +made a lasting impression on my memory. I said we had a conversation. +That reminds me of a story told by my dear friend, of precious memory, +Alexander L. Holley. One summer Mr. Holley accompanied a party of +artists on an excursion to Mt. Katahdin, which, as you know, rises in +almost solitary grandeur amid the forests and lakes of Maine. He wrote, +in his inimitably happy style, an account of this excursion, which +appeared some time after in _Scribner's Monthly_, elegantly illustrated +with views of the scenery. Among other things, Mr. Holley related how he +and Mr. Church painted the sketches for a grand picture of Mt. Katahdin. +"That is," he explained, "Mr. Church painted, and I held the umbrella." + +This describes the conversation which Mr. Sibley and I had. Mr. Sibley +talked, and I listened. He was a good talker, and I flatter myself that +I rather excel as a listener. On that occasion I did my best, for I knew +whom I was listening to. I was listening to the man who combined bold +and comprehensive grasp of thought, unerring foresight and sagacity, and +energy of action and power of accomplishment, in a degree not surpassed, +if it was equaled, among men. + +Some years before, Mr. Sibley had created the Western Union Telegraph +Company. At that time telegraphy was in a very depressed state. The +country was to a considerable extent occupied by local lines, chartered +under various State laws, and operated without concert. Four rival +companies, organized under the Morse, the Bain, the House, and the +Hughes patents, competed for the business. Telegraph stock was nearly +valueless. Hiram Sibley, a man of the people, a resident of an inland +city, of only moderate fortune, alone grasped the situation. He saw that +the nature of the business, and the demands of the country, alike +required that a single organization, in which all interests should be +combined, should cover the entire land with its network, by means of +which every center and every outlying point, distant as well as near, +could communicate with each other directly, and that such an +organization must be financially successful. He saw all this vividly, +and realized it with the most intense earnestness of conviction. With +Mr. Sibley, to be convinced was to act; and so he set about the task of +carrying this vast scheme into execution. The result is well known. By +his immense energy, the magnetic power with which he infused his own +convictions into other minds, the direct, practical way in which he set +about the work, and his indomitable perseverance, Mr. Sibley attained at +last a phenomenal success. + +But he was not then telling me anything about this. He was telling me of +the construction of the telegraph line to the Pacific Coast. Here again +Mr. Sibley had seen that which was hidden from others. This case +differed from the former one in two important respects. Then Mr. Sibley +had been dependent on the aid and co-operation of many persons; and this +he had been able to secure. Now, he could not obtain help from a human +being; but he had become able to act independently of any assistance. + +He had made a careful study of the subject, in his thoroughly practical +way, and had become convinced that such a line was feasible, and would +be remunerative. At his instance a convention of telegraph men met in +the city of New York, to consider the project. The feeling in this +convention was extremely unfavorable to it. A committee reported against +it unanimously, on three grounds--the country was destitute of timber, +the line would be destroyed by the Indians, and if constructed and +maintained, it would not pay expenses. Mr. Sibley found himself alone. +An earnest appeal which he made from the report of the committee was +received with derisive laughter. The idea of running a telegraph line +through what was then a wilderness, roamed over for between one and two +thousand miles of its breadth by bands of savages, who of course would +destroy the line as soon as it was put up, and where repairs would be +difficult and useless, even if the other objections to it were out of +the way, struck the members of the convention as so exquisitely +ludicrous that it seemed as if they would never be done laughing about +it. If Mr. Sibley had advocated a line to the moon, they would hardly +have seen in it greater evidence of lunacy. When he could be heard, he +rose again and said: "Gentlemen, you may laugh, but if I was not so old, +I would build the line myself." Upon this, of course, they laughed +louder than ever. As they laughed, he grew mad, and shouted: "Gentlemen, +I will bar the years, and do it." And he did it. Without help from any +one, for every man who claimed a right to express an opinion upon it +scouted the project as chimerical, and no capitalist would put a dollar +in it, Hiram Sibley built the line of telegraph to San Francisco, +risking in it all he had in the world. He set about the work with his +customary energy, all obstacles vanished, and the line was completed in +an incredibly short time. And from the day it was opened, it has proved +probably the most profitable line of telegraph that has ever been +constructed. There was the practicability, and there was the demand and +the business to be done, and yet no living man could see it, or could be +made to see it, except Hiram Sibley. "And to-day," he said, with honest +pride, "to-day in New York, men to whom I went almost on my knees for +help in building this line, and who would not give me a dollar, have +solicited me to be allowed to buy stock in it at the rate of five +dollars for one." + +"But how about the Indians?" I asked. "Why," he replied, "we never had +any trouble from the Indians. I knew we wouldn't have. Men who supposed +I was such a fool as to go about this undertaking before that was all +settled didn't know me. No Indian ever harmed that line. The Indians are +the best friends we have got. You see, we taught the Indians the Great +Spirit was in that line; and what was more, we proved it to them. It +was, by all odds, the greatest medicine they ever saw. They fairly +worshiped it. No Indian ever dared to do it harm." + +"But," he added, "there was one thing I didn't count on. The border +ruffians in Missouri are as bad as anybody ever feared the Indians might +be. They have given us so much trouble that we are now building a line +around that State, through Iowa and Nebraska. We are obliged to do it." + +This opened another phase of the subject. The telegraph line to the +Pacific had a value beyond that which could be expressed in money. It +was perhaps the strongest of all the ties which bound California so +securely to the Union, in the dark days of its struggle for existence. +The secession element in Missouri recognized the importance of the line +in this respect, and were persistent in their efforts to destroy it. We +have seen by what means their purpose was thwarted. + +I have always felt that, among the countless evidences of the ordering +of Providence by which the war for the preservation of the Union was +signalized, not the least striking was the raising up of this remarkable +man, to accomplish alone, and in the very nick of time, a work which at +once became of such national importance. + +This is the man who has crowned his useful career, and shown again his +eminently practical character and wise foresight, by the endowment of +this College, which cannot fail to be a perennial source of benefit to +the country whose interests he has done so much to promote, and which +his remarkable sagacity and energy contributed so much to preserve. + +We have an excellent rule, followed by all successful designers of +machinery, which is, to make provision for the extreme case, for the +most severe test to which, under normal conditions, and so far as +practicable under abnormal conditions also, the machinery can be +subjected. Then, of course, any demands upon it which are less than the +extreme demand are not likely to give trouble. I shall apply this +principle in addressing you to-day. In what I have to say, I shall speak +directly to the youngest and least advanced minds among my auditors. If +I am successful in making an exposition of my subject which shall be +plain to them, then it is evident that I need not concern myself about +being understood by the higher class men and the professors. + +The subject to which your attention is now invited is + + +THE PRINCIPLES AND METHODS OF BALANCING FORCES DEVELOPED IN MOVING +BODIES. + +This is a subject with which every one who expects to be concerned with +machinery, either as designer or constructor, ought to be familiar. The +principles which underlie it are very simple, but in order to be of use, +these need to be thoroughly understood. If they have once been mastered, +made familiar, incorporated into your intellectual being, so as to be +readily and naturally applied to every case as it arises, then you +occupy a high vantage ground. In this particular, at least, you will not +go about your work uncertainly, trying first this method and then that +one, or leaving errors to be disclosed when too late to remedy them. On +the contrary, you will make, first your calculations and then your +plans, with the certainty that the result will be precisely what you +intend. + +Moreover, when you read discussions on any branch of this subject, you +will not receive these into unprepared minds, just as apt to admit error +as truth, and possessing no test by which to distinguish the one from +the other; but you will be able to form intelligent judgments with +respect to them. You will discover at once whether or not the writers +are anchored to the sure holding ground of sound principles. + +It is to be observed that I do not speak of balancing bodies, but of +balancing forces. Forces are the realities with which, as mechanical +engineers, you will have directly to deal, all through your lives. The +present discussion is limited also to those forces which are developed +in moving bodies, or by the motion of bodies. This limitation excludes +the force of gravity, which acts on all bodies alike, whether at rest or +in motion. It is, indeed, often desirable to neutralize the effect of +gravity on machinery. The methods of doing this are, however, obvious, +and I shall not further refer to them. + +Two very different forces, or manifestations of force, are developed by +the motion of bodies. These are + + +MOMENTUM AND CENTRIFUGAL FORCE. + +The first of these forces is exerted by every moving body, whatever the +nature of the path in which it is moving, and always in the direction of +its motion. The latter force is exerted only by bodies whose path is a +circle, or a curve of some form, about a central body or point, to which +it is held, and this force is always at right angles with the direction +of motion of the body. + +Respecting momentum, I wish only to call your attention to a single +fact, which will become of importance in the course of our discussion. +Experiments on falling bodies, as well as all experience, show that the +velocity of every moving body is the product of two factors, which must +combine to produce it. Those factors are force and distance. In order to +impart motion to the body, force must act through distance. These two +factors may be combined in any proportions whatever. The velocity +imparted to the body will vary as the square root of their product. +Thus, in the case of any given body, + + Let force 1, acting through distance 1, impart velocity 1. + Then " 1, " " " 4, will " " 2, or + " 2, " " " 2, " " " 2, or + " 4, " " " 1, " " " 2; + And " 1, " " " 9, " " " 3, or + " 3, " " " 3, " " " 3, or + " 9, " " " 1, " " " 3. + +This table might be continued indefinitely. The product of the force +into the distance will always vary as the square of the final velocity +imparted. To arrest a given velocity, the same force, acting through the +same distance, or the same product of force into distance, is required +that was required to impart the velocity. + +The fundamental truth which I now wish to impress upon your minds is +that in order to impart velocity to a body, to develop the energy which +is possessed by a body in motion, force must act through distance. +Distance is a factor as essential as force. Infinite force could not +impart to a body the least velocity, could not develop the least energy, +without acting through distance. + +This exposition of the nature of momentum is sufficient for my present +purpose. I shall have occasion to apply it later on, and to describe the +methods of balancing this force, in those cases in which it becomes +necessary or desirable to do so. At present I will proceed to consider +the second of the forces, or manifestations of force, which are +developed in moving bodies--_centrifugal force_. + +This force presents its claims to attention in all bodies which revolve +about fixed centers, and sometimes these claims are presented with a +good deal of urgency. At the same time, there is probably no subject, +about which the ideas of men generally are more vague and confused. This +confusion is directly due to the vague manner in which the subject of +centrifugal force is treated, even by our best writers. As would then +naturally be expected, the definitions of it commonly found in our +handbooks are generally indefinite, or misleading, or even absolutely +untrue. + +Before we can intelligently consider the principles and methods of +balancing this force, we must get a correct conception of the nature of +the force itself. What, then, is centrifugal force? It is an extremely +simple thing; a very ordinary amount of mechanical intelligence is +sufficient to enable one to form a correct and clear idea of it. This +fact renders it all the more surprising that such inaccurate and +confused language should be employed in its definition. Respecting +writers, also, who use language with precision, and who are profound +masters of this subject, it must be said that, if it had been their +purpose to shroud centrifugal force in mystery, they could hardly have +accomplished this purpose more effectually than they have done, to minds +by whom it was not already well understood. + +Let us suppose a body to be moving in a circular path, around a center +to which it is firmly held; and let us, moreover, suppose the impelling +force, by which the body was put in motion, to have ceased; and, also, +that the body encounters no resistance to its motion. It is then, by our +supposition, moving in its circular path with a uniform velocity, +neither accelerated nor retarded. Under these conditions, what is the +force which is being exerted on this body? Clearly, there is only one +such force, and that is, the force which holds it to the center, and +compels it, in its uniform motion, to maintain a fixed distance from +this center. This is what is termed centripetal force. It is obvious, +that the centripetal force, which holds this revolving body _to_ the +center, is the only force which is being exerted upon it. + +Where, then, is the centrifugal force? Why, the fact is, there is not +any such thing. In the dynamical sense of the term "force," the sense in +which this term is always understood in ordinary speech, as something +tending to produce motion, and the direction of which determines the +direction in which motion of a body must take place, there is, I repeat, +no such thing as centrifugal force. + +There is, however, another sense in which the term "force" is employed, +which, in distinction from the above, is termed a statical sense. This +"statical force" is the force by the exertion of which a body keeps +still. It is the force of inertia--the resistance which all matter +opposes to a dynamical force exerted to put it in motion. This is the +sense in which the term "force" is employed in the expression +"centrifugal force." Is that all? you ask. Yes; that is all. + +I must explain to you how it is that a revolving body exerts this +resistance to being put in motion, when all the while it _is_ in motion, +with, according to our above supposition, a uniform velocity. The first +law of motion, so far as we now have occasion to employ it, is that a +body, when put in motion, moves in a straight line. This a moving body +always does, unless it is acted on by some force, other than its +impelling force, which deflects it, or turns it aside, from its direct +line of motion. A familiar example of this deflecting force is afforded +by the force of gravity, as it acts on a projectile. The projectile, +discharged at any angle of elevation, would move on in a straight line +forever, but, first, it is constantly retarded by the resistance of the +atmosphere, and, second, it is constantly drawn downward, or made to +fall, by the attraction of the earth; and so instead of a straight line +it describes a curve, known as the trajectory. + +Now a revolving body, also, has the same tendency to move in a straight +line. It would do so, if it were not continually deflected from this +line. Another force is constantly exerted upon it, compelling it, at +every successive point of its path, to leave the direct line of motion, +and move on a line which is everywhere equally distant from the center +to which it is held. If at any point the revolving body could get free, +and sometimes it does get free, it would move straight on, in a line +tangent to the circle at the point of its liberation. But if it cannot +get free, it is compelled to leave each new tangential direction, as +soon as it has taken it. + +This is illustrated in the above figure. The body, A, is supposed to be +revolving in the direction indicated by the arrow, in the circle, A B F +G, around the center, O, to which it is held by the cord, O A. At the +point, A, it is moving in the tangential direction, A D. It would +continue to move in this direction, did not the cord, O A, compel it to +move in the arc, A C. Should this cord break at the point, A, the body +would move; straight on toward D, with whatever velocity it had. + +You perceive now what centrifugal force is. This body is moving in the +direction, A D. The centripetal force, exerted through the cord, O A, +pulls it aside from this direction of motion. The body resists this +deflection, and this resistance is its centrifugal force. + +[Illustration: Fig. 1] + +Centrifugal force is, then, properly defined to be the disposition of a +revolving body to move in a straight line, and the resistance which such +a body opposes to being drawn aside from a straight line of motion. The +force which draws the revolving body continually to the center, or the +deflecting force, is called the centripetal force, and, aside from the +impelling and retarding forces which act in the direction of its motion, +the centripetal force is, dynamically speaking, the only force which is +exerted on the body. + +It is true, the resistance of the body furnishes the measure of the +centripetal force. That is, the centripetal force must be exerted in a +degree sufficient to overcome this resistance, if the body is to move in +the circular path. In this respect, however, this case does not differ +from every other case of the exertion of force. Force is always exerted +to overcome resistance: otherwise it could not be exerted. And the +resistance always furnishes the exact measure of the force. I wish to +make it entirely clear, that in the dynamical sense of the term "force," +there is no such thing as centrifugal force. The dynamical force, that +which produces motion, is the centripetal force, drawing the body +continually from the tangential direction, toward the center; and what +is termed centrifugal force is merely the resistance which the body +opposes to this deflection, _precisely like any other resistance to a +force_. + +The centripetal force is exerted on the radial line, as on the line, A +O, Fig. 1, at right angles with the direction in which the body is +moving; and draws it directly toward the center. It is, therefore, +necessary that the resistance to this force shall also be exerted on the +same line, in the opposite direction, or directly from the center. But +this resistance has not the least power or tendency to produce motion in +the direction in which it is exerted, any more than any other resistance +has. + +We have been supposing a body to be firmly held to the center, so as to +be compelled to revolve about it in a fixed path. But the bond which +holds it to the center may be elastic, and in that case, if the +centrifugal force is sufficient, the body will be drawn from the center, +stretching the elastic bond. It may be asked if this does not show +centrifugal force to be a force tending to produce motion from the +center. This question is answered by describing the action which really +takes place. The revolving body is now imperfectly deflected. The bond +is not strong enough to compel it to leave its direct line of motion, +and so it advances a certain distance along this tangential line. This +advance brings the body into a larger circle, and by this enlargement of +the circle, assuming the rate of revolution to be maintained, its +centrifugal force is proportionately increased. The deflecting power +exerted by the elastic bond is also increased by its elongation. If this +increase of deflecting force is no greater than the increase of +centrifugal force, then the body will continue on in its direct path; +and when the limit of its elasticity is reached, the deflecting bond +will be broken. If, however, the strength of the deflecting bond is +increased by its elongation in a more rapid ratio than the centrifugal +force is increased by the enlargement of the circle, then a point will +be reached in which the centripetal force will be sufficient to compel +the body to move again in the circular path. + +Sometimes the centripetal force is weak, and opportunity is afforded to +observe this action, and see its character exhibited. A common example +of weak centripetal force is the adhesion of water to the face of a +revolving grindstone. Here we see the deflecting force to become +insufficient to compel the drops of water longer to leave their direct +paths, and so these do not longer leave their direct paths, but move on +in those paths, with the velocity they have at the instant of leaving +the stone, flying off on tangential lines. + +If, however, a fluid be poured on the side of the revolving wheel near +the axis, it will move out to the rim on radial lines, as may be +observed on car wheels universally. The radial lines of black oil on +these wheels look very much as if centrifugal force actually did produce +motion, or had at least a very decided tendency to produce motion, in +the radial direction. This interesting action calls for explanation. In +this action the oil moves outward gradually, or by inconceivably minute +steps. Its adhesion being overcome in the least possible degree, it +moves in the same degree tangentially. In so doing it comes in contact +with a point of the surface which has a motion more rapid than its own. +Its inertia has now to be overcome, in the same degree in which it had +overcome the adhesion. Motion in the radial direction is the result of +these two actions, namely, leaving the first point of contact +tangentially and receiving an acceleration of its motion, so that this +shall be equal to that of the second point of contact. When we think +about the matter a little closely, we see that at the rim of the wheel +the oil has perhaps ten times the velocity of revolution which it had on +leaving the journal, and that the mystery to be explained really is, How +did it get that velocity, moving out on a radial line? Why was it not +left behind at the very first? Solely by reason of its forward +tangential motion. That is the answer. + +When writers who understand the subject talk about the centripetal and +centrifugal forces being different names for the same force, and about +equal action and reaction, and employ other confusing expressions, just +remember that all they really mean is to express the universal relation +between force and resistance. The expression "centrifugal force" is +itself so misleading, that it becomes especially important that the real +nature of this so-called force, or the sense in which the term "force" +is used in this expression, should be fully explained.[1] This force is +now seen to be merely the tendency of a revolving body to move in a +straight line, and the resistance which it opposes to being drawn aside +from that line. Simple enough! But when we come to consider this action +carefully, it is wonderful how much we find to be contained in what +appears so simple. Let us see. + +[Footnote 1: I was led to study this subject in looking to see what had +become of my first permanent investment, a small venture, made about +thirty-five years ago, in the "Sawyer and Gwynne static pressure +engine." This was the high-sounding name of the Keely motor of that day, +an imposition made possible by the confused ideas prevalent on this very +subject of centrifugal force.] + +FIRST.--I have called your attention to the fact that the direction in +which the revolving body is deflected from the tangential line of motion +is toward the center, on the radial line, which forms a right angle with +the tangent on which the body is moving. The first question that +presents itself is this: What is the measure or amount of this +deflection? The answer is, this measure or amount is the versed sine of +the angle through which the body moves. + +Now, I suspect that some of you--some of those whom I am directly +addressing--may not know what the versed sine of an angle is; so I must +tell you. We will refer again to Fig. 1. In this figure, O A is one +radius of the circle in which the body A is revolving. O C is another +radius of this circle. These two radii include between them the angle A +O C. This angle is subtended by the arc A C. If from the point O we let +fall the line C E perpendicular to the radius O A, this line will divide +the radius O A into two parts, O E and E A. Now we have the three +interior lines, or the three lines within the circle, which are +fundamental in trigonometry. C E is the sine, O E is the cosine, and E A +is the versed sine of the angle A O C. Respecting these three lines +there are many things to be observed. I will call your attention to the +following only: + +_First_.--Their length is always less than the radius. The radius is +expressed by 1, or unity. So, these lines being less than unity, their +length is always expressed by decimals, which mean equal to such a +proportion of the radius. + +_Second_.--The cosine and the versed sine are together equal to the +radius, so that the versed sine is always 1, less the cosine. + +_Third_.--If I diminish the angle A O C, by moving the radius O C toward +O A, the sine C E diminishes rapidly, and the versed sine E A also +diminishes, but more slowly, while the cosine O E increases. This you +will see represented in the smaller angles shown in Fig. 2. If, finally, +I make O C to coincide with O A, the angle is obliterated, the sine and +the versed sine have both disappeared, and the cosine has become the +radius. + +_Fourth_.--If, on the contrary, I enlarge the angle A O C by moving the +radius O C toward O B, then the sine and the versed sine both increase, +and the cosine diminishes; and if, finally, I make O C coincide with O +B, then the cosine has disappeared, the sine has become the radius O B, +and the versed sine has become the radius O A, thus forming the two +sides inclosing the right angle A O B. The study of this explanation +will make you familiar with these important lines. The sine and the +cosine I shall have occasion to employ in the latter part of my lecture. +Now you know what the versed sine of an angle is, and are able to +observe in Fig. 1 that the versed sine A E, of the angle A O C, +represents in a general way the distance that the body A will be +deflected from the tangent A D toward the center O while describing the +arc A C. + +The same law of deflection is shown, in smaller angles, in Fig. 2. In +this figure, also, you observe in each of the angles A O B and A O C +that the deflection, from the tangential direction toward the center, of +a body moving in the arc A C is represented by the versed sine of the +angle. The tangent to the arc at A, from which this deflection is +measured, is omitted in this figure to avoid confusion. It is shown +sufficiently in Fig. 1. The angles in Fig. 2 are still pretty large +angles, being 12 deg. and 24 deg. respectively. These large angles are used for +convenience of illustration; but it should be explained that this law +does not really hold in them, as is evident, because the arc is longer +than the tangent to which it would be connected by a line parallel with +the versed sine. The law is absolutely true only when the tangent and +arc coincide, and approximately so for exceedingly small angles. + +[Illustration: Fig. 2] + +In reality, however, we have only to do with the case in which the arc +and the tangent do coincide, and in which the law that the deflection is +_equal to_ the versed sine of the angle is absolutely true. Here, in +observing this most familiar thing, we are, at a single step, taken to +that which is utterly beyond our comprehension. The angles we have to +consider disappear, not only from our sight, but even from our +conception. As in every other case when we push a physical investigation +to its limit, so here also, we find our power of thought transcended, +and ourselves in the presence of the infinite. + +We can discuss very small angles. We talk familiarly about the angle +which is subtended by 1" of arc. On Fig. 2, a short line is drawn near +to the radius O A'. The distance between O A' and this short line is 1 deg. +of the arc A' B'. If we divide this distance by 3,600, we get 1" of arc. +The upper line of the Table of versed sines given below is the versed +sine of 1" of arc. It takes 1,296,000 of these angles to fill a circular +space. These are a great many angles, but they do not make a circle. +They make a polygon. If the radius of the circumscribed circle of this +polygon is 1,296,000 feet, which is nearly 213 geographical miles, each +one of its sides will be a straight line, 6.283 feet long. On the +surface of the earth, at the equator, each side of this polygon would be +one-sixtieth of a geographical mile, or 101.46 feet. On the orbit of the +moon, at its mean distance from the earth, each of these straight sides +would be about 6,000 feet long. + +The best we are able to do is to conceive of a polygon having an +infinite number of sides, and so an infinite number of angles, the +versed sines of which are infinitely small, and having, also, an +infinite number of tangential directions, in which the body can +successively move. Still, we have not reached the circle. We never can +reach the circle. When you swing a sling around your head, and feel the +uniform stress exerted on your hand through the cord, you are made aware +of an action which is entirely beyond the grasp of our minds and the +reach of our analysis. + +So always in practical operation that law is absolutely true which we +observe to be approximated to more and more nearly as we consider +smaller and smaller angles, that the versed sine of the angle is the +measure of its deflection from the straight line of motion, or the +measure of its fall toward the center, which takes place at every point +in the motion of a revolving body. + +Then, assuming the absolute truth of this law of deflection, we find +ourselves able to explain all the phenomena of centrifugal force, and to +compute its amount correctly in all cases. + +We have now advanced two steps. We have learned _the direction_ and _the +measure_ of the deflection, which a revolving body continually suffers, +and its resistance to which is termed centrifugal force. The direction +is toward the center, and the measure is the versed sine of the angle. + +SECOND.--We next come to consider what are known as the laws of +centrifugal force. These laws are four in number. They are, that the +amount of centrifugal force exerted by a revolving body varies in four +ways. + +_First_.--Directly as the weight of the body. + +_Second_.--In a given circle of revolution, as the square of the speed +or of the number of revolutions per minute; which two expressions in +this case mean the same thing. + +_Third_.--With a given number of revolutions per minute, or a given +angular velocity[1] _directly_ as the radius of the circle; and + +_Fourth_.--With a given actual velocity, or speed in feet per minute, +_inversely_ as the radius of the circle. + +[Footnote 1: A revolving body is said to have the same angular velocity, +when it sweeps through equal angles in equal times. Its actual velocity +varies directly as the radius of the circle in which it is revolving.] + +Of course there is a reason for these laws. You are not to learn them by +rote, or to accept them on any authority. You are taught not to accept +any rule or formula on authority, but to demand the reason for it--to +give yourselves no rest until you know the why and wherefore, and +comprehend these fully. This is education, not cramming the mind with +mere facts and rules to be memorized, but drawing out the mental powers +into activity, strengthening them by use and exercise, and forming the +habit, and at the same time developing the power, of penetrating to the +reason of things. + +In this way only, you will be able to meet the requirement of a great +educator, who said: "I do not care to be told what a young man knows, +but what he can _do_." I wish here to add my grain to the weight of +instruction which you receive, line upon line, precept on precept, on +this subject. + +The reason for these laws of centrifugal force is an extremely simple +one. The first law, that this force varies directly as the weight of the +body, is of course obvious. We need not refer to this law any further. +The second, third, and fourth laws merely express the relative rates at +which a revolving body is deflected from the tangential direction of +motion, in each of the three cases described, and which cases embrace +all possible conditions. + +These three rates of deflection are exhibited in Fig. 2. An examination +of this figure will give you a clear understanding of them. Let us first +suppose a body to be revolving about the point, O, as a center, in a +circle of which A B C is an arc, and with a velocity which will carry it +from A to B in one second of time. Then in this time the body is +deflected from the tangential direction a distance equal to A D, the +versed sine of the angle A O B. Now let us suppose the velocity of this +body to be doubled in the same circle. In one second of time it moves +from A to C, and is deflected from the tangential direction of motion a +distance equal to A E, the versed sine of the angle, A O C. But A E is +four times A D. Here we see in a given circle of revolution the +deflection varying as the square of the speed. The slight error already +pointed out in these large angles is disregarded. + +The following table will show, by comparison of the versed sines of very +small angles, the deflection in a given circle varying as the square of +the speed, when we penetrate to them, so nearly that the error is not +disclosed at the fifteenth place of decimals. + + The versed sine of 1" is 0.000,000,000,011,752 + " " " " 2" is 0.000,000,000,047,008 + " " " " 3" is 0.000,000,000,105,768 + " " " " 4" is 0.000,000,000,188,032 + " " " " 5" is 0.000,000,000,293,805 + " " " " 6" is 0.000,000,000,423,072 + " " " " 7" is 0.000,000,000,575,848 + " " " " 8" is 0.000,000,000,752,128 + " " " " 9" is 0.000,000,000,951,912 + " " " " 10" is 0.000,000,001,175,222 + " " " " 100" is 0.000,000,117,522,250 + +You observe the deflection for 10" of arc is 100 times as great, and for +100" of arc is 10,000 times as great as it is for 1" of arc. So far as +is shown by the 15th place of decimals, the versed sine varies as the +square of the angle; or, in a given circle, the deflection, and so the +centrifugal force, of a revolving body varies as the square of the +speed. + +The reason for the third law is equally apparent on inspection of Fig. +2. It is obvious, that in the case of bodies making the same number of +revolutions in different circles, the deflection must vary directly as +the diameter of the circle, because for any given angle the versed sine +varies directly as the radius. Thus radius O A' is twice radius O A, and +so the versed sine of the arc A' B' is twice the versed sine of the arc +A B. Here, while the angular velocity is the same, the actual velocity +is doubled by increase in the diameter of the circle, and so the +deflection is doubled. This exhibits the general law, that with a given +angular velocity the centrifugal force varies directly as the radius or +diameter of the circle. + +We come now to the reason for the fourth law, that, with a given actual +velocity, the centrifugal force varies _inversely_ as the diameter of +the circle. If any of you ever revolved a weight at the end of a cord +with some velocity, and let the cord wind up, suppose around your hand, +without doing anything to accelerate the motion, then, while the circle +of revolution was growing smaller, the actual velocity continuing nearly +uniform, you have felt the continually increasing stress, and have +observed the increasing angular velocity, the two obviously increasing +in the same ratio. That is the operation or action which the fourth law +of centrifugal force expresses. An examination of this same figure (Fig. +2) will show you at once the reason for it in the increasing deflection +which the body suffers, as its circle of revolution is contracted. If we +take the velocity A' B', double the velocity A B, and transfer it to the +smaller circle, we have the velocity A C. But the deflection has been +increasing as we have reduced the circle, and now with one half the +radius it is twice as great. It has increased in the same ratio in which +the angular velocity has increased. Thus we see the simple and necessary +nature of these laws. They merely express the different rates of +deflection of a revolving body in these different cases. + +THIRD.--We have a coefficient of centrifugal force, by which we are +enabled to compute the amount of this resistance of a revolving body to +deflection from a direct line of motion in all cases. This is that +coefficient. The centrifugal force of a body making _one_ revolution per +minute, in a circle of _one_ foot radius, is 0.000341 of the weight of +the body. + +According to the above laws, we have only to multiply this coefficient +by the square of the number of revolutions made by the body per minute, +and this product by the radius of the circle in feet, or in decimals of +a foot, and we have the centrifugal force, in terms of the weight of the +body. Multiplying this by the weight of the body in pounds, we have the +centrifugal force in pounds. + +Of course you want to know how this coefficient has been found out, and +how you can be sure it is correct. I will tell you a very simple way. +There are also mathematical methods of ascertaining this coefficient, +which your professors, if you ask them, will let you dig out for +yourselves. The way I am going to tell you I found out for myself, and +that, I assure you, is the only way to learn anything, so that it will +stick; and the more trouble the search gives you, the darker the way +seems, and the greater the degree of perseverance that is demanded, the +more you will appreciate the truth when you have found it, and the more +complete and permanent your possession of it will be. + +The explanation of this method may be a little more abstruse than the +explanations already given, but it is very simple and elegant when you +see it, and I fancy I can make it quite clear. I shall have to preface +it by the explanation of two simple laws. The first of these is, that a +body acted on by a constant force, so as to have its motion uniformly +accelerated, suppose in a straight line, moves through distances which +increase as the square of the time that the accelerating force continues +to be exerted. + +The necessary nature of this law, or rather the action of which this law +is the expression, is shown in Fig. 3. + +[Illustration: Fig. 3] + +Let the distances A B, B C, C D, and D E in this figure represent four +successive seconds of time. They may just as well be conceived to +represent any other equal units, however small. Seconds are taken only +for convenience. At the commencement of the first second, let a body +start from a state of rest at A, under the action of a constant force, +sufficient to move it in one second through a distance of one foot. This +distance also is taken only for convenience. At the end of this second, +the body will have acquired a velocity of two feet per second. This is +obvious because, in order to move through one foot in this second, the +body must have had during the second an average velocity of one foot per +second. But at the commencement of the second it had no velocity. Its +motion increased uniformly. Therefore, at the termination of the second +its velocity must have reached two feet per second. Let the triangle A B +F represent this accelerated motion, and the distance, of one foot, +moved through during the first second, and let the line B F represent +the velocity of two feet per second, acquired by the body at the end of +it. Now let us imagine the action of the accelerating force suddenly to +cease, and the body to move on merely with the velocity it has acquired. +During the next second it will move through two feet, as represented by +the square B F C I. But in fact, the action of the accelerating force +does not cease. This force continues to be exerted, and produces on the +body during the next second the same effect that it did during the first +second, causing it to move through an additional foot of distance, +represented by the triangle F I G, and to have its velocity accelerated +two additional feet per second, as represented by the line I G. So in +two seconds the body has moved through four feet. We may follow the +operation of this law as far as we choose. The figure shows it during +four seconds, or any other unit, of time, and also for any unit of +distance. Thus: + + Time 1 Distance 1 + " 2 " 4 + " 3 " 9 + " 4 " 16 + +So it is obvious that the distance moved through by a body whose motion +is uniformly accelerated increases as the square of the time. + +But, you are asking, what has all this to do with a revolving body? As +soon as your minds can be started from a state of rest, you will +perceive that it has everything to do with a revolving body. The +centripetal force, which acts upon a revolving body to draw it to the +center, is a constant force, and under it the revolving body must move +or be deflected through distances which increase as the squares of the +times, just as any body must do when acted on by a constant force. To +prove that a revolving body obeys this law, I have only to draw your +attention to Fig. 2. Let the equal arcs, A B and B C, in this figure +represent now equal times, as they will do in case of a body revolving +in this circle with a uniform velocity. The versed sines of the angles, +A O B and A O C, show that in the time, A C, the revolving body was +deflected four times as far from the tangent to the circle at A as it +was in the time, A B. So the deflection increased as the square of the +time. If on the table already given, we take the seconds of arc to +represent equal times, we see the versed sine, or the amount of +deflection of a revolving body, to increase, in these minute angles, +absolutely so far as appears up to the fifteenth place of decimals, as +the square of the time. + +The standard from which all computations are made of the distances +passed through in given times by bodies whose motion is uniformly +accelerated, and from which the velocity acquired is computed when the +accelerating force is known, and the force is found when the velocity +acquired or the rate of acceleration is known, is the velocity of a body +falling to the earth. It has been established by experiment, that in +this latitude near the level of the sea, a falling body in one second +falls through a distance of 16.083 feet, and acquires a velocity of +32.166 feet per second; or, rather, that it would do so if it did not +meet the resistance of the atmosphere. In the case of a falling body, +its weight furnishes, first, the inertia, or the resistance to motion, +that has to be overcome, and affords the measure of this resistance, +and, second, it furnishes the measure of the attraction of the earth, or +the force exerted to overcome its resistance. Here, as in all possible +cases, the force and the resistance are identical with each other. The +above is, therefore, found in this way to be the rate at which the +motion of any body will be accelerated when it is acted on by a constant +force equal to its weight, and encounters no resistance. + +It follows that a revolving body, when moving uniformly in any circle at +a speed at which its deflection from a straight line of motion is such +that in one second this would amount to 16.083 feet, requires the +exertion of a centripetal force equal to its weight to produce such +deflection. The deflection varying as the square of the time, in 0.01 of +a second this deflection will be through a distance of 0.0016083 of a +foot. + +Now, at what speed must a body revolve, in a circle of one foot radius, +in order that in 0.01 of one second of time its deflection from a +tangential direction shall be 0.0016083 of a foot? This decimal is the +versed sine of the arc of 3 deg.15', or of 3.25 deg.. This angle is so small +that the departure from the law that the deflection is equal to the +versed sine of the angle is too slight to appear in our computation. +Therefore, the arc of 3.25 deg. is the arc of a circle of one foot radius +through which a body must revolve in 0.01 of a second of time, in order +that the centripetal force, and so the centrifugal force, shall be equal +to its weight. At this rate of revolution, in one second the body will +revolve through 325 deg., which is at the rate of 54.166 revolutions per +minute. + +Now there remains only one question more to be answered. If at 54.166 +revolutions per minute the centrifugal force of a body is equal to its +weight, what will its centrifugal force be at one revolution per minute +in the same circle? + +To answer this question we have to employ the other extremely simple +law, which I said I must explain to you. It is this: The acceleration +and the force vary in a constant ratio with each other. Thus, let force +1 produce acceleration 1, then force 1 applied again will produce +acceleration 1 again, or, in other words, force 2 will produce +acceleration 2, and so on. This being so, and the amount of the +deflection varying as the squares of the speeds in the two cases, the +centrifugal force of a body making one revolution per minute in a circle +of + + 1 squared + one foot radius will be ---------- = 0.000341 + 54.166 squared + +--the coefficient of centrifugal force. + +There is another mode of making this computation, which is rather neater +and more expeditious than the above. A body making one revolution per +minute in a circle of one foot radius will in one second revolve through +an arc of 6 deg.. The versed sine of this arc of 6 deg. is 0.0054781046 of a +foot. This is, therefore, the distance through which a body revolving at +this rate will be deflected in one second. If it were acted on by a +force equal to its weight, it would be deflected through the distance of +16.083 feet in the same time. What is the deflecting force actually +exerted upon it? Of + + 0.0054781046 +course, it is ------------. + 16.083 + +This division gives 0.000341 of its weight as such deflecting force, the +same as before. + +In taking the versed sine of 6 deg., a minute error is involved, though not +one large enough to change the last figure in the above quotient. The +law of uniform acceleration does not quite hold when we come to an angle +so large as 6 deg.. If closer accuracy is demanded, we can attain it, by +taking the versed sine for 1 deg., and multiplying this by 6 squared. This gives as +a product 0.0054829728, which is a little larger than the versed sine of +6 deg.. + +I hope I have now kept my promise, and made it clear how the coefficient +of centrifugal force may be found in this simple way. + +We have now learned several things about centrifugal force. Let me +recapitulate. We have learned: + +1st. The real nature of centrifugal force. That in the dynamical sense +of the term force, this is not a force at all: that it is not capable of +producing motion, that the force which is really exerted on a revolving +body is the centripetal force, and what we are taught to call +centrifugal force is nothing but the resistance which a revolving body +opposes to this force, precisely like any other resistance. + +2d. The direction of the deflection, to which the centrifugal force is +the resistance, which is straight to the center. + +3d. The measure of this deflection; the versed sine of the angle. + +4th. The reason of the laws of centrifugal force; that these laws merely +express the relative amount of the deflection, and so the amount of the +force required to produce the deflection, and of the resistance of the +revolving body to it, in all different cases. + +5th. That the deflection of a revolving body presents a case analogous +to that of uniformly accelerated motion, under the action of a constant +force, similar to that which is presented by falling bodies;[1] and +finally, + +6th. How to find the coefficient, by which the amount of centrifugal +force exerted in any case may be computed. + +[Footnote 1: A body revolving with a uniform velocity in a horizontal +plane would present the only case of uniformly accelerated motion that +is possible to be realized under actual conditions.] + +I now pass to some other features. + +_First_.--You will observe that, relatively to the center, a revolving +body, at any point in its revolution, is at rest. That is, it has no +motion, either from or toward the center, except that which is produced +by the action of the centripetal force. It has, therefore, this identity +also with a falling body, that it starts from a state of rest. This +brings us to a far more comprehensive definition of centrifugal force. +This is the resistance which a body opposes to being put in motion, at +any velocity acquired in any time, from a state of rest. Thus +centrifugal force reveals to us the measure of the inertia of matter. +This inertia may be demonstrated and exhibited by means of apparatus +constructed on this principle quite as accurately as it can be in any +other way. + +_Second_.--You will also observe the fact, that motion must be imparted +to a body gradually. As distance, _through_ which force can act, is +necessary to the impartation of velocity, so also time, _during_ which +force can act, is necessary to the same result. We do not know how +motion from a state of rest begins, any more than we know how a polygon +becomes a circle. But we do know that infinite force cannot impart +absolutely instantaneous motion to even the smallest body, or to a body +capable of opposing the least resistance. Time being an essential +element or factor in the impartation of velocity, if this factor be +omitted, the least resistance becomes infinite. + +We have a practical illustration of this truth in the explosion of +nitro-glycerine. If a small portion of this compound be exploded on the +surface of a granite bowlder, in the open air, the bowlder will be rent +into fragments. The explanation of this phenomenon common among the +laborers who are the most numerous witnesses of it, which you have +doubtless often heard, and which is accepted by ignorant minds without +further thought, is that the action of nitro-glycerine is downward. We +know that such an idea is absurd. + +The explosive force must be exerted in all directions equally. The real +explanation is, that the explosive action of nitro-glycerine is so +nearly instantaneous, that the resistance of the atmosphere is very +nearly equal to that of the rock; at any rate, is sufficient to cause +the rock to be broken up. The rock yields to the force very nearly as +readily as the atmosphere does. + +_Third_. An interesting solution is presented here of what is to many an +astronomical puzzle. When I was younger than I am now, I was greatly +troubled to understand how it could be that if the moon was always +falling to the earth, as the astronomers assured us it was, it should +never reach it, nor have its falling velocity accelerated. In popular +treatises on astronomy, such for example as that of Professor Newcomb, +this is explained by a diagram in which the tangential line is carried +out as in Fig. 1, and by showing that in falling from the point A to the +earth as a center, through distances increasing as the square of the +time, the moon, having the tangential velocity that it has, could never +get nearer to the earth than the circle in which it revolves around it. +This is all very true, and very unsatisfactory. We know that this long +tangential line has nothing to do with the motion of the moon, and while +we are compelled to assent to the demonstration, we want something +better. To my mind the better and more satisfactory explanation is found +in the fact that the moon is forever commencing to fall, and is +continually beginning to fall in a new direction. A revolving body, as +we have seen, never gets past that point, which is entirely beyond our +sight and our comprehension, of beginning to fall, before the direction +of its fall is changed. So, under the attraction of the earth, the moon +is forever leaving a new tangential direction of motion at the same +rate, without acceleration. + +(_To be continued_.) + + * * * * * + + + + +COMPRESSED AIR POWER SCHEMES. + +By J. STURGEON, Engineer of the Birmingham Compressed Air Power Company. + + +In the article on "Gas, Air, and Water Power" in the _Journal_ for Dec. +8 last, you state that you await with some curiosity my reply to certain +points in reference to the compressed air power schemes alluded to in +that article. I now, therefore, take the liberty of submitting to you +the arguments on my side of the question (which are substantially the +same as those I am submitting to Mr. Hewson, the Borough Engineer of +Leeds). The details and estimates for the Leeds scheme are not yet in a +forward enough state to enable me to give them at present; but the whole +case is sufficiently worked out for Birmingham to enable a fair +deduction to be made therefrom as regards the utility of the system in +other towns. In Birmingham, progress has been delayed owing to +difficulties in procuring a site for the works, and other matters of +detail. We have, however, recently succeeded in obtaining a suitable +place, and making arrangements for railway siding, water supply, etc.; +and we hope to be in a position to start early in the present year. + +I inclose (1) a tabulated summary of the estimates for Birmingham +divided into stages of 3,000 gross indicated horse power at a time; (2) +a statement showing the cost to consumers in terms of indicated horse +power and in different modes, more or less economical, of applying the +air power in the consumers' engines; (3) a tracing showing the method of +laying the mains; (4) a tracing showing the method of collecting the +meter records at the central station, by means of electric apparatus, +and ascertaining the exact amount of leakage. A short description of the +two latter would be as well. + +TABLE I.--_Showing the Progressive Development of the Compressed Air +System in stages of 3000 Indicated Horse Power (gross) at a Time, and +the Profits at each Stage_ + +_____________________________________________________________________________ + +Gross | 3000 | 6000 | 9000 | 12,000 | 15,000 | +Indicated | Ind. | Ind. | Ind. | Ind. | Ind. | +Horse Power | H.P. | H.P. | H.P. | H.P. | H.P. | +at Central | | | | | | +Works: | | | | | | +----------------------------------------------------------------------------- + +Thousands of | 1,080,000 | 2,160,000 |3,240,000 | 4,320,000 |5,400,000 | +Cubic Feet at 45 | | | | | | +lbs. pressure | | | | | | +at engines | | | | | | +Deduction for | 17,928 | 70,927 | 154,429 | 267,529 | 409,346 | +friction and | | | | | | +leakage | | | | | | +Estimated net | 1,062,072 | 2,089,073 |3,085,571 | 4,052,471 |4,990,654 | +delivery | | | | | | +----------------------------------------------------------------------------- + +CAPITAL | | | | | | +EXPENDITURE-- | | | | | | +Purchase and pre-| L12,500 | (amounts below apply to extension of works) | +paration of land | | | | | | +Machinery | 27,854 | L25,595 | L25,595 | L25,595 | L25,595 | +Mains | 10,328 | 10.328 | 10,328 | 10,328 | 10,328 | +Buildings | 8,505 | 4,516 | 4,632 | 4,614 | 4,594 | +Parlimentary and | | | | | | +general expenses,| 20,000 | .. | .. | .. | .. | +royalty, &c. | | | | | | +Engineering | 3,268 | 1,820 | 1,825 | 1,824 | 8,823 | + Previous Capit-| | 82,455 | 124,714 | 167,094 | 209,455 | + al Expenditure | .. | | | | | +Total Cap. Exp. | L82,455 | L124,714 | L167,094 | L209,455 | L251,795 | +----------------------------------------------------------------------------- + +ANNUAL CHARGES-- | | | | | | +Salaries, wages, | | | | | | +& general working| L6,405 | L7,855 | L9,305 | L10,955 | L12,480 | + expenses | | | | | | +Repairs, renewals| 2,780 | 5,198 | 7,622 | 10,045 | 12,467 | +&c.(reserve fund)| | | | | | +Coal, water, &c. | 1,950 | 3,900 | 5,850 | 7,800 | 9,750 | +Rates | 370 | 674 | 980 | 1,285 | 1,585 | +Contingencies of | | | | | | +horse power = 5 | 575 | 881 | 1,187 | 1,504 | 1,814 | +per cent on above| | | | | | +Total Ann. Exp. | L12,080 | L18,508 | L24,944 | L31,589 | L38,096 | +----------------------------------------------------------------------------- + +Revenue at 5d. | | | | | | +per 1000 cub. ft.| 22,126 | 43,522 | 64,282 | 84,426 | 103,971 | +(average) | | | | | | +Profit |12.18 p.ct.|20.06 p.ct.|23.54 p.ct.|25.22 p.ct.|26.16 p.ct.| + |= 10,046 | = 25,014 | = 39,338 | = 52,837 | = 65,875 | +----------------------------------------------------------------------------- + +TABLE II.--_Cost of Air Power in Terms of Indicated Horse Power_. + +Abbreviated column headings: + +Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per +Hour. + +Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet. + +Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per +Cent. + +Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet. + +Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per +Cent. + +Abbreviated row headings: + +CASE 1.--Where air at 45 lbs. pressure is re-heated to 320 deg. Fahr., and +expanded to atmospheric pressure. + +CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to +212 deg. Fahr., and expanded to atmospheric pressure. + +CASE 3.--Where air is used expansively without re-heating, whereby +intensely cold air is exhausted, and may be used for ice making, &c. + +CASE 4.--Where air is heated to 212 deg. Fahr., and the terminal pressure is +11.3 lbs. above that of the atmosphere + +CASE 5.--Where the air is used without heating, and cut off at one-third +of the stroke, as in ordinary slide-valve engines + +CASE 6.--Where the air is used without re-heating and without expansion. + + _____________________________________________________________________ + | Qty. Air | Cost/Hr. | Cost/Hr. | Cost/Yr. | Cost/Yr. | + | | | w/rebate | | w/rebate | + | Cub. Ft. | d. | d. | L s. d. | L s. d.| + --------------------------------------------------------------------- + CASE 1 | 125.4 | 0.627 | 0.596 | 7 1 1 | 6 14 01/2| + CASE 2 | 140.4 | 0.702 | 0.667 | 7 17 11 | 7 10 0 | + CASE 3 | 178.2 | 0.891 | 0.847 | 10 0 51/2 | 9 10 51/2| + CASE 4 | 170.2 | 0.851 | 0.809 | 9 11 51/2 | 9 1 101/2| + CASE 5 | 258.0 | 1.290 | 1.226 | 14 10 3 | 13 15 9 | + CASE 6 | 331.8 | 1.659 | 1.576 | 18 13 3 | 17 14 7 | + _____________________________________________________________________ + +The great thing to guard against is leakage. If the pipes were simply +buried in the ground, it would be almost impossible to trace leakage, or +even to know of its existence. The income of the company might be +wasting away, and the loss never suspected until the quarterly returns +from the meters were obtained from the inspectors. Only then would it be +discovered that there must be a great leak (or it might be several +leaks) somewhere. But how would it be possible to trace them among 20 or +30 miles of buried pipes? We cannot break up the public streets. The +very existence of the concern depends upon (1) the _daily_ checking of +the meter returns, and comparison with the output from the air +compressors, so as to ascertain the amount of leakage; (2) facility for +tracing the locality of a leak; and (3) easy access to the mains with +the minimum of disturbance to the streets. It will be readily +understood, from the drawings, how this is effected. First, the pipes +are laid in concrete troughs, near the surface of the road, with +removable concrete covers strong enough to stand any overhead traffic. +At intervals there are junctions for service connections, with street +boxes and covers serving as inspection chambers. These chambers are also +provided over the ball-valves, which serve as stop-valves in case of +necessity, and are so arranged that in case of a serious breach in the +portion of main between any two of them, the rush of air to the breach +will blow them up to the corresponding seats and block off the broken +portion of main. The air space around the pipe in the concrete trough +will convey for a long distance the whistling noise of a leak; and the +inspectors, by listening at the inspection openings, will thus be +enabled to rapidly trace their way almost to the exact spot where there +is an escape. They have then only to remove the top surface of road +metal and the concrete cover in order to expose the pipe and get at the +breach. Leaks would mostly be found at joints; and, by measuring from +the nearest street opening, the inspectors would know where to break +open the road to arrive at the probable locality of the leak. A very +slight leak can be heard a long way off by its peculiar whistling sound. + +[Illustration: COMPRESSED AIR POWER] + +The next point is to obtain a daily report of the condition of the mains +and the amount of leakage. It would be impracticable to employ an army +of meter inspectors to take the records daily from all the meters in the +district. We therefore adopt the method of electric signaling shown in +the second drawing. In the engineer's office, at the central station, is +fixed the dial shown in Fig. 1. Each consumer's meter is fitted with the +contact-making apparatus shown in Pig. 4, and in an enlarged form in +Figs. 5 and 6, by which a current is sent round the electro-magnet, D +(Fig. 1), attracting the armature, and drawing the disk forward +sufficiently for the roller at I to pass over the center of one of the +pins, and so drop in between that and the next pin, thus completing the +motion, and holding the disk steadily opposite the figure. This action +takes place on any meter completing a unit of measurement of (say) 1,000 +cubic feet, at which point the contact makers touch. But suppose one +meter should be moving very slowly, and so retaining contact for some +time, while other meters were working rapidly; the armature at D would +then be held up to the magnet by the prolonged contact maintained by the +slow moving meter, and so prevent the quick working meters from +actuating it; and they would therefore pass the contact points without +recording. A meter might also stop dead at the point of contact on +shutting off the air, and so hold up the armature; thus preventing +others from acting. To obviate this, we apply the disengaging apparatus +shown at L (Fig. 4). The contact maker works on the center, m, having an +armature on its opposite end. On contact being made, at the same time +that the magnet, D, is operated, the one at L is also operated, +attracting the armature, and throwing over the end of the contact maker, +l, on to the non-conducting side of the pin on the disk. Thus the whole +movement is rendered practically instantaneous, and the magnet at D is +set at liberty for the next operation. A resistance can be interposed at +L, if necessary, to regulate the period of the operation. The whole of +the meters work the common dial shown in Fig. 1, on which the gross +results only are recorded; and this is all we want to know in this way. +The action is so rapid, owing to the use of the magnetic disengaging +gear, that the chances of two or more meters making contact at the same +moment are rendered extremely small. Should such a thing happen, it +would not matter, as it is only approximate results that we require in +this case; and the error, if any, would add to the apparent amount of +leakage, and so be on the right side. Of course, the record of each +consumer's meter would be taken by the inspector at the end of every +quarter, in order to make out the bill; and the totals thus obtained +would be checked by the gross results indicated by the main dial. In +this way, by a comparison of these results, a coefficient would soon be +arrived at, by which the daily recorded results could be corrected to an +extremely accurate measurement. At the end of the working day, the +engineer has merely to take down from the dial in his office the total +record of air measured to the consumers, also the output of air from the +compressors, which he ascertains by means of a continuous counter on the +engines, and the difference between the two will represent the loss. If +the loss is trifling, he will pass it over; if serious, he will send out +his inspectors to trace it. Thus there could be no long continued +leakage, misuse, or robbery of the air, without the company becoming +aware of the fact, and so being enabled to take measures to stop or +prevent it. The foregoing are absolutely essential adjuncts to any +scheme of public motive power supply by compressed air, without which we +should be working in the dark, and could never be sure whether the +company were losing or making money. With them, we know where we are and +what we are doing. + +Referring to the estimates given in Table I., I may explain that the +item of repairs and renewals covers 10 per cent. on boilers and gas +producers, 5 per cent. on engines, 5 per cent. on buildings, and 5 per +cent. on mains. Considering that the estimates include ample fitting +shops, with the best and most suitable tools, and that the wages list +includes a staff of men whose chief work would be to attend to repairs, +etc., I think the above allowances ample. Each item also includes 5 per +cent. for contingencies. + +I have commenced by giving all the preceding detail, in order to show +the groundwork on which I base the estimate of the cost of compressed +air power to consumers, in terms of indicated horse power per annum, as +given in Table II. I may say that, in estimating the engine power and +coal consumption, I have not, as in the original report, made purely +theoretical calculations, but have taken diagrams from engines in actual +use (although of somewhat smaller size than those intended to be +employed), and have worked out the results therefrom. It will, I hope, +be seen that, with all the safeguards we have provided, we may fairly +reckon upon having for sale the stated quantity of air produced by means +of the plant, as estimated, and at the specified annual cost; and that +therefore the statement of cost per indicated horse power per annum may +be fairly relied upon. Thus the cost of compressed air to the consumer, +based upon an _average_ charge of 5d. per 1,000 cubic feet, will vary +from L6 14s. per indicated horse power per annum to L18 13s. 3d., +according to circumstances and mode of application. + +A compressed air motor is an exceedingly simple machine--much simpler +than an ordinary steam engine. But the air may also be used in an +ordinary steam engine; and in this case it can be much simplified in +many details. Very little packing is needed, as there is no nuisance +from gland leakage; the friction is therefore very slight. Pistons and +glands are packed with soapstone, or other self-lubricating packing; and +no oil is required except for bearings, etc. The company will undertake +the periodical inspection and overhauling of engines supplied with their +power, all which is included in the estimates. The total cost to +consumers, with air at an average of 5d. per 1,000 cubic feet, may +therefore be fairly taken as follows: + + Min. Max. + Cost of air used L6 14 01/2 L18 13 3 + Oil. waste, packing, etc. 1 0 0 1 0 0 + Interest, depreciation, + etc., 121/2 per cent. on + L10, the cost of engine + per indicated + horse power 1 5 0 1 5 0 + -------- --------- + L8 19 01/2 L20 18 3 + +The maximum case would apply only to direct acting engines, such as +Tangye pumps, air power hammers, etc., where the air is full on till the +end of the stroke, and where there is no expansion. The minimum given is +at the average rate of 5d. per 1,000 cubic feet; but as there will be +rates below this, according to a sliding scale, we may fairly take it +that the lowest charge will fall considerably below L6 per indicated +horse power per annum.--_Journal of Gas Lighting_. + + * * * * * + + + + +THE BERTHON COLLAPSIBLE CANOE. + + +An endeavor has often been made to construct a canoe that a person can +easily carry overland and put into the water without aid, and convert +into a sailboat. The system that we now call attention to is very well +contrived, very light, easily taken apart, and for some years past has +met with much favor. + +[Illustration: FIG. 1.--BERTHON COLLAPSIBLE CANOE AFLOAT.] + +Mr. Berthon's canoes are made of impervious oil-skin. Form is given them +by two stiff wooden gunwales which are held in position by struts that +can be easily put in and taken out. The model shown in the figure is +covered with oiled canvas, and is provided with a double paddle and a +small sail. Fig. 2 represents it collapsed and being carried overland. + +[Illustration: FIG. 2.--THE SAME BEING CARRIED OVERLAND.] + +Mr. Berthon is manufacturing a still simpler style, which is provided +with two oars, as in an ordinary canoe. This model, which is much used +in England by fishermen and hunters, has for several years past been +employed in the French navy, in connection with movable defenses. At +present, every torpedo boat carries one or two of these canoes, each +composed of two independent halves that may be put into the water +separately or be joined together by an iron rod. + +These boats ride the water very well, and are very valuable for +exploring quarters whither torpedo boats could not adventure without +danger.[1]--_La Nature_. + +[Footnote 1: For detailed description see SUPPLEMENT, No. 84.] + + * * * * * + + + + +THE FIFTIETH ANNIVERSARY OF THE OPENING OF THE FIRST GERMAN STEAM +RAILROAD. + + +There was great excitement in Nuernberg on the 7th of December, 1835, on +which day the first German railroad was opened. The great square on +which the buildings of the Nuernberg and Furth "Ludwig's Road" stood, the +neighboring streets, and, in fact, the whole road between the two +cities, was filled with a crowd of people who flocked from far and near +to see the wonderful spectacle. For the first time, a railroad train +filled with passengers was to be drawn from Nuernberg to Furth by the +invisible power of the steam horse. At eight o'clock in the morning, the +civil and military authorities, etc., who took part in the celebration +were assembled on the square, and the gayly decorated train started off +to an accompaniment of music, cannonading, cheering, etc. Everything +passed off without an accident; the work was a success. The engraving in +the lower right-hand corner represents the engine and cars of this road. + +It will be plainly seen that such a revolution could not be accomplished +easily, and that much sacrifice and energy were required of the leaders +in the enterprise, prominent among whom was the merchant Johannes +Scharrer, who is known as the founder of the "Ludwig's Road." + +One would naturally suppose that such an undertaking would have met with +encouragement from the Bavarian Government, but this was not the case. +The starters of the enterprise met with opposition on every side; much +was written against it, and many comic pictures were drawn showing +accidents which would probably occur on the much talked of road. Two of +these pictures are shown in the accompanying large engraving, taken from +the _Illustrirte Zeitung_. As shown in the center picture, right hand, +it was expected by the railway opponents that trains running on tracks +at right angles must necessarily come in collision. If anything happened +to the engine, the passengers would have to get out and push the cars, +as shown at the left. + +[Illustration: JUBILEE CELEBRATION OF THE FIFTIETH ANNIVERSARY OF THE +OPENING OF THE FIRST STEAM RAILWAY IN GERMANY--AT NURNBERG] + +Much difficulty was experienced in finding an engineer capable of +attending to the construction of the road; and at first it was thought +that it would be best to engage an Englishman, but finally Engineer +Denis, of Munich, was appointed. He had spent much time in England and +America studying the roads there, and carried on this work to the entire +satisfaction of the company. + +All materials for the road were, as far as possible, procured in +Germany; but the idea of building the engines and cars there had to be +given up, and, six weeks before the opening of the road, Geo. +Stephenson, of London, whose engine, Rocket, had won the first prize in +the competitive trials at Rainhill in 1829, delivered an engine of ten +horse power, which is still known in Nuernberg as "Der Englander." + +Fifty years have passed, and, as Johannes Scharrer predicted, the +Ludwig's Road has become a permanent institution, though it now forms +only a very small part of the network of railroads which covers every +portion of Germany. What changes have been made in railroads during +these fifty years! Compare the present locomotives with the one made by +Cugnot in 1770, shown in the upper left-hand cut, and with the work of +the pioneer Geo. Stephenson, who in 1825 constructed the first passenger +railroad in England, and who established a locomotive factory in +Newcastle in 1824. Geo. Stephenson was to his time what Mr. Borsig, +whose great works at Moabit now turn out from 200 to 250 locomotives a +year, is to our time. + +Truly, in this time there can be no better occasion for a celebration of +this kind than the fiftieth anniversary of the opening of the first +German railroad, which has lately been celebrated by Nuernberg and Furth. + +The lower left-hand view shows the locomotive De Witt Clinton, the third +one built in the United States for actual service, and the coaches. The +engine was built at the West Point Foundry, and was successfully tested +on the Mohawk and Hudson Railroad between Albany and Schenectady on Aug. +9, 1831. + + * * * * * + + + + +IMPROVED COAL ELEVATOR. + + +An illustration of a new coal elevator is herewith presented, which +presents advantages over any incline yet used, so that a short +description may be deemed interesting to those engaged in the coaling +and unloading of vessels. The pen sketch shows at a glance the +arrangement and space the elevator occupies, taking less ground to do +the same amount of work than any other mode heretofore adopted, and the +first cost of erecting is about the same as any other. + +When the expense of repairing damages caused by the ravages of winter is +taken into consideration, and no floats to pump out or tracks to wash +away, the advantages should be in favor of a substantial structure. + +The capacity of this hoist is to elevate 80,000 bushels in ten hours, at +less than one-half cent per bushel, and put coal in elevator, yard, or +shipping bins. + +[Illustration: IMPROVED COAL ELEVATOR.] + +The endless wire rope takes the cars out and returns them, dispensing +with the use of train riders. + +A floating elevator can distribute coal at any hatch on steam vessels, +as the coal has to be handled but once; the hoist depositing an empty +car where there is a loaded one in boat or barge, requiring no swing of +the vessel. + +Mr. J.R. Meredith, engineer, of Pittsburg, Pa., is the inventor and +builder, and has them in use in the U.S. engineering service.--_Coal +Trade Journal_. + + * * * * * + + + + +STEEL-MAKING LADLES. + + +The practice of carrying melted cast iron direct from the blast furnace +to the Siemens hearth or the Bessemer converter saves both money and +time. It has rendered necessary the construction of special plant in the +form of ladles of dimensions hitherto quite unknown. Messrs. Stevenson & +Co., of Preston, make the construction of these ladles a specialty, and +by their courtesy, says _The Engineer_, we are enabled to illustrate +four different types, each steel works manager, as is natural, +preferring his own design. Ladles are also required in steel foundry +work, and one of these for the Siemens-Martin process is illustrated by +Fig. 1. These ladles are made in sizes to take from five to fifteen ton +charges, or larger if required, and are mounted on a very strong +carriage with a backward and forward traversing motion, and tipping gear +for the ladle. The ladles are butt jointed, with internal cover strips, +and have a very strong band shrunk on hot about half way in the depth of +the ladle. This forms an abutment for supporting the ladle in the +gudgeon band, being secured to this last by latch bolts and cotters. The +gearing is made of cast steel, and there is a platform at one end for +the person operating the carriage or tipping the ladle. Stopper gear and +a handle are fitted to the ladles to regulate the flow of the molten +steel from the nozzle at the bottom. + +[Illustration: LADLES FOR CARRYING MOLTEN IRON AND STEEL.] + +Fig. 2 shows a Spiegel ladle, of the pattern used at Cyfarthfa. It +requires no description. Fig. 3 shows a tremendous ladle constructed for +the North-Eastern Steel Company, for carrying molten metal from the +blast furnace to the converter. It holds ten tons with ease. It is an +exceptionally strong structure. The carriage frame is constructed +throughout of 1 in. wrought-iron plated, and is made to suit the +ordinary 4 ft. 81/2 in. railway gauge. The axle boxes are cast iron, +fitted with gun-metal steps. The wheels are made of forged iron, with +steel tires and axles. The carriage is provided with strong oak buffers, +planks, and spring buffers; the drawbars also have helical compression +springs of the usual type. The ladle is built up of 1/2 in. wrought-iron +plates, butt jointed, and double riveted butt straps. The trunnions and +flange couplings are of cast steel. The tipping gear, clearly shown in +the engraving, consists of a worm and wheel, both of steel, which can be +fixed on either side of the ladle as may be desired. From this it will +be seen that Messrs. Stevenson & Co. have made a thoroughly strong +structure in every respect, and one, therefore, that will commend itself +to most steel makers. We understand that these carriages are made in +various designs and sizes to meet special requirements. Thus, Fig. 4 +shows one of different design, made for a steel works in the North. This +is also a large ladle. The carriage is supported on helical springs and +solid steel wheels. It will readily be understood that very great care +and honesty of purpose is required in making these structures. A +breakdown might any moment pour ten tons of molten metal on the ground, +with the most horrible results. + + * * * * * + + + + +APPARATUS FOR DEMONSTRATING THAT ELECTRICITY DEVELOPS ONLY ON THE +SURFACE OF CONDUCTORS. + + +Mr. K.L. Bauer, of Carlsruhe, has just constructed a very simple and +ingenious apparatus which permits of demonstrating that electricity +develops only on the surface of conductors. It consists (see figure) +essentially of a yellow-metal disk, M, fixed to an insulating support, +F, and carrying a concentric disk of ebonite, H. This latter receives a +hollow and closed hemisphere, J, of yellow metal, whose base has a +smaller diameter than that of the disk, H, and is perfectly insulated by +the latter. Another yellow-metal hemisphere, S, open below, is connected +with an insulating handle, G. The basal diameter of this second +hemisphere is such that when the latter is placed over J its edge rests +upon the lower disk, M. These various pieces being supposed placed as +shown in the figure, the shell, S, forms with the disk, M, a hollow, +closed hemisphere that imprisons the hemisphere, J, which is likewise +hollow and closed, and perfectly insulated from the former. + +[Illustration] + +The shell, S, is provided internally with a curved yellow-metal spring, +whose point of attachment is at B, and whose free extremity is connected +with an ebonite button, K, which projects from the shell, S. By pressing +this button, a contact may be established between the external +hemisphere (formed of the pieces, S and M), and the internal one, J. As +soon as the button is left to itself, the spring again begins to bear +against the interior surface of S, and the two hemispheres are again +insulated. + +The experiment is performed in this wise: The shell, S, is removed. Then +a disk of steatite affixed to an insulating handle is rubbed for a few +instants with a fox's "brush," and held near J until a spark occurs. +Then the apparatus is grasped by the support, F, and an elder-pith ball +suspended by a flaxen thread from a good conducting support is brought +near J. The ball will be quickly repelled, and care must be taken that +it does not come into contact with J. After this the apparatus is placed +upon a table, the shell, S, is taken by its handle, G, and placed in the +position shown in the figure, and a momentary contact is established +between the two hemispheres by pressing the button, K. Then the shell, +S, is lifted, and the disk, M, is touched at the same time with the +other hand. If, now, the pith ball be brought near S, it will be quickly +repelled, while it will remain stationary if it be brought near J, thus +proving that all the electricity passed from J to S at the moment of +contact.--_La Lumiere Electrique_. + + * * * * * + + + + +THE COLSON TELEPHONE. + + +This apparatus has recently been the object of some experiments which +resulted in its being finally adopted in the army. We think that our +readers will read a description of it with interest. Its mode of +construction is based upon a theoretic conception of the lines of force, +which its inventor explains as follows in his Elementary Treatise on +Electricity: + +"To every position of the disk of a magnetic telephone with respect to +the poles of the magnet there corresponds a certain distribution of the +lines of force, which latter shift themselves when the disk is +vibrating. If the bobbin be met by these lines in motion, there will +develop in its wire a difference of potential that, according to +Faraday's law, will be proportional to their number. All things equal, +then, a telephone transmitter will be so much the more potent in +proportion as the lines set in motion by the vibrations of the disk and +meeting the bobbin wire are greater in number. In like manner, a +receiver will be so much the more potent in proportion as the lines of +force, set in motion by variations in the induced currents that are +traversing the bobbin and meeting the disk, are more numerous. It will +consequently be seen that, generally speaking, it is well to send as +large a number of lines of force as possible through the bobbin." + +[Illustration: FIG. 1.--THE COLSON TELEPHONE.] + +In order to obtain such a result, the thin tin-plate disk has to be +placed between the two poles of the magnet. The pole that carries the +fine wire bobbin acts at one side and in the center of the disk, while +the other is expanded at the extremity and acts upon the edge and the +other side. This pole is separated from the disk by a copper washer, and +the disk is thus wholly immersed in the magnetic field, and is traversed +by the lines of force radiatingly. + +This telephone is being constructed by Mr. De Branville, with the +greatest care, in the form of a transmitter (Fig. 2) and receiver (Fig. +3). At A may be seen the magnet with its central pole, P, and its +eccentric one, P'. This latter traverses the vibrating disk, M, through +a rubber-lined aperture and connects with the soft iron ring, F, that +forms the polar expansion. These pieces are inclosed in a nickelized +copper box provided with a screw cap, C. The resistance of both the +receiver and transmitter bobbin is 200 ohms. + +[Illustration: FIG. 2.--TRANSMITTER TAKEN APART.] + +The transmitter is 31/2 in. in diameter, and is provided with a +re-enforcing mouthpiece. It is regulated by means of a screw which is +fixed in the bottom of the box, and which permits of varying the +distance between the disk and the core that forms the central pole of +the magnet. The regulation, when once effected, lasts indefinitely. The +regulation of the receiver, which is but 21/4 in. in diameter, is +performed once for all by the manufacturer. One of the advantages of +this telephone is that its regulation is permanent. Besides this, it +possesses remarkable power and clearness, and is accompanied with no +snuffling sounds, a fact doubtless owing to all the molecules of the +disk being immersed in the magnetic field, and to the actions of the two +poles occurring concentrically with the disk. As we have above said, +this apparatus is beginning to be appreciated, and has already been the +object of several applications in the army. The transmitter is used by +the artillery service in the organization of observatories from which to +watch firing, and the receiver is added to the apparatus pertaining to +military telegraphy. The two small receivers are held to the lens of the +operator by the latter's hat strap, while the transmitter is suspended +in a case supported by straps, with the mouthpieces near the face (Fig. +1). + +In the figure, the case is represented as open, so as to show the +transmitter. The empty compartment below is designed for the reception +and carriage of the receivers, straps, and flexible cords. This +arrangement permits of calling without the aid of special apparatus, and +it has also the advantage of giving entire freedom to the man on +observation, this being something that is indispensable in a large +number of cases. + +[Illustration: FIG. 3.--RECEIVER TAKEN APART.] + +In certain applications, of course, the receivers may be combined with a +microphone; yet on an aerial as well as on a subterranean line the +transmitter produces effects which, as regards intensity and clearness, +are comparable with those of a pile transmitter. + +Stations wholly magnetic may be established by adding to the transmitter +and two receivers a Sieur phonic call, which will actuate them +powerfully, and cause them to produce a noise loud enough for a call. It +would be interesting to try this telephone on a city line, and to a +great distance on those telegraph lines that are provided with the Van +Rysselberghe system. Excellent results would certainly be obtained, for, +as we have recently been enabled to ascertain, the voice has a +remarkable intensity in this telephone, while at the same time perfectly +preserving its quality.--_La Nature_. + + * * * * * + +[NATURE.] + + + + +THE MELDOMETER. + + +The apparatus which I propose to call by the above name +([mu][epsilon][lambda][delta][omega], to melt) consists of an adjunct to +the mineralogical microscope, whereby the melting-points of minerals may +be compared or approximately determined and their behavior watched at +high temperatures either alone or in the presence of reagents. + +As I now use it, it consists of a narrow ribbon of platinum (2 mm. wide) +arranged to traverse the field of the microscope. The ribbon, clamped in +two brass clamps so as to be readily renewable, passes bridgewise over a +little scooped-out hollow in a disk of ebony (4 cm. diam.). The clamps +also take wires from a battery (3 Groves cells); and an adjustable +resistance being placed in circuit, the strip can be thus raised in +temperature up to the melting-point of platinum. + +The disk being placed on the stage of the microscope the platinum strip +is brought into the field of a 1" objective, protected by a glass slip +from the radiant heat. The observer is sheltered from the intense light +at high temperatures by a wedge of tinted glass, which further can be +used in photometrically estimating the temperature by using it to obtain +extinction of the field. Once for all approximate estimations of the +temperature of the field might be made in terms of the resistance of the +platinum strip, the variation of such resistance with rise of +temperature being known. Such observations being made on a suitably +protected strip might be compared with the wedge readings, the latter +being then used for ready determinations. Want of time has hindered me +from making such observations up to this. + +The mineral to be experimented on is placed in small fragments near the +center of the platinum ribbon, and closely watched while the current is +increased, till the melting-point of the substance is apparent. Up to +the present I have only used it comparatively, laying fragments of +different fusibilities near the specimen. In this way I have melted +beryl, orthoclase, and quartz. I was much surprised to find the last +mineral melt below the melting-point of platinum. I have, however, by me +as I write, a fragment, formerly clear rock-crystal, so completely fused +that between crossed Nicols it behaves as if an amorphous body, save in +the very center where a speck of flashing color reveals the remains of +molecular symmetry. Bubbles have formed in the surrounding glass. + +Orthoclase becomes a clear glass filled with bubbles: at a lower +temperature beryl behaves in the same way. + +Topaz whitens to a milky glass--apparently decomposing, throwing out +filmy threads of clear glass and bubbles of glass which break, +liberating a gas (fluorine?) which, attacking the white-hot platinum, +causes rings of color to appear round the specimen. I have now been +using the apparatus for nearly a month, and in its earliest days it led +me right in the diagnosis of a microscopical mineral, iolite, not before +found in our Irish granite, I think. The unlooked-for characters of the +mineral, coupled with the extreme minuteness of the crystals, led me +previously astray, until my meldometer fixed its fusibility for me as +far above the suspected bodies. + +Carbon slips were at first used, as I was unaware of the capabilities of +platinum. + +A form of the apparatus adapted, at Prof. Fitzgerald's suggestion, to +fit into the lantern for projection on the screen has been made for me +by Yeates. In this form the heated conductor passes both below and above +the specimen, which is regarded from a horizontal direction. + +J. JOLY. + +Physical Laboratory, Trinity College, Dublin. + + * * * * * + +[AMERICAN ANNALS OF THE DEAF AND DUMB.] + + + + +TOUCH TRANSMISSION BY ELECTRICITY IN THE EDUCATION OF DEAF-MUTES. + + +Progress in electrical science is daily causing the world to open its +eyes in wonder and the scientist to enlarge his hopes for yet greater +achievements. The practical uses to which this subtile fluid, +electricity, is being put are causing changes to be made in time-tested +methods of doing things in domestic, scientific, and business circles, +and the time has passed when startling propositions to accomplish this +or that by the assistance of electricity are dismissed with incredulous +smiles. This being the case, no surprise need follow the announcement of +a device to facilitate the imparting of instruction to deaf children +which calls into requisition some service from electricity. + +The sense of touch is the direct medium contemplated, and it is intended +to convey, with accuracy and rapidity, messages from the operator (the +teacher) to the whole class simultaneously by electrical +transmission.[1] + +[Footnote 1: By the same means two deaf-mutes, miles apart, might +converse with each other, and the greatest difficulty in the way of a +deaf-mute becoming a telegraph operator, that of receiving messages, +would be removed. The latter possibilities are incidentally mentioned +merely as of scientific interest, and not because of their immediate +practical value. The first mentioned use to which the device may be +applied is the one considered by the writer as possibly of practical +value, the consideration of which suggested the appliance to him.] + +An alphabet is formed upon the palm of the left hand and the inner side +of the fingers, as shown by the accompanying cut, which, to those +becoming familiar with it, requires but a touch upon a certain point of +the hand to indicate a certain letter of the alphabet. + +A rapid succession of touches upon various points of the hand is all +that is necessary in spelling a sentence. The left hand is the one upon +which the imaginary alphabet is formed, merely to leave the right hand +free to operate without change of position when two persons only are +conversing face to face. + +The formation of the alphabet here figured is on the same principle as +one invented by George Dalgarno, a Scottish schoolmaster, in the year +1680, a cut of which maybe seen on page 19 of vol. ix. of the _Annals_, +accompanying the reprint of a work entitled "_Didascalocophus_." +Dalgarno's idea could only have been an alphabet to be used in +conversation between two persons _tete a tete_, and--except to a limited +extent in the Horace Mann School and in Professor Bell's teaching--has +not come into service in the instruction of deaf-mutes or as a means of +conversation. There seems to have been no special design or system in +the arrangement of the alphabet into groups of letters oftenest +appearing together, and in several instances the proximity would +seriously interfere with distinct spelling; for instance, the group "u," +"y," "g," is formed upon the extreme joint of the little finger. The +slight discoverable system that seems to attach to his arrangement of +the letters is the placing of the vowels in order upon the points of the +fingers successively, beginning with the thumb, intended, as we suppose, +to be of mnemonic assistance to the learner. Such assistance is hardly +necessary, as a pupil will learn one arrangement about as rapidly as +another. If any arrangement has advantage over another, we consider it +the one which has so grouped the letters as to admit of an increased +rapidity of manipulation. The arrangement of the above alphabet, it is +believed, does admit of this. Yet it is not claimed that it is as +perfect as the test of actual use may yet make it. Improvements in the +arrangement will, doubtless, suggest themselves, when the alterations +can be made with little need of affecting the principle. + +In order to transmit a message by this alphabet, the following described +appliance is suggested: A matrix of cast iron, or made of any suitable +material, into which the person receiving the message (the pupil) places +his left hand, palm down, is fixed to the table or desk. The matrix, +fitting the hand, has twenty-six holes in it, corresponding in position +to the points upon the hand assigned to the different letters of the +alphabet. In these holes are small styles, or sharp points, which are so +placed as but slightly to touch the hand. Connected with each style is a +short line of wire, the other end of which is connected with a principal +wire leading to the desk of the operator (the teacher), and there so +arranged as to admit of opening and closing the circuit of an electric +current at will by the simple touch of a button, and thereby producing +along the line of that particular wire simultaneous electric impulses, +intended to act mechanically upon all the styles connected with it. By +these impulses, produced by the will of the sender, the styles are +driven upward with a quick motion, but with only sufficient force to be +felt and located upon the hand by the recipient. Twenty-six of these +principal or primary wires are run from the teacher's desk (there +connected with as many buttons) under the floor along the line of +pupils' desks. From each matrix upon the desk run twenty-six secondary +wires down to and severally connecting with the twenty-six primary wires +under the floor. The whole system of wires is incased so as to be out of +sight and possibility of contact with foreign substances. The keys or +buttons upon the desk of the teacher are systematically arranged, +somewhat after the order of those of the type writer, which allows the +use of either one or both hands of the operator, and of the greatest +attainable speed in manipulation. The buttons are labeled "a," "b," "c," +etc., to "z," and an electric current over the primary wire running from +a certain button (say the one labeled "a") affects only those secondary +wires connected with the styles that, when excited, produce upon the +particular spot of the hands of the receivers the tactile impression to +be interpreted as "a." And so, whenever the sender touches any of the +buttons on his desk, immediately each member of the class feels upon the +palm of his hand the impression meant to be conveyed. The contrivance +will admit of being operated with as great rapidity as it is probable +human dexterity could achieve, i.e., as the strokes of an electric bell. +It was first thought of conveying the impressions directly by slight +electric shocks, without the intervention of further mechanical +apparatus, but owing to a doubt as to the physical effect that might be +produced upon the persons receiving, and as to whether the nerves might +not in time become partly paralyzed or so inured to the effect as to +require a stronger and stronger current, that idea was abandoned, and +the one described adopted. A diagram of the apparatus was submitted to a +skillful electrical engineer and machinist of Hartford, who gave as his +opinion that the scheme was entirely feasible, and that a simple and +comparatively inexpensive mechanism would produce the desired result. + +[Illustration: TOUCH TRANSMISSION BY ELECTRICITY.] + +The matter now to consider, and the one of greater interest to the +teacher of deaf children, is, Of what utility can the device be in the +instruction of deaf-mutes? What advantage is there, not found in the +prevailing methods of communication with the deaf, i.e., by gestures, +dactylology, speech and speech-reading, and writing? + +I. The language of gestures, first systematized and applied to the +conveying of ideas to the deaf by the Abbe de l'Epee during the latter +part of the last century, has been, in America, so developed and +improved upon by Gallaudet, Peet, and their successors, as to leave but +little else to be desired for the purpose for which it was intended. The +rapidity and ease with which ideas can be expressed and understood by +this "language" will never cease to be interesting and wonderful, and +its value to the deaf can never fail of being appreciated by those +familiar with it. But the genius of the language of signs is such as to +be in itself of very little, if any, direct assistance in the +acquisition of syntactical language, owing to the diversity in the order +of construction existing between the English language and the language +of signs. Sundry attempts have been made to enforce upon the +sign-language conformity to the English order, but they have, in all +cases known to the writer, been attended with failure. The sign-language +is as immovable as the English order, and in this instance certainly +Mahomet and the mountain will never know what it is to be in each +other's embrace. School exercises in language composition are given with +great success upon the basis of the sign-language. But in all such +exercises there must be a translation from one language to the other. +The desideratum still exists of an increased percentage of pupils +leaving our schools for the deaf, possessing a facility of expression in +English vernacular. This want has been long felt, and endeavoring to +find a reason for the confessedly low percentage, the sign-language has +been too often unjustly accused. It is only when the sign-language is +abused that its merit as a means of instruction degenerates. The most +ardent admirers of a proper use of signs are free to admit that any +excessive use by the pupils, which takes away all opportunities to +express themselves in English, is detrimental to rapid progress in +English expression. + +II. To the general public, dactylology or finger spelling is the +sign-language, or the basis of that language, but to the profession +there is no relation between the two methods of communication. +Dactylology has the advantage of putting language before the eye in +conformity with English syntax, and it has always held its place as one +of the elements of the American or eclectic method. This advantage, +however, is not of so great importance as to outweigh the disadvantages +when, as has honestly been attempted, it asserts its independence of +other methods. Very few persons indeed, even after long practice, become +sufficiently skillful in spelling on the fingers to approximate the +rapidity of speech. But were it possible for all to become rapid +spellers, another very important requisite is necessary before the +system could be a perfect one, that is, the ability to _read_ rapid +spelling. The number of persons capable of reading the fingers beyond a +moderate degree of rapidity is still less than the number able to spell +rapidly. While it is physically possible to follow rapid spelling for +twenty or thirty minutes, it can scarcely be followed longer than that. +So long as this is true, dactylology can hardly claim to be more than +one of the _elements_ of a system of instruction for the deaf. + +III. Articulate speech is another of the elements of the eclectic +method, employed with success inversely commensurate with the degree of +deficiency arising from deafness. Where the English order is already +fixed in his mind, and he has at an early period of life habitually used +it, there is comparatively little difficulty in instructing the deaf +child by speech, especially if he have a quick eye and bright intellect. +But the number so favored is a small percentage of the great body of +deaf-mutes whom we are called upon to educate. When it is used as a +_sole_ means of educating the deaf as a class its inability to stand +alone is as painfully evident as that of any of the other component +parts of the system. It would seem even less practicable than a sole +reliance upon dactylology would be, for there can be no doubt as to what +a word is if spelled slowly enough, and if its meaning has been learned. +This cannot be said of speech. Between many words there is not, when +uttered, the slightest visible distinction. Between a greater number of +others the distinction is so slight as to cause an exceedingly nervous +hesitation before a guess can be given. Too great an imposition is put +upon the eye to expect it to follow unaided the extremely circumscribed +gestures of the organs of speech visible in ordinary speaking. The ear +is perfection as an interpreter of speech to the brain. It cannot +correctly be said that it is _more_ than perfection. It is known that +the ear, in the interpretation of vocal sounds, is capable of +distinguishing as many as thirty-five sounds per second (and oftentimes +more), and to follow a speaker speaking at the rate of more than two +hundred words per minute. If this be perfection, can we expect the _eye_ +of ordinary mortal to reach it? Is there wonder that the task is a +discouraging one for the deaf child? + +But it has been asserted that while a large percentage (practically all) +of the deaf _can_, by a great amount of painstaking and practice, become +speech readers in some small degree, a relative degree of facility in +articulation is not nearly so attainable. As to the accuracy of this +view, the writer cannot venture an opinion. Judging from the average +congenital deaf-mute who has had special instruction in speech, it can +safely be asserted that their speech is laborious, and far, very far, +from being accurate enough for practical use beyond a limited number of +common expressions. This being the case, it is not surprising that as an +unaided means of instruction it cannot be a success, for English neither +understood when spoken, nor spoken by the pupil, cannot but remain a +foreign language, requiring to pass through some other form of +translation before it becomes intelligible. + +There are the same obstacles in the use of the written or printed word +as have been mentioned in connection with dactylology, namely, lack of +rapidity in conveying impressions through the medium of the English +sentence. + +I have thus hastily reviewed the several means which teachers generally +are employing to impart the use of English to deaf pupils, for the +purpose of showing a common difficulty. The many virtues of each have +been left unnoticed, as of no pertinence to this article. + +The device suggested at the beginning of this paper, claiming to be +nothing more than a school room appliance intended to supplement the +existing means for giving a knowledge and practice of English to the +deaf, employs as its interpreter a different sense from the one +universally used. The sense of sight is the sole dependence of the deaf +child. Signs, dactylology, speech reading, and the written and printed +word are all dependent upon the eye for their value as educational +instruments. It is evident that of the two senses, sight and touch, if +but one could be employed, the choice of sight as the one best adapted +for the greatest number of purposes is an intelligent one; but, as the +choice is not limited, the question arises whether, in recognizing the +superior adaptability to our purpose of the one, we do not lose sight of +a possibly important, though secondary, function in the other. If sight +were all-sufficient, there would be no need of a combination. But it +cannot be maintained that such is the case. The plan by which we acquire +our vernacular is of divine, and not of human, origin, and the senses +designed for special purposes are not interchangeable without loss. The +theory that the loss of a certain sense is nearly, if not quite, +compensated for by increased acuteness of the remaining ones has been +exploded. Such a theory accuses, in substance, the Maker of creating +something needless, and is repugnant to the conceptions we have of the +Supreme Being. When one sense is absent, the remaining senses, in order +to equalize the loss, have imposed upon them an unusual amount of +activity, from which arises skill and dexterity, and by which the loss +of the other sense is in some measure alleviated, but not supplied. No +_additional_ power is given to the eye after the loss of the sense of +hearing other than it might have acquired with the same amount of +practice while both faculties were active. The fact, however, that the +senses, in performing their proper functions, are not overtaxed, and are +therefore, in cases of emergency, capable of being extended so as to +perform, in various degrees, additional service, is one of the wise +providences of God, and to this fact is due the possibility of whatever +of success is attained in the work of educating the deaf, as well as the +blind. + +In the case of the blind, the sense of touch is called into increased +activity by the absence of the lost sense; while in the case of the +deaf, sight is asked to do this additional service. A blind person's +education is received principally through the _two_ senses of hearing +and touch. Neither of these faculties is so sensible to fatigue by +excessive use as is the sense of sight, and yet the eye has, in every +system of instruction applied to the deaf, been the sole medium. In no +case known to the writer, excepting in the celebrated case of Laura +Bridgman and a few others laboring under the double affliction of +deafness and blindness, has the sense of touch been employed as a means +of instruction.[1] + +[Footnote 1: This article was written before Professor Bell had made his +interesting experiments with his "parents' class" of a touch alphabet, +to be used upon the pupil's shoulder in connection with the oral +teaching.--E.A.F.] + +Not taking into account the large percentage of myopes among the deaf, +we believe there are other cogent reasons why, if found practicable, the +use of the sense of touch may become an important element in our +eclectic system of teaching. We should reckon it of considerable +importance if it were ascertained that a portion of the same work now +performed by the eye could be accomplished equally as well through +feeling, thereby relieving the eye of some of its onerous duties. + +We see no good reason why such accomplishment may not be wrought. If, +perchance, it were discovered that a certain portion could be performed +in a more efficient manner, its value would thus be further enhanced. + +In theory and practice, the teacher of language to the deaf, by whatever +method, endeavors to present to the eye of the child as many completed +sentences as are nominally addressed to the ear--having them "caught" by +the eye and reproduced with as frequent recurrence as is ordinarily done +by the child of normal faculties. + +In our hasty review of the methods now in use we noted the inability to +approximate this desirable process as a common difficulty. The facility +now ordinarily attained in the manipulation of the type writer, and the +speed said to have been reached by Professor Bell and a private pupil of +his by the Dalgarno touch alphabet, when we consider the possibility of +a less complex mechanism in the one case and a more systematic grouping +of the alphabet in the other, would lead us to expect a more rapid means +of communication than is ordinarily acquired by dactylology, speech (by +the deaf), or writing. Then the ability to receive the communication +rapidly by the sense of feeling will be far greater. No part of the body +except the point of the tongue is as sensible to touch as the tips of +the fingers and the palm of the hand. Tactile discrimination is so acute +as to be able to interpret to the brain significant impressions produced +in very rapid succession. Added to this advantage is the greater one of +the absence of any more serious attendant physical or nervous strain +than is present when the utterances of speech fall upon the tympanum of +the ear. To sum up, then, the advantages of the device we find-- + +First. A more rapid means of communication with the deaf by syntactic +language, admitting of a greater amount of practice similar to that +received through the ear by normal children. + +Second. Ability to receive this rapid communication for a longer +duration and without ocular strain. + +Third. Perfect freedom of the eye to watch the expression on the +countenance of the sender. + +Fourth. In articulation and speech-reading instruction, the power to +assist a class without distracting the attention of the eye from the +vocal organs of the teacher. + +Fifth. Freedom of the right hand of the pupil to make instantaneous +reproduction in writing of the matter being received through the sense +of feeling, thereby opening the way for a valuable class exercise. + +Sixth. The possible mental stimulus that accompanies the mastery of a +new language, and the consequent ability to receive known ideas through +a new medium. + +Seventh. A fresh variety of class exercises made possible. + +The writer firmly believes in the good that exists in all methods that +are, or are to be; in the interdependence rather than the independence +of all methods; and in all school-room appliances tending to supplement +or expedite the labors of the teacher, whether they are made of +materials delved from the earth or snatched from the clouds. + +S. TEFFT WALKER, + +_Superintendent of the Kansas Institution, Olathe, Kans_. + + * * * * * + + + + +WATER GAS. + +THE RELATIVE VALUE OF WATER GAS AND OTHER GASES AS IRON REDUCING AGENTS. + +By B.H. THWAITE. + + +In order to approximately ascertain the relative reducing action of +water gas, carbon monoxide, and superheated steam on iron ore, the +author decided to have carried out the following experiments, which were +conducted by Mr. Carl J. Sandahl, of Stockholm, who also carried out the +analyses. The ore used was from Bilbao, and known as the Ruby Mine, and +was a good average hematite. The carbonaceous material was the Trimsaran +South Wales anthracite, and contained about 90 per cent. of carbon. + +A small experimental furnace was constructed of the form shown by +illustration, about 4 ft. 6 in. high and 2 ft. 3 in. wide at the base, +and gradually swelling to 2 ft. 9 in. at the top, built entirely of +fireclay bricks. Two refractory tubes, 2 in. square internally, and the +height of the furnace, were used for the double purpose of producing the +gas and reducing the ore. + +The end of the lower tube rested on a fireclay ladle nozzle, and was +properly jointed with fireclay; through this nozzle the steam or air was +supplied to the inside of the refractory tubes. In each experiment the +ore and fuel were raised to the temperature "of from 1,800 to 2,200 deg. +Fahr." by means of an external fire of anthracite. Great care was taken +to prevent the contact of the solid carbonaceous fuel with the ore. In +each experiment in which steam was used, the latter was supplied at a +temperature equivalent to 35 lb. to the square inch. + +The air for producing the carbon monoxide (CO) gas was used at the +temperature of the atmosphere. As near as possible, the same conditions +were obtained in each experiment, and the equivalent weight of air was +sent through the carbon to generate the same weight of CO as that +generated when steam was used for the production of water gas. + +[Illustration] + +_First Experiment, Steam (per se)_.--Both tubes, A and B, were filled +with ore broken to the size of nuts. The tube, A, was heated to about +2,000 deg. Fahr., the upper one to about 1,500 deg. + +NOTE.--In this experiment, part of the steam was dissociated in passing +through the turned-up end of the steam supply pipe, which became very +hot, and the steam would form with the iron the magnetic oxide +(Fe_{3}O_{4}). The reduction would doubtless be due to this +dissociation. The pieces of ore found on lowest end of the tube, A, were +dark colored and semi-fused; part of one of these pieces was crushed +fine, and tested; see column I. The remainder of these black pieces was +mixed with the rest of the ore contained in tube, A, and ground and +tested; see column II. The ore in upper tube was all broken up together +and tested; see column III. When finely crushed, the color of No. I. was +bluish black; No. II., a shade darker red; No. III., a little darker +than the natural color of the ore. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 68.55 | 76.47 | 84.81 +Ferrous oxide (FeO). | 16.20 | 9.50 | 1.50 + +---------+---------+--------- + Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | 32.55 | 55.36 | 81.47 +Magnetic oxide (Fe_{3}O_{4}).| 52.20 | 30.61 | 4.84 +Ferrous oxide (FeO). | | | + +---------+---------+--------- +Total. | 84.75 | 85.97 | 86.31 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 6.93 | 4.02 | 1.07 +Metallic iron. | 60.59 | 60.92 | 60.54 +-----------------------------+---------+---------+--------- + +_Second Experiment, Water Gas_.--The tube, A, was filled with small +pieces of anthracite, and heated until all the volatile matter had been +expelled. The tube, B, was then placed in tube, A, the joint being made +with fireclay, and to prevent the steam from carrying small particles of +solid carbon into ore in the upper tube, the anthracite was divided from +the ore by means of a piece of fine wire gauze. The steam at a pressure +of about 35 lb. to the square inch was passed through the anthracite. +The tube, A, was heated to white heat, the tube, B, at its lower end to +bright red, the top to cherry red. + +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Experiment. | 1st. | 2d. | 3d. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Number. | I. | II. | III.| I. | II. | III.| IV. | I. | II. | III.| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Total Iron. |60.59|60.92|60.54|65.24|61.71|61.93|57.23|59.73|57.93|55.54| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Iron occurring as +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |12.60| 7.39| 1.17|46.98|18.59| 4.03| 0.84|29.45| 2.69| 1.12 + Fe_{2}O_{3} |47.99|53.33|59.37|18.26|43.12|57.90|56.39|30.28|55.24|54.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of Oxides. | +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + FeO. |16.20| 9.50| 1.50|60.40|23.90| 5.18| 1.08|37.86| 3.46| 1.44 + Fe_{2}O_{3}. |68.55|76.47|84.81|26.08|61.60|82.71|80.55|43.26|78.91|77.74 + Total. |84.75|85.97|86.31|86.48|85.50|87.89|81.63|81.12|82.37|79.18 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Oxygen in Ore. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +Before experiment.|25.97|26.10|26.05|27.96|26.45|26.54|24.52|25.60|24.81|23.80 +After experiment. |24.16|25.05|25.77|21.24|23.79|25.96|24.40|21.39|24.44|23.64 + Difference. | 1.81| 1.05| 0.28| 6.72| 2.66| 0.58| 0.12| 4.21| 0.37| 0.16 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Per cent. of oxygen reduced. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + oxygen reduced. | 6.93| 4.02| 1.07|24.03|10.02| 2.18| 0.49|16.44| 1.49| 0.42 +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +Degree of Oxidation of the Ore after the Experiment. +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +FeO. | ... | ... | ... |84.66| ... | ... | ... |18.40| ... | ... | +Fe_{3}O_{4}. |52.20|30.61| 4.84|37.82|77.01|28.12| 3.88|62.72|11.14| 4.64| +Fe_{2}O_{3}. |32.55|55.36|81.47| ... | 8.49|59.77|77.75| ... |71.23|74.54| +Total. |84.75|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97|85.97| +------------------+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ + +------------------+-----------------+-----------------------+-----------------+ +The ore having | | | | +been exposed to | Steam. | Water gas. | Carbon monoxide.| +------------------+-----------------+-----------------------+-----------------+ + +_Four Samples were Tested_.--I. The bottom layer, 11/4 in. thick; the +color of ore quite black, with small particles of reduced spongy +metallic iron. II. Layer above I., 41/4 in. thick; the color was also +black, but showed a little purple tint. III. Layer above II., 5 in. +thick; purple red color. IV. Layer above III., ore a red color. The +analyses gave: + +-----------------------------+---------+---------+---------+--------- + | I. | II. | III. | IV. + +---------+---------+---------+--------- + |per cent.|per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 26.08 | 61.60 | 82.71 | 80.55 +Ferrous oxide (FeO). | 60.40 | 23.90 | 5.18 | 1.08 + +---------+---------+---------+--------- + Total. | 86.48 | 85.50 | 87.89 | 81.63 + +---------+---------+---------+--------- +Calculated: | | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 8.49 | 59.77 | 77.75 +Magnetic oxide (Fe_{3}O_{4}).| 37.82 | 77.01 | 28.12 | 3.88 +Ferrous oxide (FeO). | 48.66 | | | + +---------+---------+---------+--------- +Total. | 86.48 | 85.41 | 87.89 | 81.63 + +---------+---------+---------+--------- +Percentage of total + oxygen reduced. | 24.03 | 10.02 | 2.26 | 0.49 +Metallic iron. | 65.24 | 61.71 | 61.93 | 57.23 +-----------------------------+---------+---------+---------+--------- + +NOTE.--All the carbon dioxide (CO_{2}) occurring in the ore as calcic +carbonate was expelled. + +_Third Experiment, Carbon monoxide_ (CO).--The tube A was filled with +anthracite in the manner described for the second experiment, and heated +to drive off the volatile matter, before the ore was placed in the upper +tube, B, and the anthracite was divided from the ore by means of a piece +of fine wire gauze. The lower tube, A, was heated to the temperature of +white heat, the upper one, B, to a temperature of bright red. I. Layer, +1 in. thick from the bottom; ore dark brownish colored. II. Layer 4 in. +thick above I.; ore reddish brown. III. Layer 11 in. thick above II.; +ore red color. The analyses gave: + +-----------------------------+---------+---------+--------- + | I. | II. | III. + +---------+---------+--------- + |per cent.|per cent.|per cent. +Ferric oxide (Fe_{2}O_{3}). | 43.26 | 78.91 | 77.74 +Ferrous oxide (FeO). | 37.86 | 3.46 | 1.44 + +---------+---------+--------- + Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Calculated: | | | +Ferric oxide (Fe_{2}O_{3}). | ... | 71.23 | 74.54 +Magnetic oxide (Fe_{3}O_{4}).| 62.72 | 11.14 | 4.64 +Ferrous oxide (FeO). | 18.40 | | + +---------+---------+--------- +Total. | 81.12 | 82.37 | 79.18 + +---------+---------+--------- +Percentage of total + oxygen reduced. | 16.44 | 1.49 | 0.42 +Metallic iron. | 59.73 | 57.93 | 55.54 +-----------------------------+---------+---------+--------- + +NOTE.--The carbon monoxide (CO) had failed to remove from the ore the +carbon dioxide existing as calcic carbonate. The summary of experiments +in the following table appears to show that the water gas is a more +powerful reducing agent than CO in proportion to the ratio of as + + 4.21 x 100 +4.21 : 6.72, or ------------ = 52 per cent. + 72 + +Mr. B.D. Healey, Assoc. M. Inst. C.E., and the author are just now +constructing large experimental plant in which water gas will be used as +the reducing agent. This plant would have been at work before this but +for some defects in the valvular arrangements, which will be entirely +removed in the new modifications of the plant. + + * * * * * + + + + +ANTISEPTIC MOUTH WASH. + + +Where an antiseptic mouth wash is needed, Mr. Sewill prescribes the use +of perchloride of mercury in the following form: One grain of the +perchloride and 1 grain of chloride of ammonium to be dissolved in 1 oz. +of eau de Cologne or tincture of lemons, and a teaspoonful of the +solution to be mixed with two-thirds of a wineglassful of water, making +a proportion of about 1 of perchloride in 5,000 parts.--_Chemist and +Druggist_. + + * * * * * + + + + +ANNATTO. + +[Footnote: Read at an evening meeting of the North British Branch of the +Pharmaceutical Society, January 21.] + +By WILLIAM LAWSON. + + +The subject which I have the honor to bring shortly before your notice +this evening is one that formed the basis of some instructive remarks by +Dr. Redwood in November, 1855, and also of a paper by Dr. Hassall, read +before the Society in London in January, 1856, which latter gave rise to +an animated discussion. The work detailed below was well in hand when +Mr. MacEwan drew my attention to these and kindly supplied me with the +volume containing reports of them. Unfortunately, they deal principally +with the adulterations, while I was more particularly desirous to learn +the composition in a general way, and especially the percentage of +coloring resin, the important constituent in commercial annatto. Within +the last few years it was one of the articles in considerable demand in +this part of the country; now it is seldom inquired for. This, +certainly, is not because butter coloring has ceased to be employed, and +hence the reason for regretting that the percentage of resin was not +dealt with in the articles referred to, so that a comparison could have +been made between the commercial annatto of that period and that which +exists now. In case some may not be in possession of literature bearing +on it--which, by the way, is very meager--it may not be out of place to +quote some short details as to its source, the processes for obtaining +it, the composition of the raw material, and then the method followed in +the present inquiry will be given, together with the results of the +examination of ten samples; and though the subject doubtless has more +interest for the country than for the town druggist, still, I trust it +will have points of interest for both. + +Annatto is the coloring matter derived from the seeds of an evergreen +plant, _Bixa Orellana_, which grows in the East and West Indian Islands +and South America, in the latter of which it is principally prepared. +Two kinds are imported, Spanish annatto, made in Brazil, and flag or +French, made mostly in Cayenne. These differ considerably in characters +and properties, the latter having a disagreeable putrescent odor, while +the Spanish is rather agreeable when fresh and good. It is, however, +inferior to the flag as a coloring or dyeing agent. The seeds from which +the substance is obtained are red on the outside, and two methods are +followed in order to obtain it. One is to rub or wash off the coloring +matter with water, allow it to subside, and to expose it to spontaneous +evaporation till it acquires a pasty consistence. The other is to bruise +the seeds, mix them with water, and allow fermentation to set in, during +which the coloring matter collects at the bottom, from which it is +subsequently removed and brought to the proper consistence by +spontaneous evaporation. These particulars, culled from Dr. Redwood's +remarks, may suffice to show its source and the methods for obtaining +it. + +Dr. John gives the following as the composition of the pulp surrounding +the seeds: Coloring resinous matter, 28; vegetable gluten, 26.5; +ligneous fiber, 20; coloring, 20; extractive matter, 4; and a trace of +spicy and acid matter. + +It must be understood, however, that commercial annatto, having +undergone processes necessary to fit it for its various uses, as well as +to preserve it, differs considerably from this; and though it may not be +true, as some hint, that manufacturing in this industry is simply a term +synonymous with adulterating, yet results will afterward be given +tending to show that there are articles in the market which have little +real claim to the title. I tried, but failed, to procure a sample of raw +material on which to work, with a view to learn something of its +characters and properties in this state, and thus be able to contrast it +with the manufactured or commercial article. The best thing to do in the +circumstances, I thought, was to operate on the highest priced sample at +disposal, and this was done in all the different ways that suggested +themselves. The extraction of the resin by means of alcohol--the usual +way, I believe--was a more troublesome operation than it appeared to be, +as the following experiment will show: One hundred grains of No. 8 were +taken, dried thoroughly, reduced to fine powder, and introduced into a +flask containing 4 ounces of alcohol in the form of methylated spirit, +boiled for an hour--the flask during the operation being attached to an +inverted condenser--filtered off, and the residue treated with a smaller +amount of the spirit and boiled for ten minutes. This was repeated with +diminishing quantities until in all 14 ounces had been used before the +alcoholic solution ceased to turn blue on the addition to it of strong +sulphuric acid, or failed to give a brownish precipitate with stannous +chloride. As the sample contained a considerable quantity of potassium +carbonate, in which the resin is soluble, it was thought that by +neutralizing this it might render the resin more easy of extraction. +This was found to be so, but it was accompanied by such a mass of +extractive as made it in the long run more troublesome, and hence it was +abandoned. Thinking the spirit employed might be too weak, an experiment +with commercial absolute alcohol was carried out as follows: One hundred +grains of a red sample, No. 4, were thoroughly dried, powdered finely, +and boiled in 2 ounces of the alcohol, filtered, and the residue treated +with half an ounce more. This required to be repeated with fresh half +ounces of the alcohol until in all 71/2 were used; the time occupied from +first to last being almost three hours. This was considered +unsatisfactory, besides being very expensive, and so it, also, was set +aside, and a series of experiments with methylated spirit alone was set +in hand. The results showed that the easiest and most satisfactory way +was to take 100 grains (this amount being preferred, as it reduces error +to the minimum), dry thoroughly, powder finely, and macerate with +frequent agitation for twenty-four hours in a few ounces of spirit, then +to boil in this spirit for a short time, filter, and repeat the boiling +with a fresh ounce or so; this, as a rule, sufficing to completely +exhaust it of its resin. Wynter Blyth says that the red resin, or bixin, +is soluble in 25 parts of hot alcohol. It appears from these experiments +that much more is required to dissolve it out of commercial annatto. + +The full process followed consisted in determining the moisture by +drying 100 grains at 212 deg. F. till constant, and taking this dried +portion for estimation of the resin in the way just stated. The +alcoholic extract was evaporated to dryness over a water-bath, the +residue dissolved in solution of sodium carbonate, and the resin +precipitated by dilute sulphuric acid (these reagents being chosen as +the best after numerous trials with others), added in the slightest +possible excess. The resin was collected on a tared double filter paper, +washed with distilled water until the washings were entirely colorless, +dried and weighed. + +The ash was found in the usual way, and the extractive by the +difference. In the ash the amount soluble was determined, and +qualitatively examined, as was the insoluble portion in most of them. + +The results are as follows: + + | 1. | 2. | 3. | 4. | 5. | 6. | 7. | 8. | 9. | 10. +Moisture | 21.75| 21.60| 20.39| 69.73| 18.00| 18.28| 15.71| 38.18| 19.33| 22.50 +Resin | 3.00| 2.90| 1.00| 8.80| 3.00| 1.80| 5.40| 12.00| 5.90| 9.20 +Extrac- +tive | 57.29| 59.33| 65.00| 19.47| 58.40| 65.67| 26.89| 20.82| 23.77| 28.50 +Ash | 17.96| 16.17| 13.61| 2.00| 20.60| 14.25| 52.00| 29.00| 51.00| 39.80 +------------------------------------------------------------------------------- + |100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00|100.00 +------------------------------------------------------------------------------- +Ashes: | | | |Almost| | | | | | +Soluble | 13.20| 12.57| 7.50|wholly| 10.0| 11.75| 18.5 | 20.0 | 15.0 | 13.8 +Insoluble| 4.76| 3.60| 6.11| NaCl.| 10.6| 2.50| 33.5 | 9.0 | 36.0 | 26.0 + +The first six are the ordinary red rolls, with the exception of No. 4, +which is a red mass, the only one of this class direct from the +manufacturers. The remainder are brown cakes, all except No. 7 being +from the manufacturers direct. The ash of the first two was largely +common salt; that of No. 3 contained, besides this, iron in some +quantity. No. 4 is unique in many respects. It was of a bright red +color, and possessed a not disagreeable odor. It contained the largest +percentage of moisture and the lowest of ash; had, comparatively, a +large amount of coloring matter; was one of the cheapest, and in the +course of some dairy trials, carried out by an intelligent farmer, was +pronounced to be the best suited for coloring butter. So far as my +experience goes, it was a sample of the best commercial excellence, +though I fear the mass of water present and the absence of preserving +substances will assist in its speedy decay. Were such an article easily +procured in the usual way of business, there would not be much to +complain of, but it must not be forgotten that it was got direct from +the manufacturers--a somewhat suggestive fact when the composition of +some other samples is taken into account. No. 5 emitted a disagreeable +odor during ignition. The soluble portion of the ash was mostly common +salt, and the insoluble contained three of sand--the highest amount +found, although most of the reds contained some. No. 6 was a +vile-looking thing, and when associated in one's mind with butter gave +rise to disagreeable reflections. It was wrapped in a paper saturated +with a strongly smelling linseed oil. When it was boiled in water and +broken up, hairs, among other things, were observed floating about. It +contained some iron. The first cake, No. 7, gave off during ignition an +agreeable odor resembling some of the finer tobaccos, and this is +characteristic more or less of all the cakes. The ash weighed 52 per +cent., the soluble part of which, 18.5, was mostly potassium carbonate, +with some chlorides and sulphates; the insoluble, mostly chalk with iron +and alumina. No. 8--highest priced of all--had in the mass an odor which +I can compare to nothing else than a well rotted farmyard manure. Twenty +parts of the ash were soluble and largely potassium carbonate, the +insoluble being iron for the most part. The mineral portions of Nos. 9 +and 10 closely resemble No. 7. + +On looking over the results, it is found that the red rolls contained +starchy matters in abundance (in No. 4 the starch was to a large extent +replaced by water), and an ash, mostly sodium chloride, introduced no +doubt to assist in its preservation as well as to increase the color of +the resin--a well known action of salt on vegetable reds. The cakes, +which are mostly used for cheese coloring, I believe, all appeared to +contain turmeric, for they gave a more or less distinct reaction with +the boric acid test, and all except No. 8 contained large quantities of +chalk. These results in reference to extractive, etc., reveal nothing +that has not been known before. Wynter Blyth, who gives the only +analyses of annatto I have been able to find, states that the +composition of a fair commercial sample (which I take to mean the raw +article) examined by him was as follows: water, 24.2; resin, 28.8; ash, +22.5; and extractive, 24.5; and that of an adulterated (which I take to +mean a manufactured) article, water, 13.4; resin, 11.0; ash (iron, +silica, chalk, alumina, and common salt), 48.3; and extractive. 27.3. If +this be correct, it appears that the articles at present in the market, +or at least those which have come in my way, have been wretched +imitations of the genuine thing, and should, instead of being called +adulterated annatto, be called something else adulterated, but not +seriously, with annatto. I have it on the authority of the farmer +previously referred to, that 1/4 of an ounce of No. 4 is amply sufficient +to impart the desired cowslip tint to no less than 60 lb. of butter. +When so little is actually required, it does not seem of very serious +importance whether the adulterant or preservative be flour, chalk, or +water, but it is exasperating in a very high degree to have such +compounds as Nos. 3 and 6 palmed off as decent things when even Nos. 1, +2, and 5 have been rejected by dairymen as useless for the purpose. In +conclusion, I may be permitted to express the hope that others may be +induced to examine the annatto taken into stock more closely than I was +taught to do, and had been in the habit of doing, namely, to see if it +had a good consistence and an odor resembling black sugar, for if so, +the quality was above suspicion. + + * * * * * + + + + +JAPANESE RICE WINE AND SOJA SAUCE. + + +Professor P. Cohn has recently described the mode in which he has +manufactured the Japanese sake or rice wine in the laboratory. The +material used was "Tane Kosi," i.e., grains of rice coated with the +mycelium, conidiophores, and greenish yellow chains of conidia of +_Aspergillus Oryzoe_. The fermentation is caused by the mycelium of this +fungus before the development of the fructification. The rice is first +exposed to moist air so as to change the starch into paste, and then +mixed with grains of the "Tane Kosi." The whole mass of rice becomes in +a short time permeated by the soft white shining mycelium, which imparts +to it the odor of apple or pine-apple. To prevent the production of the +fructification, freshly moistened rice is constantly added for two or +three days, and then subjected to alcoholic fermentation from the +_Saccharomyces_, which is always present in the rice, but which has +nothing to do with the _Aspergillus_. The fermentation is completed in +two or three weeks, and the golden yellow, sherry-like sake is poured +off. The sample manufactured contained 13.9 per cent. of alcohol. +Chemical investigation showed that the _Aspergillus_ mycelium transforms +the starch into glucose, and thus plays the part of a diastase. + +Another substance produced from the _Aspergillus_ rice is the soja +sauce. The soja leaves, which contain little starch, but a great deal of +oil and casein, are boiled, mixed with roasted barley, and then with the +greenish yellow conidia powder of the _Aspergillus_. After the mycelium +has fructified, the mass is treated with a solution of sodium chloride, +which kills the _Aspergillus_, another fungus, of the nature of a +_Chalaza_, and similar to that produced in the fermentation of +"sauerkraut," appearing in its place. The dark-brown soja sauce then +separates. + + * * * * * + + + + +ALUMINUM. + +[Footnote: Annual address delivered by President J.A. Price before the +meeting of the Scranton Board of Trade, Monday, January 18, 1886.] + +By J.A. PRICE. + + +Iron is the basis of our civilization. Its supremacy and power it is +impossible to overestimate; it enters every avenue of development, and +it may be set down as the prime factor in the world's progress. Its +utility and its universality are hand in hand, whether in the +magnificent iron steamship of the ocean, the network of iron rail upon +land, the electric gossamer of the air, or in the most insignificant +articles of building, of clothing, and of convenience. Without it, we +should have miserably failed to reach our present exalted station, and +the earth would scarcely maintain its present population; it is indeed +the substance of substances. It is the Archimedean lever by which the +great human world has been raised. Should it for a moment forget its +cunning and lose its power, earthquake shocks or the wreck of matter +could not be more disastrous. However axiomatic may be everything that +can be said of this wonderful metal, it is undoubtedly certain that it +must give way to a metal that has still greater proportions and vaster +possibilities. Strange and startling as may seem the assertion, yet I +believe it nevertheless to be true that we are approaching the period, +if not already standing upon the threshold of the day, when this magical +element will be radically supplanted, and when this valuable mineral +will be as completely superseded as the stone of the aborigines. With +all its apparent potency, it has its evident weaknesses; moisture is +everywhere at war with it, gases and temperature destroy its fiber and +its life, continued blows or motion crystallize and rob it of its +strength, and acids will devour it in a night. If it be possible to +eliminate all, or even one or more, of these qualities of weakness in +any metal, still preserving both quantity and quality, that metal will +be the metal of the future. + +The coming metal, then, to which our reference is made is aluminum, the +most abundant metal in the earth's crust. Of all substances, oxygen is +the most abundant, constituting about one-half; after oxygen comes +silicon, constituting about one-fourth, with aluminum third in all the +list of substances of the composition. Leaving out of consideration the +constituents of the earth's center, whether they be molten or gaseous, +more or less dense as the case may be, as we approach it, and confining +ourselves to the only practical phase of the subject, the crust, we find +that aluminum is beyond question the most abundant and the most useful +of all metallic substances. + +It is the metallic base of mica, feldspar, slate, and clay. Professor +Dana says: "Nearly all the rocks except limestones and many sandstones +are literally ore-beds of the metal aluminum." It appears in the gem, +assuming a blue in the sapphire, green in the emerald, yellow in the +topaz, red in the ruby, brown in the emery, and so on to the white, +gray, blue, and black of the slates and clays. It has been dubbed "clay +metal" and "silver made from clay;" also when mixed with any +considerable quantity of carbon becoming a grayish or bluish black "alum +slate." + +This metal in color is white and next in luster to silver. It has never +been found in a pure state, but is known to exist in combination with +nearly two hundred different minerals. Corundum and pure emery are ores +that are very rich in aluminum, containing about fifty-four per cent. +The specific gravity is but two and one-half times that of water; it is +lighter than glass or as light as chalk, being only one-third the weight +of iron and one-fourth the weight of silver; it is as malleable as gold, +tenacious as iron, and harder than steel, being next the diamond. Thus +it is capable of the widest variety of uses, being soft when ductility, +fibrous when tenacity, and crystalline when hardness is required. Its +variety of transformations is something wonderful. Meeting iron, or even +iron at its best in the form of steel, in the same field, it easily +vanquishes it at every point. It melts at 1,300 degrees F., or at least +600 degrees below the melting point of iron, and it neither oxidizes in +the atmosphere nor tarnishes in contact with gases. The enumeration of +the properties of aluminum is as enchanting as the scenes of a fairy +tale. + +Before proceeding further with this new wonder of science, which is +already knocking at our doors, a brief sketch of its birth and +development may be fittingly introduced. The celebrated French chemist +Lavoisier, a very magician in the science, groping in the dark of the +last century, evolved the chemical theory of combustion--the existence +of a "highly respirable gas," oxygen, and the presence of metallic bases +in earths and alkalies. With the latter subject we have only to do at +the present moment. The metallic base was predicted, yet not identified. +The French Revolution swept this genius from the earth in 1794, and +darkness closed in upon the scene, until the light of Sir Humphry Davy's +lamp in the early years of the present century again struck upon the +metallic base of certain earths, but the reflection was so feeble that +the great secret was never revealed. Then a little later the Swedish +Berzelius and the Danish Oersted, confident in the prediction of +Lavoisier and of Davy, went in search of the mysterious stranger with +the aggressive electric current, but as yet to no purpose. It was +reserved to the distinguished German Wohler, in 1827, to complete the +work of the past fifty years of struggle and finally produce the minute +white globule of the pure metal from a mixture of the chloride of +aluminum and sodium, and at last the secret is revealed--the first step +was taken. It took twenty years of labor to revolve the mere discovery +into the production of the aluminum bead in 1846, and yet with this +first step, this new wonder remained a foetus undeveloped in the womb of +the laboratory for years to come. + +Returning again to France some time during the years between 1854 and +1858, and under the patronage of the Emperor Napoleon III., we behold +Deville at last forcing Nature to yield and give up this precious +quality as a manufactured product. Rose, of Berlin, and Gerhard, in +England, pressing hard upon the heels of the Frenchman, make permanent +the new product in the market at thirty-two dollars per pound. The +despair of three-quarters of a century of toilsome pursuit has been +broken, and the future of the metal has been established. + +The art of obtaining the metal since the period under consideration has +progressed steadily by one process after another, constantly increasing +in powers of productivity and reducing the cost. These arts are +intensely interesting to the student, but must be denied more than a +reference at this time. The price of the metal may be said to have come +within the reach of the manufacturing arts already. + +A present glance at the uses and possibilities of this wonderful metal, +its application and its varying quality, may not be out of place. Its +alloys are very numerous and always satisfactory; with iron, producing a +comparative rust proof; with copper, the beautiful golden bronze, and so +on, embracing the entire list of articles of usefulness as well as works +of art, jewelry, and scientific instruments. + +Its capacity to resist oxidation or rust fits it most eminently for all +household and cooking utensils, while its color transforms the dark +visaged, disagreeable array of pots, pans, and kitchen implements into +things of comparative beauty. As a metal it surpasses copper, brass, and +tin in being tasteless and odorless, besides being stronger than either. + +It has, as we have seen, bulk without weight, and consequently may be +available in construction of furniture and house fittings, as well in +the multitudinous requirements of architecture. The building art will +experience a rapid and radical change when this material enters as a +component material, for there will be possibilities such as are now +undreamed of in the erection of homes, public buildings, memorial +structures, etc. etc., for in this metal we have the strength, +durability, and the color to give all the variety that genius may +dictate. + +And when we take a still further survey of the vast field that is +opening before us, we find in the strength without size a most desirable +assistant in all the avenues of locomotion. It is the ideal metal for +railway traffic, for carriages and wagons. The steamships of the ocean +of equal size will double their cargo and increase the speed of the +present greyhounds of the sea, making six days from shore to shore seem +indeed an old time calculation and accomplishment. A thinner as well as +a lighter plate; a smaller as well as a stronger engine; a larger as +well as a less hazardous propeller; and a natural condition of +resistance to the action of the elements; will make travel by water a +forcible rival to the speed attained upon land, and bring all the +distant countries in contact with our civilization, to the profit of +all. This metal is destined to annihilate space even beyond the dream of +philosopher or poet. + +The tensile strength of this material is something equally wonderful, +when wire drawn reaches as high as 128,000 pounds, and under other +conditions reaches nearly if not quite 100,000 pounds to the square +inch. The requirements of the British and German governments in the best +wrought steel guns reach only a standard of 70,000 pounds to the square +inch. Bridges may be constructed that shall be lighter than wooden ones +and of greater strength than wrought steel and entirely free from +corrosion. The time is not distant when the modern wonder of the +Brooklyn span will seem a toy. + +It may also be noted that this metal affords wide development in +plumbing material, in piping, and will render possible the almost +indefinite extension of the coming feature of communication and +exchange--the pneumatic tube. + +The resistance to corrosion evidently fits this metal for railway +sleepers to take the place of the decaying wooden ties. In this metal +the sleeper may be made as soft and yielding as lead, while the rail may +be harder and tougher than steel, thus at once forming the necessary +cushion and the avoidance of jar and noise, at the same time +contributing to additional security in virtue of a stronger rail. + +In conductivity this metal is only exceeded by copper, having many times +that of iron. Thus in telegraphy there are renewed prospects in the +supplanting of the galvanized iron wire--lightness, strength, and +durability. When applied to the generation of steam, this material will +enable us to carry higher pressure at a reduced cost and increased +safety, as this will be accomplished by the thinner plate, the greater +conductivity of heat, and the better fiber. + +It is said that some of its alloys are without a rival as an +anti-friction metal, and having hardness and toughness, fits it +remarkably for bearings and journals. Herein a vast possibility in the +mechanic art lies dormant--the size of the machine may be reduced, the +speed and the power increased, realizing the conception of two things +better done than one before. It is one of man's creative acts. + +From other of its alloys, knives, axes, swords, and all cutting +implements may receive and hold an edge not surpassed by the best +tempered steel. Hulot, director in the postage stamp department, Paris, +asserts that 120,000 blows will exhaust the usefulness of the cushion of +the stamp machine, and this number of blows is given in a day; and that +when a cushion of aluminum bronze was substituted, it was unaffected +after months of use. + +If we have found a metal that possesses both tensile strength and +resistance to compression; malleability and ductility--the quality of +hardening, softening, and toughening by tempering; adaptability to +casting, rolling, or forging; susceptibility to luster and finish; of +complete homogeneous character and unusually resistant to destructive +agents--mankind will certainly leave the present accomplishments as +belonging to an effete past, and, as it were, start anew in a career of +greater prospects. + +This important material is to be found largely in nearly all the rocks, +or as Prof. Dana has said, "Nearly all rocks are ore-beds of the metal." +It is in every clay bank. It is particularly abundant in the coal +measures and is incidental to the shales or slates and clays that +underlie the coal. This under clay of the coal stratum was in all +probability the soil out of which grew the vegetation of the coal +deposits. It is a compound of aluminum and other matter, and, when mixed +with carbon and transformed by the processes of geologic action, it +becomes the shale rock which we know and which we discard as worthless +slate. And it is barely possible that we have been and are still carting +to the refuse pile an article more valuable than the so greatly lauded +coal waste or the merchantable coal itself. We have seen that the best +alumina ore contains only fifty-four per cent. of metal. + +The following prepared table has been furnished by the courtesy and +kindness of Mr. Alex. H. Sherred, of Scranton. + + ALUMINA. + +Blue-black shale, Pine Brook drift 27.36 +Slate from Briggs' Shaft coal 15.93 +Black fire clay, 4 ft. thick, Nos. 4 and 5 Rolling Mill mines 23.53 +First cut on railroad, black clay above Rolling Mill 32.60 +G vein black clay, Hyde Park mines 28.67 + +It will be seen that the black clay, shale, or slate, has a constituent +of aluminum of from 15.93 per cent., the lowest, to 32.60 per cent., the +highest. Under every stratum of coal, and frequently mixed with it, are +these under deposits that are rich in the metal. When exposed to the +atmosphere, these shales yield a small deposit of alum. In the +manufacture of alum near Glasgow the shale and slate clay from the old +coal pits constitute the material used, and in France alum is +manufactured directly from the clay. + +Sufficient has been advanced to warrant the additional assertion that we +are here everywhere surrounded by this incomparable mineral, that it is +brought to the surface from its deposits deep in the earth by the +natural process in mining, and is only exceeded in quantity by the coal +itself. Taking a columnar section of our coal field, and computing the +thickness of each shale stratum, we have from twenty-five to sixty feet +in thickness of this metal-bearing substance, which averages over +twenty-five per cent. of the whole in quantity in metal. + +It is readily apparent that the only task now before us is the reduction +of the ore and the extraction of the metal. Can this be done? We answer, +it has been done. The egg has stood on end--the new world has been +sighted. All that now remains is to repeat the operation and extend the +process. Cheap aluminum will revolutionize industry, travel, comfort, +and indulgence, transforming the present into an even greater +civilization. Let us see. + +We have seen the discovery of the mere chemical existence of the metal, +we have stood by the birth of the first white globule or bead by Wohler, +in 1846, and witnesssed its introduction as a manufactured product in +1855, since which time, by the alteration and cheapening of one process +after another, it has fallen in price from thirty-two dollars per pound +in 1855 to fifteen dollars per pound in 1885. Thirty years of persistent +labor at smelting have increased the quantity over a thousandfold and +reduced the cost upward of fifty per cent. + +All these processes involve the application of heat--a mere question of +the appliances. The electric currents of Berzelius and Oersted, the +crucible of Wohler, the closed furnaces and the hydrogen gas of the +French manufacturers and the Bessemer converter apparatus of Thompson, +all indicate one direction. This metal can be made to abandon its bed in +the earth and the rock at the will of man. During the past year, the +Messrs. Cowles, of Cleveland, by their electric smelting process, claim +to have made it possible to reduce the price of the metal to below four +dollars per pound; and there is now erecting at Lockport, New York, a +plant involving one million of capital for the purpose. + +Turning from the employment of the expensive reducing agents to the +simple and sole application of heat, we are unwilling to believe that we +do not here possess in eminence both the mineral and the medium of its +reduction. Whether the electric or the reverberatory or the converter +furnace system be employed, it is surely possible to produce the result. + +To enter into consideration of the details of these constructions would +involve more time than is permitted us on this occasion. They are very +interesting. We come again naturally to the limitless consideration of +powdered fuel, concerning which certain conclusions have been reached. +In the dissociation of water into its hydrogen and oxygen, with the +mingled carbon in a powdered state, we undoubtedly possess the elements +of combustion that are unexcelled on earth, a heat-producing combination +that in both activity and power leaves little to be desired this side of +the production of the electric force and heat directly from the carbon +without the intermediary of boilers, engines, dynamos, and furnaces. + +In the hope of stimulating thought to this infinite question of proper +fuel combustion, with its attendant possibilities for man's +gratification and ambition, this advanced step is presented. The +discussion of processes will require an amount of time which I hope this +Board will not grudgingly devote to the subject, but which is impossible +at present. Do not forget that there is no single spot on the face of +the globe where nature has lavished more freely her choicest gifts. Let +us be active in the pursuit of the treasure and grateful for the +distinguished consideration. + + * * * * * + + + + +THE ORIGIN OF METEORITES. + + +On January 9, Professor Dewar delivered the sixth and last of his series +of lectures at the Royal Institution on "The Story of a Meteorite." [For +the preceding lectures, see SUPPLEMENTS 529 and 580.] He said that +cosmic dust is found on Arctic snows and upon the bottom of the ocean; +all over the world, in fact, at some time or other, there has been a +large deposit of this meteoric dust, containing little round nodules +found also in meteorites. In Greenland some time ago numbers of what +were supposed to be meteoric stones were found; they contained iron, and +this iron, on being analyzed at Copenhagen, was found to be rich in +nickel. The Esquimaux once made knives from iron containing nickel; and +as any such alloy they must have found and not manufactured, it was +supposed to be of meteoric origin. Some young physicists visited the +basaltic coast in Greenland from which some of the supposed meteoric +stones had been brought, and in the middle of the rock large nodules +were found composed of iron and nickel; it, therefore, became evident +that the earth might produce masses not unlike such as come to us as +meteorites. The lecturer here exhibited a section of the Greenland rock +containing the iron, and nickel alloy, mixed with stony crystals, and +its resemblance to a section of a meteorite was obvious. It was 21/2 times +denser than water, yet the whole earth is 51/2 times denser than water, so +that if we could go deep enough, it is not improbable that our own globe +might be found to contain something like meteoric iron. He then called +attention to the following tables: + + _Elementary Substances found in Meteorites_. + + Hydrogen. Chromium. Arsenic. + Lithium. Manganese. Vanadium? + Sodium. Iron. Phosphorus. + Potassium. Nickel. Sulphur. + Magnesium. Cobalt. Oxygen. + Calcium. Copper. Silicon. + Aluminum. Tin. Carbon. + Titanium. Antimony. Chlorine. + +_Density of Meteorites_. + + Carbonaceous (Orgueil, etc.) 1.9 to 3 + Aluminous (Java) 3.0 " 3.2 + Peridotes (Chassigny, etc.) 3.5 " -- + Ordinary type (Saint Mes) 3.1 " 3.8 + Rich in iron (Sierra de Chuco) 6.5 " 7.0 + Iron with stone (Krasnoyarsk) 7.1 " 7.8 + True irons (Caille) 7.0 " 8.0 + +_Interior of the Earth_ + + Parts + of the + radius. Density. + 0.0 11.0 + 0.1 10.3 + 0.2 9.6 + 0.3 8.9 + 0.4 8.3 + 0.5 7.8 + 0.6 7.4 + 0.7 7.1 + 0.8 6.2 + 0.9 5.0 + 1.0 2.6 + +[Illustration] + +Twice a year, said Professor Dewar, what are called "falling stars" +maybe plentifully seen; the times of their appearance are in August and +November. Although thousands upon thousands of such small meteors have +passed through our atmosphere, there is no distinct record of one having +ever fallen to the earth during these annual displays. One was said to +have fallen recently at Naples, but on investigation it turned out to be +a myth. These annual meteors in the upper air are supposed to be only +small ones, and to be dissipated into dust and vapor at the time of +their sudden heating; so numerous are they that 40,000 have been counted +in one evening, and an exceptionally great display comes about once in +331/4 years. The inference from their periodicity is, that they are small +bodies moving round the sun in orbits of their own, and that whenever +the earth crosses their orbits, thereby getting into their path, a +splendid display of meteors results. A second display, a year later, +usually follows the exceptionally great display just mentioned, +consequently the train of meteors is of great length. Some of these +meteors just enter the atmosphere of the earth, then pass out again +forever, with their direction of motion altered by the influence of the +attraction of the earth. He here called attention to the accompanying +diagram of the orbits of meteors. + +The lecturer next invited attention to a hollow globe of linen or some +light material; it was about 2 ft. or 2 ft. 6 in. in diameter, and +contained hidden within it the great electro-magnet, weighing 2 cwt., so +often used by Faraday in his experiments. He also exhibited a ball made +partly of thin iron; the globe represented the earth, for the purposes +of the experiment, and the ball a meteorite of somewhat large relative +size. The ball was then discharged at the globe from a little catapult; +sometimes the globe attracted the ball to its surface, and held it +there, sometimes it missed it, but altered its curve of motion through +the air. So was it, said the lecturer, with meteorites when they neared +the earth. Photographs from drawings, by Professor A. Herschel, of the +paths of meteors as seen by night were projected on the screen; they all +seemed to emanate from one radiant point, which, said the lecturer, is a +proof that their motions are parallel to each other; the parallel lines +seem to draw to a point at the greatest distance, for the same reason +that the rails of a straight line of railway seem to come from a distant +central point. The most interesting thing about the path of a company of +meteors is, that a comet is known to move in the same orbit; the comet +heads the procession, the meteors follow, and they are therefore, in all +probability, parts of comets, although everything about these difficult +matters cannot as yet be entirely explained; enough, however, is known +to give foundation for the assumption that meteorites and comets are not +very dissimilar. + +The light of a meteorite is not seen until it enters the atmosphere of +the earth, but falling meteorites can be vaporized by electricity, and +the light emitted by their constituents be then examined with the +spectroscope. The light of comets can be directly examined, and it +reveals the presence in those bodies of sodium, carbon, and a few other +well-known substances. He would put a piece of meteorite in the electric +arc to see what light it would give; he had never tried the experiment +before. The lights of the theater were then turned down, and the +discourse was continued in darkness; among the most prominent lines +visible in the spectrum of the meteorite, Professor Dewar specified +magnesium, sodium, and lithium. "Where do meteorites come from?" said +the lecturer. It might be, he continued, that they were portions of +exploded planets, or had been ejected from planets. In this relation, he +should like to explain the modern idea of the possible method of +construction of our own earth. He then set forth the nebular hypothesis +that at some long past time our sun and all his planets existed but as a +volume of gas, which in contracting and cooling formed a hot volume of +rotating liquid, and that as this further contracted and cooled, the +planets, and moons, and planetary rings fell off from it and gradually +solidified, the sun being left as the solitary comparatively uncooled +portion of the original nebula. In partial illustration of this, he +caused a little globe of oil, suspended in an aqueous liquid of nearly +its own specific gravity, to rotate, and as it rotated it was seen, by +means of its magnified image upon the screen, to throw off from its +outer circumference rings and little globes. + + * * * * * + + + + +CANDELABRA CACTUS AND CALIFORNIA WOODPECKER. + +By C.F. HOLDER. + + +One of the most picturesque objects that meet the eye of the traveler +over the great plains of the southern portion of California and New +Mexico is the candelabra cactus. Systematically it belongs to the Cereus +family, in which the notable Night-blooming Cereus also is naturally +included. In tropical or semi-tropical countries these plants thrive, +and grow to enormous size. For example, the Cereus that bears those +great flowers, and blooms at night, exhaling powerful perfume, as we see +them in hothouses in our cold climate, are even in the semi-tropical +region of Key West, on the Florida Reef, seen to grow enormously in +length. + +[Illustration: THE CANDELABRA CACTUS--CEREUS GIGANTEUS.] + +We cultivated several species of the more interesting forms during a +residence on the reef. Our brick house, two stories in height, was +entirely covered on a broad gable end, the branches more than gaining +the top. There is a regular monthly growth, and this is indicated by a +joint between each two lengths. Should the stalk be allowed to grow +without support, it will continue growing without division, and exhibit +stalks five or six feet in length, when they droop, and fall upon the +ground. + +Where there is a convenient resting place on which it can spread out and +attach itself, the stalk throws out feelers and rootlets, which fasten +securely to the wall or brickwork; then, this being a normal growth, +there is a separation at intervals of about a foot. That is, the stalk +grows in one month about twelve inches, and if it has support, the +middle woody stalk continues to grow about an inch further, but has no +green, succulent portion, in fact, looks like a stem; then the other +monthly growth takes place, and ends with a stem, and so on +indefinitely. Our house was entirely covered by the stems of such a +plant, and the flowers were gorgeous in the extreme. The perfume, +however, was so potent that it became a nuisance. Such is the +Night-blooming Cereus in the warm climates, and similarly the Candelabra +Cereus grows in stalks, but architecturally erect, fluted like columns. +The flowers are large, and resemble those of the night-blooming variety. +Some columns remain single, and are amazingly artificial appearing; +others throw off shoots, as seen in the picture. There are some smaller +varieties that have even more of a candelabra look, there being clusters +of side shoots, the latter putting out from the trunk regularly, and +standing up parallel to each other. The enormous size these attain is +well shown in the picture. + +Whenever the great stalks of these cacti die, the succulent portion is +dried, and nothing is left but the woody fiber. They are hollow in +places, and easily penetrated. A species of woodpecker, _Melanerpes +formicivorus_, is found to have adopted the use of these dry stalks for +storing the winter's stock of provisions. There are several round +apertures seen on the stems in the pictures, which were pecked by this +bird. This species of woodpecker is about the size of our common robin +or migratory thrush, and has a bill stout and sharp. The holes are +pecked for the purpose of storing away acorns or other nuts; they are +just large enough to admit the fruit, while the cup or larger end +remains outside. The nuts are forced in, so that it requires +considerable wrenching to dislodge them. In many instances the nuts are +so numerous, the stalk has the appearance of being studded with bullets. +This appearance is more pronounced in cases where the dead trunk of an +oak is used. There are some specimens of the latter now owned by the +American Museum of Natural History, which were originally sent to the +Centennial Exhibition at Philadelphia. They were placed in the +department contributed by the Pacific Railroad Company, and at that time +were regarded as some of the wonders of that newly explored region +through which the railroad was then penetrating. Some portions of the +surface of these logs are nearly entirely occupied by the holes with +acorns in them. The acorns are driven in very tightly in these examples; +much more so than in the cactus plants, as the oak is nearly round, and +the holes were pecked in solid though dead wood. One of the most +remarkable circumstances connected with this habit of the woodpecker is +the length of flight required and accomplished. At Mount Pizarro, where +such storehouses are found, the nearest oak trees are in the +Cordilleras, thirty miles distant; thus the birds are obliged to make a +journey of sixty miles to accomplish the storing of one acorn. At first +it seemed strange that a bird should spend so much labor to place those +bits of food, and so far away. De Saussure, a Swiss naturalist, +published in the _Bibliotheque Universelle_, of Geneva, entertaining +accounts of the Mexican Colaptes, a variety of the familiar "high hold," +or golden winged woodpecker. They were seen to store acorns in the dead +stalks of the maguey (_Agave Americana_). Sumichrast, who accompanied +him to Central America, records the same facts. These travelers saw +great numbers of the woodpeckers in a region on the slope of a range of +volcanic mountains. There was little else of vegetation than the +_Agave_, whose barren, dead stems were studded with acorns placed there +by the woodpeckers. + +The maguey throws up a stalk about fifteen feet in height yearly, which, +after flowering, grows stalky and brittle, and remains an unsightly +thing. The interior is pithy, but after the death of the stalk the pith +contracts, and leaves the greater portion of the interior hollow, as we +have seen in the case of the cactus branches. How the birds found that +these stalks were hollow is a problem not yet solved, but, nevertheless, +they take the trouble to peck away at the hard bark, and once +penetrated, they commence to fill the interior; when one space is full, +the bird pecks a little higher up, and so continues. + +Dr. Heerman, of California, describes the California _Melanerpes_ as one +of the most abundant of the woodpeckers; and remarks that it catches +insects on the wing like a flycatcher. It is well determined that it +also eats the acorns that it takes so much pains to transport. + +[Illustration: FLOWER OF CEREUS GIGANTEUS.] + +It seems that these birds also store the pine trees, as well as the +oaks. It is not quite apparent why these birds exhibit such variation in +habits; they at times select the more solid trees, where the storing +cannot go on without each nut is separately set in a hole of its own. +There seems an instinct prompting them to do this work, though there may +not be any of the nuts touched again by the birds. Curiously enough, +there are many instances of the birds placing pebbles instead of nuts in +holes they have purposely pecked for them. Serious trouble has been +experienced by these pebbles suddenly coming in contact with the saw of +the mill through which the tree is running. The stone having been placed +in a living tree, as is often the case, its exterior had been lost to +sight during growth. + +Some doubt has been entertained about the purpose of the bird in storing +the nuts in this manner. De Saussure tells us he has witnessed the birds +eating the acorns after they had been placed in holes in trees, and +expresses his conviction that the insignificant grub which is only seen +in a small proportion of nuts is not the food they are in search of. + +C.W. Plass, Esq., of Napa City, California, had an interesting example +of the habits of the California _Melanerpes_ displayed in his own house. +The birds had deposited numbers of acorns in the gable end. A +considerable number of shells were found dropped underneath the eaves, +while some were found in place under the gable, and these were perfect, +having no grubs in them. + +The picture shows a very common scene in New Mexico. The columns, +straight and angular, are often sixty feet in height. It is called torch +cactus in some places. There are many varieties, and as many different +shapes. Some lie on the ground; others, attached to trunks of trees as +parasites, hang from branches like great serpents; but none is so +majestic as the species called systematically _Cereus giganteus_, most +appropriately. The species growing pretty abundantly on the island of +Key West is called candle cactus. It reaches some ten or twelve feet, +and is about three inches in diameter. The angles are not so prominent, +which gives the cylinders a roundish appearance. They form a pretty, +rather picturesque feature in the otherwise barren undergrowth of +shrubbery and small trees. Accompanied by a few flowering cocoa palms, +the view is not unpleasing. The fiber of these plants is utilized in +some coarse manufactures. The maguey, or Agave, is used in the +manufacture of fine roping. Manila hemp is made from a species. The +species whose dried stalks are used by the woodpeckers for their winter +storage was cultivated at Key West, Florida, during several years before +1858. Extensive fields of the Agave stood unappropriated at that period. +Considerable funds were dissipated on this venture. Extensive works were +established, and much confidence was entertained that the scheme would +prove a paying one, but the "hemp" rope which this was intended to rival +could be made cheaper than this. The great Agave plants, with their long +stalks, stand now, increasing every year, until a portion of the island +is overrun with them. + + +CEREUS GIGANTEUS. + +This wonderful cactus, its colossal proportions, and weird, yet grand, +appearance in the rocky regions of Mexico and California, where it is +found in abundance, have been made known to us only through books of +travel, no large plants of it having as yet appeared in cultivation in +this country. It is questionable if ever the natural desire to see such +a vegetable curiosity represented by a large specimen in gardens like +Kew can be realized, owing to the difficulty of importing large stems in +a living condition; and even if successfully brought here, they survive +only a very short time. To grow young plants to a large size seems +equally beyond our power, as plants 6 inches high and carefully managed +are quite ten years old. When young, the stem is globose, afterward +becoming club-shaped or cylindrical. It flowers at the height of 12 +feet, but grows up to four or five times that height, when it develops +lateral branches, which curve upward and present the appearance of an +immense candelabrum, the base of the stem being as thick as a man's +body. The flower, of which a figure is given here, is about 5 inches +long and wide, the petals cream colored, the sepals greenish white. +Large clusters of flowers are developed together near the top of the +stem. A richly colored edible fruit like a large fig succeeds each +flower, and this is gathered by the natives and used as food under the +name of saguarro. A specimen of this cactus 3 feet high may be seen in +the succulent house at Kew.--_B., The Garden_. + + * * * * * + + + + +HOW PLANTS ARE REPRODUCED. + +[Footnote: Read at a meeting of the Chemists' Assistants' Association. +December 16, 1885.] + +By C.E. STUART, B.Sc. + + +In two previous papers read before this Association I have tried to +condense into as small a space as I could the processes of the nutrition +and of the growth of plants; in the present paper I want to set before +you the broad lines of the methods by which plants are reproduced. + +Although in the great trees of the conifers and the dicotyledons we have +apparently provision for growth for any number of years, or even +centuries, yet accident or decay, or one of the many ills that plants +are heirs to, will sooner or later put an end to the life of every +individual plant. + +Hence the most important act of a plant--not for itself perhaps, but for +its race--is the act by which it, as we say, "reproduces itself," that +is, the act which results in the giving of life to a second individual +of the same form, structure, and nature as the original plant. + +The methods by which it is secured that the second generation of the +plant shall be as well or even better fitted for the struggle of life +than the parent generation are so numerous and complicated that I cannot +in this paper do more than allude to them; they are most completely seen +in cross fertilization, and the adaptation of plant structures to that +end. + +What I want to point out at present are the principles and not so much +the details of reproduction, and I wish you to notice, as I proceed, +what is true not only of reproduction in plants but also of all +processes in nature, namely, the paucity of typical methods of attaining +the given end, and the multiplicity of special variation from those +typical methods. When we see the wonderfully varied forms of plant life, +and yet learn that, so to speak, each edifice is built with the same +kind of brick, called a cell, modified in form and function; when we see +the smallest and simplest equally with the largest and most complicated +plant increasing in size subject to the laws of growth by +intussusception and cell division, which are universal in the organic +world; we should not be surprised if all the methods by which plants are +reproduced can be reduced to a very small number of types. + +The first great generalization is into-- + +1. The vegetative type of reproduction, in which one or more ordinary +cells separate from the parent plant and become an independent plant; +and-- + +2. The special-cell type of reproduction, in which either one special +cell reproduces the plant, or two special cells by their union form the +origin of the new plant; these two modifications of the process are +known respectively as asexual and sexual. + +The third modification is a combination of the two others, namely, the +asexual special cell does not directly reproduce its parent form, but +gives rise to a structure in which sexual special cells are developed, +from whose coalescence springs again the likeness of the original plant. +This is termed alternation of generations. + +The sexual special cell is termed the _spore_. + +The sexual special cells are of one kind or of two kinds. + +Those which are of one kind may be termed, from their habit of yoking +themselves together, _zygoblasts_, or conjugating cells. + +Those which are of two kinds are, first, a generally aggressive and +motile fertilizing or so-called "male cell," called in its typical form +an _antherozoid_; and, second, a passive and motionless receptive or +so-called "female cell," called an _oosphere_. + +The product of the union of two zygoblasts is termed a _zygospore_. + +The product of the union of an antherozoid and an oosphere is termed an +_oospore_. + +In many cases the differentiation of the sexual cells does not proceed +so far as the formation of antherozoids or of distinct oospheres; these +cases I shall investigate with the others in detail presently. + +First, then, I will point out some of the modes of vegetative +reproduction. + +The commonest of these is cell division, as seen in unicellular plants, +such as protococcus, where the one cell which composes the plant simply +divides into two, and each newly formed cell is then a complete plant. + +The particular kind of cell division termed "budding" here deserves +mention. It is well seen in the yeast-plant, where the cell bulges at +one side, and this bulge becomes larger until it is nipped off from the +parent by contraction at the point of junction, and is then an +independent plant. + +Next, there is the process by which one plant becomes two by the dying +off of some connecting portion between two growing parts. + +Take, for instance, the case of the liverworts. In these there is a +thallus which starts from a central point and continually divides in a +forked or dichotomous manner. Now, if the central portion dies away, it +is obvious that there will be as many plants as there were forkings, and +the further the dying of the old end proceeds, the more young plants +will there be. + +Take again, among higher plants, the cases of suckers, runners, stolons, +offsets, etc. Here, by a process of growth but little removed from the +normal, portions of stems develop adventitious roots, and by the dying +away of the connecting links may become independent plants. + +Still another vegetative method of reproduction is that by bulbils or +gemmae. + +A bulbil is a bud which becomes an independent plant before it commences +to elongate; it is generally fleshy, somewhat after the manner of a +bulb, hence its name. Examples occur in the axillary buds of _Lilium +bulbiferum_, in some _Alliums_, etc. + +The gemma is found most frequently in the liverworts and mosses, and is +highly characteristic of these plants, in which indeed vegetative +reproduction maybe said to reach its fullest and most varied extent. + +Gemmae are here formed in a sort of flat cup, by division of superficial +cells of the thallus or of the stem, and they consist when mature of +flattened masses of cells, which lie loose in the cup, so that wind or +wet will carry them away on to soil or rock, when, either by direct +growth from apical cells, as with those of the liverworts, or with +previous emission of thread-like cells forming a "protonema," in the +case of the mosses, the young plant is produced from them. + +The lichens have a very peculiar method of gemmation. The lichen-thallus +is composed of chains or groups of round chlorophyl-containing cells, +called "gonidia," and masses of interwoven rows of elongated cells which +constitute the hyphae. Under certain conditions single cells of the +gonidia become surrounded with a dense felt of hyphae, these accumulate +in numbers below the surface of the thallus, until at last they break +out, are blown or washed away, and start germination by ordinary cell +division, and thus at once reproduce a fresh lichen-thallus. These +masses of cells are called soredia. + +Artificial budding and grafting do not enter into the scope of this +paper. + +As in the general growth and the vegetative reproduction of plants +cell-division is the chief method of cell formation, so in the +reproduction of plants by special cells the great feature is the part +played by cells which are produced not by the ordinary method of cell +division, but by one or the other processes of cell formation, namely, +free-cell formation or rejuvenescence. + +If we broaden somewhat the definition of rejuvenescence and free-cell +formation, and do not call the mother-cells of spores of mosses, higher +cryptogams, and also the mother-cells of pollen-grains, reproductive +cells, which strictly speaking they are not, but only producers of the +spores or pollen-grains, then we may say that _cell-division is confined +to vegetative processes, rejuvenescence and free-cell formation are +confined to reproductive processes_. + +Rejuvenescence may be defined as the rearrangement of the whole of the +protoplasm of a cell into a new cell, which becomes free from the +mother-cell, and may or may not secrete a cell-wall around it. + +If instead of the whole protoplasm of the cell arranging itself into one +mass, it divides into several, or if portions only of the protoplasm +become marked out into new cells, in each case accompanied by rounding +off and contraction, the new cells remaining free from one another, and +usually each secreting a cell wall, then this process, whose relation to +rejuvenescence is apparent, is called free-cell formation. + +The only case of purely vegetative cell-formation which takes place by +either of these processes is that of the formation of endosperm in +Selaginella and phanerogams, which is a process of free-cell formation. + +On the other hand, the universal contraction and rounding off of the +protoplasm, and the formation by either rejuvenescence or free-cell +formation, distinctly mark out the special or true reproductive cell. + +Examples of reproductive cells formed by rejuvenescence are: + +1. The swarm spores of many algae, as Stigeoclonium (figured in Sachs' +"Botany"). Here the contents of the cell contract, rearrange themselves, +and burst the side of the containing wall, becoming free as a +reproductive cell. + +2. The zygoblasts of conjugating algae, as in Spirogyra. Here the +contents of a cell contract and rearrange themselves only after contact +of the cell with one of another filament of the plant. This zygoblast +only becomes free after the process of conjugation, as described below. + +3. The oosphere of characeae, mosses and liverworts, and vascular +cryptogams, where in special structures produced by cell-divisions there +arise single primordial cells, which divide into two portions, of which +the upper portion dissolves or becomes mucilaginous, while the lower +contracts and rearranges itself to form the oosphere. + +4. Spores of mosses and liverworts, of vascular cryptogams, and pollen +cells of phanerogams, which are the analogue of the spores. + +The type in all these cases is this: A mother-cell produces by +cell-division four daughter-cells. This is so far vegetative. Each +daughter-cell contracts and becomes more or less rounded, secretes a +wall of its own, and by the bursting or absorption of the wall of its +mother-cell becomes free. This is evidently a rejuvenescence. + +Examples of reproductive cells formed by free-cell formation are: + +1. The ascospores of fungi and algae. + +2. The zoospores or mobile spores of many algae and fungi. + +3. The germinal vesicles of phanerogams. + +The next portion of my subject is the study of the methods by which +these special cells reproduce the plant. + +1st. Asexual methods. + +1. Rejuvenescence gives rise to a swarm-spore or zoospore. The whole of +the protoplasm of a cell contracts, becomes rounded and rearranged, and +escapes into the water, in which the plant floats as a mass of +protoplasm, clear at one end and provided with cilia by which it is +enabled to move, until after a time it comes to rest, and after +secreting a wall forms a new plant by ordinary cell-division. Example: +Oedogonium. + +2. Free-cell formation forms swarm-spores which behave as above. +Example: Achlya. + +3. Free-cell formation forms the typical motionless spore of algae and +fungi. For instance, in the asci of lichens there are formed from a +portion of the protoplasm four or more small ascospores, which secrete a +cell-wall and lie loose in the ascus. Occasionally these spores may +consist of two or more cells. They are set free by the rupture of the +ascus, and germinate by putting out through their walls one or more +filaments which branch and form the thallus of a new individual. Various +other spores formed in the same way are known as _tetraspores_, etc. + +4. Cell-division with rejuvenescence forms the spores of mosses and +higher cryptogams. + +To take the example of moss spores: + +Certain cells in the sporogonium of a moss are called mother-cells. The +protoplasm of each one of these becomes divided into four parts. Each of +these parts then secretes a cell-wall and becomes free as a spore by the +rupture or absorption of the wall of the mother-cell. The germination of +the spores I shall describe later. + +5. A process of budding which in the yeast plant and in mosses is merely +vegetatively reproductive, in fungi becomes truly reproductive, namely, +the buds are special cells arising from other special cells of the +hyphae. + +For example, the so-called "gills" of the common mushroom have their +surface composed of the ends of the threads of cells constituting the +hyphae. Some of these terminal cells push out a little finger of +protoplasm, which swells, thickens its wall, and becomes detached from +the mother-cell as a spore, here called specially a _basidiospore_. + +Also in the common gray mould of infusions and preserves, Penicillium, +by a process which is perhaps intermediate between budding and +cell-division, a cell at the end of a hypha constricts itself in several +places, and the constricted portions become separate as _conidiospores_. + +_Teleutospores, uredospores_, etc., are other names for spores similarly +formed. + +These conidiospores sometimes at once develop hyphae, and sometimes, as +in the case of the potato fungus, they turn out their contents as a +swarm-spore, which actively moves about and penetrates the potato leaves +through the stomata before they come to rest and elongate into the +hyphal form. + +So far for asexual methods of reproduction. + +I shall now consider the sexual methods. + +The distinctive character of these methods is that the cell from which +the new individual is derived is incapable of producing by division or +otherwise that new individual without the aid of the protoplasm of +another cell. + +Why this should be we do not know; all that we can do is to guess that +there is some physical or chemical want which is only supplied through +the union of the two protoplasmic masses. The process is of benefit to +the species to which the individuals belong, since it gives it a greater +vigor and adaptability to varying conditions, for the separate +peculiarities of two individuals due to climatic or other conditions are +in the new generation combined in one individual. + +The simplest of the sexual processes is conjugation. Here the two +combining cells are apparently of precisely similar nature and +structure. I say apparently, because if they are really alike it is +difficult to see what is gained by the union. + +Conjugation occurs in algae and fungi. A typical case is that of +Spirogyra. This is an alga with its cells in long filaments. Two +contiguous cells of two parallel filaments push each a little projection +from its cell-wall toward the other. When these meet, the protoplasm of +each of the two cells contracts, and assumes an elliptical form--it +undergoes rejuvenescence. Next an opening forms where the two cells are +in contact, and the contents of one cell pass over into the other, where +the two protoplasmic bodies coalesce, contract, and develop a cell-wall. +The zygospore thus formed germinates after a long period and forms a new +filament of cells. + +Another example of conjugation is that of Pandorina, an alga allied to +the well-known volvox. Here the conjugating cells swim free in water; +they have no cell-wall, and move actively by cilia. Two out of a number +approach, coalesce, contract, and secrete a cell-wall. After a long +period of rest, this zygospore allows the whole of its contents to +escape as a swarm-spore, which after a time secretes a gelatinous wall, +and by division reproduces the sixteen-celled family. + +We now come to fertilization, where the uniting cells are of two kinds. + +The simplest case is that of Vaucheria, an alga. Here the vegetative +filament puts out two protuberances, which become shut off from the body +of the filament by partitions. The protoplasm in one of these +protuberances arranges itself into a round mass--the oosphere or female +cell. The protoplasm of the other protuberance divides into many small +masses, furnished with cilia, the spermatozoids or male cells. Each +protuberance bursts, and some of the spermatozoids come in contact with +and are absorbed by the oosphere, which then secretes a cell-wall, and +after a time germinates. + +The most advanced type of fertilization is that of angiosperms. + +In them there are these differences from the above process: the contents +of the male cell, represented by the pollen, are not differentiated into +spermatozoids, and there is no actual contact between the contents of +the pollen tube and the germinal vesicle, but according to Strashurger, +there is a transference of the substance of the nucleus of the pollen +cell to that of the germinal vesicle by osmose. The coalescence of the +two nuclei within the substance of the germinal vesicle causes the +latter to secrete a wall, and to form a new plant by division, being +nourished the while by the mother plant, from whose tissues the young +embryo plant contained in the seed only becomes free when it is in an +advanced stage of differentiation. + +Perhaps the most remarkable cases of fertilization occur in the Florideae +or red seaweeds, to which class the well-known Irish moss belongs. + +Here, instead of the cell which is fertilized by the rounded +spermatozoid producing a new plant through the medium of spores, some +other cell which is quite distinct from the primarily fertilized cell +carries on the reproductive process. + +If the allied group of the Coleochaeteae is considered together with the +Florideae, we find a transition between the ordinary case of Coleochaete +and that of Dudresnaya. In Coleochaete, the male cell is a round +spermatozoid, and the female cell an oosphere contained in the base of a +cell which is elongated into an open and hair-like tube called the +trichogyne. The spermatozoid coalesces with the oosphere, which secretes +a wall, becomes surrounded with a covering of cells called a cystocarp, +which springs from cells below the trichogyne, and after the whole +structure falls from the parent plant, spores are developed from the +oospore, and from them arises a new generation. + +In Dudresnaya, on the other hand, the spermatozoid coalesces indeed with +the trichogyne, but this does not develop further. From below the +trichogyne, however, spring several branches, which run to the ends of +adjacent branches, with the apical cells of which they conjugate, and +the result of this conjugation is the development of a cystocarp similar +to that of Coleochaete. The remarkable point here is the way in which the +effect of the fertilizing process is carried from one cell to another +entirely distinct from it. + +Thus I have endeavored to sum up the processes of asexual and of sexual +reproduction. But it is a peculiar characteristic of most classes of +plants that the cycle of their existence is not complete until both +methods of reproduction have been called into play, and that the +structure produced by one method is entirely different from that +produced by the other method. + +Indeed, it is only in some algae and fungi that the reproductive cells of +one generation produce a generation similar to the parent; in all other +plants a generation A produces are unlike generation B, which may either +go on to produce another generation, C, and then back to A, or it may go +on producing B's until one of these reproduces A, or again it may +directly reproduce; A. Thus we have the three types: + + 1. A-B-C.--A-B-C.--A..................... etc. + 2. A-B-B.--B-B...................B--A ... etc. + 3. A B A B A............................. etc. + +The first case is not common, the usual number of generations being two +only; but a typical example of the occurrence of three generations is in +such fungi as _Puccinia Graminis_. Here the first generation grows on +barberry leaves, and produces a kind of spore called an _aecidium spore_. +These aecidium spores germinate only on a grass stem or leaf, and a +distinct generation is produced, having a particular kind of spore +called an _uredospore_. The uredospore forms fresh generations of the +same kind until the close of the summer, when the third generation with +another kind of spore, called a _teleutospore_, is produced. + +The teleutospores only germinate on barberry leaves, and there reproduce +the original aecidium generation. + +Thus we have the series A.B.B.B ... BCA + +In this instance all the generations are asexual, but the most common +case is for the sexual and the asexual generations to alternate. I will +describe as examples the reproduction of a moss, a fern, and a +dicotyledon. + +In such a typical moss as Funaria, we have the following cycle of +developments: The sexual generation is a dioecious leafy structure, +having a central elongated axis, with leaves arranged regularly around +and along it. At the top of the axis in the male plant rise the +antheridia, surrounded by an envelope of modified leaves called the +perigonium. The antheridia are stalked sacs, with a single wall of +cells, and the spiral antherozoids arise by free-cell formation from the +cells of the interior. They are discharged by the bursting of the +antheridium, together with a mucilage formed of the degraded walls of +their mother cells. + +In the female plant there arise at the apex of the stem, surrounded by +an envelope of ordinary leaves, several archegonia. These are of the +ordinary type of those organs, namely, a broad lower portion, containing +a naked oosphere and a long narrow neck with a central canal leading to +the oosphere. Down this canal pass one or more antherozoids, which +become absorbed into the oosphere, and this then secretes a wall, and +from it grows the second or asexual generation. The peculiarity of this +asexual or spore-bearing plant is that it is parasitic on the sexual +plant; the two generations, although not organically connected, yet +remain in close contact, and the spore-bearing generation is at all +events for a time nourished by the leafy sexual generation. + +The spore-bearing generation consists of a long stalk, closely held +below by the cells of the base of the archegonium; this supports a +broadened portion which contains the spores, and the top is covered with +the remains of the neck of the archegonium forming the calyptra. + +The spores arise from special or mother-cells by a process of division, +or it may be even termed free-cell formation, the protoplasm of each +mother-cell dividing into four parts, each of which contracts, secretes +a wall, and thus by rejuvenescence becomes a spore, and by the +absorption of the mother-cells the spores lie loose in the spore sac. +The spores are set free by the bursting of their chamber, and each +germinates, putting out a branched thread of cells called a protonema, +which may perhaps properly be termed a third generation in the cycle of +the plant; for it is only from buds developed on this protonema that the +leafy sexual plant arises. + +The characteristics, then, of the mosses are, that the sexual generation +is leafy, the one or two asexual generations are thalloid, and that the +spore-bearing generation is in parasitic connection with the sexual +generation. + +In the case of the fern, these conditions are very different. + +The sexual generation is a small green thalloid structure called a +prothallium, which bears antheridia and archegonia, each archegonium +having a neck-canal and oosphere, which is fertilized just as in the +moss. + +But the asexual generation derived from the oospore only for a short +while remains in connection with the prothallium, which, of course, +answers to the leafy portion of the moss. What is generally known as the +fern is this asexual generation, a great contrast to the small leafless +moss fruit or sporogonium as it is called, to which it is +morphologically equivalent. On the leaves of this generation arise the +sporangia which contain the spores. The spores are formed in a manner +very similar to those of the mosses, and are set free by rupture of the +sporangium. + +The spore produces the small green prothallium by cell-division in the +usual way, and this completes the cycle of fern life. + +The alternation of generations, which is perhaps most clear and typical +in the case of the fern, becomes less distinctly marked in the plants of +higher organization and type. + +Thus in the Rhizocarpae there are two kinds of spores, _microspores_ and +_macrospores_, producing prothallia which bear respectively antheridia +and archegonia; in the Lycopodiaceae, the two kinds of spores produce +very rudimentary prothallia; in the cycads and conifers, the microspore +or pollen grain only divides once or twice, just indicating a +prothallium, and no antheridia or antherozoids are formed. The +macrospore or embryo-sac produces a prothallium called the endosperm, in +which archegonia or corpuscula are formed; and lastly, in typical +dicotyledons it is only lately that any trace of a prothallium from the +microspore or pollen cell has been discovered, while the macrospore or +embryo-sac produces only two or three prothallium cells, known as +antipodal cells, and two or three oospheres, known as germinal vesicles. + +This description of the analogies of the pollen and embryo-sac of +dicotyledons assumes that the general vegetative structure of this class +of plants is equivalent to the asexual generation of the higher +cryptogams. In describing their cycle of reproduction I will endeavor to +show grounds for this assumption. + +We start with the embryo as contained in the seed. This embryo is the +product of fertilization of a germinal vesicle by a pollen tube. Hence, +by analogy with the product of fertilization of rhizocarp's, ferns, and +mosses, it should develop into a spore bearing plant. It does develop +into a plant in which on certain modified leaves are produced masses of +tissue in which two kinds of special reproductive cells are formed. This +is precisely analogous to the case of gymnosperms, lycopods, etc., where +on leaf structures are formed macro and micro sporangia. + +To deal first with the microsporangium or pollen-sac. The pollen cells +are formed from mother cells by a process of cell division and +subsequent setting free of the daughter cells or pollen cells by +rejuvenescence, which is distinctly comparable with that of the +formation of the microspores of Lycopodiaceae, etc. The subsequent +behavior of the pollen cell, its division and its fertilization of the +germinal vesicle or oosphere, leave no doubt as to its analogy with the +microspore of vascular cryptogams. + +Secondly, the nucleus of the ovule corresponds with the macrosporangium +of Selaginella, through the connecting link of the conifers, where the +ovule is of similar origin and position to the macrosporangium of the +Lycopodiaceae. But the formation of the macrospore or embryo-sac is +simpler than the corresponding process in cryptogams. It arises by a +simple enlargement of one cell of the nucleus instead of by the division +of one cell into four, each thus becoming a macrospore. At the top of +this macrospore or embryo-sac two or three germinal vesicles are formed +by free cell formation, and also two or three cells called antipodal +cells, since they travel to the other end of the embryo-sac; these +latter represent a rudimentary prothallium. This formation of germinal +vesicles and prothallium seems very different from the formation of +archegonia and prothallium in Selaginella, for instance; but the link +which connects the two is in the gymnosperms, where distinct archegonia +in a prothallium are formed. + +Thus we see that the flowering plant is essentially the equivalent of +the asexual fern, and of the sporogonium of the moss, and the pollen +cell and the embryo-sac represent the two spores of the higher +cryptogams, and the pollen tube and the germinal vesicles and antipodal +cells are all that remain of the sexual generation, seen in the moss as +a leafy plant, and in the fern as a prothallium. Indeed, when a plant +has monoecious or dioecious flowers, the distinction between the asexual +and the sexual generation has practically been lost, and the +spore-bearing generation has become identified with the sexual +generation. + +Having now described the formation of the pollen and the germinal +vesicles, it only remains to show how they form the embryo. The pollen +cell forms two or three divisions, which are either permanent or soon +absorbed; this, as before stated, is the rudimentary male prothallium. +Then when it lies on the stigma it develops a long tube, which passes +down the style and through the micropyle of the ovule to the germinal +vesicles, one of which is fertilized by what is probably an osmotic +transference of nuclear matter. The germinal vesicle now secretes a +wall, divides into two parts, and while the rest of the embyro-sac fills +with endosperm cells, it produces by cell division from the upper half a +short row of cells termed a suspensor, and from the lower half a mass of +cells constituting the embryo. Thus while in the moss the asexual +generation or sporogonium is nourished by the sexual generation or leafy +plant, and while in the fern each generation is an independent +structure, here in the dicotyledon, on the other hand, the asexual +generation or embryo is again for a time nourished in the interior of +the embryo-sac representing the sexual generation, and this again +derives its nourishment from the previous asexual generation, so that as +in the moss, there is again a partial parasitism of one generation on +the other. + +To sum up the methods of plant reproduction: They resolve themselves +into two classes. + +1st. Purely vegetative. + +2d. Truly reproductive by special cells. + +In the second class, if we count conjugation as a simple form of +fertilization, there are only two types of reproductive methods. + +1st. Reproduction from an asexual spore. + +2d. Reproduction from an oospore formed by the combination of two sexual +cells. + +In the vast majority of plant species these two types are used by the +individuals alternately. + +The extraordinary similarity of the reproductive process, as shown in +the examples I have given, Achlya, Spirogyra, and Vaucheria among algae, +the moss, the fern, and the flowering plant, a similarity which becomes +the more marked the more the details of each case and of the cases of +plants which form links between these great classes are studied, points +to a community of origin of all plants in some few or one primeval +ancestor. And to this inference the study of plant structure and +morphology, together with the evidence of palaeobotany among other +circumstances, lends confirmatory evidence, and all modern discoveries, +as for instance that of the rudimentary prothallium formed by the pollen +of angiosperms, tend to the smoothing of the path by which the descent +of the higher plants from simpler types will, as I think, be eventually +shown. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +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. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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