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+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: 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.
+
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