Chapter 1

SCIENTIFIC AMERICAN SUPPLEMENT NO. 601

NEW YORK, JULY 9, 1887

Scientific American Supplement. Vol. XXIV, No. 601.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.

I. ASTRONOMY.--A Star Finder.--A simple apparatus that can be constructed by any mechanic.--1 illustration.

Photographic Study of Stellar Spectra, Harvard College Observatory. --First annual report of the Henry Draper memorial observations. --Review of the work by Prof. EDWARD C. PICKERING.

II. BIOLOGY.--Sponges.--The growth and life history of sponges.--Report of a recent lecture at the London Royal Institution by Dr. R. VON LEDENFELD.

III. ELECTRICITY.--Phenomena of Alternating Currents.--By Prof. ELIHU THOMSON.--16 illustrations.

IV. ENGINEERING.--An English Car Coupling.--Description of an English automatic coupling.--2 illustrations.

A New Process of Casting Iron and other Metals upon Lace, Embroideries, Fern Leaves, and other Combustible Materials. --By A.E. OUTERBRIDGE, JR.--A new and eminently practical process of producing ornamental castings.--4 illustrations.

Bricks and Brick Work.--By Prof. T. ROGER SMITH, F.R.I.B.A. --The history and technical review of this subject.--A most remarkable contribution to the engineering of architecture.

Link Belting.--By CHARLES A. SCHIEREN.--An interesting and practical paper on leather belting made of links. --9 illustrations.

Recent Progress in Gas Engineering.--A lecture by Mr. A. MACPHERSON, of Kirkcaldy, reviewing the last improvements in this branch.

V. MISCELLANEOUS.--Herbet's Tepid Douche.--Apparatus in use for bathing soldiers in the French barracks.--1 illustration.

Kent's Torsion Balance.--A new type of balance, involving torsional suspension instead of knife edges.--5 illustrations.

Preservative Liquid.--Note on preservation of organic substances.

The Falls of Gairsoppa.--The great Indian falls, higher than Niagara.--2 illustrations.

The New British Coinage and Jubilee Medal.--Illustrations and descriptions of the new pieces.--8 illustrations.

The Winner of the Derby.--Portrait and description of Merry Hampton.

VI. NAVAL ENGINEERING.--The Falke Type Torpedo Boat.--The fastest type of British torpedo boat, constructed by Messrs. Yarrow & Co.--1 illustration.

The German Navy.--The New Gunboat Eber.--A description of a late accession to the German navy.--1 illustration.

VII. ORDNANCE AND GUNNERY.--Magazine Rifles.--Continuation of this important article, including the Chaffee-Reece, Kropatschek, and other magazine guns.--3 illustrations.

New British Torpedo Experiments.--Experiments with torpedoes against a ship.--The efficiency or torpedo nets.--The effects of Whitehead torpedoes.

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THE FALKE TYPE TORPEDO BOAT.

Among the different classes of vessels designed for special services, constructed by Messrs. Yarrow & Co., at Poplar, for the British government, is one which is stated to be the fastest torpedo boat in her majesty's navy. This boat has been put through its official trials; with a load of 15 tons, running continuously for two hours without stopping, a speed of 23 knots, which is equal to 26½ statute miles, an hour was obtained. The boat is 135 ft. long by 14 ft. beam. Its design is known as the Falke type, being in many respects similar, but very superior, to a torpedo boat of that name which was built two years ago by the same firm for the Austrian government. The form of the hull is of such a character as to give exceptional steering capabilities; at the time of trial it was found to be able to steer round in a circle of a diameter of 100 yards, averaging 62 seconds. The forward part of the boat is completely covered over by a large turtle back, which is the customary form of the boats built by Messrs. Yarrow & Co. It was first introduced in the Batoum, which they constructed eight years ago for the Russian government. This turtle back increases the seaworthiness of the craft by throwing the water that comes upon it freely away. It forms, also, good and roomy accommodation for the crew, and incloses a large portion of the torpedo apparatus. The forward torpedo gear consists of one torpedo gun, adapted for ejecting the Whitehead torpedo by means of gunpowder, now preferred on account of its simplicity. The boiler, one of Messrs. Yarrow & Co.'s special construction, of a type which has undergone many years of constant trial, is capable of developing 1,660 horse power. In the engine room there are six engines--one for driving the boat, two for compressing the air for the torpedoes, an engine for working the dynamo for producing the electric light, an engine for forcing air into the stoke-hole, and an engine working in conjunction with the distilling apparatus for supplying drinking water for the crew and the waste incidental to the boiler. Aft of the engine room come the officers' quarters. The stern of the boat is fitted up as a pantry and for the stowage of ammunition and stores. On the deck are mounted three machine guns, and near the stern an additional conning tower for use in case of need, around which revolve two torpedo guns for firing the torpedoes off either side. These torpedo guns can be trained to any angle it may be desired to fire them at. On both conning towers are machine guns.--_Illustrated London News_.

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THE GERMAN NAVY--THE NEW GUNBOAT EBER.

The gunboat Eber is an improved vessel of the Wolf type, but differs from other vessels of its class in that it has not a complete iron hull, only the frame and deck beams being of iron, while the planking is of wood and yellow metal. No copper is used on the bottom. The "composite system" of building is looked upon with favor for ships of this kind, because iron vessels which are kept permanently at stations in the tropics soon become overgrown in spite of good care, and thus suffer a great loss of speed. In a wooden vessel the crew's quarters are better and more healthful than in iron vessels, for they are not as much affected by the temperature outside of the ship.

The greatest length of the Eber is about 245 ft.; its breadth, 26 ft.; its depth, 14 ft.; and it has a displacement of about 500 tons. The armament will consist of three long 5 in. guns in center pivot carriages, and a small number of revolvers. One of the former will be placed at the stern on the quarter deck, and the two others on the forecastle. Some of the revolvers will be on the quarter deck and some on the forecastle, care being taken to arrange the guns so as to obtain the widest possible range, thus enabling the ship to protect itself perfectly.

The Eber is provided with a two-cylinder, compound engine, which can generate 650 horse power, giving the vessel a speed of 11½ knots. The coal bunkers are so large that the ship can travel 3,000 miles at a speed slightly less than that just mentioned without requiring a fresh supply of coal. The rigging is the same as in iron vessels of the Wolf class, and the sails are sufficiently large to allow the vessel to proceed without steam. The ship will carry about 90 men, including officers, crew, engineers, and firemen.

A sum of $145,000 was appropriated for the construction and equipment of the Eber, which was begun at Kiel in the latter part of 1885, and was launched February 15, 1887.--_Illustrirte Zeitung_.

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NEW BRITISH TORPEDO EXPERIMENTS.

The torpedo experiments against the Resistance, which have been suspended since November last, were resumed on June 9 at Portsmouth by the officers of the Vernon. The injuries received by the ironclad in the previous experiments having been repaired, so as to make the vessel watertight, the old ship was towed up the harbor, and moored in Fareham Creek. Our readers are aware that the Resistance is an obsolete ironclad which has finished her career as a battle ship, and that nothing could have converted her into a modern armorclad.

Although it was intended to render the experiments final and conclusive as a practical demonstration under service conditions of the destructive effects of the Whitehead torpedo when directed against a modern vessel of war, the results still leave behind them much uncertainty. The Resistance was built of iron, whereas battle ships are now exclusively constructed of steel, and it would be perhaps hazardous to state that the behavior of the two metals under a sudden and violent shock would be exactly the same. The construction of the double bottom of the old ship is also different. Since the last experiments were carried out against her, however, measures have been taken to make her as far as possible the counterpart, so far as under water arrangements and coal protection are concerned, of a modern ship of war.

At the last attack, the Whitehead was directed against the after part of the hull on the port side in wake of the boilers. During the present series of experiments the old ship was assailed on the same side, but directly amidships, in the neighborhood of the engine room. As no steam was got up in the boilers, the effect of the jar upon the steam pipes, glands, and feed connections remains a matter of speculation. So far as the consequences of the burst upon the structure of the hull itself is concerned, every care was taken to make the ordeal as complete and instructive as possible. The wing passage, which has a maximum diameter of 3 ft. diminishing to a point, was left empty, although at the former experiments the lower portions were filled with coal. But behind this, and at a distance of 8 ft. from the bulkhead, a longitudinal or fore and aft steel bulkhead 3/8 in. thick had been worked to a length of 61 ft., and, with the coal with which the intervening compartment was packed, formed (as in recent armorclads) a solid rampart, 20 ft. high, for the defense of the engine room.

The height of the double bottom between the outer and inner skin plating is 2½ ft. The watertight compartments were divided into stations by means of vertical lightening plates pierced by three holes, and in order to make them, as far as was practicable, resemble the bracket frames of a modern armorclad, the center of the plates was cut away so as to leave a single oval hole instead of the three circular holes. In view of the differences of opinion which exist on the part of experts on the subject of under water protection, the officers of the Vernon had determined to submit the problem to the test of experiment. For this purpose steel armor 1½ in. thick had been worked along the outside of the upper skin of the double bottom throughout one of the compartments, in addition to the other protection mentioned. The Resistance had been brought down by iron ballast to a trim of 25 feet 9 in. aft and 19 ft. 7 in. forward, giving a mean draught of 22 feet 8 inches. She was consequently rather further down by the stern than before, but was in other respects the same.

When in commission, the Resistance had a mean draught of 26 feet 10 inches. The present series of experiments was of even greater importance than the first series. The attack was gradually developed by means of fixed and outrigger charges of increasing power, and the _coup de grace_ was not given by means of a service Whitehead in actual contact until various lessons had been derived.

The opening experiment on June 9 consisted of an attack directed against a new system of torpedo defenses which are to be carried by ships in action, or when in expectation of an attack, rather than an assault upon the ship herself. The previous experiments had clearly demonstrated that a Whitehead, when projected against a vessel at close range, and consequently with a maximum of motive force, could not get through the ordinary wire netting before expending its explosive energy in the air, and that the spars by which the nets are boomed out from the ship's side could be reduced to 25 ft. in length without danger to the hull. The ordinary wooden booms employed on board ship, however, are heavy and unwieldy, weighing, as they do, more than half a ton each. In ordinary circumstances, the spars cannot be lowered into place and the nets made taut in less than a couple of hours, and the work of stowing them is equally slow and laborious.

Mr. Bullivant, who manufactures the torpedo netting and hawsers for the navy, has devised a method of getting rid of the difficulties complained of by substituting steel booms for the wooden booms and an arrangement of pulleys and runners, whereby the protection can be run out and in, topped and brailed up out of the way, with great facility. The system was tried at Portsmouth last year with considerable success upon the Dido, but as it was thought that some of the fittings were somewhat frail and might collapse beneath the shock of a live torpedo, it was resolved to submit them to a practical test under service conditions upon the Resistance. The ship was consequently fitted with three of the steel booms on the port side. They were 32 ft. long and spaced 45 ft. apart, and connected by a jackstay to which the nets were attached. Each steel boom weighed 5 cwt., or less than half the weight of the ordinary boom, and whereas the latter is fixed to the ship's side by a hook which is liable to be disconnected or broken by the jerk of an exploding torpedo, Mr. Bullivant's boom works in a universal or socket joint, which cannot get out of gear except by fracture, and which permits the boom to be moved in any direction, whether vertically or fore and aft, close in against the sides. Below each boom is a flange, which serves as a line along which a traveler moves, the latter being actuated by means of a topping line running over a pulley at the head and another near the heel.

Upon the booms being topped to a perpendicular position, the nets are attached to the runners at the bottom of the booms close inboard (instead of, under the existing system, to the tops of the booms from boats alongside or otherwise), and when this is done, the mere depression of the booms into position will cause the nets to run out of their own accord. In like manner, when the occasion for their use has passed, the raising of the boom will cause the nets to come alongside, when they can either be brailed up through the grummets or disconnected for future use.

The action of the gear is so simple and rapid that the torpedo protection can be always ready without arresting the way of the ship. As a length of net 30 ft. by 20 ft. deep weighs about 3 cwt., it will also be seen that the reduction of strains by working the crinolines from the heel instead of the head of the booms is considerable. The attack by the Whitehead upon the booms and nettings was made shortly before 2 p.m., at the time of high tide.

The whole affair occupied a very few minutes. As soon as the red pennant was struck on board to show that Mr. Bullivant was satisfied with the arrangements, and that the target was ready, the torpedo vessel Vesuvius got under way, and after circling round the doomed hulk discharged a Whitehead against the netting from her under-water bow torpedo tube at an approximate range of 50 yards. As on former occasions, the missile was one of the old 16 inch pattern, but it was understood that the charge of gun cotton had been reduced to 87 lb., so that the net protection should not bear a greater strain than would be the case in actual hostilities. The torpedo, which was set to a depth of about 10 feet, struck the net in the middle and threw up an immense spout of water, but without getting to the ship, which was apparently uninjured. Although it hit the net immediately below the center boom, no fracture occurred, and the points remained intact. Although at the short range the torpedo would spin through the water at from 30 to 40 horse power, and would deliver a formidable blow upon the net, the thrust was effectually resisted, though as a matter of course the net was much torn by the explosion of the baffled projectile.

Although at the second torpedo attack made on the Resistance, the following day, the offensive power that was brought to bear was quite exceptional, the victory remained with the ship. The charge exploded was an exceptionally heavy one. It consisted of 220 lb. of gun cotton. It was consequently more destructive than any which is ever likely to be launched against an armorclad much better prepared to resist it than the obsolete and time-worn Resistance. An idea, however, had got abroad that the Russians either have or intend to have a locomotive torpedo capable of carrying the same weight of explosive in its head, and the object of the experiment was to ascertain what would be the effect of the detonation of such an enormous charge upon the submerged portions of a ship of war.

But, while this was no doubt the primary purpose in view, the experiment also served the secondary purpose of determining the result of the explosion upon the net defenses of a ship. Mr. Bullivant's booms and runners, which were found to be scarcely anything the worse from the ordeal of the previous day, were again used. The damaged net was taken away and one of the old service grummet nets slung in its place, the cylinders containing the gun cotton being attached to the jackstay immediately in front of the battered sides, and 30 feet from the hulk, and sunk to a distance of 20 feet below the water line, which would bring it about opposite the bend of the bilge. By 3 p.m. everything was ready for the explosion of the charge--everybody had cleared out of the ship while the surrounding small craft drew off to a distance of 300 feet. The charge was electrically fired from a pinnace. The burst was terrific and the reverberation was heard and the shock distinctly felt in the dockyard. But the remarkable thing was that the hulk did not appear to jump in the least, though there was not more than six feet of water under her keel. That she would not be seriously crippled by the discharge seems to have been accepted as a foregone conclusion by Captain Long and the other torpedoists, as the day for the third experiment had been fixed in advance; but that the steel booms with their double flange running ways, stays, travelers, and hinges should have resisted the tremendous jar and upheaval was a genuine surprise for all concerned, and goes far to prove that except a vessel be taken unawares, it will be impossible for a torpedo to come into actual contact with it. At the experiments last year the wooden booms were unhinged and splintered under a much less violent shock. But the steel booms employed, though somewhat bent, remained unbroken and in position, and the joints were quite uninjured. All that is necessary for perfect defense is that the booms should be made a little heavier.

The torpedo experiments against the Resistance were resumed on June 13, when the old ironclad suffered some rough treatment. As the experiment was understood to be the last of the second series, and was fully expected to have a sensational termination, a considerable number of interested spectators were attracted to the scene in Fareham Creek. The torpedoists resorted to severe measures, but with a distinctly useful purpose in view, having bound the ship hand and foot, so to speak, in such a way that her name became a solecism. They exploded 95 lb. of gun cotton 20 ft. below the water, and in contact with her double bottom. This amount of explosive represents the full charge of the old pattern 16 in. Whiteheads; but as the hulk was, for prudential reasons, moored close to a mud bank, and as the water was consequently much too shallow to allow of a locomotive torpedo being set to run at the required depth, a fixed charge was lashed fore and aft against the bottom plating of the ship and electrically exploded from No. 95 torpedo boat.

In previous experiments this year the ironclad was attacked on the port side, which had been specially strengthened for the occasion, and the result was a victory for the defense. On June 13 the starboard side was selected for attack, in order that a comparison might be instituted with the effects produced under different conditions by a similar experiment.

Last year in the latter case the double bottom was filled with coal; and after the charge, which was lashed against the ship in the same way, had been exploded, it was found that the bilge keel had been shivered for a length of 20 ft., while the lower plating had been much bulged above the bilge keel. Four strakes of the skin plating extending up to the armor shelf had also been forced inward and fractured where they crossed the longitudinal frames. They had parted in the middle for a distance of 8 ft., while some of the butts had been opened so that gashes 2 in. or 3 in. wide appeared between them. The coal had been pulverized and scattered in all directions, and other internal damage inflicted. Nevertheless, the watertight bulkheads remained intact, and by confining the influx of water to a single compartment so much buoyancy was preserved that, though the ship heeled over to starboard and was maimed, she remained afloat, and might have continued to fight her guns, provided always that no injury had been sustained by her machinery, a point which these experiments do not touch. Crippled, however, as she was, it was thought at the time (and the probability was strengthened by subsequent examination of the ship in dock) that the coal, instead of being a protection to the double bottom, had in reality proved a source of weakness by receiving the energy of the explosion from the outer plating and communicating it to the inner plating, and so distributing it throughout the submerged portions of the hulk.

The question was sufficiently important to demand an experimental solution; hence the _raison d'etre_ of the present demonstration. The double bottom, which is about 2½ ft. deep, was consequently kept empty, and the torpedo placed in immediate contact with it in such a manner that, being overhung by the contour of the hull, the ship would feel the full force of the upward as well as the lateral energy of the charge. On other accounts the importance of the experiment was obvious, for, although it had been ascertained that torpedo nets were capable of protecting a battle ship from the bursts of the heaviest locomotive and outrigger charges, it might happen, of course, that the nets would be rent or displaced by shell fire or swept away by a grazing ram or even attacked by a double torpedo, the second passing through the gashes made by the explosion of the first in any case. It was, therefore, of urgent necessity that the effect of a torpedo bursting in immediate contact with a ship's bottom should be practically and clearly determined. The charge on June 13 was fired just before 5 p.m. in the wake of the boilers, and it was soon perceived that something of a fatal character had taken place from the appearance of coal dust sweeping up through the hold. The report had not the dull boom to which the spectators had become accustomed. Instead of this, the gun cotton exploded with a sharp, angry, whistling noise, while the manner in which the mud was churned up showed that the force of the rebound was terrific. The ship lifted bodily near the stern, after which it was seen to leisurely heel over to starboard some eight or ten degrees, and finally repose, though not until the tide fell, upon the mud. The old hulk had been mortally wounded at last.