THE HOTCHKISS REVOLVING CANNON THE HOTCHKISS REVOLTING CANNON. A DESCEIPTION OF THE SYSTEM. ITS EMPLOYMENT IN THE FIELD, IN FORTIFICATIONS, ETC. AND FOE NAVAL SERVICE. WITH TABLES GIVING RESULTS OBTAINED IN EXPERIMENTS MADE WITH IT. BY ALFRED KOERNER. WITH FIFTEEN PLATES. PARIS: PRINTED FOR PRIVATE CIRCULATION. 1879. [ ll rights reserved. ] PARIS PRINTING OFFICE OF T SYMOXDS RUE ROCHECHOUART CONTENTS. Page Preface .............. 7 Introductory Historical Note on the Hotchkiss Eeyolying Cannon . . . . 9 CHAPTEE I. The Gun. � General Description of the System. � Construction in Detail.�(a) The Group of Barrels, (b) The Frame, (c) The Breech, (d) The Mechanism.� Operation of the Mechanism. � Peculiar and Distinct Characteristics of the Mechanism.�List of Parts composing the Eeyolying Cannon.�Directions for Dismounting and Ee-assembling the Eeyolying Cannon . . . . .11 CHAPTEE II. The Ammunition.�The Common Shell.�Steel Shot.� Canister Shot.�The Metallic Cartridge-Case.�Hotchkiss Percussion Fuze.�Desmarest Fuze . . . .18 CHAPTEE III. The Eeyolying Cannon for Field Service, for Fortifications, etc.�Its Constructive Peculiarities, Ballistical Features, etc�Principal Weights and Dimensions.�Field Carriage for Eeyolying Cannon.�The Limber.� The Ammunition-Waggon.� Principal Weights and Dimensions of Carriage, Limber and Ammunition-Waggon. �Eanges of 37mm Eeyolying Cannon (Light and Heayy Models).�Bursting of the Projectiles.�Directions for Working the Eeyolying Cannon in Field or similar Service. ............. 23 CHAPTEE IV. Eesults obtained in Experiments made with the Eeyolying Cannon.�Eesults of Firing at Sandy Hook, U.S.A.�Comparison of the Eesults of Hotchkiss Eeyolying Cannon with those obtained from other guns.�Conclusions.� General Eemarks on the System .............. 32 6 CHAPTER V. Note on the Tactical use of the Revolving Cannon.�1. For Field Servicer Against Infantry. 2. Against Cavalry. 3. Against Artillery.�4 Attack and Defence of Fortified Positions.�5. Coast Defence.�6. Diverse Purposes.�Conclusions . 40 CHAPTER VI. The Light 37mm Revolving Cannon for Naval Service.�Description and Special Constructive Features.�Principal "Weights and Dimensions of Gun and Ammunition. �Range, Deflection, Deviation, etc.�Penetrative Effects of the Projectiles against different objects.�Table of Perforative Effect of Shell.�Accuracy of Fire in Service Afloat against rapidly-moving objects. � Comparison of the Rapidity of Fire of the Revolving Cannon with that of Mitrailleuses . 45 CHAPTER VII. Revolving Cannon for certain particular purposes.�HotchMss Mitrailleuse.�The 40ram Gun for Flanking the Ditches of Modern Fortifications.�The 47mm Revolving Cannon for Naval Service.�The 53ram Revolving Cannon . . , . .55 List of Plates.............60 PREFACE. Machine-guns, in some form ol" other, have become of late years an integral part of the armaments of most nations. The disappointment, however, which was experienced during the Franco-German war of 1870-71 as to the value of the class of machine-guns generally known as mitrailleuses, i,en rapid firing guns, which discharge small bullets or mi-traille, has brought this weapon in disrepute, and more particularly so as their use has been entirely or partially abandoned by some Nations who have had the most experience with them. The nature of this kind of arm has led to a multitude of more or less ingenious and complicated mechanical inventions, in which the ballis-tical features have often been totally disregarded. This, of course, is partly the reason why mitrailleuses are looked upon with disfavour by many military authorities. There is, however, no reason to doubt but that a mitrailleuse is an arm considerably inferior to a cannon; for field service it is an impediment, for naval service it is useless against the lightest protection which is carried by launches, or torpedo-boats; and for the use in boats, which are in constant motion, no accuracy can be got out of it. The aforesaid considerations point out the necessity of an arm of greater power and having the indispensable advantages of explosive-shell fire. The Hotchkiss Revolving Cannon, which is herein described, represents a machine-gun combining to the best extent the requirements of both field and naval service. It is not exactly a new invention, as it was first brought out in 1871; since then it has been subjected to exhaustive trials and the severest tests by several governments, and its adoption into the French service, as well as that of several other countries, has confirmed the ideas of its inventor, and has made it an object of much interest. The Revolving Cannon may now be considered as a complete and thoroughly developed system, and a practical weapon for service. 8 A small pamphlet describing this gun was published in 1874 ; but in a work of this nature, devoted to a subject which is in course of continual improvements and developement, the data requires to be constantly corrected and extensive additions made thereto, so that a frequent revision becomes necessary. A part of the before-mentioned pamphlet has been embodied into the present book,, but it can scarcely be called a new edition of the former. The author hopes that this description of the Hotchkiss system may be of some interest to military and naval authorities, as this arm certainly deserves their serious consideration, and will doubtless bear its full share in the determination of future wars. A. K. Paris, March, 1879. THE HOTCMISS REVOLVING CANNON INTRODUCTORY HISTORICAL NOTE ON THE HOTCHKISS REVOLVING CANNON. It was during the Franco-German war, *in 1870-71, that Mr. B. B. Hotchkiss, on seeing the inefficiency of the French mitrailleuse, first conceived the idea of constructing a simple machine-gun, able to produce a continuous hail of small cast-iron explosive shells at very long ranges, and which should have no recoil to interfere with the continual operation of the gun or the accuracy of its fire. Besides the well-recognised cases in which machine-guns may be employed with great advantage, this gun should be adapted for the attack of troops in loose order, and must therefore permit of easy and rapid adjustment, so as to be able to readily follow all minor movements of the enemy. It was in the same year that the first gun of this kind, made at Vienna, was fired in the presence of the Austrian Artillery Committee ; and though it was thereby proved to be excellent as to general principle, it left much to be desired from a ballistical point of view. In addition to some of these guns being purchased as samples by the Russian and Italian Governments, a battery of them was ordered by the French "Government of National Defense;" but the delivery could not be completed in time for them to be used during the war.- In 1872 further experiments were made at Vienna, after the mechanism of the gun had been so far improved that the loading could be performed automatically, which was hitherto not the case. The following year was spent by the inventor in improving the gun, both mechanically and ballistically, and not until the summer of 1873 were any but private experimental trials made. 2 10 In July, 1873, the French Marine Department, wishing to thoroughly test the qualities of this arm, ordered trials to be made with it at Gavre ; and the Minister of Marine, after the results of this trial, in order to assist the inventor in augmenting the power of his arm, courteously caused a series of experiments to be made to test the value of the different improvements which had been introduced in consequence of the experiences at this trial in July, 1873. The results afterwards obtained thoroughly confirmed the expectations which were placed in the efficacy of the arm, but for the moment no steps were taken to introduce it into the service. In 1875 the Revolving Cannon was adopted for service in the Brazilian Army, and in the same year a torpedo vessel, of the Argentine Navy, was armed with them; subsequently these guns have been purchased by the Chinese, United States and Qther governments. In 1876 the French Navy required a gun specially adapted for the protection of their ships against torpedo attacks, to repulse boarders, and for boat service. The French, or Montigny mitrailleuse and the Gatling gun,�already in their posession,�-as also the Palmkrantz mitrailleuse, were not found suitable for the purpose, and Mr. Hotchkiss was entrusted by the Director of Naval Artillery with the construction of a gun based upon the principle of his Revolving Cannon. After very extensive and practical trials, the Hotchkiss Revolving Cannon (naval model) was adopted for the armament of ships and boats, and in 1877 and 1878 several hundred of these guns were ordered by the French Navy at the Hotchkiss Ordnance Works. The adoption of this gun into the French Navy was soon followed by Turkey, Holland and Greece, and other governments have ordered guns for trial. CHAPTER I. THE GUN. GENEKAL DESCRIPTION OF THE SYSTEM.�CONSTRUCTION IN DETAIL (a). THE GEOUP OF BARRELS (b). THE FRAME (c). THE BREECH (d). THE MECHANISM.�OPERATION OF THE MECHANISM.-PECULIAR AND DISTINCT CHARACTERISTICS OF THE MECHANISM.-LIST OF PARTS COMPOSING THE REVOLVING CANNON.�DIRECTIONS FOR DISMOUNTING AND RE-ASSEMBLING THE REVOLVING CANNON. GENERAL DESCRIPTION OF THE SYSTEM. The Hotchkiss Revolving Cannon cannot be classed with mitrailleuses in the ordinary sense of the term, as explosive shells are fired with the former, and it has a range equal to that of modern field artillery. The Revolving Cannon is a compound machine-gun, in which it has been sought to combine the advantages of long range shell-fire, with the rapidity of action of the mitrailleuse, to produce therefore the powerful effects of artillery fire with a gun having no recoil and other valuable features of the mitrailleuse. The gun consists of five barrels, grouped around a common axis, which are revolved in front of a solid immovable breech-block. This has in one part an opening to introduce the cartridges, and another opening through which to extract the empty shells, whilst the cartridges are discharged singly, as they present themselves by the rotary motion to the blow of the firing-pin, and while motionless in front of the solid portion of the breech. The turning of a crank causes the automatic loading, firing and extraction of the empty cartridge-cases, all these operations being performed continuously during the movement of the crank. The obturation is caused by the metallic cartridge. 12 ' Different models of the Revolving Cannon have been constructed, each to suit the special requirements of the services for which they are employed. These types vary only in their ballistical features, in weight, dimensions and in the manner in which they are mounted. The general system and arrangement of the mechanism being common to all calibres. CONSTRUCTION IN DETAIL. (See plate 1.) The Revolving Cannon is composed of four distinct parts, viz.:� (a) The group of barrels. (b) The frame, carrying the trunnions and serving as a bearing for the forward-end of the central-shaft. (c) The breech, containing the mechanism. (d) The mechanism. (a) The group of barrels is composed of five rifled guns A A, made of Whitworth's fluid-compressed steel. They are rigidly mounted, parallel to each other, around a central shaft J9, between two gun-metal disks G and G\ The group of barrels rests in the frame E carrying the trunnions. The frame is attached to the breech D by means of four screws ee, the rear end of the shaft B penetrating the same to receive the rotary motion of the driving gear. The barrels are revolved and controlled, as well as the mechanism for loading, firing and extracting by means of a hand-crank f, placed on the right side of the breech. (b) The frame E is of gun-metal, and is composed of two � shaped longitudinal beams carrying the trunnions ; it is connected at the forward end by a cross-piece, to give the bearing for the central shaft B of the group of barrels ; the rear end of the frame forms the rest for the breech-block, which is carried by, and fastened to, the longitudinal beams. (c) The breech itself is of cast-iron, massive at its face, to receive the concussion of the discharge ; it is comparatively heavy, and absorbs the greater part of the recoil. The hollow rear portion, containing the mechanism, is closed by a door 6?, which can be opened by turning the button d1, so that the mechanism is freely accessible, and can, if necessary, be dis- 13 mounted and replaced in a few moments without the aid of any tools whatsoever. (d) The mechanism for rotating the barrels, and performing automatically the functions of loading, firing and extracting, is composed of the crank-shaft F^ carrying a worm ZZ", which works in a pin-wheel b on the rotating axis of the barrels. The worm i7is curved in a peculiar manner, partly helical and partly circumferential, thus imparting an intermittant rotating motion to the group of barrels, whilst the worm is rotated continually. The combination of the mechanism is so arranged that the loading, firing and extracting take place during the time the barrels remain stationary. The worm H carries at its right side a cam G, shaped to a logarithmic-spiral. The arm n, of the firing-pin N, bears against this cam, and is by the rotation retracted, and allowed to fly forward at the proper time under the action of the spring 0, and so strikes the primer and discharges the cartridge. The manner of rotating the barrels and discharging the cartridge explained, there now remains to describe the arrangements for loading and extracting; this is effected in the following manner :� On the interior face of the left side of the breech, a cog-wheel m is mounted, with two horizontal racks L1 and M1 running in slides. The rack M1, which is attached to the loading-piston M, is placed above, the other Ll carrying the extractor, under the cog-wheel and parallel to the axis of the barrels, so that in moving one of these racks the other is moved by the cog-wheel m in the opposite direction. Part of the lower rack forms a curved link, or yoke, in which a small crank 7, on the crank-shaft f, works. The rotation of the latter consequently imparts an alternating and opposite movement to the two racks, so that while the one is going forward the other moves back, and reciprocally, thus a fired cartridge-case is extracted whilst a loaded cartridge is being introduced into the barrel above. The cartridge is not " driven home " entirely, but it is in view of an helical-ramp i?, cut into the metal of the breech, on which it slides when it is moved by the rotation of the barrels. This completes the introduction of the cartridge into its chamber, gradually and without shock. "When the racks L1 and Ml are in the extreme positions, they remain 14 stationary a moment, whilst the barrels are still revolving. This stop, or lost motion, is obtained by giving the slot above and below the centre a circular shape, corresponding to the throw of the crank L This is necessary to cause the head of the cartridge-case to engage in the hooks of the extractor, and to provide time for the new cartridge to enter the introduction-trough. The extractor proper L consists of two grooved lugs at the end of the rack L\ into which the head of the cartridge is engaged by the rotation of the barrels. After the cartridge is withdrawn from the barrel, it strikes against an ejector, which pushes it out of the extractor, and it falls to the ground through an opening in the under part of the breech. The extractor not depending on any spring to retain its hold on the cartridge, is positive in its action. To obviate the difficulties which exist in other systems of machine-guns, when the cartridges are piled one upon the other, the introduction-trough, or receiver, in which the loading-piston M works, is closed by a hinged gate P, which swings down by the weight of the cartridges, the first of which enters the receiver, and the loading-piston in moving forward rises the gate and isolates the other cartridges from the one in the act of being pushed into the barrel. In this manner airjamming of the cartridges in rapid firing is obviated. To facilitate the loading of the Revolving 'Cannon, a detachable feed-trough B is fitted to the receiver, into which a number of cartridges can be fed at a time; they are from this automatically distributed to the barrels by the action of the mechanism and fired. In view of obviating stiffness in the working of the gun from rust and dirt, gun-metal has been used for those parts of the mechanism which are subjected to sliding motion, as well as for the frame, the discs which carry the barrels and the door for closing the rear of the breech, and for some minor parts. 15 THE OPERATION OF THE MECHANISM. The operation of the mechanism may be described as follows, supposing the crank to be in continual motion :�� A cartridge is placed in the feed-trough Q, the feed-gate P descends and allows it to enter the receiver ; the loading-piston M pushes it into the barrel, then the barrels begin to revolve, making at each movement one-fifth turn, and the cartridge is carried on until it arrives at the lowest position and comes before the firing-pin JV, which penetrates the solid part of the breech, and which has in the'meantime been retracted by the action of the cam G. As soon as the cartridge has arrived in this position, the barrels cease to revolve, and the primer of the cartridge is struck by the firing-pin and discharged ; then the barrels make another fifth turn, and the fired cartridge-case is carried on until it comes to the extractor L, this in the meantime has arrived up to the barrels, and the cartridge-head rolls into it. As soon has the head is laid hold of by the extractor, the barrels again cease to revolve, and during this period the cartridge-case is withdrawn and dropped to the ground. As during every stoppage of the barrels the gun is supplied with a new cartridge, and the firing and extraction is performed during this time, a continuous but slow fire is kept up. By supplying the gun in this manner with single cartridges, about forty rounds per minute may be fired. Should rapid firing be required, the gun is then not supplied with single cartridges, but with "feed-cases/7 containing groups of ten cartridges each, and in this manner from sixty to eighty rounds per minute can be fired, either in volleys or continuous fire, as desired. The feed-cases open automatically by the action of inserting the same into the feed-trough. To recapitulate the manner of operation :�The supply of cartridges is regulated by the feed-gate P; the barrels are loaded by means of the loading-piston M\ the intermittant rotating motion imparted to the group of barrels by the worm H\ the cartridges are fired by the firing-pin iV, this in turn being operated by the cam G ; and, lastly, the fired cartridge-cases are withdrawn by means of the extractor Z, which is actuated by the crank 7, the movement to the whole mechanism being imparted by turning the hand-crank f. 16 PECULIAR AND DISTINCT CHARACTERISTICS OE THE HOTCHKISS MECHANISM. 1. Intermittant rotation of the barrels, without rotation of the breech or mechanism. 2. The barrels remaining stationary at the moment of discharge, the loading and extraction also taking place during this stop, thus suppressing the tangential motion with which the projectiles of such guns are animated at the commencement of flight, which have continuous rotating barrels, at the same time suppressing any chance of accident from a " hang-fire" cartridge, as the barrels remain a relatively long time in their firing position. 3. The employment of but one single loading-piston, one firing-pin and spring for all the barrels, thus giving great simplicity to the mechanism, and allowing at the same time all parts to be made sufficiently strong and heavy to sustain the rough usage to which a gun is subjected in actual service. 4. The shock of discharge is received against a massive immovable breech of considerable weight, which distributes it to the whole system. This permits the employment of charges and projectiles only limited by the weight and dimensions thought proper for the gun and carriage, to suit the different requirements of the service for which it is to be employed. 5. The mechanism of the gun being disposed in such manner that no tools are necessary for dismounting or re-assembling the same. LIST OF PARTS COMPRISING THE REVOLVING CANNON. 1. Group of barrels. 2. Frame with the trunnions. 3. Breech-block containing the mechanism. The mechanism of the gun is composed of the following eleven parts :� 4. The hand-crank, with which the whole mechanism is operated. 5. The crank-shaft, carrying the worm and the extractor-crank. 6. The worm, giving intermittant rotation to the barrels, at the same time carrying the cam which operates the firing-pin. 7. The extractor-crank, imparting the movement to the extractor, and thus, by means of the action of the racks and cog-wheel, giving the reciprocating movement to the loading-piston. 8. The extractor. 17 9. The loading-piston. 10. The cog-wheel, for transmitting the movement of the extractor to the loading-piston. 11. The firing-pin. 12. The V-shaped firing-spring, with its fastening. 13. The feed-gate, for regulating the supply of cartridges. 14. The locking-screw, which fixes the extractor-crank on the crankshaft. DIRECTIONS FOR DISMOUNTING AND RE-ASSEMBLING THE REVOLVING CANNON. To dismount the mechanism :� 1. Open the breech-door 6?, by unscrewing the button cV. 2. Withdraw the firing-pin N. 3. Take out the locking-screw &, which fixes the extractor-crank to the crank-shaft. 4. Withdraw the crank-shaft F, by pulling the same towards you, then the worm iJis loose, and so are the extractor and the loading-piston. 5. Take out the worm H, and then withdraw the extractor L and the loading-piston M. The mechanism is re-assembled in the inverse manner. Care must be taken to push the loading-piston as far forward as possible before putting the extractor in place, so that the proper teeth will engage in the cogwheel m, which is fixed to the left side of the breech-block, and need not be dismounted. Should it be necessary in any particular case to take the gun entirely apart:�Begin by dismounting the mechanism as above described; then the pin-wheel b must first be taken off; this is screwed on the central-shaft B, and is held in exact position by a conical pin, driven through the pin-wheel and the shaft. In order to drive this pin out, it is necessary to remove the screw which closes the hole on the top of the breech-block ; then by inserting a punch into this hole the pin can be knocked out and the pin-wheel b unscrewed from the shaft; this removed, it is only necessary to take out the four screws e e . , which connect the frame with the breech, and the latter can then be withdrawn and the whole gun seperated. 3 CHAPTER II. THE AMMUNITION. THE COMMON SHELL. � STEEL SHOT. � CANISTER SHOT. � THE METALLIC CARTRIDGE-CASE.�HOTCHKISS PERCUSSION FUZE.�DESMAREST FUZE. (See plate 6.) The ammunition for the Revolving Cannon consists of a centre-fire metallic cartridge of special construction, holding in each one the powder, the projectile, and the percussion-primer, arranged in a similar manner to the ammunition generally used for small arms. Three different kinds of projectiles are used, viz. :� A. Common shell. B. Steel shot. C. Canister shot. A. COMMON SHELL. The shell is a brass-coated, hollow cast-iron projectile, which is forced through the polygrooved bore of such diameter that it can only receive it by the lands cutting their way into the soft guiding-band* The shell is cylindro-ogival in shape, slightly ogival at the near end; its length varies from two-and-a-half to three calibres, according to the model of gun. For field service it is generally fitted with the Hotchkiss percussion fuze. For naval service the Desmarest fuze is sometimes used. The coating which takes the rifling is a soft brass guiding-band of about one calibre in length, and placed symmetrically from the centre of gravity. 19 This coating is contracted over the projectile, which is provided with a number of grooves encircling the body under the band. The pressure de-velopped on the ignition of the charge moulds the coating into these grooves, so that it presents a cannalured surface before entering the rifling. This disposition reduces the strain and friction caused by forcing the projectile through the bore to a minimum. The coating of the projectile is conical at its front part, corresponding with the cone in the projectile chamber, so that it is exactly centred in the bore as soon as the forward motion commences, For bursting charge, dimensions, etc., see table, page 25. The projectiles are turned smooth all over, and are made with great care and exactness, with only a very small deviation in dimensions; they are painted with black lacquer. B. STEEL SHOT. The steel shot resembles the common shell very closely in exterior shape, the head is, for better penetration, brought up to a sharp point and is hardened in oil. The steel shot is cored; but no bursting charge is employed. The arrangement of the guiding-band is the same as that of the shell. Steel shot is generally only used for naval service, where great penetration is necessary. C. CANISTER SHOT. The case is made of tinned iron, the front end is closed by a conical zinc cup ; the base, on which rests a wrought-iron disc, consists of a lead cup cast to the body; its form causes it to be expanded by the force of the charge, and to thus close the windage. The balls are made of lead and antimony, and are packed in sawdust. Canister shot is seldom used for other than flanking purposes. THE CARTRIDGE-CASE. The cartridge-case consists of a slightly conical, spirally-rolled tube of 20 sheet-brass, strengthened at the base with an inside and an outside cup of the same material. The head is punched out of sheet-iron, and is fastened to the body with rivets. The primer consists of a brass case, holding the anvil, and is closed at the bottom end by a cap containing the fulminate ; it is fitted into a hole which penetrates the head and both cups, and it projects through into the inside of the cartridge-case. The cups are pushed up around the primer-cavity, so as to form a gas-check for the primer. The construction of the body of the cartridge allows it to expand to the chamber of the gun without tearing the metal; after the discharge it contracts itself again, thus leaving the fired case perfectly loose in the chamber for extraction. This cartridge has proved itself to be of a very durable quality, and it can be reloaded, after having gone through the process of cleansing, reforming and repriming, on the average, eight times. The projectile is pressed into the neck of the cartridge, and is then clenched at four points, this being enough to hold it absolutely secure. Of course, by the construction of the ammunition the powder charge is rendered safe against influences of weather and danger of explosion. THE HOTCHKISS PERCUSSION FUZE. This percussion fuze is generally used with the Revolving Cannon for field and naval service; it has been found to be perfectly safe, and withstands well the roughest usage and transport in the limbers. - It is of the double reaction system, requiring the concussion of the discharge to prepare it for work, and the sudden retarding of the projectile to cause it to act. It consists of a gun-metal case, closed at the front end with a screw-cap ; it has a conical hole at the rear, which is closed with a lead plug (the safety-plug), pressed in very tightly; the plug projects a little through the base of the body-case, towards the inside. The plunger, holding the detonating composition, is composed of lead, cast into a brass casing, to strengthen it and to prevent the lead being upset by the shock of discharge. Two brass wires, cast into the lead oji opposite 21 sides of the plunger, hold it suspended, the wires going through the hole in the bottom of the case, and they are arranged in such a manner as to prevent any independent rotation of the plunger during the flight of the projectile ; they serve at the same time to hold the plunger securely in position by means of the safety-plug, before the discharge. The plunger holds a detonating-cap, and in its axis it has a small chamber, filled with tightly-pressed powder, which takes a fraction of a second to burn, and thus allows the projectile to rise after it has struck on graze before the explosion takes place. The operation of the fuze is thus :�The safety-plug is dislodged backwards into the interior of the projectile by the shock of discharge; the wires then not being held tight in the hole, the plunger is disengaged, and rests on the bottom of the fuze-case, and is free to move in the line of axis. When the flight of the projectile is suddenly retarded by its striking any object, the plunger, in consequence of its inertia, is driven forward, and the primer strikes against the point of the screw-cap, thus igniting the powder in the channel, and so firing the bursting charge of the projectile. The Hotchkiss percussion fuze acts well on graze, as on direct impact; it requires no adj ustment before use; it is waterproof, and is perfectly safe during all manipulations of the projectile, as the plunger is held securely by the safety-plug, which must first receive the shock of the discharge to dislodge it from its hole, and thus liberate the plunger. THE DESMAREST PERCUSSION FUZE. This fuze has been adopted by the French Navy for the Revolving Cannon. It does not explode well on graze, but it has the advantage of being very simple in its construction. The body-case is made of gun-metal, and it has a cavity at the base, which holds the cap containing friction-primer composition. The plunger consists of a plunger of light wood, into which is screwed the roughened steel point, which serves to explode the capsule by friction. The wood plunger is pressed into the case tightly, and is then held securely in position by two brass suspending-wires, the mouth of the body is closed by putty to make it water-tight. 22 No preparation is necessary before using the fuze, which acts by direct impact in the following manner :�When the projectile strikes an object, the plunger is driven backwards by the shock, and the roughened point penetrates the cap and explodes the same. The wood plunger being very light, the concussion on the discharge of the gun does not move the same, it being also held by the suspending, wires; but premature explosions occur occasionally, nevertheless. CHAPTER III. THE DIFFERENT CALIBRES OF THE REVOLVING CANNON. � THE REVOLVING CANNON FOR FIELD SERVICE, FOR FORTIFICATIONS, ETC. ITS CONSTRUCTIVE PECULIARITIES, BALLISTICAL FEATURES, ETC. � PRINCIPAL WEIGHTS AND DIMENSIONS.�FIELD CARRIAGE FOR REVOLVING CANNON.�THE LIMBER.�THE AMMUNITION-WAGGON.�PRINCIPAL WEIGHTS AND DIMENSIONS OF CARRIAGE LIMBER AND AMMUNITION-WAGGON.�RANGES OF 37mm REVOLVING CANNON (LIGHT AND HEAVY MODELS).�BURSTING OF THE PROJECTILES.�DIRECTIONS FOR WORKING THE REVOLVING CANNON IN FIELD, OR SIMILAR SERVICE. THE DIFFERENT CALIBRES OF THE HOTCHKISS REVOLVING CANNON, THEIR PURPOSES, CONSTRUCTIVE PECULIARITIES AND BALLISTICAL FEATURES. At present six different models of the Revolving Cannon have been constructed, viz. :� 1. The light 37mm�gun of 225 kiL for field service, firing an explosive shell of 455gr' in weight, with an initial velocity of 402 met> per second. 2. The powerful 37mm gun, weighing 475 k% for field service and for flank defense, etc., firing an explosive shell of 525gr' with an initial velocity of 458 met> per second. 3. The 40 mm gun of 460kiL in weight, specially constructed for flanking ditches of modern fortifications. 4. The light 37 mm Revolving Cannon of 200kiL for naval service, firing an explosive shell of 455 g% with an initial velocity of 402 met' and a steel shot of 590 g% with an initial velocity of 353met> * In these pages the French measurements of length and weight are thus abbreviated:�" met." for metre ; "cm." for centimetre ; " mm." for millimetre ; " kil." for kilogramme ; "gr." for gramme. 24 This gun is mounted on a swivel, and is trained and fired from the shoulder by.one man. 5. The 47 mm naval gun of 550 k\ Weight of explosive shell, 1,100 ki\ Initial velocity, 425 met. Weight of steel cored-shot, 1,100 M1. This gun is similar in construction to the light naval model; it is also mounted on a swivel, and is trained and fired from the shoulder by one man. 6. The 53 mm Revolving Cannon of 1100 ld\ Weight of explosive shell, 1,800 ki\ Initial velocity, 450 met. REVOLVING CANNON FOR FIELD SERVICE, FOR FORTRESSES, ETC. (See plates 1, 2 and 3 J The Revolving Cannon was designed to serve as a powerful auxiliary to the modern field systems, as well as for employment in fortresses, siege-works, etc. Its capacity for delivering a deadly, incessant and widespread shell fire at all field-ranges; its superior rapidity, total absence of recoil, abolishing all bat the initial pointings, give it, for many special purposes, decided advantages over ordinary field cannon. The necessity of suppressing the recoil and still conserving a good initial velocity of the projectile, with the weight generally admitted for a gun for field service, has made it necessary to limit the weight of the projectile to about 525gr', and consequently to adopt the calibre of 37 mm. With a charge of 110gr of French Ripault ordinary cannon powder, the projectile attains an initial velocity of 458met" per second and a maximum range of about 5000 met- The carriage is provided with a lateral training-apparatus, as well as with the ordinary elevating-screw, so that it is possible to point the gun in elevation and in direction without moving the trail of the carriage. The gunner can thus rectify his fire, during the operation of the gun, by observing the explosions of the falling projectiles. Lately, a lighter model of the Revolving Cannon has been constructed for field service, as the question of mobility is of vital importance, and for bad roads the powerful model is often found too heavy. 25 The calibre of this light gun is also 37mm, but the weight of the gun has been reduced to 225kil*. To still be without recoil it was necessary to reduce the charge and the weight of the projectile. The latter weighs 455gr*.� The charge is 80gr', giving an initial velocity of 402 met' with French Ripault powder, and a maximum range of about 4500 met-%% The carriage and limber, and the other material also, have been considerably reduced in weight, and the track of the wheels is narrower. Four horses, or mules, are sufficient for the transport. PRINCIPAL DIMENSIONS AND WEIGHTS OF THE REVOLVING CANNON FOR FIELD SERVICE. A. GUN, Weight of Kevotving Cannon Barrels of Whitworth's fluid-compressed steel. Helicoidal rifling. i Total length of gun . Preponderance at the breech Number Calibre Length .... Weight of each barrel . Number of grooves . Depth of grooves (uniform) Width of lands (uniform). Pitch of rifling, one turn in Twist .... Light 37mm model. OOK kil. 6&V 5 orj mm 740 mm U ML 12 0.4 mm O mm 1107 mm left hand . 1180 mm 15kil- . Heavy 37mm model. 475 ML 5 orj mm 1276 mm 36 ML 10 0.4 mm o mm 1250 mm right hand 1990 mm 30 kiL B. AMMUNITION Total weight of projectile ..... Weight of bursting charge .... Entire length of projectile ..... Weight of metallic cartridge-case Charge of powder ...... Total weight of complete cartridge . Total length of complete cartridge Initial velocity of projectile .... * This is above the weight allowed by the St. Petersburgh Convention for explosive bullets. ** The same charge (80gr) of- Curtis & Harvey's E.F.G.2 powder gives an initial velocity of 435met, and necessarily a slight increase of range.- 455gr . .. 525 gr 22gr . .. 25 gr 93 mm . . Illmm 95gr . .. 110 gr 80 gr . .. 110 gr 630gr . .. 750 gr 167 mm . . 206mm 402 met . . 458met 26 FIELD CARRIAGE FOR THE REVOLVING CANNON. (See plates 1, 2 and 3.) For this gun a special steel and iron carriage has been constructed. This was found necessary, as the ordinary field gun-carriage is not provided with the means for procuring an excellent and immovable rest for the gun. The trail of the carriage is formed of two bracket sides, connected together by two transoms and bolts, and the gun-metal rest for carrying the trunnion-saddle, the rear end being connected by the trail eye-piece, made of cast-steel, to prevent wear on the limber-hook. The brackets diverge against the trunnions. The axle-tree is made of tough steel. The wheels have metallic naves and ring-tires. This carriage has a traversing arrangement capable of giving 4deg* deflection to the gun ; it consists of a cast-steel saddle, with trunnion bearings, and works in the gun-metal rest riveted to the brackets. The elevating and traversing arrangement consists of a steel ball-and-socket elevating-screw, which allows the breech of the gun to move freely in any direction. The elevating-screw works in an oscillating bearing ; this bearing, or nut, and with it the elevating-screw, can be traversed right and left by means of a small hand-wheel on the left side of the trail, and this causes the trunnion-saddle with the gun to pivot around the centre of the saddle. On the right side of the trail there is a compressing-handle to lock the elevating-screw, so as to make it immovable during fire, and whilst travelling. The handspike, of iron tubing, is hinged to the trail so as to fold back for travelling. A tool-box is placed between the trail, this at the same time makes another solid connection of the trail-brackets. To suppress the recoil of the gun, and to take out all vibrations from the slack of the wheel-hubs on the axles, etc., a brake of the following description is used :� Each axle-arm has a screw cut on its extremity, this carries a nut forming a conical cap, partly enveloping the back side of the wheel nave, which is likewise conical, to fit the inside of the cap; this has a crank by which it can be revolved on the axle. When screwed up, this cap grips the cone of the nave of the wheel, and the tighter the cap is screwed up so the wheel turns with more difficulty on its axiSj until it gets immovably 27 locked on the axle by the friction of the cones. When the cap is unscrewed it is disengaged from the wheel, which then can turn freely on the axle. The screws on the ends of the axle-arms have right and left-handed threads, so that the caps become tightened by the effect of the recoil. This break is used at the same time as an ordinary travelling-brake, and it can be applied without the carriage being stopped, as is necessary with the shoe-brake, commonly used on gun-carriages. The carriage of the Revolving Cannon is sometimes provided with a light steel shield for the protection of the gunners from small-arms fire. This shield is of three parts, made to fold together, thus forming seats for two men. It can immediately, when coming into action, be unfolded, and only the muzzles of the barrels and the wheels of the carriage are exposed to the enemy. The steel plates are 5mm in thickness and proof against the fire of any existing military rifle, should even two bullets strike on the same spot. The carriage carries the following implements, namely :�A sponge on the right bracket and two handspikes beneath the trail. The tool-box contains:�The feed trough, hand-crank, rear sight, screwdriver, oil-can, reserve spring, reserve firing-pin, hammer, pin-driver, universal wrench, etc. THE LIMBER. (Seeplate 2) The steel and iron limber is formed of four futchells�the outside ones of flat steel, the inside futchells and the splinter-bar being of angle-iron�a platform-board and footboard of oak. The axle-tree is of hollow wrought-iron; the wheels and track are the same as for the gun-carriage. The futchells and splinter-bar are all riveted together, and the cast-steel limber-hook is riveted-in between the inside futchells, the axle-tree is secured to the bed by three bearings, and the whole forms together a solid framework. The limber has swing splinter-bars of steel, to which the traces of the horses are attached, and the shaft is arranged for double draught. The swingle-tree is also of steel. The limber carries an ammunition-chest made of steel-plate, conveying three hundred rounds of ammunition, one hundred of which are packed in ten galvanised steel "feed-cases" ready for rapid firing. 28 The limber carries the following implements, namely :�Set of entrenching tools and axe, water-bucket, traction-rope, cushions for seats on ammunition-chest, etc. The inside of the ammunition-chest is also fitted for carrying grease-tin and divers small tools. THE AMMUNITION-WAGGON. The ammunition-waggon consists of the waggon limber�with steel-plate ammunition-chest�identical with the gun limber; and the rear-waggon, conveying two ammunition-chests similar to those of the limber. It is constructed entirely of steel and iron, and is fitted with brakes similar to those of the carriage. There are two foot-boards, and arrangements for carrying spare wheel, entrenching tools, spare pole, swingle-trees, and other accessories. PRINCIPAL WEIGHTS AND DIMENSIONS OF CARRIAGE, LIMBER AND AMMUNITION-WAGGON. CAEEIAGE AND LIMBEE. Extreme angles of elevation and depression Greatest angle of dispersion with horizontal training apparatus Weight of carriage with tools and accessories , Weight of limber (empty) ....... Weight of limber charged with 300 rounds .... Track of wheels ......... Diameter of wheels . . . . . . Total weight of gun, carriage and limber, charged with 800 rounds ammunition and all accessories ...... AMMUNITION-WAGGON. Waggon limber, identical with carriage limber Eear-waggon with two ammunition-chests Track and diameter of wheels same as carriage Weight of ammunition-waggon (empty) . . . . . 650 Total weight of ammunition-waggon, charged with 1200 rounds of ammunition and all accessories......1400 Light 37mm model. .-5 + 18degr- 4 deg . 250M-270 mi. . 460 M1-1200 mm . 1150mm of 1400k Heavy 37mm " model. -5 + 20 deg-4 deg> . 450 kiL . 415kiL . 640 kiL . 1600 mm . 1400 mm . 2050kil- 1100 ML 2050 kil 29 The weight of 1400m for the light 37mm gun, with its carriage, limber and outfit, distributed over four horses, gives 344^ per horse. The weight of the heavy 37Imn gun, etc., 2050kil*, distributed over six horses, gives 342kn* per horse, so that both guns possess the quality of easy transportability to a satisfactory extent. RANGES OF 37mm CALIBRE REVOLVING CANNON (light AND HEAVY MODEL). Weight of Pkojectile. Initial Velocity. Light 37ram Model. Heavy 37nim Model. 455 gr. 402 met. 525 gr. 458 met. Angle of Elevation. 3� 5� 10" 15" 20� 25" 30" 35" Range in met. 1199 1614 2616 30?8 3526 4123 4360 4473 Eange in met. 1240 1723 2842 3460 3916 4240 4580 4700 BURSTING OF THE PROJECTILES. Twelve projectiles of 525^' weight, and charged with 25gr> of musket powder, were burst in a box filled with wet sand, so that nearly all the fragments were obtained after the explosion. (See plate 7\) The average number of fragments from each projectile were eighteen of iron, three of the brass band, and the fuze, comprising :� Two pieces weighing between 80 ^ and 50^ Nine � � � 50 � 25 Eleven � � under 25 It will be seen that the bursting is very regular, and the weight of the fragments as good as can be desired for a gun of this class. 30 DIRECTIONS FOR WORKING THE REVOLVING CANNON IN FIELD OR SIMILAR SERVICE. The number of men for service with each gun should be six, although four can serve the piece in case of necessity. The first gunner on the right flank works the crank, and also gives the rough pointing by means of the handspike. First gunner on the left flank lays the piece, and regulates the fire by means of the elevating and traversing screws. Two second gunners relieve each other in feeding the gun with cartridges. They each carry a cartridge-pouch holding ten cartridges, around their waist, and besides this a feed-case for rapid fire, which is charged with ten rounds, and is suspended from the shoulder, under the left arm, in a small pocket.0 The two third gunners, at the limber, fill the feed-cases and hand them to the second gunners. After the gun is unlimbered, it is roughly laid by means of the handspike. The traversing apparatus should be set in its centre position, which is indicated by a point corresponding to a mark on the transom immediately behind the elevating screw. Then the wheels should be clamped by means of the wheel-brakes, the levers of which must be turned down tight by pressing on them with the foot, then the exact sighting in elevation and direction is done by means of the elevating and traversing screws. After this the hand-crank and the feed-trough are mounted, and the gun is ready for loading. At the command u Load " the second gunner puts a feed-case containing ten cartridges in the feed-trough (supposing the loading to be done by means of feed-cases). The case opens automatically, and the cartridges roll into the feed-trough, and are ready to be fed into the barrels the moment the command " Fire " is given. At the command "Fire" the first gunner on the right flank turns the crank, and at each complete revolution of the same one round will be discharged, so that it takes ten turns of the crank to fire the ten rounds. * it is sometimes preferred to do all the loading by means of the feed-cases, as greater rapidity can be attained in this manner. 31 After having discharged the ten rounds, and the gun is in proper position to continue fire, the feed-case is withdrawn, and another one is inserted into the feed-trough, and so forth. If a continuous and rapid fire is required, the feed-cases are inserted into the feed-trough in rapid succession by the two second gunners. In this manner the fire can be kept up any length of time required, without intermission, at the rate of from sixty to eighty rounds per minute, and the projectiles can be distributed over a sector of 4deg', by working the traversing-wheel, without moving the trail of the carriage. As the gun is entirely without recoil, the sighting can be regulated during the fire by observing the explosions of the falling projectiles, and no time is lost in finding the elevation when the enemy changes its position rapidly as long as it is within range of the projectiles. If some cartridges are left in the gun after " Cease fire" has been ordered, they can be extracted, without discharging them, by opening the breech-door ; this door being open, the spring does not act on the firing-pin, and this therefore does not strike the primer, but the extractor withdraws the loaded cartridge in the same manner as it does the fired cartridge-case. To limber-up the gun it is first necessary to unscrew the recoil-brakes. This is done by running the carriage a few inches forward, the brakes then unscrew automatically, and by lifting back the tightening levers, the wheels become entirely loose on the axle for travelling. CHAPTER IV. RESULTS OBTAINED IN EXPERIMENTS MADE WITH THE REVOLVING CANNON.� RESULTS OF FIRING AT SANDY HOOK, U.S.A.�COMPARISON OF THE RESULTS OF HOTCHKISS REVOLVING CANNON WITH THOSE OBTAINED FROM OTHER GUNS.�CONCLUSIONS.�GENERAL REMARKS ON THE SYSTEM. RESULTS OF FIRING WITH HOTCHKISS REVOLVING CANNON (field model of 1874) AT SANDY HOOK, U.S.A., SEPT. 11, 1876, TO FEB. 15, 1877.* Mean observed velocities of the projectiles at 30m6t- from muzzle of gun. Weight Charge Kind Velocity of of of at Projectile, Powder. Powder. 30 met, 520gr nogr- New mortar. - 394,4 99 >> Musket. 479,1 " >? Old mortar. 445,4 EAPIDITY OF FIRE. Nov. 23, 1876. Jan. 25, 1877. 20 rounds fired in 14J seconds 51 40 10 48 33 71 ' 2 Mean rapidity of fire 70 rounds per minute. * See Annual Report of the Chief of Ordnance to the Secretary of War, U.S.A., for the fiscal year ending June 30, 1877. Washington, 1877. 33 ACCUEACY, AND EFFECT OF FIRE, AGAINST TARGETS AT DIFFERENT RANGES. Results at 183 metres (200 yards). Targets A and B. {Seeplates 10 and 11.) A. Ten targets 15m.et* long, l,8met- high, placed 15met> apart. Distance of first target from gun, 180met-; of last target, 318me\ 102 rounds fired, giving 2140 hits. The destructive effects are apparent. The fire was directed on to the front target, and executed in two groups ; the direction of gun being slightly changed for the second group. B. Two targets 15,6met- long, 3,3met' high, placed 22,5met- apart. Distance, of first target from gun, 183me\ 100 rounds fired, giving 1045 hits. The fire was so directed that the shells burst a little in front of the targets, so that the fragments might ricochet on to the same. Results at 915 metres (1000 yards). Targets A and B. {See plates 12 and 13.) A. Four targets 7,8met< long, 3,3met> high, placed 18met' apart. Distance, of first target, from gun, 915 me\ 143 rounds fired, giving 1285 hits. B. Ten targets 15met* long, l,8met- high, placed 15met' apart. Distance of first target from gun, 915 met. 112 rounds fired, giving 1626 hits. Results at 1830 metres (2000 yards). {See plate 14.) Four targets 7,8met long, 3,3met' high, placed 18met" apart. Distance of first target from gun, 1830me\ 170 rounds fired, giving 963 hits. The "U.S. Ordnance Board say, in the before-cited report, with regard to these results :� ....." As the rapidity of fire is about 70 rounds per minute, an analysis shows that at a range of 1000 yards a continuous and dangerous fire (about 590 hits per minute in the first series A) can be secured. In the series B, firing at 10 targets, representing a regiment in columns, 100 shells were used; 1626 hits were noted. This gives a continuous and dangerous fire of 1800 hits per minute, and using only 52 M1 of metal�results not yet attained in any other machine-gun, nor with our present field artillery. The range of 915 mefc-(1000 yards) is one too long for accurate effects, generally, from the lighter calibre of other machine systems, fired eyen with great deliberation. 5 34 The targets made at the distance of 1830 mefc' (2000 yards) were accomplished by firing 170 rounds, and the total number of hits was 963, giving a continuous and dangerous fire at this range of 370 hits per minute. " Any comparison at this distance (1830 met-) ceases with other machine-guns ; and we have to consider the system at this range, as a competitor of field cannon. " No direct comparisons have been as yet made by the Board between the Hotchkiss Revolving Cannon and the ordinary field-pieces, but it is thought well to allude in this connection to the more recent practice with the most approved field artillery. The recent experiments in Austria* are probably the best so far made, and will afford us a fair comparison. This comparison will be incomplete, but this incompleteness will favour the field artillery rather than the Hotchkiss system. "The records alluded to show that 40 shells, ' with double walls/ weighing in the aggregate, say 254kiL, gave 1497 hits on targets placed at 1500 met* (1658 yards). The time required for accurate firing could not have been less than ten minutes. This amount of metal, if delivered from the Hotchkiss Revolving Cannon, would, if a ratio following from the results already quoted is accepted, give 2000 hits and at a distance of 1830 met- and in a time of seven minutes. " Comparison cannot be made at maximum ranges (3660 met-) reported by the Austrian artillery, as no records are yet made at this distance with the Revolving Cannon. The Revolving Cannon which served in these experiments was covered with a tarpauling, and was left out on the beach at Sandy Hook until November, 1878, when some new experiments were carried out with it, and although the gun was very rusty and had become much clogged with sand and dirt, it required nothing else but oiling to render it fit for work, and the series of trials were carried out with the gun in the state it was found, after being exposed to the influence of the weather for nearly a year. COMPARISON OF THE RESULTS OF HOTCHKISS REVOLVING CANNON WITH THOSE OBTAINED FROM OTHER GUNS. A part of the trials made by the French Navy at Gavre, in July, 1873,** comprised some practice with a Revolving Cannon under exactly the same conditions as with four Gatling guns of different calibres, which had shortly before been under experiment by the same commission, with a view of comparing the effects of these different kinds of arms. * See " Mittheilungen tiber Gegenstande des Artillerie und Genie-Wesens," VI Jahrgang, Wien, 1875. ** See " Memorial de l'artillerie de la marine," 2e livraison, Paris, 1874. 35 The Gatling gun, which is admitted to be one of the best mitrailleuses ; a comparison of the results of the Revolving Cannon with that system will be of some interest. The guns under test were as follows :� Natube op Arm. Weight of Projectile. Charge. Bursting Charge. Weight of Gun. 37mm Revolving Cannon . . . 25,5� Gatling Gun...... 16 6mm 1 I mm Hmm Mountain Gatling . . . gr. 490,00 256,85 97,52 24,20 24,20 gr. 85,00 31,77 19,33 5,16 5,16 gr. 20,00 kil. j 475 347 335 170 64 1 met. Fiest Experiment : Firing against a battalion of infantry in columns divided into three troops or companies, represented by 3 targets, each 1,8' high, and 70met long, placed at distances 70met" apart. Distance of all guns from the first target, 1650 m*\ TABLE I. d ition Number of Hits. � r-4 >d 1 Nature of Arm. levation. a 0 Ammun Ll. jrofHit of Hits. 3� 8.1 CO � Power. o o rget rget. rget. a tage Hit tion 1 . Angle Number Expenditu 1st Ta 2nd Ta 3rd Ta Total N Percer Number of Ammuni Effec 6�36' 80 53,6 3 39 13 55 70 1,04 36,40 8�25' 400 15,7 24 2 45 45 11,25 2,85 26,32 llmm Mountain Gatling... 10�15' 435 17,1 10 0 16 16 3,70 0,89 8,62 The superiority of the Revolving Cannon is here well marked. Second Experiment : Firing against a battalion of infantry in columns, divided into peletons, represented by 6 targets, each 1,8met" high, and 35mefc< long, placed 35met' distance apart. Distance of all guns from first target, 1795 met< 36 TABLE II. Nature of Arm. Angle of Elevation. 1 Number of Rounds fired. Expenditure of Ammunition | in kil. 1 Number of Hits. Total Number of Hits. Percentage of Hits. Number of Hits per kil. of Ammunition expended. 1st Target. 2nd Target. 3rd Target. 4th Target. 5th Target. 6th Target. Revolving Cannon .. 25,5mm Gatling Gun. 16,6mm Gatling Gun. 6�30' 6�1' 6�14' 80 300 216 53,6 113,4 36,5 2 12 3 49 76 6 42 66 6 25 12 20 20 3 5 1 3 1 139 172 40 173,7 44,1 18,9 2,59 1,45 0,90 90,32 33,82 31,49 In this case, also, the Eevolving Cannon in results much surpasses the Gatling gun. CONCLUSIONS FROM THE FOEEGOINC. In comparing the results obtained in Table I, we find that the number of hits per 100 shots fired with the Eevolving Cannon, during an equal length of time, are six times greater than those obtained with the llmm Catling Cun, and twenty times greater than with the llmm Mountain Catling. The number of hits per kil. of expended ammunition is less for the Eevolving Cannon than for the Field Catling, but more than for the Mountain Catling, while the effective power * is :� For the Revolving Cannon . . . . . . 36,40 For the Field Gatling.......26,32 For the Mountain Gatling......8,62 * By the effective power of an arm is understood the compound quantity which is governed by the number of hits on the targets, the time of firing, the distance the targets are placed from the gun, and the dimensions of these targets. In the determination of the effective power, there are, besides the unit of time, two quantities, which are fixed by the conditions of the practice, viz., the range and the dimensions of the targets, and as these are chosen analogically to the circumstances under which the arms to be tested are subjected in actual service, we have the means of comparing different kinds of arms1 under the practical conditions they are employed in. Observe that the effective power under the above stated conditions affords no judgment of the weight of ammunition expended, and as there are certain cases, where it is not only important to know what effect can be produced with an arm, but what quantity of ammunition it requires to produce this effect, it is necessary to compare these two figures with each other, and we can thus form a true judgment of the merits of the different arms. 37 In Table II. the percentage of hits of the Eevolving Cannon is four times higher than of the 25,5mm Gratling, and nine times higher than that of the 16,6mm Gatling, and the number of hits per kil. of expended ammunition is nearly double of those obtained with the 16,6 ^ Gratling. The effective powers are :� For the Bevolying Cannon ...... 90,32 For the 25,5mm Gatling.......33,82 For the 16,6mm Gatling ,.....31,49 That is to say, in this case the Revolving Cannon obtained an effect three times as destructive as the Gatling guns, with an expenditure of half the weight of ammunition. Too much importance should not be attached to these comparative results, on account of the small number of shots fired, and the limited kinds of application, yet it must be admitted that the great accuracy and range, combined with the quantity of projectiles which can be fired in an equal unit of time, makes the Revolving Cannon a very superior weapon. It must also be remarked that these results were obtained with a gun of the first model, built in 1871, of inferior ballistical capacity, with a projectile weighing 490gr' and a charge of 85gr" Since this time the inventor has augmented the power of his arm, so that there is reason to expect from the guns of most recent date, using a projectile of 525gl% and a charge of 110g% some results much superior to those obtained in 1873, and it is to be regretted that sufficient data for making a comparison of the effects obtained with the latest models does not exist. The superiority of the Revolving Cannon over mitrailleuses becomes the more remarkable the greater the distance at which it is used ; whilst at ranges up to 250 or 300met, and for purposes of flank defence, etc., canister-shot, also, can be used with success. GENERAL REMARKS ON THE SYSTEM. On thus examining the results obtained by the Revolving Cannon, it is found to be an arm of very superior capacity and of well-calculated proportions. The power of the powder is utilised in a high degree, for, with a projectile weighing 525gr> and with a charge of about one-fifth, there results an 38 initial velocity of 458met and a range of about 5000met'; an effect which only recently has been obtained with regular field artillery, whilst the precision of the fire, in both range and direction, is remarkable, and will bear comparison with the most approved systems of field artillery. The trajectory of the gun is, for its effective range, low, and a very precise, rapid, and effective fire can be kept up at distances up to 3000 m<% corresponding with an angle of elevation of 12deg' This machine-gun has, besides its great accuracy and range, the peculiar and valuable advantage of firing explosive shells, producing the greatest moral and physical damage to the enemy, and enabling at the same time to rectify its fire by observing the explosions of falling projectiles, thus giving it an incontestable superiority over all other machine-guns and mitrailleuses. As there is no recoil and no change of direction during the fire, the gun, once laid, will continue to throw from sixty to eighty explosive shells� representing in weight from 30 to 40kil* of cast-iron�per minute, at ranges approaching to those of field artillery. This is about three times the amount of work which can be performed by the most recent and perfect systems of ordinary field-pieces. As each shell of the Revolving Cannon gives, in the mean, on bursting, ten fragments between 40 and 80gr" in weight, besides twelve smaller fragments, which are also capable of doing considerable damage to men and horses, this gun is capable of delivering a continuous fire at the rapidity of at least 60 shells per minute, giving 60 dangerous zones of explosion and divided into a hail of about 1300 fragments of sufficent power to put men, horses and materiel hors de combat If we imagine the action of a battery of these guns, during a decisive moment of an engagement, and take the rapidity of fire at only 60 rounds per minute (a figure which can be considerably surpassed), the six guns would discharge about 190ki1, of iron, consisting of 360 explosive shells and producing 7900 dangerous fragments per minute, and this very destructive fire can be brought to bear with great accuracy on objects within the effective range of over 3000met'; it even conserves much of its power up to the maximum range of 5000met' The projectiles ricochet up to about 3000met* The essential mechanical arrangement of the system is simple and compact ; the working parts are strong and of simple form, and they are all 39 encased within the solid breech, and not one of them is exposed to the shock of discharge. The brass coating of the projectiles affords an excellent bearing for the grooves of the rifling, and at the same time obviates the difficulties of leading and fouling of the bore, while the circular grooves, cut into the body under the band, reduce the friction to the smallest possible extent, thus giving a satisfactory velocity with a minimum of strain on the gun. The metallic cartridge always produces an absolutely gas-tight closure of the breech. Another feature of this arm, to be well estimated in actual service, is its facility of manipulation. The operation of loading is simple, and the gunners only require the briefest instruction, and it is almost impossible, by the roughest usage and ignorance of the construction, to derange the mechanism, or to disturb the proper working of the gun. The traversing apparatus on the carriage enables the gun to be pointed in a horizontal direction as well as in elevation, without moving the trail of the carriage, and the projectiles can thus be distributed, during the fire, over a sector of a circle within its range, by adjusting the traverse. The gun has no movement during fire, its relative weight to that of the projectile/combined with the wheel-brakes, being sufficient to resist the recoil of each discharge. The simplicity, strength and durability of its mechanism better qualify the Revolving Cannon for actual service than other machine-guns, or mitrailleuses, hitherto constructed. CHAPTER V. NOTE ON THE TACTICAL USE OF THE KEVOLVING CANNON.�FOR FIELD SERVICE. 1. AGAINST INFANTRY. 2. AGAINST CAVALRY. 3. AGAINST ARTILLERY.�ATTACK AND DEFENCE OF FORTIFIED POSITIONS.�COAST DEFENCE.�DIVERSES PURPOSES. �CONCLUSIONS. NOTE ON THE TACTICAL USE OF THE HOTCHKISS REVOLVING CANNON (for field service). 1st. Against Infantry.�The Revolving Cannon may act with powerful effect against troops within 2000met' range, which comprises the distances within which the different groups of the infantry batallions of the first line are generally engaged, the different fractions of this force would then be in the most efficacious zone of action of these guns, and it is difficult to conceive how these fractions, even when profiting by all the favourable circumstances of the formation of the terrain, could manoeuvre and properly maintain their connections under a well-conducted fire of the Revolving Cannon. It would appear from the preceding that the Revolving Cannon may really have the advantage over ordinary field guns whenever there arises the necessity of concentrating a rapid and deadly fire against a given point, so as to produce very powerful effects, during a short period of time. It is of course evident that these considerations do not apply to cases when the troops are well covered by resisting obstacles, against which only heavier calibres can produce efficient effect. When acting defensively, the Revolving Cannon batteries should, after having performed their-work during the first period of an engagement, withdraw to the rear, to previously chosen points, so as to be able, if possible, to flank the principal line of defence, and to rake the approaches to the position. 41 Earthworks, against musketry fire, should be rapidly thrown up in front of the guns ; this will permit them to hold their position until the last, when they can be withdrawn from position and replaced in battery to meet the critical moment of an assault. If they can hold out until the assault takes place, they should, when the infantry has arrived within about 300met>, open a lively fire with canister; this would cover the front of attack with about 7000 balls per minute, and per battery. Under such conditions the success of an assault by the enemy would be very improbable. 2nd. Against Cavalry.�That which has been said concerning the mode of action of the Revolving Cannon against infantry will evidently apply to its use against cavalry, in any such case in which they might have the audacity to expose themselves to its fire. 3rd. Against Artillery.�The Franco-German war of 1870-71 demonstrated the inefficiency of the mitrailleuse against field artillery. This inefficiency had several causes, of which the following are the most prominent :� (a) The want of sufficient precision, and tension of trajectory, at long ranges. (b) The impossibility of regulating the fire by observation of the falling projectiles. (c) Lastly, the nature of the projectiles (bullets), which were only effective against men and horses, but totally powerless against materiel. The question is quite different with the Revolving Cannon. Its projectiles are powerful enough to damage field guns and their carriages�which are to-day very complicated and delicate machines�to blow up ammunition-chests, smash wheels, etc. In the point of facility and rapidity of laying the gun, and finding the range, the Revolving Cannon has an incontestable superiority over field cannon ; and though the dangerous zone of its traj ectory is of less extent than that of the larger calibre field-pieces, the total sum of the dangerous zones swept by its projectiles during a given time, will be considerably greater than the space swept by the field-piece during the same period of time. The enemy's guns would run greater risk of being obliged to suspend fire through loss of gunners, as the men would be quickly swept away by the rapid and severe fire of the Revolving Cannon, even at ranges up to 3000me\ 6 42 Suppose the two different guns in presence of each other, at a range between 1500 and 2000met>�that is to say, in the ordinary conditions of an artillery engagement. The fire of the Revolving Cannon, rapidly regulated, as before mentioned, would run at the rate of 40 to 50 rounds per minute, and the 700 to 800 fragments be directed against the enemy's materiel, their men and horses. This would not leave their gunners an instant quiet, and the incessant arrival of projectiles and the storm of fragments from the explosions would hardly allow them the coolness necessary to serve and properly point their guns. On the other hand, the field-piece would only be able to direct 2 rounds of shell per minute, against the Revolving Cannon and its materiel, giving from 80 to 100 fragments. In opening a shrapnel fire, specially directed against men and horses, the field-piece could discharge three shrapnels in two minutes, giving about 340 balls and dangerous fragments per minute. It would be extremely difficult to keep up a fire of this intensity if the enemy were exposed to the fire of the Revolving Cannon, and therefore the above figures could hardly be attained with field-pieces. En resume, the Revolving Cannon is able to discharge about 27M1, of metal, consisting of 50 shells, and furnishing 800 fragments, during the same unit of time that the most perfect field-piece could discharge 14kiL of metal, consisting�according to the employment of shell or shrapnel�of 2 or 1^ projectiles, furnishing in the first case 100, in the second case 340 dangerous fragments. Under these conditions it may be supposed that a battery of Revolving Cannon, well commanded and served, could hold its position on the battlefield with advantage, at the greatest distances at which artillery engagements are conducted, against a battery of ordinary field guns, and the Hotchkiss Revolving Cannon therefore certainly appears to merit a serious study as to its application for field service. ATTACK AND DEFENCE OF FORTIFIED POSITIONS. Attack.�For the attack and defence of fortified positions the Revolving Cannon appears also capable of rendering important services. The attacking 43 force may employ it advantageously to keep up a plunging fire at long ranges, which would prove very troublesome if directed against the places d'armes, roads of communication and assembling points of the garrison. The gun once directed is subject to no movement�either from recoil or other reasons �which might derange its direction, so that the fire can be interrupted and resumed at irregular intervals, and can be carried on without difficulty during night as well as day ; in this manner the defending forces would be harassed without intermission. During a bombardment, the batteries armed with Revolving Cannon should direct a slow but incessant fire against such centres of the attacked place, where fire has broken out, and thus prevent the approach of assistance, so as to allow the conflagration to spread with the desired rapidity. The Revolving Cannon could be well employed for the armament of batteries to prevent a sortie, to rake the faces of certain works, etc. Of course, it must be borne in mind that in the different above-stated cases the Revolving Cannon will act particularly against the personnel, for its projectile is not sufficiently powerful to be destructive against the materiel de place. Defence.�The Revolving Cannon, can be employed to cover the enemy's works with shell, particularly whilst establishing the batteries of the first period and at the moment of opening the trenches. Later some of these engines might be brought into position to be used for close attack; their incessant fire, directed at the head of the trenches, would make it very difficult and perilous for the enemy to advance. The projectiles of the Revolving Cannon are sufficiently powerful to destroy the gabionage by their explosion. It is a very suitable weapon for arming the counter-approaches, destined to rake the trenches and parallels of the enemy. Lastly, the Revolving Cannon, arranged specially for canister-fire, constitutes an excellent gun for flanking the long ditches of modern fortifications, as it is capable of sweeping the same by a storm of 1400 to 1500 balls per minute. This application of the gun has been experimented in the most thorough manner by the French artillery in the new forts of Paris. 44 COAST DEFENCE. Flying batteries, organised to protect certain parts of the coast�to prevent landing of troops, or a sudden attack on accessible parts of a coast line�cannot be armed with any system of gun so appropriate as the Revolving Cannon, for the effects of its rapid shell-fire against boats, and troops entirely without cover, landing on the shore, would be of the most deadly character and much superior to the fire of ordinary field cannon. DIVERSE PURPOSES. The Revolving Cannon constitutes a very valuable weapon for arming railway waggons, protected by light steel shields against small-arm fire, such as were used by the French in the Franco-German war of 1870-71. For the defence of bridges, passes, villages, etc.; it has always advantages over the mitrailleuse, as its explosive shell enables the effect produced to be seen and the laying of the weapon altered if necessary. CONCLUSIONS. The aforesaid suggestions and considerations will suffice to call attention to the services which the Hotchkiss Revolving Cannon can render in field artillery work. The experiments already made by different governments and those which are in course of execution appear to confirm the ideas of the inventor in that respect. It should be remembered that the great advantages of the Revolving Cannon become particularly apparent when the fire is carried on under conditions, approaching as much as possible to those of regular service on the battle-field�that is to say, when the targets are placed at unknown distances, the piece harnessed and run up to action in any accidental position, and nothing else being designated but the object, or target, to be acted against. It would be of much interest to compare the results obtained under such circumstances by the Revolving Cannon with those of ordinary field-pieces and the mitrailleuse. CHAPTER VI. THE LIGHT 37mm KEVOLVING CANNON FOE NAVAL SEKVICE. � DESCRIPTION AND SPECIAL CONSTRUCTIVE FEATURES.�PRINCIPAL WEIGHTS AND DIMENSIONS OF GUN AND AMMUNITION�RANGE, DEFLECTION, DEVIATION, ETC.�PENETRATIVE EFFECTS OF THE PROJECTILES AGAINST DIFFERENT OBJECTS.�TABLE OF PERFORATIVE EFFECTS OF SHELL. � ACCURACY OF FIRE IN SERVICE AFLOAT AGAINST RAPIDLY-MOVING OBJECTS.�COMPARISON OF THE RAPIDITY OF FIRE OF THE REVOLVING CANNON WITH THAT OF MITRAILLEUSES. THE LIGHT 37^ REVOLVING CANNON FOR NAVAL SERVICE. (See plates 4 and 5.) The light 37mm gun was specially designed for service afloat, to aid in the defence of vessels against the attack of torpedo-boats and boarders, mounted in the tops to cover the deck of an enemy's vessel with a hail of small explosive shells, to prevent the crews working the guns mounted en harhette, and to create disorder on board, for the armament of boats, further to protect a landing of troops, etc. Besides absence of recoil and rapidity of fire, it has been found necessary to have arrangements by which it should be made possible for one and the same man to hold and fire the gun, and to lay it for each round, in order to be able to efficiently repulse an attack of the rapidly-moving torpedo-boats. To attain this end the Revolving Cannon is mounted on a universal-forked pivot �7", the socket of which is fitted on the hand-rail, or any other convenient part of the vessel. A directing handle T is attached to the under part, at the rear of the breech. The gunner grasps this handle, whilst he bears the gun by means of a shoulder-piece 8 to his left shoulder, and 46 with his right he turns the crank f, which operates the mechanism ; during this time he keeps his eye constantly on the sights, and can thus direct the gun on any given object for each round he fires. To give sufficient steadiness to aim and fire at the same time, the hand-crank has been mounted at an oblique angle to the barrels, instead of turning in a plane parallel to the length of the gun, and its position is fixed in a manner that it may be rotated so far until the crank is close to, and can be stopped by the outstretched thumb of the left hand, whilst grasping the directing handle T under the breech. In this position the crank is near the firing-point, which is indicated by a point; the gunner then stops and takes aim, then, by a slight forward movement of the crank, he fires the gun. Two men are necessary to work the gun. One places the cartridges in the feed-trough, whilst the second with the shoulder-piece at his shoulder lays and fires. This arrangement enables the gunner to follow a moving object and to easily regulate his fire by observing the projectiles as they strike the object, or the surface of the water, although the distance and direction of the enemy may be varying very rapidly. For naval service " feed-cases " are not generally used, as volley firing is but seldom required. The cartridges are usually carried in a cartridge-pouch, holding twenty rounds, which is suspended by a belt around the shoulders of the man who feeds the gun. The gunner simply lays a cartridge in the feed-trough every time a shot is discharged, taking care to keep four to five cartridges continually in the feed-trough, so as to equalise any irregularity in the feeding of the gun. The pivot, in which the Revolving Cannon is held by its trunnions, is of gun-metal, and works in a gun-metal socket, in which it can rotate through an entire circle, so that the gun may be moved in a vertical, as well as in a horizontal plane, by the man handling the same. The trunnion-caps can be clamped, and so can the pivot be clamped in its socket, so that the gun can be fixed immovably, when not in use, by tightening the clamping-handles. These clamping-handles are not intended to be used when firing the gun, as it has been found absolutely necessary to have the same entirely mobile in every sense during action. The maximum rapidity of fire of this light naval gun is about 80 rounds per minute ; but in regular service, when exact sighting is necessary, so that 47 each shot may be effective, 30 to 35 rounds per minute may be regarded as the average, because the gun should be pointed for each round on observing the bursting of the previous shot fired; in this manner, when the range is great, the fire will be slow, but it will increase in rapidity as the enemy approaches, and when arrived near, rapid fire may be employed with advantage, but, of course, accuracy of fire should never be sacrificed for rapidity. For naval service a folding sight is used with the Kevolving Cannon. It is a bar which has a certain number of fixed sights, with the usual notch, corresponding to the elevations for ranges from 200 to 200met', and giving at the same time the permanent derivation, so that the gunner may pass rapidly from one range to another, without interrupting the fire, by simply moving his eye from one sight to the other. The front sight is a plain steel point, screwed into a collar which is fitted on the frame of the gun directly over the front disk of the barrels. The crank, the feed-trough and shoulder-piece can be dismounted and kept in the accessory-chest, which accompanies each gun. The door covering the introduction-trough is closed, and all is then made snug, when not in use. These are the essential modifications found necessary in order to render the Revolving Cannon practical for service afloat. It will be seen that these arrangements tend to make the gun sufficiently simple, light and well balanced, and to give it complete mobility in every sense. The addition of the shoulder-piece and directing-handle, and the sighting apparatus, make it possible for one and the same man to hold, sight and fire the gun with perfect ease, whilst it is being supplied with cartridges by a second gunner. PRINCIPAL WEIGHTS, DIMENSIONS, etc., OF THE 37mm NAVAL GUN AND ITS AMMUNITION. A. GUN. Weight of the Eevolving Cannon . . . . . . . . 200 Weight of pivot with its socket . . ' . . . . . . . 55 Barrels of / Number . . . . ...... 5 Whitworth's I Calibre......... 37 fluid-compressed j Length (20 calibres)........ 740 [ Weight of each barrel . . . . . . . 14= kil. kil. mm mm kil. 48 Number of grooves . Depth of grooves (uniform) Width of lands (uniform). Pitch of rifling (in calibres) Angle of rifling Preponderance at the breech Pressure of the shoulder-piece. Total length of gun (without the shoulder-piece) 12 Helicoidal rifling. Left-hand twist. B Total weight of shell Weight of bursting charge . Length of projectile Weight of metallic cartridge-case Charge of powder . Total weight of complete cartridge Total length of cartridge Initial velocity, with ordinary French Eipault cannon powder AMMUNITION. 0.4 mm 2 mm 29.9 6 deg. 15.2 Ml. 9.5 kil. 1180 mm 455 gr 22 gr 93 mm 95 gr 80 gr 630 gr 167 mm jnomet* RANGE, DEFLECTION, DEVIATION, ETC. EXPERIMENTS AT GAVRE (FRANCE), OCTOBRE, 1877. Weigt of projectile (common shell) . Charge of powder (ordinary French Eipault cannon) Initial velocity ...... Mean variation in velocity ..... Angle of relevement (positive).... 455 �* 80 gr 402 met 1,49 met A mln Elevation of gun. Number of rounds fired. Mean range. Mean deflection. Mean Deviation. Time of flight. Longitudinal Lateral. Degrees. 3 5 8 10 12 15 20 25 35 20 20 19 20 19 20 19 20 19 Metres. 1199 1614 2157 2615 2951 3028 3526 4123 4473 Metres. 6,2 to left 4,9 � 6,4 � 32.3 � 60,8 � 10.4 � 51,3 � 159,5 � 72,0 to right Metres. 14,8 14,8 18,34 21,5 21,1 33,7 32,2 31,9 55,3 Metres. 0,88 1,37 1,41 3,1 3,0 2,3 5,3 7,4 6,7 Seconds. 3,5 6,0 8,9 10,9 12,9 14,8 18,8 23,1 29,0 The charge of 80 sr of Curtis & Harvey's R.F.G.2 powder gives an initial velocity of 435met. 49 PENETRATIVE EFFECTS OF THE PROJECTILES OF THE 37mm NAvAL GUN AGAINST DIFFERENT OBJECTS. Experiments made at Gavre (France), in England and Austria, and at the Hotchkiss Ordnance Works, have shown that the shell of the light naval Revolving Cannon is capable of completely perforating the steel-plating of torpedo-vessels of the " Lightning " class, up to a range of 2500 met>, if striking nearly normally, and up to 2000 met* if they strike the vessel within an oblique angle of 30deg'. ( See plate 8 J The common shell will also perforate steel plates of 12mm thickness within a range of 500 me\ The Thorny croft steam torpedo-boats�even when running end on towards the gun, and the projectiles striking the vessel at an oblique angle up to 70deg' (see plate 9.)�are completely perforated by the fire of the Revolving Cannon within 500met> range. The projectiles will burst after having passed through, and fragments will damage the bulkheads and the machinery. Within a range of 700met' the steel shot will perforate the boiler, after having passed through the sides of a torpedo-vessel, if it strikes at any oblique angle up to 35 deg\ Maximum thickness of steel plate which can be perforated by the steel shot at 200met- range: 25mm. Experiments made at St. Petersburgh have demonstrated that within a range of 300 met" the common shell (without bursting charge) will pass through a steel torpedo-boat when coming end on, and will completely perforate three steel bulkheads of 2mm thickness each. The steel shot fired from the same gun, and at the same distance, passed through the bow of the torpedo-boat, then through three steel bulkheads, and lastly knocked a hole in the plate representing the boiler. The range-tables of the French Navy for the 37mm Revolving Cannon give the perforative effects of the shell in the following tabular form :� 7 50 PEEFORATIVE EFFECTS OF THE COMMON SHELL OF HOTCHKISS 37mm EEVOLVING CANNON AGAINST DIFFERENT TARGETS. Obliquity of Fire Distance up to which. I Natueb op Target. CD Remarks. to tlie Perforation Id Obstacle. takes place. mm degrees metres / Thornycroft \ ( � 3000 The shell, fitted with percussion 1 Torpedo- I 6 20 2800 fuze, bursts in passing through Tough 1 boats. ) ] Upper plating J I 30 2400 steel plates up to 15mm thickness I � 500 and through oak timbers up to Steel / of the frigate > 1 " Friedland." ) Plates. 1 15 20 400 30cm thickness, and projects dan- i 24 22 21 ( 30 0 ] 20 30 ) 250 point-blank gerous fragments behind these obstacles. range. Up to 1000met- range this shell, | \ fired at boards 25mm thick, bursts i / 100 o o o o CO CO 4000 in passing through or immediately i I 3800 800 after perforation. 1 300 400 Within ranges up to 1000met- the I 460 01 30 ) point-blank shell bursts on striking the water \ 400 range or on the first ricochet, Thickness of oak timber necess ary to stc >p the passa^ je of the shell fired at point-blank range . 70cm Penetration of the shell ii i oak t imber of 7 0cm thicknes 3 . . . . 53cm ACCURACY OF FIRE IN SERVICE AFLOAT, AND DIRECTED AGAINST RAPIDLY-MOVING OBJECTS, SUCH AS STEAM TORPEDO-VESSELS, ETC. Some of tlie most interesting experiments were made at Helder (Holland) in September, 1878, to determine the accuracy and rapidity of fire of the Revolving Cannon on board of vessel and when directed against fast steam torpedo-boats. The 37mm Revolving Cannon�light naval pattern�was mounted in the starboard bow of the iron-clad ram " Guinea." The target consisted of 51 a full-sized model of the steam torpedo-boats, built for the Dutch Government by Messrs. Thornycroft & Co. (See plate 15 J The torpedo-boat was anchored in the roads between Helder and the Island of Texel. The " Guinea'7 was under steam. In all the tests common explosive shell were used ; but only the direct through hits were counted, as it was supposed that hits from fragments of shells, which had burst on striking the water, would be powerless against the steel plates of the torpedo-boats. EXPERIMENTS ON SEPTEMBER 11, 1878. 1st. Expeeiment.�Sea calm. Force of wind 1-2. A strong current running. " Guinea" stopped at 600met< from torpedo-boat; boat taken nearly on broadside. 24 rounds fired in 1 min. 20 sec. 12 direct hits = 50 %. Besides this, the boat was struck by about 40 fragments of shell, which had burst on striking the water, before the target. 2nd. Experiment.�"Guinea" stopped at 600 met from torpedo-boat; projectiles striking at an angle of incidence of about 50^. 28 rounds fired in 1 min. 30 sec. 20 direct hits = 81i %. The target was hit also by numerous fragments. EXPERIMENTS ON SEPTEMBER 12, 1878. 3rd. Experiment.�Sea slight. Force of wind 3. " Guinea " steaming ten knots. Fire striking torpedo-boat at an angle of incidence of about 30deg-. Commenced fire when vessel had arrived within 800met' from boat, and continued until " cease fire" was ordered, when the " Guinea" had come nearly up to same. 46 rounds fired in 2 min. 30 sec. 28 direct hits = 61 %. 4th. Experiment.�Sea moderate. Force of wind 3. " Guinea " steaming twelve knots. Fire striking torpedo-boat at an angle of incidence of 52 about 45d9g\ Commenced fire at 1050met>; ceased fire at about 500met'from boat. 20 rounds fired in 1 min. 30 sec. 12 direct hits = 60 %. 5th. Experiment.�Sea rough. Force of wind 4. " Guinea" steaming ten knots and a-half. Fire striking torpedo-boat end on. Commenced fire at 1050met" and continued until nearly up to boat. 53 rounds fired in 3 min. 15 sec. 4L direct hits = 77 %. The hits from fragments were uncountable, and the boat was entirely riddled by fragments of the shells which burst inside and passed through the opposite side of the vessel. It will be remarked on examining the targets how well the shots can be grouped in the most vital part of the torpedo-boat, and to what advantage the greater mean deviation in range of the gun, to that in direction, can be utilised for covering the whole length of the same with projectiles, when she is running end on towards the gun. It was here demonstrated that it would be absolutely impossible for any torpedo-boat to approach a vessel armed with the Hotchkiss Revolving Cannon : she would be disabled or sunk as soon as she came in sight; and if a vessel is armed with several of these guns, as is the case, for instance, in the French Navy�of which some ships have as many as eight Revolving Gannon�it would be rashness for a whole fleet of torpedo-boats to continue the attack on such vessel, and they could be easily kept at sufficient distance that even the Whitehead torpedo, discharged from such boats, would have no chance of reaching the object. Of course, in future wars, in which the torpedo-boat is called to play a very important rdle, the attack of vessels by these much-feared little boats will principally be carried out during dark. In consideration of this, most Navies are furnishing their ships with one or more electric lights, in order to be better enabled to detect the approach of these craft at some distance from the vessel. It is easy to imagine the valuable service the Revolving Cannon will be capable of rendering, when used in conjunction with the electric light. Besides these experiments, the accuracy of fire, etc., was determined against a fixed target. The results are contained in the following table :� 53 RAPID FIEING. THE Q-TJN TRAINED FROM THE SHOULDER.* Number Time Dimensions Number Mean Deviations. Range. of rounds of of of fired. firing. targets. hits. Vertical. Horizontal. ! Metres. Seconds. cm cm 500 20 47 \ 15 111 98 500 900 20 20 30,5 63 5met-X5met- 16 11 106 82 163,5 76 900 20 60 14 91 127 1400 20 80 \ 10met- high ) 5met- broad 14 69 90 COMPARISON OF THE RAPIDITY OF FIRE OF REVOLVING CANNON WITH THAT OF MITRAILLEUSES. In comparing the rapidity of fire of the Revolving Cannon with that of the well-known mitrailleuses of Gatling, Palmcrantz and Montigny,** it must be remarked that the apparent greater rapidity of fire of the mitrailleuses is illusive, because under rapidity of fire must be understood the time necessary to load, point and discharge a gun, and not the time required to load and fire only. This may be called rapidity of the mechanism, but it is often mistaken for rapidity of fire. At a comparative trial between the 37mm Hotchkiss Revolving Cannon and the Service Gatling Grim of the British Navy, at Portsmouth, in July, 1878, when both guns were mounted side by side on board H.M. gunboat " Comet," and were worked under steam, at Spithead, against floating targets, it was proved that at sea, where sighting is necessary for each round, the rapidity of fire of the Revolving Cannon is about equal to that of the " Gatling,'7 although the rapidity of mechanism of the latter is at least three times as great. Resides this, the steel plates of torpedo-launches are proof * It must be remarked tliat on this occasion the gun was worked by two different men, which accounts for the great irregularity in the deviations. ** The two last-named inventors, following the idea of Mr. Hotchkiss, have lately, too, endeavoured to construct their guns so as to fire a small explosive shell. 54 against the bullets of the Gatling gun, and the accuracy of its fire, as well as the range, was considerably inferior to that of the Revolving Cannon. It must also be borne in mind that each shell of the Revolving Cannon gives on explosion from 15 to 19 dangerous fragments, so that the bursting effect compensates for rapidity of fire, and its fire is thus rendered more effective than that of any class of mitrailleuse. For naval service, where a gun is subject to all movements of the vessel itself, and has to fire against rapidly-moving objects, the Revolving Cannon, mounted on its universal pivot, and trained from the shoulder something in the style of a rampart gun, so that it can be pointed for each round, a rapid and very precise fire can be opened at 2000met* range, of sufficient power to disable or destroy any torpedo-boat in service at the present day. The Revolving Cannon is capable of delivering a slow fire of great precision at long ranges, whilst it possesses at the same time the advantage of being able to direct a stream of explosive shells, or steel shot, with the rapidity of about 60 rounds per minute, when the assailant has perhaps, during dark, arrived unobserved within close quarters. CHAPTER VII. THE REVOLVING CANNON FOR CERTAIN PARTICULAR PUEPOSES.�THE HOTCHKISS MITRAILLEUSE.�THE 40 mm GUN FOR FLANKING THE DITCHES OF MODERN FORTIFICATIONS.�THE 47rani REVOLVING CANNON FOR NAVAL SERVICE.�THE 53mm REVOLVING CANNON. The system of the Revolving Cannon is not restricted to any particular calibre ; it can be constructed either as a mitrailleuse, which employs small-arm ammunition, or of calibres much larger than the before-described guns. Guns as large as 53mm calibre are manufactured; and there is no practical difficulty in constructing still more powerful calibres, thereby affording the advantage of uniformity in the system of armament, as far as concerns machine-guns. THE HOTCHKISS MITRAILLEUSE. This arm entirely resembles the Revolving Cannon in its construction ; but it is generally made with nine instead of five barrels, the motion of the crank being accelerated by two helical wheels, to give a rapidity of fire of about 200 shots per minute. This comparatively slow fire has been adopted to insure the perfect and reliable action of the gun, as it is known that most of the defects in the working of other systems of mitrailleuses are due, in great part, to the excessive speed at which the mechanism has to work, and the impossibility of being able to supply the gun with ammunition with the necessary precision and order. The rapidity of 200 rounds per minute allows the application of the simple mechanism adopted for this arm, and it is also with it to be less feared that ammunition may be unnecessarily wasted, as is the case with guns firing excessively fast. 56 The cartridges, packed parallel to each other, are carried in feed-cases, each case holding twenty-five cartridges. Mr. Hotchkiss does not manufacture his gun to fire small-arm ammunition, unless specially desired, as it is the use of a small explosive shell which is one of the particularly valuable features of the Hotchkiss system. THE 40mm REVOLVING CANNON, FOR FLUNKING THE DITCHES OF MODERN FORTIFICATIONS. This gun is specially construted to fire canister shot, as well as explosive shell. By an entirely new ballistical principle it has been made possible to cover a prismatical ditch, over its entire length with an equally well-divided hail of bullets�1500 to 1600 per minute�from a few metres from the muzzle of the gun to a distance of several hundred metres.* Weight of gun....... 450kiL Weight of canister shot . . . . . 870gr Number of balls in each canister . . . . 24 Weight of explosive shell..... 680gr Charge of powder . . . . . . 90 ^ THE 47mm REVOLVING CANNON FOR NAVAL SERVICE. In the 47mm Revolving Cannon the general disposition of the light 37mm naval gun has been adhered to. It is mounted in the same manner, on a universal pivot, and is directed and fired from the shoulder by means of the stock, so that each round can be pointed with great rapidity and precision during slow, or rapid fire. Like the 37mm gun, this gun has no perceptible recoil; and as it discharges either a steel shot, or explosive shell, weighing l,100kiL, it may be regarded as a regular small rapid-firing cannon, in which no time is required for loading or running out, etc. * It is desired that the details of construction of this special model of the Revolving Oannon should for the present not be known, therefore no explanation is given of the manner by which the somewhat curious results are obtained. 57 This gun is designed principally for arming launches, and its weight� 550ML�does not much surpass that of the guns, with their carriage, ordinarily used for this purpose. This gun, on account of its greater power, will sometimes be preferred to the 37mm model for the armament of ships. Its projectiles are capable of perforating steel plates of 20mm thickness up to 2000 met< range, and at an oblique angle of fire within 30deg', so that it can be used for damaging the superstructure and unarmoured parts of ironclads and powerful vessels of the merchant navy, which are fitted out as cruisers during a war, as well as any torpedo-boat it might be possible to construct for some time to come. The new rapid steel cruisers and despatch vessels which are now being introduced in some Navies will not be able to resist the punching power of the projectiles of this gun. The rapidity of fire of this 47 mm calibre Eevolving Cannon is nearly the same as that of the light 37mm model�that is to say, from about 20 carefully-aimed shots per minute, up to about 60 rounds, during a critical moment of an engagement. In this model two turns of the hand-crank are necessary to complete the operations of loading, firing and extracting the empty cartridge-case. The gun gives an accoustic signal to the gunner when the two turns of the crank have been completed ; he then (as in the 37mm gun) stops, points and by a slight forward motion of the crank, he fires the gun. The stock, or shoulder-piece, of this gun is of a somewhat different construction to that of the 37mm model. The bottom arm is extended downwards and is fitted with three handles, one above the other, so that the gunner, in bearing the stock to his left shoulder, grasps (according to the required elevation or depression) one of these handles with his left hand, instead of a directing-handle under the breech, his arm being then in a vertical, outstretched position. This arrangement tends to give more leverage for pointing and working the gun. PRINCIPAL WEIGHTS, DIMENSIONS, ETC. Weight of gun............ 550kil- Weight of universal pivot with its socket....... 135 m- I Number........... 5 ) Calibre............ 47 mm els. Length (25 calibres)......... 1175 Weight of each barrel ........ 44 8 mm kil. 58 Number of grooves ......... 16 Depth of grooves ......... 0,4 mm Billing. { Width of lands.......... 3 mm Pitch of rifling, one turn in ...... . 1500 mm Twist, depth and width uniform ....... Total length of gun........... 1,730 met AMMUNITION. Weight of steel cored-shot .......... 1,100 ML Total weight of shell........... 1,100 HL Weight of bursting charge . . . . . . . . . . 45 gr Entire length of projectile.......... 135 mm Weight of metallic cartridge-case . . . . . . . . . 150gr Total weight of complete cartridge . . . . . . . 1470gr Total length of complete cartridge......... 234 mm Charge of powder.......... 200gr Initial velocity of projectile.......... 425 met REVOLVING CANNON OF 53mm CALIBRE. Up to this date the 53mm gun is the heaviest calibre which has been constructed on the Hotchkiss system; it is principally intended for certain services in fortifications, and to be used as a bow and stem chaser on vessels, etc. This gun resembles in general features the heavy model Revolving Cannon for field service, but it is a gun of much greater power. The ammunition is also similar to the before-mentioned gun. A metallic cartridge-case holds the charge, projectile and primer, combined in one. The cartridges are placed singly in the feed-trough of the gun, and from thence they are automatically distributed to the barrels and then fired. Like all other machine-guns on the Hotchkiss system, this, too, is without recoil, and the barrels are without movement at the moment of the discharge. The rapidity of fire is about 30 rounds per minute. 59 PRINCIPAL DIMENSIONS AND WEIGHTS OF THE 53mm REVOLVING CANNON AND ITS AMMUNITION. Calibre............. 58mir Total length of bore (24 calibres) ........ 1272 mn 1 Pitch of rifling one turn in . . . . . . . 1507 mn Twist, depth and width of grooyes uniform Number of grooyes . . . . . . . .16 Depth of grooves ........ 0,5 mn V Width of lands......... 3 mn Total length of gun.......... . 2me' Weight of gun.........! . . 1100kil- / Total weight of projectile (shell)..... 1,800 kil I Bursting charge . . . . . . . . 75 gr Ammunition. < Length of projectile ....... 170 mn I Length of entire cartridge . . . . . . 310mn \ Weight of complete cartridge ...... 2,460 kiL Charge of powder............ 360 gr Initial velocity of projectile ......... 450 mel LIST OF PLATES. 1. Geometrical Drawings and Sections of Gun and Carriage. 2. Revolving Cannon, Carriage and Limber. 3. Revolving Cannon on Field Carriage. 4. Geometrical Drawings and Sections of Revolving Cannon for Naval Service. 5. Revolving Cannon, as Mounted for Service Afloat. 6. Ammunition used with the Gun. 7. Twelve Burst Projectiles, showing Fragmentation of same. 8. Steel Targets Perforated by Common Shell of the Revolving Cannon. 9. Steel Target representing the Bow of H.M. Torpedo-Boat a Lightning" Perforated by Common Shell of the Revolving Cannon. 10-14. Series of Targets made with the Revolving Cannon at Sandy Hook, U.S.A. 15. Targets representing a Steam Torpedo-Boat (Experiments in Holland). Printed by T. Symotsds, 10, Rue Rochechouart, Paris. HOTCHKISS REVOLVING CANNON. FOR field service Plate'I. Elevation 110 Elevating and lateral training apparatus Vertical section through the trunnions Plan 1:5. Hand- crank DETAILS OF THE MECHANISM Scale 1.5. Worm. Crank-shaft T Extractor-crank. Thumb--screw. Firing-pin Cog-wheel Front- view of breech-block 1: 5. /j"ran==\7^" JKz EES -^ar- Spri Extractor Loading-piston. 111 .S raise-et Ccfartter 43. R.cfa Dwtkercjue,i Fares (j^J 73 PLATE %. HOTCHKISS REVOLVING CANNON FIELD CARRIAGE AND LIMBER PLATE 3 HOTCHKISS REVOLVING CANNON ON FIELD CARRIAGE HOTCHKISS REVOLVING-CANNON. FW naval service Plate * (HS5) A.Braise et Courtier 43.HdeMwikcrque Ptaie . ( ?s) PLATE o | IIOTCHKISS REVOLVING CANNON AS MOUNTED FOR SERVICE AFLOAT PLATE 0 AMMUNITION FOR HOTCHKISS REVOLVING CANNON 1. Projectile, showing grooves under band. 2. Fired projectile. 3. JSteel shot.. 4. Canister-shot. 5. Complete cartridge, with explosive shell. Plate 7. Photo6lyptie Lemercier & C"1 Paris BURST PROJECTILES OF HOTCHKISS REVOLVING CANNON CAL.37m/m. WEIGHT 525 <5r. BURSTING CHARGE 25gr. 12 SHELLS. 308 FRAGMENTS PLATE 8 4 � it^r^: t # � FRONT AND BACK VIEW OF TARGETS PERFORATED BY COMMON SHELL OF HOTCHKISS REVOLVING CANNON, CAL. 37m.m. NAVAL MODEL Target N' 1. Steel plate (imm thickness. Striking velocity l-i'met. corresponding to 2000met range Fs� 2. N� 3. a 12 � (( 1,') (( 2115 � 330 � MO n 230 � PLATE 9 TARGET REPRESENTING THE BOW AND FIRST BULKHEAD OF H. M. TORPEDO"BOAT � LIGHTNING- � PERFORATED BY COMMON SHELL OF HOTCHKISS REVOLVING CANNON, 37mm. CAL., NAVAL PATTERN. Direction of fire parallel to line of keel. Striking velocity 330 lne'-, corresponding to 230'"*'- range. �4�> Q-4 s c: CO !!!.. >*-� ,1 1 t % * * * % e *b htrf- *� %s* Jr.__I :,.',�'�. < � , ' f. -V 1<;. � i i' * � rt ��; *': i < l!J .\, I' � ! it J i < tfi / J % x x X * r/> *z%;%h >* v % % ' 1 (� 'l \ . * \.i � � ^ J �* �*� * * 4 * *�* **�& %* ** ' \' ----1 V,, CO OO k-------p-* -I�* c-c>C ^ ^ ^ r * s * %* * ? %_% Mi � Mi r * I' > j i;\/V � h 'ii X' T !*" �"** vm i^ fe. "*^ D '� ^.^^ IDlllhh/ -5^1 k * * ** V t V i 4 I' 4 . ,'. o CSI +-� CO CO C. J;: hi!, \JM ^ / < 7 : M � *% hi A "***.' :!.i^ ;K ^; f . i iY > .\ r- * ^1 Uw X v V ^ % ^ * ^^ ^ V cS ?? ^J � \ < 4x .. v i * * A^i ^r^ ^"^ ^f~^ ^-fOfOOcO^CqcO^jtOcO o ^ % s / % (if r % f: *�* SS i �� j ;;fw +% % tX%\ % \^�^%^ � ^ * t. i �%rH * % % �' i \ ( fill % * ^ 4# ^% ^ s * v % 11^ K � 1 II" 111 "llillllil^/ :sy9$ie}uo sjiiijo jaqumg * % ;��� c -----S-* %*% o ^ 5 P-t F-i o � II ^ |25 ^ M K. v * r\ v � � %M '*% S' V^ I* .%* \ I � �* i � i'i ; * < i V),. f . V ll 'JI3 >\ SI i < V . AW * .9- U'4* ' I � \1 i * % ^ * � �� '��d :^;^ V S iiiL Iw 1% v s * � * ^r- ^ � Ph re; tcj -1 to � M o cd ft ^ ^ ^ a- . P-. ^ Qi S s 3 R �^-H CQ �+o ^. 1*\� �-, f ! Ji / j^l ii H .'i: �v i f fc. V M l H " ?? '1 H'^r if. !U Jjik V iv l ' il ! a, ! t � � \ N 'r 1 ^ >-1 03 � P5 TRIALS WITH HOTCHKISS REVOLVING CANNON S/'WCAL.AT SANDY HOOK N.Y. 25 January 1877 RESULTS at 200 yards (183m-et) r------ Weight of projectile �_ 520 Or? f" dumber of rounds fired �� 100 ------------------------------------------------.--------------^ � Direct hits I Throughi hits by fragments a Hits not through. �"3 /�*_ _ ~"~i*<-,. _�"-����� �"� + A + + A ? A * A � ' +*______� *0 i' * *___� t0*>^ ( --� ? A ? A ? vl + *S A ?* A * ^ ?_______j t *____________^_________, Plate. 11.. j � J jj- # � �- f A ' * 'i � < ? I * * i * 0 0 0. 0 . * '* � * * * * *�< * ,< * + * ------------------:-------------------------�----------�----------------------------------JL------�__------__------,--------i r*~4 * � 1 0 ? t f * A f 0 A i . I warn � � ' ... "ii. i. -------------------- a # f----------^------------ ' � . ' i # .' ' .* ' A * * 0 , ' * * a\ < * A A 0 � A � � '# '** � 0^0 A � A * 4 + A <_"____......__"______________4 >�______________1__ r A mooter onibpPl^ /BSS^MB ot to/rt 1,2.6/92. 63 &v <: Total numler of hits on loth targets MS. (Sfyned,) Frank H:Fhipj>s Capt. of Ordnance, Recorder. Distance of first target from gun 183 mfl (U4rZ) A Jrffisc &> CnurtUr, 43 JL del)unkerju^foris (1*.$ TRIALS WITH HOTCHKISS REVOLVING CANNON 37**CAL.AT SANDY HOOK N.Y. 2 December 1876 Plate 12 RESULTS at 1000yards (915^) "�/� t^4 -------A Weight of projectile � __ 520�r NiimbeT of rounds fired: 143- (If round* fired lofvnil lh& dcvtrflvnj) � Bircvb Tiifc / Through, hits bu friujnuenis A Hits rwt through^ ,Y_____ A # ? + 4 # ? A A * A \ * 1 # * A\ + A ? << / * , * < A /. *! a A 4 A # ? >r <* * # # < , < #* �* * , " * J ? A J>_____4L. � ? *< % "*?'� � # >t ? * ? #- -i ? * # X A ?# * �tf � * - - * ?� ', * � * ? -7 -......-' .' �> -~y ��nfu / ,'tfc ... < k * A # ? r*r,.. '�r �^., -^'" _^- 1� 4 � y c^ # A ? # _^---------------_ �1 i 0 # ? * # " >� #4 � ? / * * * # � # # ? /L#>i #A ^ # ^ / ^ ^ ?* * ##^ / - / - / / i i i i i -.7- ;V;:7/ //^ . //J, �3-3- ^//^-------*- **~> ^ > * p'-" .^-, (Sijncd) Fiauk Jl.Fhijps. Cupt. of Ordnance.'. Recorder. Number of hits on target ___N?l �112/24 a 9 ___. . 2 � 23 / 276 a 102 .___ . 5 � 5 / 2S4 ^ 14 5 ___ . # � 2 / 194 a 108 Total mimler of hits on the 4 targets 1285. (UIH2) A. 3roCn<. A- Cowtier ,A3Riie Jhmkeiyuc Paris (j8) to ?* CD ^po h* 33 te? | C � -23 '5 coxde Xj � ^ > >�-� ^ C H2> n- to u0 rO o o o -� > si CZD CN3 �5 uo x�f "1 1 14 1 if red the o c� H 1 ,) CO � �>. ^-CS "> s^ o �S p-l J C4-� C+-* ^V o o JcJ CD *>5 Job HP *�4 5 E TRIALS WITH HOTCHKISS REVOLVING CANNON 37"WCAL.AT SANDY HOOK NY. 2.DecemW.1876 Plate. 14. RESULTS at 2000 yards (1830m-et) Weight of projectile: 520 Gr. Number of rounds fired : 170 (7 Rounds firaL to find' ihc elevations) � Hired hila. I Through* hits by Jbagments. a IftZs not through;. *<**� *� ^ M"t - 0 A * ? 4 ><# AAA A A\ jm - / ~ ^ ^ <�M~'*> 3**2 ^T* ****T m * * + � A A * * A * A * * * A A+ A A t* A * A A * + A *+ _ A ' .4 �� * A_______- A �� "�/ -#^----^r#- " * � 1 -1 * * AA *\ A #H# 1 A> A + # A + A A A* * A a A m A ^ W A + A � A * � a # -i * A ' k A ^ A * A + A 4+ A �� �<_ A A *----7" #^ # < � *? ' * # A # * # >f # A * Ji W - * + \ * , �r - ? A % * * A A 4 A "' # 4 ^ � ^^ ^^':_____--� ^> j&* �^ 7 , _< t^' //� - >" ^ *��- - �* />.. i^^^, - ** *�*�� N?l -y r ._- C, -�_ ^-^^ ^� ^ �� # � * # # � A * A 0 + + # #i -f �-! ^ A * * + +*\*A * 4 %A a � a �,* i *� __i__^___y n- i. / *ht *A4 ^ ^#>� * a * m* # A A 1# W 'I A * A *^* # ^4 A A * *A A. + A a . * A\ + A - * A- + ~ < * - f If -1 � * * # 4-' # *4 \+ i* A S' * A A A A *4 + A A A ' '" _/�^ '- ^ 7 /^*f ^- ^2>-� % / . ^'- ^ '"/ft.- ..^ e c-w* Numler of Ms on target-.................... M?l � 50 / 192 a 170 ............................ . 2 � 31 V 126 a 176 ............................... S � i i 64 a 81 ............................. , 4 � 2 / 25 .42 (Signal) Frank E Thipjts. Copt, of Ordnances. Recorder Total numler of hits on the 4 targets� 96$ (UU15) A.imst. k Cvurticr, lii.K.JcDvtniurgtu.Tuna i^ujt) TRIALS WITH HOTCHKISS REVOLVING CANNON,AT HELDER (HOLLAND) 11-12 SEPT. 1878. GUN MOUNTED ON STARBOARD BOW OF IRON-CLAD RAM ."GUINEA"! Plate. 15. DIMENSIONS OF TARGET representing a Thomycroft steam torpedo -"boat (fcul-sizej length, over all............... 23 met Width ...............................;...*./... Height aiorc water, bow...........1.0 , -.......*. ..stern,.......0.7 - � lenath of cabin...................13.0 , Width, of cahin,....................1. 3$. Heiaht of cabin- abort deck......0.6$'.. . Heiaht of connma torrer.........0.3$ , Diametre of auto.....................OJ . Height of funnd.............1.0$. Duxnutro of ditto .................O.M . ^-k* 0� f.t Guinea, at anchor 6oo"? from torpedo-boat. % rounds fired ut lnt20s It direct hits - $0 % Z ~ * Guinea, at anchor 600�* from brpedo-boat. Z8 rounds fired 20 du>cct hts - J11/z % 3^*GuwMz~\