Part 2 of 2

+---------+----------+-------------+----------+----------+-----------+ | | | Penetration | Muzzle | | | | | Muzzle | in | Energy | Weight | Weight of | | GUN. | Energy. |Wrought-iron.| per Ton | of Gun. | Carriage. | | | | | of Gun. | | | +---------+----------+-------------+----------+----------+-----------+ | | Ft.-Tons.| Inches. | Ft.-Tons.| Pounds. | Pounds. | | 5-inch | 1,525 | 10.7 | 552 | 6,187 | 4,200 | | 6-inch | 2,542 | 13.2 | 521 | 11,000 | 6,400 | | 8-inch | 7,285 | 18.2 | 560 | 28,000 | 14,000 | | 10-inch | 15,285 | 23.7 | 588 | 58,240 | 32,482 | | 12-inch | 25,985 | 27.6 | 591 | 44 tons | .... | | 14-inch | 41,270 | 32.2 | 550 | 75 tons | .... | | 16-inch | 61,114 | 36.8 | 571 | 107 tons | .... | +---------+----------+-------------+----------+----------+-----------+ This _energy_, total energy, expresses the work that the gun can perform. It is expressed in foot-tons, and signifies that the energy developed is sufficient to raise the weight in tons to a height of one foot. Thus the projectile from the small 5-inch gun, weighing sixty pounds, fired with a charge of thirty pounds of powder, leaves the gun with an energy capable of lifting 1525 tons to the height of one foot! Comparing this with the energy developed by the 100-ton hammer at the forge of Le Creuzot in France, the energy of which is 1640 foot-tons, we have a most striking illustration of the power of gunpowder, and the testimony in the table as to the energy developed per ton of gun more forcibly exhibits the perfection of a manufacture which, with so little weight of gun, can develop such gigantic power. [Illustration: UNBURNED AND PARTIALLY CONSUMED GRAINS OF U.S.N. POWDER] It is this power, united with a moderate weight of gun, which will enable our unarmored cruisers to hold their own with vessels moderately armored. The power of the battery is greater than is required to contend with unarmored ships, there is a great surplus of power of offence, and the effort is very properly made to sustain this at the highest practicable point. The table shows that the 5-inch gun can perforate 10.7 inches of wrought-iron at the muzzle; but the results given in tables are based on deliberate firing made on a practice-ground, with the position of the target normal to the line of fire. Such conditions cannot obtain during an action at sea, for, besides the modified effect caused by increased distance of target, it must be borne in mind that the side of an enemy’s ship will be presented at varying angles, which introduces the element of deflection, than which no cause is more detrimental to penetration. Though the table states a fact, the practical effect of the projectile will be far less than is stated, hence the wisdom of providing a large surplus of power to compensate for the resistance to its operation. [Illustration: SECTION OF U.S.N. 6-INCH BUILT-UP STEEL BREECH-LOADING RIFLE.] It will readily be conceded that the artillerist has a very responsible duty to perform in so designing his gun that the parts shall lock and interlock to guard against chance of dislocation in the structure. A study of the illustration of the 6-inch built-up gun as constructed at the Washington navy-yard will show the system there adopted. [Illustration: BROADSIDE CARRIAGE FOR 6-INCH BREECH-LOADING RIFLE.] In the list of guns each calibre is represented by one gun. We have not, as of old, several guns of the same calibre differing in weight; multiplicity of classes will be avoided; but this will apply only to the main battery, for history is singularly repeating itself at this time in the restoration of the “murdering pieces” which have been cited as forming part of naval armaments in the seventeenth century. The needfulness of machine guns for operating against men on open decks, for effecting entrance through port-holes, for repelling attacks in boats, and for resisting the approach of torpedo-boats, is so widely recognized that no vessel of war is considered properly equipped without a secondary battery of these “murdering pieces.” They are mounted on the rail, on platforms projecting from the sides and in the tops. The types adopted in the United States navy are the Hotchkiss revolving cannon and rapid-firing single-shot guns, and the smaller calibre machine guns of Gatling. The heavier pieces, throwing shells of six pounds weight, are very effective against vessels of ordinary scantling. In contemplating the present condition of our new naval armament we have the consolation of knowing that, so far as concerns the study of the subject generally and in detail, the designs, and the initial manufacture, all has been done that could have been done with the resources available. What has been achieved has been without the facilities that are provided in modern gun-factories; but notwithstanding all the drawbacks, it is probably safe to assert that no guns in the world to-day are superior to those that have been fabricated at the Washington navy-yard of steel on the new adopted pattern. The work at this ordnance yard is carried on without ostentation; there is no flourish of trumpets accompanying its operations; it is not advertised, and the people do not yet know how much they owe to the ordnance officers of the navy for the initiation of this new industry, which enables us to assert our ability to advance in this manufacture through the incontrovertible proof of work accomplished. The results are meagre in quantity, and at the present rate of manufacture it will require many years to equip our fleet with modern artillery; this should be remedied, as there is now no doubt as to the success of the productions of this establishment. The plant should be enlarged on a liberal and well-matured plan, and the work should be encouraged by generous appropriations. [Illustration: RAPID-FIRING SINGLE-SHOT HOTCHKISS GUN.] It may not be generally known that the steel forgings required for the few 8-inch and the two 10-inch guns now in hand were imported from abroad, for the reason that they could not be furnished of domestic manufacture, from the want of casting and forging facilities in the United States for work of such magnitude. This was a deficiency in our resources that required prompt attention to secure us a position of independence in this important matter. The method of achieving the object was carefully studied out by a mixed board of army and navy officers, and presented in a document known as the “Gun Foundery Board Report,” and the subject received the attention of committees from both Houses of Congress. All of these reports virtually agreed as to the method, but there was a useless delay in action; large expenditures of money were required, and there was hesitancy in assuming the responsibility of recommending it. The object was of national importance, however, and public opinion demanded its accomplishment. The officers of the navy have proved their ability to carry on the work successfully; and if the opportunity be given they will establish the artillery of the United States navy in a position of which the country may again be proud. NOTES. GUNS. The United States no longer depend upon foreigners for guns or armor, inasmuch as the circular issued in August, 1886, by the Navy Department inviting all domestic steel manufacturers to state the terms upon which they were willing to produce the steel plates and forgings required for ships and ordnance, has met with a prompt response. About 4500 tons were needed for armor, in plates varying from 20 feet by 8 feet by 12 inches thick, to 11.6 feet by 4.3 feet by 6 inches thick; and of the 1310 tons of steel forgings, 328 tons were intended for the 6-inch guns, 70 tons for the 8-inch, and 912 tons for the calibres between 10 and 12 inches, both inclusive. The rough-bored and turned forgings required by the contract were to weigh 3¼ tons for the 6-inch calibres, 5 tons for the 8-inch, 9½ tons for the 10-inch, 9¾ tons for the 10½-inch, and 12½ tons for the 12-inch. From the time of closing the contract twenty-eight 6-inch forgings were to be delivered in one year, and the remainder within eighteen months. All the 8-inch were to be ready within two years, and the 10-inch and larger calibres within two years and a half. The proposals opened on the 22d of last March showed that for the gun-forgings the Cambria Iron Company had bid $851,513, the Midvale Steel Company $1,397,240, and the Bethlehem Iron Company $902,230; and that for the armor-plates the Bethlehem Company had bid $3,610,707, and the Cleveland Rolling-mill Company $4,021,561. Subsequently the Navy Department awarded the contract to the Bethlehem Company, which agreed to furnish all the required steel at a total cost of $4,512,938.29. The tests are so rigorous that a high quality of steel is sure to be produced. The specifications require the forgings to be of open-hearth steel of domestic manufacture, from the best quality of raw material, uniform in quality throughout the mass of each forging and throughout the whole order for forgings of the same calibre, and free from slag, seams, cracks, cavities, flaws, blow-holes, unsoundness, foreign substances, and all other defects affecting their resistance and value. While it is prescribed that the ingots shall be cast solid, latitude is given to the method of production; but no matter what method may be employed, the part to be delivered for test and acceptance must be equal in quality and in all other respects to a gun ingot cast solid in the usual way, from which at least 30 per cent. of the weight of the ingot has been discarded from the upper end and 5 per cent. from the lower end. For breech-pieces each ingot must be reduced in diameter by forging at least 40 per cent.; in case tubes are forged upon a mandrel from bored ingots, the walls must be reduced in thickness by forging at least 50 per cent. Forgings are to be annealed, oil tempered under such conditions as will assure their resistance and again annealed, and no piece will be accepted unless the last process has been an annealing one. The forging must be left with a uniformly fine grain. All these excellent results are the direct outcomes of the report made in 1884 by the Ordnance Board. 1st. That the army and navy should each have its own gun-factory; 2d. That the parts should be shipped by the steel-makers ready for finishing and assembling in guns; 3d. That the government should not undertake the production of steel of its own accord; 4th. That the Watervliet Arsenal, West Troy, N. Y., should be the site of the army gun-factory; and 5th. That the Washington navy-yard should be the site of the navy gun-factory. No action was taken upon the recommendation to establish gun-factories; but at the first session of the Forty-ninth Congress an appropriation of $1,000,000 was made for the armament of the navy, of which sum so much as the Secretary determined might be employed for the creation of a plant. Under this permission the gun-factory at the Washington navy-yard is now being established. The construction of the breech-loading steel guns for the new cruisers has been energetically pushed. Slight modifications in the original designs were made necessary by the adoption of slower burning powder, which carried the pressure still farther forward in the bore, and, in the case of some foreign guns, caused their destruction. Though our guns have not suffered from any such accident, it has been deemed a wise precaution to give the 8-inch guns of the _Atlanta_ two additional chase hoops, and to hoop all other pieces of this calibre to the muzzle. From a memorandum kindly furnished by Lieutenant Bradbury, United States navy, it is learned that the number and calibre of the new guns now finished, under construction, or projected, are as follows: +------------------------+--------------------------------------------+ | NAME OF SHIP. | Calibre. | +------------------------+--------+--------+--------+--------+--------+ | | 5-inch.| 6-inch.| 8-inch.|10-inch.|12-inch.| | Dolphin | None. | 1 | None. | None. | None. | | Atlanta[53] | ” | 6 | 2 | ” | ” | | Boston[53] | ” | 6 | 2 | ” | ” | | Chicago[54] | 2 | 8 | 4 | ” | ” | | Gun-boat No. 1[54] | None. | 6 | None. | ” | ” | | Gun-boat No. 2 | ” | 4 | ” | ” | ” | | Newark | ” | 12 | ” | ” | ” | | Baltimore | ” | 6 | 2 | ” | ” | | Charleston | ” | 6 | None. | 2 | ” | | Miantonomoh | ” | None. | ” | 4 | ” | | Terror | ” | ” | ” | 4 | ” | | Amphitrite | ” | ” | ” | 4 | ” | | Monadnock | ” | ” | ” | 4 | ” | | Puritan | ” | ” | ” | 4 | ” | | Armored cruiser | ” | 6 | ” | 4 | ” | | Armored battle-ship[55]| ” | 6 | ” | None. | 2 | | 2 Gun-boats | ” | 12 | ” | ” | None. | | 2 Cruisers | ” | 24[56]| ” | ” | ” | | Floating batteries | ” | None. | ” | ” | 8[56]| +------------------------+--------+--------+--------+--------+--------+ This gives a total of two 5-inch, one hundred and three 6-inch, ten 8-inch, twenty-six 10-inch, and ten 12-inch. In his last report, Captain Sicard, Chief of Ordnance, states that “for the new ships approaching completion we have eighteen 6-inch, three 8-inch, and two 5-inch guns finished, and three 6-inch and five 8-inch well advanced, together with all the carriages for the _Atlanta_ and _Boston_, and all for the _Chicago_, except the 8-inch.... With brown powder the following are the best results obtained in the 6-inch and 8-inch guns. +-----------+--------------------+---------------+-----------+ | GUN. | Powder. | Muzzle | Pressure. | | | | Velocity. | | +-----------+--------------------+---------------+-----------+ | | | Foot seconds. | Tons. | | 6-inch | American Brown. | 2,105 | 15.6 | | 8-inch | Westphalian Brown. | 2,013 | 15.5 | +-----------+--------------------+---------------+-----------+ “It will be observed,” he adds, “that the muzzle velocities are as high, while the chamber pressures are considerably below those which the guns were calculated to support in service.” During the preliminary trials afloat of the _Atlanta’s_ battery in July, a few minor faults were unfairly given an importance by the newspapers which led the country to believe that the ship and her armament were useless. Unfriendly critics vented their spite and aired their ignorance in condemnations which included all who had had anything to do, even in the remotest degree, with the design and construction of vessel and gun. Indeed, so bitter and persistent were they that for a time it seemed almost hopeless to expect any further good could come out of the Nazareth of public opinion. It was not a question of politics, for the journalists of every political faith ran amuck riotously upon the subject; nor was it a matter of morals, where, through intelligent discussion, better things could be attained, for with brilliant misinformation and dogmatic dulness each scribe stuck his pin-feathered goose-quill into the navy’s midriff—it being such an easy, such a safe thing to do—and then thanked Heaven he was a virtuous citizen. Finally, a board was appointed to inspect the ship and battery, and after a thorough examination it made the following report: “In obedience to the Department’s order of the 22d instant, the Board convened on board the _Atlanta_, Newport, Rhode Island, on the 25th instant (July, 1887), and made a careful examination of the ship, guns, carriages, and fittings, and of the damage sustained during the recent target practice, as reported by the board of officers ordered by the commanding officer of the _Atlanta_. The Board proceeded to sea on the morning of the 25th instant, but were prevented from firing the guns by a heavy fog which prevailed throughout the day. The ship was again taken to sea on the morning of the 27th instant, and the guns were fired. No deficiencies were noted in the guns themselves other than a slight sticking of the breech-plug in 6-inch breech-loading rifle No. 5 (this disappeared during the firing), some difficulty in the management of the lock of 6-inch breech-loading rifle No. 4, caused by slight upsetting of the firing-pin, and the bending of the extractor in 6-pounder rapid-fire No. 5. “The recoil and counter-recoil of the 8 and 6 inch guns were easy and satisfactory, except at the second fire of the 8-inch breech-loading rifle No. 1, when the gun remained in. (This was readily run out with a tackle.) The action of the carriage of 8-inch breech-loading rifle No. 1 at the first fire was due to want of strength in the clips and clip circles, and at the second fire to want of sufficient bearing and securing of the deck socket. It is believed that had the deck socket held, the carriage would not have been disabled by the giving way of the clips. The training gear, steam and hand, was uninjured; the gun was readily trained when run out to place. The action of the after 6-inch shifting gun No. 4 was satisfactory, notwithstanding that the front clips had a play of half an inch. The action of the broadside carriages of 6-inch guns Nos. 5 and 18 was satisfactory, except the breaking of clips, the starting of the copper rivets in the clip circles, and the wood screws in the training circles. “It is believed from the action of the carriage of 6-inch breech-loading rifle No. 5, when the clips were removed, that the carriages can be safety used without clips. The clips, however, give additional security and steadiness to the carriage, and assist the pivot and socket in bearing the shock of the discharge. The firing of the 6-pounder rapid-fire guns developed a weakness in one leg of the cage mount of No. 4, due to imperfect workmanship, and showed also the necessity of locking nuts on the bolts that secure the mounts to the ports. The tower mounts of the 3-pounder rapid-fire guns are unsatisfactory. They cannot be moved with facility; the line of sight of the gun is obstructed at ranges beyond 1600 yards, and the guns cannot be safely used as now fitted. For this reason 3-pounder rapid-fire No. 3 was not fired. The tripod mounts of the 1-pounder rapid-fire guns need stronger holding-down arrangements. The tower mounts of the 47-millimetre revolving cannon are like those of the 3-pounder rapid-fire guns, and have the same defects. The mounts of the 37-millimetre in the tops are satisfactory. “Careful observation of the effect of the firing upon the hull of the vessel failed to develop any damage other than the breaking of the cast-steel port-sills and the starting of some light wood-work. The shock of discharge was slight on the berth-deck, and observers there were unable to observe which 6-inch gun had been fired. The deck, hull, and fittings, with the exception of the port-sills, hinges to superstructure doors and vegetable lockers, and some of the light wood-work, have every appearance of strength and ability to endure the strain of continuous firing of the guns. The blast of the forward 8-inch gun, when fired abaft the starboard beam, will not permit the crews of the starboard 3-pounder rapid fire and 1-pounder rapid fire to remain at their guns. When the after 8-inch gun is fired forward of the port beam, the crews of the after 47-millimetre revolving cannon and of the port after 1-pounder rapid fire cannot remain at their guns. When the forward 6-inch shifting gun is fired on the port bow or directly ahead, the crew of forward 8-inch gun cannot remain at their places. When the after 6-inch shifting gun is fired on the starboard quarter or directly aft, the crew of the after 8-inch gun cannot remain at their gun. The inability to fire parts of the secondary battery under certain conditions is due to the great arc of fire given to the 8-inch guns. This can hardly be called a defect. It is thought that a screen can be placed between the 8 and 6 inch guns which will enable them to be worked together forward or aft. “The pivot socket of the 8-inch carriage should have a broader bearing surface, and should be rigidly bolted to the steel deck and to the framework of the ship in such manner as to distribute the strain over a larger area. The clips and clip circles of the 8-inch and 6-inch carriage should be made of steel. The clips should have larger bearing surfaces, and should be shaped to fit the circle. The circle should have double flanges, and be bolted (not riveted) on each flange to the steel deck. There should be no appreciable play between the clips and the circles. All bolts used in the battery fittings should have the nuts locked. “The clip rail of the tower mount should be altered to fit the mount. This change will make the compressors effective, and allow the guns to be used with safety. The port-sills should be replaced by heavier sills, made of the best quality of malleable cast-steel. The plan of testing the hull, guns, and fittings of the _Atlanta_ arranged by the Board contemplated a more extended use of the main battery, but the weakness developed in the port-sills and in the sockets of the 8-inch carriages rendered further firing inadvisable.” Whatever conclusion may be drawn from this report, there is one fact which may serve as an important corollary. In the latest drills of the ships on the North Atlantic station, the _Atlanta_ won the champion pennant for the best gunnery practice, and this with guns and carriages which were said to be completely disabled. The safe employment of high explosives for war purposes is looked upon by many as a solution of certain vexed problems, and much time and money have been given to the subject. From the nitro-glycerine products there has been a loudly heralded advance to melinite and roborite, of which the great things expected have not yet been realized. Among the most promising attempts to use dynamite in a projectile is that made with the pneumatic gun, perfected by Lieutenant Zalinski, of the U. S. Artillery, who has courteously furnished the following description of the system: “The pneumatic dynamite torpedo gun is a weapon which has been evolved for the purpose of projecting with safety and accuracy very large charges of the high explosives. While a gun in name and form, it is practically a torpedo-projecting machine, the propelling force used being compressed air. The use of the compressed air gives uniformity and complete control of pressures and total absence of heat. This insures entire absence of violent initial shocks from the propelling force; it also eliminates danger of increasing the normal sensitiveness of the high explosives by heating while resting in the bore of the gun. The ability to reproduce, time after time, absolutely the same pressure necessarily carries with it great accuracy of fire. The torpedo shell thrown by the gun is essentially arrow-like, and is very light and compact compared to the weight of charge thrown. This is a matter of no little importance on shipboard, as a very much larger number can therefore be carried for a given weight and storage room. The torpedoes projected by this machine have a twofold field of action when acting against ships: first, the over-water hull, second, the under-water hull. “The shell is exploded by an electrical fuse. This is brought into action if striking the over-water hull an instant _before_ full impact. If the shell misses the over-water hull and enters the water, explosion is produced _after_ the shell is thoroughly buried, thus obtaining the fullest tamping effect of the water. The delayed action of the fuse can be controlled so as to cause the shell to go to the bottom before explosion ensues. This is needed at times when the torpedo shell is used for counter-mining a system of submerged stationary torpedo defences. “Experiments against iron plates have shown that it is essential to have the initial point of explosion at the rear of the shell. When explosion takes place by simple impact from the front end, the injury to the plates is actually less than when a blank shell is used. “For these reasons the fuse has been arranged so that the initial point of explosion is at the _rear_ of the shell. No attempt has been made to make a shell which can perforate armor before explosion. To do so would involve thickening the walls to such an extent as to materially reduce the weight of the charge carried. Besides that, it is very doubtful whether a shell fully charged with gunpowder can perforate any considerable thickness of armor without previously exploding its bursting charge. Much more will this be the case where the bursting charge is one of the more sensitive high explosives. “The pneumatic torpedo-gun system has various fields of usefulness as an auxiliary war appliance. Among these are the following: “1st. On swift-moving torpedo-boats; 2d. On larger war-vessels, for general use and for defence against surface and submarine torpedo-boats; 3d. In land defences; 4th. For use in the approaches during land sieges. “Torpedo-boats carrying the pneumatic guns can commence effective operations at the range of at least one mile, as compared to not more than three hundred yards of the boats carrying the Whitehead torpedoes. Their torpedo shell cannot be stopped by netting, as is the case with the latter. The charges which can be thrown are also much greater. The guns to be carried on the pneumatic dynamite-gun cruiser now building for the United States government will throw shell charged with 200 and 400 pounds of explosive gelatine. These guns can be fired at the rate of one in two minutes, and indeed even more rapidly if required. “In the defence of a man-of-war no other means can as effectually stop the advance either of submarine boats or submerged movable torpedoes. This is due to the ability to explode the large charges when the shells are well submerged. Their radius of action will be so great as to avoid the necessity of making absolute hits. The chances of stopping the attack are thereby very much increased. “A tube of large calibre can be fixed in the bow, so as to be of use when advancing to the attack with the ram. An 18-inch shell, containing 1000 pounds of explosive gelatine, can be thrown 500 yards in advance of the ship, and that, too, without danger of running into the explosion of its own petard, as would be the case in ejecting directly ahead ordinary torpedoes. This will be made more clear by the statement of the relative speed of the two classes. The pneumatic-gun torpedo has a mean velocity of 400 knots for a range of one mile, as compared to 25 knots for a range of 200 yards of the Whitehead torpedo. Furthermore, there is no danger of the shell turning back, as is sometimes the case with the latter. “The opportunities of making an effective hit will be much greater with the torpedo shell than with the ram; it will be easier to point the vessel fairly at the enemy’s broadside when at the range of five hundred yards than to bring the ram in absolute contact with the enemy’s side. The gun-tubes used are very thin (not exceeding three-quarters of an inch in thickness), and may be of sections of any convenient length. The other portions of the supporting truss, reservoirs, etc., are also of comparatively light weight. They could be of large calibres, and the destructive effects producible by large charges of high explosives will doubtless have a demoralizing effect upon the defence.” Upon September 20th of this year a public trial was successfully made with the gun, the target being the condemned coast survey schooner _Silliman_. After firing two shots to verify the range, the gun was loaded with a projectile which was five and a half feet in length, contained fifty-five pounds of explosive gelatine, and was fired under an air pressure of 607 pounds. The torpedo rushed from the muzzle of the tube with a loud report; in thirteen seconds it plunged into the water close under the starboard quarter of the _Silliman_, and exploding almost instantly, threw a great volume of water one hundred and fifty feet into the air. For a moment the schooner was hidden from view, but when the mist cleared away it was found that her main-mast had toppled over the side. At a distance this seemed to be all the damage inflicted, but a closer inspection showed that all the wood-ends on deck had been loosened, that the cabin fittings had been thoroughly shaken up, and that water was running into the hold. Soon afterwards a fourth shot was fired. This landed very close to the starboard side of the vessel, and on explosion seemed to lift the _Silliman_ out of the water. The hull was very badly shattered; the water-tank, which had been firmly fastened to the schooner’s bottom, was blown up through the deck and floated on the wreckage, and the stump of the main-mast was capsized. The bow was held above water by barrel buoys, and the fore-mast, which had heeled over to an angle of forty-five degrees, was sustained by the steel rigging that had become entangled in the pieces of wood floating to windward. MACHINE AND RAPID-FIRE GUNS. Of the machine guns, the Gatling, Gardner, Nordenfeldt, and Maxim systems are the best known. The adoption of the Accles feed in the Gatling eliminates largely the liability of cartridge jams, and increases the rapidity of fire at all angles to twelve hundred shots per minute; when this rapid delivery of fire is not needed, Bruce’s slower feed may be substituted. The Gardner gun is an effective weapon, but it has less rapidity of fire and smaller range of vertical train than the Gatling. The Nordenfeldt rifle-calibre gun has not obtained the prominence of the others, and the Maxim, in which the energy of recoil is ingeniously applied to the work of loading and firing, is growing in favor. The Hotchkiss revolving cannon was a wonderful step—the 37, 47, and 53 millimetre calibres firing 1 pound, 2½ pound, and 3½ pound explosive projectiles, with muzzle velocities of about 1400 feet per second. “The heavier nature of revolving cannon,” declares Commander Folger, United States Navy, “proved somewhat unwieldy, and the change to the single barrel of increased length, and using a heavier powder charge, was a natural one, and in keeping with the growing ballistic power of large guns. Though no longer denominated machine guns, the term now being generally applied to a cluster of barrels, the rapid-fire guns are a direct outgrowth of the larger calibres of machine guns, and are classed with them as secondary battery arms. There are now in the service of all the great military powers rapid-firing guns of 47 and 57 millimetre calibre, firing respectively explosive shells of 3 pounds and 6 pounds weight, at muzzle velocity of about 1900 feet per second. This will give with the 6-pound gun a range of about 2½ miles at 10 degrees elevation. These guns will deliver, under favorable circumstances, perhaps ten aimed rounds per minute, and the shells perforating the sides of an unarmored vessel, and bursting, after passing through into, say, twenty-five fragments, each with energy sufficient to kill a man, we have here a weapon of unequalled destructive capacity. It is beyond question that the conditions of combat between ships and forts are definitely changed by the advent of these guns. Even armored vessels with covered batteries are at a disadvantage, as a hail of missiles will seek the gun-ports and conning-towers wherever an enemy, from the nature of circumstances, takes close quarters. Experiment abroad has also demonstrated that the projecting chase (forward body) of a large gun is extremely vulnerable, and liable to injury from the fire of the larger rapid-firing pieces. “This system, which is just now so important an adjunct to the main battery of ships of war, is of but recent development. The first order received for a weapon of this kind by the Hotchkiss firm came from the United States, and the guns now mounted in the new ships _Boston_, _Atlanta_, and _Dolphin_ were delivered under it. Three calibres were obtained, _viz._, the 6, 3, and 1 pounder, as they are known in the United States navy, their usual names in other countries being the 57, 47, and 37 millimetre guns. Since their