466 



GUNBOAT 



GUN-COTTON 



commercial success. The standard size of the 

 modern shot-gun is 12 bore i.e. twelve spherical 

 leaden bullets of the same diameter as the interior of 

 the barrel will weigh 1 Ib. avoir. ; formerly 16 and 20 

 bores were much in vogue, and 16 bores are still very 

 common in Germany ; 10 bores are much used in 

 North America ; 8 and 4 bores are used only for 

 wild-fowling; and punt-guns, guns of from 1-inch 

 to 3-inch bore fitted into shooting punts, are 

 employed for firing from \ Ib. to 4 Ib. of shot at a 

 time into flocks of sea-fowl on the coast or in tidal 

 estuaries. 



With the exception of the punt-guns, which 

 require special mechanism, guns of all bores are 

 made upon the same principle of breech -loading, 

 and nearly all are more or less choked i.e. the 

 diameter of the barrel is suddenly lessened near 

 the muzzle, forming a cone which causes the pellets 

 of the charge to My from the gun more compactly 

 and at an increased velocity. Such is the perfec- 

 tion to which the boring of shot-guns has been 

 brought that a 7-lb. gun may now be expected to 

 send on an average 220 pellets of a charge contain- 

 ing 305 pellets into a circle 30 inches in diameter 

 ( or 60 into a 10-inch square ) at 40 yards distance, 

 the pellets having an average velocity at the 

 muzzle of 840 feet per second, and a striking force 

 at impact ( 40 yards ) of 1 '90 oz. 



Shot-guns are now built very much lighter than 

 when breech-loaders first came into general use 

 ( 1865 ) ; shorter barrels are used without loss of 

 shooting power or appreciable increase in the 

 volume of the recoil. Smokeless explosives are in 

 general use all the world over for shot-guns, and 

 the results of the slightest variation in the charge or 

 quality of the powder, or in the size and quantity 

 of the shot, can be ascertained with the greatest 

 scientific accuracy, by means of special instruments 

 found in all leading gun-manufactories. Shot-gun 

 manufacture is a mechanical science as well as a 

 handicraft, arid the finest productions of the most 

 renowned gun-makers will always command 50 or 

 even higher prices. Cheap ill-made, ill-fitted, ill- 

 regulated guns, shaped by machinery, or still more 

 roughly by hand labour, constitute the shot-gun of 

 commerce, and their value fluctuates with the 

 price of material. The shot-gun of the best class 

 is now so highly perfected that a new departure, 

 whether towards the development of the killing 

 powers of the weapon or elaboration of its mechan- 

 ism, is undesirable, and, until some radical change 

 in the composition of explosives, or the method of 

 using shot-guns, takes place, no noteworthy im- 

 provement upon the existing type of gun can be 

 expected. 



See the articles GUNPOWDER, FIREARMS, BREECH- 

 LOADING, CANNON, MUSKET, RIFLES, MACHINE GUNS, 

 &c. ; Greener's Gun and its Development ( 1881 ), and his 

 Modern Shot Guns ( 1888 ) ; Hawker's Guns and Shooting 

 Instructions (1844) ; Shooting, by Lord Walsingham and 

 bir R. Payne-Gallwey (Badminton Lib. 1886); Payne- 

 Gallwey's The Fowler in Ireland (1882); Walsh's 

 Modern Sportsman's Gun and Rifle ( 2 vols. 1883-84 ) ; 

 General Norton's American Inventions and Improve- 

 ments in Breech-loading, Small Arms, Heavy Ordnance, 

 Machine Guns, Magazine Arms, &c. ( New York, 1889 ). 



Gunboat, a small boat or vessel armed with 

 one or more guns of heavy calibre. From its small 

 dimensions, it is capable of running close inshore 

 or up rivers, and from the same cause it has 

 little chance of being hit by a larger vessel at the 

 long range which the carrying power of its guns 

 enables it to maintain. At the outbreak of the 

 Russian war, a large squadron of them was hastily 

 constructed for the British navy for the first time. 

 Their tonnage was small ; and their armament 

 usually consisted of one 8-inch gun and one 100- 

 pounder Armstrong gun. Gunboats in their more 



modern form (like the Staunch) are small mastless. 

 vessels mounting one large gun in the bow, and 

 propelled by an engine with single or twin screws. 

 The gun is pointed by means of the helm or the 

 screws, and the gunboat is in fact a floating gun- 

 carriage. In the British navy these gunboats carry 

 an armour-piercing gun of 18 tons, on a draught of 

 only 4 feet. But they have been designed to carry 

 35-ton guns, or heavier. In 1890 there were on the 

 British Navy List 114 of these vessels, of which 

 43 were called third class, and are intended for 

 coast defence. The largest size of the first-class 

 gunboats then in commission or building were of 

 735 tons and 4500 horse-power. At the beginning 

 of the century the United States had over 250 of 

 these vessels ; but the ' gunboat system ' was soon 

 abandoned. In 1899 the United States navy pos- 

 sessed seventeen gunboats of from 900 to 1400 tons, 

 armed with 4-inch quick-fire guns and light second- 

 ary batteries. They are mainly unarmoured, though 

 some have a light protective deck. Most continental 

 navies are provided with gunboats of various size 

 and construction. 



Gun-carriage is a most important adjunct to- 

 every piece of ordnance. It requires to be of great 

 strength in order to resist the shock of discharge, 

 and, in the case of a field-gun carriage, to bear an 

 enormous strain in passing at a rapid pace over 

 broken, uneven, or rocky ground without being 

 unduly heavy or wanting in mobility. A large 

 department, fitted with splendid machinery, in the 

 Royal Arsenal at Woolwich, called the Royal Car- 

 riage Department, is charged with this branch of 

 manufacture for the British service, whether naval 

 or military. See CANNON for plates showing 

 several of the numerous patterns, and also MON- 

 CRIEFF PITS. 



Gun-COtton. There are a very large number of 

 explosive nitro-compounds which may be divided 

 into two main classes viz. ( 1 ) Those containing 

 Nitro-glycerine (q.v. ), in which is included the 

 great dynamite class, and (2) those not containing 

 nitro-glycerine. Gun-cotton is an explosive nitro- 

 compound of the latter class, and is by far the 

 most important of the class. 



So long ago as 1832 it was discovered by Bracon- 

 not that woody fibre and similar substances could 

 be converted into highly combustible bodies by the 

 action of concentrated nitric acid ; six years later 

 Pelouze extended this discovery to cotton and 

 other organic substances ; he was followed by 

 Dumas, who treated paper in a similar way, and 

 he proposed to make cartridges with paper so- 

 treated, the idea being that no residue would be left 

 in the barrel after firing such cartridges. But no- 

 practical result followed these discoveries until in 

 1845 Schonbein, a German chemist, having hit 

 upon the proper mode of treating cotton with 

 nitric and sulphuric acids, announced the discovery 

 of gun-cotton, which he proposed as a substitute for 

 gunpowder. He claimed for it that the advantage 

 it had over gunpowder was that it burned with- 

 out leaving any residue, and consequently without 

 smoke. He prepared it by immersing carded 

 cotton wool in a mixture of nitric and sulphuric 

 acids, and the equation for its formation may be 

 stated thus : 



Cellulose. Nitric Acid. 



Bi-nitrated Cellulose 

 or Gun-cotton. 



Water. 



C 6 H 10 5 + 3(H,N0 3 ) = C 6 H 7 2 >3(N0 3 ) + 3(H a O). 



It will be observed that no mention is made of sul- 

 phuric acid in this equation, the presence of which 

 is, however, essential in the production of gun- 

 cotton, for although it takes no active chemical 

 part in the action, it absorbs the water which is- 

 formed by the chemical transformation, and thus- 



