OKI'XANCK. 



ORDNAXCE. 



brui gun (a heavy six-pounder). Shell gun* differ from shot guns in 

 being of greater calibre in projxirtion to their weigbt of met&l. The 

 bora of shell guu* is also contracted toward* the breech, thus forming 

 a chamber. The tixe of shell guns is denoted by the diameter i.f the 

 b>re in inches. Shell guns are employed for projecting shell and 

 hollow shot, and are principally for sea sen-ice. They are made of 

 iron, Guns of 12-inch diameter hare bean made, but the sizes 

 employed in the service now are the 10-inch and 8-inch guns only. 



We have subjoined n table of the dimensions and weights of the 

 principal natures of guns in use in the British service. The natures 

 and uses of carronades, howitzers, and mortars have been already 

 described under those word*. 



CoxTrcTiox or Oanxixcr Io. 



1 



I. 

 I 



- 

 - 

 - 

 I 

 I 

 1 



8 

 I 



- 

 I. 

 L 



O 

 



o 

 O 

 O 



o 

 t 



M 



o 

 



o 



(I 

 o 

 o 



6 



I 



32. pounder carronade 



>* .. 



10-inch honitzcr 



5 



13-inch mortar 

 I* 



10 ,. 

 10 ., 



8 n 



G 

 5 11 



3 11) 



' 'I 



5 ; 



4 ' 



5 4f 

 4 4 

 3 3! 



3 9 ; 



2 7J 

 2 1} 



17 

 11 

 17 

 13 

 10 



0} 

 43 

 22 

 15 

 100 

 3G 

 50 

 18 



9 



3-66 

 3-OG 

 G-25 

 558 

 5-16 

 4 52 



10 

 8 

 5-68 



13 



13 



10 



10 

 8 



CoxsTrcTiox or ODXAXC BIAS*. 



. vice ; L, Land twice ; 8 I,, both ; M Millar ; M', Monk ; (), 

 OKI. nary ; I, Intermediate between M and O beinj bored. up gunn. 



The axis of the trunnion* U at right angles to that of the gun, and 

 U usually about half their diameter below the latter axis ; but Dr. 

 Gregory, in his 'Lectures on Hunnery,' recommend* that it should 

 interned the axis of the gun, in order that the recoil of the pi.-. .- in 

 firing may act lem on the carriage. The vent U two-ninths of an in. h 



8,Sea8ertlee; L. Land service ; SI, both; M, Millar ; M', Monk ; O, Ordinary. 



in diameter, and it enters the bore at about eight-tenths of an inch 

 from the bottom of the latter. 



The diameter of the bore is called the calibre of the gnn ; this is 

 rather greater than the diameter of the phot by which the nature of 

 the gun is designated, and the difference between them is called the 

 windage. [\Vixi>.\c;i:.] 



A scale of quarter degrees is graduated on the base ring, the zero 

 line being in a plane passing through the axis of the gun and cutting 

 the exterior surface immediately above the trunnions, and the inter- 

 section of such plane with the side of the muzzle is marked by n notch 

 on the latter. These quarter-sights, as they are called, serve to give 

 the gun an elevation not exceeding three degrees ; and this is accom- 

 plished by lowering the breech till the division expressing the intended 

 elevation and the notch on the side of the muzzle are in a line with 

 the object. The axis of the gun will then be inclined to a plane 

 passing through the object and the axis of the trunnions, in 

 an angle equal to that which is indicated by the division above 

 mentioned. 



A point-blank disposition of the gun is that in which the zero notch 

 on the base ring and that on the side of the muzzle are made to 

 coincide in direction with the object, whether this line of direction be 

 or be not parallel to the horizon. But when a notch on the top of the 

 base ring and one at the top of the muzzle are made to coincide in 

 direction with the object, the gun is said to have the line of 

 deration. [GUNNERY.] The angle which the axis of i he LMIII. in thin 

 case, makes with a plane passing through the trunnions, and the object, 

 varies with the nature and construction of the gun, but is generally 

 about one degree. 



For elevations greater than three degrees a tangent scale is employed ; 

 this is a brass rod which slides up and down in a groove formed in the 

 direction of a diameter to the base-ring of the gun, and is divided into 

 quarter degrees. In using this scale the latter is drawn up till the 

 graduation expressing the intended elevation is at the surface of the 

 base-ring ; then the breech of the gun is lowered till a notch at the top 

 of the scale and that at the top of the niuz/le are in a line with the 

 object. The axis of the gun (allowance being made for the difference 

 between the semidiameters of the base-ring and muzzle [DISTANT] ) is 

 then inclined to a plane passing through the trunnions and the i.'.j.vt 

 in an angle indicated by the said graduation. 



It was considered advisable at one time to convert a number of 

 heavy guns into a description of shell gun by boring or rmuiinii //, 

 that is, re-boring and enlarging the bore of various guns in the ser- 

 vice to the next higher calibre : thus, 24 -pounders were bored up into 

 32-pounders. The practice was first recommended by Colonel Pnixhans, 

 in France. 



The application of locks to naval ordnance was introduced by Sir 

 Charles Douglas (captain of the fleet to Admiral Rodney in the action 

 of 1782), and their efficiency was soon fully recognised. At first the 

 locks were mode with one flint only, and in the event of this becoming 

 unserviceable the loss of time attending the fixing a fresh flint was 

 found to be go great, that instead of renewing the flint, recourse was 

 generally then had to the hntstock or port-fire. But this defe. t MM 

 removed by the construction of a lock which carried two flinU, so 

 disposed, that on the failure of one, by simply turning the nut, the 

 other might be brought into use. This improvement was made in 1818, 

 by Major-General Sir Howard Douglas ; it was immediately introduced 

 in the British navy, and was afterwards adopted in the land-service 

 artillery. This was followed soon afterwards by the introduction t 

 the percussion tube into the navy and heavy artillery, and the friction 

 i -field artillery, and indeed for heavy artillery also often v. h. n 

 on shore. The percussion tube is fired by a hammer which is made to 



