Page:EB1911 - Volume 20.djvu/237

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HISTORY AND CONSTRUCTION]

ORDNANCE

209

guns are much stronger. This is an obvious advantage, but an equally solid one is the fact that owing to the greater weight of the home-made weapon the recoil energy is less and consequently the mounting can be made of a lighter pattern. Besides, the weight of the gun is so disposed as to bring its centre of gravity as near the breech end as possible; by this means the radius of the gun house is reduced to the smallest dimension and, in consequence, there is a great saving of weight of armour. The extra weight of the gun is therefore more than compensated for.

Fig. 54.—Metallic Cartridge Case.

Table II.—*Names and Weights of English Cannon*, *1574*
Names.	Weight.	Diameter of Bore.	Diameter of Shot.	Weight of Shot.	Weight of Charge. Serpentine.	Scores of Paces at point-blank.
	℔	in.	in.	℔	℔
Robinet	200	11/4	1	1	1/2	. .
Falconet	500	2	13/4	2	11/4	14
Falcon	800	23/4	21/2	21/2	21/2	16
Minion	1100	31/4	3	41/2	41/2	17
Sacre	1500	31/2	31/2	5	5	18
Demi-Culverin	2500	41/4	4	9	9	20
Culverin	4000	51/4	5	18	18	25
Demi-Cannon	6000	61/2	61/4	30	28	28
Cannon	7000	73/4	71/2	60	40	20
Eliza-Cannon	8000	8	73/4	63	42	20
Basiliske	9000	83/4	81/2	60	60	21

Table III.
Gun.	Weight of Charge.	Weight of Shot.	Muzzle Velocity.
	℔.	℔.	f.s.
27-pr. 66 cwt.	13·125	27	1517
131/2 pr. 37·5 cwt.	6·562	13·5	1618
63/4 pr. 20 cwt.	4·922	6·75	1696
33/8 pr. 11 cwt.	2·469	3·375	1720

Table IV.—*British Smooth Bore Guns*, *1860*.
Official Designation of Gun.		Calibre.	Weight of Gun.	Weight of Charge.	Weight of Projectile.	Muzzle Velocity.	Muzzle Energy.
		In.	Tons.	℔.	℔.	Ft. Secs.	Ft. Tons.
Cast Iron. $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	10 in. 87 cwt.	10	4·35	12	88·31	1292	1022
	68 pr. 95 „	8·12	4·75	16	66·25	1579	1145
	8 in. 65 „	8·05	3·22	10	49·875	1464	742
	32 pr. 58 „	6·375	2·9	10	31·375	1690	621
	24 „ 50 „	5·823	2·5	8	23·5	1720	482
	18 „ 38 „	5·292	1·9	6	17·69	1690	350
Bro- nze. $\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	12 „ 18 „	4·623	0·9	4	12·66	1769	275
	9 „ 13 „	4·20	0·65	2·5	9·36	1614	169
	6 „ 6 „	3·668	0·3	1·5	6·23	1484	95

Table V.—*British B.L. Ordnance*, *1860. Armstrong System.*
Official Designation of Gun.	Calibre.	Weight of Gun.	Weight of Charge.	Weight of Projectile.	Muzzle Velocity.	Muzzle Energy.
	In.	Tons.	℔.	℔.	Ft. Secs.	Ft. Tons.
100 pr.	7	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ 4·1 3·6 $\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$ *	12	103·75	1166	978
40 „	4·75	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ 1·75 1·6 $\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$ *	5	41·5	${\Big \{}$ 1164 1134	390 370
20 „	3·75	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$ 0·8 0·65 $\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$ *	2·5	21·22	${\Big \{}$ 1114 997	162 146
12 „	3·0	0·425		11·56	1184	112
9 „	3·0	0·3	1·125	9·0	1141	81
6 „	2·5	0·175	0·75	6·0	946	37

At a later date the velocities of these guns were altered. * Two patterns were in existence.

Until late into the 16th century the calibres of the guns were not regulated with a view to the interchangeability of shot. In the following century ordnance was divided into classes, but even then, owing no doubt to manufacturing difficulties, there was no fixed size for the bore. The Tables II.-VII. give some idea of the size and weight of these pieces.

Table II. is taken from Cleveland’s Notes, but corrected from “An Old Table of Ordnance” (Proc. R.A.I., vol. xxviii. p. 365); the last column gives the range in scores of paces at point-blank, a term used in those days to denote the first part of the trajectory which was supposed to be a straight line. Later the point-blank range was that distance from the gun on its carriage to the first graze of the shot on the horizontal plane when the axis of the gun was placed horizontal; this depended on the height of the gun above the ground plane, but it was the only method of determining the relative power of these early guns.

In power, smooth-bore guns in Europe did not differ very much from each other, and it may be taken for granted that the progress made since has been much the same in all.

D’Antoni, in his Treatise of Fire Arms (translated by Captain Thomson, R.A.), gives particulars of Italian guns of about 1746, which are shown in Table III.

It will be seen that the velocities given in Table III. are not inferior to those obtained from guns actually in use in 1860 (see Table IV.). They were considerably higher than those for elongated rifled projectiles (Table V.) for many years after their introduction; the last-named, however, during flight only lost their velocity slowly, while the spherical shot lost their velocity so rapidly that at 2000 yds. range only about one-third of the initial velocity was retained.