Page:The Development of Navies During the Last Half-Century.djvu/215

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Ordnance.
181

ing of 80-ton muzzle-loading rifled ordnance in the 'Inflexible':—

Diameter of Bore Weight of Gun. Charge of Powder. Weight of Projectile. Velocity at Muzzle. Penetration of Iron at 1000 Yards.
Ins.
7
Tons.
Lbs.
30
Lbs.
110
Ft. per Sec.
1500
Ins.
7
8 9 35 180 1400 8
9 12 50 250 1400 10
10 18 70 400 1380 12
11 25 85 540 1320 13
12 35 140 700 1400 15
12.5 38 200 800 1550 17
16 80 450 1700 1600 23

A few words must now be said about the ammunition. Experiments had shown that against armour cast-iron shot broke up like a snowball, while forged wrought-iron projectiles flattened, as if made of lead, against the hard or comparatively hard surface. In both cases the iron plates suffered little, because the energy was expended in breaking or distorting the missile. In this dilemma Captain Palliser came to the rescue with his ingenious device of hardening the front portion of a shot by chilling. The body is cast in an earthen mould, but the head is formed by a metal mould, which rapidly extracting the heat in this portion gives great hardness to the material. The result is