THE DEVELOPMENT OF ARMOUR. 
488 
Projectile. 
Striking 
velocity, 
f.s. 
Striking 
energy, 
foot tons. 
Energy per ton 
of plate, 
foot tons. 
Calculated 
perforation of 
wrought iron, 
inches. 
Relation of per¬ 
foration to 
thickness of 
plate. 
1.—Wheeler Sterling ... 
1413 
11,770 
401 
17-0 
1*13 
2.—Carpenter . 
1760 
18,260 
622.2 
23-6 
1*58 
3.—Wheeler Sterling ... 
1727 
17,570 
598-0 
22-9 
1-53 
Fig. 14 shows the effect of the first round, which penetrated 18*25 
inches without cracking the plate or breaking bolts. The shot re¬ 
bounded 100 ft. and split in two. The second shot broke up leaving 
its head embedded in the plate and breaking the plate through the 
two shot holes. The third shot broke up as shown in Fig. 16, opening 
the horizontal crack to the extent shown inFig. 15. 
While the resistance of this plate falls far short of that of the Krupp 
11*1 in. plate already given, it must be remembered that it is selected 
as (if possible) the worst of a batch supplied for service and bent to the 
required form. The plate was clearly capable of entirely defeating the 
last round with a perforation of 1 *5 times its thickness of iron and 
delivering a shock of 600 foot tons per ton of plate and this test is a 
fairly severe blow for a sample of manufacture. 
On March 24th, 1896, at Indianhead, was tested the first 5-in. 
double forged Harveyed Carnegie armour to govern supply of 350 
tons of armour to Russia. The plate entirely defeated the attack of 
five 4-in. projectiles, with striking velocities varying from 1,660 to 
1,760 f.s. These broke up with penetration not exceeding 2 inches. 
A crack was made in one corner. A 5-in. shot with 1,705 f.s. velocity 
caused a vibration which detached a fragment at the corner. The 
armour was passed as most satisfactory. The calculated perforations 
are 8 and 9^ in. of iron. The plate, therefore, defeated an attack 
equivalent to 1.85 of its thickness after repeated blows equal to 1*61 
of its thickness or established a figure of merit up to 1*85. 
Carnegie 
barbette 
15-in plate. 
5-in. Har¬ 
veyed 
plates for 
Russia. 
{To be Continued.) 
