464 
THE DEVELOPMENT OF ARMOUR. 
In 1893, several trials of 
thick plates of Harveyed 
armour proved that the pro¬ 
cess was capable of impart¬ 
ing to thick armour a consider¬ 
able measure of, though not the 
full advantage given by it to 
thinner plates. In this year 
also, the great tpughness im¬ 
parted by nickel was illus¬ 
trated in American plate trials. 
Harte ed ^*£* ^ S ^°WS the sketch of 
i4.in!p T iate a Harveyed nickel steel plate, 
attacked by 9 ft. x 7 ft. x 14 in. after 
io-xn. shot. a f^ ac k by 10 in. Holtzer pro¬ 
jectiles, each weighing 500 lbs. 
The striking velocities, 
energies and calculated per¬ 
forations are shown in the 
following table, TresiddeFs 
formula being used for 
velocities over 1,580 f.s., that 
is for the last three rounds :— 
i 
Fig . 1. 
Round. 
Striking 
velocity 
feet seconds. 
Total energy, 
foot, tons. 
Energy, 
per ton of plate, 
foot, tons. 
Calculated Perforation, 
inches, 
iron. steel. 
No. 1 
1472 
7513 
469*6 
15-8 
12-7 
f? 2 
1859 
11,990 
749-4 
21-5 
17-2 
. 3 
1959 
13,300 
831-3 
23-1 
18.5 
„ 4 
2059 
14,700 
918-8 
25-0 
20-0 
The importance of this trial consists in the fact that the plate was 
much thicker than those previously tried. It was broken up but not 
perforated and no bolts were severed. The projectiles in every case 
broke up, the maximum perforation of the embedded head being 
estimated at 11 inches. 
On July 11th, at Indianhead, two nickel steel plates with un¬ 
hardened faces shown below, were tested 1 , which exhibited the tough- 
1893 ness characteristic of such unhardened nickel plates. Fig. 2 shows a 
Carnegie Carnegie plate for the side armour of the Monadnock, 9 ft. 7 in. x 
9 l for Plate ^ ft* in. x 9 in. and weighing about 10 tons. It was attacked by 
MonadnocJc three 8-in. forged Holtzer shot, each weighing 250 lbs., with 1,400, 
1,683 and 1,543 f.s. velocity successively. The second shot with a 
calculated perforation of 14*7 of iron or 11’8-in. of steel, perforated the 
1 Witnessed by the writer and described in the Engineer of July 28th, 1893. 
