THE DEVELOPMENT OF ARMOUR. 
517 
one ton weight, after being subjected to the service test on supply— 
that is, an attack by three Palliser 5-in. projectiles each weighing 
50 lbs., with striking velocities of 1,406, 1,750, and 1.750 ft.-secs. 
The calculated perforation of each of the last two rounds is 8 8 in. of 
iron, and the shock per ton about 905’3 ft.-tons. The shot are, on 
one hand, brittle, but, on the other, of calibre exceeding the thickness 
of the plate. On the whole the test is much less severe than that to 
which 6-in. plates are subjected, and it may be seen that the plate, 
which is apparently a very good one, is scarcely bruised by it. 
In July Messrs Tickers had a most successful trial of a 4-in. special 
nickel plate on the Nettle . The test and the defeat of the projectiles 
was the same, and the results nearly the same, as shown above in the 
case of the Cammell plate. 
Messrs. Brown made an important trial as to the behaviour of a 
rough worked face and the effect of “ lap,” or fold, on a face struck 
by shot. A 6-in. plate was machined on one face and divided, one 
half subsequently having the machined face treated, and the other the 
rough face, across which was a lap. Both resisted the usual attack of 
five 6-inch projectiles, striking with a velocity of 1,960 ft.-secs., with¬ 
out serious cracking. It appeared, however, that one shot, striking 
exactly on the lap, got more nearly through than any of the others on 
either plate, including one striking a spot one inch from the lap ; con¬ 
sequently this trial seems to indicate that machining is waste of work, 
and that a lap produces no effect unless the shot strikes exactly on it. 
The photographs herewith show results of a trial of an experimental 
plate made on Krupp^s process. The special points of interest are, 
first, that Krupp^s process should be adopted in the very home of the 
Harvey process; secondly, the severity of the test; and thirdly, the 
comparative action of ordinary uncapped and of capped shots. 
The trial took place on July 13th last at Indianhead by the United 
No. of round. 
Striking velocity. 
j 
Striking energy, 
Calculated perforation 
through iron by 
Tresidder’s formu.a. 
d . 
•S 2 
+* 5 
= |° 
o S 
•rt <d 
w|| 
•S3 
o 
Results. 
Ft -sec. 
Ft.-tons 
Inches. 
1 
2021 
2832 
14'1 
2'35 
Projectile smashed with about 2‘5-in pe etration. 
2 
2237 
3470 
16'3 
2'72 
,, ., with 5-in. estimated penet ation. 
h 
2350 
3830 
17-7 
2'95 
Pe forated, but remained in backing and broke up. 
4 
(capped) 
1984 
2730 
13*9 
231 
Perforated plate and backing and broke i.p. 
Vickers 
Plate. 
Messrs. 
Brown’s 
experiment 
Carnegie 
Krupp 
armour. 
