ARMOUR-PIERCING PROJECTILES. 
487 
The same-seems to hold good when the fire is oblique. A compound 
10-in. plate was broken up by six blows on 48 sq. ft., amounting to an 
average of 554 ft. tons per sq. ft., whilst a 12-in. iron plate was capable 
of taking on a surface of 128 sq. ft. an average of 992 ft. tons per sq. ft, 
delivered in 29 blows. 
From experiments with steel and chilled iron projectiles a diagram 
is given in the report showing the penetrative powers of 9-in. and 
13-pr. R.M.L. guns, and of the 8-in. and 6-in. Armstrong guns, when 
fired against unbacked wrought-iron plates. The following charges 
and projectiles were employed :— 
Gun. Charge. Projectile. 
9-in. MX. 75 lbs. P 3 . 268 lbs. 
8 „ . 90 lbs. P. 182-5 lbs. 
6-in. B.L. 33 „ .. 80lbs. 
13-pr. M.L. 34lbs. R.L.G.* 1 H* lbs- 
C lu i^ " 
The 9-in, gun can penetrate 12 ins. at the muzzle. 
9T ins. at 1800 yds, 
7*25 „ 3700 „ 
6*4 „ 5440 „ 
4*8 „ 10000 „ 
The 8-in. gun (Armstrong) 14*8 
10-8 
9-25 
6*9 
4*5 
u the muzzle. 
„ 2000 yds. 
„ 2900 „ 
a 5100 „ 
a 10400 n 
... 10*8 a the muzzle. 
6-85 „ 1500 yds. 
6*2 „ 2300 u 
4*43 „ 4700 „ 
2*8 „ 9700 a 
Heavy projectile. 
The 6-in. (Armstrong) 
The 13-pr. MX. 
4*75 ins. at muzzle 
3-27 „ 900 yds, 
2-9 „ 1300 „ 
1*93 i, 3380 „ 
1*10 « 7183 . 
Light projectile. 
4*5 ins. at muzzle. 
2*9 „ 900 yds, 
2'6 n 1200 // 
1*75 /, 2830 „ 
0-95 „ 5800 „ 
Experiments were made with a view of ascertaining whether it was 
feasible to employ bursting charges of wet gun-cotton in armour- 
piercing shells, the charges being exploded by a delay-action percus¬ 
sion fuze screwed into the base of the shell, and containing a 2-oz. dry 
gun-cotton primer. 
Several fuzes were tried differing chiefly in strength and size of 
slowing chamber. All more or less resembled the delay-action fuze, 
recently introduced for the base of 64-pr. battering shell, in their 
