SHOUT NOTES ON PUOEESSIONAL SUBJECTS. 
57 
49. Iron Plate Experiments. Experiments have recently been made at 
Shoeburyness to test the power of resistance, to Palliser shot, of unbacked iron 
plates, 10 inches in thickness, in comparison with that of two 5-inch plates bolted 
together. 
Eor these experiments a 9-inch M.L.B. gun of 12 tons was used, at 70 yards 
range. 
One 10-inch plate was manufactured by Messrs Cammell, of the Cyclops Iron 
and SteelWorks, Sheffield; the other by Sir John Brown & Co., of the Atlas 
Works, Sheffield, being a sample of those intended for the “ Monarch.” 
Messrs CammelTs plate successfully resisted the penetration of two Palliser shot 
of 248 lbs. weight, each, fired with a 43 lbs. charge, but the official report states that 
“ the first round (which was fired with a 25 lbs. charge), caused the 10-inch plate 
to separate into two 5-inch plates, and the rest of the experiment was prac¬ 
tically at a compound structure of two 5-inch plates.” 
The “ Atlas ” plate was first tested at Portsmouth with nine cast-iron shot 
fired from a 68-pr. S.B. gun, 16 lbs. charge at 30 feet range, and was reported 
Al quality. It was subsequently removed to Shoeburyness, but was completely 
penetrated by a Palliser shot of 248 lbs. weight fired with a 43 lbs. charge. The 
minute on the experiment states that these results prove— 
(1) That the 9-inch rifled M.L. gun is capable of completely perforating a 
10-inch solid plate at 70 yards, when fired with the battering charge (43 lbs.) and 
Palliser shot. 
(2) That Palliser projectiles can easily perforate plates thicker than their own 
diameter, with battering charges. 
(3) That, although it would be premature on the result of one experiment to 
give a final opinion, it appears probable that a 10-inch solid plate offers, as now 
made, little if any more resistance than two plates of 5-inch bolted together. 
In an experiment which was made at Shoeburyness in November, 1867, it was 
ascertained that two 5-inch plates bolted together will resist the penetration of a 
Palliser shot of the above weight fired from the 9-inch B. gun at 70 yards, with 
a 37 lbs. charge, but are penetrated when a 43 lbs. charge is used; and the 
following table gives the comparative results of the three experiments:—* 
Experiment. 
Target. 
Charge. 
Penetration. 
No* 
lbs. 
inch. 
1 
Two 5" plates bolted together .. 
25 
5*5 
2 
Cyclops 10" plate ... 
n 
5-55 
3 
Atlas 10" plate.... 
// 
6-5 
1 
37 
13-0 
2 
f .......... ] 
a 
8-6* 
3 
S l 
u 
1 
1 r 
43 
total 
2 
t ..3 
a 
13-9 
3 
5 l 
// 
total 
It will at once be seen that the results of these experiments cannot be taken as 
conclusive regarding the relative value of 10 inches of iron when used in one thick¬ 
ness, or in two 5-inch plates, but a few remarks may be made on the absolute results 
obtained. And first it may require explanation how 10 inches of iron can be 
penetrated to a depth of 13 inches, as shewn in the table, unless totally pene¬ 
trated. The reason is that the 5-inch plates being merely in contact, part of the 
work of the projectile is used in forcing the plates asunder, and they become 
separated and bulged. Thus, whilst total penetration is prevented, the penetration 
and bulge is of a larger amount than the entire thickness of the plates. 
9 
* Shot badly chilled* 
