48 
MINUTES OF PROCEEDINGS OF 
them better than any other that has yet been tried, all that witnessed the 
experiment admitted beyond question. 
Numerous modifications and alterations to meet the various conditions of 
strength and resistance necessary in different works have been drawn up since 
this experiment took place, but it seems hardly desirable or possible to 
describe them now. 
It is enough to say that the very simplicity of the principle makes it easy 
to adapt it to almost all circumstances, whether it be for the purpose of 
filling the front of a casemate, or for a small embrasure only, or for con¬ 
structing a work of iron altogether, or for covering a masonry wall. 
To all of them the principle is applicable, and it only requires to be 
treated with a little practical skill in its development. 
Trial of thick Armour . March 17, 1863. 
This experiment was made to test the resistance offered by some rolled 
armour plates, 5 Jin., 6Jin., and 7J in.thick,manufactured by Messrs John 
Brown and Co., of Sheffield. 
The plates were of the following dimensions :— 
One 13 ft. 4|- in., by 3 ft. 7 in., and in. thick. 
One 12 ft. 2f in., by 3 ft. 7^ in., and 6| in. „ 
One 11 ft. 9 in., by 3 ft. 8| in., and 7f in. „ 
They were secured by 2J-in. screw bolts, to the skin and frame of Mr 
Samuda's old target; one half of each plate had a backing of from 7 to 9 in. 
of teak, and at the back of the other half, it was left hollow for an equal 
interval between the plates and the skin. India-rubber washers were used 
under the nuts. 
The guns in position for this trial were— 
One 300-pr. Armstrong muzzle-loading shunt gun. 
One 9-in. Lynall Thomas gun. 
One 7-in. "Whitworth rifle gun. 
One 110-pr. Armstrong breech-loader. 
One 68-pr. service 95-cwt. gun. 
All were fired at a range of 200 yds. 
The first three shots (all cast-iron) were fired from the 68-pr., one shot 
struck each plate and made indents 1J in. deep in the 6J-in. and 7J-in. 
plates, and 2 in. deep in the 5 J-in. plate. 
These were followed by three shots from the 110-pr., also of cast-iron; 
the indent upon the 5J-in. plate was 1*9 in. deep, that upon the 6J was 
2*05 in. deep, that upon the 7J was 1*65 in. deep. There was scarcely any 
other effect visible. 
The next shot was from the Armstrong 300-pr., with a cylindrical steel 
shot weighing 301 lbs., and fired with a 45 lb. charge of powder. This 
shot had a velocity of 1295 ft. per second at 30 yards in front of the target. 
