70 
MINUTES OF PROCEEDINGS OF 
Eeport No. 3765 (26/5/65). 
The Committee submit the results of the above-mentioned preliminary 
firing. 
The experiment, which was merely preliminary, consisted in firing three 
rounds from a 9*22-inch muzzle-loading gun of 12 \ tons, rifled, against the 
pier of a casemate of masonry composed of granite facing and brick backing, 
having a total thickness of 14 feet, which pier was situated between two 
embrasures, both of which were fitted with iron shields. The work had been 
executed with the greatest possible care, and in a most substantial manner ; 
the brickwork and masonry were laid in cement. 
Prom the results of the rounds fired it appears that the effect of the very 
first discharge was to destroy the cohesion of the materials forming the 
pier fired against; this was evinced by the fracture of the bed joints of the 
granite blocks from the place struck quite round to the rear of the left 
embrasure, or that furthest from the place of the blow, and by the fracture 
which extended upwards internally towards the crown of the arch of the 
casemate. These fractures were increased, and fresh ones made by the 
two subsequent shots, the fracture in the brickwork in the rear of the pier 
becoming by the third shot of a serious nature. The whole key of the 
pier being thus broken, it may safely be assumed that every successive shot 
would tell with redoubled effect on the structure, and that a few more 
rounds striking near the same place would have destroyed the pier. As it 
was, the pier was so much shaken, that to make it good again it will have 
to be taken down and rebuilt. 
It must be remembered that the security of the upper tiers of guns, so 
far as depending on any one pier, would be very much compromised, and 
the ruin of the work accelerated by the concussion of the firing supposed 
to be going on from within. A casemate, therefore, that shows such a 
result as that above described, after being hit by only three shots, two of 
which were fired with charges representing a range of 1000 yards, and 
only one at 600 yards, would be rendered untenable if struck by half a 
dozen consecutive shots delivered from a gun of equal power, and it may 
fairly be assumed that a less number striking simultaneously, or nearly so, 
would have an equally disastrous effect as regards the immediate locality 
subjected to them. Generally it maybe observed that the experiment, even 
in its present early stage, tends to prove that a thickness of 14 feet of 
combined granite and brickwork, is insufficient to hold out against the 
attacks of vessels armed with guns of similar power to the ones used on the 
18th, and that a much increased thickness of masonry (and consequently in¬ 
creased expenditure) would be necessary to enable a masonry fort to cope for 
any length of time successfully with heavily armed ironclads, supposing them 
capable of resisting the artillery of the fort. This element of the question is 
one into which the Committee are not called upon to enter. It is sufficient 
for them to remark that the whole of the shot which struck the pier would 
have passed through the side of the “Lord Warden/ 5 one of the very 
strongest vessels yet built, that effect having been produced on the 17th 
June 1864, by two steel shot of 221 lbs. fired with 30 lbs., with apparent 
ease. 
