238 
MINUTES OF PROCEEDINGS OF 
Experiment 2.— 17th September, 1860. 
Eour iron 12-prs. rifled, with the same charge and projectile made an 
opening 10 ft. wide and 6 ft. high in a brick wall 4 ft. thick at 1105 yds. 
The expenditure of ammunition was 64 rounds (16 per gun), but only 47 
shells took effect. The profile of the work is shewn in Eig. 2. 
The wall was 11 ft. high, of which 1| foot was covered, and the whole 
was hidden from view by a parapet 13 ft. 6 in. high, at a distance of 105 ft.; 
requiring slightly larger angles of descent than in the first experiment, but 
still not exceeding 6°. 
Experiment 3.—17th September, 1860. 
The two brass and four iron 12-prs. of the preceding experiments were 
employed to breach a wall at 694 yds. distance. It was 7 ft. thick and 14 ft. 
high, supported at intervals by counterforts 4 ft. thick, and covered from 
view by the crest of a glacis at 135 ft. distance, as shewn in Eig. 3. 
Eig. 3. 
In this case it was not even necessary to diminish the service charge, and a 
complete breach was effected with an expenditure of 132 shells, the descend¬ 
ing angle being under 3°. 
If we compare the above profiles with the profile of the Carnot wall 
breached at Woolwich in 1824, it will be seen that they prove but little as to 
the capabilities of rifled guns for the service under consideration. The walls 
were slighter than will often be met with, the great distance and the slight 
relief of the covering works permitted the employment of charges and 
angles of descent which deprive the problem of all practical difficulty. 
So far as they go however, they concur with what has been advanced 
above, to shew that caponnieres and concealed or sunken escarps derive no 
additional value in fortification from the introduction of rifled guns, which 
are quite as capable of breaching them as the smooth-bored ordnance 
employed so successfully for that purpose in 1823, and will do it under 
great advantages from their greater uniformity of range and the larger 
bursting charge of the shells. 
