242 
MINUTES OF PROCEEDINGS OF 
APPENDIX. No. 2. 
REPORT ON THE PRACTICE AGAINST A CARNOT WALL, CARRIED ON AT 
WOOLWICH, BY ORDER OF HIS GRACE THE MASTER-GENERAL, IN 
AUGUST, 1824. 
1. His Grace the Master-General having considered it possible that the 
walls used in the new system of fortification recommended by Carnot, and 
carried into execution in late years in different countries might be breached 
at considerable distances by fire at high angles, desired in the year 1822, 
that a profile in earth might be prepared for trial, placing a screen of the 
proper height in lieu of a wall. 
The experiment tried at Woolwich, in August, 1822, proved that this fire 
could reach very low down the wall. 
It was doubtful, however, whether the projectile would breach the wall at 
considerable distances, say four or five hundred yards, considering the small 
quantity of powder, which it was necessary to use. 
His Grace the Master-General then determined that he would continue 
the experiment, and had a wail constructed of the usual dimensions, in the 
summer of 1823. It was 21 ft. high, and 22 ft. long, of the regular thick¬ 
ness of 6 ft. at top, and of 7 ft. at bottom as recommended by Carnot, and 
had one loop-hole in the usual recess. It was further strengthened by a 
buttress of 4 ft. square at each end, so that the total length of the wall, 
including the buttresses, was 30 ft. at bottom and 28 ft. at top; the but¬ 
tresses giving it a considerable additional strength beyond the usual wall of 
Carnot's system. 
2. The wall was carefully built, and well cemented. An earthen counter¬ 
guard, of the regular thickness, and of equal height with the wall, was thrown 
up before it: the crest of the counterguard being twenty yards from the 
top of the wall. 
A mound of earth, representing the rampart of a bastion, was thrown up 
behind the wall, and was continued at the regular slope of 45 degrees, till 
its height was 4 ft. above that of the wall, but this rampart being 8 ft. lower 
than the real rampart of a bastion would have been, was on that account of 
less use in serving as a correction to the elevation of the ordnance. 
Two batteries were constructed against the wall and opened their fire, on 
the 5th August, 1824. 
They consisted of the following pieces of ordnance :— 
Eight 68-pr. carronades at 500 yds., from the crest of the counterguard. 
Three 8-in. iron howitzers at 400 „ „ „ 
Three 10-in. do 400 „ „ „ 
One hundred rounds per piece were fired in about six hours; the how¬ 
itzers firing live shells filled with powder, the carronades firing solid shot. 
