440 
MINUTES OF PROCEEDINGS OF 
BREACHING BY INDIRECT EIRE. 
BY 
COLONEL H. II. MAXWELL, R.A. 
SUPERINTENDENT, COSSIPORE GUN FOUNDRY. 
The first instance on record, to my knowledge, of breaching by 
bigfi-angle fire is that at Woolwich in the years 1822 to 1824,* when 
experiments were carried on under the then Master-General of the 
Ordnance, the Duke of Wellington, to determine whether it was possible 
to breach walls protected by earthen counterguards, as proposed by 
Carnot in his “ System of Defence,” by firing over the crest of such 
counterguards. The inner edge of the top of the counterguard was 
31 ft. from the face of the wall; the height of the crest of the counter¬ 
guard was 24 ft., and the point intended to be struck was 12 ft. above 
the level of the ground. 
Fig. l. 
The ranges to the interior crest were 500 yds. As a rough approxi¬ 
mation, the angle of incidence of the projectile would be that whose 
tangent is -J-f, or 21° 10'. Supposing the muzzle of the piece were 
4 ft. above the level, calculating by the Russian formula hereafter given, 
the angle would be 21° 26'. On the 5th August, 1824, a year after 
the completion of the wall, eight 68-pr. carronades, in battery 500 yds. 
from the crest of the counterguard, three 8-inch and three 10-inch 
howitzers at a distance of 400 yds.—in all fourteen pieces—fired 
100 rounds each in about six hours, the howitzers firing live shells filled 
with powder and the carronades solid shot. The 8-inch and 10-inch 
* See “ Aide-Memoire to the Military Sciences,” article Fortification, Permanent. Appendix 
A, p. 62. 
