144 
MINUTES OF PROCEEDINGS OF 
determine the hits precisely. Prom a great number of shots the “ point 
of mean impact” was determined, and the line of fire so obtained was 
transferred to the middle of the exposed face of the sluice in an analogous 
manner to that described in the case of the other sluice. The visible point 
from which the line of fire was transferred sideways was the salient angle of 
the lunette, which was shown on the plans of the fortress. As a check, and 
in order to apply the correction due to the weather or other influences, the 
shooting was resumed against the face of the lunette from time to time. 
The angle of the descent of the shot was about 7°; the line of fire formed 
with the face of the sluice in front of the curtain 15-16 an angle of about 
63°, and with the sluice in front of lunette 63 an angle of 44°. The final 
velocity was about 918 f.s., which was sufficient to obtain deep penetration. 
In order to prevent any repairs being carried out by the Prench, the 
besiegers fired shrapnel from time to time, especially by night. 
In the manner thus described, the bombardment was maintained with 
two guns against the sluice in front of the curtain 15-16, and with one gun 
against the sluice in front of lunette 63. The effect of this fire might be 
inferred from the conduct of the besieged, who concentrated a heavy fire 
from their batteries on these guns. 
After the fall of Strasburg, it was seen that these sluices were very 
strongly built. The stone-work was composed of huge cut stones, and about 
6 ft. thick, and the wooden sluice-gates were of the smallest possible 
dimensions. The bombardment had nearly destroyed the wooden sluice¬ 
gates, and had displaced or destroyed the stone-work. In order to repair 
these damages, the Prench had used heavy timbers and some 50,000 sand 
bags and corn sacks filled with earth, stones, &c. 
The water in the ditches had been visibly lowered, but the early surrender 
of the fortress relieved the besiegers of any further care in this respect. 
June, 1872. 
