74- 
minutes OF PEOCEEDINGS OF 
After 484 shots, of which 336 struck the scarp, its upper half 
was in ruins, and a breach 6’5 metres wide was formed, and was con¬ 
sidered as practicable. In this instance the peculiar strength of the 
scarp must be taken into consideration. It was 5 metres thick at the 
b^se and 3 at the cordon, and strengthened by counter-forts 4 metres 
thick and 4*5 metres apart. It carried an earthen parapet 5’6 metres 
high, which at 1 metre ; s height above the base had a berm 1 metre 
wide. The revetment was built of brick, and had behind it a lining 
wall of very hard blocks of primitive rock. 
A breaching experiment carried on at Gfraudenz under almost exactly 
similar circumstances, with 21 c.m. B.L. guns, gave also very satisfactory 
results, in that 190 shots sufficed to produce as practicable a breach as 
that effected by the 15 c.m. gun. We are therefore justified in the 
opinion that the method of demolishing the upper half of the scarp by 
means of curved fire will, in future, supersede the old plan of cannelure 
cutting. And although, in demolition fire, a greater expenditure of 
ammunition is necessary to bring down a particular portion of the 
scarp, this is compensated for afterwards; because a breach produced 
by horizontal and vertical cuts has still to undergo a further tolerably 
long bombardment before it is practicable. 
In demolition fire the conditions are essentially favourable. The 
masses of masonry first shot down form a mound of rubbish which lies 
at a natural slope at the foot of the scarp, and which in no way inter¬ 
feres with the penetration or the bursting effect of the shells which 
strike the upper half of the scarp. On the contrary, this kind of 
breaching possesses the advantage that the mound gets more and 
more augmented and covered with earth at each shot. Moreover, the 
method of proceeding to be observed during the bombardment is con¬ 
siderably simplified, and it is sufficient to fix the lowest point of impact 
(when deciding on the angle of descent and the charge) at half the 
height of the scarp, and the mean point of impact (when deciding on 
the elevation) at one-fourth its height from the top. All the com¬ 
plications which are entailed by the formation of the horizontal, to say 
nothing of the vertical, cuts are avoided, and it is only necessary to 
shift the mean point of impact laterally from time to time to effect the 
demolition of the _scarp to the-desired extent. 
10. Calibre, Distance, and Charge. 
The short 15 c.m. B.L. gun is the most important and efficacious 
piece. Except in the case where it is necessary for the projectiles to 
possess considerable range and striking power, or where light ordnance 
only can be employed in the armament, this gun is universally ap¬ 
plicable in every kind of curved fire. 
Owing to their greater bursting effect, the shells 2\ calibres in length 
are far superior to the ordinary ones, not only for curved breaching 
and demolition fire, but also for enfilading. 
In enfilading entire fronts at a distance of 1500 to 3000 metres both 
the long 15 c.m. and the short 15 c.m. guns may be employed, and as 
a rule with heavier charges. 
