54 
MINUTES OF PROCEEDINGS OF 
mines in order to throw down the revetted counterscarp. Should 
this give us then a formation such as is shown in Fig. 3, the altered 
profiles will admit of the advantageous employment of curved breaching 
and demolition fire from greater distances. This is to be preferred to 
direct breaching, because we can better secure ourselves against the 
splinters which fly back, - * and against the musketry fire of the de¬ 
fenders ; and, generally, the establishment of direct batteries on the 
crowning of the covered way is attended with great sacrifices. 
Fig. 3. 
Direct breaching fire from the crowning of the covered way is, more¬ 
over, impracticable when, owing to the narrowness of the ditches and 
the masonry counterscarp, the escarp cannot be taken deep enough. 
4. Choice of the Point of Impact in Curved Breaching Fire. 
From the experience gained at Julich the method usually pursued 
in the case of direct breaching fire from smooth-bore guns—which 
consists in cutting out a portion of the masonry by means of a hori¬ 
zontal cannelure and of a vertical one at each of its ends—has been 
judged as advantageous for curved breaching fire also. 
The height at which the horizontal cannelure should be placed, and 
which—as in the case of direct breaching fire—depends on the profile 
of the rampart to be breached, was taken, in the case of ordinary shells 
and very strong profiles difficult to breach, at one-third the height of 
the scarp. According to later experience, with 15 c.m. shells 2\ calibres 
in length it may be placed at half that height ; because, owing to the 
greater bursting effect of these projectiles, the scarp gets shattered to a 
much greater depth below the cut. 
It is evident that if we base the calculation of the angle of descent, 
and consequently the determination of the charge and elevation, on a 
given point of impact at a fixed height, and make use of this charge 
and elevation, at least half the shots will be thrown away, because the 
lower half of the set or sheaf of trajectories ( Flugbahngarbe ) will be inter¬ 
cepted by the covering mass, and consequently no shot can strike below 
this point . But if, however, we wish to group as many shots as possible 
* Shell splinters and stones are generally thrown back as far as 150 metres ; a few larger stones 
—some kilogrammes in weight—flyback more than 200 metres; and the bottoms of the shells 
as far as 450 metres, (Prussian experiments with the short 15 c.m.) 
