56 
MINUTES OF PROCEEDINGS OF 
pensable; and therefore, as a rule, heavy charges combined with short 
ranges are the most useful. Should it not be possible to combine both, 
then a greater initial velocity, and consequently a greater distance, is 
to be preferred, even though the probability of hitting may not be all 
that could be desired. This is, however, only possible when we are 
not tied down to any particular spot in selecting the position of 
the gun. 
Lastly, in choosing the lowest point of impact, it has further to be 
taken into consideration that with large angles of descent it maybe fixed 
somewhat higher; because, according to all experience, the horizontal 
cut always gets widened downwards in proportion to the depth the pro¬ 
jectiles penetrate the scarp, especially when breaching with 15 c.m. 
shells 2\ calibres long—these shells having almost twice as great a 
bursting effect as the ordinary ones. At an experiment at Silberberg 
with the short 15 c.m. gun (angle of descent 6°, final velocity 175 metres), 
the mean point of impact got lowered by 0*4 metre by the time the scarp 
had been quite broken through. It may be taken for granted that, 
cceteris paribus , this would have been the case in a greater degree with 
a higher angle of descent. 
5. Choice of the Point oe Impact in Curved Demolition Eire. 
Curved demolition fire is employed against raised buildings, capon- 
nieres, reduits , and detached walls of every kind. 
The method of proceeding, when a certain line of embrasures has to 
be struck, is the same as in producing a horizontal cut. The intended 
point of impact lies, in this case, in the line of embrasure roofs. The 
proper weight of the charge will be calculated from the angle of descent 
for this line and from the range. In the practice tables are to be 
found the 50 per cent, vertical spread for this charge and for the given 
distance. The lowest point will be taken at half this vertical spread 
below the line of embrasure roofs, and the angle of descent for it 
calculated exactly. 
Very frequently the profile conditions will be so unfavourable that 
only small charges and high angles of descent can be employed, and 
the probability of hitting will consequently be slight. In the case, 
however, of small reduits with but little strength of scarp, which a little 
battering would render untenable, a systematic destruction of the rows 
of embrasures may be dispensed with. 
To produce a breach in a detached wall, or to bring it down, 
comparatively few blows, distributed over the face that has to be 
battered, are sufficient. The greatest probability of hitting would be 
obtained if the lowest point of impact were taken at the foot of 
the wall, and the point aimed at at half its height. In the case, 
however, of fortifications planned with tolerable judgment, walls of 
this nature are protected within a certain angle of descent. It has 
therefore to be ascertained how low down the lowest point of impact 
can be taken, and the mean point of impact then placed at the centre 
of the strikeable surface. If the lowest point of impact be too high 
