ORGANISATION AND EMPLOYMENT OP SIEGE ARTILLERY. 
437 
and 6 ft. at bottom: 32 rounds per metre were thus required for the 
breach, but it was still in an incomplete state; unfavourable weather, 
and irregularities from want of practice in serving the gnus, materially 
increased the difficulties.* 
For the right face of Bastion 11, with oblique fire 80°, range 875 yds., 
angle of descent 4° 30", 20 rounds per metre formed a breach 96 ft. 
wide; the horizontal cut was clean and regular at J distance from the 
base, and after the vertical cuts were made, the wall was thrown down 
in two large pieces. 
Again, in breaching Bastion 12 by front fire, range 790 yds., angle 
of descent 3° 50', vertical and horizontal cuts were made with great 
exactitude, and after 27 rounds per metre, a nearly practicable breach 
was made, when the place capitulated; circumstances were particularly 
unfavourable in the last case. 
The above shewsfi the advantage derived from the greater accuracy 
and penetration with small angles of descent, as enabling breaches to be 
more quickly executed, and with a less expenditure of ammunition. By 
using indirect fire, breaches may be made at very considerable ranges—■ 
they can, therefore, be formed at an earlier stage of the siege than 
formerly. The fact that a practical breach exists, and storming has 
become possible, will be sure to exert a depressing influence on the 
garrison, whilst the besiegers will become accordingly encouraged. 
General von Decker, in his observations on the use of indirect fire 
at the siege of Strasbourg, alludes to this as follows 
1. The breaching facilitated greater rapidity in the engineer's 
work; and 
2. This premature breaching had considerable influence in causing 
the garrison to decide on capitulating; and “ hence it follows 
that breaches quickly (soon after investment) formed, contri¬ 
bute mainly to the speedy fall of a place.” Had direct fire 
been employed it could not have been commenced for a fort¬ 
night later. 
In the late war the Germans, when breaching unseen walls by 
indirect fire, derived great assistance from experiments carried out in 
1869, and the results of these as afterwards laid down for general use. 
The chief difficulty lies in obtaining the exact charge for the given 
range and angle of descent, others arise from the fact of not seeing the 
shots strike, and the inability of correcting errors in direction or 
elevation. 
The plan which in 1870 shewed itself most successful, was to fire at 
some visible part of the wall, and obtain a point of mean impact close 
to the selected point of aim for the breach. The necessary alterations 
of elevation to hit the escarp at the height proposed for the horizontal 
* “ Prussian Portresses and Siege Artillery,” four parts (from 1870 to 1875). 
f No doubt the great difference in the number of rounds per meire of width needed to breach 
Lunette 53 was partly due to the fire being very oblique as well as indirect. Observations made 
after the fortress fell C£ brought to light that with the combination of charge and angle of descent 
used there, it had been more of a demolition than a cutting.” 
Practical 
directions 
for 
breaching. 
