ORGANISATION AND EMPLOYMENT OP SIEGE ARTILLERY. 
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wall away down to the depth necessary. In this case, the projectile 
falling from a height, cuts downwards as well as into the masonry, and 
if the action of the fuzes be restrained till the shell has penetrated its 
full distance, the effect of large bursting charges is very marked. 
In 1873, the Prussians experimented at Graudenz with 12, 15, and 
21 c.m. guns, to compare the methods of breaching, by cutting cannelures 
and by simple demolition of the upper half of the wall, slow percussion 
fuzes—exploding one second after striking—being used. 
Results are stated thus (having regard to the 15 c.m. gun) : “The Erpeti- 
circumstances were more favourable for f cutting 3 than for f demolition/ Sraudenz 
whilst in the former case the angle of impact was 75°, and the striking 
velocity 770 f.s., in the latter they were 57°, and 669 f.s., respectively. 
Notwithstanding this, it would have required, in the first instance, cutting* by 
63 hits per metre of the width to make a practical breach ; in the cannelures - 
second instance, only 52 hits per metre would have been necessary.” 
This result confirms French experiments, that “by simple demolition 
instead of cutting, a practicable breach can be made with a less expen¬ 
diture of ammunition, and that a practicable breach can be made by 
demolition, where the lowest point of striking is half way down the 
wall, whilst an immediate observation of the breach is not at all 
requisite.” 
The result of these trials was indeed so favourable, as to justify the Conclusion 
opinion that “ circumstances, favourable to cutting, will rarely occur in Ge™an by 
war, so that this mode of firing will be the exception.” Whilst ^ a c ®J s e ^ 
. Count Bylandt Rheidt, of the Austrian service, says “ the mode of 
demolishing the upper half of escarps by means of curved fire will in 
future supersede the old plan of cannelure cutting.” 
Particular local circumstances must be the guide in each case, as to Considera- 
which method of breaching is likely to prove the more advantageous, whicifme- 
It should be borne in mind that when the masonry is weak, the cutting {JefchLg 
system would require to destroy less of it ; and that if direct fire can to employ, 
be used, and an immediate observation of the striking of the shots be 
obtained, this system is likely to be the quicker; but the execution of 
horizontal and vertical cuts becomes considerably more difficult with an 
increase of thickness of wall, whilst this difficulty is added to as the 
angle of descent becomes greater. Breaching by demolition appears 
advantageous as destroying counter-arches more effectually, so that 
these fall with the masonry instead of remaining standing as was often 
the case when cannelure cutting was employed, their after destruction 
was always difficult; further, less accuracy is necessary (an important 
point in the case of curved fire), the masonry falls in smaller blocks, 
thereby forming a more accessible breach, and the wall is attacked 
at its weakest part. 
Further conclusions, derived from the Graudenz experiments, state Comparison 
“ the practicability of demolition at angles of descent, to 15° may be different 01 
accepted; and, in regard to the relative breaching powers of guns of breacHn^ 
different calibres, a comparison of the 15 c.m. and 21 c.m. guns, at all 
stages of the experiments, gave proportional results—that is to say, 
with the same striking velocities an equal weight of projectiles was 
required to produce equal results. The advantage of the heavy calibre 
