EFFECT OF SHELL OH MUD WALLS. 
627 
Wall of clay, of very adhesive nature. 20 ft. high in rear or interior 
of the work; the front varying in height up to 30 ft., owing to the 
irregular nature of the ground, which apparently had not been levelled 
at any tiipe, with a thickness at base of 24 ft., varying up to 10ft. 
thick at top of wall. 
The whole of the shell filled with sand broke up, and so did the 
plugged shell filled with powder, as far as could be ascertained; in 
some of the latter, however, the bursting charge did not ignite, and 
.on examining them it was found that the bursting charge had caked 
1 nto a hard mass, although it was in perfectly good order before firing. 
I tried both percussion fuzes with the safety-pin withdrawn and with 
the safety-pin left in, and for breaching purposes in mud walls I prefer 
the latter, as the fuze appeared to me to be too sensitive in the former 
case. Not a single shell with the safety-pin left in failed to burst, and 
the effect of salvos with these shell was very great, I am of opinion 
that the wall should be first prepared by firing single shells, fuzed 
either with percussion fuze with safety-pin left in, or time fuzes bored 
long, until it has been well undermined, and after that the effect of 
salvos in bringing down large masses will probably be very great. 
In these operations no fuzed shell failed to burst; one shell, time- 
fuzed, burst at the muzzle. I consider that of the shell fuzed with 
time fuze those bored 3/10 produced the best effect, those bored at 2/10 
seemed to burst on impact, whilst those bored 4/10 had the action 
delayed, but did not bring down so much debris as the others. 
C. CROSTHWAITE, 
Major E.A., 
Comdg. “H” 1st Bde. R.A. 
T). 
Report on Experimental Practice carried on at the Walls of Old Kandahar, by 
F\2 R.A., on the 6th April , 1881, under orders of Brig.-General De-Vitre, 
R.H.A., Comdg. R.A., S. Afghanistan. 
The wall was built of sun-dried bricks and clay; its height was about 
18 ft. It was 24 ft. thick at the bottom, diminishing to 15 ft. about 
5 ft. up, and tapering to lift, at the top. Kange 395yds. Eleva¬ 
tion 26'. 
