188 
BURSTING OP HEAVY GUNS. 
exception of the inner coiled tube. It weighs 95 cwt. Sir W. Palliser 
proposed to fire five rounds in succession from it, unless tlie gun gave 
way during the trial; pebble powder to be used throughout. He 
fixed the weights of powder and shot of the first round on a principle 
of proportion to the 38-ton gun ammunition—that is, 95 cwt. being 
one-eighth of 38 tons, he considered that ammunition weighing 
one-eighth the amount of that fired in the latter gun would throw a 
similar strain on the former. It will be seen that 110 lbs. and 85 lbs. 
are eight times 13 lbs. 12 ozs. and 10 lbs. 10 ozs. respectively, while 
688 lbs. and 575 lbs. are not so much as eight times as great as 88 lbs. 
and 77 lbs.; consequently, if Sir W. PallisePs theory is correct, he 
would not be doing his own gun full justice. Probably artillerists 
generally would not be prepared to admit his theory, however, for a 
moment. It seems ungracious to cavil at the conditions of so really 
audacious an experiment. There can be no question that the pro¬ 
gramme was very severe, and that Sir W. Palliser showed great 
confidence in his gun to undertake it; but to benefit by it, it is 
necessary to analyse carefully, and I must begin by pointing out that 
there is considerable difficulty in ascertaining the strain really incurred 
by the gun. Pebble powder gives a much less strain on a small gun 
than a larger. To carry proportions out fully, the grains should have 
been much smaller, though I am not prepared to say that one-eighth 
the size would have been the proper dimension. I have before 
observed that I do not think it fair to expect Sir W. Palliser to use 
R.L.Gr. powder—as has been suggested—merely because it would be 
more severe, or because it was at one time the service powder for guns 
of this size. I believe, however, that it was very desirable to use 
pressure gauges in the gun, in order to get the full benefit of the 
experiment and satisfy objections. That objections to making a 
comparison between powder results irrespective of size of grain are 
not frivolous, may be seen from the fact that nearly equal charges of 
pebble and R.L.Gr. powder in a 64-pr. gun have given about 5 tons and 
25 tons pressure respectively. On Sir W. Palliser*s side it may be 
mentioned that the service battering charge for the Woolwich 7-in. 
gun now consists of “ 30 lbs. of pebble powder, or 22 lbs. of R.L.Gr. 
powder,” which furnishes an orthodox scale of comparison between 
the effect of these two classes of powder in a 7-in. bore [vide the 
Official Laboratory Treatise on Ammunition); so that it may be urged 
that pebble powder is a recognised class of powder for a 7-in. gun, 
and that the pressure may be probably well known and registered in 
the Royal Arsenal. 
Sir W. Palliser contemplated the use of pressure gauges, and bor¬ 
rowed some from the Arsenal with a view to supplying suitable gauges 
for the case before us, but concluded that to enter them in the breech 
would weaken it, and a gauge there, or in rear of the rear projectile, 
would not give the pressure at the most important place, while a 
gauge in the base of the front projectile would, he considered, be 
destroyed by impact of the point of the rear projectile. I regret this 
decision, because I believe that the point of the rear projectile 
would not strike the base of the front one, at all events when the 
