GOLD MEDAL PRIZE ESSAY, 1879 . 
515 
Velocity. 
1600 f.s. 
1500 f.s. 
1400 f.s. 
1300 f.s. 
16-pr. range 
yds. 
166 
yds. 
345 
yds. 
528 
yds. 
731 
24 „ /, 
'264 
541 
833 
1151 
Calibre, 3‘6ins. Both shells fired with same M.V. (1700 f.s.) 
(4) In order to obtain this high velocity, so essential to our purpose, 
without straining too highly the gun, and, what is almost of more 
importance, the shell, we must employ chambered guns and air-spaced 
cartridges; the latter to allow us to generate a large volume of gas 
at low tension, and the former to allow of the cartridges, when so air- 
spaced, being of moderate length. If air-spaced cartridges are used in 
guns having no enlarged chambers, their length has to be increased to 
an inordinate degree. Wave pressures are apt to result, even if the 
charge be ignited through a forward vent; moreover, the undue 
elongation of the powder-chamber is so much useful length cut off the 
gun. The results hitherto attained in this manner ( i.e ., chambering 
and air-spacing) are highly satisfactory ; but we are undoubtedly only 
on the verge of an enormous field of enquiry, the thorough exploration 
of which must be the work of future experiment. The knowledge of 
the laws of the combustion of gunpowder is being unfolded to us slowly, 
but we have the consolation of knowing that more has been done in 
this direction in the last five years than in the preceding five centuries. 
(5) Finally, the question of rotation must be satisfactorily worked 
out. The best method appears to be that adopted in some countries of 
copper rings with a B.L. gun. This system gives excellent results for 
accuracy of practice, and supports the walls of the shell. 
[Since the above was written, the 6-in. B.L. Armstrong gun has Possible 
appeared, firing a 70-lb. shell with 2000 f.s., and having only a low Say beT 
pressure on the powder-chamber. It would be quite possible, we in 
imagine, to make a 12-cwt. gun to throw a 20-lb. shell with that velocity, 
velocity; the calibre being about 3*3 ins. Such a gun would indeed 
realise our hopes. The question would be, how to get a carriage to 
stand the recoil. For the production of such a weapon and carriage we 
must live in hope.] 
21. We now come to the most difficult part of the whole question. The car. 
As we said above, improvements have taken place so quickly in gun nage - 
manufacture, powder and the way of burning it, rifling, &c., that the 
gun manufacturer can no doubt make the guns we want, even with 
less weight than above allowed—viz., 12 cwt. The question arises, Can 
a carriage be made ? A gun very light compared with the weight and 
velocity of its projectile must cause a very great strain to the carriage ‘ 
but there appears to be no doubt that a slow-burning powder, although 
it does not lessen the total amount of work done, provided the muzzle 
velocity be the same, greatly lessens the maximum pressure on the car- 
