muzzle--that is, at eight times the length of the cartridge from the
breech--the pressure will be but one ninth of that originally set up.
Remember, this is on the supposition that the powder has been entirely
converted into gas before the shot begins to move.

Now, suppose the powder to be of a slow-burning kind, and assume that
only one-third of it has been converted into gas before the shot starts,
then the remaining two-thirds will be giving off additional gas as the
shot travels through the bore. Instead, therefore, of the pressure
falling rapidly, as the shot approaches the muzzle, the increasing
quantity of gas tends to make up for the increasing space holding it.
You will at once perceive that the slower the combustion of the powder
the less difference there will be in the pressure exerted by the gas at
the breech and at the muzzle, and the greater will be the advantage,
in point of velocity, of lengthening the bore, and so keeping the shot
under the influence of the pressure. Hence, all recent improvement has
tended toward larger charges of slower burning powder, and increased
length of bore. And it is evident that the longer the bore of the gun,
the greater is the convenience of putting the charge in behind, instead
of having to ram it home from the front. I may here remark, that the
increased length of gun necessary to produce the best effect is causing
even those who have possessed breech-loaders for many years to rearm,
just as completely as we are now beginning to do. All the old short
breech loading guns are becoming obsolete. Another great advantage of
breech-loading is the facility afforded for enlarging the powder chamber
of the gun, so that a comparatively short, thick cartridge may be I
employed, without any definite restriction due to the size of the bore.

There is yet one more point in which breech-loading has recently been
found, in the Royal Gun Factory, to possess a great advantage over