886 
MINUTES OF PKOOEEDINGrS OF 
form more to the trajectory, but also to the face of the target, which 
generally has a slight inclination backwards. It seems that this action 
of the gas would not be sufficient to upset the stability of the axis ; 
because it is evident to all, from the noise that a rifled shot makes 
on ricocheting, that the stability of the axis is not upset, but only that 
the point is very much deflected, which causes the regular roaring noise 
which is heard, each gyration being distinctly traced by the ear. Now, 
if the severe blow on striking the ground, which causes so great a de¬ 
flection of the point, is not sufficient to upset the stability of the axis, 
it is scarcely probable that the lesser blow of the gas on the base of the 
shot, which produces a much smaller deflection, would be sufficient to 
do so. 
This view is strictly in accordance with the fact that the best remedy 
for want of centring is to be found in a long gun. All our longest 
rifled guns shoot best; and, if what has been stated be correct, it is to 
be expected that they should do so; for the longer the gun, the less 
will be the stress of the gas as the shot leaves the muzzle, and the less 
will be the knocking, if any, against the sides. 
It was found in the Bashforth experiments, that the 9-in. gun gave 
less resistance of the air when fired with 36 lbs. of R.L.G., than with 
43 lbs. This appears to support the idea. Practically, it was found 
that though 43 lbs. gave 40 ft. more velocity than 36 lbs., yet the latter 
charge would have a greater striking effect at 2000 yds. 
Too much attention has hitherto been given to centring in the bore. 
What is wanted is, that the projectile shall be centred as it leaves the 
gun. It may be centred all along the bore, but if it receives a blow 
from the gas as it leaves the gun, all the advantage will be thrown 
away. If, by centring in the bore, any knocking against the sides can 
be mitigated, this will undoubtedly be an advantage. We ought, how¬ 
ever, to take a lesson from the results of experience, and it will 
generally be admitted that to use a long gun is the best method of 
ensuring accurate centring, and consequently accurate shooting. 
A great many methods have been tried, with the view of securing 
accurate centring. The first, and perhaps the best, was Sir William 
Armstrong’s system of lead-coating. The shot was kept jammed in 
the bore through its whole length, and could not possibly wabble about. 
His shunt gun also provided for centring as the shot left the muzzle, 
by shallowing the grooves just before the shot effected its passage out 
of the bore. Sir Joseph Whitworth tries to get centring by making his 
shot as nearly as possible a mechanical fit, with a considerable amount 
of success. It is probable, however, that his taper base has something 
to do with the accuracy of shooting he has attained, for it will allow 
the gas to act more uniformly round the base of the shot as it leaves 
the gun. This taper base, however, involves a semi-flat head, so as 
to avoid too great deflection; but the greater resistance of the air 
which accompanies this is objectionable, and should be avoided if 
possible. 
Another method, which has found many advocates, consists in making 
the shot centre itself. 
