• THE ROYAL ARTILLERY INSTITUTION. 
481 
in tlie matter. They have been frightened by a bugbear. They held 
that bronze was too soft to stand the wear of rifled projectiles,, and that 
if the metal of the studs were softer than that of the gun—perhaps the 
only condition upon which the guns could stand the wear—the studs 
would be knocked to pieces in travelling. 
3. The French, at the outset of their experiments, got deplorable 
results from their bronze muzzle-loading guns. As the shell lay at the 
lower surface of the bottom of the bore, the cast-iron was in contact 
with the gun-metal; the stud was used merely to compel the shell to 
follow the twist of the groove, and not to protect the bronze of the bore 
from the cast-iron. What was the consequence ? The windage or 
space between shell and gun being at the upper surface of the shell, 
on the explosion of the charge, the upper edge of the base of the shell 
struck the top of the bore, while the shoulder of the shell was hammered 
down on to the lower surface. This sectional diagram will perhaps 
illustrate the effect. You see that the shell did its best to revolve 
round its shortest axis, and you may imagine how a shell thus started 
behaved itself as it passed 'along the bore. It was about on a par with 
the old round shot, and some fifty rounds rendered the gun unserviceable. 
Enlightened by this misconduct, they made the studs project farther 
beyond the surface of the shell, so that when it lay as before, at the 
lower surface of the bottom of the bore, there was a clearance between 
cast-iron and bronze.* The gun was thus subject to the friction 
between the zinc of the stud and the bronze of the driving sides of the 
grooves. Under these conditions the guns shot well and endured long. 
The Austrians having suffered under these guns in 1859 in Italy, 
studied the matter, and in 1863 introduced a centering system applied 
to muzzle-loading guns. The diagramf will give you an idea of that 
system. The projectiles are formed of a similar figure to, but of a 
slightly smaller diameter than the bore of the gun, and are covered 
with a coating of an alloy of tin and zinc. This alloy being softer than 
bronze, the friction between the two metals is favourable to the latter 
in point of wear; but owing I suppose to the sharp angles of the 
surface of the alloy, each projectile has to be carried well greased in a 
canvas bag in the ammunition boxes. This appears to me to be the 
defect of the arrangement. 
The French guns fire between two and three thousand rounds with 
satisfactory practice to the last. The Austrian guns fire some 1500 
rounds, after which service they are recast. 
I have thus shown you, I hope, how a projectile composed of the 
hard metal, cast-iron, can by a little artifice be fired from a gun made 
of a comparatively soft metal like bronze. It is, in short, by isolating 
the cast-iron from the bronze. 
* Vide Eig. 1. 
f Vide Eig. 4, representing a vertical cross section through the gun and shell, the latter lying 
at the lower surface of the here. When centred, the windage forms six lozenge-shaped figures 
when seen in section. 
[VOL. VI.] 
63 
