THE liOYAL AKTILLEiiY INSTITUTION. 
387 
It is as follows :— 
Suppose a shot, moving* along the bore of the gun, is compelled to 
rotate as shown by the arrow by the bearings at the points A, B, and 
C 3 then, by virtue of its inertia, it will assume a position where the 
rotation is least, and this can only be in the centre of the bore; for it 
will be observed that if it goes to one side—the bottom, for instance— 
it can only do so by taking more rotation, pivoting round the point A. 
Rather than do this, it will centre itself in the bore of the gun. 
Captain Scott, R.N., claims this as an advantage, with his system of 
rifling, which consists of long iron ribs on the shot, giving a sufficient 
amount of bearing surface to prevent any wear of the ribs, which would 
of course interfere with the perfect action of this principle. 
The Woolwich system is well known, and practically consists in 
giving rotation by a single row of soft studs all round the projectile, 
so as to allow of an increasing twist being given to the grooves of the 
gun, and thus reduce the maximum strain caused in giving rotation, 
both on the studs and gun. The small amount of windage given 
between the shot and the bore, is considered sufficient to give accurate 
centring. The windage over the studs, also, is less than over the body 
of the projectile; so that the soft metal studs receive any side blow 
which may be given to the bore of the gun, and thus diminish any 
knocking action that may exist. 
These are all the systems which have been tried in this country 
which have given results entitling them to be considered applicable 
to heavy guns ; but two others may be mentioned, which have been 
adopted or tried by foreign Governments, and which are worthy of 
consideration. 
The Austrian Government tried a very long B.L. gun, which fired 
lead-coated projectiles, but which differed from the Armstrong, not 
only in the breech-loading action, but also in the grooving of the gun. 
The number of grooves was reduced to one-half, and the grooves were 
made very wide, while the lands were very narrow; so that, practically, 
the lands cut readily into the lead coating, and thus diminished the 
