THE EXHIBITION OP 1S62. 
163 
termed the Minie rifle, Captain Minin, of the French army, 
havings thoug’h he was not the inventor, first brought it very 
prominently forward. Captain Norton was, we believe, the 
real inventor of the expanding bullet. 
Considering the Armstrong and Whitworth rifles as the 
most elaborate English types of the two systems of rifling, we 
will, as far as possible, describe them. In Plate VII. will be 
seen a drawing of the Armstrong gun, of the shell, and the two 
fuzes, and drawings of the ordinary and flat-headed Whitworth 
shot. The process of manufacture of the Armstrong gun is 
so very complicated that it would be impossible without numer- 
ous plates to give a description of any value. Suffice it to say, 
that the gnus are made of wrought-iron bars, coiled and then 
welded together in lengths of about two or three feet. These 
tubes are then welded together and formed into a long barrel. 
This constitutes a core, which is strengthened at the breech, 
where the action of the powder is the greatest, by similarly 
mate cylinders or tubes of wrought iron, which being con- 
structed of such a size that they are too small when cold, are 
put on when expanded by heating. When these cool and con- 
tract, they afford the necessary initial tension. The breech is 
forged solid, and welded on. The gun is loaded at the breech 
through the powerful hollow screw, which is shown in the 
plate. The charge having been inserted, the vent-piece is 
dropped into the slot behind it, and tightened up by means 
of the sorew through which the charge was inserted. The 
vent-piece has a disc of copper on its face, which, by this 
operation, enters the bore, and by its expansion at the time of 
explosion prevents any escape of gas. Through the vent in it, 
the gun is fired. The number of grooves varies in different 
calibres ; in some of the larger ones there being as many as 
forty. These grooves are very shallow, with one side (the one 
on which the shot bears while coming out) rectangular, and the 
other rounded off. The rapidity of twist or pitch of rifling 
varies from one turn in thirty to one turn in thirty-eight 
diameters. The bore of the gun, up to a sufficient distance in 
front of the vent-piece, is smooth and enlarged to form a 
chamber, into which the shot and charge is pushed by hand. 
The following description was given by Sir W. Armstrong, 
of the projectile — the shell, — in a paper printed by the Institution 
of Civil Engineers ; and with some further description is ex- 
tracted from Major Owen and Captain Dames's lectures : — 
The projectile consists of a very thin cast-iron shell, the interior of which 
is composed of forty-two segment-shaped pieces of cast-iron, built up in 
layers around a cylindrical cavity in the centre, which contains the bursting 
charge and the concussion arrangement. The exterior of the shell is thinly 
