taken with the left eye.]

A second theory, often broached, in order to account for the
divergence of the charge, is that the barrel which is not being fired,
by its _vis inertia_ in some way causes the shot to diverge. In order
to test this, Mr. Phillips took a single rifle and secured it near the
muzzle to a heavy block of metal, when the accuracy of the shooting
was in no way impaired.

So far the experiments were of a negative character, and the next step
was made with a view to discover the actual cause of the divergence
referred to. A single barrel was now taken, to which a template was
fitted, in order to record its exact length. The barrel was then
subjected to a heavy internal hydrostatic pressure. Under this
treatment it expanded circumferentially and at the same time was
reduced in length. This, it was considered, gave a clew to the
solution of the problem. A pair of barrels was now taken and a
template fitted accurately to the side of the right-hand one. As the
template fitted the barrel when the latter was not subject to internal
pressure, upon such pressure being applied any alterations that might
ensue in the length or contour of the barrel could be duly noted. The
right-hand barrel was then subjected to internal hydrostatic pressure.
The result is shown in an exaggerated form in Fig. 2. It will be seen
that both barrels are bent into an arched form. This would be caused
by the barrel under pressure becoming extended circumferentially, and
thereby reduced in length, because the metal that is required to
supply the increased circumference is taken to some extent from the
length, although the substance of metal in the walls of the barrel by
its expansion contributes also to the increased diameter. A simple
illustration of this effect is supplied by subjecting an India-rubber