tube to internal pressure. Supposing the material to be sufficiently
elastic and the pressure strong enough, the tube would ultimately
assume a spherical form. It is a well known fact that heavy barrels
with light charges give less divergence than light barrels with heavy
charges.

After the above experiments it was hoped that, if a pair of barrels
were put together parallel and soldered only for a space of 3 in. at
the breech end, and were then coupled by two encircling rings joined
together as in Fig. 4, the left-hand ring only being soldered to the
barrel, very accurate shooting would be obtained. For, it was argued,
that by these means the barrel under fire would be able to contract
without affecting or being affected by the other barrel; that on the
right-hand, it will be seen by the illustration, was the one to slide
in its ring.

A pair of able 0.500 bore express rifle barrels were accordingly
fitted in this way. Fig. 3 shows the arrangement with the rings in
position. Upon firing these barrels with ordinary express charges it
was found that the lines of fire from each barrel respectively crossed
each other, the bullet from the right-hand barrel striking the target
10 in. to the left of the bull's eye, while the left barrel placed its
projectile a similar distance in the opposite direction; or, as would
be technically said, the barrels crossed 20 in. at 100 yards, the
latter distance being the range at which the experiment was made.
These last results have been accounted for in the following manner:
The two barrels were rigidly joined for a space of 3 in., and for that
distance they would behave in a manner similar to that illustrated in
Fig. 2, and were they not coupled at the muzzles by the connecting
rings they would shoot very wide, the charges taking diverging