supported in the lathe by
means of mandrels inserted into the two ends, and there it slowly
revolves, bringing all parts of its surface successively under the
action of a tool fixed firmly in the right position for cutting the work
to its proper form. The barrel has a slow progressive as well as rotary
motion during this process, and the tool advances or recedes very
regularly and gradually, forming the proper taper from the breech to the
muzzle, but the main work is performed by the rotation of the barrel. In
the boring, it is the tool which revolves, the piece remaining at rest;
but in the turning, the barrel must take its part in action, being
required to revolve against the tool, while the tool itself remains
fixed in its position in the rest.

A curious and interesting part of the operation of manufacturing muskets
is the straightening of the barrel. This straightening takes place
continually in every stage of the work, from the time the barrel first
emerges from the chaotic mass produced by heating the scalp, until it
reaches the assembling-room, where the various parts of the musket are
put together. As you enter the boring and turning rooms, you are struck
with surprise at observing hundreds of workmen standing with
musket-barrels in their hands, one end held up to their eyes, and the
other pointing to some one of the innumerable windows of the apartment.
Watching them a few moments, however, you will observe, that, after
looking through the barrel for half a minute, and turning it around in
their fingers, they lay it down upon a small anvil standing at their
side, and strike upon it a gentle blow with a hammer, and then raise it
again to the eye. This is the process of straightening.

In former times, a very slender line, a hair or some similar substance,
was passed through the barrel. This line was then drawn tight, and the
workman, looking through, turned the barrel round so as to bring the
line into coincidence successively with every portion of the inner
surface. If there existed any concavity in any part of this surface, the
line would show it by the distance which would there appear between the
line itself and its reflection in the metal. This method has not,
however, been in use for over thirty years. It gave place to a system
which, with slight modification, is still in practice. This method
consisted in placing a small mirror upon the floor near the anvil of the
straightener, which reflected a diagona