After the boring of the barrel, it is placed in a lathe, and the outside turned down to the proper size.  The piece is 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 diagonal line drawn across a pane of glass in a window.  The workman then placed the barrel of the musket upon a rest in such a position that the reflected line in the mirror could be again reflected, through the bore of the barrel, to his eye,—­the inner surface of the barrel being in a brilliantly polished condition from the boring.  When the barrel is placed at the proper angle, which practice