k done upon them is paid for by the piece. It will
scarcely be expected that I should describe all the processes included
in the four hundred separate operations performed in the manufacture of
the musket, and I shall therefore content myself with alluding to a few
of the most important or curious among them.

The gun-barrel, after it arrives at the works on the hill from the
water-shops, is taken to the old armory buildings to be rifled. For this
purpose it is placed in a horizontal position in an iron frame, and held
there very firmly. The instruments which perform the rifling are short
steel cutters placed within three apertures situated near the end of an
iron tube which is carried through the bore of the barrel by a slow
rotary and progressive motion. The cutters are narrow bars of steel,
having upon one side three diagonal protuberances of about one-sixteenth
of an inch in height and half an inch in width, ground to a very sharp
edge at the top. It is these which produce the rifling. The three
cutters, when inserted within the iron cylinder, form upon their inner
surface a small cavity which decreases towards the top. Into this is
inserted a small iron rod attached to the machine and revolving with it,
but so controlled by a connecting cog-wheel that the rod is pressed at
every revolution a little farther into the cavity between the cutters.
The effect of this operation is to increase the pressure of the cutters
upon the inner surface of the barrel, and thus gradually deepen the
corrugations produced by the rifling. The rods make twelve revolutions
in a minute, and it occupies thirty minutes to rifle a barrel. There are
twenty-seven of these rifling-machines in constant operation day and
night. This process is the last which takes place within the barrel, and
it leaves the bore in a highly polished and brilliant condition.

Among the innumerable machines which arrest the attention of the visitor
by the beauty and grace of their operations is the broaching-machine.
This is designed to cut out and polish the inner surface of the bands
which encompass the barrel and stock. These bands are irregular in
shape, and cannot, therefore, be bored out as the barrel is. When they
emerge from the drop, or swaging-machine, they are somewhat rough both
interiorly and exteriorly, and then undergo a series of operations which
leave them in a highly finished condition. The first of these is called
broaching. A cavity is made under