in, as may
be required. All the cranes, both in the smith's shop and in the
foundry, are fitted with the same contrivance. These trucks are moved by
means of a wheel at the foot of the crane.

[Illustration: THE FORGES.]

On the extreme right of the picture, and somewhat in the distance, may
be seen another trip-hammer with a bar upon the anvil beneath it, this
bar being suspended likewise from a crane. When the iron becomes too
cold to yield any longer to the percussion, the hammer is stopped, the
crane is swung round, and the iron is replaced in the forge to be heated
anew; and at length, when heated, it is brought back again under the
hammer as before.

The forging of shafts requires heavier machinery even than this. The
enormous mass of iron that is in this case to be forged, is bricked up
in a furnace to be heated, and remains there many hours. The masonry is
then broken away and the red hot beam is swung round under the hammer,
as seen below. It is suspended from the crane by heavy chains, and is
guided by the workmen by means of iron handles clamped to it at a
distance from the heated part, as seen in the engraving in the adjoining
column. The hammer is lifted by means of the cam below it, as seen in
the engraving below. This cam is a projection from an axis revolving
beneath the floor, and which, as it revolves, carries the cams
successively against a projection upon the under side of the hammer,
which is partly concealed in the engraving by the figure of the man.
When the point of the cam has passed beyond the projection it allows the
hammer to fall.

[Illustration: HEATING A SHAFT.]

[Illustration: FORGING A SHAFT.]

While the process of forging such a shaft is going on, one man throws
water upon the work, to effect some purpose connected with the scaling
of the iron, while another, with an instrument called the callipers,
measures the diameter of the shaft, to regulate the size, as the forging
proceeds.

[Illustration: THE LATHES.]

The shafts, when forged, are to be turned in a lathe, and the engine
used for this purpose is represented on the left in the engraving below.
The shaft itself is seen in the lathe, while the tool which cuts it as
it revolves, is fixed firmly in the "rest," which slides along the side.
The point of the tool is seen in the engraving, with the spiral shaving
which it cuts falling down from it. The shaft is made to revolve by the
band seen coming down obliquely from above,