re
the ponderous mass is freed from its casing of masonry, and brought out
at last to open day. It is then thoroughly examined with a view to the
discovery of any latent flaw or imperfection, and, if found complete in
every part, is conveyed away to be the subject of a long series of
finishing operations in another place,--operations many and complicated,
but all essential to enable it finally to fulfill its functions.

These cylinders though very massive and ponderous are not the heaviest
castings made. They are much exceeded in weight by what is called a bed
plate, which is an enormous frame of iron cast in one mass, or else in
two or three separate masses and then strongly bolted together, to form
a foundation on which the engine is to rest in the hold of the ship. The
bed plate can not be seen in the view of the engine room already given,
as it lies below the floor, being underneath all the machinery. A bed
plate weighs sometimes thirty-five tons--which is the weight of about
five hundred men. Such a mass as this has to be transported on ways,
like those used in the launching of a ship. It is drawn along upon these
ways by blocks and pullies, and when brought alongside the ship is
hoisted on board by means of an enormous derrick, and let down slowly to
the bottom of the hold--the place where it is finally to repose, unless
perchance it should at last be liberated by some disaster, from this
dungeon, and sent to seek its ultimate destination in the bottom of the
sea.

The engraving below represents the forges, where all those parts of the
machinery are formed and fitted which consist of wrought iron. The room
in which these forges are situated is called the smith's shop, in the
plan. In the back-ground, a little to the right, is one of the trip
hammers, in the act of striking. The trip-hammer is a massive hammer
carried by machinery. The machinery which drives it may at any time be
thrown in or out of gear, so that the blows of the hammer are always
under the control of the workman. The iron bar to be forged is far too
heavy to be held by hand. It is accordingly supported as seen in the
engraving, by a crane; and only guided to its place upon the anvil by
the workmen who have hold of it. The chain to which this bar is
suspended comes down from a little truck which rests upon the top of the
crane, and which may be made to traverse to and fro, thus carrying
whatever is suspended from it further outward, or drawing it