s an example of Portable Steam Engines, of which there are large numbers
in this country of different manufacturers, we give the representation
(fig. 67) of one made by J.C. Hoadley, of Lawrence, Mass.

[Illustration: Fig. 67.]

In these machines, the rules and proportions of the locomotive engine are
adapted to the requirements of stationary power, for all purposes under
forty horse power. The leading ideas are: high velocity, high pressure,
good valve motion, large fire-box, numerous and short flues, and steam
blast. The characteristic features are: great strength of boiler, fully
adequate to bear with safety 200. lbs. pressure per sq. in., great
compactness and simplicity, large and adjustable wearing surfaces, and the
entire absence of all finish, or polish, for mere show.

The cylinder is placed over the centre of the boiler, at the fire-box end,
so that the strain due to the engine is central to the boiler (which serves
as bed plate); the starting valve is under the hand of the engineer when at
the fire door; and both ends of the crank shaft are available for driving
pulleys.

For the sake of compactness, the cylinders are set low, by means of a
depression in the boiler between the stands of the crank shaft, to admit of
the play of the crank and connecting rod. All the parts are attached to the
boiler, which is made of sufficient strength to bear all extra strain due
to the working of the engine.

They have feed water heater, force pumps, Jackson's governor and valve,
belt for governor, belt pulley, turned on the face, steam gauge;
everything, in short, necessary to the convenient working of a steam
engine. All engines are fired up and tried before they leave the shop, and
they are warranted tight, safe, and complete.

A strong and convenient running gear, so arranged as to be easily attached
and detached at pleasure, is furnished, if desired; forming, when separate,
a useful wagon.

[Illustration: Fig. 68.]

Fig. 68 is a compact vertical engine, as built by R. Hoe & Co., of this
city. It is intended to drive printing presses, but is adapted to any kind
of work, and is especially suited to such places as require economy of
space. Although the value of expansion has been called in question by some
of the engineers of the United States Navy, and under an appropriation from
Congress is now to be made the subject of experiment; yet, in almost all
the manufactories and workshops of the United States, no matter