The visible escape of the steam is prevented by superheating. To effect
this, the steam, as it leaves the cylinder, passes into a cast iron
chamber adjacent to the boiler, which is intended to retain the water
carried off with the steam. From thence the steam passes into a second
chamber, suspended at a small height above the grate in the axis of the
boiler and of the flue which conveys the heated gases into the chimney,
and thence into a sort of pocket inclosed in the last-mentioned chamber,
which is open at the bottom, and the upper part of which terminates in a
tube passing into the open air. This method of dissipating the steam
avoids the necessity of a condenser; but if it be admitted that the steam
in escaping has a minimum temperature of 572 deg. Fahr., it will carry away
12 per cent. more caloric than would have been required to raise it to a
pressure of 150 lb. per square inch.

The steam escaping through the safety valve is passed through the same
apparatus.

The toothed wheel on the driving axle is arranged to act upon another
toothed wheel on a shaft connected with the regulator, so as to control
its speed automatically.

The length of the engine is 10 ft. 10 in., its width 5 ft. 9 in., and the
distance from center to center of the wheels 5 ft. 2 in.

The Rowan tram-car consists of a body 31 feet long and 7 feet wide,
resting on a two-wheeled bogie behind and on a four-wheeled bogie in
front, this front bogie being the motor, and the whole has the appearance
of a long railway carriage, somewhat in the form of an omnibus with a
platform at each end, of which the front platform is occupied by the
engine. It requires, therefore, either a turntable or a triangle at the
end of the line, so as to enable it to reverse its direction.

This motor is a steam engine of light and simple form, supplied with
steam from a water tube boiler with very perfect combustion, so that no
smoke escapes. The boiler is somewhat on the principle of a Shand and
Mason boiler; it is so built that It can easily be opened and every part
of the interior examined and cleaned.

The peculiarity of the Rowan motor is the simplicity of the attachment of
the engine to the carriage, and the facility with which it can be
detached when required for cleaning or repair, viz., in five or six
minutes.

The steam can be got up in the engine with great rapidity if a change of
engine is required. When, however, the engine is detached, the carriage