in situations where the engine is exposed to frost.

The valve-covers are of cast-iron, fastened down with copper screws, a
piece of leather or india-rubber being placed between them and the
upper edges of the sole.

The pieces at each end of the sole are of cast-brass, instead of
sheet-copper, with soft-solder joints, which are very apt to give way.

The screwed suction cap with iron handle admits the water in two
different directions, according as it is open or closed: the one to
supply the engine when water is drawn from the cistern, the other for
drawing water through the suction-pipe.

The valves are brass plates, truly ground to fit the circular brass
orifice on which they fall. The brass being well ground, no leather is
used for the purpose of making them tight. The longer they are used
the better they fit, and by having no leather about them they are less
liable to the adhesion of small stones or gravel. The whole valve is
put together and then keyed into a groove in the sides and bottom of
the sole, left for that purpose.

The barrels are of cast-brass, with a piston made of two circular
pieces of the same metal, each put into a strong leather cup, and
bolted to the other. The bottoms of the cups being together, when the
piston becomes loose in the barrels, and there is not sufficient time
to replace the cups by new ones, they are easily tightened by putting
a layer of hemp round the piston between the leather and the brass.
This operation, however, requires to be carefully performed; for if
more hemp is put into one part than another it is apt to injure the
barrels. The barrels are fixed to the cast-iron sole by copper screws,
a little red lead being placed between the bottom flange of the barrel
and the sole.

When the engine is likely to be dragged over rough roads or causeways,
it is of importance to have it set on springs, to prevent the jolting
from affecting the working part of the engine, everything depending on
that being right.

The engines used in Paris are mounted on two wheels, the carriage and
the engine being separate, the latter being dismounted from the former
before it can be used. In Paris, where the engines are managed by a
corps of regularly-trained firemen, this may answer well enough; but
if hastily or carelessly dismounted by unskilful persons, the engine
may be seriously damaged. It is also worthy of remark, that the proper
quantity of hose, tools, &c., can be more easily attac