in two or three
days, a stove should be put into the room in order to facilitate the
process. The greatest care, however, must be taken in the use of
artificial heat. The whole apartment should be kept of one equal
temperature, which ought never to be higher than is requisite to dry
the hose for greasing in about forty hours.

_Coupling-joints._[O]--So much of the efficiency and duration of the
hose depend on the proper form given to the brass coupling-joints,
that I deem it useful to give a detailed description, both of those
generally made use of and of those adopted by the Edinburgh
fire-establishment, and also to point out their various defects and
advantages.

[Illustration: FIG. 3. Old Coupling]

Fig. 3 is the construction commonly made by engine-makers. Its defects
are as follows:--From the form of the furrows and ridges where the
leather is tied it does not hold on well against a force tending to
pull the hose off end-ways; screw-nails are therefore often employed,
as at A, to secure the hose on the brass. The points of these nails
always protrude more or less into the inside of the joint, and
materially impede the current of water. The mouths of the joints are
also turned outwards, and form a shoulder, as at B. The intention of
this is probably to assist in securing the leather in its place, and
to prevent the lapping from slipping. The effects of it are as
follows:--First, from the leather being strained over this projection,
it becomes liable to be cut by every accidental injury, and very soon
cracks and gives way, when a portion must be cut off and a fresh
fixing made; second, the leather being stretched over the projection,
does not fit the other part of the joint, and must be loose or filled
up with pieces of leather, or, as is sometimes done, with brown paper;
third, the irregularity of the calibre of the conduit which this
shoulder occasions diminishes the performance of the engine.

[Illustration: FIG. 4. New Coupling]

Fig. 4 is the coupling-joint adopted in Edinburgh. The furrows at the
tying place are shallow, but their edges present a powerful obstacle
to the slipping of the leather. No screw-nails are employed, nor is
there any shoulder, as at B; there is therefore no impediment to or
variation in the velocity of the current, as the calibres of the
coupling joints and of the hose are so nearly uniform. It will be seen
also that as the lapping projects above the leather this latter can
never