disadvantage of an engine is, that it requires a
considerable number of men; but even the proof, that of throwing the
water to a given height on the gable of a house or other height, is
not always a test of the sufficiency of the hose. As the temperature
is low or high, the wind fresh or light, the degree of pressure on the
hose in throwing the water to the required height will be greater or
less. Indeed, in high winds it is a matter of extreme difficulty to
throw the water to any considerable height.

With an engine of 7-inch barrels and 7-inch stroke, fitted with eighty
feet of 2-3/8-inch hose, I have found from several experiments that
when the water is thrown seventy-five feet high, the pressure on the
hose is equal to one hundred feet. The same engine, with 160 feet of
hose, and the branch-pipe raised fifty feet above the level of the
engine, when the water was thrown fifty-six feet from the branch,
occasioned a pressure equal to 130 feet on the hose. From these
experiments, I am convinced that the pressure will not be equal to 200
feet, except in very extreme cases, or when some obstacle gets into
the jet pipe.

I tried the extreme strength of a piece of riveted hose 4 feet long
and 2-3/8 inches diameter, and found that it did not burst till the
pressure increased to 500 feet; and when it gave way the leather was
fairly torn along the rivet-holes.

Every possible care should be taken to keep the hose soft and pliable,
and to prevent its being affected by mildew. After being used, in
order to dry them equally they should be hung up by the centre, with
the two ends hanging down, until half dry. They should then be taken
down and rubbed over with a composition of bees'-wax, tallow, and
neats-foot oil,[N] and again hung up to allow the grease to sink into
the leather. When the hose appear to be dry they should be a second
time rubbed with the composition, and then coiled up for use. In order
that the hose undergoing the operation of greasing may not be
disturbed or used till in a fit state, it is better to have a double
set, and in this way, while one set is in grease the other is in the
engine ready and fit for service. More time can also be taken for any
repairs which may be necessary, and they will in consequence be more
carefully done, and at fires where a great length of hose is required
the spare set will always be available. When the weather is damp, and
the hose cannot be dried so as to be fit for greasing