advantage is that, like a ram, the windmill may work night
and day, with but slight attention to lubrication, so long as the wind
blows. But there are also drawbacks; it requires very large storage
tanks to provide for periods of calm; the wheel must be placed
sufficiently exposed to receive the full wind force, either on a tower
or on a high hill, and usually this is not the best place to find
water. Besides, a windmill tower, at least the modern one, is not an
ornamental feature in the landscape. It is expensive when built
sufficiently strong to withstand severe winter gales. During the hot
months of the year, when the farmer, the gardener, and the coachman
require most water, the wind is apt to fail entirely for days in
succession.

_The Use of Engines_

If water is not available, and wind is considered too unreliable,
pumping must be accomplished by using an engine which, no matter of
what form or type, derives its energy from the combustion of fuel, be
the same coal, wood, charcoal, petroleum or kerosene, gas, gasoline,
or naphtha. The use of such pumping engines implies a constant expense
for fuel, operation, maintenance, and repairs. In some modern forms of
engines this expense is small, notably so in the oil engine, and also
in the gasoline engine; hence these types have become favorites.

_Advantages of Pumping Engines_

An advantage common to all pumping engines is that they can be run at
any time, not like the windmill, which does not operate in a light
breeze, nor like the ram, which fails when the brook runs low.
Domestic pumping engines are built as simple as possible, so that the
gardener, a farm hand, or the domestic help may run them. Skill is not
required to operate them, and they are constructed so as to be safe,
provided ordinary intelligence is applied.

In using a fuel engine it is desirable, because of the attendance
required, to take a machine of such capacity and size that the water
supply required for two or three days may be pumped to the storage
tank in a few hours.

_Expansive Force of Heated Air Utilized_

A favorite and extensively used type of domestic pump is the hot-air
engine, in which the expansive force of heated air is used to do
useful work. Among the types are simple and safe machines which do not
easily get out of order. They are started by hand by giving the fly
wheel one or more revolutions. If properly taken care of they are
durable and do not require expensive