supply, not only to store the water in sufficient bulk at such
a level that it can be usefully employed, but also to lead it
to the power-house, and then to provide for its escape after it
has done its work. The power-house, with its turbines and other
machinery, involves a comparatively large outlay, but if the
pump can be directly driven from the turbines, so that the cost
of attendance is reduced to a minimum, the system should
certainly receive consideration.

Although the wind is always available in every district, it is
more frequent and powerful on the coast than inland. The
velocity of the wind is ever varying within wide limits, and
although the records usually give the average hourly velocity,
it is not constant even for one minute. Windmills of the modern
type, consisting of a wheel composed of a number of short sails
fixed to a steel framework upon a braced steel tower, have been
used for many years for driving machinery on farms, and less
frequently for pumping water for domestic use. In a very few
cases it has been utilised for pumping sewage, but there is no
reason why, under proper conditions, it should not be employed
to a greater extent. The reliability of the wind for pumping
purposes may be gauged from the figures in the following table,
No. 11, which were observed in Birmingham, and comprise a
period of ten years; they are arranged in order corresponding
with the magnitude of the annual rainfall:--

TABLE No. 11.

MEAN HOURLY VELOCITY OF WIND