difficulty, and the advantages on this
side are certain to increase rather than to diminish during the next
few years.

The electric rock-drill, which can already hold its own with that
driven by compressed air, is therefore bound to gain ground in the
future. This is a type and indication of what will happen all along
the industrial line, the electric current taking the place of the
majority of other means adopted for the transmission of power. Even in
workshops--where it is important to have a wide distribution of power
and each man must be able to turn on a supply of it to his bench at
any moment--shafting is being displaced by electric cables for the
conveyance of power to numerous small motors.

The loss of power in this system has already been reduced to less than
that which occurs with shafting, unless under the most favourable
circumstances; and in places where the works are necessarily
distributed over a considerable area the advantage is so pronounced
that hardly any factories of that kind will be erected ten years hence
without resort being had to electricity, and small motors as the means
of distributing the requisite supplies of power to the spots where
they are needed. It was a significant fact that at the Paris
Exposition of 1900 the electric system of distribution was adopted.

In regard to compressed air, however, it seems practically certain
that, notwithstanding its inferiority to electric storage of power, it
is applicable to so many kinds of small and cheap installations that,
on the whole, its area of usefulness, instead of being restricted,
will be largely increased in the near future. There will be an advance
all along the line; and although electric storage will far outstrip
compressed air for the purposes of the large manufacturer, the air
reservoir will prove highly useful in isolated situations, and
particularly for agricultural work.

For example, as an adjunct to the ordinary rural windmill for pumping
water, it will prove much more handy and effective than the system at
present in vogue of keeping large tanks on hand for the purpose of
ensuring a supply of water during periods of calm weather. Regarding a
tank of water elevated above the ground and filled from a well as
representing so much stored energy, and also comparing this with an
equal bulk of air compressed to about 300 pounds pressure to the
square inch, it would be easy to show that--unless the water has been
pumped from a v