The Locomotive - Lighthouse Survival Blog

1901.
J
THE LOCOMOTIVE. 157
It is interesting to note that while the energy of ordinary water power is due
ultimately to the heat of the sun, by which water is continually carried from a lower to
a higher level, that of the tidal wave is dependent upon the rotation of the earth upon
its axis. The earth may be regarded, mechanically, as a huge fly-wheel of enormous
mass, its mean density being not materially less than that of iron, which, in some way or
other, has been set spinning about its axis and is thus a storehouse of energy, the amount
of which is practically inconceivable. The effect of drawing upon this supply would be
to lessen the speed of rotation if there were no compensating influences; that is to
increase the length of the day. Of the immensity of this source of power it is almost
impossible to form an adequate conception. If it could be tapped successfully it might
be drawn upon indefinitely, and every demand might be satisfied without serious dis-
turbance of the solar system.
Great, also, beyond our power of calculation, is the stored energy of the interior
heat of the earth, and some not entirely unsuccessful attempts to utilize this have already
been made. From a short distance below the surface the temperature increases downwards
at an average rate which indicates that at a depth of fifty miles it is not less than
5,000° Fahr., and there is abundant reason for believing that the earth is an intensely
hot body with only a thin layer of poorly conducting, cold surface matter. These are
the essential conditions of a heat engine of enormous capacity, and as in many parts of
the world comparatively high temperatures are found very near the surface, while in all
parts considerable ranges are possible within reasonable differences of level, the interior
heat of the earth is worthy of most serious consideration as a possible and reasonable
source of power. Its importance will be greatly enhanced when we are able to transform
heat energy directly into electricity on a large scale and with economy, avoiding the
great waste which necessarily accompanies the use of
soon come about.
the steam-engine; and this must
The power by which, for the most part, the work of the world will be done durino-
the next few centuries must come, it is believed, from one or more of the sources here
considered. They are none of them fanciful; all are, even in the present state of science
and art, within reach, and in capacity they are sufficient to satisfy any conceivable future
demand. The abandonment of fuel as the chief source of energy is sure to come- its use
is accompanied by many well recognized and harmful disadvantages, and it is not improbable
that the time will come when men will look upon the era of coal much as we
now look upon the Stone Age of our ancestors. — T. C. Mendenhall, in Cassier's Maga-
zine.
A Venerable Engine. — The Illustrated Guide, published in connection with the
exposition at Glasgow, Scotland, says that there is at the Farme colliery, Rutherglen,
near Glasgow, situated about a quarter of a mile from Dalmarnock Bridge, and within
ten minutes' walk of Rutherglen Station, an "atmospheric" or Newcomen engine,
which has been at work drawing coal since it was erected in 1809. The cylinder was
never bored and is open at the top, and the piston is packed from time to time with
hemp, which, with a little water at the top, keeps it sufficiently tight, and it gets an
occasional scrape to keep it in order. It takes about 35 seconds to lift coal from the
bottom of the pit to the top. A man work3 the handle which admits steam to raise the
piston, and, alternately, water to condense the steam under the piston, so that the
weight of the atmosphere may press the piston down. With the exception of one or
two spur wheels, which were broken by accident, no part of the engine has been renewed.
It is the oldest engine at work in Scotland, and the only "atmospheric"