The Locomotive - Lighthouse Survival Blog

154 THE LOCOMOTIVE. [October,
tion of the heat produced into various forms of mechanical euergy lias gone on for a
hundred years, increasing in magnitude at a rate which is almost bewildering, creating
conditions of which few persons grasp the full significance, and affecting the whole
human race in its relation to its environment more profoundly than any other event in
ils history.
The nature of the changes thus wrought is well known among intelligeut persons,
but their extent is so little appreciated that it will be useful to- consider, briefly, that
phase of the subject, and especially to endeavor to present it in such a way as to empha-
size the purely power aspect of the question.
Everybody has a more or less correct idea of the enormous development of steam
navigation and railway systems and of the cheapening of transportation brought about
by it; of the phenomenal growth and widespread distribution of manufacturing estab-
lishments; of the generation and use of electricity as a convenient means of transmitting
energy: and of many other things characteristic of the industrial revolution through
which we are passing. It is instructive, however, to reduce it all to the daily combus-
tion of a certain, rapidly increasing number of pounds of coal, for these may be easily
converted into their muscle equivalent. And since by far the greater part of the coal
out put goes directly or indirectly into the production of power, no attempt will be
made to separate from the whole that which is used purely for heating purposes, and
indeed, the very general consideration of the subject to which this discussion must be
restricted does not require such separation. Furthermore, for convenience in under-
standing numerical relations, it, may be assumed that the combustion of one pound of
coal under the favorable conditions of modern practice produces available energy equal
to the work of one horse for one hour, and that a horse-power is equal to the power of
seven men.
The total quantity of coal taken in any given year from the mines of the whole
world cannot be very accurately ascertained, but from the best, available information it
may be assumed to have been about 700,000,000 tons of 2,000 pounds each for the year
1900, the la