What unused energy still awaits utilization by man is indicated in the
following calculation:
The tremendous amount of energy received from the sun may be
illustrated in another way. Ordinary steam-engines, whether
for railroad or factory use, are rated by their horse-power; a
hundred-horse-power engine will drive a small steamer or operate
a mill of some two hundred and fifty looms. Now, thirty calories
of heat per minute, if completely utilized, would produce 2.8
horse-power. Neglecting atmospheric absorption, therefore, each
square meter of the earth’s surface receives from the sun, when
directly overhead, sufficient energy to run a 2.8 horse-power
engine; or one horse-power is received for every four square
feet of surface. The absorption of the air cuts this down about
forty per cent, so that on a clear day at sea-level, with
the sun directly overhead, sufficient energy to produce one
horse-power is received on each six and a half square feet of
surface.--CHARLES LANE POOR, “The Solar System.”
(914)
See MOMENTUM.
=Energy, Economy of=--See ECONOMY OF ENERGY.