Evening capital news. (Boise, Idaho) 1901-1927, 1916-10-22

A FTER three-quarters of century
n Of experiment science has virtual
= ly solved the problem of harness
ing the sun directly to the wheels that
do the worlds work. AS everybody
knows, the solar centre of our universe
Is the indirect source OF all the mechani-
cal power developed for mans service.
Wood and coal are products of the suns
action upon the soil. Used as fuel, they
produce steam. and steam drives our
engines.
In another respect the sun is an in
direct source OF our mechanical power.
1t draws water from the ocean, keeping
the rivers flowing, and where there are
waterfalls powerful wheels are turned
without the Intervention Of steam. So.
Just as coal Is aptly called bottled sun
shine" waterfalls are called, white
coal"
But coal, in civilized lands at least, is
no longer being produced by the sun.
and wide cultivation of the soil, thus alb
sorbing most Of the annual rainfall, is
drying up the streams and more and
more limiting the supply of water power.
The great coal beds produced by
millions Of years of sunshine and pre-
served by geological upheavals are
rapidly being exhausted by humanity's
voracious demands upon them. The case
is the same with the twin sister of coal
petroleum A few more decades and
the supply will be exhausted.
In view of these demonstrated facts
proceeded with various plans to in
duce the sun to give to us day by day
the power we need, which formerly 1t
stored in the earths crust. Steam
pressure Is still the medium, with the
direct action Of the sun upon water to
convert It into steam.
,The principle employed is the IA
miliar one of the burning glass;" which
produces an intense heat by focusing
the suns rays upon a small point. Theo-
retically, it is a simple problem In arith-
metic to determine what degree Of heat
will be produced by the concentration of
given area of sunshine upon another
smaller area, and how much power
should result. Writing on this subject
THE Utilization of Solar Energy
A. S. e. Alderman, B. &c., says:
"The glowing surface which the sun
presents to us, even considering him as
fiat disk, has the. enormous area of
bS5, 100000 square miles, each square
foot OF which emits the enormous
amount Of about 1880 horsepower, and
the radiant energy received at the outer
surface of the earth's atmosphere Is
equivalent to 1900 horsepower per acre.
OF this about 70 per cent (say 5000
horsepower per acre. is transmitted to
the land surface of the earth at. noon on
clear day, and less in the morning and
evening, owing to the greater thickness
OF atmosphere through which the radia-
ton has to pass.
Now, although the theoretical power
value Of the heat reaching the surface
OF the earth is no less than 5000
horsepower per acre, it must not
be thought that anything like this
amount can be converted into me-
chanical power any more than can all
the heat of coal be converted into its
theoretical equivalent OF mechanical
power. For example, the heat value of
good coal is about equal to 1880 horse
power hours per ton, but in fact the best
result, even under test conditions. ever
obtained from ton of coal by means of
o boiler and steam engine is only 1.47O