Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1916-05-15

experiment OF trying to make a plant
grow twenty-four hours day by ex-
posing it to electric light at night was
tried not long ago by scientists Of
tho Department OF Agriculture. Had
1t been success. wonders might have
been accomplished in the rapid pro-
duction OF food crops. nation at
war, Tor example. would have been able
TO double the productivity OF It's soil.
All OF these large possibilities were
nipped In the bud. The plant grew
with abnormal rapidity for a time. and
then 1t got sick. Even though the
same amount OF light and heat were
supplied by electricity at night as the
sun afforded during the day the plant
could not grow healthily without sun
light.
This experiment shows that solar
radiation-Quite apart from the tenn
pcrature 1t produces--is an essential
to plant life: yet it is the one element
in tho climate which has not been
closely studied recently. Temperature
wind. rainfall and all of the other
things that go to make up weather
nave been carefully observed and
chartered You can write to tho
weather bureau and ask them about
the climate Of almost any township in
the United States and they will give
In exact figures. The only thing they
cannot tell you is the amount of solar
radiation received by that particular
township, unless you live In one OF four
places where Investigations Of solar
radiation are being carried on
Grent Agricultural Factor.
When these Investigations have been
made In all parts OF the United States.
one more element in climate, one more
factor in agriculture. will have been
chartered and put TO intelligent use
a real step forward In the control Of
man over nature will have been taken
1t IS known, for example, that in
countries where solar radiation is
strong, sugar heets yield a far higher
percentage OF sugar in proportion to
their bulk. This suggests that solar
radiation is an essential element in the
conversion of starch into sugar with
In tho plant.
This study OF the SUMS energy also
opens another fascinating possibility
that OF putting the sun TO work The
construction of a practicable motor
which would use the heat of the sun
would solve the power question for
ever. The price OF gasoline would
worry us no longer. Power would he
free and inexhaustible
The problem is particularly TEMPT
ms, because II can easily he solved
on small scale. Any one can build
a sun motor that will turn a little
wheel. and in Southern California one
was constructed with a concave mir
ror surface, which focused the rays of
The sun so as to develop n considera bile
power. 1t was not. however, CONNER
cialiy practicable. The secret OF how
to capture and concentrate the heat OF
the suns rays remains unsolved Sci
entihc observation. however. may
show the way. Or. KimbaIl, who is
conducting the Investigations at WASH
ington. recently discovered, quite by
accident. that when an electric-lieht
bulb is exposed to sunlight the fla
ment quickly attains Temperature
above boiling. This suggests that a
large glass vacuum filled with fila
ments might capture and store the
SUMS energy in disable quantities. The
idea is offered to inventors, for what
1t may be worth.
Making Accurate Observations. I.
Studies Of solar radiation are now
being carried on by the government
at four points-Madison, wis; Lincoln,
Neb.; Santa Fe, n. NJ, and Washing
ton. d. G. Observations are made of
the amount of heat that a given area
receives from the sun, and of the
amount that is radiated from the earth,
under all conditions and at all times
OF the year. This information is &C
curately charted for a number of years,
SO that by referring to the chart you
can determine, for example. Just how
much solar radiation your garden
ought to receive during the first week
In June.
Separate observations are made of
the amount Of light afforded by the
sun; the direct light and that reflected
from clouds and the earth being care
fully distinguished.
The Investigations OF the suns heat
are made by a pyrheliometer, which
OF perfection. It's principle is simple.
sorb the rays Of the sun is exposed
building. This plate is connected by
wires with resistance" in an electri-
cal circuit I'm the laboratory In ac-
cordance with well-known electrical
law, the heat increases this resistance,
thus affecting the current, which
actuates pen. Thus the variations
OF temperatures are accurately record
ed In the course Of a line.
The mea suroment OF the heat that is
radfated from the earth is OF far moro
Importance than you would suspect;
for 1t is chiefly this second" heat that
warns our atmosphere. All heat trav-
els In waves. The SUMS heat reaches
tho earth In very long wave-lengths.
which penetrate the atmosphere and
are absorbed by the earth. Later the
heat Is radated out again in short
wave-1engths which are held by the
atmosphere.