The evening times., 1911-08-09
MAKING THE sun
WORK FOR FARMER

day TO day would be found IL We
could make measurements in free
space. outside the earth's atmosphere
altogether.
We have tested this conclusion by
every means in our power; but there
is one test not in our power to ap-
ply. which would be worth all of the
other tests put together, and that test
IT, TO. be brought about by putting an
other branch station in the cloudiess
region Of southern Mexico 80 az to
| observe the sun there simultaneously
with the observations made upon
Mount Wilson.
IL the two sets of observations
agree, the conclusions would be prov
ed and we shall have made discov-
cry OF the first rank; for we will
know that II the sun varies the temp
erature OF the earth must vary also,
and the relationship will be so i'm
portant 70 the weather bureau that
undoubtedly the work we are doing
| will be continued daily at several sta
tions all over the world
In line with this are the expert
! nehts now being carried on by the
department OF agriculture, based on
DR.. AbDot's observations.
THE agricultural department is
now getting interested in questions
OF the amount and quality of radia-
tion Of the sun. in connection with
their bearing on the growth OF crops" :"
says Or. Abbot, in discussing the
practical phase Of the work of the
agtrophygical observatory. 1T is
found that it is not necessary to have
the whole output OF the sun as re-
ceived cugtomarily, but that a frac-
tional part would be sufficient for the
proper growth Of crops.
THE question then is, which part
is best for certain vegetation? Is it
the green rays or the blue or invisi-
bic: Or are some parts even harm
full? For such experiments as this
our measurements Of the amount of
radiation of the different colors are
very desirable and even highly neces-
sary.
To Measure Radiation.
"Dr. Lyman ]. Briggs Of the agri-
cultural department is experimenting
On certain apparatus to be put in the
hands Of the farmers for the pur-
pose OF measuring the amount OF rad
iation actually received at the earth's
surface. Tits. taken In conjunction
with our measurements of the suns
radiation, should be OF great value
for agricultural purposes.
"As another instance Of the prac-
tical uses OF the the studies We are
making ! might point to the assist
ance we have rendered to the engi-
neering corps Of the army, which
wished to get information in regard
to the weakening Of the arc light
when seen at sea. as bearing on the
different appearances Of the arc
lights with respect to coast defenses;
what 1t would be at one mile, two
miles. or any visible distances. For
that purpose they Wished to know the
weakening Of each color by itself.
Our observations OF losses which
light suffers in passing through the
air gave them the Information they
desired, the values we gave being
based entirely on our observations at
Mount Wilson and Washington"
DR.. Abbot has reached the present
point in his efforts to determine as
a scientific fact that the radiation OF
the sun varies after eight years Of
persistent work; and as this work is
not being duplicated at any other OBJ
servatory in the world, his investiga-
tions and the coming expedition to
Mexico are being watched with un-
usual interest by astronomers both in
this country and abroad
II was In 1903 that DIR. Abbott not
ed fall of solar radiation of about