The Bennington evening banner. (Bennington, Vt.) 19??-1961, 1915-03-20
HEAT HEAT Of OUR Z sun
To Measure 1t Is a Perplexing
Problem For Science.
NEWTON ONCE TRIED TO DO IT
He Figured It at the Amazing Intensity
= of 1866, 300 Degrees Centsrade, While
the --latest Estimates Place IT at
About $500 Degrees. B 81.

= OF 1,669, 300 Degrees Centigrade, Whiie
the Latest Estimates Place II at
About $500 Degrees. Il,
How hot is the sun? The question
has been answered in many different
ways, and it is by no means certain
that we have yet arrived at an even
approximately accurate answer. Yet
1t would Seem that as the sun Is the
only source of the earths heat, and
rs we know the exact distance of the
sun, it ought to be easy TO calculate
his heat. That is what Newton thought
in 1850 when, finding that thermom-
eter registered 65 degrees c. in the
sun and 29.44 degrees c. in the shade.
and applying the law of the square OF
distance Lx announced that the suns
neat was 1,669,300 degrees c.!
In 1897 Sir John Herschel and Pouil-
let devised special instruments for
measuring the solar heat, but at the
very beginning disagreed on funda-
mental question. Pouillet wanted to
estimate that the eartl's atmosphere
cut off half the suns heat; Herschel
insisted that it cut off only one-third.
Herschel reached the conclusion that
the suns heat was two calories per
square centimeter per minute. Pouil-
let calculated it at 1.7G33 calories per
square centimeter per minute. This
means that the suns rays falling YER
tically upon each square centimeter OF
the earth's surface would be sufficient
~ powerful, il it were mot for their
absorption by our atmosphere. TO raise
1858 grams of water one degree G.
per minute. This number is what as
tronomers call the solar constant
Pouillets figures, II, were generally
accepted until recently. Forbes by ex-
periments at the top and ut the base
of high mountain calculated that 2.s5
was the correct number. Wolfe made
it 2.54, and Croya asserted that it was
certainly superior TO two calories per
square centimeter per minute.
The American Langley invented the
bolometer, by means of which he
measured the intensity of each ray by
the length OF its wave before entering
our atmosphere. Thus lie proved that
the rays of shortest length are those
that are nloSt absorbed. 1t Is as if we
placed two red glasses between our
selves and the sun, one. representing
the suns atmosphere and one repre-
senting our own. b
~.
The Able Moreux, director of tho
,Boirges observatory declares in III
article in Cosmos that If these two at
mospheres We're eliminated, and we
could see the sun as he really is he
would appear to be a brilliant greenish
blue. s4''ft ---.li, tir
n. Langley's calculations placed the so
lar constant at about' three. Helproved
that scarcely G0 per cent of the SUMS
rays penetrated TO sea level. gl
Other Observers obtained other tig,
ires, and at the beginning OF this cen
tury the tendency was to return to
those announced by Herschel and
pouillet
1t Is certain that the earth intercepts
only about one twobilliohth part OF
the actual heat of tile sun, but IL we
adopt langley's figure, 3. we find that
the fraction OF heat received would be.
sufficient 20 melt annually layer Of
ice 222.7 - feet thick at the equator OF
the earth. The average power receiy
ed from the sun over the entire earth
is equal TO 15t464.O00 kilogrammeters
n year, or one continuous horsepower
for every 1.72 square meters.
The greater part Of this heat is used
up in keeping the earth warm; but, ac-
cording to Helmholtz, about Il thou
sandth part of it is absorbed by ami
mails and vegetables and becomes I'm
abundant reserve Of energy for the
human race.
If we accept the more recent figures.
of Messrs. Abbott, Fowle and Aldrich
at the Smithsonian institution in
Washington and cali the solar constant
two calories per square centrneter per
minute, the results are scarcely less
striking
If the total heat could be applied to
n block of ice at o degrees G. as thick
MS the earth--S,00O miles-this would
be entirely melted in quarter OF an
hour. All the water thus obtained
would be turned TO steam at 100 de-
grees c. III minutes later. the whole
operation from ice to steam having
taken only two hours and twelve min
utes.
The most recent estimate of the tenn
r,nrn it1rn nf il,n -nn's SIrfnon il hp-