The Providence news. (Providence [R.I.]) 1891-1906, 1899-10-09
THE TEMPERATURE OF THE SUN.

The temperature Of the sun has been
held Of late years To be probably BE-
tween 5000 and 5000 degrees ccntigrade.
this being tha result obtained from a
careful investigation made by Messrs.
Wilson and Gray in 1898. Recently Pro-
fessor Wilson has conducted what may
be considered in supplemental investi-
cation OF Radiation from a Perfect
Radiator" an account Of which is given
in the Astrophyslcai Journal. which
has led him to conclude that his former
figures were too low, and he now gives
1900 degrees cenugrade, instead of
500 as more probably Inc suns "effec-
tive temperature
This temperature can be ascctiained
of course, only from a study OF the ef-
ticiency OF the suns heat at our dis
tance from II of about 92, 100 600 miles.
or. i'm ether words. from the power of
the suns heat radiation at the earth's
! surface, and In order to work out IN
problem from this easily-ascertained
datum IL is necessary to know the law
OF heat radiation from perfect ra-
diator,' which the sun Is assumed To
be. lt may easily be found by expert
ment that the rapidity with which "A
hot body cools, or i'm scientific phrase
ology, radiates It's heat, varies greatly
with the 4 mperature of the body 4
very hot body cools much faster than
onH at a lower tempera ture. But only
aiter long series OF carefully conduct
ed experiments has the law of this va.
RATION be y made out. at lelst approx -
imateiy. Wilson and Gray found that
the radl@tton is very nearly proportion-
"A Ia & 81
turc conclusion which viii be Greek
20 the unsCcntihc read r. but which
can he Illustrated thus: III body at A
Ccrtain temperature say Too degrees
ccnigradc throws TO "a certain distance
from II certain amount of warmth
which may be measured by means OF
some one of tha delicate heat dctecfors
now in use-the same BODY raised to a
temperature OF 200 deEr es win AFFECT
the instrument. not twice as much. but
sixteen times as much, sixteen being
the fourth power OF 'tNNO. or 90 cfyc an
other Illustration II IN suns temDera
turc were 90 be doubled the potency ~
the heat rays upon the earth would be
sixteen times as great as ~ now is. and
were % 90 be trehlcd thc heat which Wa
should then receive from the sun would
be eighty -One times as great as now.
lgn0vanCc of this law was one rcason
why che earlier lnvesti gators 81 IN.
sun temperature made tt ont 10 be
vastly higher than 10 probably is
Father Secchi estimated it in millions
of degrees. ana 9th scientists made n
tens ~ th0usln ls of degrees.
The method pursued by Wilson and
Gray in thcir investigation was FIRST
Il study the law of radiation from "a
platinum "trip. which was raised 10
any desired temp rature by an electric
current ana the radiation coming from
which then balanced the radiation conn
ing from tho sun tho balancing instrti-
inem being duplex Rows tndin-rnIrro-
meter. esp cially q signed FOR this
work 10 was assumed that the radia-
bon from this strip was only thirty
I've hundrc this ~ that from a "pcr
'ect radiator" Professor Wilson nov.
hinks this to have been an orror-thaf
he radiation was nearly rfect Hence
lis correction Of tha result then oh
alned.as above stltod-ii 200 q graes as
he suns temperature. instead or 5000
2 grrpa