The Fulton County news. [volume] (McConnellsburg, Pa.) 1899-current, 1901-09-19
Stellar Heat Radiation.

<hS IL ~ were uobtuouSll w nave
measured the enormous distances
of those few stars whose paral-
lakes are determined by triangu-
lation upon the only available base
line of the diameter of the earth s
orbit, and later to have discover
ed by means of the spectroscope
the general constitution of many
suns, together with the rate and
direction of their motion, astro-
physicists propose to ascertain
the quantity of heat they radiate
to the earth across the immense
spatial abyss. In this connection
Professor Ernest f. Nichols, of
Dartmouth College, has recently
contributed a new and interesting
chapter to the story of the heav-
ems.
So long ago as 1869 Sir William
Huggins, the eminent English
physicist, attempted this particu-
lar investigation, and published
the results he thought he had Sc
cured with his thermopile and
galvanometer, and the following
year his conclusions were prac-
tically corroborated by so well
equipped an investigator as DR..
E. j. Stone; however, astrono-
mers in general were disposed to
attribute the disturbances of the
extremely sensitive apparatus
employed to extraneous and acci-
dental causes, and this suspicion
apparently received confirmation
in the utter failure of Professor
G. V. Boys, of Oxford, in 18S8-90,
to observe the slightest indication
of stellar heat radiation with his
radiomicrometer-an instrument
of such intrinsic sensitiveness
that without the aid of concentra-
ting mirrors and lenses it exhib-
tied a detection of 60 nm. when
a candle was placed at a distance
of inches, and when in conjunc-
tion with a reflector of 16 inches
aperture showed detection of
3S nm. produced by the heat of a
candle at distance of $50 yards,
being fully capable of detecting
so minute a degree of heat as
1-150,000 of the amount radiated
by the full moon to the mirror.
Notwithstanding this circum-
stance, the American electrical
genius, Edison, believed that with
his micro-tasimeter he succeeded
in detecting heat waves coming
from the star Arcturus, but this
now seems quite improbable, be-
cause of the comparatively small
capacity of his apparatus.
Professor Nichols's expert.
ments, which were carried on at
the Yerkes Observatory, with the
aid of thoroughly qualified assist
ants, were made with his torsion
tiny, air tight case
with a huorite window, contain
ing a suspension of quartz fibre,
with vanes of mica but 3 nm. in
diameter, coated with lampblack.
The Yerkes "a inch silvered glass
mirror, fashioned by Mr.. G.
Willis Ritchey, was employed to
collect and supply the starbeams
and the reflections were read at
a distance of several feet with a
telescope. The full description
of the apparatus, with the min
uties of the experiments as pub
lished in the Astrophysical Journ-
al would occupy more than a page
but it is sufficient to state that
the radiometer is at least twelve
times as sensitive as Boys radi-
omicrometer, which would indi-
cate the one one milllonth of a
degree rise in temperature.
Two well known stars, Arctur-
US and Vega, respectively prob
ably $50 and 1000 trillions of miles
distant from the earth, and plan
cts, Jupiter and Saturn, were
selected for the experiment. All
heprocesses involved were dainty |
and arduous, and as usual, mech.
anical and atmospheric difficulties
supervened, but the investiga-
tions was highly successful, and |
the average Of the observation, ex-
pressed in terms of many million