The true northerner., 1873-05-30
THE HEAT OF THE SUN.

Every great extension of scientific
knowledge opens new fields for specula-
ton. The new facts lead to new fancies.
From each height greater heights ap-
pear The solution of one problem
brings others into view.
1t is not many years since the grand
doctrine of the conservation of energy
became recognized as one of the funda-
mental truths of science. Philosophy
had half realized that force could not
be created, but the experimental proof
was wanting. 1t remained for RumfOrd
and Davy, Mayer and Joule, Helmholtz
and Clausius, to place the doctrine fairly
upon its feet as one of the mightiest
facts of the universe. It's establishment
revolutionized some departments of
thought Theories about mysterious
fluids and imponderable agencies were
banished forever from the domain of
physics. And men were soon taught to
look upward to the sun as the main
source OF all the active, physical energy
which makes the earth habitable
planet. Wenow know that, without the
suns light and heat, no life could exist
on earth. Not breath could be drawn,
not motion made, not flower develop
from its seed. The wind, the currents
of ocean, the evaporation of water, the
formation of rain, hail, and snow, all
would cease. Earth would become a
dead and dreary waste. The very rivers
would no longer run, and the seas would
be frozen solid. What subject, then,
could be more fruitful of speculations
than the sun? It's heat must be meas
re to1 of1,r 1afn ,a1
physical character made out. Much of
this work has been done, yet vastly more
remains to be accomplished. Let us
look at some of the results thus far
obtained, and glance at few problems
which the future has yet to solve. We
will confine ourselves the one subject of
the solar heat.
Three great cardinal questions at once
arise before us What is the tempera-
ture of the sun? How much heat does it
emit in given time And from what
source is its energy derived? Each of
these problems involves the considera-
tion of minor ones, and is the center of
the most fascinating speculations.
The first of these questions is still far
from being settled. The data necessary
for answering it are but imperfectly un-
derstood. And yet two things may be
regarded as certain. The temperature
of the sun is unquestionably very high,
perhaps so high as to battle human con-
ception This we know from the spec
troscOpe, which reveals to us the pres
ence of metallic vapors in the solar at
mosphere. Iron, nickel, cobalt, titan
ium, and many other of our most refrac-
tory substances, substances which melt
only with extreme difficulty, are actually
boiling in the sun, and giving off vapor
as water gives off steam. That the solar
surface is intensely hot cannot be
doubted. The other point which we
may consider reasonably settled, is that
the suns temperature is different at diff
ferent points. This is indicated by the
notified surface of the fiery globe, whose
dark spots, ridges, and streaks of vary
ing brightness tell us plainly of unequal
degrees of heat. a great. amount of
evidence could be easily brought for
ward to demostrate this proposition.
The sun, then, is hot but hoW hot?
Here we are baffled. Many estimates
have been made which show astonishing
variations. One is as low as 5000 deg.
Fair. Zollner has placed the solar
temperature at 1913, 900 deg. Fahr. Eric
son, however, having loftier ideas, SAYS
4,O36,O 900 deg. Fair. and Father Secchi
will not stop short of $4,000, 900 deg.
Fair. Here is discordance on grand
scale, 1t serves, however. to illustrate
the difficulty of the problem. Quite
strangely, one of Secchi's own spec-
tostrophic observations lends strong
support to the lowest of all these puesses'
He claims that he has detected the lines
OF aqueous yapor in the spectrum of n
solar spot. But aqueous yapor is de-
composed into its elements AT temnero.
ture not very far above 5000 deg. Fahr