Cleveland morning leader. [volume] (Cleveland [Ohio]) 1854-1865, 1865-01-26
The sam GOOD for some Time Yet.

The sun Good for Some Time Yet.
Prof E. L. Youmsns, in his essays re-
Gently published, INDUCES in the following
curious speculstions:
Another essential question as regards the
future Of our planetary system has refer
ence to its future temperature and illumi-
nation. As the internal heat of the earth
has but little influence on the temperature
of the surface, the heat Of the sun is the
only thing which essentially affects the
question. The quantity Of heat falling
from the sun during given time upon q
given portion of the earth's surface may be
measured, and from this it can be calculated
how much heat in given time is seat out
from the entire sun.
Such measurements have been made by
the French physicist, Pouillet, and it has
been found that the sun gives out guam
tity of heat per hour equal to which layer
of the densest coal ten feet thick would
give out by its combustion, and hence, in 8
yesr, quantity equal to the combustion of
layer of seventeen miles. If this heat
were drawn uniformly from the entire mass
of the sun, its temperature would only be
diminished thereby one and one-third Of 8
degree centigrade per year, assuming its
capacity for heat to be equal TO that Of
water.
These results can give US an idea of the
magnitude of the emission; in relation to
the surface and mass of the sun; but they
cannot inform US whether thd sun rsdi-
ates heat as glowing body which since
its formation has its heat accumulated
within it, or q new generation of heat BY
chemical process takes place at the suns
snrfsce. At all events, the law of the con-
servation of force teaches US that no pro
cess analogous to those known at the sur
face Of the earth can supply for eternity
an inexhsustible amount of heat and light
to the sun. But the same law also teaches
that the store of force st present existing,
as heat, or what mAy become heat, is sufh-
cient for an immesuFsble time.
With regard to the store of chemical
force in the sun, we can form no conjec-
ture, and the store of heat there existing
can only be determined by very.uncertain
estimstions. If, however, we adopt the
very probable view, that the remarkable
small density of so large body is caused
! by its high temperature, and may become
| greater III tlHuej IL u4ay 10 ChiCuAbeA bHol
if the diameter of the sun were diminished
only the ten thoussndth part Of its present
length, by this act q sufficient quantity OF
heat would be generated to cover the total
emission for 2,l00 years. Such q small
change, besides, 1t would be difficult to
detect by the finest astronomical obsarvs-
tions.
Indeed from the commencement of the
period during which we possess historic
accounts that is, for period of about 1000
years, the temperature of the earth has not
sensibly diminished. From these old ages
we haye certainly no thermometric observ-
ations, but we have information regarding
the distribution Of certain cultivated plants,
the vine, the Give tree, which are very
sensitive to the changes of the mean annual
temperature, and we find that these plants
at the present moment have the same limits
of distribution that they had in thetimes Of
Abraham and Homer, from which we may
infer backwards the constsncy of the eli
mate.