Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1875-04-15
The Source of Solar Heat.

home and abroad, recently delivered a
| lecture on the Sources of Solar Heat"
| before the Stevens Institute of Tech
nology, at Hoboken, from which we con-
| dense as follows:
We hear so often nowadays" said the
speaker, "of the perfected achievements
of science that we may overlook the fact
that results which seem clear, when es-
| tablished, are usually reached through
! the hard lessons of wearying failure. We
SO commonly, hearing only of the final
| success, forget that there is no known rule
| to guide the search for it, that | may
| bring before you something of new inter
est if / ask you to look with me at a
problem which, though it is of the high
est Importance, science has only partly
! solved, and with many of whose diff
culties her students are still struggling.
This problem is that of the source and
probable duration of the heat of the sun
and of the degree of it's temperature"
After this brief but suggestive preface
Prof. Langley entered at once upon the
consideration of the subject to which it
refers. AS the address was essentially a
popular one, the speaker adopted such
methods Of illustration as should be
readily comprehended by the audience
The sun is globe 108 times the diane
ter Of the earth, and about 1850, 900 times
it's volume. From this globe there is
now pouring upon the earth that nearly
| 80
to sustain all life on it's surface, from
that of the date-palm in the scorching
glare of Sahara's waste to that of the
sea-weed at the bottom of the deepest
ocean cave, and yet the heat and light in
terrupted by this earth are but minute
fraction of the whole amount given forth
from the sun. With view, if possible,
to give some conceivable idea as to the
whole amount of this heat, the following
! illustration was given:
"Let US imagine that all the ice in the
world could be collected and stored upon
| a plain till it formed a pile thirty-ive
miles in diameter, and high enough to
contain the ice from the arctic and ant
arctic poles and all the supplies of the
temperate zones. Let this be supposed
to be shielded from all warmth until the
ice-product of the world thus piled there
winter after winter he'd formed a column
thirty-five miles in diameter and reach
ing out in space to the lunar orbit, so as
to form d bridge to the moon. Now let
the heat which the sun is constantly send
| ing out be turned wholly upon it, 1t is
the subject of simple proof that to first
melt it all and then boil the oceans of
water it might be melted into, and finally
to dissipate the whole in vapor, would
occupy the suns ordinary radiations not
quite one second"
| Again:
1.-THE cCal-beds of Pennsylvania would
probably supply the entire worlds con-
sumption for centuries; but ind that,
| if the source of the suns heat whatever
it Isl were withdrawn, and it were posi-
BILE to transport these coal beds there and
! burn them fast enough TO keep up the
present rate of emission and no more,
they would last considerably less than
one-thousandth part of second"
From these illustrations of the amount
Of the suns heat the lecturer advanced
to the considerations of the several theo-
ries propounded, with view to solve the
| great problem as to it's true nature and
source.
The first of these theories is that the
sun is, as it were, on fire, and that the
heat we experience is that given forth
| by conclusions of matter on it's surface.
This theory is regarded as untenable, for
the reason that, were the process one of
| simple combustion, the matter consti
tuting the sun would have been con
sumed long since, supposing that there
was present sufficient oxygen to keep up
the combustion, which is not the case.
A second and certainly curious story adj
vanced by a" an eminent natural philoso-
pher is to the effect that the heat is the
result of certain vital forces that are
still active on the suns surface, and the
action of which may be kindred to that
which produces the light of the FREELY
or the heat Of the body. Passing from
these two theories to the third, the
speaker presents what may be regarded
as certainly the only reasonable explana-
ton of the problem. The body of the
sun is in an incandescent state; that is,
it is white hot, but not in condition of
actual combustion. Assuming this,
it is possible to conceive of it's
great heat-radiating power with
out an actual exhaustion of the
matter of which it is composed. The
question then arises: Whence proceeds
the heat by which the vast mass is kept
hot? 1t is in the answer to this question
that Prof. Langley defines his views,
which indorse those originally presented
by Helmholtz. The suns heat is, &C
cording to this view, strictly {" a mode of
notion" itself renewed to finite but al
most uncomfortable extent by the shrink
ing of its mass; that is, the heat given
off BY the sun is due to the matter of
that body settling toward the center; or,
in other words, the contraction of the