Year: 1872




tainly much higher temperature than
at present, but that was tho result OF
ternal and not of solar heat. ..t.


1t is popularity .of the SUMS heat
that as we pass upward through the at
mosphere toward the sun It's rays be.
come less and less powerful so that at
a comparatively slight elevation we
reach region ofeternal frost aud snow.
There is no heat upon the moon,
though its surface is exposed TO the
rays of the sun, as is evident from the
fact that the shining of the moon im-
parts no heat to the earth on the
contrary, so high an authority as Prof.
Tyndall considers the rays of the moon
to be cold. At the same time we are to
remember that the moon has no atmos-
phere.


Now, let US put several considera-
tions together and see what we have
No source of heat is more certain and
invariable than friction. We see the
heat-producing results Of friction every
day, on every hand. Light flashes
with velocity of $4,000 miles In a
second. What an inconcelvable degree
of rapidity! A fash of light wonld go
quite around the earth seven times in
single second. A ray of light-a quiv-
er, vibration from the sun las,les
down through the vast fields of either
and enters our atmosphere. What is
| tl,n Inta fr;n
atoms of the atmosphere and when
the ray of light has reached the earth
| ii has become heated. The sun is lu.
miaouS body ; we have no reason to be-
lieve that it Is an intensly heated
one.


| On this simple theory how easily
| these various phenomena can be under
stood. If the sun is hot body, and lf
its rays are heated when they set out
upon their Journey to the earth. the
temperature should not grow less as we
ascend through the air toward the sun
it should remain the same, to say the
least, at all accessible heights. But as
we ascend through the air the rays of
light which we encounter have met
with less resistance in their flight es.
pecially, they have not been called into
conflict with the denser stratum Of air
near the surface of the earth, and con-
sequently, they are less heated. The
absence of an atmosphere upon the
moon will account for the coldness of
that satellite for to say that hot
body will radiatc c1ld;rays is the height
of absurdity.


Just here, however, the question may
occur, why, ifheat is derived from the
friction of the sun's rays with the at
mosphere, does not the friction of the
moons rays with the same atmosphere
prodnce heat? That question is easily
answered the sun Is a self.luminous
body, the moon is not. There must be,
as there unquestionably is, very wide
constitute difference between the charac.
ter of the rays proceeding from the sun
and those proceeding from the moon
difference established by Him who,
sin the beginning made the sun,
self-luminous body, "to rule the day."
and the moon, a merely reflective body,
"to rule the night"


But it may be questioned that the
friction of the SUMS rays with the at
mosphere can be sufficient to produce
the degree of heat that we find in SUM-
beam and especially, that its flight
through few thousand additional feet
of air can cause the difference In its
temperature on the top OF the noun.
tain and at the level of the sea. We
know that the effects of friction are
wonderful. We draw match n few
inches across hard surface, and fric
| tion ignites it. A man allows q rope to
slip rapidly through his hands, and
| friction burns The fl a-h from them. A
| railroad car runs few miles without
| having its wheels properly fabricated,
and 80 much heat is evolved as to set the
car on fire. A meteor In flying through
space at a comparatively slow rate of
speed, is drawn into our atmosphere,
and causes it to take fire and burn. If
very small it is consumed in the upper
regions, and leaves only the luminous
trail of a shooting star. Ifof very large
size IL may sweep along at high ele-
walton, or plunge directly toward the
ground. Becoming highly heated i'm its
course, 1t sheds vivid light, while,
unequally expanding, it explodes,
throwing off largo fragments which
fall to the earth rs aerolites, or contin-
ue their separate course as metcors."-
When causes so comparatively trifing
are followed by effects so striking, what
may not be the result of ray Of light
flashing down through the atmosphere
at the rate of $4,000 miles in a Sec
ond


In the discoveries ofthe spectroscope,
however, there may seem to exist an
objection to our theory of the source OF


the SUMS heat. The spectroscope is 8


modern invention. Without going in


to any description of this instrument
or discussion of spectrum analysis


suffice it to say that by means Of thi
Ingenious apparatus the existence o
, iron, magnesium, sodium, hydrogen
and several other elements, in state o.
combustion in the sun, have been dis
covered. But 1t does not follow tina
there is necessarily that degree of heat


in the sun that philosophers have at
tributed to it. The luminosity Of tn
/ sun must depend upon something VIII.
t not upon the combustion of hydrogen
iron, etc? 1t Is almost certain, from


the facts already discussed, that thu
: warmth of the suns rays does not de
:. pend upon the heat of the sun, but up
, on their friction with the atoms Of tn
. atmosphere Much of the solar ligh


which illuminates the earth does no
o come directly from the sun, but is tn
Q result of the dispersion and diffusion
+ of the SUMS rays by the reflection of tn
l. atmosphere in like manner the genia
(; heat which We derive from the sun
| rays NAV he attributad Indirectly to tn