Iowa voter. [volume] (Knoxville, Iowa) 1867-1874, 1870-04-14
DR.. Gould on the Suns Heat.


THE sources of the light and heat Of the
sun-the only two Of his marvellous prep
critics apparent to the ordinary observer
are problems of the greatest difficulty.
/ wiz only say here that the most vivid
Light developed by human art, when in.
terposed between the eye and the sun, ap-
pears like q black spot upon the solar
disk. The highest temperature yet pro-
duced by man is that evolved by the COM
bustion of charcoal in OXYGEN, which Bun
and this is about fve-sevenths of the low
EFT reasonable estimate for the tempera.
4ure of the solar surface. Coal burning
at the rate Of one pound to the square
foot in about two seconds would attain
this temperature, and Rankine has esti-
mated that in the furnaces Of powerful
locomotive engines, pound of coal to
each square foot of CRATE surface is con-
sumed in from thirty to ninety seconds,
yielding heat from 10 to 1-45 IS intense
as that at the surface of the sun. az
Adopting this estimate that a heat equa
to that emitted by the sun might be at
tanned by the combustion of coal, at this
rate of one-half pound per second to the
squire foot, it is easy to find how long the
whole mass Of the sun would last, were
it composed of coal burning at that rate,
and furnished moreover with an unlimited
supply of oxygen to support the combus-
ton. Performing the calculation, we find
that the entire sun would be consumed in
little more than 1000 years, that is with
in period no longer than over which
human history extends.
And now, what is this sun of Ours-this
center round which eight large planets,
with not less than eighteen satellites and
100 small planets, are known to revolve,
beside comets unnumbered ana countless
swarms of meteors; this luminary, whose
fervent and dazzling beams radiate and
have radiated for ages with profuslOn
which has shown no signs of failing,
although the most vehement combustion
fails to equal it in heat, and the most in
tense electrical action falls short of it in
light; which, notwithstanding the enor-
rnous floods of energy which it is pouring
out, has decreased neither in weight nor
size to any extent which human skill has
sufficed to detects And does the realm OF
nature show any other object comparable
with it in magnitude or in character?
These arc among the questions which
force themselves on our consideration.
The sun is a star, apparently not unlike
che most Of those which gem the sky by
night. This seems better statement
than to say that the stars are suns,
although it would be difficult to give a
good definition for either word Our
idea of sun seems to imply that it is
center for system of planets or satellites
dependent upon it for their light and
radiant heat. There is some ground for
Believing this to be the case with some Of
the fixed stars, but for supposing it to be
80 with most of them there is no reason
other than the supposed analogy But
that the sun is star, one OF the same
great company which spangle the firma-
ment, and indeed one of the countless
myrisds which compose tbs singls nebula
which we see all around US like q
ring and call the milky way, seems well
established fact. Here, as with them,
that same law of gravitation holds unrc-
stricted sway which the double stars re-
veal to us as the guide and controller of
sheir motions. Like many of them it is
variable in its light, although only to
small extent and with long period. Like
them it is journeying through space
drawn by some powerful attraction, or
performing stupendous orbit around
some centre which astronomers have not
YET SuCCccOcu III ItCOguiA AtS OAuudi
motion has been commuted by Otto
Stray to be 150,0OO,00O miles.
And notwithstanding its awful magni-
tude, we must still regard. the sun as q
comparatively small star, at least, as not
above the average size. This is proved
by comparing his light with that of the
very few fixed stars whose distance can
be computed, and can therefore be COM
,>oraI wit IN that pf the S,1D
When we view the sun through tele
scope Of moderate power, provided with
a deep shade glass, or with solar eye
piece, we see bright disk, in which no
measurement has yet detected any varia-
ton from perfect circle. This circle is
not of equal brightness, the central portion
being much more brilliant than the parts
near the circumference. Nor is the solar
brightness equable in other respects, but
the whole surface appears notified by
small variations in brilliancy, which have
been compared to the Irregularities upon
4he rind of an orange, and to the uneven
Of. 81