Ypsilanti sentinel. [volume] (Ypsilanti, Washtenaw Co., Mich.) 1843-1900, 1845-05-28
Physical Constitution of the sam.


sitions have been proposed to explain them. One
supp"ses them to be scori@, or dark scales of in
combustible matter, floating on the general surface
Of The sun. ThsSbh snpposes them 10 be ex.
csvations in the luminous matter which coats the
sun, The Dark part "fthe spot being a part of the
solid non luminous nucleus Of the sun. In this
latter supsosKon i, is assam ID that the physical
cunst tuiIoL oil Inc is I'D no luminous
globe. covered with coating of certain thick.
ness e luminous matter. This last suppcsition
has been great measure demonstrated by COZ
tunued III accurdl t eb crvatons oa The SPOTS.
That they excavations, and not mere patch
rs'on the surface is fully proved by the lAlow-
ing observ ,tious. Ii we ss9ect spot at. or near
the centre %. the su,'s disc, having some definite
form, circle for Instance, aud walci The appear
ance Of the same spot when by The umlIon Of the
sun on its axis, tts carried towards the dye, we
find hrsr, that the CT Gle becomes oval. This
howevr Is wha, would be expected even il the spot
were u circular patch, inastnuch as a circle scen
obquely IS fufeshjrieaed lido oval. Bat We
find that the spu, moyes tow ards the SIDE OF the
suns limb, The black patch gradually disappears.
the penunbral iiiege on the inside of The spot be-
comes invisible, while The pesumbral finge Gu the
ou side of the spo, increases IN apparent BREADTH
30 that whei the spot approaches the edge OF the
sun; the only part that visible is the external
penumbral fringe. Now this is exactly what
would occur IT the spot were an excavation. The
penum0fal fringe is produced by the shelving OF
the sides of The excavation, sloping down 10 lis
dark basis. As the spot is carried toward the
edge Of The sun, the height of The inner SIDE Is IN
terposed between the eye aud the bottom of the ex
cavalion, 50 as To conceal the latter from view
The surface of the liner side also takes very near
w the direction of the liue of vision. diminIshes 10
apparent breadth, and ceases to be visible, while
the surface of the shelving side next the edge OF
the sun becomes nearly perpendicular 10 the line
of vision, AID consequently appears OF lis full
breadth.
In short, all the variations OF appearance which
the spots undergo, as they move across the suns
d,sc, changing their distances and positions with re-
gard to the SUMS centre, are exactly those cha n
ges Of appearance which would be produced by
an excavation, and not at all those which dark
patch on the solar surface would undergo.
1t may be considered then as proved. that the
spots on the sun are excaya ions; and that the ap
parent b.ackness is produced by the fact that the
part constituting the dark portion ofhe spot, is Ell.
Their surface totally destitute of light, or by COM
parison so much less luminous than the general
surface of the sun as to spPear black.
numbral edges of the spots have led to the sappo.
sition, which appears scarcely TO admit of doubt,
that the solid, opaque nucleus, or globe Of the sun,
is invested with two atmospheres, tina; nearest i,
being like our own, non luminous. and the superb
or one being that from which light and heat are
evolved; at all events, whether these strata be in
the gaseous state or not the existence of two such,
one placed above the other, the superior being lu-
mnous, seems to be exempt from doubt.
By observing the magnitude OF the spots. and
the rate at which they increase and diminish, the
velocity of their edges has been ascerlained, end
this velocity is such can scarcely be attributed
TO matter except in the gaseous form.
We are not warranted in assuming that the
black portion ofthe spots are really surfaces des-
tue of light, for the most intense artificial light
which can be produced, such for example, as that
of "a piece Of quick lime exposed to the action of
the compound blow. pipe, when placed between
the eve and the sun, appears as dark as the spots
themselves; an effect which must be ascribed to
the infinitely superior splendor Of the suns light.
All that can be legtmatly inferred respecting the
spots them is, not that they are destitute of light,
but that they are incomparably less brilliant than
the general surface of tho sun.
TIE thickness ofthe luminous coating which
covers The sun, was attempted to be measured by
Sir William Herschell, by means of observations
on the spots, and the result ofhis inquiry wasthal
its depth varied from two TO three thousand miles.
The under. non luminous stratum, by rejecting
a considerable portion ofihe rays which fall upon
il from the luminous stratum above. not only IN
creases the light which the luminous stratum dis
perses through space, bnt serves the purpose of a
canopy to screen the solid body of the from the
overpowering effects of the light and heat of the
Superior stratum. Hersehel even supposed that
the density of:he lower stratum might be such as
to maintain temperature on the actual scriace
the solid globe of the sun not higher than thai
upon our earth. However this may be, there is
little doubt that the actual temperature at the Wis.,
ibIe surface of The SUI, that is to say. upon its u
minous coating, must be much more elevated thar
any artificial heat we are able to produce.
Lardner's Lectures.
Il say, Jim, they tell me there is man dowr
east that is so industrious that he works 25 hours
aday."
How is that Cuay! There is only "a in
day."
w by, he gets up an hour before daylight yo'
supd niger