St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1884-02-09

spots were thought to be opaque bodies
travelling round the sun; but after
awhile 1t was seen that they move i'm
such way as to show that they are on
his surface. Thus it was found that
the sun turns round on his axis rs the
earth does. The period in which he
thus turns on his axis is about twenty
five days. though as you will see pres
emily, we cannot be quite certain as to
the exact length of this period.
1t was presently discovered that the
spots appear only in certain parts of
the sun $ surface. They are never seen
near his poles, nor near that circle
midway between the poles which cor
responds with the equator of our earth.
They appear, in fact, in those zones of
the suns surface which correspond in
position with the temperate zones of
the earth. But a very singular circum-
stance has been discovered during the
present century. The spots farthest from
the solor equator take a longer time in
going round than those nearest to that
circle. Judged from the former. the sun
would seem to turn once round on his
axis in about four weeks. Judged from
the spots nearest his equator, the time
of single rotation would seem to be
little more than three and one-half
weeks. So that it would actually seem
as though parts of the sun near his
equator turned round eight times in
four weeks, while in the same time the
parts of the spot zone nearest to tho
poles went round only seren times.
APPEARANCE OF Sun SPOTS.
The spots are not uniformly dark. but
are darkest at the centre. All around
the dark central part is what looks like
sort of fringe, darker than the rest
of the suns surface, but not nearly so
dark as the central region.
The spots seem to be depressions be-
low the solar surface, the outer part
being the sloping sides of great saucer
shaped hollows.
But there are not always spots on the
sun. Sometimes for weeks in sue
cession no spots can be seen. 1t has
been found that spots increase and de-
crease in number in a somewhat regu-
lar manner. From the time when there
are none the spots gradually increase
in number and in size. Then they be-
gin TO get fewer and fewer in number
until again the sun is without spots.
Then they begin to return, and so they
grow alternately more and less numer-
Gus. The period in which all the
changes are gone through. from time
when spots are most numerous to time
when they are again most numerous, is
about eleven years.
THE CAUSE OF sun SPOTS.
The cause of this periodic change in
the state of the suns surface has not
yet been discovered. But the spots
are supposed to be regions
where that surface has been intensely
disturbed. Generally the parts of
surface near spot are brighter than
the rest, forming streaks and patches of
intense brilliancy, which the as
tronomers of Galileo's time called Jacul,
from Latin word signify torch.
Much smaller bright patches. mere dots
in fact, of similar brightness are strewn
over the general surface of the sun.
These are called the rice-grdins.
But though they look very small, they
,re in reality of enormous size-cer-
ainly not less than three hundred miles
IN length and two hundred in breadth.
1t is believed that nincty-nine parts ont
IF hundred of the suns light and heat
comes from these immense and in
ensely luminous clouds.
When the moon comes between the
Earth and the sun, she sometimes lust
hides the sun from view. and then we
,an see all around the dark body of the
,clipsing moon ruddy objects looking
ike rosy mountains. clouds and flames.
They were compared by those who first
discovered them to garnets round a
,rooch of jet. These in reality belong
o the sun, and are vast masses of glow
no gas, reaching twenty, thirty. forty,
lay, sometimes even eighty thousand
niles above his surface Outside these
gain there can be seen during an eclipse
! glory of light around the dark body
# the moon, called the corona. This
'elongs to the sun, and is probably
aused by tiny bodies travelling in inn
nense numbers Qike clouds of dusD
round the sun and illuminated by his
ight.-Richdrd Il. Proctor, in Youths