The Rock Island Argus., 1884-02-22

SldHceS tnaI 10TH us glowing orDr
Yet science has done this, and that so
perfectly that we could scarcely be more
certain even if our observers had act
uallv visited the sun and had brought
back part of his substance for examina-
ton under the microscope or in chem
ical laboratories.
cannot here fully explain how this
has been done. But may say so much
as this: The light of the sun contains
rays of all tho colors of the rainbow,
and method has been invented for sep
arating the red, orange, yellow, green.
blue, indigo and violet rays from each
other. When this is done it is found
that rays of certain tints are missing
from the light of the sun. Now, some
Of these missing tints are known to be
those which certain vapors and gases
have the power Of absorbing, as, for in
stance, the vapors of iron, zinc, cop
per and so forth, the gas hydrogen and
other substances in the vaporous or
gaseous form. We thus learn that these
substances are in the atmosphere of
the sun, much as the yapor of water and
the gases oxygen and nitrogen are
present in the atmosphere of the earth;
that is, in the air we breathe,
1t has thus been shown that hydro
gen, sodium, magnesium, calcium, iron,
aluminium, manganese, chromium. CO.
bait, nickel, zinc, copper, titanium and
other elements are present in the suns 8
atmosphere. In another way, by no.
ticing that certain tints are extra strong
in the suns light (instead of being ab-
sent or falnt) 1t has been shown that
oxygen is present (and probably also
nitrogen) in the atmosphere of the sun
as in our own.
sun SPOTS.
The spots on the sun were first dis
covered by Fabricius, Galileo and
Scheiner in the year 1910. At first the
spots were thought to be opaque bodies
travelling round the sun; but after
awhile it was seen that they move in
such way as to show that they are on
his surface. Thus it was found that
the sun turns round on his axis as the
earth does. The period in which he
thus turns on his axis is about twenty
five days, though as you will see pres
CIblNy hC IduAOb bV HulLO IOlbhlh eAS.k ~
the exact length of this period.
1t was presently discovered that the
spots appear only in certain parts Of
the suns 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 sun 5 surface which correspond in
| position with the temperate zones Of
the earth. But very singular circum-
| stance has been discovered during the
present century. The spots farthest froll
the solor equator take u longer time in
| going round than those nearest to that
| circle Judged from the tolner, the SUI
| would seem TO turn once !oant on hi:
axis in about four weeks. Judged iron
the spots nearest his equator, the time
of single rotation would seem to be
little more than three and one-hali
weeks. So that it would actually seem
as though parts of the sun near his
equator turned round eight times ir
four weeks, while in the same time the
parts of the spot zone nearest to thu
poles went round only seucn times.
APPEARANCE OF sun SPOTS.
The spots are not uniformly dark, bu
are darkest at the centre. All arount
the dark central part is what looks lik,
sort of fringe, darker than the res
of the suns surface, but not nearly 81
dark as the central region.
The spots seem to be depressions be
low the solar surface, the outer par
being the sloping sides of great saucer
shaped hollOws.
But there are not always spots on tn
sun. Sometimes for weeks in sue
cession no spots can be seen. 1t ha
been found that spots increase and de
crease in number in a somewhat regu
lar manner. From the time when ther
are none the spots gradually increas
in number and in size. Then they be
gin to get fewer and fewer in numbe
until again the sun is without spots
Then they begin to return, and so the
grow alternately more and less numel
Gus. The period in which all tn
changes are gone through, from tim
WHICH SpOlS stlC IhOSt huiLOAou9b ~ - AAAAA
when they are again most numerous,
about eleven years.
THE CAUSE OF SUN SPOTS.
The cause of this periodic change
the state of the suns surface has nc
vet been discovered. But the spot
themselves are supposed to be region
where that surface has been intensel
disturbed. Generally the parts of
surface near spot are brighter tina
the rest, forming streaks and patches {
intense brilliancy. which the al
tronomers of Galileo's time called tacu
, from Latin word signify torcl
Much smaller bright patches, mere dot
in fact, of similar brightness are strew
over the general surface of the SUI
These are called the rice-graiss.
But though they look very small, the
are in reality of enormous size-ce
tainly not less than three hundred mile
, in length and two hundred in breadth
1t is believed that nincty-niHe parts OF
of hundred of the suns light and he'
comes from these immense and II
} tensefy luminous clouds.
i When the moon comes betWeen II
earth and the sup, she somftiines 1l