Fort Worth daily gazette. (Fort Worth, Tex.) 1882-1891, 1889-07-05

T. AIbeT- tue sun spot peflOQt ldu DScH
| pretty well made out, Professor Jevons
| tried to show that relation existed be-
| tween these spots and the commercial
crises in the markets Of the world
| Scientists have not yet been able to show
| that the spots certainly do have any eff
feet upon terrestrial meteorology, but if
| they do, it may be well that bulls and
1 bears may come and go with them too,
as crops would be influenced one way or
! the other. The truth, however, Is that
! rainfall, temperature, etc. have so far
varied without any sure relation to the
| increase or decrease of sun spots, and
astronomical physicists are as much
puzzled to make out what they do vary
with, as Wall street operator is to ac-
count for boom or a panic.
HOW TO EXAMINE THE SPOTS.
AS l said, no telescope is necessary to
show the large spot If the sky should
happen to be filled with fog or
smoke the spot may now be seen
not far from the center of the
sun g disk. Some of the best naked EVE
views of the sun are often obtained in
this manner If the fog is thick ennugh to
keep the sun from dazzling the eyes.
Such views are often possible in summer
mornings before the sun has risen high
enough to dispense the fogs. The spot is
just big enough to appear as minute
black speck near the middle of the sun
But it is very easy to get a naked eye
view of the spot with the sun in a per-
fectlv clear sky, and with very little
trouble, too. If two small panes of good
window glass are at hand, pass one of
them through the smoking flame of an
oil lamp many times, and quite rapidly,
until film of carbon is deposited. The
glass should be held up to the sun occa-
sionally to see whether the film is thick
enough to keep the sun s light from daz-
Zling the eye. Smoke the glass as evenly
as possible from one end to the other.
Then it may be used as it is, if those who
are to use it do not mind having soOty
fingers and African noses.
But If they do, paste a narrow strip of
thick paper across each end of the glass,
on the smoked side, and lay on it another
sheet of glass, unsmoked, of the same
size Then secure the two sheets to-
gether by FASTING a strip of tough, thin
paper or muslin around the edges of both
plates. Then you will have fit weapon
for attacking the sun, as clean as 1t is
inexpensive.
OF course, syp glass, an opera glass
or field glass, or telescope Of any sort,
no matter how small, is great help in
looking at the sun. But little in
strUction may be an assistance in using
it. First focus the telescope carefully on
some object mile or more distant. A
very good way is then to screw the object
glass and puff the tube full of smoke,
putting back the glass occasionally and
pointing II at the sun to see whether the
smoke is dense enough. If the glass is
not a choice one either the outer or inner
surface of it may be smoked in a lamp
flame without doing any harm, except,
perhaps, a few little scratches when the
smoky film is cleared off.
THROUGH THE TELESCOPE.
But if the telescope has stand or sup
port it can be used to the best advantage
just as it is. First focus it as before.
Then cut a hole through the middle of
sheet of cardboard one or two feet square,
large enough so that the card will fit
snugly around the brass cell which holds
the object glass. Point the telescope at
the sun, and hold a sheet of letter paper
q few inches beyond the eyegIass. The
sun may then be seen by projection upon
the paper and sharply defined image
obtained by pulling the eye piece out
little
In this way many persons can safely
look at the sun at the same time, and a
very small telescope will be big enough to
give a very good view, because the sun IS
light is so strong. The image can be
magnified as much as is desired by sim
ply removing the paper further from the
telescope, but the focus will change a
trifle each time the paper is changed. If
the projected image is eight or ten inches
in diameter, that will be large enough to
show the spots finely.
OF course the cardboard is only to keep
the direct light of the sun from falling
upon the white paper, and the darker
this paper can be kept the better the sun
can be seen. No one looking at the sun
IN this way should fail to notice how
much. brighter the disc is near the middle
than around the edges. This is a real
effect, and is due TO the sun IS own at
mosphere, which surrounds it as
spherical shell. Consequently the rays
coming from points near the edge have
traversed greater thickness of this at
mosphere than rays emanating directly
outward from the nearest point of the
sun IS surface. Thus the absorption of
the sun 5 rays is greater nearer the edge IA
and the intensity Of the light more
feeble. Accurate measures of this have
been made by some astronomers with inc
strumentS called phOtOmeters, and 1t iSsl
found that at the edge of the sua. IFS
light is about one third as intense ash1
the center. 40
This leads to an interesting consideFHr
ton relative to the total amount of solar
light absorbed by the sun s own atmos-
phere, and the most reliable estimates
show that If this atmosphere did not exist
the sun would shine about three times as
brilliantly as it does now. The color of
the sun, too, would be very different
from its present white tinged with yell
low. The solar atmosphere absorbs the
violet rays more fully than the red: SO
that If we could see the sun stripped of
its own atmosphere we should pronounce
its color blue.
WHO SAW THEM FIRST?
There is some dispute about the first
observer who ever saw sun spots, be-
cause it is now known that they are often
visible to the naked eve. Calico is
often said to have been the earliest, be-
cause he saw them with a telescope for
the first time IN 1910. Kepler assigned a
very recent date to original observation |
of spots, founding his assertions on two
verses of Virgil. In the Chinese annals !
of Father MALTA we read that in the veaS I'll