Evening star. [volume] (Washington, D.C.) 1854-1972, 1912-06-09

ance whose motive is merely general inter
est, sometimes by little man with a big tel
escope planted on some street corner, whose
interest is admittedly of pecuniary nature.
1t is to be hoped, however, that you have
yielded to the opportunities of this astron-
omer fnancier; for the sight is generally
worth much more than the small sum asked
for it. In many cases, it is true, the spots
can be seen with the naked eye through
piece of smoked glass; but they will appear
only as mere black dots on the suns surface:
while when viewed through a telescope of
even small power-protected of course with
several thicknesses of black glass-they are
seen to possess an appreciate size or
diameter, and may even show some struc-
ture.
These curious appearances on the face of
the sun must have been noted since earliest
times, although Calico is sometimes cred
tied as their discoverer with his newly in
vented telescope. They have been source
of curiosity and interest on the part of all
intelligent people, as well as the object of a
great deal of scientific research. They have
doubtless been the cause of concern too on
the part of some; for it would seem only to
be necessary for them to increase in numbers
till the whole surface of the sun should be OBJ
scured, and all life on earth would sooner or
later die out. Fortunately, there seems to be
no immediate danger of this taking place;
for the spots never cover more than an in
significant fraction of the whole surface of
the sun, and furthermore are always more or
less evanescent in character, seldom lasting
longer than few weeks or months. Some
times they appear and disappear again with
in few days. Their effect on the heat re-
ceived from the sun is very small, hardly one
part in a thousand, and any consequent eff
feet on the weather is too small to be definite
ly detected
1t has been known too for long time that
some years are more notable than Others as
regards the frequency of sunspots, and it
has been found that their frequency of oc-
currence passes through fairly well defined
maxima and minima. This sunspot period,
as it is called, is a trif1e over eleven years in
duration. Just now they are about at a
minimum of activity, and the spots in this
and neighboring years are likely to be small
as rule and of relatively infrequent occur
renee, although an occasional large spot
proves an exception to this rule. Only few
years from now, perhaps in 1915, they will
again come into prominence. The appear
ance of spots on the sun has frequently been
accompanied by marked electrical or mag
netic storms on the earth; and so marked
has this coincidence been that we are prac-
t1Callv forced to the conclusion that there is
some more or less definite connection be-
tween these two widely separated phenom-
ena.
TN spite of the great amount of scientific
study that has been expended on sunspots,
we are still far from knowing all about them;
but, thanks to the well directed efforts of
certain scientists. particularly of American
scientists, great deal has been discovered
within the last two or three years.
We have the best of reasons for believing
that the sun is an immense globe of matter,
not greatly different in composition from the
earth, perhaps, but SO highly heated as to be
in gaseous state. 1t is.some $780, 300 miles
in diameter and has mass 334, 500 times
that of the earth; with mean density of
only quarter that of the earth, however, or
IA times that of water. Various estimates
have been made of its temperature, ranging
from couple of thousand to over one million
Degrees but it is probable that its actual
temperature is in the neighborhood of ten
thousand or twelve thousand degrees Fab
renheit.
But illustrations give better idea of this
intense heat than these figures. 1t has been
computed that the sun as a whole emits heat
enough in single second to melt cylinder
of ice as long as the distance from the earth
to the sun and between two and three miles