Year: 1879

| 2bey VIII ne Numerous the Next We
Years


| Philadelphia Times.


The period is Approaching tThen the


greatest humber of spots appear on the


solar surface. Even at the present time


several are visible, and some of them OF


considerable size. A number of facts
seem to warrant the opinion of perhaps a


majority Of physicists that the changes
| on the disc of the central luminary which


the spots show to be taking place in
fiuence many phenomena on the earth.
The variations, therefore, from uniform
brightness On the great orb Of day are at
present watched with an interest which
was unknown in the infancy of optical
and astronomic science. The discovery


f the checkered physiognomy of the


lar orb is due to Calico, though &C,
counts of variations in the suns light
date as far back as the reign Of Angus
tus Caesar. In April, 1911, soon after
the invention of the telescope, spots
were observed by the Florentine astrono>
mer, and nearly at the same time by
Schreiner, German Jesuit, and Fabri-
cius, the friend Of Kepler. Being
unacquainted with any means of
diminishing the intense glare, the
first telescopists were obliged to
make their observations through
thin clouds or when the sun was near
the horizon. The blindness that embit'
tered the latter days Of Galileo WAS, no
doubt, caused by watching the sun-spots,
and the elder Herschel lost one of his
eyes in consequence of his close study of
solar phenomena. It has been found
from the examination of long series OF
observations that the times Of the great
est number of spots recur in about eleven
years. The last took place in the sum>
mer o. 1871. In that year and the pre-
ceding they were frequently observed
and measurement made of their size at
the observatory in this city, On this
occasion a spot was discovered with the
naked eye that was at.least fifty thou
sand miles in diameter. In 1859 spots of
twentysnine Thousand and even OF seys
enty-tour thousand miles are recorded.
In 1916 they were seen on several occa-
sions without the aid of the telescope.
Tue readiest way of observing the spots
is to receive the imsge of the sun either
upon screen or paper marked by per
pendicular and horizontal lines at an
equal distance from one another. Not
only the outlines of this spot, but also
its relative size can thus be very easily
traced. Many theories have been brought
forward in order to account for the spots
upon the solar surface, especially since
the rose colored flames which appear
during total eclipse of that luminary
have been shown to be caused by hydro
gen gas. But with the exception of this
TACT and the manifest effects of cyclone
like waves which rise and produce dis
turbances in portions of its disc, the
true causes OF the changes On the suns
surface, with the exception of those pro>
duced by some of the planets, as well as
the sources of its heat and light, are un~
known. Observations of the spots now
appearing, and which will become more
numerous during the next two years,
may enable physicists to determine many
questions connected with the central
luminary which are now unanswered.
The elder Herschel supposed that the
average temperature of years in which
large number of spots appears On the
solar surface is generally lower. This
has not been fnlly proved, yet the sum~
mer of 1916, SO remarkable for large
spots, was the coldest on record in the
United States.