Year: 1879

The period is approaching when the
greatest number 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 change on
the disco of the central luminary which
the spots show to be taking place in
huence 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 astronomical science The discovery
of the checkered physiogomy of the solar
orb is due to Calico, though accounts of
variations in the suns light date as far
back as the reign of Augustus Caesar. In
April, 1861, soon after the invention of
the telescope, spots were observed by the
Florentine astronomer, and nearly at the
same time by Schreiner. German
Jesuit, and Fabricius, the
friend of Kepler. Being unraquainted
with any means of diminishing
the intense glare, the first tele-
9SopASeo "CAo OOA4Scu ~ Mdhc tllc1T OD-
servations through thin clouds or when
the sun was near the horizon. The blind
ness which embittered the latter DAYS of
Galileo was no doubt caused by watching
the sun spots, and the elder Herschef
lost one of his eyes in consequence of his
close stuoy of the solar phenomena.


It has been found from the examina-
ton of a long series of observations that
the time Of the greatest number of spots
recur in about eleven years. The last
took place in the summer of 1871 In
that year and the preceding they we're
frequently observed and measurements
made Of their size at the observatory in
this city. On two occasions spot was
observed with the naked eye which was
at least $4,000 miles in diameter. In
1889 spots of29, 900 and even "a, 900 miles
are recorded. In 1916 they were seen on
several occasions without the aid of the
telescope.


The readiest way to observe the spots
is to receive the image of the sun either
on screen or paper marked by perpen-
dicular, and horizontal lines at an equal
distance from each other. Not only the
outlines Of the spot, but also its relative
size can thus be easily traced. Many
theories have been brought forward to ac-
count for the spots on the solar surface,
especially since the rose-colored flames,
which appear during total eclipse of
that luminary, have been shown to be
caused by hydrogen gas. But with the
exception OF this fact and the manifest
effects of cyclone-like waves which rise
and produce disturbances in portions of
its districts, the true causes of the chang
es on the suns surface with the exception
of those produced by some of the planets,
as we'll as the sources of its heat and


light, are unknown. Observations Of the
spots now appearing, and which will be-
come more numerous during the next
two years, may enable physicists to de-
termine many questions connected with
the central luminary which are now un-
answered The older Herschel supposed
that the average temperature of years in


which large number Of spots appear on


the solar surface is generally lower. This
has not yet been fully proved, yet the
summer of 1916, so remarkably for large
spots, was the coolest on record in the


United States.