Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-02-21

Africa as well as those of the American
continent, still bear its impress Was man
already in existence ? Was he witness to
this great catastrophe? To protect him
self and save his budding race did he find
some shelterirg volcano, some equatorial
Isle, a refuge forgotten in the universal cat
Rclysm?
Explanations OF the Glacial Epoch.
But the glacial epoch is inscribed in all
lts letters in the great book Of nature. Its
explanation alone remains in the region of
doubtful theory, and among the hypothesis
Imagined to explain it, that of ikening our
sun to other variable suns in the universe,
and supposing the variation in heat to have
been ff'cient to give our planet over to
the ice " hich enveloped it, is by no means
the least worthy of consideration.
Analogous events are before us in the
heavens. One OF the most remarkable ex-
Emples is that offered us by star of the
constellation of Argo, situated in the middle
OF a singular nebulosity. In 1887 this star
was of the first magnitude, ana until the
year 1854 it surpassed in brightness the
most beautiful stars in the heavens, Welding
the palm only to Sirius, which, up to 1913,
1t almost equalled. In 1856 this star began
TO wane, and, becoming inferior to all the
among those of the second. Continuing to
diminish in 1859 it stood among stars of the
third magnitude, in 1862 with those of the
fourth, in 1864 with those of the fifth, in
1857 with those OF the sixth, and in 1870 it
became
Invisible to the Naked Eye.
Beginning with the year 1871 this star
gradually passed through the various de-
grees of magnitude between the sixth and
seventh. and in 1886 attained a minimum of
S.65 Since that time it seems to be bright
ening Thus, during the time from 1856 to
1856, before our very eyes, this distant sun,
whose paralla1 is inappreciSble, whose dis
tance is formidable, whose volume is pro-
digioUs-this colossal focus of an unknown
planetary system declined through seven
degrees of brilliancy, till the time came
when onlv one-si1th of its original light
radiated from it.
What Judgment can we found on such
variations in regard to the habitability of
planetary system subjected to the irregu-
1Arities of such a sun? Should this system
contain some inhabited world like our own,
here we should have a glacial period
brought about on its surface by the gradual
waning in power of its sun. Will this sun
of Argo revive again? VIII it regain its
full power, and again shed from its increas-
ing sphere the rays of light and heat which
seemed to have departed from it forever?
We may and must believe so, and this be-
lief is in part grounded on its movements
and operations as they have been observed
during the last 200 years.
History of Variable Star.
HALEY saw this star of the fourth magni-
tude in 1917; Lacaille of the second, in
1751; Burchell, OF the fourth, in 1911; Bris-
g III r
the first, in 1921; johnson, of the second,
sn 1880; Herschel, of the first, in 1887. 1t
IS, then, sun which varies rapidly and in
wide proportions, and we may soon expect
TO see 1t pass again through all the degrees
of brightness from which it has declined.
no what cause may this enormous varia-
tion of light be due? May it be that the
'Htar removes from US with extreme rapiditv,
and that it is approaching us again when
we see its light augment? No. Because,
on the one hand, there is no movement per-
ceptible (the movement would thus require
10 take place precisely in the direction of
the visual ray which is highly improbable,
and which becomes even impossible when
we consider the large number of variable
stars that are known; and, on the other
hand, it would be necessary to admit that
the star had withdrawn, between 1856 and
1867, the whole distance required to reduce
8 star of the first magnitude to one of the
sixth, that is, to at least ten times the dis
tance of the star of first magnitude, or of
&, ,000, 900 times the radius of the earth's
prbit-which would
Suppose an E1travagant Speed,
o rate of speed which is, moreover i'm
possible to admit, inasmuch as the ray of
light which takes Is wears to reach us from
She first distance would require $50 years to
reach us from the second. The variation in
Light is not caused, therefore, by variation
IN the distance of the star.
Gould it be produced by an eclipse? 1t
would be necessary in that case to admit
that an Opaque globe as large as the star it.
telf passes directly between it and us and
masks its light for space of several years.
The very nature of the celestial movements
Is opposed to this hypothesis.
May this surprising variation in light,
then, be due to the rotation of this distant
sun op its own axis, admitting one-half of it
80 be incandescent while the other half is
covered with spots, encrusted, almost OBJ
secured. 1t is scarcely probable that star
requires at least 80 years to accomplish a
Bemi-revolution on its axis, and, moreover,
the phenomenon does not appear to offer
the regularity which would correspond with
this hypothesis.
The Only Plausible Explanation.
The most natural explanation would be to
admit that periods of superabundant bril-
iancy correspond to super-excitation in the
luminous photosphere of these distant suns.
We have seen, in studying our own sun,
that its light is dte to clouds of solid or
liquid particles burning in its comburant
atmosphere, ss carbon, calcium or msgne-