The weekly democratic statesman. [volume] (Austin, Tex.) 1871-1883, 1883-04-12
BIRTH AND DEATH OF WORLDS.
Some of the Geological Changes That
Have Taken Place.
prof. Proctor. in Belgravia. ]


1t has been shown that had past
geological changes in the earth taken
place at the same rate as those which
are now In progress, 1OOOOO,OOO of
years at the very least would have
been required to produce those effects
which have actually been produced,
we find, since the earth's surface was
fit to be the abode of life. But re-
Gently it has been pointed out, cor
rectly, in all probability, that under
the greater tide-raising power of the
moon in past ages, these changes
would have taken place more rapidly.
As, however, certainly 100000 of
years, and probably a much longer
time, must have elapsed since the
moon was at that favorable distance
for raising tides, we are by no means
enabled, as some well-meaning but
mistaken persons have imagined, to
reduce the life-bearing stage of the
earth from duration 100000 of
years to minute fraction of such a
period. The short life, but exceeding
ly lively one, which they desire to see
established by geological or astronom-
ical reasoning, never can be demon
strated. At the very least, we must
assign 100000 years to the life-bear-
ing stage of the earth's existence. If
we now multiply this period by seven
for Jupiter we get a period of 60,O0O,-
600 years longer. But take the stage
preceding that of life on the earth.
From the researches of Bischoff into
the cooling OF MASSES of heated rock.
it seems to follow that a period of
more than 300,O0O,OO0 years must have
been required for the cooling of the
earth from temperature of 1000 cent?
grade to one of 200 degrees, a cooling
which has certainly taken place. Sup
pose, however, that these experiments,
or the calculations based ON them,
were vitiated by some error so con-
siderable as to increase the real dura-
ton of the fiery stage of our earth's
history more than ten-fold, the real
duration Of that period being only
100000 years. Multiply this in turn
by Z, and we get period of 2l0,000,-
900, or lS0OOO,OOO years longer. We
ought next to consider the vaporous
stage; but the evidence on which to
form an opinion as to the duration of
this stage of a planets history is tt o
slight to be the basis of actual calcu-
lation. Here, as Tyndall has well re-
marked, conjecture must entirely
cease" But, by considering only two
stageS-the fiery stage and the life
bearing, or rather that portion of the
life-bearing stage through which the
earth has hitherto paSsed-we find the
two monstrous time differences-1S
100000 and 100000, or 240,OO0OOO
years in all. They mean
that, if our assumption as the effect
of Jupiters superior mass is correct,
then, supposing Jupiter and the earth
to have started into existence as dis
tinct orbs at the same or nearly the
same time, 240O0O,0O0 years must
elapse before Jupiter will reach that
stage of planetary life through which
our earth is now passing. Whether
the assumption be correct or not, the
time differences between the stages of
Jupiter's life and the earth's are of
this order. They must be measured
by tens of millions if not by hundreds
of millions of years. We must note,
however, that the 240OO0,O00 years
correspond with only seventh part
of that time in the earth's history; so
that we may say that, if our assump-
lions are correct, Jupiter would now
be in the state in which our earth
was 100000 years ago, or nearer the
beginning than the end of the fiery
stage.