Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1900-09-06

Sea.
Every year or two the scientific
world is favored with new speculations
regarding the age of the earth by men
who are in some measure qualified to
express an opinion. Lord KeIvin's
reiterated estimate, based on the sup
posed rate Of the cooling OF the globe
from a molten mass was between TO-
100000 and 100000 years. These
figures have been received with uniyer-
sal respect, but have not been univer-
sally accepted. The biologists declare
that five or ten times as long a period
is needed to allow for the slow devel-
opment of man from the lowest fossil
forms Of life hitherto discovered. And
the biologists, after trying to form an
idea of the rate at which sedimentary
rocks are laid down today, say that
the strata already in existence could
hardly have been deposited in anything
like 100000 years. Only last year
Sir Archibald Geihie expressed dissat-
isfaction with Lord Kelvin's estimate
for this reason.
Within the last lew weeks two new
contributions to the discussion have
been made public. Prof Grove X. Gill
bert, the retiring president of the
American Association for the Advance
ment Of Science, treated one phase Of
the matter in an address on Rhythms
and Geologic Time, and Prof Jolly of
the University of Dublin has been con-
Quoting some original investigations, a
report of which has just been pub
Ished. The Washington expert VEN
tured no opinion of his own on the age
of the earth, and offered no comment
on the estimates Of others. He merely
considered the methods employed thus
far in reaching conclusions, and sug-
gested that possibly a closer study of
certain Thythms that have been OBJ
served by biologists migvt be service
able. New ways of attacking the
problem may prove more advantageous
bert recommends adhering to the latter
even while employing the former.
In many places in the earth's crust
the deposits betray a more or less
symmetrical alteration. In the coal
regions, for instance, sandstone and
shale are situated one above the other
in monotonOus succession. Else
where rocks which are of sedimentary
origin are curiously banded with
streaks of different hue. Sometimes
these markings are thin as a sheet of
paper, and sometimes they are much
thicker. But they always suggest
change of circumstances at compare
lively regular intervals. In Scandina-
via there are alternate deposits of
foreign trees and Doggy moss, which
indicate that the earths surface was
first covered with one and then the
other in a systematic manner. The re-
| cession and advance of glaciers, too,
have supeTimpOsed one stratum Of
gravel upon another, in some instances
! II successive times. A somewhat SIM
| liar qualification Of the deposits at the
mouths of big rivers leads to the sup
position that there were number of
! subsidences there, in consequence of
the weight of accumulated material.
Some influences which are supposed
to have had share in shaping the
| earth's surface are distinctly more
| periodical than others. Prof. Gilbert
! referred, for instance, to the notion
| that the retardation of the earths
rotation from tidal forces might cause
an alteration between a fiattening at
| the poles and an approach to spheric-
ity. The resulting changes of level
| would modify the condition of those
continental areas that would thus be
| exposed at one time and submerged at
another. No attempt has yet been
! made, however, to use this standard
in estimating the time represented by
adjacent geological deposits.
The phenomenon of the procession Of
! the equinoxes is completed in a period
| Of Il 900 years. At one stage of this
cycle the southern hemisphere has
| hotter summers and colder winters
| than the northern, and 10000 years
later the situation is reversed. 1t has
been suspected by Croll and others that
! local climatology would be SO altered
| by this agency as to leave some i'm
press on the geological record. Prof.
! Gilbert views that theory with some
favor, and hopes that evidence of its
soundness will be sought by biologists.
Whatever else may be thought of
Prof. Joly's recently published paper,
no lack of defniteness can be imputed
to it. The principal mineral constitu-
ent Of the sea is chloride of sodium.
Prof. Jolly thinks that all Of the So
dunn in that body of water came from
| the rocks, and was washed in there at
a comparatively uniform rate, in con-
sequence Of the action Of the weather
upon the land. The soundness of his
premises will doubtless be called in
question, but his results are interest
ing. After applying number of cor
rections to his figures, he concludes
that between 80,0OO,OOO and 100000
years have elapsed since the surface
Of the globe was first subjected to the
denuding action of rain.