The morning news. [volume] (Savannah, Ga.) 1887-1900, 1900-02-11

total development within the nineteenth
century. though it is true That the scien-
tlfic gains of the century do not include
such splendid achievements as the Newton
theory of gravitation, the Copernican ac-
count of the solar system, or the primary
concepts of the atomic hypothesis. The
rate of advance in scientific knowledge
has been more uniform also in the last
hundred years than in the earlier CEN
turtles The discoveries in each field have
served as never before to help on inquiries
in adjacent fields, with the result that
the explorers have moved forward in toucl
with one another. Nearly every branch
of science has helped and been helped by
the others. To this interaction of learn
ing-a marked feature of our age-we may
in large measure attribute the surprising
advance it has won. To it we clearly owe
the singularly rapid gain which has been
made in all that relates to tihe explanation
of the earth. Geological science is not a
distinct branch of learning, as is chemis-
try or astronomy 1t is a body of varied
knowledge, drawn from the stores of ell
the others and so combined as to render
an account of what has gone on in and
upon this sphere.
The conditions under which the group Of
sciences termed geology has developed
have set important limits of its sue
cesSes A hundred years ago the pioneers
had Just fairly begun to interpret the tan
gle of rocks which make up the so-called
crust of the earth and to speculate as
TO the meaning of the evidence concern
ing the condition of its interior. From
the point of view of scientific inquiry
these speculations had advanced but lit
tie beyond the position to which they had
been brought by electricity century be-
fore. The real advance in the science
was attained in the main by close study
of the structure and attitude of the rocks,
together with the organic remains which
those laid down in water so often con-
tain. In this way the division of the past
history of the earth into ages, epochs or
periods, a task begun in earlier times,
has been carried so far that we now have
a fairly clear idea as TO the way in which
the record is divided into chapters and
sections, and a general, though still very
incomplete, knowledge of the order of
events on those parts of the crust which
have been lifted above the level of the sea.
This store Of facts enables us fairly 10
interpret so much of the history of the
earth as is written in stratifed rocks that
have at no time in their history been bu-
ried to greater depth than from twenty
to thirty miles below the surface.
Deepest Depths Hard to study.
While the facts revealed in the newer
stratified rocks-those which commonly lie
in a little changed form near the surface
ARE easy to be interpreted. there are diff
culties in this work which increase in
rapid measure as they concern beds that
have been deeply buried. The reason for
this is that. in proportion as the strata are
covered nv others subsequently, laid down
they are brought into a region where they
are subjected to a number of physical and
chemical actions, concerning which we
can know nothing by direct observation
we can not submit this sphere to dissec-
ton. The deepest mining work penetrates
only about one four thousandth OF the
way to the centre. So far as we can as
certain, the oldest and for time deepest
buried rocks have not been more than one
or two score miles below the sea level
The first and in some ways the most inn
portant point that our century has made
as TO the depths of this sphere consists in
determination of the heat of its interior
and the origin thereof. The evidence of
a high temperature in the depths of the
earth, afford d by hot springs and volca-
noes is so clear that the Greeks appear to
have noted its meaning and to have con-
iectured the existence of some kind of
central fire, burning after the manner of
a furnace. This view indeed appears TO
have been commonly held by all the early
geologic inquirers who considered the
facts. So, too, it has long been known that
there was in some mines a distinct in
crease in heat to be noted in any consider
ably descent. The main gain in this in
curry has consisted of a determination as
TO the rate of increase and the source of
this high temperature which exists in the
depths. Many careful observations, dis
tributed over all the continents, show us
for nj defiance have i'll
etrated with shafts and borings, the in
crease is at an average rate of one degree
Fahrenheit approximately for each fifty
feet of depth. At this rate the tempera-
ture at the center would attain TO about
100000 degrees.
The Earth Not Fluid Inside.
But there are various reasons why this
intense heat can not really exist. How
then. can we account for the error? II
may be explained by what We may OBJ
serve or compute as taking place in any
cooler body. II is a perfectly warrantable
supposition that the earth, at a remote
period, was in a state of igneous fiuidity;
that the mass was dong kept at about
the same temperature by a process or
boiling. When the sphere assumed It's
present state of approximate solidity its
further cooling would have led to the chill
ing of the outer part, while the central
portion remained az near its original heat.
these conditions, We should have rapid
increase of temperature for perhaps few
score miles downward; while below a GER
tain level the increase of heat would be az
a steadily diminished rate-the greater
part of the internal mass being az a rather
uniform heat.
When the understanding of the evil
dence derived from volcanoes had ad-
venced beyond the primitive notion that
they were due to some kind of subter-
ransan combustion, such as takes place
in burning coal beds, biologists adopted
the view that they proved the interior to
be in fluid state, substantially like mott
en- glass or iron. 1t did not seem possible
otherwise to account for the outpourng
of lavas ia such quantities that they have
covered TO great depths areas many thous-
and square miles in extent
Further proof 10 the same effect SEEM
ed 10 be afforded by the fact that wherever
we have access TO crystalline rocks such
as granite which have been brought into