The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1901-01-27
NATURE in MINIATURE
ITS FORCES REPRODUCED IN MOD
ELS AS AN OBJECT LESSON.
Apparatus mt the Harvard Geological
Laboratory to Show the Processes
of Earth Formation.

CAMBRIDGE, Mass, Jan. 26.-Nothing
ence between the old and the new school
of biologists than the very interesting
work which is being done in the Harvard
geological laboratory under the direction
of DR.. t. A. Jaggar. to show in miniature
by means of specially contrived apparatus
the great geological processes of nature.
Three-quarters of a century ago the aver
age geologist believed that the older phe-
nomena of the earth's surface-the noun
tains and valleys, the elevation of islands
and continents and the depression of the
ocean bed-were the result of tremendous
commissions such as no longer occur. To-
day he holds that they were caused by
the same steady. gradual processes that we
see in daily operation all around us. The
Harvard apparatus exemplifies these pro-
brief space of time how they work them
selves out in ages and over large areas
of land and how, always and everywhere
they are the result of the same unvarying
natural laws They are a practical confuta-
ton of old theories.
Though now used mainly for class in
struction in connection with the work in the
field it is interesting to note that much of
the apparatus was originally devised to
throw light on certain obscurities in the
laws governing geological process. The
first experiments were in ripple marks,
such as one sees on beach after the tide
has ebbed, or in fossil form in the slabs
preserved in museums, and, often, in the
common fiag-stones used for sidewalks.
Ordinarily beach structures are readily
identified with their form, but occasionally
AS when they mark the interlacing of
tiny rivulets in the sand-the fossil casts
resemble the veining of leaf so closely
that even scientists have been deceived by
their appearance, and have entered
them with formidable Latin names in the
lists of fossil plants. Ripple marks are
commonly, however, in parallel lines, unless
they have been formed around powders or
some other obstruction, when the lines be-
come radial They are not, is usually
thought, the result of the direct beat of the
waves. like the long "swash marks" So
called, which mark the successive limits of
the ebbing tide; but are caused by oscilla-
tons of the deeper water, which is in con-
slant movement from the disturbances of
and currents.
EXPERIMENT WITH SAND.
To get at the laws governing the for
nation OF these ripple marks, so far as
might be possible, tank was constructed,
six feet square and one foot deep, over
which a simple carriage was built which
could be moved to and fro at the rate and
for the distance required. Attached to this
carriage near the bottom OF the tank was
horizontal plate of glass. on which a
layer of sand was sifted, OF uniform quality
and depth in all the experiments made. The
order of nature was thus exactly reversed;
instead Of the water oscillating over the
bed of sand. the bed of sand was made to
oscillate under the water; but the principle,
of course. remained the same. Over $50
carefully lifted out after each test
and a blue print made in the sun directly
from the sand ripples. which develop with
beautiful symmetry on these plates. The
results were most interesting. especially
when compared as types with similar fossil
forms. One print shows the ripple marks
caused by two different sets Of oscillations.
the second at right angles to the first. The
effect suggests the regular arrangement
of fern leaves without the stem Leaving
out the mathematics OF the subject. the
chief law brought out was that the longer
or more frequent the oscillations, the bold
er and larger the ripple marks, measuring
from crest to crest, become. Another point
that after ripple mark had become es-
tablished. SO to speak. under uniform con-
ditions Of oscillation. the duration Of os-
citation had no further effect.
Experiments in other geological phe-
nomena have followed this study of ripple
marks. The synthesis of rocks is shown
by the actual manufacture OF such lava
as basalt, for example, by subJecting its
component chemical elements to intense
heat. and thus fusing them into SUBJ
stance which Is in all respects identical
With The natural rock. The contraction q
80 ear<h's interior, and other forcea