The Washington herald., 1909-03-07
EARTH SHAKES DAILY
Conforms with Tidal Motion
Twice Every a Hours.
LATEST WRINKLE IN SCIENCE
Special Instruments show that Globe
Rises and Falls About Eight
Inche--LOndOn Scientists Take Up
Tides as Fad-Recent "COnhrma-
tiOn" OF Fact Was Not Needed.

ffom the CHIEF European Correspondent Of the
Latfan News Bureau
London. May Camille Flammarion
caused sensation in Paris the other
day by making what he described as
the almost incredible announcement
that IL had been established as the
result of recent observations that the
earth twice every day experiences gen
eral undulations corresponding to the
tides Of the ocean. This discovery is
due TO the observations made at the
Potsdam Observatory by the astrono-
mer Hecker, who by means OF special
instruments has ascertaineG that the
apparently solid earth is sloject 10
daily oscillations analogous to the
tides. rising and falling twice in every
twenty-four hours some 20 centimeters,
or about eight inches The movements
are not noticeable any more than is the
action Of the tides TO any one on board
a ship at sea.
Interest In the announcement quickly
spread TO London, and earth tides
sprang into sudden fame as the latest
new thing in science. AS a matter OF
fact, there was no reason form. Flam-
marion TO describe his announcement
Of Prof Hecker's observations as al
most Incredible" The fact that the
attraction OF the moon. which causes
obvious periodic movements in the
liquid oceans. must also produce a sim
liar effect on the solid crust OF the
earth has been recognized by physicists
and astronomers for many years.
Series of Tests
More than twenty-five years ago.
Sir George Darwin and his brother,
Horace Darwin. sons OF the great
Charles Darwin. together made an
elaborate series Of experiments with a
view TO computing the yield Of the
earth to tidal forces. They concluded
that almost all the movements OF their
very delicate pendulum which they
could measure were due to extraneous
causes. such as minute earthquakes and
effects of temperature and pressure.
Sir George Darwin referred to thess
experiments OF himself and his brother
IN an address cOuched in popular Ian.
Guage given at the Authors Club last
Monday night. His subject was the IN
fluence Of tides on man When ne dealt
with the matter OF earth tides. and his
remarks must have been prepared before
NJ Flammarion's almost Incredible an
nOuncement had been made. he said:
IF the earth we're made OF steel Il
would be easy for the mathematician tC
calculate how much II would rise and
fall with the tide. In fact, II would move
up and down One-third as much as II q
were liquid throughout. but we should bs
quite unconscious Of this movement, be
case We have nothing by which TO meas
ure it,
But these undetectable vertical move
ments must be accompanied by excessive
! ly minute oscillations OF a plumb line
No one could measure these oscillation,
by means or a lump OF lead tied to Z
string; but indirect methods have beer
devised which lead 10 the same result
My brother and 7 made the attempt some
twenty-five years ago. but failed for Tea-
sons into which cannot go.
DR.. Hecker Succeeds.
Others since then have made more OF
less successful attempts, and at Length
DR.. Hecker. al Potsdam. has succeeded
fully. His apparatus Is In chamber cu1
below the earth's surface. and he has
continued 70 obtain observations by
means Of photography day and night foi
six years.
1T is from there observations that It 1:
possible to determine how stiT the eartl
is, and we find 1t to be just about as stiff
as If II were made OF steel throughout
The amount OF. vertical rise and fan car
be inferred roughly from DR.. Hecker'I
observations. I dare say II may be in our
latitude about four inches or five inches
so We could easily perceive 1t II there was
any fixed point by which 10 measure the
movement"
Although Sir George Darwin credits DR.
Hecker with full success in measuring
the earth tide. and his authority is great
there is still an inclination among ner
Of science to wait until HeckeT's figures
have been thoroughly examined before
accepting them completely. Many ex.
perimenters have attempted the problem
and though they have often claimed sue.
cess, they have produced little evidence
In support of their statements.