Evening star., 1933-12-12
LONGITUDE STUDY
MAY PROVE THEORY
Survey by Scientists May
Provide Clue to Idea Earth
Is Slipping Inside Shell.
BY the Associated Press.

BY the Associated Press.
A clue to whether old mother earth
Is ponderously slipping around inside
her thin rock crust, like a coconut IN
a loose shell, may be one result Of
worldwide survey of longitude just
completed by scientists.
The slipping, if it does take place, is
around the earth than of the earth in
side the crust. and is probably caused
by tidal forces of the sun and moon
acting on the crust, says DR.. William
Bowie of the Coast and Geodetic Survey.
The crust, hard and brittle, is only
about go miles thick. and below it lies
q mass of more plastic, highly-com-
pressed rock. The slipping would take
place approximately where the two
layers meet.
May Affect Magnetic Currents.
The survey of longitude, scientific
experiment on q worldwide scale, was
undertaken primarily to learn whether
or not the continents are drifting"
across the face of the earth, but it may
also shed light on whether there is any
basis for the slipping" idea. So far it
is purely theory, which, however, has
intrigued many scientists. Some be-
lleve that such slipping might account
for the changes in intensity of magnetic
currents which flow in the earth.
II slipping Of the crust takes place,
. says DR.. Bowie, it may cause dis
/ tortion great enough to be discovered by
: the measurements of the longitude sur
vey. In the survey. the longitude, or
distance east and west of the Greenwich
meridian, of 100 points on the earth's
surface was measured with the greatest
possible accuracy. Longitude of many
of the same points was similarly meas
ured in 1926. If their longitude has
changed since then, it may indicate the
continents have drifted. The same
changes might reveal distortions result
ing from slipping.
Process Is Very Slow.
Scientists of most of the leading ma
tions, including the United States, made
the longitude measurements during
October and November. Now the masses
of figures which they collected after
many nights of squirting through tele-
scopes at distant stars must be analyZed
and interpreted, task which will re-
quire several months.
If the continents are drifting, it is
very slow process, not enough to affect
life on earth at present. However, over
perloQ OF mllllonS OF years the con-
tinents have drifted to their present
positions after the breakup of one vast
land mass, according to the theory of
DR.. Alfred Wegener of Germany. He
discovered what he believed to be a
westward drift of Greenland amounting
to 118 feet a year.
The world longitude survey will have
more Immediately practical usefulness
than determining the drift of continents
or the slipping of the earths crust
however. 1t will serve to tie together
accurately all the longitude measure
mentS in various countries in one world
wide system, important in map-making
Many regions not included in the sur
vey in 1926 will have their exact posi-
tions on earth accurately pinned down"
by this survey.
The survey also will tie together the
time-signal services of various nations,
helping to iron out discrepancies, for
longitude is now used in measuring
time. A clock at one point can be
checked with another 5000 miles away,
because it is known how long a radio
signal takes to travel 5000 miles.