Perth Amboy evening news., 1922-05-24
Geographic News
Bulletins by the
National Geographic Society
About the North Pole

questions to the average man. He
has no doubt grown to look upon
the earth's belt" and its avis as
immovable lines. even though they
are imaginary. But an astronomer
in London vas quoted the other day
as asserting that the distance be-
tween, Naples, Italy and the equa-
tor has been shortened by a mile
and a half during the past 81 years,
and that Greenwich has apparently
moved half a mile tward the tropics
in less than two decades. The pos
sibility of such changes in latitude
is discussed in the following bull
letin from the Washington, ID. c.,
headquarters of the National Geo.
graphic Society:
Small Latitude Changes Recognized
There is no question that lati-
tudes change. but there is a very
large question whether the changes
are of any considerable magnitude
and whether they continue for any
great length of time in the same di-
rection. The variations that have
been established are due to a slight
wabbling OF the earth like that of
q top which is not spinning evenly
around its axis. This irregularity
does not change the direction of the
axis itself. but does change the
point of the earth's surface (the
pole-point) from which the axis
energies. By such changes most
points on the earth would have their
positions altered with reference to
the poles and to the equator. which
is always 80 degrees from the pole
point and therefore follows it in any
movement which it makes.
IF the earth's simplest possible
rotation had had a single wabble
added to it, the pole-point would
trace a closed path: that is, it would
return to the same position again
and again after the completion of
definite, equal periods. But there
are least twol distinct and unequal
wabbles known: one completed in a
year, and one in about IA months.
Their combination causes the pole--
point to wander in a rather uneven
way. tracing lines that are very
roughly eliptical and which cross
and recross each other. But these
two known wabbles cause only a
very slight variation from a steady
rotation: the 'wanderings' of the
pOlt-pOlHL DtCduSe Ol l1tIl are De-
lieved to be always within a circle
60 feet across The latitude of any
city would be changed. therefore,
because of these two recognized
wabbles of the earth. at most only
so feet north or south OF its mean
position.
May Be Steady Move South
There are other possibilities,
however, in regard to change of lat
itude. One is hat there are other
as yet unrecognized wabbles ex-
tending over longer periods which
cause the pole-point to wander in
circles or elipses that may be larger
than the so foot circle. Another
is that there may be forces in opera
ton which shift the pole-point
steadily southwark practically along
a certain line of longitude. FL
nally latitude changes might be due
to local movements, either a sliding
of relatively small sections of the
earth's crust, or to a recently post
ulated floating of the continents.
Whether there is a progressive
change of latitude has long inter-
ested astronomers. In 1900 the In
ternational Latitude Service was
formed and a string of SIX stations
was established forming a band
around the world. all within a few
feet of the parallel of north lati-
tude. 80 degrees s minutes. These
stations were situated in Japan, Rus
sian Turkestan, Sardinia, Gathers
burg. Md, Cincinnati, Ohio, and
Ukiah, Cal. Observations were made
at all the stations for II years. The
stations in Turkestan and at Gath
ersburg were closed at the end of
1924, and the international latitude
work was discontinued at the Gin
cinnati station at the end of 1915.
The remaining three stations are
continuing the observations.
Would be Little Change in Million
Years
The information assembled by
the International Latitude Service
has been interpreted in various
ways. The changes in latitude OBJ
served were very small and it is rec
ognized that the possibilities of
error due to imperfect instruments,
inaccuracies in star destinations and
the human equation, were many.
One careful analysis by the United
States Coast and Geodetic Survey,
however, seems to indicate that the
pole-point is shifting progressively
southwark toward the continent of
North America. This would mean
that in effect the cities of the United
States are moving slowly to the
north.
you need have little worry.
though. over the likelihood that
the North Pole will turn up some
day in your back yard. Even though
one becomes generous with assump-
ton and assumes hat there is a
southwark movement of the pole
point and that it will continue stead
lily, its slowness makes the assumed
shift almost negligible. The analy-
sis referred to seems to indicate
a southwark drift of the pole
amounting to a trife over six inches
a year. This would amount to less
than one mile in ten thousand years.
In one million years the change
would equal only 95 miles. At
the rate assumed. in a million years
New York city would not be shifted
as far nortt. as the latitude of Bos-
ton today. Fresno would have
reached a point only % miles north
of the present position of San Fran
cisco. and Memphis would be shift
ed to about the present position of
the south line of Kentucky"