The Pleasantville press. (Pleasantville, N.J.) 1912-1929, 1922-06-28

the Equator Said to Have Beer
Shortened by Mile and Half in Past
81 Years-United States Coast and
eeodetic Survey Makes Careful
Analysis of Changes in Latitude
Little Change in Million Years.
Is the latitude of this place chang
ing?
Is your home closer to the equator
or the pole than it once was?
These may appear to be foolish
questions to the average n He has
no doubt grown to look upon the
earth's belt and its axis as mmoV-
able lines, even though they are I'M
aginary. But an astronomer in Lon
don was quoted the other day as as
sorting that the distance between Ma
pies, Italy. and the equator has been
shortened by a mile and a half during
the past 81 years, and that Greenwich
has apparently moved half a mile to-
ward the tropics in less than two dec
AIDES. The possibility of such
changes in latitude is discussed in the
following bulletin from the Washing.
ton Headquarters of the National Geo.
graphic society:
'"There is no question that ATTITUDES
change, but there is a very large ques-
ton whether the changes are of any
considerable magnitude and whether
they continue for any great length of
time in the same direction. The yaria.
lions that have beer established are
due to a slight wabbling of the earth,
like that of Il top which is not spinning
evenly around its axis. This irregular
ity 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 equa'
tor, which Is always 90 degrees from
the pole-point and therefore follows it
in any movement which 1t makes.
What the Wabbles Do.
"If the earth's simplest possible ro-
tation had had a single wabble added
to 1t, 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 at least two
distinct and unequal wabbles known:
n completed in a year. and n in
about fourteen months. Their combi.
nation 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 Il
only a very slight variation from a
steady rotation the 'wanderings' of
the pole-point because of them are be-
lieved to be always within a circle go
feet across. The latitude of any city
would be changed, therefore, because
of these two recognized wabbles of the
earth, at most only 80 feet north or
south of Its mean position.
"There are other possibilities, how
ever, in regard to change of latitude.
One Is that there are other as yet I'M
recognized wabbles extending over
lOllSt DtIloiS WHICH CduSt Tie DOit-
point to wander In circles or elipses
that may be larger than the 60-foot cir
Gle.
"Whether there Is a progressive
change of ATTITUDES has long interest
ed astronomers. In 1900 the lnterna.
tional Latitude Service was formed
and a string of six stations was es-
tablished, forming a band around the
world, all within n few feet of the par
allel of north latitude, 80 degrees 8
minutes. These stations were situat.
ed in Japan, Russian Turkestan, Sar-
DINA, Gaithersburg, Md, Cincinnati,
o., and Ukiah, Cal. Observations were
made at all the stations for IA years.
The stations in Turkestan and at
Gaithersburg were closed at the end
of 1914, and the international latitude
work was discontinued at the Cincin.
natl station at the end Of 1915. The
remaining three stations are continu.
ing the observations.
Little Change In Million Years.
1.-THE information assembled by the
lhtei hutloudi LdlIluut ofIFlCt HAS
been interpreted in various ways. The
changes in ATTITUDES observed were
very small and it Is recognized that
the possibilities of error due to i'm.
perfect instruments, inaccuracies in
star declarations, and the human equa.
ton, were many. One careful analysis
by the United States coast and geo
detic survey, however, seems to indi-
cate 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 slow
ly TO the north,
"You need have little worry, though,
oven the likelihood that the North Pole
will turn up some day in your back
yard. Even though one becomes gem
erous with assumptions and assumes
that there is a southwark movement
of the pole-point and that 1t will CON
tinue steadily, its slowness makes the
assumed shift almost negligible. The
analysis referred to seems to Indicate
a southwark drift Of the pole amount
ing to a trife over six inches a year.
This would amount to less than one
mile In 10000 years. In 100000 years
the change would equal only 95 miles.
pareonaI Details.