The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1899-09-27
lence tending to show that the pole is

dence tending to show that the pole is
in motion.
Now we may say at once that astro-
nonnical research has not as yet re-
vealed the evidence thus expected. As
tronomy has been unable to come TO
the rescue of geological theory. From
about the year 1850, which saw the be-
ginning of the precise observation in
the modern sense, down to very recent
times astronomers were compelled to
deny the possibility of any appreciable
motion of the pole. Observational pro-
cesses,. it is true furnished slightly d.
vergent pole positions from time TO
time. Yet these discrepancies We're al
ways so minute as to be indistinSuish-
able from those slight personal errors
that are ever inseparable from results
obtainables by the fallible human eye.
But within the last few years improved
methods Of observation coupled with
extreme diligence in their application
by astronomers generally, have brought
to light a certain small motion of the
pole which had never before been DEM
onstrated in asreliable way. This mo-
ton, it IS true, is not of the character
demanded by geological theory. For
the biologists had been led to expect
motion which would be continuous in
the same direction, no matter how slow
might be its annual amount. For the
vast extent of geological time would
give even the slowest of motions an
opportunity to produce large effects,
provided its results could be continu-
ouslyS cumulative. Given time enough,
and the pole might move anywhere on
the earth, no matter how slow might
be its tortoise speed.
But the small motion we have dis
covered IS neither cumulative nor con-
tinuous in one direction. 1t is what
we call a periodic motion, the pole
swinging now to one side and now to
the other, of it's mean or average po-
sition Thus the new discovery cannot
be said to unrayel the mysterious puz-
Zle of the biologists. Yet it is not
without the keenest interest, even from
their point of view For the proof of
any form of motion in a pole previously
supposed to be absolutely at rest may
mean everything. No man can say
what results will be revealed by the
further observations now being contin-
ued with great diligence.
In the present article we propose to
consider only those motions or wob-
b1ings Of the pole that have been ascer-
tanned to be definite facts. In the first
place, it is important to explain that
any such motions as we have under
consideration will show themselves to
y
cipally in the form of changes Of ter
restrial ATTITUDES. Let us imagine a
pair of straight lines. passing through
the center of the earth and terminal
ing, one at the Observers station on
the earth's surface. and the other at
that point of the equator which is near
est to the observer. Then, according
to the. ordinary definition of latitude.
the angle between these two imainary
of observation. Now, we know, of
course: that the equator is everywhere
just ninety degrees from the pole. Con-
sequently, il the pole is subject to any
motion at all, the equator must also
partake of the motion. Thus the angle
between our two imaginary lines will
be affected directly by polar wobbling,
and the latitude obtained by astronomi-
cal observation will be subject TO quite
similar changes. To clear up the
whole question, so far as this can be.
done by the gathering Of observational
evidence it is only necessary to keep
a continuous series of latitude determi-.
nations at several observatories These.
determinations should show small var
iations similar in magnitude to the
weddings of the pole. essss II +sT &
& Let us now consider fora moment
what is meant BY the axis Of the earth.
It has long been known that this planet.
has in general the shape of a ball or
sphere. That this is 50 can be seen
at once from the way ships at sea
gradually disappear on the horizon. AS
they go farther and farther from US.
we first lose sight Of the hull. and then.
slowly and gradually the spars and
sails seem to sink down in the ocean,.
This proves that the earths surface is
curved. That it is more or less like a.
sphere is evident from the fact that it
always casts round shadow in eclip.
ses. Sometimes the earth rasses be-.
tween the sun and the eclipsed moon.
They we see the earths black shadow
projected on the moon, which would
otherwise be quite bright. This shadow
has been observed in very large num-
Der of. such eclipses, and it has always
been found to have a circular edge.
While. therefore, the earth is pretty
nearly round ball. it must not be
supposed that it is exactly spherical in
form. We may disregard the small ir-
regularities of its surface, for even the