Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1921-06-22

the ether at all. To illustrate. if an
observer were himself Immersed in
a great sphere OF rotating water and
were to send sound signals simulta
neousy forward in the direction in
which he is moving and also back
ward. and If these sound signals
were reflected by mirrors placed at
equal distances ahead and behind
him. the echoes would obviously
come back at exactly the same in
slant. provided there were no reia-
tive motion between himself and the
water. In other words. he could not
detect by such an experiment the
movement of himself or the water
unless he were moving more rapid
~ or more slowly than the water,
in which case he would be able to
detect and to measure his relative
motion with respect to the water by
the difference in the time of return
of the echo from the forward mirror
and the back mirror.
Now the results of all expert
ments of this sort UP to date in
which we have sent light signals for
ward and back have been to show
no difference in the time of return
OF the light echo to the observer.
i, From this the conclusion has been
. drawn that the ether. if it exists at
all, moves with the earth SO as to
, make it impossible &to detect any
relative motion.
The special theory of relatively
assertion that it is impossible to de
tect the motion of any body with re-
spect to the ether. The statement
would he more conservative if put
in the form that all experiments up
to the present have failed to detect
such relative motion.
Now Prof. Nicholson pointed out
some 20 years ago that if the ether
is dragged along with the earth at
its surface, it would have to be
dragged in different amount near
the equator than near the pole. be-
cause OF the fact that the motion of
rotation of the earth is greater at
the equator than at the poles. Hence
one way of testing whether or not
we can detect motion of points on
the earth's surface with respect to
the ether would be to send light
signal i'll different directions around
the earth's pole and see whether the
two signals came back to the start
ing point at the same instant If
there were any relative motion of
the earth with respect to the ether
| they would not do so. But if the
ether in the neighborhood of all por-
tions OF the earth had the same mo-
ton as the earth just beneath it. then
the two signals would come back at
exactly the same time. for the ex-
pertinent would be quite analogous
to that of an observer in the big tank
of rotating water mentioned above
The experiment was not tried in
this form because it was thought
that the form that Prof. Nicholson
did employ was practically equiva-
lent to it and showed that the re-
had been tried.
Now DR.. Silberstein has asked
Prof. Nicholson to take up again the
projected experiment because he has
computed that if the general theory
OF relatively is correct. there should
be a difference in the time of return
to the source of signals sent in op-
posite directions around the pole in
the manner indicated.
"A little computation shows that
it should be just as satisfactory to
send a beam around a circuit of
known area in the latitude of Chi
cago as in the latitude of the pole.
THE difference between this ex-
pertinent and its predecessor lies the
fact that this utilities the changing
speed which the earth's rotation i'm
poses upon points of different dis
tances from the earth's pole. while
the former was quite independent of
this fact.
prof. Nicholson has therefore
agreed in view of the immense in
terest which there is now in relativ-
ity to take up again this experiment.
which has acquired added interest
because of the fact that DR.. Silber-
STEMS analysis of the theory of rela-
tivity requires that there be a posi-
tive measurable effect when the ex-
pertinent is performed in this way.
III the predicted amount OF this
effect is exactly checked experiment