New-York tribune., 1920-06-13
low DR.. Einstein Has Modified Our Ideas of Natu

calculating square root that we
need not bother with here.)
, The important point is that in this
case, where the observer and mirrors
| are moving through the ether, the
ray of light which has travelled ur
and down the direction of motion
| will take longer time for the round
trip than the ray which has Travelled
crosswise to the motion over a path
Of exactly the same length.
Could Detect Motion
We should, therefore, in this way
be able to detect motion of our own
system through the ether, and if
our measurements were sufficiently
accurate, determine it's direction and
rate.
This was attempted in the famous
Michelson-Morley experiment. The
distance of the round trip was in
this case only a few feet, and the
difference in time over the two
paths only something like a mill
lonth part of one e-billionth of a
second.
But this minute interval could be
measured by splitting ray of light
into two parts by letting part of it
be reflected sidewise from a trans
parent mirror and the rest 20
through, and reuniting the parts
after their trip.
IT one had gained on the other
by even fraction of the time of vi
bration of a single light wave the
fact could be detected, and the waves
which we ordinarily call light vi
brate at the rate of about six hun
dred' thousand billion second.
Nicholson and Morley tried their
experiment and in place of the easily
measurable result which they antici-
pated they got nothing. The light
waves came back over the two paths
IN exactly the same interval of time.
They tried it again and again at
different times Of the year, when
the earth was moving in different di-
rections around the sun, so that even
though the earth might have been
at rest IN space on some one of these
days, it certainly was not at rest on
all of them. But they always met
the same negative result.
Experiments Failed
Other optical experiments of a
more intricate nature and even
greater delicacy were attempted
with the same object of detecting the
motion of the earth through the
ether and they all failed.
After it became clear that the
trouble was not in the apparatus
or the experiment, it was evidently
necessary to account for the absence
of the predicted effect.
After various minor hypothesis
had been tried, Einstein started in
with the bold assumption that these
experiments had unveiled new law
of nature, viz, that the universe
was so constructed that it was not
possible by any physical experiment.
optical or otherwise, to detect the ex-
lstence of absolute, uniform, straight
ahead motion, or, indeed, to deter
mine whether the observers frame
OF reference was at rest or in such
uniform transitional motion.
If this is true, it follows that it is
only the relative motions of ma
terial bodies in the universe which
we can study at all.
Hence the name of the princinle
Of relativity.
A second principle following natu-
rally from the experiments which led
to the first is that the velocity Of
light in empty space will ALWAYS
come out the same, whether meas
ured by an observer moving with his
apparatus in one direction at one
rate or by one similarly moving in
another direction and at different
rate.
Novel Consequences
This principle sounds harmless
enough, but the consequences which
follow from it are so different from
our old preconceived opinions that
they often appear to US grotesque
to degree.
lake one of the simplest ones.