Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-09-28

h Cleveland, md collaborating with Prof T. w.
Morley.
Eliminating the allowance made far nm
avoidable error, no drift was found. Thas fact
established, physicists the world over set them
selves to explaining why, and Profs. H. A.
Torrents Of Holland and G. r. Fitzgerald Of
Ireland worked out a solution, now best known
as the Fitzgerald contraction, and one Of the
statements Of science which laymen have found
it most dificulit to understand. The Fitzgerald
contraction asserts that motion through space
produces an actual shrinkage Of physical
objects.
EDDINGTON explains 1t this way: Suppose
that you have a rod moving at very high
speed. Let it first be pointing transverse to
its line Of motion. Now turn it through q right
angle so that it is along the line Of motion.
The rod contracts. 1t Is shorter when it Is
along the line of motion than when it is across
the line Of motion. It does not depend at all
on the material of the rod, but only on the
speed
Upon this basis Einstein advanced his pre-
hninary theory in 1905 and his general theory
in 1915 and as the world now knows, this
theory has been tested specifically on three
grounds-and proved.
However, a few years ago DR.. Dayton @.
Miller, Michelson'S successor at Case made
ether drift experiments at Mount Wilson and
announced that he had established actual
drift, indicating motion of the earth toward
the constellation of LyTa. Since astronomers
acknowledge the existence of such q motion,
the result was disconcerting to the relatfviSts.
Nicholson accepted this challenge to his own
findings, and with two assistants, Francis G.
PeaSe and Fred Pearson repeated his expert
ments of the Morley collaboration with an in
terferometer and announced the result to the
Optical Society of America on November 2.
1923, reiterating that because of the correction
of errors he found evidence more conclusive
against drift than before
THAT work." he explained to me- was done
down here in the valley. may try it again
on Mount Wilson in order to test it at q high
altitude"
In other words, though he has done the job
twice he viii try it again to eliminate every
doubt.
81 don't expect" he added dryly, "that the
result viii be different up there. But I'd Like
to try it again.
There Is another classic example of Michel
sons passion for accuracy, of which the public
has heard very little. This was the determi-
nation by him of the exact length Of the
standard meter. This measurement has been
marked with scratches a bar of platinum
iridium kept at Sevres, France, but it. like all
material substances, is subject to harm from
chemical change, theft or damage
When Nicholson went to the University of
Chicago to take charge of its department of
physics one OF his first tasks was to go to
Paris and establish the length in terms of light
the indestructihle absolute. He determined
that one meter was equal to 1,553.163.5 wave
lengths Of particular red line in the spectrum
of cadmium. So now if the bar at Sevres ever
Is lost no one need worry about the world
losing the exact knowledge of how long q
meter Is.
TT would be difficult to find out just why
Nicholson has Interested himself so COM
pletely in the phenomena of light Certainly