158 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1944 
III 
Let us turn our thoughts to cosmology and recall that it was during 
the first World War that Einstein’s general theory of relativity ap- 
peared. Two years later, in the war year 1917, came the first sugges- 
tion of an expanding universe. This was one interpretation of de 
Sitter’s modification of Einstein’s cosmology, implying as it did red 
shifts of the spectrum lines of faint distant objects. Incidentally, we 
may turn aside to remark that while de Sitter was then working in 
a Holland that had been allowed to remain neutral, his spirit is living 
on in the occupied and battered Holland of this war, and he, though 
dead, yet speaketh, inspiring his successors at Leiden and Amsterdam 
to carry on the tradition of astrophysical research in spite of all ex- 
ternal difficulties—thus Verweij has produced a theoretical discussion 
of Stark effect in stellar spectra which was published in Holland and 
found its way to the United States of America just before the entry 
of that country into this war. Perhaps I may add that Verweij in 
that paper dealt a hard blow at a paper by a McGill colleague and 
myself, though I do not accept it as a knock-out blow. Further re- 
search on this controversial subject is now in progress at the Dominion 
Astrophysical Observatory.? 
De Sitter had also deduced from Einstein’s theory the four con- 
clusions which offered a hope of observational confirmation. One 
of these four crucial tests was whether radiant energy passing close 
to a body with an intense gravitational field surrounding it, would be 
deflected in accordance with Newton’s law of gravitation or with Ein- 
stein’s modification of that law. It was Prof. A. S. Eddington who 
realized the great importance of making this test at the first favor- 
able opportunity, namely, at the time of the total solar eclipse which 
was to occur on May 29, 1919, with the Hyades as background. War 
or no war, all the plans and preparations were pushed ahead and thus 
it was that when the eventful day arrived, even though the Treaty of 
Versailles had not yet been signed, two British expeditions were in 
readiness to take the crucial photographs. I often reread the passage 
written by a learned mathematician and philosopher in which he 
described the meeting of the Royal Society when the results of these 
eclipse expeditions were announced, verifying as they did the theory 
of Einstein: 
The whole atmosphere of tense interest was exactly that of the Greek drama; 
we were the chorus commenting on the decree of destiny as disclosed in the 
development of a supreme incident. There was dramatic quality in the very 
staging ;—the traditional ceremonial, and in the background the picture of 
Newton to remind us that the greatest of scientific generalisations was now, after 
2? Recent work at the D. A. O. points to a confirmation of the work of Foster and Douglas 
on the interpretation of helium profiles. 
