D O C . 7 1 P R I N C E T O N L E C T U R E S 5 7 5
[110]Although the work of Charles E. St. John and other astronomers up to 1920 had cast doubt on
the existence of the “Einstein effect” in solar spectral lines, by 1920 two German astronomers,
Leonhard Ch. Grebe and Albert J. Bachem, were arguing strongly that the redshift was real (see Doc.
31, note 47). Gradually, other astronomers, including St. John, came to agree. See Hentschel 1992 and
Earman and Glymour 1980b for historical accounts of this controversy. Einstein’s statement in the
first two popular lectures that the entire theory hinged on the reality of the gravitational redshift (see
the typescript of the second popular lecture in Appendix C, pp. 19–20) attracted considerable atten-
tion in the popular press. See, for instance, the Daily Princetonian, 11 May 1921, with the headline:
“Einstein Says Theory Is Liable to Collapse.” In his summary of the second lecture, Adams said:
“Whether or not this effect exists is still a matter of controversy. And the extremely interesting remark
that Prof. Einstein made near the end was that if it is definitely proven that this effect does not exist,
then his whole general theory of relativity falls down. And his confidence in the theory is apparently
such as to lead him to believe that such an effect really will be found to exist.” New York Evening Post,
11 May 1921, p. 7. The New York Times mentioned in this context the work of St. John: “Some of his
work seems to indicate that Prof. Einstein’s conclusions are not justified by observation, but his work
has not yet reached a point where he is willing to announce a definite result.” New York Times, 11 May
1921, p. 17.
[111]The phrase “durch die Gleichung ” is not in the manuscript.
[112]In the manuscript, there is a vertical line and a question mark next to the passage “Koordina-
tensystems . . . Ablenkung.”
[113]See Earman and Glymour 1980a for a history of the eclipse expeditions, and Doc. 23 for Ein-
stein’s public announcement of the results of the 1919 expeditions.
[114]For a discussion of the method used to calculate the perihelion motion in Einstein 1915h (Vol.
6, Doc. 24), see Earman and Janssen 1993 and Vol. 4, the editorial note, “The Einstein-Besso Manu-
script on the Motion of the Perihelion of Mercury,” pp. 344–359.
[115]Schwarzschild 1916, Droste 1916a, 1916c.
[116]Weyl 1918b, sec. 30 (sec. 31 in Weyl 1922a). For earlier praise of Weyl’s method, see Einstein
to Hermann Weyl, 3 July 1918 (Vol. 8, Doc. 579). See also Doc. 19, p. [24] and note 88, and Doc. 20.
[117]In the manuscript, there are deletions in this sentence: “Im Falle eines statischen 〈räumlich zen-
tralsymmetrischen〉 Feldes muss 〈aus Symmetriegründen〉 die Form haben.”
[118]In the second German edition “ ” is corrected to “ .”
[119]The reference is to eqs. (109) and (110a), which are numbered (107) and (108a), respectively,
in the manuscript. They are corrected in the fifth English edition (Einstein 1956).
[120]In the manuscript, the expression for erroneously has “ ” instead of “ .”
[121]The manuscript has “Diese Rechnung, welche wir nicht 〈ausführen〉 darlegen wollen, ergibt für
” instead of “Die Feldgleichungen ergeben dann auf Grund dieses Ansatzes.” Weyl uses varia-
tional calculus in his derivation at this point (see note 102) in Weyl 1918b, sec. 30 (sec. 31 in Weyl
1922a).
[122]The reference here and in the previous sentence is to eq. (109a), which is numbered (109) in
the manuscript. This is corrected in the second German edition.
[123]The reference is to the unnumbered expressions for the Christoffel symbols on p. 61, which are
numbered (108b) in the manuscript and (110b) in the second German edition. The reference is cor-
rected to eq. (110b) in the second German edition.
[124]For a history of the anomalous advance of the perihelion of Mercury, see Roseveare 1982 and
Earman and Janssen 1993.
[125]In the fifth English edition (Einstein 1956), “ ” is corrected to “ .”
[126]Weyl 1918a, and Kaluza 1921. See also the correspondence with Hermann Weyl in Vol. 8 and
Einstein to Theodor Kaluza, 21 and 28 April, and 5, 14, and 29 May 1919, Ingola Kaluza, Hanover.
The need for a unified theory is already emphasized in Einstein to Rudolf Förster, 16 November 1917
(Vol. 8, Doc. 400), and in Einstein to Walter Dällenbach, after 15 June 1918 (Vol. 8, Doc. 565).
[127]In the manuscript, “unbefriedigend” replaces “〈unvollständig〉.” See Einstein 1917b (Vol. 6,
Doc. 43) for earlier views on cosmological aspects of general relativity.
[128]See Vol. 8, the editorial note, “The Einstein-De Sitter-Weyl-Klein Debate,” pp. 351–357, for
L =
ds2
z2 1 x1 2
Γ44
α
gαβ f –2
ds2
xν xμ