^{page 327 note *} Preussischen Akademie der Wissenschaften Phy.-Math. Klasse, 1928, “Neue Möglichkeit für eine einheitliche Feldtheorie,” and Ibid., 1929, “Zur einheitliche Feldtheorie.”

^{page 327 note †} Ibid., 1930, “Zwei strenge statische Lösungen der Feldgleichungen,” equations (53).

^{page 327 note ‡} Ibid., equations (50), (37), (44). As a matter of fact, in (44) μ is defined as

but, as will be shown later, the sign of m must be changed so that the metric obtained when e is zero shall represent an attractive force.

^{page 328 note *} In the General Theory of Relativity, Einstein obtained θ′u ² = k; e.g. The Mathematical Theory of Relativity, by A. S. Eddington (C.U.P.), second edition, p. 86, equation (39·41). Equation (5) reduces to this when e = 0.

^{page 329 note *} Equation (11) is the justification for changing the sign of m in the definition of μ (see note on p. 327); otherwise (11) would have represented a repulsive force.

^{page 330 note *} The Mathematical Theory of Relativity, p. 88, equation (40.6).

^{page 330 note †} Ibid., p. 91, § 41.

^{page 330 note ‡} Ibid., p. 91, § 42.