[477]. For even Helmholtz had sought to account for the phenomena of electrolysis by the assumption of an atomic structure of electricity.

[478]. Which in their physical aspect are individual centres of force, without parts or extension or figure. (For their metaphysical aspect, see Ency. Brit., XI edition. Article Leibniz, especially pp. 387-8.—Tr.)

[479]. M. Born, Aufbau der Materie (1920), p. 27.

(So many books and papers—strict, semi-popular and frankly popular—have been published in the last few years that references may seem superfluous, the more so as the formulation of this central theory of present-day physics. The article Matter by Rutherford in the Ency. Brit., XIIth edition (1922), and Bertrand Russell, The A.B.C. of Atoms, are perhaps the clearest elementary accounts that are possible, having regard to the scientist’s necessary reservations of judgment.—Tr.

[480]. See p. [231].

[481]. See p. [172].

[482]. See p. [121] and Vol. II, pp. 11 et seq.

[483]. See p. [169].

[484]. See p. [166] and Vol. II, p. 18.

[485]. See p. [152].