30Novum Organum, bk. 1 Aphorism 104.31The Unity of Worlds and of Nature, 2nd edit. p. 116.32Principia, bk. iii, ad initium.33Keill, Introduction to Natural Philosophy, p. 89.34Jeremiæ Horroccii Opera Posthuma (1673), pp. 26, 27.35Young’s Works, vol. ii. p. 564.CHAPTER XXVIII. ANALOGY.1Essay on Logic, Works, vol. viii. p. 276.2Life of Faraday, by Bence Jones, vol. ii. p. 206.3Lacroix, Traité Élémentaire de Calcul Différentiel et de Calcul Intégral, 5me édit. p. 699.4Histoire des Mathématiques, vol. i. p. 298.