[1055] ‘Dès qu'il y a comparaison, il y a jugement.’ p. 65.
[1056] ‘La mémoire n'est donc que la sensation transformée.’ p. 17. Compare p. 61.
[1057] ‘L'imagination est la mémoire même, parvenue à toute la vivacité dont elle est susceptible.’ p. 78. ‘Or j'ai appelé imagination cette mémoire vive qui fait paroître présent ce qui est absent.’ p. 245.
[1058] ‘Il résulte de cette vérité, que la nature commence tout en nous: aussi ai-je démontré que, dans le principe ou dans le commencement, nos connoissances sont uniquement son ouvrage, que nous ne nous instruisons que d'après ses leçons, et que tout l'art de raisonner consisté à continuer comme elle nous a fait commencer.’ p. 178.
[1059] Compare Powell on Radiant Heat, p. 261, in Second Rep. of Brit. Assoc.; Whewell's History of Sciences, vol. ii. p. 526; and his Philosophy, vol. i. pp. 339, 340. Prevost was professor at Geneva; but his great views were followed up in France by Dulong and Petit; and the celebrated theory of dew by Dr. Wells is merely an application of them. Herschel's Nat. Philosophy, pp. 163, 315, 316. Respecting the further prosecution of these inquiries, and our present knowledge of radiant heat, see Liebig and Kopp's Reports, vol. i. p. 79, vol. iii. p. 30, vol. iv. p. 45.
[1060] On Fourier's mathematical theory of conduction, see Comte, Philos. Positive, vol. i. pp. 142, 175, 345, 346, 351, vol. ii. pp. 453, 551; Prout's Bridgewater Treatise, pp. 203, 204; Kelland on Heat, p. 6, in Brit. Assoc. for 1841; Erman's Siberia, vol. i. p. 243; Humboldt's Cosmos, vol. i. p. 169; Hitchcock's Geology, p. 198; Pouillet, Elémens de Physique, ii. 696, 697.
[1061] Coulomb's memoirs on electricity and magnetism were published from 1782 to 1789. Fifth Report of Brit. Assoc. p. 4. Compare Liebig and Kopp's Reports, vol. iii. p. 128; and on his relation to Œpinus, who wrote in 1759, see Whewell's Induc. Sciences, vol. iii. pp. 24–26, 35, 36, and Haüy, Traité de Minéralogie, vol. iii. p. 44, vol. iv. p. 14. There is a still fuller account of what was effected by Coulomb in M. Pouillet's able work, Elémens de Physique, vol. i. part ii. pp. 63–79, 130–135.
[1062] Fresnel belongs to the present century; but M. Biot says that the researches of Malus began before the passage of the Rhine in 1797. Biot's Life of Malus, in Biog. Univ. vol. xxvi. p. 412.
[1063] Pouillet, Elémens de Physique, vol. ii. part ii. pp. 484, 514; Report of Brit. Assoc. for 1832, p. 314; Leslie's Nat. Philos. p. 83; Whewell's Hist. of Sciences, vol. ii. pp. 408–410; Philos. of Sciences, vol. i. p. 350, vol. ii. p. 25; Herschel's Nat. Philos. p. 258.
[1064] The struggle between these rival theories, and the ease with which a man of such immense powers as Young was put down, and, as it were, suppressed, by those ignorant pretenders who presumed to criticize him, will be related in another part of this work, as a valuable illustration of the history and habits of the English mind. At present the controversy is finished, so far as the advocates of emission are concerned; but there are still difficulties on the other side, which should have prevented Dr. Whewell from expressing himself with such extreme positiveness on an unexhausted subject. This able writer says: ‘The undulatory theory of light; the only discovery which can stand by the side of the theory of universal gravitation, as a doctrine belonging to the same order, for its generality, its fertility, and its certainty.’ Whewell's Hist. of the Induc. Sciences, vol. ii. p. 425; see also p. 508.