[86] For Bruno's conjecture (in 1591), see _Jevons_, vol. ii., p. 299. For Kant's part in the nebular hypothesis, see _Lange_, _Geschichte des Materialismus_, vol. i., p. 266. For value of Plateau's beautiful experiment very cautiously estimated, see _W. Stanley Jevons_, _Principles of Science_, London, 1874, vol. ii., p. 36. Also, _Elisée Réclus_, _The Earth_, translated by Woodward, vol. i., pp. 14-18, for an estimate still more careful. For a general account of discoveries of nature of nebulæ by spectroscope, see _Draper_, _Conflict between Religion and Science_. For a careful discussion regarding the spectra of solid, liquid, and gaseous bodies, see _Schellen_, _Spectrum Analysis_, pp. 100, _et seq._ For a very thorough discussion of the bearings of discoveries made by spectrum analysis upon the nebular hypothesis, ibid., pp. 532-537. For a presentation of the difficulties yet unsolved, see article by Plummer, in London _Popular Science Review_ for January, 1875. For excellent short summary of recent observations and thought on this subject, see _T. Sterry Hunt_, _Address at the Priestley Centennial_, pp. 7, 8. For an interesting modification of this hypothesis, see Proctor's recent writings. [87] For a very careful discussion of Albert's strength in investigation and weakness in yielding to scholastic authority, see _Kopp_, _Ansichten über die Aufgabe der Chemie von Geber bis Stahl_, _Braunschweig_, 1875, pp. 64, _et seq._ For a very extended and enthusiastic biographical sketch, see _Pouchet_. For comparison of his work with that of Thomas Aquinas, see _Milman_, _History of Latin Christians_, vol. vi., 461. _Il était aussi très-habile dans les arts mécaniques, ce que le fit soupçonner d'être sorcier._ _Sprengel_, _Histoire de la Médecine_, vol. ii., p. 389. [88] For the charge of magic against scholars and others, see _Naudé_, _Apologie pour les grands hommes accusés de Magie_, _passim_. Also, _Maury_, _Hist. de la Magie_, troisième édit., pp. 214, 215. Also, _Cuvier_, _Hist. des Sciences Naturelles_, vol. i., p. 396. [89] See _Études sur Vincent de Beauvais par l'Abbé Bourgeat_, chaps. xii., xiii., xiv. Also, _Pouchet_, _Histoire des Sciences Naturelles au Moyen Age_, Paris, 1853, pp. 470, _et seq._