[85]. Brewster, p. 60.
[86]. To descend, for a moment, to details. Sir David Brewster will not allow himself to be driven to elect between the icy or watery constituency of Jupiter. He declares direct experiment to have proved that it is neither; that if Jupiter were a sphere of water, the light reflected from his surface, when in his quadratures, must contain, as it does not, a large portion of polarised light; and if his crust consist of mountains, precipices, and rocks of ice, some of whose faces must occasionally reflect the incident light at nearly the polarising angle, the polarisation of their light would be distinctly indicated. The Essayist, in his Dialogue, “doubts whether the remark is applicable; for Jupiter’s watery or icy mass must be clothed in a thick stratum of air, and aqueous vapour, and clouds. But even were the planet free from clouds, the parts of the planet’s surface from which polarised light would be reflected, would be only as points compared with the whole surface; and the common light reflected from the whole surface would quite overwhelm and obliterate the polarised light.”—Dial. p. 64. We cite this as a sample of the ingenuity of both disputants, in a point of scientific contact. Whether Sir David’s conjectural polarised light be or be not thus obliterated, in our view the item in dispute is quite lost in the general question, and the great principles on which its solution depends. If driven to elect between ice and water, asks Sir David playfully, “may we not, upon good grounds, prefer the probable ice to the possible water, and accommodate the inhabitants of Jupiter with very comfortable quarters, in huts of snow and houses of crystal, warmed by subterranean heat, and lighted with the hydrogen of its waters, and its cinders not wholly deprived of their bitumen?”—Pp. 236, 237. The answer of his opponent would be obvious.
[87]. Brewster, p. 61.
[88]. Ibid., p. 62.
[89]. Ibid., pp. 65, 66.
[90]. Ibid., pp. 68, 69.
[91]. Dial., p. 6.
[92]. Ibid., p. 23.
[93]. Dial., p. 76.
[94]. Museum, &c., vol. i. p. 35.