[471] "Familiar Lectures on Science," p. 469.
[472] "Principles of Science," vol. ii. p. 83.
[473] Maxwell, "Theory of Heat," p. 92.
[474] Challis's "Mathematical Principles of Physics," p. 107; Herschel, "Familiar Lectures on Science," p. 467.
[475] "It is pretty much the same to the greater number even of the instructed hearers whether a man of science say 'I know' or 'I suppose;' they only ask after the result and the authority by which it is supported, not the grounds of the doubts. It is thus not to be wondered at if earnest investigators do not willingly shock the confidence of their readers in what the former may think true and demonstrable by the enumeration of ideas of the correctness of which they do not feel themselves quite secure."—Helmholtz, "On John Tyndall," in Nature, vol. x. p. 301.
[476] Jevons, "Principles of Science," vol. ii, p. 466.
[477] "Fragments of Science," p. 40.
[478] Ibid. p. 40.
[479] Marsh, "Man and Nature," chs. i. and iii.; Lyell, "Principles of Geology," pp. 713-717.
[480] Wallace, "On Natural Selection," pp. 324-326; Lyell, "Principles of Geology," pp. 681-688, 579-590.