[3] Mars, by Percival Lowell, p. 207 et seq.
[4] General Astronomy, by Charles A. Young. Revised edition, 1898, p. 363.
[5] Many of the present difficulties about temperatures on the various planets would be beautifully disposed of if we could accept the theory urged by Mr. Cope Whitehouse, to the effect that the sun is not really a hot body at all, and that what we call solar light and heat are only local manifestations produced in our atmosphere by the transformation of some other form of energy transmitted from the sun; very much as the electric impulses carried by a wire from the transmitting to the receiving station on a telephone line are translated by the receiver into waves of sound. According to this theory, which is here mentioned only as an ingenuity and because something of the kind so frequently turns up in one form or another in popular semi-scientific literature, the amount of heat and light on a planet would depend mainly upon local causes.
[6] Grant's History of Physical Astronomy, p. 241.
[7] Popular Astronomy, by Simon Newcomb, p. 335.
[8] General Astronomy, by Charles A. Young. Revised edition, 1898, p. 372.
[9] "Since the discovery of Eros, the extraordinary position of its orbit has led to the suggestion that possibly Mars itself, instead of being regarded as primarily a major planet, belonging to the terrestrial group, ought rather to be considered as the greatest of the asteroids, and a part of the original body from which the asteroidal system was formed."—J. Bauschinger, Astronomische Nachrichten, No. 3542.
[10] The Observatory, No. 286, December, 1899.
[11] Davy, of course, was aware that, owing to increase of distance, the sun would appear to an inhabitant of Saturn with a disk only one ninetieth as great in area as that which it presents to our eyes.
[12] For further details about Saturn's rings, see The Tides, by G.H. Darwin, chap. xx.