[174] Pop. Ast., vol. 12, pp. 408-9.
[175] Nature, August 29, 1889.
[176] Astrophysical Journal, vol. 26 (1907), p. 62.
[177] Bulletin, Ast. Soc. de France, January, 1904.
[178] Humboldt’s Cosmos, vol. iv. p. 532.
[179] Copernicus, vol. ii. p. 64.
[180] Knowledge, May, 1909.
[181] Journal, British Astronomical Association, January, 1909, p. 132.
[182] Ast. Nach., No. 4308.
[183] History of Physical Astronomy, p. 204.