BrsuocRAPHY.-Camille Flammarion, La Planete Mars, etc. (2 vols., Paris, 1892-1909), a copious résumé of all publications and drawings of Mars up to 1901 ; W. H. Pickering, Mars (Boston, 1921), a collection of papers giving a brief account of the planet ; Percival Lowell, Mars and its Canals (N.Y., 1911), a summary of this author's views of the planet ; T. J. J. See, Preliminary Investigation of the Diameter of Mars, Astronomische Nachrichten, vol. 157, 97 (1901), a condensed summary of the principal measurements made between 1651 and 29oz ; R. J.
Trumpler, Observations of Mars at the opposition of 1924. Lick Obs. Bull. vol. 13, p. 19 (Berkeley, Calif. 1927), a general discussion based principally on photographs, of its surface features, diameter and other constants, including the calculation of the diameter of the solid surface from timed measurements of the markings; W. H. Wright, Photographs of Mars made with light of different colours, three papers in Publ. Astron. Soc. Pacific, vol. 36, p. 239 (San Francisco, 1924), Lick Obs. Bull., VOL 12, p. 48, 1925, and vol. 13, P. 50 (Berkeley, Calif., 1927) ; a discussion of marked variations in the appearance of Mars when photographed by light of different colours, with suggested expla nation; among subjects dealt with are the atmosphere of Mars, some of its optical properties, its extent, the phenomena of clouds and those of the polar caps; E. Pettit and S. B. Nicholson, Measurements of the Radiation of the Planet Mars; Pop. Astron. vol. 32, p. 6o1, a radiomet ric determination of the temperature of Mars; H. Struve, Uber die Lage der Marsachse and die Konstanten im Marssystem, Sitz.
Pr. Akad. Wiss. XLVIII., p. 1056 (Berlin, 191 I). The absorption spec trum of the Martian atmosphere is discussed in the following papers: P. Lowell and V. M. Slipher, Lowell Obs. Bull. No. 17 (1905) ; V. M.
Slipher, Astrophys. Journ., vol. 28, p. 397 (1908) ; F. W. Very, Lowell Obs. Bull., Nos. 36, and 41 (1909) W. W. Campbell, Astronomy and Astrophysics, vol. 13, p. 752 and in Lick Obs. Bull., vol. 5, p. 149 (19°9), vol. 6, p. II (Iwo) ; and W. S. Adams and C. S. St. John, Astrophysical Journal, vol. 63, p. 133 (1926).
The temperature of Mars, as derived from radiometric observations made at the Lowell Observatory, is discussed in papers contributed individually or jointly by W. W. Coblentz, C. 0. Lampland and D. H. Menzel to the Journ. Franklin Institute, vol. 199, p. 785 ; vol 200, p. 203 (Philadelphia, 1925) ; Sci. Papers, Bureau of Standards, Nos. 512, 553 (Washington, 1925-26) ; Astrophysical Journ. vol. 63, p. 177 (1926) ; and Publ. Astron. Soc. Pacific, vol. 39, p. 97 (1927).
Among important sources of general information may be mentioned the Monthly Notices and Memoirs of the Roy. Astronom. Soc. ; the Journal and Memoirs of the Brit. Astronom. Ass.; the Bulletin of the Soc. Astronom. de France, especially papers by E. M. Antoniadi. Popular Astronomy contains important articles by various authors, among which may be mentioned those by E. C. Slipher, and a series of reports by W. H. Pickering, beginning in vol. 22 (1914), and num bered consecutively ; the latter constitute a running comment, with numerous references, on contemporary observations of the planet. Observations made at Lowell Observatory are recorded in extenso in its Annals and Bulletins. Schiaparelli's memoirs were published prin cipally in the Memoirs of the Reale Accademia dei Lincei of Rome.