NEW BOOKS COUDERC.Encyclopedie Gauthiers Villars, 1932. Dans le champs solaire. BY PAUL Written as a companion to the author’s Architecture de I’Uniuers, the present volume deals, as the title expresses, with the solar system-a rather ungrateful, banal subject, in the author’s opinion, when compared with the newer and wider vistas opened in stellar astronomy. I n order to preserve the sense of unity with the previous volume, this one has been written with the guiding principle that the methods as well as the results of astrophysics should be accorded the principal emphasis, while furthermore the relationship between the sun and its planetary system and the stellar universe at large should be clearly realized. It is natural, therefore, to find that the book differs considerably frommost treatises on the same subject, and i t is emphatically not a textbook. Some of these deviations render the book only more attractive-at least in the reviewer’s opinion, such as the historical introduction, and the rather detailed exposition of the various theories for the origin of the system. Some other features would seem to have just the opposite effect, as, e.g., the unduly emphasized description of the earth and its atmosphere, and the very brief, almost hasty, r6sum6 of the planets and their satellites which are accorded barely as much space as the subsequent description of the nearest stars, the motion of the sun among and with these, and that of the structure and motion of the galaxy as a whole-all of which would seem rather irrelevant in connection with the planetary system. More than one-third of the book is devoted to the sun, while comets and meteors, treated almost as an afterthought, coming after the description of the solar neighborhood, have no more than eleven pages allotted t o them. Probably all this is due to the desire already referred to, to treat the subject matter from the point of view of astrophysics, and always in relation to the stellar universe, With these limitations in view one must admit that the author has succeeded very well, for the book is clearly and interestingly written and attractively illustrated. I believe, however, that it is a fair criticism to say that i t lacks unity; the various chapters are somewhat disjointed, and give the impression more of separate articles written for different purposes. As to more specific criticisms: on page 36 one reads that i t was Bowen, who cleared up the mystery of the Aurora line, while on page 81 one obtains the impression that, among others, the Harvard and Victoria Observatories concern themselves “more or less” with solar studies. The illustrations on the sun may well be called superb; several of those portraying lunar phenomena under high magnification, are, however, distinctly mediocre. W. J. LUYTEN.
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H?/drogenIons. BY F. T. S. BRITTON. 22 x 14 cm.; pp. xvi 589. London: Chapman and Hall, 1932. Price 25 shillings (not 52 shillings as erroneously printed in the number for October, 1932). For review see volume 36, page 2687. Treatise o n Sedimentation. Second edition. BY WILLIAMH. TWENHOFEL AND COLLABORATORS. pp. 960; 121 text figures: 8 chapters. Baltimore: Williams & Wilkins, 1932. Price: $8.00. 261
