Reviews and Book Notices 



An Introduction to Astronomy. By Forest Ray Moulton. Lon- 

 don-New York: The Macmillan Co., 1906. Pp. 557. 



As geology is the domestic chapter of astronomy, the broad-minded 

 geologist cannot be indifferent to the appearance of a synoptical treatise 

 which brings within easy reach the essential advances in this old but ever 

 new and fascinating science. Dr. Moulton's book is eminently opportune and 

 welcome, since it covers in clear and firm terms those phases of astronomy 

 which are just now most serviceable to the student of the genesis of the 

 earth. In the first fourteen chapters the book sets forth the methods by 

 which the science is developed, the important features of the solar system, 

 and the mechanical principles involved in celestial dynamics. The selec- 

 tion of the matter is notable in that the most fundamental and essential 

 facts are chosen, rather than those that are of most spectacular and super- 

 ficial attractiveness. Perhaps in no other book of its kind is there so 

 large a proportion of the things that it is essential for one to know, if one is 

 to follow the progress of astronomical geology, as in this treatise, modestly 

 styled an introduction to astronomy. And as these come from the hand 

 of a specialist in celestial mechanics, they may be accepted with unusual 

 confidence. A notable feature of the treatment is the close tying of facts 

 to principles, by virtue of which the facts teach the principles, and the 

 principles give the facts coherence, and meaning, and help one to hold them. 



On the firm grounding of facts set forth in the first fourteen chapters, 

 the evolution of the solar system is discussed with a fulness and precision 

 found in no other astronomical work of its grade. The views of Thomas 

 Wright and Kant are briefly noticed, while those of Laplace, Lockyer and 

 George Darwin are more fully treated. The facts that support the Laplacian 

 view and its modifications are cited and set over against the facts incon- 

 sistent with it, especially those that have been developed by recent studies 

 and discoveries. The planetesimal or spiral-nebular hypothesis is as fully 

 set forth as the hmits of such a work permit, and, naturally, as coming 

 from one who has taken an essential part in its development, in an appre- 

 ciative and sympathetic way. Dr. Moulton's treatment is in many respects 

 different from that of Chamberlin, though completely in harmony with it, 

 and to those to whom the mathematical form of treatment is helpful it 

 will doubtless be found more acceptable. It may, however, be easily fol- 



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