502 Scientific Intelligence. 



Table IX, on coefficients of linear expansion, contains no explicit 

 indication of the temperature degree involved. The term bougie 

 d'ecimah is consistently written "Bourgie deciniale." Finally, 

 the number of typographical errors is quite appreciable. 



n. s. u. 

 9. General Physics. Third Edition; by Henry Cbbw. Pp. 

 xiv, 617 ; 441 figures. New York, 1916 (The Macmillan Co.). — 

 A careful comparison of the latest edition of this work with the 

 first (see vol. xxvi, page 241) shows that the text has been very 

 carefully revised. The principal changes are: (i) a more con- 

 crete and historical presentation of dynamics with greater promi- 

 nence to statics; (ii) a simpler and more unified treatment of 

 magnetism and electricity, secured by use of the electron theory; 

 (iii) a new chapter on electromagnetism, in which the entire dis- 

 cussion is based upon the two great discoveries of Oersted and 

 Faraday. The usefulness of the book is enhanced by numerous 

 minor additions such as sections on liquid air, diamagnetism, 

 atmospheric electricity, photometry, Gaede's rotary pump, the 

 Gnome gasoline engine, etc. We also note that many new refer- 

 ences to text-books have been incorporated at the ends of the 

 chapters and tbat the problems are now numbered consecutively 

 from 1 to 456. As usual, the author's style is clear and interest- 

 ing, and the text as a whole is polished and elegant. h. s. u. 



II. Geology and Mineralogy. 



1. The Coal Measures Amphibia of North America ; by 

 Roy Lee Moodie. Carnegie Institution of Washington, Publi- 

 cation No. 238, 1916, x + 222 pp., 26 pis., 43 text figs. — This 

 excellent monograph does great credit to its author and to the 

 Carnegie Institution. It brings together all that is known of 

 Paleozoic amphibians, and describes in detail 88 species in 49 

 genera found in the Coal Measures of North America. Linton, 

 Ohio, has yielded 50 species ; Mazon Creek, Illinois, 10 ; and the 

 Joggins coal field of Nova Scotia, 18. The author informs us 

 that these stegocephalians of the Coal Measures are highly differ- 

 entiated and specialized animals of aquatic, terrestrial, and 

 arboreal habitats. Specialization is seen in loss of limbs, ribs, 

 and ventral armature, and in the acquirement of claws, running 

 legs, and a long, expanded propelling tail. In size they range 

 from an inch to several feet. " No known characters of these 

 animals tend to ally them directly with any known group of 

 fislies . . . indicating a long antecedent history for the 

 amphibian group." Their origin is probably even pre-Devonian. 

 On the other hand, even the modern tailless forms seem to be 

 related to Peliort lyetti, which may have been a jumping animal. 

 Most of the forms belong to the order Microsauria, " lizard-like 

 animals with a well-developed ventral scutellation " ; they are 



