Geology and Mineralogy. 481 



present volume constitutes a revision of "The Elements of Elec- 

 tricity and Magnetism" by the same authors and publishers (1908). 



The text is broadly divided into three Parts, the chapters in 

 the first of these dealing successively with the elementary theory 

 of ferro-magnetism and of electro-magnetism, with induced elec- 

 tromotive force and inductance, with the magnetic properties of 

 iron, and with ship's magnetism and the compensation of the com- 

 pass. The topics discussed in Part II are, respectively, electric 

 charge and the condenser, theory of the electric field, theory of 

 potential and electric oscillations and electric waves. Part III is 

 coextensive with chapter X, which is entitled "The Electron 

 Theory." 138 problems (with answers) are appended to the 

 several chapters. 



The present volume possesses the same desirable features as 

 characterize the earlier text-books by W. S. Franklin and his col- 

 leagues (see vol. xxxix, page 314). On the other hand, one error, 

 which has been carried over from the 1913 edition of " The Ele- 

 ments of Electricity and Magnetism," should no longer pass unno- 

 ticed. On pages 277, 290, and 296 the ratio of the mass of an 

 electron to the mass of a hydrogen atom is given as " 1 / 800 " 

 instead of 1 / 1830, approximately. h. s. u. 



II. Geology and Mineralogy. 



1. Canada, Department of Mines, (1) Geological Survey 

 Branch ; R. W. Brock, Director: Among the recent publica- 

 tions of the Canadian Geological Survey may be mentioned the 

 following : 



Summary Report for the calendar year 1913. Pp. 417 ; 9 

 maps. The Twelfth International Congress met at Toronto in 

 August, 1913, and with its numerous extended excursions, 

 absorbed the time of many of the geologists of the Survey, but 

 considerable important work was also done in the field. Some 

 thirty-three individuals and parties are mentioned as having been 

 engaged in investigations in different parts of the Dominion. In 

 addition much was accomplished in the topographical, anthropo- 

 logical and other divisions. 



Memoirs.— No. 20-E. Gold Fields of Nova Scotia; by W. 

 Malcolm. Compiled largely from the results of investigations 

 by E. R. Faribault. Pp. 331 ; 42 pis., 24 figs., 2 maps. 



No. 38, Geology of the North American Cordillera at the 

 Forty-ninth Parallel ; by Reginald A. Daly. In three parts. 

 Pp. 1-546, 547-857; with numerous figures, tables, also maps in 

 pocket (Part III.). This important contribution to North Amer- 

 ican geology will be noticed in a later number. 



No. 41, The "Fern Ledges": Carboniferous Flora of St. 

 John, N. B.; by Marie C. Stopes. Pp. 142 ; 25 pis. Noticed 

 on p. 219 of the February number. 



