[ 69 ] 



X. Notices respecting New Books. 

 The Principles of the Transformer. By Frederick Bedell, Jsh.D., 

 Assistant Professor of Physics in Cornell University. New York. 

 The Macmillan Co/ 1896. 



THE transformer has played so important a part in the develop- 

 ment of alternate-current systems of distributing electricity 

 that no excuse is needed for the publication of a treatise setting 

 forth the principles of its action. Such a treatise, however, unless 

 it takes into account the fact that nearly all transformers possess 

 iron cores, degenerates into little more than a mathematical dis- 

 cussion of simple harmonic functions with constant amplitudes, 

 and its practical value is thereby greatly diminished. The author 

 of the present work has, in our opinion, devoted too much space 

 to mathematics of this kind, as he only gives one short chapter on 

 the effects of hysteresis and Eoucault currents. It is somewhat 

 disappointing to read at the end of the volume that the lag due to 

 hysteresis and eddy currents may be " assumed to be 45° as an 

 approximation in a closed magnetic-circuit transformer." Surely 

 the designer of transformers will require something more definite 

 than this ! The chapters on construction and testing contain much 

 useful information, and the interesting results are described of 

 experiments upon transformers with open and closed magnetic 

 circuits, made by the method of instantaneous contact. 



The volume is well provided with figures, and especially with 

 diagrams and curves; indeed the author has made use largely of 

 the geometrical methods introduced by Blakesley and others in his 

 treatment of periodic functions. J. L. H. 



Geological Survey of Canada. Annual Report. New Series. 

 Vol. VII. Reports A, B, C, ¥, J, M, E, S, 1894. 8vo: 1206 

 pages. With 11 maps, 15 plates, and numerous figures in the 

 text. Ottaw T a : Dawson, 1896. 



Eeport "A" (pp. 1-124) is a summary of the work of the Geo- 

 logical Survey for 1894, as to explorations and surveys, and the 

 work in the Museum and Office. 



The Kamloops map-sheet to which the Eeport "B" (pages 

 1-427), by the Director, Dr. G. M. Dawson, relates covers a por- 

 tion of the Interior Plateau of British Columbia, with a compara- 

 tively small width of mountains of the adjacent Coast Eanges, on 

 its western edge, which are quite distinct from the " Coast Eanges" 

 of California and Oregon. It is a square of which the sides 

 measure eighty miles, and consequently it includes an area of 6400 

 square miles, all parts of which are in the drainage-basin of the 

 Eraser Eiver and its tributaries. The physical features are first 

 described, and, as in the other Eeports, illustrated by some good 

 plates from photographic views. The general geology follows. 



The oldest rock-formations in the Eastern District are the 



