276 



SCIENCE 



[N. S. Vol. XXXIV. No. 870 



dynamo-electric macliines and only a short 

 paragraph (p. 495) to storage cells is very 

 unusual in this day of devotion to the prac- 

 tical. The transformer seems scarcely to be 

 mentioned. 



An unusual feature of the book is the use 

 of so-called " examples " to introduce impor- 

 tant theorems and propositions to be proved. 

 These are presented in groups at frequent in- 

 tervals and are entirely different in character 

 from the numerical examples usually given 

 in college texts. Numerical examples of the 

 ordinary sort are not wanting, but about 250 

 of them are given together at the end of the 

 book as " exercises." (It would seem better 

 to call the " exercises " examples and the " ex- 

 amples " exercises.) 



The author justifies the use of a statical 

 measure of force, the late introduction of the 

 relation of heat to energy and the use of the 

 method of rays in optics, on the ground that 

 these are in harmony with his plan of follow- 

 ing the historical order of development. 



To sound and wave-motion even less than 

 the, usual proportion of space is given, only 

 6 per cent, of the book being allowed it. 



The treatment of heat is decidedly satis- 

 factory, the use of the historical method being 

 particularly well adapted to this field. This is 

 noticeable in the discussions of thermometry 

 and of Carnot's cycle and the second law of 

 thermodynamics. The absence of tables in 

 the body of the text, characteristic of the 

 whole book, seems a marked defect in this 

 portion. There is scarcely any reference 

 made to the small group of tables given col- 

 lectively at the end of the book. 



The discussion of light is marked by a com- 

 plete separation of geometrical and physical 

 optics, each receiving practically equal at- 

 tention. The discussion of velocity of light 

 is unusually brief and that of diffraction more 

 extended than is common in college texts. 



To electricity and magnetism rather less than 

 the usual amount of space is given (24 per 

 cent, as compared with 32 per cent., the mean 

 of four recent texts). Magnetism and electro- 

 statics are treated with relative fullness, but 

 current electricity, and particularly electro- 



magnetic induction, are too briefly discussed. 

 The many teachers who desire to see in- 

 creased emphasis placed upon the historical 

 development of physical thought, will follow 

 the career of this book with special interest 

 and hope that it may have a wide introduc- 

 tion. 



A. D. Cole 



A Text-look of Physics. By H. E. Hurst 



and E. T. Lattey. New York, Van Nos- 



trand. 1910. $3.00 net. 



This new text in physics comes from two 

 Oxford University men. It is designed espe- 

 cially to fit students for the preliminary ex- 

 amination in Oxford Natural Science School. 

 In carrying out this purpose a large number 

 of examples are given, taken from actual ex- 

 aminations recently set at the universities of 

 Cambridge, Oxford and London. 



The book seems to be a combination of class 

 text and laboratory manual. Too little atten- 

 tion is given to mechanics and the properties 

 of matter are practically left out altogether. 

 Universal gravitation and harmonic motion 

 are other omitted topics. In the discussion of 

 heat no treatment of the second law of 

 thermodynamics, Carnot's cycle or the effi- 

 ciency of heat engines appears. Light is pre- 

 sented in a very elementary way and wholly 

 from the standpoint of geometrical optics. 

 Interference, diffraction and polarization are 

 not discussed at all and the treatment of 

 spectroscopy is wholly from an elementary 

 laboratory standpoint. 



An undue amount of space — 248 of the 610' 

 pages of the book — is given to electricity and 

 magnetism. (In contrast with this less than 

 100 pages are given to mechanics.) Here 

 again some curious omissions may be noted. 

 It seems particularly strange in an English 

 text to find no discussion of Crookes's tubes,, 

 cathode rays, radioactivity or electrons. 



The index is very incomplete and unsatis- 

 factory. The illustrations, print, paper and 

 general physical appearance of the book are 

 good. The treatment of many important top- 

 ics is so elementary and incomplete, and so 

 many others are omitted altogether, that the 



