82 Scientific Intelligence. 



the change of resistance in manganine wire nnder pressure. The 

 nieasuroinents show that the chano-e is a linear one up to tlie limit 

 employed, that of 800k^j/cra\ Dr. Bridgeman has shown in the 

 Jefiferson Physical Laboratory that the change is linear up to 

 11,000 atmospheres. — Zeitschrift fiXr Listrumentenkunde, May, 

 1910, p. 154. " " J. T. 



8. Radiochemistry ; by A. T. Cajieron. Pp. viii, 174, with 

 3 portraits and 15 figures, London, 1910 (J. M. Dent & Sons). — 

 The author says in his preface : " The book is intended to be of 

 use to those who, having some knowledge of chemistry and 

 physics, wish to know accurately the facts and theories of the 

 subject at the present time ; it is also intended as an introduction 

 for others who wish to master the subject in its entirety." 



After having read the book through carefully the reviewer has 

 been unable to avoid the unpleasant conclusion that the author 

 has distinctly failed to attain the ideals set forth in the preceding 

 quotation. A few, typical illustrations may serve to justify this 

 adverse criticism. In the first place, the book contains many 

 errors in physics : On pages 17 and 90 the incorrect formulae 



— yl/ —')\f 



"I„/It=e " and " vj Vt — e " occur respectively. The 



former equation leads to "2 = e ," (page 18), which means 

 that a negative time is required for tlie activity to fall to half 

 value. Tlie accepted definition of the direction of an electrical 

 current is violated on page 22. On page 26 the following 

 remarkable sentence may be found : " The secondary rays, occa- 

 sionally called S-rays, also travel in straight lines, and otherwise 

 obey the light laws, but are deflected by a magnetic field." On 

 page 94 we read: "Ultraviolet light {i. e., electrons) decomposes 

 water " On the other hand, the book abounds in infelici- 

 ties of expression which may be charitably ascribed to careless 

 proof-reading. h. s. u. 



9. Ac/it Vorlesungungen ilher Theoretische PhysiJc ; von Dr. 

 Max Planck. Pp.127. Leipzig, 1910 (S. Hirzel).— These lec- 

 tures by the distinguished professor of theoretical physics in the 

 University of Berlin were given at Columbia University last year. 

 The first two lectures deal with the fundamental distinction 

 between reversible and irreversible processes, and with the appli- 

 cation of thermodynamics to dilute solutions. The third and 

 fourth lectures are devoted to the atomic theory of matter and 

 to the connection between this theory and the empirical princi- 

 ples of thermodynamics. In the two following lectures the 

 theory of " black-body radiation " is developed ; this is a sub- 

 ject in which Planck was a pioneer and these two lectures con- 

 tain a masterly presentation of a very difficult problem and of 

 the progress which has been made toward its solution. In the 

 seventh lecture, the general application of the Principle of Least 

 Action to all reversible phenomena is discussed ; and the last lec- 

 ture contains a very clear and enthusiastic exposition of Ein- 

 stein's Principle of Relativity. All the lectures are marked by 



