Januakt 15, 1904.] 



SCIENCE. 



103 



cepts of Physical Science ' ; III., ' The Gen- 

 eral Principles Relating to Matter/ and IV., 

 ' The General Principles Relating to Energy.'' 

 To these are added a good general index. 



The basal importance of the subjects with 

 which these chapters have to do is well estab- 

 lished and the author has achieved a signal 

 success in the clear and comprehensive man- 

 ner in which he has presented them to the 

 reader. 



For this is no rehash of what has been al- 

 ready well said by various authors on these 

 subjects, but is clearly the result of a close 

 personal inquiry into the underlying con- 

 cepts of modern science. The reader is thus 

 not infrequently asked to set aside the tradi- 

 tional form in which some concept has been 

 hitherto expressed. The author's independence 

 of thinking is well illustrated in his treat- 

 ment of compounds and mixtures, kinetic and 

 gravitational energy and the second law of 

 thermodynamics. 



Sometimes, however, an impression is left 

 on the reader that the author's restatements of 

 old laws are a little hasty and so lack the ab- 

 solute singleness of idea or exact precision 

 which should characterize any general state- 

 ment in physical science. 



Thus on page IIY we find Faraday's laws of 

 electrolysis expressed as follows : ' The pas- 

 sage of electricity through an electrolyte is at- 

 tended at each electrode hy a chemical change 

 involving a nuinber of chemical equivalents 

 strictly proportional to the quantity of elec- 

 tricity passed through, and dependent on that 

 alone.' This is hardly free from possible mis- 

 understanding. A clearer statement of the 

 facts, following the suggestion of the author, 

 would be the following: The passage of elec- 

 tricity through any electrolyte is attended by 

 chemical changes which involve the same num- 

 ber of chemical equivalents at each electrode, 

 and which are directly proportional to the 

 quantity of electricity passed through and 

 dependent on that alone. 



Similarly on page 37 the statement of the 

 law of multiple proportion would be clearer 

 if the words the same were replaced by the 

 words a given, so that the law would read: 

 ' When one element combines with another in 



several proportions to form different chemical 

 compounds, the quantities of the one element 

 which in the several compounds are combined 

 with a given quantity of the other element, 

 stand to one another in the ratio of small 

 whole numbers.' 



The chapter on energy is especially valu- 

 able. Throughout, the concept of energy is 

 regarded as fundamental and the concept of 

 force is made secondary. The treatment of 

 the various forms of energy is such as to 

 bring into prominence the factors of a par- 

 ticular form of energy — namely the intensity 

 and quantity factors. 



The first and second laws of thermodynam- 

 ics or energetics, as our physical chemistry 

 friends are pleased to call them, are presented 

 and discussed with great distinctness. 



Credit also should be given the author for 

 his consistent use throughout the book of a 

 particular and distinct symbol or letter to 

 denote a particular and distinct physical quan- 

 tity. This saves the beginner many pains. 

 Beginners will owe him also much gratitude 

 because he has made such free use of numer- 

 ical examples to illustrate the applications of 

 the various principles. 



It is a pleasure to say that the present in- 

 troductory volume is a positive addition to 

 the literature of physical science and the 

 students of physical chemisti-y, especially in 

 America, will await with eagerness the ap- 

 pearance of the volumes which are to follow. 

 E. H. LooMis. 



Princeton Univeksity, 

 December, 1903. 



SOIENTlFrC JOURNALS AND ARTICLES. 

 The December number of the Bulletin of 

 the American Mathematical Society contains : 

 Report of the Boston Colloquium of the Amer- 

 ican Mathematical Society, by F. N. Cole; 

 ' Linear systems of curves upon algebraic sur- 

 faces,' by IT. S. White; 'An expression of 

 certain known functions as generalized hyper- 

 geometric functions,' by E. T. Whittaker; 

 ' On the factoring of large numbers,' by F. N". 

 Cole ; ' Note on the p-discriminant of ordinary 

 linear differential equations,' by Arnold Emch ; 

 ' Hydrodynamic action at a distance,' by E. B. 



