Januabt 20, 1911] 



SCIENCE 



lii 



tree is cut, measures shall be enforced whieli 

 will produce another tree " (p. 262) — these 

 are typical expressions. 



The book is an outgrowth of a series of 

 twenty lectures, and the arrangement and 

 style reflect the original presentation; there 

 are occasional discontinuities and other minor 

 imperfections which systematic construction 

 in the study would have obviated. In view of 

 that trenchant application of the quantitative 

 method which the conservation movement ex- 

 presses, it is unfortunate that the indefinite- 

 ness of thought and cloak for sharp practise 

 involved in the " long ton " should find ex- 

 pression, still less the rhetorical monstrosity, 

 " short ton " ; as if there were in well-chosen 

 American terminology any " short " ton — save 

 that delivered by a dishonest dealer. A mis- 

 leading expression is " reserves," applied to 

 natural supplies — a term unhappily intro- 

 duced in this country by a foreign student 

 and carelessly adopted through mimetic in- 

 stinct ; there is indeed a " gold reserve," and 

 there have been " forest reserves," but there 

 are unfortunately no coal reserves or iron 

 reserves in the United States — and the very 

 use of the term tends to confuse thought and 

 thereby retard desirable action. 



On the whole, despite the few minor blem- 

 ishes sure to disappear in later editions, Van 

 Hise's book is a highly useful summary of the 

 facts and statement of the principles involved 

 in the conservation movement; and its issue 

 would seem to meet an urgent need. 



W J M. 



Theoretical Principles of the Methods of 

 Analytical Chemistry Based upon Chem- 

 ical Reactions. By M. G. Chesneau. Au- 

 thorized translation by Azariah Thomas 

 Lincoln, Ph.D. and David Hobart Carna- 

 han, Ph.D. New York, the Macmillan 

 Company. 1910. Pp. x -f 184. $1.75 net. 

 The book attempts to show that the phe- 

 nomena and methods of analytical chemistry 

 ■can be established on a theoretical basis of 

 thermochemical data and thermodynamic 

 principle, without the use of the electrolytic 

 -dissociation theory. In other words, it repre- 



sents a systematic attempt at practical appli- 

 cation of the views held by opponents of the 

 dissociation theory, notably by Professor 

 Kahlenberg. 



It is divided into seven chapters. The first 

 examines " the influence of the physical state 

 of precipitates upon their purification by 

 washing (size of grains, crystalline state, col- 

 loidal state)." The second chapter deals with 

 the principal types of irreversible reactions 

 used in analysis and with the theoretical prin- 

 ciples involved. The third chapter deals with 

 reversible reactions from the thermodynamic 

 standpoint, carefully avoiding the use of the 

 electrolytic dissociation theory: ionic con- 

 centrations are absent from the mass law 

 equations, the molar concentrations being 

 raised to empirical fractional powers (Van't 

 Hoff's coefficient i). The fourth chapter in- 

 troduces the theory of solutions and includes 

 a brief statement of the principal facts upon 

 which the dissociation theory rests. The 

 fifth chapter is devoted to an attempt to show 

 that the dissociation theory can no longer be 

 maintained in science and that it is decidedly 

 overthrown by the work of Kahlenberg. The 

 sixth chapter deals with analytical processes 

 based upon double decomposition of salts. 

 Here for the first time the principle of con- 

 stancy of the solubility product is stated, then 

 an attempt is made to show that it can be dis- 

 pensed with, not only without loss, but with 

 gain. In the last chapter we find, as a substi- 

 tute for the Ostwald theory of indicators, one 

 based upon " thermochemical data and the 

 hydrolysis of salts in solution " and having 

 " its origin in the principles set forth by 

 Berthelot in his Thermochimie" (p. 167). 

 We read here that the change of color of an 

 acid indicator is due to the difference in color 

 between the free acid and its alkaline salt. 



On page 127 we read : " If the contradic- 

 tions between the facts and the theory of 

 ionization appear to require the rejection of 

 the latter, one falls then into another difii- 

 culty, that of not explaining the necessity of 

 introducing the coefficient i into the general 

 law of equilibrium of Guldberg and Waage." 

 The author thinks, however, that the molecular 



