Febbuabt 17, 1911] 



SGIENCE 



253 



in the preface, it has been written " from the 

 standpoint of organic chemistry." 

 ■ The subject matter is discussed under the 

 following headings: Mechanical Properties, 

 under which are treated Capillarity, Viscosity 

 and Volume Relations; Thermal Properties, 

 including Specific Heat, Fusibility and Boil- 

 ing Point; Optical Properties, including Re- 

 fractive and Dispersive Power, Absorption of 

 Light, Fluorescence and Magnetic Rotatory 

 Power; and Electric Property, including a 

 short chapter on Anomalous Electric Absorp- 

 tion. 



In an introductory chapter, the development 

 of the study of the physical properties is 

 traced and the gradual increase in importance 

 of these properties as aids in determining 

 chemical constitution is clearly brought out. 

 The concluding statement of this chapter that 

 in determining chemical constitution " evi- 

 dence drawn from physical properties should 

 be regarded as subordinate to chemical evi- 

 dence " will be concurred in by most chemists. 

 In the sections dealing with the Mechanical 

 and Thermal Properties, an unsatisfactory 

 impression is obtained at times with regard 

 to the scope of the theoretical treatment as well 

 as the application to the experimental data. 

 On the other hand, in fairness to the author, 

 it must be said that with the space at his dis- 

 posal a more satisfactory treatment of these 

 subjects is scarcely possible. The same criti- 

 cism does not apply to the chapters in which 

 the optical properties are discussed, as here 

 the treatment is clear and complete, especially 

 in describing the relations which have been 

 deduced between absorption and chemical 

 constitution. The additive and constitutive 

 effects exerted by the atoms and groups of a 

 molecule upon each property are carefully 

 distinguished throughout and illustrated by 

 concrete examples. 



The concluding chapter considers the pres- 

 ent status of the subject and the most fruitful 

 lines for further investigations. In the opin- 

 ion of the author, the study of the optical 

 properties, including absorption and refrac- 

 tion, offer the greatest promise, but further 

 advance along these lines depends upon a sat- 



isfactory theory of valence. This, it is pointed 

 out, is the most important problem awaiting 

 solution from the chemist, and "the elec-. 

 tronic theory seems to be the only means by 

 which there is any prospect of attaining 

 further knowledge of the nature of valence." 

 E. G. Falk 



Chemische Krystallographie. By P. voN 



Groth. Leipzig, Wilhelm Engelmann. 



1910. Vol. 3. Pp. iv+804, 648 figures; 



Svo, cloth, 30 Marks. (Volume IV. is in 



preparation.) 



In 1904 Professor P. von Groth, of the 

 University of Munich, published his " Ein- 

 leitung zur Ghemischen Krystallographie," 

 and followed it two years later with the first 

 volume. In 1908 the second volume of the 

 " Chemische Krystallographie " was issued. 

 These volumes have aU been reviewed in 

 Science.' 



Groth's " Chemische Krystallographie " is a 

 work of monumental proportions, and is to 

 include the crystallographic data of all sub- 

 stances which have been described at the time 

 of the publication of the individual volumes; 

 Inorganic compounds were discussed in vol- 

 umes I. and II. The third and fourth vol- 

 umes are to he devoted to organic compounds. 

 In volume III., which has just been published, 

 crystallographic data are given for the ali- 

 phatic carbon compounds, hydrobenzol deriva- 

 tives and terpenes. The method of treatment 

 in this volume is the same as in the others, 

 according to which all substances having a 

 similar chemical composition are placed to- 

 gether and their descriptions prefaced by a 

 discussion of the work done on the group. 

 These discussions are suggestive as well as 

 critical in character and mal^e the work of 

 much more value than a mere compilation of 

 chemical crystallographic data could be. This 

 volume, as well as volume IV., which it is 

 hoped will be published before long, ought to 

 prove of especial value to organic chemists. 

 Edward H. Kraus 



MlNEEALOGICAl LABOBATOET, 



University of Michigan 

 'Vol. XXV., 143-144; Vol. XXVIII., 843. 



