- Geology and Mineralogy. 333 



6. Allen's Commercial Organic Analysis. Volume IV. 8vo, 

 pp. 466. Philadelphia, 1911 (P. Blakiston's Son & Co.).— This, 

 the fourth volume, of the entirely rewritten fourth edition of 

 " Allen," treats of Resins, India Rubber, Rubber Substitutes and 

 Gutta-Percha, Hydrocarbons of Essential Oils, and Volatile or 

 Essential Oils. The importance and excellence of the work are 

 so well known that no comments in regard to details seem to be 

 necessary, except the statement that the present volume appears 

 to maintain the high standard of the preceding ones. h. l. w. 



7. The Absorption Spectra of Solutions ; by Harry C. Jones 

 and W. W. Strong. Pp. 159 with 98 plates. Publication No. 

 130, Carnegie Institution of Washington, 1910. — This investi- 

 gation is a continuation of the work of Jones and Uhler which 

 was begun in 1905 and subsequently greatly extended by Jones 

 and Anderson. (See Carnegie Publications Nos. 60 and 110; also 

 this Journal, vol. xxviii, page 78.) 



The first chapter of this monograph is devoted to a brief but 

 excellent classification of the various types of spectra, to some of 

 the theories of spectra, and to the methods best suited for study- 

 ing specific spectroscopic problems. Chapter IL deals with the 

 apparatus used in the present investigation. The remaining ten 

 chapters give in detail the variations in the absorption spectra of 

 solutions of certain salts of potassium, cobalt, nickel, copper, 

 chromium, erbium, praseodymium, neodj^mium, and uranium 

 which are caused by chemical agents and by changes of temper- 

 ature. 



The quantity of work done is very great, since about 3000 

 solutions were investigated. The quality of the work is of the 

 first class, as can be readily seen both from the text and from the 

 98 plates. The results obtained are too numerous to be recorded 

 in a brief review. Suffice it to say that well-defined " solvent- 

 bands "have been discovered for water, the alcohols, acetone and 

 glycerol, and that all of the results seem to confirm the hypoth- 

 esis of solvation as developed and emphasized by Jones. 



H. S. XT. 



II. Geology and Mineralogy. 



1. Indiana. Department of Geology and Natural Resources. 

 Thirty-fourth Annual Report. W. S. Blatchley, State Geol- 

 ogist. 1909. Pp. 392, with numerous maps, photographs, tables, 

 etc. Indianapolis, 1910. — The soil survey of Indiana, begun in 

 1907, was continued during 1909 by A. E. Taylor and C. W. 

 Shannon, and the statement of the important results of their work 

 fills the larger part of the present volume. During the three 

 seasons in which the work has been carried on, thirty-three 

 counties in the southern part of the state have had their soils 

 classified, mapped, and treated in detail. It is proposed to go on 

 until the entire State has been similarly treated. The Survey 



