REVIEWS AND NOTICES OF BOOKS. 237 



suggestive discussion on the conduct of experiments with 

 fertilisers. 



It is hardly necessary to add that both books are written in 

 Mr Hall's lucid and attractive style. A. L. 



Les Sols Forest iers. Par E. Henry, Professeur k I'Ecole 

 Nationale des Eaux et Forets. 492 pp., including Table of 

 Contents, with 3 diagrams, 5 plates and 2 maps. 



Les Sols Forestiers, by Professor Henry of the French School 

 of Forestry, Nancy, is a welcome addition to the literature on 

 this subject. Its appearance at the present time is rendered the 

 more acceptable, since general interest in all matters per- 

 taining to silviculture, is now being actively, and it is hoped 

 permanently, revived in this country. There are, however, 

 other reasons which make us welcome treatises on soils; for, 

 like most studies in natural science, considerable progress has 

 been made within the last few decades. Hitherto, soil investi- 

 gations have been mostly directed towards a better understanding 

 of their chemical and physical properties, and in this respect 

 very different views and hypotheses to those originally held 

 are now put forward. It is however, in connection with soil 

 bacteriology that the greatest advances have been made. Since 

 Warington published his brilliant researches on nitrification, and 

 Hellriegel and Wilfarth their important work on nodule-forming 

 bacteria — not to mention the work of numerous other con- 

 tributors—increasing attention has been devoted to soil biology, 

 with the result that its study now forms the most fruitful and 

 fascinating line of work in soil investigation. An admirable 

 survey of modern ideas on soil problems is supplied in the 

 second edition of Mr Hall's book on agricultural soils, and there 

 exist many valuable treatises by other well-known authorities ; 

 but if we turn to forest soils, we cannot but admit that there is a 

 lamentable absence of recent British work dealing specifically 

 with this subject. For this reason Professor Henry's book 

 should form a most valuable help and guide to the student 

 of forestry. The subject matter of the book is contained in 

 18 chapters, occupying 492 pages, and embodies the results 

 of a large number of French, German, Russian and other 

 investigations. Its compilation must have entailed a great 

 deal of labour, for it is amply supplied with explanatory tables, 

 and wherever necessary, references to the source of the 



