262 BOOKS AND CURRENT LITERATURE 



In heavy soil the roots were confined to the upper soil layers. In light 

 soil the roots penetrated deeply and extended widely. In soil of an 

 intermediate character the root development was also intermediate. 

 The results were confirmed bj^ the growth of gram with fragments of 

 broken pottery added to the soil. In all cases soil which was provided 

 with good aeration induced the type of root development that had 

 already been observed in well aerated soil. Howard makes the inter- 

 esting generalization that the distribution of gram, as a crop follows the 

 occurrence of well aerated soils. 



The effects of inadequate aeration of the soil on crops of various 

 kinds at Quetta are similar to the effects seen at Pusa, pointing to the 

 undoubted general application of these conclusions in agriculture and 

 in plant ecology. This has been pointed out recently^ and additional 

 research only serves to emphasize its importance. — W. A. Cannon. 



The Book of Forestry. — The Book of Forestry^ is not for the 

 technical forester nor the ecologist, but for the lay reader who wants 

 information about forestry and conservation. The author's aim is to 

 "awaken the love of the forest in the heart of young America, and a 

 realization that forestry is necessary for the comfort, health, and 

 prosperity of future generations." The book is divided into two parts. 

 In the first part the author crowds into 177 pages a mass of facts, 

 figures and information covering forest influences, conservation of 

 natural resources, forest growth, uses and properties of woods, silvi- 

 culture, forest protection, timber estimating, lumbering, timber pres- 

 ervation and city forestry, with a chapter on the life of a forester 

 thrown in. Under each heading enough is presented to give a reason- 

 able idea of the subject. The second part contains brief descriptions 

 and drawings of some of the more important American trees, and a key 

 for identifying woods. In the appendix is given a table of uses of the 

 principal American species, together with the range and maximum 

 size of the tree, a sample volume table and log scale, a very short list 

 of reference books in forestry, and a glossary of terms. A popular 

 book does not require precision of statement, provided a correct im- 

 pression is left with the reader, and, because of the difficulties inherent 

 in this form of writing, we should overlook unimportant slips. But 



1 Cannon, W. A. and E. E. Free. The Ecological Significance of Soil Aeration. 

 Science, 44: 178. 1917. 



2 Moon, P. F. The Book of Forestry, Pp. 315, figs. 64. New York, D. 

 Appleton and Company, 1916. ($1.75). 



