REVIEWS 69 



The fact that by 1894 a bill was passed by both Houses of Congress 

 creating a Forest Service for the administration of not only the exist- 

 ing forest reservations, but of all federal timberlands, which failed by 

 a legislative accident, should at least have been mentioned. 



A misconception is created on page 16 by coupling the appropriation 

 for the Division of Forestry with a reference to the Reserves, for the 

 two had no relation to each other. 



Incidentally, we may correct the date of one of these incidents, 

 namely, the beginning of the timber physics work, on page 12, which 

 should be 1888. 



From the standpoint of the bookmaker, we find the printer's work 

 excellent, the volume well illustrated, and the publishers' part as is to 

 be expected from the Macmillan Company, but we do not think it a 

 wise arrangement of material to let an introduction of 50 pages, roman 

 numbers, be followed by 19 pages of contents before the real reading 

 begins. This arrangement confuses the reader and also leads to un- 

 necessary repetition. The absence of an index is only partly offset by 

 a very full table of contents. 



These criticisms are, however, only of minor points in an otherwise 

 excellent book. B. P. K. 



B. E. F. 



Soil Nitrification in Relation to Forest Reproduction. Henrik Hes- 

 selman, Skogsvordsforeningens Tidskrift, Haft i, January. 1918, pp. 

 1-104. 



In a lengthy and richly illustrated article Hesselman, of the Swedish 

 forest experiment station, discusses the fixation of nitrogen in forest 

 soils in its relation to forest reproduction in Sweden. For several 

 years he has been studying the pine heaths of northern Sweden, where 

 reproduction is especially difficult. Early investigations convinced him 

 that the difficulty could not be attributed to lack of moisture. He 

 therefore turned his attention to chemical conditions in the forest floor. 

 Where reproduction is lacking, its failure is generally attributed to the 

 fact that under certain conditions the organic matter of the forest 

 floor is not converted into available nitrogen. These conclusions are 

 based upon numerous chemical analyses of soils and plants under dif- 

 ferent forest conditions. 



Two general classes of forest soils are recognized. In one the trans- 

 formation of organic matter into available nitrates is complete, while 

 in the other the process stops with the formation of ammonia. To the 



