24 EXPERIMENT STATION RECORD. 



is attributed to the effect or xreezing in overcoming the depressing influence of 

 the crops previously grown. 



The accumulation of green manure nitrog-en in sandy soils, C. von Seel- 

 HOEST ET AL. (Avb. Deut. Landw. OeselL, 1913, No. 241, pp. W, pis. 20).— A 

 summary of the results of 6 years' experiments in vegetation tanks, here re- 

 ported in detail, has previously been noted (E. S. R., 20, p. 224). 



Manures and fertilizers, H. J. Wheeler (New York, 1913, pp. XXI-{-589, 

 pi. 1, figs. 62). — This is the ninth volume in The Rural Text-book Series, edited 

 by L. H. Bailey. 



The author states that " the preparation of this volume was undertaken 

 for the purpose of meeting a distinct lack in collegiate agricultural text- 

 books in the United States. It was hoped to prepare a book reasonably 

 free from extended details, such' as are found in certain of the larger foreign 

 works, and likewise to avoid the rather superficial treatment of the subjects 

 which has necessarily characterized many of the books which have been writ- 

 ten for the purpose of meeting the earlier requirements of the American agri- 

 cultural colleges, and the present demands of agricultural high schools. The 

 intent has been to provide in a measure for the needs of the graduate student 

 in agriculture; also for the requirements of students in the agricultural col- 

 leges, teachers in agricultural schools, graduates of agricultural schools and 

 colleges, agricultural institute lecturers, and the rapidly increasing number of 

 intelligent men who are daily interesting themselves in the scientific phases of 

 modem farming." 



In a historical introduction the author gives in a few pages a summary of 

 the major steps in the scientific development of the use of manures and fer- 

 tilizers. Then follow chapters dealing with night soil; the dung of farm 

 animals and its preservation; the organisms and fermentation of dung; the 

 practical utilization of manures; sea weeds; guanos; fish, crab, lobster, and 

 similar wastes; common slaughter-house nitrogenous waste products; other 

 miscellaneous nitrogenous substances; the availability of organic nitrogen and 

 factors affecting it ; calcium and potassium nitrates ; nitrate of soda ; ammonium 

 salts and calcium cyanamid; natural phosphatic fertilizers; manufactured 

 phosphates and studies of solubility ; potassic fertilizers ; the theory and prac- 

 tice of potash fertilization ; lime and its relation to soils and fertilizers ; liming 

 in its relation to plants; gypsum and waste lime from industries; magnesia as 

 a fertilizer; sodium salts; iron and manganese; and chlorin, sulphur, silica, 

 carbon disulphid, toluene, and other miscellaneous substances. 



In the discussion of many important features of the subject the author has 

 drawn freely upon the results of his ovm well-known investigations relating 

 to plant nutrition and soil requirements at the Rhode Island Experiment Sta- 

 tion because, as he observes, " he can speak of these results in a more authori- 

 tative way than of work done elsewhere," and because " the work has been, 

 in some respects, of a pioneer character, and has not been duplicated." 



Some of the subjects which are perhaps more fully treated than in most 

 text-books of this kind are guano and human excrement (largely historical) ; 

 seaweed (not, however, dealing with the recent exploitation of Pacific coast 

 seaweeds as a source of potash) ; the bacterial changes in animal excrements; 

 the relative availability of nitrogenous manures; the relative value (especially 

 cumulative and indirect effects) of nitrates and ammonium salts; the new 

 synthetic nitrogenous fertilizers — calcium cyanamid and calcium nitrate; and 

 the function in soil improvement and plant growth of lime, magnesia, soda, 

 manganese, and various catalytic fertilizers. 

 The book is well indexed. 



