512 EXPERIMENT STATION RECORD. 



past few decades to tlie provision of suitable water supplies and the adequate 

 disposal of sewage, renders the present critical survey of modern methods . . . 

 useful to the English reader." 



The first half of the book Is devoted chiefly to modern processes of puri- 

 fication of water for drinking purix)ses on both large and small scales. The 

 purification of water for industrial purposes is also briefly touched. The 

 second half discusses the mechanical and biological purification and disposal 

 of domestic sewage, particularly noting the advantages and disadvantages of 

 sewage farming and the use of screen and grit chamber residues and sludge as 

 fertilizers. 



The main purpose of the process of sewage farming is considered to be 

 sewage purification rather than agricultural benefit, and " it is inadvisable on 

 this account for towns to lease their sewage farms to farmers. ... In all 

 circumstances purification of the sewage before disposal on the farm is to be 

 recommended." The residues from grit chambers and screens are said to con- 

 tain some plant food elements and may be used as fertilizers though such use 

 is usually offensive. Sludge from sedimentation tanks Is said to contain (in 

 dry matter) generally from 2 to 3 per cent nitrogen, about the same amount 

 of phosphoric acid, and about 0.5 per cent potash, but owing to its foul condi- 

 tion and the difficulty and expense of drying, its use as a fertilizer is limited. 

 The purification of industrial sewage is also discussed in some detail. 



Scientific sewage and garbage disposal (Daili/ Cons, and Trade Rpts. 

 [U. 8.], It {191If), No. 29, pp. U9-459).— The methods of sewage and garbage 

 disposal practiced in various places in the United Kingdom, Germany, France, 

 Austria, and Russia are briefly described. It is shown that sewage irrigation 

 and the utilization of sludge and certain garbage products as fertilizer is suc- 

 cessfully practiced in many places in these countries, but generally, however, 

 in connection with other methods of disposal. 



Sewage sludge disposal {Chem. Trade Jour., 5If {1914), No. 1391, pp. 71-73, 

 pgg^ 5). — The Grossmann process of treating sludge to free it from fat and fit it 

 for use as a fertilizer, as applied at Oldham, England, is described. 



The Cairo sewage farm at Gebel el Asfar, E. C. B. Smith (Agr. Jour. Egypt, 

 3 {1913), No. 1, pp. 23-27, pis. 4). — ^This article describes and illustrates by 

 ground sections the geological features and formations of the sewage farm as 

 determined by test borings which indicate its fitness for sewage irrigation. 



SOILS— FERTILIZERS. 



Agricultural chemistry — chemistry of the soil, G. Andr^ {Chimin Agricole- 

 Chimie du Sol. Paris, 1913, pp. XVI-\-556, figs. 9). — ^This is one of the volumes 

 of Wery's EncyclopMie Agricole. It is more than its title indicates, for it dis- 

 cusses the formation, classification, and physical and biological properties of 

 soils as well as the more strictly chemical features of the subject. 



The treatment of the subject is encyclopedic, and the book contains a large 

 amount of information drawn from many sources which, however, are often 

 not so clearly indicated by citation of references as the investigator could 

 wish. 



The historical development of certain phases of soil investigation is quite 

 fully treated in some cases, but is not always brought up to date. This is 

 notably true in the discussion of the chemistry of the organic matter of the 

 soil in which no account is taken of the recent important work by American 

 investigators. 



Methods and aims of soil investigation and teaching, E. Blanck {Fiih- 

 ling's Landiv. Ztg., 62 {1913), No. 13, pp. ^62-473; ahs. in Zenthl. Agr. Chem., 



