SOILS — FERTILIZERS. 17 



is now being erected for pressing and drying tlie sludge and for recovering the 

 grease wliicli forms about 30 per cent of the dry product ; tlie dry residue, wliicli 

 contains about 3 per cent nitrogen, to be sold as a fertilizer." At Tadcaster 

 arrangements are being made to liandle the sewage in much the same way as 

 is done at Bradford, " and the product has already been sold in advance for 

 several years to come, to be exported to the United States." 



At Leeds the sludge is used for the manufacture of ammonia gas by de- 

 structive distillation, the ammonia being recovered in the form of ammonium 

 sulphate which has a value of $70 per ton. The residue from the retorts is 

 used for the manufacture of artificial stone or bricks. 



At Oldham the grease is recovered from the sludge by distillation with steam. 

 The dry residue from this process is sold for a small price as a fertilizer. It is 

 thought to have little value for this purpose because a large part of the nitro- 

 gen is driven off in the distillation. 



In Dublin a part of the sewage sludge " is mixed in large tanks with a small 

 proportion of spent brewery yeast and fermentation is started by the aid of hot 

 water pipes. The organic matter separates out and is dried and sold as fer- 

 lilizor in powder fox-m under the name of * Fertilite,' $12 per ton being obtained, 

 and it is understood that there is a large demand for it." 



Sewage sludge disposal, I. Batley {Municipal Engin., Ji2 (1912), No. Jf, pp. 

 227-220). — This article covers unich the same ground as that noted above. 



The private sewag'e disposal plant, J. Van V. Manning (Sci. Amer., 106 

 (1912), No. 15, pp. 3S2, 31,2, SJiS, figs. 6).— Simple systems adapted to the de- 

 tached villa and farm or country house are described. The principal require- 

 ments of those disposal plants are "(1) preliminary treatment of sewage to 

 liquefy solids and suspended Impurities, and hold back grease, scum, and sludge; 

 (2) purification of effluent by natural or artificial filtration; (3) an acre or 

 more of land; and (4) slope sulRcient for sewage to flow by gravity." 



SOILS— FERTILIZERS. 



Soils of the eastern United States and their use, XXIX-XXXV, J. A. 



BoNSTEEL (V. 8. Dept. Agr., Bur. Soils Circs. 5), pp. S; 55, pp. 10; 56, pp. 8; 

 51, pp. 10; 58, pp. 11; 50, pp. 10; 60, pp. IS). — These circulars discuss the fol- 

 lowing soil types with respect to geogx-aphical distribution, characteristics, sur- 

 face features and drainage, use. improvement, and crop adaptations. 



Circular 54 deals with the Crowley silt loam of which a total of 477,120 acres 

 in 3 areas in central Arkansas and southwestern Louisiana has been surveyed 

 and mapped by the Bureau of Soils. 



Rice under irrigation constitutes the great dominant crop on this soil type, 

 and it is stated that since 1SS5 the acreage has grown from practically nothing 

 to hundreds of thousands of acres. 



Circular 55 deals with the Chester loam of which a total of 600,680 acres 

 in 8 areas in southeastern Pennsylvania, central Maryland, and north central 

 Virginia has been surveyed and mapped. 



The surface topography of the Chester loam is described as rolling to some- 

 what hilly and natural drainage is, therefore, well established. Some sections 

 are considerably eroded and should be terraced and maintained in sod during 

 a considerable portion of the crop rotation. 



" The Chester loam is an excellent general-purpose farming soil ; the prin- 

 cipal crops gro'UTi are corn, wheat, oats, rye, potatoes, and hay." 



Circular 56 deals with the Penn loam, of which a total of 320,266 acres in 

 New Jersey, Pennsylvania, Maryland, and Virginia has been surveyed and 



