716 EXPERIMENT STATION EECOED, 



important results of general interest obtained in six years' investigations of 

 conditions in Chicago, more particularly with reference to recommending means 

 of smoke abatement. The article also reviews the more important literature 

 of atmospheric pollution, and the methods employed are described. 



The investigations showed that " in general, the combination of meteoro- 

 logical conditions which tends to intensify the effects of polluting substances 

 in the air includes low wind velocity, comparatively low temperature, high 

 relative humidity, and absence of sunshine." It was found that the quantity 

 of solid materials, derived both from fuel consumption and from dust, in the 

 atmosphere of Chicago varied from 0.321 to 1.9.jS mg. per cubic meter. The 

 suspended matter in the air consisted not only of solid products of combustion 

 but also of mineral, vegetable, and animal debris. While the amount and char- 

 acter of the solids in smoke varied greatly, smoke arising from solid fuels 

 was never free from such solids, and, moreover, the amount discharged had no 

 direct relation to visibility. The amount of carbon dioxid found did not vary 

 materially from that of the air of other cities. The ammonia content of the 

 air was .small and only insignificant amounts of chlorin were found. The 

 amount of sulphur compounds varied from 0.217 to 1.104 mg. per cubic meter. 



Sulphur dioxid content of the atmosphere of the smoke zone [of tlie Selby 

 smelter, California], J. A. Holmes, E. C. Feanklin, and R. A. Goixd (T. S. 

 Dept. Int., Bur. Mines Bui. 98 {1915), pp. 26-39).— The results of 4,862 deter- 

 minations of sulphur dioxid at two stations, selected with a view to ob- 

 taining the maximum sulphur dioxid content of the air in the smoke zone 

 of the Selby smelter in Contra Costa County, Cal., are reported and discus.<;ed 

 with reference to the question as to whether the i^ulphur dioxid constituted a 

 nuisance as regards objectionable odor or effect iiptin the mucous membrane 

 linings of the throat and lungs of human beings and domestic animals. 



The maximum content of POj found during eight month.s' observations was 

 7.1 parts per million. This was found, however, under exceptional conditions. 

 The average content calculated from all observations was 0.22 parts per million, 

 and the average for conditions considered favorable for high concentration 

 was 3.6 parts per million. The sulphur dioxid content of the air of a number 

 of California cities and other places outside of the smelter zone is reported 

 for comparison, and shows a considerable percentage of sulphur dioxid in 

 places where no smelters or works of similar character exist. For example, it 

 was found that under certain conditions the sulphur dioxid content of the air 

 of San Francisco reached nearly 2 parts per million. 



Considering the data as a whole, the conclusion is reachotl that the sulphur 

 dioxid content of the smoke zone of the smelter is not sufficient to constitute 

 a nuisance from the standpoint of its direct effect upon man. 



Investigations to determine the extent of the contamination of the atmos- 

 phere in the Selby " smoke zone " by the smelter emanations, A. E. Wei.ls 

 {U. S. Dcpt. Int., Bur. Mines Bui. 08 (1915), pp. 82-212. pis. 4. figs. 5).— This is 

 a detailed account of metliods employed and the results observed in the in- 

 vestigations of which the more general results are summarized in the article 

 noted above. 



SOILS— FERTILIZERS. 



A student's book on soils and manures. E. .1. Rvssell (Cambridfjc, Enffland: 

 Camhridfte UnivcrsHii Press, 1915, pp. IX +206. figs. 34). — This number of the 

 Cambridge Farm Institute series is a rather popular treatise on soil manage- 

 ment which is divided into three parts. 



