BOOKS AND CURRENT LITERATURE 



Report of the Selby Smelter Commission. — This Commission, 

 appointed by agreement between litigants in the CaHfornia courts to 

 examine into alleged agricultural and other injuries produced by smoke 

 from the Selby Smelter, near San Francisco, made its report in No- 

 vember, 1914, and the report has now been published in full by the 

 U. S. Bureau of Mines. ^ Many of the data presented are of local appli- 

 cation only but certain features have general interest and some of these 

 are important to botanists. Of special interest are the extensive and 

 thorough studies of the effect of sulphur dioxide on barley plants con- 

 ducted by Mr. A. E. Wells, INIetallurgist and Chief Chemist of the Com- 

 mission, and reported on pages 213 to 307 of the Bulletin cited. There 

 is a brief summary of this work with the conclusions of the Commis- 

 sion on pages 39 to 46. Experiments were conducted in the field at 

 two localities in California and a total of 141 plots 20 by 4 feet in area 

 and containing barley plants growing under field conditions were sub- 

 jected to fumigations with air carrying known amounts of sulphur 

 dioxide between 1 part and 20 parts per million. The action on the 

 plants, if any, was judged by visible injury and by the effect on the 

 yield. 



It was found that the occurrence and severitj^ of injury is deter- 

 mined mainly by three factors: the concentration of the sulphur dioxide 

 in the air, the length of time during which it is applied, and the hu- 

 midity. When the time between applications was short, intermittent 

 application produced practically the same effect as continuous applica- 

 tion for the same total time. When the time between applications was 

 relatively long the effect of intermittent application was less severe 

 than that of continuous application. For the same concentration and 

 time of application injury is greater the higher the humidity. There 

 are innumerable combinations of concentration, time of application 

 and humidity which will produce injur}^ The ''toxic limit" of con- 

 centration must be defined with relation to both of the other factors. 

 The Commission believes it possible to produce injury by the continu- 



1 Bureau of Mines, Bulletin 98, 520 pp. 1915. The Commissioners were the 

 late Dr. J. A. Holmes, Dr. Edward C. Franklin of Stanford University and Mr. 

 Ralph A. Gould, of San Francisco. 



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