AGEICULTUEAL BOTANY. 223 



In Tennessee the vegetation iirounrl the smelter appears from actual chem- 

 ical analysis to be injured over a region approximately 20 miles long by 13 

 miles wide. There is little doubt but that the injury extends beyond the limits 

 mentioned, but this can not be shown by chemical analysis, since the difference 

 in sulphur trioxid observed in specimens of injured and uninjured trees be- 

 comes so small as to be within the results of experimental erroi*. 

 ' The investigations in Montana were conducted to determine whether or not 

 the vegetation is injured by reason of the sulphur dioxid set free by the smel- 

 ters, whether or not enough ai-senic is set free to settle on the surrounding 

 vegetation and poison tlie forage plants so that they are unfit for cattle, and 

 whether or not the waste discharged into the irrigation streams renders the 

 water unfit for irrigation purposes. 



In the first investigation it was found by careful examination that the for- 

 ests were injured over a region at least 22 miles long and 15 or more miles 

 wide. The injury to lodge-pole pines did not extend this far, but red fir was 

 severely injured. An examination was made of leaves from injured and unin- 

 jured trees, and in 92 per cent of all the analyses the leaves from injured trees 

 contained more sulphur trioxid than the uninjured ones. 



As to the amount of arsenic given off by the smelter stacks, arsenic determi- 

 nations were made of 20 samples of range grass, from which it appeared that 

 20 lbs. of the dried forage contained from 3 to 10.9 gm. of arsenic, the amount 

 deperyding on the distance the samples were collected from the smelters. 



From determinations of the effect of the waste from the smelters on the 

 irrigation water, the author concludes that by reason of the large amount of 

 copper discharged it is unfit for irrigation purposes. 



In summarizing his observations the author states that the vegetation around 

 the smelter for at least 7 to 8 miles south and 13 to 15 miles west was severely 

 injured. Junipers are very resistant .to smelter fumes and appear able to grow 

 close to the smelter, red firs are very susceptible and were badly damaged at 

 13 to 15 miles from the smelter, while lodgepole pines appeared intermediate 

 between the other two species, but showed some injuries for at least 10 miles. 

 Large amounts of arsenic are discharged from the smelter on the surrounding 

 country, being present in forage crops in large enough quantities to poison 

 cattle. The waste from the reduction plant renders the water of the Deer 

 Lodge River unfit for irrigation purposes. 



An investigation of the injurious ingredients of smelter smoke, W. C. 

 Ebaugh (Jour. Anier. Chcm. Soc, 20 (1907), ISlo. 7, pp. 951-970, pi. 1, fiff. 1).— 

 An account is given of investigations carried on by the author to determine the 

 effect of smelter smoke on the growth of plants. The investigations were con- 

 ducted in Utah, and in addition to the observations made in the vicinity of 

 smelters, experiments were carried on in fields to determine the effect of sul- 

 phur dioxid on beets and alfalfa. 



In the experiments with alfalfa and beets different numbers of treatments 

 with sulphur dioxid were given the plants, the amoimts varying from 1 part 

 to 10,000 parts of air to 1 part in 50,000. In another series of experiments 

 sulphur dioxid in an aqueous solution was sprayed and poured over plants with 

 injurious effect. The author then took up the action of flue dust on these 

 same species of plants, and found in general that the appearance of the leaves 

 of alfalfa and sugar beets was analogous to that produced when solid particles 

 of flue dust were allowed to fall on the plants. 



The author concludes that sulphur dioxid can not be considered harmless, 

 especially in an inclosed space or in a moist climate, and that the harmful 

 action of the solid emanations, called flue dust, from smelters has been under- 

 estimated. 



14639— No. 3—07 3 



