INVESTIGATION AT ANACONDA, MONT. alt 
(2) There can be but little doubt that the injury extends beyond 
the limits mentioned in the preceding paragraph, but this can not be 
shown by chemical analysis, since the difference in sulphur trioxid 
content between injured and uninjured trees becomes so small as to 
be within the limits of experimental error. 
FIRST INVESTIGATION OF INJURY BY SMELTER WASTES 
AROUND ANACONDA, MONT., 1906-1907. 
A third extremely important study of injury to vegetation and ani- 
mal life by smelter wastes was conducted by the writer in the country 
surrounding Anaconda, Mont., and at Washington during the latter 
part of 1906 and the whole of 1907. In the immediate vicinity of 
Anaconda the huge Washoe smelter is situated, roasting, when run- 
ning at full head, from 8,000 to 10,000 tons of ore per day, which 
ore is said to contain quite large quantities of arsenic. (See Pl. V.) 
The plant is situated in a semiarid country, where irrigation is 
vracticed, and discharges its tailings and slags into certain of the 
streams that are used for irrigation purposes. There are therefore 
three distinct problems to be worked out in connection with the 
injury caused by the smelter: 
(1) Whether or not the vegetation is injured by reason of the 
sulphur dioxid and trioxid set free. 
(2) Whether enough arsenic is set free to settle on the surround- 
ing forage plants to make them unfit for stock. 
(3) Whether the waste when discharged into the irrigation 
streams renders the water unfit for irrigation purposes and injures 
the soil to which such water is apphed. All of these problems were 
studied, and definite data bearing thereon obtained. 
The chemist in this investigation was accompanied by one of the 
foresters of the Department of Agriculture. Samples of soil, foliage 
of trees, forage plants, irrigation waters, ores, and of the dump heap 
were collected and forwarded to the Bureau of Chemistry for chem- 
ical examination. As in the Tennessee investigation, samples of 
foliage were collected from those trees which the forester was certain 
had not died from insect pests, forest fires, crowding, or other com- 
mon causes of forest destruction. 
A few paragraphs of introduction are necessary in regard to the 
situation of the smelter and the appearance of the surrounding 
country. 
LOCATION OF SMELTER AND APPEARANCE OF SURROUNDING 
: VEGETATION. 
The Washoe smelter is situated on a high hill toward the southern 
end of Deer Lodge Valley, which is about 35 miles long and from 4 
to 6 miles wide. (See Pl. VI.) It is located about at the junction 
