In this table, with possibly two or three exceptions, it will be noted that the soils close to the smelters contain very nearly the same amounts of sulphur trioxid as those farther away, so that in comparing injured trees situated near the smelter with uninjured trees at a greater distance the soils in which they grew may be considered identical. Out of 49 such comparisons it will be noted that 46 times, or in 94 per cent of the cases examined, the sulphur trioxid content of the injured trees is larger than that of the uninjured trees of the same species situated beyond the range of the seemingly significant damage and that in 40 cases, or 82 per cent of the number examined, the sulphur trioxid content of the ash of such injured trees is larger than that of similar uninjured trees situated beyond the range of apparent damage. In a northerly direction in 100 per cent of the cases examined the leaves of the injured trees contain a larger percentage of sulphur trioxid than the leaves of the uninjured trees and in 81 per cent of the examinations the ash of such injured trees contains a larger percentage of sulphur trioxid than the ash of the uninjured trees. In an easterly direction in 100 per cent of the cases examined the leaves of the injured trees contain a larger percentage of sulphur trioxid than those of the uninjured trees and in 75 per cent of the cases examined the ash of such injured trees contains a larger percentage of sulphur trioxid than the ash of those uninjured. In a southerly direction in 77 per cent of the cases examined the leaves of the injured trees contain a larger percentage of sulphur trioxid than the leaves of the uninjured trees and in 69 per cent of the examinations the ash of such injured trees contains a larger percentage of sulphur trioxid than the ash of those uninjured. In a southerly direction, if only those trees are considered which were within a distance of 6 miles from the smelters, it appears that in 88 per cent of the cases examined the leaves of the injured trees contain a larger percentage of sulphur trioxid than those of the uninjured trees and in 100 per cent of the examinations the ash of such injured trees contains a larger percentage of sulphur trioxid than the ash of those that are uninjured. In a westerly direction in 100 per cent of the examinations both the leaves and the ash of the injured trees show a larger content of sulphur trioxid than do the leaves and the ash of the uninjured trees. From this investigation the following conclusions are drawn in regard to the distribution of the injury by smelter fumes: (1) The vegetation around the smelters appears from actual chemical analysis to be injured for at least 12 to 12 miles north of the smelters, 6 miles south, 5 to 6 miles east, and 9 miles west. (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 animal 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 running 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 practiced, 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 surrounding 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 applied. 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 chemical 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 common 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 of Deer Lodge Valley and Warm Springs Creek Valley, and is near the Hell Gate and Helena National Forests and certain other public lands. To the north, south, east, and west of this valley are quite high ridges of mountains which are cleft here and there by the valleys of small creeks, of which Warm Springs Valley is one of the largest. Down the center of Deer Lodge Valley runs the river of that name, into which is carried part of the tailings and slag from the plant and the wash from the dumps and slime heaps. As before mentioned, this river is used for irrigation purposes, although a large number of the farmers say that it is injurious and prefer to get their water from small creeks coming down from the mountains on either side, only using the river water when it is absolutely necessary. It is only near the tops of ridges and beyond them and along the valleys of the various small streams that the land is forested to any extent. Besides this, forest fires have swept over certain of the mountains in the past, so that all dead timber can not be ascribed to sulphur dioxid from the smelter. However, enough trees remain within a radius of 10 to 15 miles from the smelter, which have not been injured in any way by the forest fires, crowding, insect pests, etc., to enable one to observe the damage caused by sulphur dioxid. The three principal kinds of trees in the neighborhood of the smelter are the lodgepole pine, juniper, and red fir. The difference in their resistance to sulphur dioxid fumes is very marked and can easily be observed. Immediately surrounding the smelter practically all trees are either dead or severely injured. A very few trees still stand, to which those who do not believe in the injurious effects of smelter fumes point with pride as examples of the fact that sulphur dioxid does not injure vegetation. Since, however, hundreds of the same kinds of trees are killed outright at ten times the distance from the smelter, the force of the argument is entirely lost and the few seemingly uninjured trees near by only appear to a disinterested person as curious examples of individual resistance. NORTH OF THE SMELTER. Going north from the smelter a trip was first made from Anaconda in a direction slightly east of north, until the road running along the east side of Deer Lodge River was reached. This road was followed to the vicinity of Race Track. Here the river was again crossed and the road running on the west side of the Deer Lodge River was followed as far as Deer Lodge. On the return the same route was followed, except that the trip along the east side of the river was continued farther south to a point beyond J. R. Perdee's ranch. Various samples of cattle-food materials, soils, and Deer Lodge water were collected and observations on the general appearance of the vegetation were made. It was noted that the bushes and trees along the streams |