14 | INJURY BY SMELTER WASTES. 
in the open, made during 1907 since Bulletin 89 was published, give 
the following results: 
TABLE 1.—Effect of fumigating trees growing in the open with varying strengths 
of sulphur dioxid, as shown by the sulphur trioxid determined in the foliage. 
[Caleulated to dry basis.] 
: Ashin | Sulphur trioxid— 
Serial Description. dry 
. leaves. jIn leaves.| In ash. 
Per cent.| Per cent.| Per cent. 
5282 | Black oak treated with sulphur dioxid 1:1,000_____-__________ 3.89 0.70 17.99 
5283 4|2 BlackcOak- used: aS COREL ae ae ee ae ee ee eee 3.68 .59 16.03 
5284 | White oak treated with sulphur dioxid 1:1,000________________ 6.49 2.01 30.97 
5285: | =Wihite7Oak: Sed aS | COn ERO ts ete eer = ieee 5.94 57 9.59 
5286 | Cedar treated with sulphur dioxid 1:1,000____________________ 5.46 48 8.79 
5286) (Cedar USCAAS 160 TVET O Pane ee aoe aa eae Pe 6.06 35 5.77 
5288 | Chestnut treated with sulphur dioxid 1:1,000_________________ 4.49 1.44 32.07 
5289 fChestnutased.as controln ae ee n 4.60 56 EASES 
5290 | Black oak treated with sulphur dioxid 1:10,000_______________ 4.00 73 18.25 
529¢ || “Black. oakvused :as Control 3222 Bo ee ee ee ee eee | 5.30 .06 10.09 
5292 | White oak treated with sulphur dioxid 1:10,000______________. 5.02 .69 1 
5293)" White oaksused asiCOuGrOl fo) =. ese te eee eee ee 6.41 56 8.73 
5294 | Serub pine treated with sulphur dioxid 1:10,000______________ 2.39 .48 20.08 
5295S CLUD PIE SCE iS COTE Oe ae ee 2.25 42 18.66 
5296 | Black oak treated with sulphur dioxid 1:50,000_______________ 3.64 .56 15.38 
520 fl: Black Oak USed aS iCONERO l= 22 ee ee ee ee 3.98 -50 1257 
5298 | Serub pine treated with sulphur dioxid 1:50,000______________ Ye ASA -47 18.72 
5299 | (Serubipine Used sas(COn Ci Ol2 == = eee ee 2.69 .30 13.01 
5300 | Serub pine treated with sulphur dioxid 1:100,000_____________ 1.96 43 21.94 
5301-1 Scrub pine used as COntEO)] an ee ee ee eee 2.05 ol 15242 
It will at once be seen from the foregoing table that all of the 
plants growing in the open which were treated with sulphur dioxid 
contained more sulphur trioxid in their leaves than the control plants, 
and that the percentage of sulphur trioxid in the ash of fumigated 
plants is higher than it is in those not fumigated. These results 
at once suggest a method for determining whether trees around a 
smelter were killed by the fumes or died from other causes. 
FIELD INVESTIGATIONS OF THE ACTION OF SULPHUR DIOXID 
FUMES ON VEGETATION. 
A CALIFORNIA SMELTER AND CERTAIN FOREIGN SMELTERS. 
The next step in the investigation was to determine whether the 
dead and badly injured trees around the smelting works near Red- 
ding, Cal., usually contained more sulphur trioxid than trees of 
the same species which stood close by in the same soil, but were not 
killed. Of 25 pairs of trees examined in various directions from the 
smelter 80 per cent contained more sulphur trioxid in the leaves 
of the injured trees than in the leaves of the uninjured ones, while 
20 per cent showed the reverse. It was further shown that in 80 
per cent of the cases the injured trees contained a larger percentage 
of sulphur trioxid in the ash of the leaves than did the uninjured 
trees.? 
7@U. 8. Dept. Agr., Bureau of Chemistry, Bul. 89. 
