19 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 dioxrid, as shown by the sulphur trioxid determined in the foliage. 
[Calculated to dry basis.] 
Serial Ash in 
Sulphur trioxid— 
5 Description. dry == 3 = 
: leaves. |In 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 
52852 Mala cks Oa KAS eG eaSieO lites eee 3.68 259 16.03 
5284 | White oak treated with sulphur dioxid 1:1,000________________ | 6.49 2.01 30.97 
52856 | CW niteWak Usedcas COMET Ol: eae ee bee a oe eee eee | 5.94 57 9.59 
5286 | Cedar treated with sulphur dioxid 1:1,000________=_=_________ 5.46 .48 8.79 
HIS Cedar USedaas COM iLO leat a. suet eee rekaen es Bl ener warty See nges 6.06 .85 5.77 
5288 | Chestnut treated with sulphur dioxid 1:1,000_________________ 4.49 1.44 32.07 
Ssh) Gloag he wee Mi Comptolelo se Se 4.60 .06 N17, 
5290 | Black oak treated with sulphur dioxid 1:10,000_______________ 4.00 38) 18.25 
529s BlackiOaksusedsasiCOmbr Ol see ae te ee ae ee ane eee 5.09 56 10.09 
5292 | White oak treated with sulphur dioxid 1:10,000______________. a.02 .69 13.74 
SEB NAVI Ove! ON ero OL Beh COMM) Le oe 6.41 96 8.73 
5294 | Serub pine treated with sulphur dioxid 1:10,000______________ 2.39 48 20.08 
529 Al pS CLUDED IN EsUSEC aSiCOMtO) ae eee ee nee ne ee eee ee eee Bases 42 18.66 
5296 | Black oak treated with sulphur dioxid 1:50,000_______________ 3.64 .06 15.38 
D295 Alas lACK#IOAK USCA aSiCOMibhO) ease a 5 ne ee ee eee | 3.98 .00 LE 6 
5298 | Scrub pine treated with sulphur dioxid 1:50,000______________ 2.51 47 18.72 
SPATE ISO OH ON DNAS: WLC LEIS) COMMU EOE 3 ee ee 2.69 35 13.01 
5300 | Serub pine treated with sulphur dioxid 1:100,000_____________ 1.96 43 21.94 
HSOl ES LUD INE ISEC: aSiG OEY Oe =e ee ee = eee ee nee 2.05 31 1 hal2 
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.? 
2U. S. Dept. Agr., Bureau of Chemistry, Bul. 89. 
