18 INJURY BY SMELTER WASTES. é ; 
In this table, with possibly two cr three exceptions, it will be 
noted that the soils close to the smelters contain very nearly the 
same amcunts 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 con- 
sidered 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 dam- 
‘age 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. 
~ Ina 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 per- 
centage 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 per- 
centage 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 per- 
centage 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 64 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 chem- 
ical analysis to be injured for at least 12 to 124 miles north of the 
smelters, 64 miles south, 54 to 6 miles east, and 94 miles west. 
