244 



THE MONTHLY BULLETIN. 



bleached surface, and the clear white appearance of sulphur dioxide 

 injury is absent. 



Another form of injury sometimes mistaken for smelter fumes in 

 regions where smelters are operating, but not confined to such regions, is 



Fig. 47. — Oak leaves injured by sulphur dioxide 

 gas liberated in the smelting of ores. (Original.) 



a yellow condition of grains, supposed to be brought about by frost and 

 wet weather and possibly other factors as well. This condition is often 

 observed after excessive rains which may or may not have been followed 



Fig. 48. — ^Ijive oak leaves injured by sulphur 

 dio.xide gas liberated in the smelting of ores. 

 (Original.) 



by frost. To one who has become familiar with typical sulphur dioxide 

 gas injury, and wlio can distinguish between white ami yellow, there 

 should he no ecmfusing of the two ti'()iil)Ies. 



