AGRICULTURAL BULLETIN 
OF THK 
5TRAJT5 
AND 
FEDERATED MALAY STATE5. 
FEBRUARY, 1910. [Vol. IX 
ON THE EFFECT OF ARSENICAL AND SULPHUR FUMES 
ON VEGETATION, WITH PARTICULAR REFERENCE TO 
THE PARA RUBBER TREE (HEVEA BRASILIENSIS) 
AND RAMBONG (FICUS ELASTICA.) 
In 1906-07 the question of the supposed deleterious effect of the 
fumes from the Chinese furnaces, in which low grade tin ores con- 
taining varying percentages of mispickel (arsenical iron pyrites) 
were roasted, was acute in one or two planting districts in Selangor, 
in the Federated Malay States, and numerous complaints were rife as 
to the injurious effects of the fumes not only on the Para rubber tree 
but on other forest vegetation, particularly at a certain elevation or 
height of tree. 
In my agricultural-chemical report for 1906 (vide Agricultural 
Bulletin, S. S. and F. M. S., Vol. VI., No. 9 , of September, 1907), 
brief mention was made of experiments then in contemplation to 
ascertain whether the complaints with reference to the injurious effects 
of the fumes on the Para rubber trees and on Rambong were justified, 
and also to ascertain whether such effects, if any, should be attributed 
to the arsenical or to the sulphurous fumes from these furnaces, since 
both are produced. 
Method of Roasting. 
A brief description of the method used by the Chinese for 
roasting these ores might be of interest. 
The furnace consists of a low brick structure, with a fire at one 
end, the flames from which pass over the ore, which is laid on the bed 
of the furnace (a reverberatory furnace) and the fumes are carried 
from thence into a long stack at the other- end. The time occupied 
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