t 
TOBACCO CULTURE IN THE WEST INDIES 29 
sary element because more of it was found in the leaf than 
of the other elements, but the statements made regarding 
the amount of potash actually necessary and the most de- 
sirable form in which to apply it were often misleading 
because the influence of potash was not fully known. It 
has been claimed by some that silicate of potash was the 
most desirable form and by others that carbonate of potash 
was the only real desirable form which claims have not been 
substantiated by later experiments. 
To settle these points a series of extensive experiments 
were inaugurated by the German Agricultural Society un- 
der the direction of Prof. Dr. Wagner and the results 
appear in bulletin No. 138 of that Society. 
NITROGEN 
In regard to nitrogen Prof. Wagner tried all of the 
different forms, nitrate of soda, sulphate of ammonia, ni- 
trate of ammonia, nitrate of lime and others. He found 
that nitrate of soda was not desirable which agrees with 
results obtained by others, the exact reason for this does 
not seem to be known but it is generally thought that the 
soda is detrimental to the burning quality. The influence 
of nitrate of lime has not been fully established but the 
actions of sulphate of ammonia and nitrate of ammonia 
were carefully compared by Prof. Wagner and he found 
in smoking tests that tobacco fertilized with sulphate of 
ammonia burned seven seconds longer than that fertilized 
with nitrate of ammonia, and he concludes that for the 
present at least it is safest to use sulphate of ammonia. 
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