CHAPTER Xi 
PRACTICAL HINTS TO NURSERYMEN 
HE amounts of chemicals necessary for a room 
are estimated in terms of cyanide per cubic 
foot of space enclosed. For example, let us 
suppose a room contains 564 cubic feet. We 
use 0.25 (twenty-five hundredths) gramme of cyanide 
tor each cubic foot. We therefore multiply 564 by 
0.25. Thus, 564 X 0.25 = 141.00 grammes of cyanide. 
To reduce this to ounces we divided 141.00 by 28.35, 
as there are 28.35 grammes in an ounce. ‘Thus, 
141.00 + 28.35 = 5 ounces (a fraction less), the amount 
of cyanide needed for the house. ‘The other chemicals 
are easily determined, as a half more acid, liquid meas- 
ure, than cyanide, and a half more water than acid 
are used. ‘Thus, the room needs 5 ounces cyanide (by 
weight), 7% ounces acid (liquid measure), and 11% 
ounces (liquid measure) of water. 
Asa tule, we discard any fraction less than a half. 
In this case, therefore, we would use 5 ounces of 
cyanide, 7% ounces of acid, and 11 ounces of water. 
The cost of chemicals to fumigate this room, full of 
trees, would be about 11 cents. The amount of cya- 
nide needed for any room can be determined in the 
same manner. First, see to it that the cubic contents 
of the enclosure has been accurately computed, then 
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