CHAPTER XIII 

 PRACTICAL HINTS TO NURSERYMEN 



T!HK amounts of chemicals necessary for a room 

 i 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 

 for 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 n^ 

 ounces (liquid measure) of water. 



As a rule, we discard any fraction less than a half. 

 In this case, therefore, we would use 5 ounces of 

 cyanide, 7^2 ounces of acid, and n ounces of water. 

 The cost of chemicals to fumigate this room, full of 

 trees, would be about 1 1 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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