FUMIGATION. 321 



plants can be placed for fumigation. If this is made to 

 contain ten cubic feet, about one dram of the cyanido 

 and one and one-half drams each of the sulphuric acid 

 and water will be required. 



For use in a greenhouse, it will be well to wet the 

 glass, so as to close as many of the cracks as possible. 

 Night should be selected, as the action of light and the 

 usual high temperature of the daytime will increase the 

 chance of injury to the plants, and lessen the injury to 

 insects. The plants should be on the dry side, and the 

 air moderately cool. At intervals of from thirty to 

 forty feet, place in the walk a tall two-gallon earthen jar. 

 Thus, for a house one hundred feet long, three jars will 

 be required, unless it is very narrow, or very wide, when 

 the number should be decreased or increased accordingly. 

 In each jar place a proportionate part of the water re- 

 quired for the house, and then carefully add an equal 

 amount of sulphuric acid. Care should be taken not to 

 allow any of the acid to come in contact with the cloth- 

 ing, or person, as it is very acrid and will destroy any- 

 thing that it touches. 



The amount of cyanide of potassium required for 

 each jar should be weighed out and placed in paper bags, 

 and just before it is to be used it should be placed inside 

 another larger bag, to prevent any danger of the bag 

 giving way while preparations are being made. Screw 

 eyos are then fastened in the woodwork directly over 

 each jar, and through these stout cords are run to the 

 end of the house near the door, where they are fastened. 

 To the ends over the jars tie the bags of cyanide, so 

 that, on the ends of the strings at the door being re- 

 leased, they will drop into the jars. When all is ready, 

 close the ventilators, pass to the end of the house and 

 carefully lower the bags into the jars and close the door. 

 If any of the cyanide drops into the acid while in the 

 house, hold the breath and get out of the house as soon 

 21 



