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Insects in greenhouses which attack the leaves of plants, 

 and cio not live m the soil, fumigation v/ith hydroc}'anic 

 acid gas is the best general remedy. Ir is made up as 

 follows: — 2 ozs. cyanide of potassium, 4 ozs. sulphuric 

 acid, and 8 ozs. of water. iiLStimate cubic space of green- 

 house and use this preparation for each 1,000 cubic feet 

 of space, doubling the quantity for 2,000 cubic feet, and 

 so on. First close up all windows and doors and any 

 holes should be securely hlled up. One window should 

 alone be left open for purpose of introducing the mix- 

 ture, which is extremely poisonous to man and all forms 

 of animal life, but does not injure plants. Use at ditsk 

 when the plants are dry, and the temperature of the 

 greenhouse should not exceed 60 F . — the best temperature 

 IS 50 F. Do not use when there is a bright light 'clay- 

 light). Pour the water into a jar hrst, and then add the 

 acid slov%'ly. V\'rap the cyanide m a piece of blotting- 

 paper and drop into the jar with a suitable instrument 

 from outside through the window of the greenhouse. 

 Then close the window and leave for at least i hour. 

 Afterwards open all doors and windows from the outside, 

 but do not enter the greenhouse until another hour has 

 elapsed. Cost about 6d. 



