Nov. 2, 1920.] 



Agricultural Gazette of N.S.W. 



821 



Potassium Cyanide for Trapping 



Fruit-flies^ 



A. A. RAMSAY, Principal Assistant Chemist. 



At the last conference of the field staff of the Fruit Branch of the Depart- 

 ment of Agriculture, attention was drawn by one of the field officers to the 

 successful use of weak solutions of potassium cyanide as a bait to trap fruit- 

 flies, and a recommendation was made that investigations be carried out to 

 ascertain the rate of alteration or decomposition occurring in potassium 

 cyanide solutions when so used. 



l/'Oeys I 



t3 



N'Days I 2 3 4 5 6 T B 9 10 ii 12/3/4 



Graph showing Rate of Decomposition in solutions of Potassium Cyanide: 



The experiments were designed as follows : — 



1. Aqueous solutions, containing ^ and 1 per cent, respectively of potassium 

 cyanide were made up, and the amount of cyanide present was determined. 

 These solutions were kept in a cool cellar, and the amount of cyanide 

 present was determined from day to day. 



2. Aqueous solutions containing | and 1 per cent, respectively of potassium 

 cyanide were prepared and treated as above described, except that the 

 solutions were kept in the open freely exposed to sunlight, and as nearly 

 under field conditions as possible. 



