1 16 Two Expermients in House Fumigation 



Bisulphide : 1 lot of 4 lbs. ; 

 " 7 lots of 3 lbs. : 

 14 lots of 2 lbs. ; 

 1 lot of 1 lb. 



The bisulphide was apportioned according to the floors, landings and 

 staircases. The procedure was as follows ; a list was made of the rooms 

 and the special places requiring doses either of cyanide or bisulphide : 

 on this the quantities were estimated, the chemicals were obtained and 

 the owners went out. With the help of Messrs Davidson and Awati the 

 fumigation was done between 10.30 a.m. and 1 p.m. 



The acid and water was mixed in the yard in proper quantity for 

 each room in a jug or basin and put there ; the cyanide was weighed into 

 pieces of cloth about 20 inches square and placed beside each basin; 

 rooms were allotted and signals fixed : the bisulphide was then measured 

 into jugs and placed beside the cyanide. 



All being ready and the sequence of operations fixed for each floor, 

 we commenced at the top, each pouring his dose of bisulphide down the 

 floor and standing by with the cyanide : at the signal the cyanide was 

 dropped into the acid and each man bolted out: in this way the floors 

 were done : the most difficult was the ground floor, where there were 

 seyen charges of cyanide and nine of bisulphide to be let off by three men 

 but we emerged without mishap. 



The house had been prepared by closing all openings, opening out 

 cupboards, books, etc., and taking up all carpets; where possible a 

 plank was taken up in the floor. All fires were out, all chimneys closed, 

 all gas off. 



Success turned on penetration of the floors, which I hoped to secure 

 by pouring down bisulphide. The strengths were worked out at 1 lb. of 

 cyanide to 700 cubic feet and 1 lb. of bisulphide to 500 cubic feet, 

 assuming each to penetrate the whole house. The hydrocyanic prob- 

 ably never penetrated the floors and the bisulphide did not saturate 

 above floor level, so each was much stronger, certainly at first. 



The cost of chemicals was : 



40 lbs. cyanide 98 per cent, fused at Is. 2d. 

 40 lbs. sulphuric acid coml. at IM. 

 54 lbs. bisulphide at id. 



3 9 8 



The house was visited twenty-six hours after the fumigation and the 



