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EX PERI M EN TA I FA RMS 



2 GEORGE V., A. 1912 



constructed it will be necessary to double the quantities for each 100 cubic feet. The 

 most convenient method of generating gas is as follows : Supposing the chamber to be 

 fumigated is 20 feet long, by 20 feet broad and 10 feet high, the cubic capacity would 

 It 4,000 cubic feet. As each 100 cubic feet requires one ounce of potassium cyanide 

 and the remaining chemicals in equivalent proportion, we should require 40 ounces of 

 potassium cyanide, 40 ounces of commercial sulphuric acid and 80 fluid ounces of water 

 (4 pints). Two deep, fairly wide-mouthed earthenware vessels will be required. Into 

 each pour forty ounces of water and slowly add 20 ounces of the commercial sulphuric 

 acid. The potassium cyanide should be divided into two equal parts of 20 ounces each; 

 each part to be wrapped in thin paper. All is now ready for the generation of the gas, 

 if the chamber has been securely sealed. Stand each of the generating jars contain- 

 ing the dilute sulphuric acid on the floor on several sheets of paper to prevent any 

 injury should the acid splash over. As quickly as possible drop the cyanide tied 

 up in this paper into the jars; the one farthest from the door should be dropped 

 in first and the next immediately after so that the door may be reached before much of 

 the gas has been generated. The door should then be tightly closed and sealed for three 

 or four hours, or, if possible, overnight. The greatest care must be taken that no per- 

 son enters the room until it has been thoroughly ventilated after the fumigation is 

 complete. After fumigation the ventilators should be opened from the outside, as 

 provided and the room must be thoroughly ventilated for at least one hour before it is 

 entered. A single person should not carry on these fumigation operations or an 

 accident might prove fatal. 



It is not advisable to fumigate one room of a house only. The gas is lighter than 

 air and very permeable, in consequence of which it would penetrate other rooms and 

 have serious effects. It is always advisable to fumigate the whole house in case of 



Via. 2. Diagram illustrating method of stringing a room tor lumigatiun with hydrocyanic acid gas. 



serious infestations, beginning with the upper rooms, as the gas is light. Notices 

 should be given to those in adjoining houses and others who might be affected by the 

 gas, and a person should remain outside while the operation is being carried on. Too 

 many precautions cannot be taken in using a gas of the fatal and powerful nature of 

 hydrocyanic acid gas. 



