62 REPORT ON INJURIOUS INSECTS FOR 1904. 



APPENDIX A. 



INSTRUCTIONS FOR USING HYDROCYANIC ACID GAS. 



This, the most powerful and dangerous poison used in com- 

 bating insect pests, should on no account be used by uninstructed 

 or careless people. 



The materials required are a 2 Ib. pot jam-jar, in which place 

 7 ozs. of water, to which add 4 ozs. of sulphuric acid ; and, as 

 directed below, 2 ozs. of 98 per cent, cyanide of potassium for 

 every 1,000 cubic feet of space. 



First make the room to be fumigated as air-tight as possible, 

 leaving one window to open from the outside. Then wrap up 

 the pieces of cyanide in blotting-paper. Having placed in the 

 jam-jar the water and acid, place the jar just within the room 

 to be fumigated, draw the door nearly to, and with the arm reach 

 in and drop the wrapped-up cyanide into the jar, and close the 

 door immediately. Strips of paper well sized should then at 

 once be placed over the crevices. 



The room should remain closed for from two to three hours ; 

 then open the window from the outside, and leave until thoroughly 

 well ventilated. Remember the fumes and the cyanide are 

 deadly poison. Care should be taken that no one remains 

 outside the door of the room as in a passage, as some of the 

 fumes might escape. 



In conservatories, greenhouses, &c., proceed as follows : 

 Add the 4 ozs. of sulphuric acid to the 7 ozs. of water in a jar ; 

 then take the cyanide, which should be wrapped up in blotting 

 paper, and by means of a stick or piece of string drop it into the 

 water from the outside of the greenhouse. The window or door 

 should then be shut, and the house should remain closed for 

 three-quarters of an hour at least, after which time they can be 

 opened to ventilate, but it should be remembered that it is unsafe 

 to enter the house until an hour or more after the windows and 

 doors have been opened. The best results have been obtained 

 at a temperature of 50 F., about one hour after sunset, when the 

 foliage is dry. (i) 



INSTRUCTIONS FOR USING BISULPHIDE OF CARBON. 



The fumes of this chemical, in addition to being deadly 

 poison to all animal life are also highly inflammable. No light, 

 such for instance, as a lighted cigar or pipe should be brought 

 near it, nor should it be used where there are electric wires. 



i Since the above was written Mr. G. F. Strawson informs me that he has obtained better results by 

 pouring the diluted acid upon the cyanide of potassium, using no blotting paper. He has also 

 devised and successfully used in conservatories &c., a series of fans, consisting of boards suspended 

 by two cords with a string at each side. The strings to the right and left are worked through a hole 

 in the doors, or other woodwork. 



