56 REPORT ON INJURIOUS INSECTS FOR 1907. 



APPENDIX A. 



INSTRUCTIONS FOR USING HYDROCYANIC ACID GAS. 



This, the most powerful and dangerous poison used in combating 

 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 tw r o 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, etc., proceed as follows : Add the 

 4 ozs. of sulphuric acid to the 7 ozs. of w r ater 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, butiit should be remembered 

 that it is unsafe to enter the house until an hour or more after the win- 

 dows and doors have been opened. The best results have been obtained 

 at a temperture of 50 F., about one hour after sunset, w r hen the 

 foliage is dry. 1 



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 Mr. G. F. Strawson informs me that he has obtained better results by pouring the diluted acid upon 

 the cyanide of potassum, 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. 



