MIU<S AND OTHER BUILDINGS 173 



marked success. We allowed the gas to remain in the 

 building one night and day. The next morning we 

 found everything had perished, including many mice 

 and weevil. The last day or so we have noticed one 

 or two weevil, probably some that survived by being 

 deeply buried in cracks. We can certainly speak a 

 good word for the remedy, and thank you very much 

 for your instructions, which has aided us in free- 

 ing our mill and warehouse from such troublesome 

 pests. 



Repeated applications demonstrated that the remedy 

 is one that can be relied upon when properly used. 

 An occasional miller, however, may get a bad lot of 

 chemicals and can not generate the gas properly. One 

 of our Canadian friends wrote recently that he was not 

 very successful in his fumigation, stating that the 

 cyanide did not work in the acid and water. It was 

 apparent to me he had used an old grade of cyanide, 

 about 58 per cent, purity, where he should have had 

 the chemically pure cyanide, guaranteed 98 to 99 per 

 cent. My suspicions were well founded, and a few 

 days later, at my suggestion, he tried the pure cyanide 

 with good results and wrote me as follows August 15: 



Your letter of July 22 was duly received and care- 

 fully noted. About ten days ago we fumigated again 

 with the hydrocyanic acid gas, and this time with 

 complete success, hardly a bug or grub of any kind 

 being left alive. We see an odd one occasionally, both 

 moth and weevil, and we expecl; there will be some 

 hatched out from eggs left. We shall fumigate again 

 in another month or so if necessary. The fumigation 

 is so simply done, and so deadly, that we have now no 



