358 MILL AND ELEVATOR INSECTS 



Careful workmen then pour the right amount of water, six and 

 three-fourths pounds for every three pounds of cyanide, into each 

 jar. The acid should never be introduced first. Then, assuming 

 that a three-pound charge of cyanide is to be used in each case, 

 four and one-half pounds of the sulfuric acid is added to the 

 water in each jar. If acid is introduced first and then the water, 

 the jar is likely to crack. This must be done with care and every 

 precaution taken to keep all cyanide from proximity to the add. 

 The fumes arising when the acid is added to the water are in no 

 way dangerous. The next step is to carefully place each jar under 

 its proper package of cyanide, beginning at the top story and working 

 down. The bag should hang at least six inches above its jar, but 

 not so high that it will not reach the acid when lowered from the 

 outside of the building. The string used to suspend the bags 

 must be strong, and must have no weak places to invite accidents. 



Previous to this, or while it is being done, care should be taken 

 that every window is tightly closed, and it is assumed that all 

 cats which a miller may wish to save will have been previously 

 removed from the building. The ground floor being reached, and 

 all men accounted for, the doors of the mill should be closed, and 

 the charges on every floor, beginning with the top story, lowered, 

 by loosening the ropes connected with them and fastened outside. 

 Do not loosen any rope the freeing of which will open a window. 

 Further, if by chance any window has been overlooked, and is 

 found to be open after the men have left the mill, it is not safe to 

 let any one enter the building to correct the oversight. 



Should, by any chance, a bag fall into a " loaded " jar by the 

 breaking of a string, or through imperfect tying, the men working 

 on that floor should leave the floor instantly for the floor next 

 below, closing the door or opening through which they pass, and 

 they must not enter that floor again until it has been thoroughly 

 aired after treatment. 



Time Required. The charge is best set off at about 5 o'clock 

 P.M., and the mill left closed until 7 A.M. next day; guards should 

 be left about the building over night, and every necessary pre- 

 caution taken to guard against accident through carelessness or 

 ignorance. Do not fumigate if a strong wind is blowing; a per- 

 fectly still night is most desirable. 



After the Fumigation. At 6 or 7 the following morning open 

 all doors and windows possible from the outside. After two hours' 

 airing, the writer does not hesitate to enter any fumigated building. 



