QUESTIONS 363 



from the jars they are handling. This residue, if the chemical 

 action has been complete, is not poisonous, but it is acid, and it is 

 always best to "keep on the safe side." It should therefore be 

 placed where it will do no harm. 



7. The lumps of cyanide, when placed in the bags, should be 

 approximately between two and four inches in diameter. 



8. If one must deal with returned sacks, they should be fumi- 

 gated before being placed in mill, as they are a prolific source of 

 infestation. 



9. Use four-gallon jars, never three or five, if it is avoidable. 

 Three-gallon crocks frequently boil over. 



10. For his own satisfaction in doing the work thoroughly, 

 and for the safety of his employees, no miller should undertake 

 this operation without having first become conversant with every 

 step of the process. 



11. Hydrocyanic acid gas penetrates readily through small 

 cracks and crevices. A mill in close juxtaposition with another 

 building not controlled by the miller, or within ten or twelve 

 feet of another building occupied during the process, would pre- 

 sent difficulties. 



12. Although this gas is not explosive at the strength above 

 recommended, it would appear to be a desirable precaution to 

 turn off lights and draw fires (if boiler or engine-room is included 

 or is reached by the gas) before the operation. 



13. In ordering material get more than enough, for if one 

 finds himself short at the last moment, and is at a distance from 

 the source of supplies, he certainly is in a predicament. Further, 

 order in time. Railroad companies will not ordinarily freight 

 acid in carboys with general merchandise ; they may hold the acid 

 several days or a week, waiting for an oil car. 



QUESTIONS 



1. Enumerate, in order of their importance, the insect pests frequently found 



in a flour mill and warehouse. 



2. Dp the same for those which are peculiar to granaries and elevators. 



3. Give description, life history, and habits of the Mediterranean flour moth. 



4. Describe in detail method of fumigation for mill pests with hydrocyanic 



acid gas. 



5. How would you proceed to eradicate the granary weevil from a bin or 



elevator? 



6. What methods should be employed by a housekeeper who finds her flour 



bin infested with the confused flour beetle? 



7. What pests mentioned in this chapter have you ever found in stored 



products? 



