4 
placing- the same ainoimt of acid and water in each crock as would be 
used if the potash were employed. In other words, for each jar figure 
2^/2 lbs. avoirdupois of cyanide of sodium, 4^ lbs. avoirdupois of 
acid and 6^ lbs. (or practically fij/d cpiarts ) of water. 
This circular is a consolidation of all ])revious circulars upon this 
subject with additional information gleaned from results of later work. 
No process is absolutely perfect, and millers should not expect neces- 
sarily, particularly in the case of badly infested mills, absolute immu- 
nity after the first and only treatment. The inexpensiveness of the 
process, and the fact that the gas at the strength used is non-explosive, 
and the further fact that it in no way injures dry mill products, makes 
it by far the most elifective remedy available. Its poisonous qualities, 
of themselves, make it safe in the hands of those accpiainted with it, 
for the knowledge of the possibly fatal results from careless manipula- 
tion insures extreme care in its use. Under such conditions it is to l)e 
regarded as a safe agent, but it should be borne in mind, not only that 
the cyanide of itself is poisonous, but also that one good whifi* of the 
gas engendered l)y the contact of acid and cyanide might produce fatal 
results. Drinking water or moist food of any kind should not be 
exposed to the fumes. Ilright steel may be slightly tarnished if not 
protected. 
Summing up the advantages of the hydrocyanic acid gas treatment 
it may be said : 
1. It is always availaljle and not expensive. 
2. It is a method of relief for mills outside of the “freezing" zone, and 
freezing is hy no means an ahsolnte cure. 
3. Its use at the strength indicated is absolutely safe as regards fire or 
explosiveness. 
4. It is absolute death, at strength used, to eggs as well as tlie other stages 
in the life of the flour moth. 
5. Rats and mice perish if they come in contact with the fumes. 
6. Its deadly qualities of themselves call for such extreme care in its use 
as to insure safety. In other words, in the hands of those acquainted with its 
nature and its use, it is a safe agent. 
The Method Briefly Described : 
Certain conditions are necessary to insure successful fumigation. In the 
first place the environment of the building to l)e treated is of importance. Mani- 
festly, if it is one of a l)lock of buildings, or if there is another building owned by 
a different party directly contiguous, in either of which cases the gas might 
penetrate where it is not desired, the permission of the owner of such property 
should be ol)tained. and precautions taken to prevent accident. W hen a mill 
stands hy itself at a distance from other buildings with which it is in no way 
connected, no such preliminary precautions are necessary. 
