i 
and a decreasing amount on each of the succeeding floors, maintain- 
ing the total proportion for the building, however, at approximately 
10 ounces of cyanid to 1,000 cubic feet of space. An estimate of this 
kind is illustrated by the second table. 
Assuming that the capacity of the upper floor of a given building 
is 96,000 cubic feet, the minimum amounts of each reagent and water 
required, according to the same formula, would be: 
Gye Gis POTASH 22s sa. 25 Se eas Se Bl ot ge 60 pounds avoirdupois. 
PLD MUG HCIOh riage nossa ene soe oar wees 3 60 pints. 
Waterss 022- BEES AES Sg eee ae 180 pints. 
This would necessitate the use of twenty 3-gallon generators and 
would naturally require the same number of bags which would con- 
tain 3 pounds eaeh of the cyanid salt. 
While it is essential to success that the cubie contents of each floor 
be accurately computed, it can be readily seen from the foregoing 
that many of the details as to the strength must be left to the judg- 
ment of the operator, since we have reports of nonsuccess or of only 
partial success where greater strengths have been used. As fre- 
quently happens these reports emanate from distant sources and it 
has not been possible to give them personal investigation.“ 
Whenever a building can not be so tightly closed asin the case last 
mentioned—and this matter must necessarily be left to the judg- 
ment of the operator—additional quantities are necessary. This is 
accomplished by employing, for each 1,000 cubic feet, one-fourth to 
one-half more or even twice the quantity of each ingredient. The 
amounts to be used for other still more loosely constructed buildings 
can be calculated in the same manner. 
The following tabular statements are submitted as aids in com- 
puting the exact proportions for hypothetical buildings of about 1,000 
barrels (daily) capacity.? 
The amounts of chemicals to be used for a given building or other 
inclosure are in direct proportion to the degree of tightness to which 
it may be closed. Owing to the great variability of buildings and 
parts thereof as regards tightness, it follows that no uniform strength 
can be prescribed. 
a Asan example, a Wisconsin miller wrote in June, 1909, that, although he had used 
hydrocyanic-acid gas at the rate of 2 ounces of cyanid to each 100 cubic feet of space 
(20 ounces to 1,000 cubic feet) for 36 hours, a few individuals seemed to have been 
missed although everything within reach of the gas was positively killed. This led 
to the conclusion, in which most millers of experience concur, that the eggs are seldom 
killed by this or other methods of fumigation now in use. Professor Washburn, how- 
ever, has succeeded in destroying them, and we fumigated last year (June 6, 1909) a 
mill product in which there were eggs of this species which later failed to develop. 
b It should be here stated that millers generally are very apt to take the outside 
measurements of a building instead of the inside and do not always calculate with 
sufficient care the height of each floor. 
eins 102) 
