REPRESSION. 



163 



success. The method described below, from Farmers' Bulletin 209, 

 is that which has been used by the bureau in cases where it has been 

 necessary to free cotton seed of the weevils. 



The following plan for this work is proposed : A tight matched-board box should be 

 provided having sides 4 feet high, open on top, and of other dimensions to accommodate 

 12 or more 100-pound sacks of cotton seed placed upright upon the bottom. Another 

 tier of sacks could be added if desired. Into each one of these sacks about 1 ounce of 

 carbon bisulphid should be forced by an apparatus for volatilizing the liquid and mix- 

 ing the vapor with air. The accompanying illustration (fig. 34) will give an idea of 

 this apparatus. It should consist of three essential parts, as shown in the illustration. 

 A is an air pump having sufficient storage capacity to enable it to maintain a steady 

 discharge of air for several 

 minutes without continu- 

 ous pumping. The stop- 

 cock at a x regulates or 

 prevents the escape of air, 

 as may be desired. B is 

 an ordinary 2-quart bottle 

 fitted at b 1 with a tight 

 stopper of good length, 

 having two openings, 

 through which the inlet 

 and outlet pipes pass. 

 These pipes may be of 

 glass or metal and should 

 be as large as can be used. 

 The inlet pipe, 6 2 , reaches 

 nearly to the bottom of the 

 bottle and is provided at 

 the lower end with a per- 

 forated metal cap as large 

 as will pass through the 

 neck of the bottle. This 

 allows the escape of the 

 air in small bubbles and 

 insures rapid evaporation. 

 The outlet pipe, 6 4 , reaches 

 only through the stopper. 

 Upon the outside of the 

 bottle is pasted a paper 

 marked with 1-ounce grad- 

 uations. C is a piece of 

 ordinary f-inch iron gas 

 pipe about 3^ feet long, 

 but this may be any de- 

 sired length. It is closed 



and roundly pointed at the tip, and for about 15 to 18 inches of its length provided 

 with small perforations pointing in all directions to give free escape to the vapor into 

 all parts of the sack of seed at once. 



The connections may be of rubber tubing, but as little rubber as possible should be 

 used for this apparatus, as it is affected by the vapor of the bisulphid, and the couplings 

 will have to be frequently replaced. This, however, will not be a considerable item 

 of expense. With the apparatus just described one operator would be able to accom- 

 plish the entire work of disinfection. The amount of carbon bisulphid recommended 

 is about 1 ounce for each 3-bushel sack. It is safe to say that this can be secured for 

 less than 1 cent per ounce when purchased in 25 or 50 pound lots, making the cost of 

 bisulphid not over 1 cent per sack. As it requires but from two to three minutes to 

 vaporize 1 ounce of the liquid in the manner described, the expense for labor in appli- 

 cation would not amount to one-half a cent per sack. Fumigation with carbon bisul- 

 phid can therefore be effectively made at the slight expense of from 1 to 1^ cents per 

 100-pound sack. 



Application of the bisulphid in this manner reduces the elements of danger to a 

 minimum, as the vapor is almost wholly confined and the slight quantity escaping, 

 mixed with the open air, would not be in either inflammable or explosive proportions. 

 It has been determined that the slight trace of bisulphid vapor in the air would not 

 injure the operator in the slightest degree. The sacks should be left in the box for 

 forty hours after the gas is injected. 



bg^h/argec/ 



Fig. 34. 



-Apparatus for fumigating cotton seed in the sack. 

 Hunter.) 



(After 



