11 



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, J^, reaches nearly to the 

 bottom of the bottle and is provided at the lower end with a perforated 

 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 evapo- 

 ration. The outlet pipe, J*, 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 3i 

 feet long, but this may be any desired 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 accomplish 

 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 pur- 

 chased 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 application would not amount to one-half a cent per sack. 

 Fumigation with carbon bisulphid can therefore be effectively made 

 at the slight expense of from 1 to li 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. 



SUMMARY OF RESULTS OF FUMIGATION EXPERIMENTS. 



I. The fumigation of cotton seed in bulk offers many difficulties. The 

 adhering lint seems to form a dense mass very impervious to the com- 

 monly used fumigants. Moreover, the boll weevil seems unusually 

 resistant to these agents. 



II. At present it does not seem possible to use hydrocyanic acid gas. 

 Especially susceptible insects, like house flies, when protected by from 

 6 to 12 inches of seed, are not killed within five hours by a gas result- 

 ing from the use of 0.5 gram of potassium cyanide to the cubic foot. 



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