BULLETIN 799. 



FORM IN WHICH CARBON DISULPHID IS SOLD AND WHAT IT 



COSTS. 



In small quantities carbon disulphid is put up in tight tin cans; in. 

 large quantities (50 to 1,000 pounds), in steel drums. It may be 

 purchased in small quantities from most druggists at from 25 to 35 

 cents per pound, but if any considerable quantity is to be used it is 

 better to buy from some wholesale druggist, or. better still, directly 

 from the manufacturers. Manufacturers can supply impure grades, 

 which are commonly used for insecticidal work, at a cost of from 10 

 to 15 cents per pound. The charge for steel drums is paid by the 

 purchaser, but the drums are returnable at purchase price. Ad- 

 dresses of manufacturers may be obtained from any entomologist or 

 from the director of any experiment station. 



PROPERTIES OF CARBON DISULPHID. 



LIQUID PROPERTIES. 



Liquid carbon disulphid is about one-fourth heavier than water. 

 It evaporates very rapidly upon exposure to the air, the rate of 

 evaporation depending largely upon the area of the exposed surface, 

 the temperature of the air and of the liquid, and the height of the 

 wall of the container above the surface of the liquid. Evaporation 

 may be retarded by mixing the liquid with various substances and 

 is almost wholly prevented by covering the surface with water, 

 which, being lighter, floats easily on top just as kerosene floats upon 

 water. The evaporation takes up heat in proportion to its rapidity 

 so that it may produce frost upon a hot day near the evaporation 

 surface. If the liquid is poured upon the hand or anywhere upon 

 the skin a burning sensation will be felt. This is due not to a burn- 

 ing but to a cooling process, as may be perceived readily by* touching 

 the spot with the other hand. No injurious effects result from get- 

 ting it upon the skin, although it takes out the moisture and oil, 

 leaving the skin dry and whitish. If confined on the skin, as under 

 a ring, it causes sharp, burning pain, and this doubtless is similar 

 to the sensation felt by animals when the liquid is poured into the 

 hair, Avhich serves to retard evaporation. 



The chemically pure liquid has a sharp taste and a rather SAveetish, 

 not unpleasant, odor Avhich is very similar to that of ether or chloro- 

 form. The j)ure chemical is completely volatile and will not injure 

 or stain the finest fabrics. It does not affect the edibility of food- 

 stuffs upon which it may be poured, and all trace of the odor disap- 

 pears quickly upon full and free exposure to the air. The ordinary 

 commercial article, however, has a decidedly yellowish color, due to 

 the excess of sulphur, and a decidedly unpleasant odor, due to the 

 hydrogen sulphid contained in it. The commercial article^ there- 



