Circular 21 - Inseotioides and Subsidiary Materials 14 
fermentation of liquors or by the combustion 
and decomposition of organic substances. The 
liquid when cooled forms a solid called "dry 
ice" which vaporizes without melting (at 
ordinary pressures) and is used as a refrigeimt. 
Liquid carbon dioxide is sold in 20 to 
25 pound cylinders at 6 to 8 cents per pound. 
Dry ice is also sold in 50-pound blocks. 
Available on contract: See Class 51, 
General Schedule of Supplies, Procurement 
Division, Treasury Department.. 
CARBON DISULFIDE 
The commercial grade of carbon disul ide, 
also called carbon bisulfide, is used to des roy 
ants by pouring a small quantity into the opeoi- 
ing of the nests. It has been used in the past 
in the fumif,ation of grains, cereals, and other 
comiaodities but, owin,'-^ to its inflammability, 
it is no\<i used to a lesser de,^;:ree and often in 
combination with carbon tetrachloride to reduce 
the fire hazard. It is also used as a fumlgant 
to aelouse clothing, and to control horse bot 
larvae. 
Chemically, carbon disulfide (CSg) is a 
heavy, colorless, or faintly yellowish liquid 
which boils at 115° F. It has a disagreeable 
odor and is quite volatile. The vapors are 
poisonous and very explosive when mixed with 
air in certain proportions. It will sometimes 
ignite from contact with hot steam pipes. It 
is only slightly soluble in water, but is a 
good solvent for many substances, including 
rubber, gums, waxes, varnishes, and oils. 
