APPENDIX. 
CHEMICAL EXPERIMENTS WITH CARBON BISULPHID. 
The chemical symbol of carbon bisulphid is CS,. Its molecules consist of one 
atom of carbon united with two atoms of sulphur. The specific gravity of the liquid 
is 1.29. The vapor is 2.63 times as heavy as atmospheric air. The pure article vola- 
tilizes rapidly and completely when exposed to the air. The liquid boils at 115° F. 
The vapor takes fire in air at about 300° F. and burns with a faint blue flame, with 
difficulty visible in daylight, but evolving considerable heat and decomposing the 
carbon bisulphid into carbon dioxide (CO,) and sulphur dioxide (SO,). The latteris 
the familiar gas given off by the burning of sulphur matches and is a strongly poison- 
ous suffocating gas, which should not be inhaled. Carbon bisulphid vapor mixed 
with three times its volume of oxygen, or an amount of air containing that amount 
of oxygen, forms a mixture which is very highly explosive upon ignition. As 21 per 
cent of the air is oxygen, one volume of liquid carbon bisulphid evaporated in 5,357 
volumes of air would form such a mixture. An atmosphere composed of one volume 
of carbon bisulphid vapor to approximately 14.3 volumes of air is liable to violent 
explosion in the presence of fire of any kind whatever, or a temperature of about 
300° F. without flame. We have here about the maximum danger point from 
explosion in the use of carbon bisulphid. 
At the suggestion of the writer, the Division of Entomology requested information 
from the Bureau of Chemistry of the Department of Agriculture on the following 
points: 
(1) Minimum proportional volume of carbon bisulphid vapor inflammable in air. 
(2) Minimum proportional volume producing an evident explosion. 
(3) Proportion producing most violent explosion and how violent. 
(4) Maximum proportional volume giving any explosion. 
(5) Temperature of ignition point. 
(6) Relative volume of vapor given by evaporation of one volume of liquid carbon 
bisulphid. 
(7) The proportion of vapor of carbon bisulphid in a saturated atmosphere. 
(8) The proportion of vapor produced in 1,000 cubic feet of air by the evaporation 
of 1 pound of carbon bisulphid. 
The following is abridged from the report prepared in response to this request in 
the Bureau of Chemistry by Mr. E. E. Ewell. 
AMOUNT OF CARBON BISULPHID IN A SATURATED ATMOSPHERE. 
Several factors affect this quantity, but the principal one is temperature. Begin- 
ning at the freezing temperature of water, 32° F., a series of calculations was made 
with increments of 9° F. in temperature. As will be seen by the accompanying 
table, the amount of carbon bisulphid taken up increases most rapidly as the highest 
temperature is approached. 
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