CARBON BISULPHID AS AN INSECTICIDE. 
INTRODUCTION. 
Tt is the purpose to bring together in the following pages some of 
the principal facts concerning the use and effects of carbon bisulphid. 
During the years since it was first used as an insecticide many impor- 
tant facts have been established. Records of these facts are, however, 
so widely scattered that it has been difficult to bring enough of them 
together to obtain even a fair understanding of the nature and use of 
this substance. Moreover, many of the most important facts have 
been practically buried in the mass of French literature concerning the 
grape Phylloxera. The writer claims but little of this work as original; 
but many of the conclusions he has verified by his own experiments, 
and the data furnished by the Bureau of Chemistry are almost wholly 
new. The chemical side of the subject has been treated in an appendix, 
in order that those desiring to do so may easily inform themselves as 
to the properties and behavior of the liquid which they may handle. 
PROPERTIES OF CARBON BISULPHID. 
Carbon bisulphid is a colorless watery liquid, formed by the union 
of two elementary particles of sulphur with one of carbon (charcoal). 
Its chemical symbol is CS,. It is made on a large scale by passing 
the fumes of burning sulphur over red-hot charcoal. ‘The resulting 
vapors are condensed to a liquid form by cooling, and the impurities 
are removed therefrom. 
LIQUID PROPERTIES. 
The liquid is one-fourth heavier than water, its specific gravity 
being 1.29 at the freezing temperature of water. It is extremely 
refractive, so that when its surface is disturbed it reflects the light 
from the ripples much more strongly than does water. It is very vol- 
atile, evaporating with great rapidity when freely exposed to the air, 
The rapidity of evaporation depends mainly upon the area of the 
evaporating surface and the temperature of the liquid and the air. It 
may be retarded by mixing the liquid with various substances, and is 
wholly prevented by covering the surface of the carbon bisulphid 
with a layer of water, which, being lighter, floats easily on top just as 
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