ON CHLOROFORM. 
315 
Although rectified several times, the chloroform which 
had yielded this oil still retained the characteristic empy- 
reumatic odor. We therefore sought for some chemical 
reagent, which, without acting upon the chloroform itself, 
should either separate or destroy the oil it still contained. 
After some experiments, concentrated sulphuric acid ap- 
peared to us most suitable; it produced in the impure chlo- 
roform a brownish-red color, which was the more intense 
the more oil was contained in the mixture. This color, 
which it likewise produces in a far higher degree with the 
isolated oil, is due to its carbonization ; so that on distilling 
impure chloroform with a certain quantity of concentrated 
acid, we succeeded in obtaining a product which was no 
longer colored by this powerful reagent, and possessed no 
empyreumatic odor. 
We were then able to analyse the chloroform thus puri- 
fied, and to examine its properties compared with those of 
normal chloroform. Composition, boiling-point, density in 
the liquid state and in the state of vapor, were all found to 
be perfectly alike; and we were able to assure ourselves 
that there exists but one chloroform, and that that derived 
from wood-spirit does not differ in the least from the chloro- 
form from alcohol when the precaution has been taken to 
separate the whole of the oil above-mentioned. However 
it must be stated that the complete separation of this oil 
was not effected; there still remained a minute proportion, 
so small indeed as to have no influence either on the spe- 
cific gravity or on the results of the analysis; but it was 
evident, from the odor which remained after evaporating a 
sufficiently large quantity of chloroform; and likewise the 
vessel used to take the density of the vapor, still percepti- 
bly retained the peculiar odor of this chlorinated methylic 
oil. It is almost impossible to remove the last traces of it; 
they resist the action of concentrated sulphuric acid even 
after long-continued contact. 
