340 
SELECTED ARTICLES. 
ART. LX.— NOTE UPON THE DISTILLED OIL OF 
CAOUTCHOUC. By W. Gregory. 
This oil discovered by Mr. Enderby of London, possesses 
very remarkable properties. It is volatile, extremely fluid, 
and has an exceedingly low specific gravity. Of this oil I 
procured a certain quantity from Mr. Enderby, who stated 
that he had simply purified it by rectification. After having 
rectified it twice, without ebullition and so gradually as to 
pass over but two drops per minute, which was accomplished 
at a temperature between 25 and 30°, I ultimately obtained a 
liquid weighing 0.666 at 15°. Up to the present time, but 
one liquid having less specific gravity is known; this is the 
eupione of M. Reichenbach, the density of which is 0.655. 
But the oil of caoutchouc is not eupione, for it is acted upon 
and decomposed by sulphuric acid, while eupione when puri- 
fied by means of this acid is perfectly capable of resisting it. 
The odour of the oil of caoutchouc is peculiar and in a slight 
degree resembles that of eupione, it is however less agreeable 
and more ethereal. It has no fixed point of ebullition. That 
of 0.670 begins to boil at 35°, but the temperature soon be- 
comes higher, and at the termination of the distillation it has 
risen to 65°. This substance therefore cannot be regarded as 
pure and uncombined. 
I have however analyzed it, and the results of the analysis 
closely correspond to the formula CH2, that of olefiant gas. 
When sulphuric acid is added by little and little to the oil 
at the bottom of a long tube, taking care to close and refrige- 
rate the tube after each addition, a liquid is obtained which is 
supernatant upon a brown mass and equal in quantity to half 
the oil employed. This liquid, after being washed with water 
and potassa, was distilled, and furnished an oil having an aro- 
matic terebinthinate odour and boiling at 225°, or perhaps a 
little higher, a circumstance somewhat remarkable. The 
analysis of this new liquid still gave the formula CH2. 
These analyses have been made by M. Liebig, who direct- 
