104 C. M. Warren on the Volatile Hydrocarbons. 
Determinution of Vapor Density.— 
Temperature of balance, 16° 
Temperature of oil bath, 231° 
Height of barometer, 758°°4™™ at 14° 
Increment of balloon 0°4939 
Capacity of balloon, 221 ¢.¢. 
Density of vapor fo 281 
Excess found, 0253 
H,,, the calculation on the formula C, ,H,, does not show a 
reater variation from the density found, than we have observed 
to be quite frequent with hydrocarbons of so high boiling-point; 
so that it may be questionable which of these formule is the true 
one. I cannot regard the determination of a vapor density as 
reliable for fixing the formula nearer than to within two equiva- 
nts of hydrogen. In the absence of opposing evidence, it will 
the formula C,,H,,, which is also better supported by the re- 
Cahours,” by the dry distillation of a mixture of six parts 
crystallized cuminic acid, and twenty-four parts of caustic b 
Abel* obtained the same result by substituting caustic lime for 
the His product, however, was found to boil 4° above 
that of Gerhardt and Cahours. My preparation was also made 
by the use of lime. Although the results of my experiments 
confirm the conclusions arrived at by Gerhardt and Cahours as 
to the pee of this body, yet the numerical results differ 
considerab y from theirs, I have also observed some new facts 
regarding the formation of this body. They have described the 
* Annales de Chimie et de Ph ue, 1845, [3], iv, 87. 
* ‘Annalen der Chemie und Pharocie, 1847: lgiv bis 
2. CuMOLE.—This body was first obtained by Gerhardt and 
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