148 RESEARCHES ON THE VOLATILE HYDROCARBONS. 



the assertion that no other body was present in appreciable quantity between the 

 temperatures mentioned. 



That this body from coal-tar naphtha, boiling at 140°, is not identical with cumole 

 from cuminic acid, will be made apparent on comparison of the results above stated, 

 with those which will be given when treating of cumole. 





4. Isocumole. ( Oymole of Mansfield.) 



Specific gravity, 0.8643 at 0°, and 0.853 at 15°. 



Determination of Boiling-point. — This was conducted with the usual precautions, and 



under conditions similar to those detailed above. The distillation, as in the foregoing 



determinations, was continued nearly to dryness, and occupied twenty-five minutes. 



Before distillation was commenced, the temperature of the boiling liquid was found to 



be 166°.5, and at the close of distillation 167°. Applying the customary corrections to 



the average of these observations, viz. 166°.75, we obtain for the corrected boiling- 

 point 169°.8. 





Analysis. — 0.1944 gramme of the substance gave, by combustion in a stream of 

 oxygen, 0.G366 of carbonic acid, and 0.1896 of water. 



Calculated. Found. 





Carbon, C 18 108 90.00 89.31 



Hydrogen, H J2 12 10.00 10.84 



120 100.00 100.15 



Determination of Vapor Density. — 



Temperature of balance, 

 Temperature of oil bath, 



13°.5 

 241°.0 



Height of barometer, .... 769.5 mm - at 9° 



Increment of balloon, 0.4206 



Capacity of balloon, .... 



239 c. c. 



Density of vapor found, . . . 4.3019 

 Theory C 18 H l2 , . . . 4.151 



Hence it appears that the calculated density on the formula C 18 H 12 is 0.151 less than 

 that found by experiment. The calculated density on the formula C^H^, which has 

 previously been assigned to this body, — although, as above stated, without an 

 analysis or determination of vapor density, — is 4.645 ; which is 0.302 greater than 

 that found by experiment. It will be observed that the difference between the den- 





