546 PROCEEDINGS OP THE AMERICAN ACADEMY. 



The regular variation in members of the series C„H2a+2j appears in its 

 curve, and the differences in what are known to be isomeric forms in the 

 same series. It is further interesting to observe the continuation of the 

 curve representing the members of the series CnHgn from the curve con- 

 taining the members of the series C„Ho„ from California petroleum. The 

 lower values in the series CnH2n_2 from Texas petroleum form a char- 

 acteristic curve near the base of the table. 



The specific heat was determined in the following crude oils from 

 various fields : 



These values show that the specific heat of the crude oils is an im- 

 portant property from a practical point of view. It also appears that 

 there is no close agreement between specific heat and specific gravity. 

 Pennsylvania oil stands at the head, and Berea Grit with a much 

 larger proportion of volatile constituents is next. Of the heavier oils 

 it appears in general that the specific heats are much lower, but with 

 no definite relation. 



It would be interesting to ascertain the specific heats of the less 

 volatile constituents of petroleum from different fields, including the 

 solid hydrocarbons. This would require observations at different tem- 

 peratures, and it would add to the interest of the data if all determina- 

 tions could be made within a wide range of temperatures. 



Heats of Vaporization of Hydrocarbons of the Paraffine 



AND Methylene Series. 



Since it had been found that a boiling point constant can be calculated 

 from the absolute boiling point, and latent heat of evaporation, which 

 may be used as a basis of a method for the determination of molecular 

 weights, more complete knowledge of the latent heat of evaporation or 



