RESEARCHES ON THE VOLATILE HYDROCARBONS. 11 



tion of any constituent which might be present in small proportion. The procese of 

 fractioning was continued on this large scale until the separations had so far pro- 

 gressed, that at certain temperatures a full barrel of distillate would come off from 

 the ten-barrel still employed, without a variation of more than one or two degrees of 

 the thermometer. Finally a sample gallon was taken from each of the barrels com- 

 posing the last series of products, and these samples were set aside for this investiga- 

 tion, which was afterwards conducted in the laboratory. 



Of the Results of Fractional Condensation. — Such of the samples above mentioned as 



* 



promised to yield the different constituents of the naphtha in the largest proportion, 

 were subjected to repeated series of fractionings by my process of " Fractional Con- 

 densation."* As full details of this process have already been given in the memoir 

 referred to, it will be needless to repeat them here. It will suffice to say that the 

 fractioning in this case was conducted in all respects as there described, and continued 

 until the whole of the naphtha taken, boiling between 80° and 170°, had accumulated 

 at the four points already indicated, viz. at 80°, 110°, 140°, and 170°; or so nearly the 

 whole that the intermediate quantities had become too small to admit of being 

 further operated upon. Having therefore so thoroughly exhausted the intermediate 

 fractions, I can have no hesitation in asserting that no other body than those alluded 



present in tne naphth 



ppreciable quantity, — hence, that the 



parabenzole of Church was probably only a mixture of benzole and toluole. I may 

 here remark that each of the sample-gallons employed, when subjected to my process 

 of fractioning, was found to contain, in variable proportion, all of the constituents of 

 the naphtha. 



i 



Of some of the Properties of the Bodies obtained by Fractioning. 



1. Benzole. 



Specific gravity, 0.8957 at 0°, and 0.882 at 15 e .5.f 



Determination of BoiUng-foint . — This experiment was conducted in a tubulated retort, 

 operating on 150-200e. c. of the benzole, containing some pieces of sodium. The ben- 

 zole employed had previously been repeatedly boiled with sodium, until the latter 



Memoirs 



t 



I .it wouia appear that the specific gravities ot liquids arc usu»ujr »»>»«"«• — — — r 



The result of this is that the determinations made by different observers are not comparable with one another. 

 That these specific gravities are not uniformly taken at 0° C. — the temperature which, on account of greater 

 convenience, etc. is generally acknowledged to be preferable — is probably due to the fact that the more 





