RESEARCHES ON THE VOLATILE HYDROCARBONS. 139 



identical with the hydrocarbon existing in oil of cumin. It thus appears that of the 

 four bodies which Mansfield detected in coal-tar naphtha, benzole is the only one 

 which he had studied in any detail. Indeed he distinctly states that the others had 

 not yet been isolated in such a state of purity as to entitle them to analysis. And 

 yet his conjectures as to the identity of these bodies, thrown out by way of prelimi- 

 nary notice of results which were acknowledged to be incomplete and inaccurate, have 

 nevertheless been extensively quoted, and generally received as established facts. 

 In addition to the bodies already mentioned, Mansfield also detected the presence of 



a body more volatile than benzole, having an alliaceous odor, which he found to boil 

 between 60° and 70°. Ritthausen* made a re-examination of the light coal-tar naph- 

 tha, in order to obtain the hydrocarbons in a state of greater purity, and to prove the 

 correctness of Mansfield's view of the composition of this naphtha. In regard to the 

 results which he obtained, he says they fully confirm those of Mansfield. Of the 

 body which Mansfield designated as probably identical with cymole, and of the oil 

 more volatile than benzole, Ritthausen obtained quantities too small to admit of 

 investigation. In regard to the latter, however, he remarks/)* that to Mansfield's 

 account he can add, that * its nitro-product quite resembles that of benzole, and hence 

 that at all events it belongs to the series C n H n _ 6 , and perhaps has the formula 

 Cio H 4 ." J It is to be regretted that Ritthausen also omitted to analyze and determine 

 the vapor density of any one of these substances, he having added, therefore, nothing 

 more than a confirmation of the results of Mansfield. He gives the boiling-point of 

 benzole at 80°, of toluole at 109°, and of the so-called cumole at 139-140°, which will 

 be found to agree very nearly with my own determinations. Church, § in the follow- 

 ing year, published a paper on the " Determination of Boiling-points " in the " Ben- 



* 



t 



LXI 



on 



tiber das letztere nur das hinzufugen, das seine Nitroproducte 



an 



Q» 



X 



body 



and indeed in considering it as a hydrocarbon at all He was evidentl; 

 containing benzole. Furthermore, as Mansfield suggested might be po 



mixture 



had a large quantity of this 



^parate 



great 



constant at about 40 



pounds containing sulphur, and therefore will more properly form the subject of a separate 



paper. 



§ Philosophical Magazine, 1855, 4th Series, IX- 256 



* 



