322 Dr. W. Gregory 07i a volatile Liquid 



decomposed by oil of vitriol ; while eupion boils at 1 10° Fahr., 



and resists the action of that acid. 



The boihng-point of the new oil is not constant. That of 

 sp. gr. 0-670 begins to boil at 95° Fahr., but the tempera- 

 ture soon rises, and towards the end of the distillation reaches 

 1 70^ Fahr. Consequently, we cannot consider it as an un- 

 mixed compound. 



Having taken some of this liquid with me to Giessen last 

 year, I submitted it to analysis under the eye of Professor 

 Liebig. Although I did not expect any very satisfactory' result 

 from the analysis of a substance confessedly not free from mix- 

 ture, I was rather surprised to obtain results indicating a com- 

 position, in 100 parts, identical with that cf olefiant gas. 



I next proceeded to examine the action of sulphuric acid 

 on the new lic|uid. When the acid is added to it in large 

 quantity, part of the oil is decomposed instantaneously, while 

 the rest is dissipated by the heat evolved, leaving a black 

 semifluid mass. But if the acid be added gradually to the 

 oil at the bottom of a long tube, which is closed by the thum.b 

 and cooled dovvn after each addition, a colourless liquid is 

 obtained, swimming on the surface of the black mass above 

 mentioned. When the addition of new acid causes no further 

 development of heat, the liquid may be decanted, washed with 

 solution of potash, and rectified over chloride of calcium. 



This liquid has properties very distinct from those of the 

 oil which has yielded it. It has acquired an aromatic smell, 

 resembling that of turpentine, and it now boils at about 440° 

 Fahr. Notwithstanding, however, this remarkable change, 

 the analysis of the modified oil gave results closely coinciding 

 with those of the original liquid, viz. a composition identical, 

 in 100 parts, with that of olefiant gas. 



These analyses were made in September 1835. In the 

 Annalen tier Pharmacie, October 1835, Professor Liebig has 

 directed the attention of chemists to the remarkable alteration 

 produced by sulphuric acid on the oil of caoutchouc; and has 

 conjectured that the change consisted in the conversion of 

 that oil into eupion, which resists sulphuric acid. If so, he 

 proceeds, then it is possible that eupion may be only pro- 

 duced from the oil of tar by the action of the sulphuric acid 

 employed in its preparation. 



I cannot acquiesce in this view. The eupion of Reichen- 

 bach boils at 110° Fahr., and the oil alluded to at 440° Fahr.; 

 moreover their odour is quite different : and if we are to ad- 

 mit them to be essentially the same, one of them must be in 

 the highest degree impure, implying the presence of some 

 other substance. 



