386 Proceedings of the Royal Society of Edinburgh. 



The author farther remarked, that rivers, estuaries, or portions 

 of the sea, now How through or cover strata of this coal formation, 

 which, from the appearances on their opposite shores, were in all pro- 

 bability once continuous. The connection between the Lothian coal- 

 fields and that of Fifeshire is very apparent, both in the general di- 

 rection of the strata, as seen by their outcrop on the opposite shores 

 of the Frith of Forth, and in the number and thickness of the beds 

 of coal in each, which exactly correspond. The appearance of the 

 carboniferous series in Arran, and at Campbelton in Kintyre, as well 

 as the indications of its existence at Ballycastle, and other places on 

 the Irish coast, within the prolongation of the lines before adverted 

 to, seems fully to establish the geological connection in this, as well 

 as in most other respects, between the west^of Scotland and the north- 

 east of Ireland. 



2. On the composition of the Rangoon Petroleum, with Re- 

 marks on the composition of Petroleum and Naphtha in ge- 

 neral. By William Gregory, M.D. F.R.S.E. 



The author first adverted to the discovery, nearly about the same 

 time, of paraffine by Reichenbach and of petroline by Dr Christison. 

 The former occurred among the products of destructive distillation ; 

 the latter was found in the Rangoon petroleum, and they were soon 

 found to be identical. Reichenbach's researches on naphtha were 

 then quoted, by which it appears that that indefatigable observer 

 could not discover, in the kind of naphtha which he examined, any 

 trace either of paraffine, or of any other product of destructive distil- 

 lation. On the contrary, he found that naphtha to possess the cha- 

 racters of oil of turpentine, a product of vegetable life j and he suc- 

 ceeded in obtaining a precisely similar oil from brown coal by distil- 

 lation at 212°. These facts had led Reichenbach to the conclusion 

 that naphtha in general is not a product of destructive distillation, 

 and, consequently, must have been separated at a comparatively low 

 temperature. The author showed that Dr Christison's discovery of 

 paraffine, of which Dr Reichenbach was necessarily ignorant, is in- 

 consistent with this view ; and detailed some experiments, by which 

 he has rendered highly probable the existence in petroleum of 

 eupion, another of the products of destructive distillation. This 

 substance is a liquid of Sp. gr. 0.655, boiling at 110°, and very frag- 

 rant. The author obtained from the Rangoon petroleum a liquid of 

 Sp. gr. 0.7-14, boiling at 180°, and rather fragrant. The oil of tur- 

 pentine, as is well known, boils at 280, and has a Sp. gr. of 0.860 ; so 

 that, at all events, the naphtha from the Rangoon petroleum is not 

 oil of turpentine. This was farther proved by the tests of nitric 

 acid and iodine. Similar experiments on one or two other species of 

 naphtha led to similai* results. They all yielded a liquid of Sp. gr. 

 about 760, and, consequently, could not be oil of turpentine. The 

 kinds of naphtha tried were Persian naphtha, obtained from Dr 

 Thomson, and commercial naphtha, sold by M. Robiquet of Paris. 



The author concluded, that if the naphtha examined by Reichen- 



