SCIENTIFIC NEWS. goy 



process no inflammable gas is given out; but at a high 

 temperature the oil is more or less decomposed, and in- 

 flammable gas is produced ; winch, however, does not burn 

 with a flame by any means so bright as the gas ironi pit 

 ccaL 



If this destructive distillation is not earned very far, „ ., 



J Residuum, 



the matter in the retort will be found, when cold, to be 



solid, brilliant, shining, and possessed of a conchoidat 



fracture: its taste is bum ng and pungent, and its odour is 



that of wood smoke. It is fusible and readily inflammable. - 



When kept melted in an open vessel, till it ceases to be 



fusible, it becomes more and more brilliant, its fracture 



passes to splintery, and it assumes the perfect appearance 



of asphaltum. In proportion as it approaches-this state it 



becomes less and less soluble in alcohol, and at length 



scarcely gives a stain to this mentruum. Naphtha has no 



action on it, and in this circumstance alone it differs from 



asphaltum. 



Dr. Mac Culloch then proceeds to an examination of the Difference be- 

 bitumens, and shows, that the difference between the pro- tw en bitu- 

 ducts of recent vegetable matter and of the bitumens, when cen . yegetable 

 subjected to distillation, consists in the former yielding matter, 

 empyreumatic acetic acid, and a black pitchy matter in- 

 soluble in naphtha ; while the latter afford ammonia and 

 naphtha, but little or no acid. 



He then enters into a detailed investigation of the pro- Lignites ex- 

 perties of the very important class of lignites, or those ainined. 

 substances such as peat, surturbrand, Bovey coal, &c. in 

 which the traces of vegetable origin a«-e not obliterated. 

 Submerged wood from peat mosses gave a brown oil, 

 smelling of wood tar, and refusing to dissolve in naphtha. 

 A compact pitchy looking peat gave a fetid oil, resembling 

 in odour neither wood tar nor bitumen, and very slightly 

 soluble in naphtha. Bovey brown coal gave an oil resem- 

 bling in odour that of wood tar, but much more soluble in 

 naphtha. That portion of the oil which was insoluble in 

 this menstruum had a strong odour of wood smoke. The 

 oil of jet was almost juy^fectly soluble in naphtha, and 

 3melled strongly of pidMTcuro, but it afforded also empy- 

 jreumatic acetic acid. 



Thus 



