113 



TAB. CCCLXI. 



HYDROGEN Bitumen. 

 Inspissated Bitumen, or Mi?ieral Tar, 



Class I. Combustibles. Order 1. Simple. 

 Gen. 1. Hydrogen. <S^ec. 2. Bitumen. 



Syn. Mountain or Mineral Tar. Hatchett in Linn, 

 Trans. 4. 131. 



1 his variety represents Tar so much as to be well entitled 

 to the appellation of Mineral Tar. Naphtha and Petroleum 

 lead equally to this and to the soft elastic Bitumens, branch- 

 ing off on one side to the elastic and on the other side to 

 the unelastic, of which this specimen is one. It is inflam- 

 mable, and in other respects, as to odour, &c, it is like 

 the others. It is found, apparently in the greatest abundance, 

 in the neighbourhood of Dumbarton, whence the present 

 specimen : it is otherwise very rare. It is remarkable that 

 the Iron-stones (Septaria) are the chief deposit of it. The 

 present specimen is part of one, and I have a Coal Septa- 

 rium not much unlike tab. 61, upper figure, that has this 

 soft substance in it. I have also a specimen among Quartz 

 and Yellow Copper Ore from Carrharac in Cornwall, with 

 some in a more brittle state, so as to take the impression of 

 the finger nail, but partly breaking at the same time with a 

 bright pitchy fracture. I have some also in Copper Ore 

 from Lancashire that unites the two; it is accompanied with 

 dark Limestone. 



VOL. IV. K 



