OF FOSSILS. 



} CLVIII. Species oftbc Diamond. 



WE are acquainted with many differences of 

 the diamond, but with hone that are fpecific. 



J CLIX. Species of Sulpbur. 



THE fpocics of fuiphur are diflinguiflied by 

 the diveriity of their acids, and we know ot two 

 only ; the common farmed by the vitriolic acid, 

 and plumbago, containing the aerial acid iutura- 

 fed with phlogiilun. 



5 CLX. Species of Petroleum. 



THE varieties of petroleum, in colour and te^. 

 nuity, depend for the moft part on the degree 

 of exiiccation, and on the matrix or heteroge- 

 neous fubftanccs mechanically mixed with it; fo 

 that they can be confidercd but fcldom as fpe- 

 cilic. Exficcation produces a mafs thick and 

 tough, or folid and dry. 



CLX I. timber. 



THE fame obfcrvations nearly will apply to 

 amber. In refpeft of tranfparency and colour, 

 we meet with many varieties in the European 

 ipecies. 



Tte 



