Mr. Hatchett'j Obfervaliom on Biiumiwus Sub/lances. 145 



*5- 





LITTLE need be faid concerning thofe mixtures of bitumen 

 with metals or their oxides which are fometimes called the bitumi- 

 nous ores of mercury, copper and iron, for they fhould rather be 

 arranged with the adulterated or impure bitumens. Few of them 

 contain the metallic ingredient in a proportion fumcient to caufe 

 the compound to be worked as an ore ; and the only exception with 

 which I am acquainted, is the fubftance found atldria, in Carniola, 

 compofed of mercury mixed with bituminous matter, a quintal 

 of which, according to Mr. de Born, affords from fifteen to twenty 

 pounds of mercury *. 



§ 6. 



FROM the preceding obfervations it will appear, that although I 

 have nrft mentioned naptha in order that I might be better un- 

 derftood in refpea to the degree of conneaion prevailing between 

 the bituminous fubftances, yet, to have followed them from their 

 origin and the period of their formation, I mould rather have begun 

 with thofe fubftances which moft clearly point out how. much 

 the vegetable kingdom has contributed to the production of them, 

 with the probable occafional concurrence of animal fubftances. 



That the latter have contributed in fome meafure to the forming 

 of bitumen, we can only infer from the veftiges and exuviaj of 

 animals, which (o commonly accompany bituminous fubftances ; 



ppiertorf durchden moor odcr fumpftorf in den pechtorf, und von diefcm in die 

 feraun fchiefer und pechkohle.— JVidenmann^ p. 630. 



* Catalogue de la Colkahn des FeJJlIes. de M«'> de Raab t torn. ii. p. 2^4, 348, fc 400. 



Vol, IV. U but 



