ADVERTISEMENT. 



jC{&t§ft\ R. Henckel's book on the Pyrites is in 

 ® D © the higheft efteem with all lovers of mine- 

 WfrW* ralogy -, both, on account of the fub- 

 jecTt ; a leading body in the mineral 

 kingdom, analyfed into its conftituent parts ; with 

 the ufe and importance of thefe parts at the fame 

 time fully difplayed : and on account of the method 

 of treating it *, as a pattern worthy of copying after 

 in our enquiries into nature, and ajuft fpecimen; 

 of the method of induction; 



Nor is the whole lefs inftructively interfperfed 

 with feveral fine and important obfervations in 

 mineralogy, chymiftry, affaying and fmelting, 



A tranflation, therefore, of fo ufeful a book, it 

 was hoped, would meet with a favourable reception 5 

 from thofe who are lovers of a folid knowledge 

 of nature, the genuine refult of obfervation and 

 experiment. 



Dr. Henckel, however, though in other refpedb 



fo excellent an author, is certainly but an indif- 



A 3 ferenj 



