of the Pyrites, 263 



ter, as by a kind of extraction, there mull be a 

 weathering or refolution to precede the flooding and 

 extraction. Yet, amidft all our uncertainty about 

 this matter, we obierve lime-done to be fubject to 

 dedruction and refolution, from which come highly 

 fubtile earths, which, as here, may change to a 

 formal done, and in other circumdances, to differ- 

 ent other productions. 



The nature of 'quartz, or flint-done, feems entirely 

 impregnable and lading -, yet thofe drufe and quartz, 

 which appear, as if gnawed and nibbled by mice, 

 feem to admit our calling their indedructibility in 

 queflion : and, I mud own, this fort of done may 

 contribute fomething to the production of ores, as 

 it is fo eminently adapted for that ground-earth, 

 called the dony and vitrefcible, by Becher. 



(2.) In the depths of the earth we have collec- 

 tions of flimy, fulphureous, and faline waters, 

 whence damps, vapours, and exhalations may arife, 

 which may greatly contribute to the production of 

 ores i from an internal incalefcence and fermenta- 

 tion, as it were, thefe matters exhale, and in con- 

 junction with other vapours, become proximately 

 adapted for the generation of all manner of mi- 

 nerals. 



(3.) Ores themfelves exhale, of which we have 

 palpable indances, tho' my experience extends only 

 to four forts, which exhibit any fuch change on the 

 furface of the earth. 



But this is not required of all; feeing (1.) feveral 

 forts of ores may be produced, tho* not feveral bo- 

 dies, weathered or refolved for the purpofe : as the 

 refolution of a red-goldijh ore is not requifn;e to the 

 production of an ore of that fort, but a quite dif- 



S 4 ferenc 



