In the Pyrites. 225 



expofed to the air, but properly both together, 

 unlefs you would have a coaly or externally inflam- 

 mable fort. Air and fire are here to be confidered 

 not only in their inftrumentaU but alfo in their ma- 

 terial capacity ; or if they mud be called inftru- 

 ments, immanent: rather than tranfient. 



The air chiefly manifefls its virtue on, and in- 

 greis into the bodies of plants and animals, as in 

 good part not only being derived from it, and re- 

 maining under its influence, but as being of a foft- 

 er texture -, nor can minerals, leaft of all the ful- 

 phureous and bituminous, refift its action : nay, 

 thefe are chiefly the bodies on which it performs 

 deftructions, feparations, and new combinations, 

 as fufliciently appears from vitriol and alum. la 

 the depths of the earth it operates on minerals more 

 powerfully than at the day, as being not only more 

 actuated with a greater number of faline particles, 

 but not fo fubject to be difilpated by the action of 

 the wind and fun, confequently it has time and 

 leifure to eat into veins and rock •, nay, to deftroy 

 fuch bodies as, expofed to the open air, remain 

 untouched, or become ftill harder, and more du- 

 rable. It not only penetrates, but at the fame time 

 adheres to what it penetrates, with its fatty, faline, 

 earthy and watry particles, which laft are the ve- 

 hicle wherein the others lodge, and are introduced 

 and incorporated into the fubject. The fatty and 

 faline nature of the air cannot be difallowed by 

 any one, confidering its meteors, in particular, 

 thunder and lightning, the habitude of pot-afh 

 thereto, the corrofibiiity of iron and copper there- 

 in, C5Y. Only 'tis here to be hinted, that we do 

 not extend too far the action of the acid of the air to 

 the vitriolifation of pyrites, as being what is al- 

 ready plentifully prefent in the fulphur of the py- 



Q rites ; 



