of the Pyrites. 253 



determined juices and damps, which, by their 

 conflux and coction, firft of all become either iron- 

 earth, copper-earth, fulphur,. arfenic, gold, or 

 filver, as now extant in the prepared pyrites. 



Upon a general view of the fubterraneous ore- 

 productions, particularly drufe and Jinter, we (hall 

 find three forts of ftone, and as many ways of their 

 production and generation. 



The firft is an induration or condenfation of dry, 

 earthy, but tender, porous, and powdery parti- 

 cles, by which an earth may be baked, and be- 

 come of the hardnefs of ftone, by means of air 

 and water, as I have reafon to be fully fatisfied by 

 indubitable figns from the atites. 



The fecond is a precipitation of earthy particles 

 out of water, by means of its running and trick- 

 ling down, whence arife the Jinter flcs ferri and 

 ftaladites \ not out of muddy, but the moft tran- 

 fparent fpring- waters, in which the earth lies ftrew- 

 ed up and down in the moft tender manner, fo as 

 to efcape not* only the fight, but the clofeft ftrain- 



The third is a cryftallijation, where ftoney, both 



flinty and fpathy particles, intimately diftblved and 



mixed in the water, like a fait, moot out of the 



moft tranfparent cryftal waters, by means of reft, 



and by length of time; confequendy, by the moft 



.rely and unobfervable evaporation of the moi- 



fture into formal, faline cryftal s ; as I have fully 



Je appear in chap. V. In this alfo Dr. Wood- 



d agrees, with refpecl to the production of 



dmfe, mowtain-cryfiaUi &c. 



But 



