from the Pyrites. 329 



alcali \ and the more fo, the more it is fet free 

 from its vitriol- mixtion by continuing the evapo- 

 ration. 



That thefe do no fooner lay hold of each other, 

 muft be owing not only to their difperfion, but alfo 

 to the over-proportion of water. For, as foon as 

 only a little of the water is evaporated, fo foon do 

 thefe antagonifts fall upon each other, after having 

 hitherto remained fo long in peace. Now, as the 

 acid fooner, and more firmly unites wick alcali 

 than with metallic earths, fo here the acM lets go 

 the metal under the form of a yellow earth* and 

 combines with the alcali. 



Here I mean only fuch waters, where, along 

 with the vitriol^ the alcali manifeftly lodges, as is 

 generally the cafe in medicinal fprings : but mould 

 you meet with vitriolic waters, affording no fuf- 

 picion of an alcali, nor exhibiting any •, and yet 

 the vitriol^ after a degree of evaporation, coming 

 to be deftroyed, as mall fufficiently appear by the 

 precipitating yellow earth, there mull be other 

 reafons of this appearance, or your experiment 

 has not been accurately gone about. - 



If no formal alcali can be exhibited, it muft then 

 be common fait their presents its alcali \ whereby vi- 

 triolic waters turn eafily muddy and ochry ; again, 

 if no common fait, it muft be fomething earthy, 

 without participating of which a ground-water 

 feldom is found, to which, if the vitriol acid does 

 not fallen, yet in r :ofine contiguous, fo as 



to let fall its metallic cart! h does not hold 



very firm thereto : and if there is no precipi- 

 tation, yet waters generally, by long boiling, 

 leave behind an uncaious, fatty, brpwniih liquor, 



tailing 



