of the Pyrites, 257 



layer, muft be confidered as the matrix of the next 

 above it. Befides, it is not to be denied, but that 

 there are beds, or rather productions, where, ac- 

 cording tc all appearance, the under and over lay- 

 er contribute neither pofitively nor negatively to 

 the production of pyrites*, that is, neither promote 

 nor hinder it, but the damps contribute all -, nay, 

 even to the flrft earth of Becher, and thus to the 



ground-work of the ore. 



«^> » 



Leafr of all is nature to be here confidered as a 

 common mechanic, who has all his materials ready 

 prepared, and only puts them together : for, tho* 

 the gurs, or mineral juices, and finter^ among 

 which are claiey and ochry matters, are, and may 

 be matrices, yet fuch marly, ochry mineral juices 

 mud not be fuppofed to exclude other earths and 

 ftones. 



In a word, ores certainly have a matrix -, firfr, 

 a fitly adapted place ; again, a matter not quite 

 dead and motionlefs, but emitting its efficacy and 

 emanations on fomething, or at leaft is a receptive 

 matter. In and upon fuch earth and itone may 

 ore and metal be produced, but neither can fuch 

 earth or Hone themfelves turn to ore or metal ; 

 which matrix, whether the ftoney or earthy, con- 

 tributes more material damps, is a queftion not 

 fo eafily refolved : the anfwer, however, feems to 

 favour the lad more than the firft ; as what is ten- 

 der, foft, and yielding, is more fitted for the 

 change happening here, than what is clofe, hard, 

 and ftoney. v 



But in all thefe out -weatherings , or exhalations, 

 either from the under or upper layers, either po- 

 rous, flimy or clofe 5 that is, either earthy or ftony 



S matrices,- 



