MINERALS. 9 



IT IS very rarely, and indeed fcarcely ever, that the Species can be 

 fufficicnily detcrmin.d, fince in thefe the generation proceeds not 

 frotn the egg 5 bnt the multiplied variety of irregularly fporrive 

 nature, is at once the calamity of the fcicnce and the foundatit)n -»£ 

 metallurgy. He therefore that (hall ralhiy endeavour to multiply 

 the rpecies, is not lefs abfurd than him who combines fubltances 

 totally diifcrent in nature. Nor does their matrix diilinguilh the 

 different fpccics, more than their natural fituation and foil do the 

 plants of the earth. The numerous diverfities of Itones, therefore, 

 are principally varieties; in the arrangement of which, without 

 caution, it is eafy to fall into error. 



THE (Indent has three modes of Invedigating this King-^om: Phy-- 

 ftcal, which defcends through the obfcure generati')n of mitierjis : 

 N'ituraly which confidirs their fuperficial and vifible flru6lure : 

 Cbemicali which afcends throut^h their deftru6live analylis \n 

 this then, as in every thing elfe, he will molt fafeiy fo low the 

 middle courfe, and by clofely follovving his ariadnean thread, he 

 will not, like an empyric, confound the fymptoms with the cure, 

 nor bring forward the doubtful progeny of a long loft anccltry ; 

 much lefs will his terrified imaginati n raife up fanciful fpcdtrcs 

 in the dark, or perluade him that the Phoenix of the poets may oe 



• regenerated from its own alhes : but he will learn, what names 

 are repugnant to thing?, and what are convetiient ; and how to 

 define charaders by their diagnoilics, and not merely by their ety- 

 mology. But here let me pauf/, left in endeavQuring to remove 

 obfcurity, I myftlf become ojfcure. 



VOL. VIL -r- 15 



