Cf /^Principle s, &c. 245 



What we now propofe is, in (hort, to learn 

 Lt particles the iron, copper, crude-earth, 

 fulphur, arfenic, gold, and filver in pyrites coniift 

 of. Speculates, ever fond of enquiring into what 

 is called the principles of things, may be apt to 

 think we fhould have kt out with, initead of hav- 

 ing poftponed 'till fo late this enquiry. Thefe pre- 

 poiierous enquirers into nature, ever at the en- 

 trance upon their difquifitions, fall to explaining the 

 principles of their fubjects, before they have once 

 duly examined their mixt parts, much lefs their 

 forms, proportions, habitudes, connections, di- 

 vifions, productions, &c. To lay fo great a flrefs 

 on things quite out of the reach of our fenfes, as 

 principles, in truth, are, and overlook what our 

 fenfes are proper judges cf, is but the high road 

 to endlefs conceits and imaginations ; one fingle 

 proportion, fairly deduced from experiments, be- 

 ing far preferable to, and more valuable than all 

 thofe imaginary theories, which have neither experi- 

 ment, nor other folid foundation for their iupport : 

 and though it may not be unufefu! to reafort about 

 things, yet we fhould proceed in fuch a manner, 

 that the reader may be led, as by a clue, from 

 the proximate to the remote principles, from the 

 mixt parts to the fimple, and thus in a retrogade 

 order, namely, that in which v/e treat the fubjecl: 

 under experiment. 



Id take all the parts educed 

 - in the largeft view poffible, thefe ei- 

 ther exifced already in the mixtion thereof, and 

 thus are actually feparated, or are new-produced 

 in the act of feparation, or rather of the deftruc- 

 tion of the pyrites^ or elfe they exifted in the fo- 

 rties in diftinct parts \ the former are iron-earth, 



R 3 copper- 



