The Subject Propounded.' 5 



with raife better fyftems than we are at prefent pof- 

 Tefled of. 



Of what confequence chemical enquiries into 

 nature may be, will appear from fome difcoveries 

 I have accidentally made, in my examination of 

 the pyrites -, from which, and a certain kind of 

 earth, each feparately barren of filver, I procured 

 an actual filver : alfo from pyrites itfelf, a fteel 

 tincture peculiarly fweet, and without that rough- 

 nefs, common to fuch tinctures ; alfo from my en-: 

 quiries into the nature of the pyrites, I have gained 

 no fmall degree of knowledge in the bufinefs of 

 fmelting ores. 



As to my method of procedure in the pre- 

 fent enquiry ; I have, in the firft place, laid it 

 down for a rule to myfelf, to abide ftrictly by 

 matters of fact, without giving into any hypo- 

 thecs or empty fpeculation whatever ; and, there- 

 fore, I attempt not to feparate or refolve the />jy- 

 rites, either into the four elements, the three, 

 or other imaginary principles •, as being things 

 that can never be made objects of our fenfes ; 

 or that any one can lb explain, as to convince 

 an impartial enquirer, trial thefe are the efTential 

 condiment parts of our fubject : a rule as in- 

 difpenfibly neceffary, as it is generally but little 

 regarded. 2. I have put the pyrites to feveral 

 accidental proofs, and by that means often dis- 

 covered, what I otherwife could never have hoped 

 for. That from the acid vitriolic-falt, and the al- 

 caline earth of the herb Kali or Soda, a blue 

 colour mould be procurable, is what no one 

 could beforehand fufpect : as little, as that the 

 pyrites mould yield a fweet iron-tincture ; or, thas 

 a fpecies of earth, in itfelf deftitute of filver, 

 fhould, by means of the pyrites, become re- 

 markably filvery. 3. I never fcrupled feverai 

 times to repeat a fiagle experiment i either up- 



B % 03 



