1 5& Of the Sulphur 



lead increafe, but alfo unaltered in colour and mal- 

 leability, and therefore not the leaft penetrated by the 

 fulphur. What unfits iron for receiving the ful- 

 phur, is its eafily burning away, and turning to an 

 earth, fooner than copper, whereby the due intro- 

 duction of the fulphur into it is prevented. 'Tis 

 true, copper, by the art of ignition, becomes covered 

 over with a kind of ruft, or fcales, which at length, 

 are eat thro' or penetrated by the fulphur ; whereas 

 iron will receive none of it, only fufrering it to fettle 

 a little externally thereon, be the degree of fire as 

 great again as for the copper, and thus be the in- 

 grefs of the fulphur facilitated as much as may 

 be. 



Here might be expected a fuller and more par- 

 ticular examination and defcription of fulphur * but 

 as this would require a great deal of time and la- 

 bour, befides, not properly belonging to our pre- 

 fent undertaking, where I enter not into a particu- 

 lar detail of the parts of the pyrites , I wave it. My 

 defign is the analyfis of the pyrites, not the hifcory 

 of each conftkuent part in particular; though, on 

 the fcore of inferences, connection, and other cir- 

 cumftances, I could not always avoid the hinting 

 at this, and fome other matters, not immediately ne- 

 cefTary to the knowledge of the pyrites. 



A reader defirous of fomething peculiar, funda- 

 mental, and explicit on the head of fulphur, may 

 confult Stahl, in his Bedencken vom fulphur e, his 

 Specimen Becherianum, his Men/is Julius de experi- 

 ment o novo verum fulphur arte producendi •, where he 

 will find full fatisfa&ion. 



There ftill remains to be confidered M. Hom- 

 berg's relation, in the memoirs of the Royal Aca- 

 demy 



