iW A SYSTEM OF 



of the fame bulk or volume as the coal 

 was. 



From England, and among the alum 

 rock at Moltorp and Billingen in the pro- 

 vince of Weftergottland. 



SECT. CLX. 



3. "With abundance of argillaceous earth, 

 Stone coal. It burns with a flame by it- 

 felf, otherwife it looks like other flates. 

 It is found at Gullerafen, in the parifh 

 of Rettwik, in the province of Da- 

 larne, and alfo with the coals at Boferup 

 in Skone *.• 



SECT. CLXI, 



6. Mineral phlogifton mixed with metallic 

 earths, Phlogifton minerale metallis impreg- 

 natum. 



This is not found in any great quantity : 

 in regard to its external appearance, it re- 

 fembles pit-coal ; and the fat fubftance con- 

 tained in it, at times partly burns to coal, and 

 partly volatilizes in a calcining heat. 



The only known varieties of this kind are, 

 A. Miner a cupri phlogiftica. 



When it has been inflamed, it retains the 

 fire, and at laft burns to allies, out of which 



* This laft mentioned kind has induced me to believe, that 

 the earth of the pit-coals is an argillaceous one, but is not fo 

 eafy to be difcovered after its being burnt. The pit-coals 

 contain more or lefs of the vitriolic acid, for which reafon the 

 fmoak arifing from them attacks filver in the fame manner as 

 fulphur does ; though the coals be ever fo free from marca- 

 fite, which however is often found imbedded or mixed with 

 them. 



purs 



