Elements of Mineralogy^, 



coal i an inch thick at bottom, and ~ on the 

 fides, fimply covering it with calcined borax, 

 luting on this another crucible, which healfo 

 expofes to the heat of a fmith's forge. 



49. Argillaceous and filiceous iron ores 

 rnay be eflayed in the following manner: 

 take of the ore 4 parts, quick lime 1525, 

 fluor fpar 1,25, powdered charcoal i, decre- 

 pitated common fait 4 ; the whole, being 

 well mixed, place in a crucible lined with 

 charcoal, to which a cover fhould be luted* 

 and the lute being dry, commit it to a 

 fmith's forge, giving a moderate heat for 

 J of an hour, and the ftrongeft for the re- 

 mainder of the hours if the lime be flacked, 

 double the quantity muft be ufed. 6 Crcll. 

 Nev. Entdeck. 



50. Calcareous ores may be treated in the 

 fame manner, except that inftead of quick lime 

 double the quantity of fluor mould be ufed. 



51. Pyritousores are alfo eflfayed nearly in 

 the fame manner ; the proportions being 4 

 parts of the ore previoufly roafted, 2 of quicl^ 

 lime, 2 of fluor, if of charcoal, and 4 of 

 decrepitated common fait. Ibid. 



52. Iron ores, which, though at firft 

 bright in their frafture, foon grow black by 

 expofure to the air, contain much man- 

 ganefe. 



53- 



