3^4 On Primary Ores of Iron. 



parated from the charcoal, wafted and dried, weighed 222*5; 



the charcoal having taken up 59*5 grains = 21 per cent. 



In this [late the ore had loft all its colour, and had aflumed 

 a whitifh limey tinge; had increafed in bulk, and become 

 frittered, yet poficfhng a coniiderable degree of continuity : 

 when the fmalleft degree of friction was applied, the metal 

 brightened, and (hewed a beautiful difengaged ftate of mal- 

 leable iron; the pieces eahly connected under a welding heat, 

 and received with facility mtpreffions from the hammer; it 

 now adhered irt great abundance to the magnet. The fmall 

 portion of lime, hearty equal to two parts, which was hull 

 iiiterfperfi I w ' fFervel ' in* acids; but the iron re- 

 mained without exciti The practical analyfis of 

 this fpecimen of the Elba ore may, for the prefent, be thus 

 hated : 



Water, carbonic acid, and other volatile mixtures, driven 



off by torn-faction - - 107 



Oxvgcn (taken up by the charcoal) - 2 1 '2 



Time - - - 2 



Iron - - 66-1 



100 parts. 



The fpecilic gravities of the various hates of this ore arc 

 as follows: — In the raw ftate, 4*317 — Torrefied, 4-000 — 

 De-oxvgcnated, malleable, much frittered, 2 - 46o. 



In the fubfequent part of this paper, I fhall confine my- 

 felf chiefly to thofe primary ores ufed in Britain for the pro- 

 duction of crude iron. The effects produced by fuch ores, 

 v. hen fufed alone, are only to be learned in this country, at 

 thofe iron-works where the charcoal of wood is ufed. The 

 number of charcoal furnaces however are decreahng; and 

 thole at prefent ufed as fuch, are not fupplied with wood for 

 tone-third of the year. Thefe ores are, in the charcoal fur- 

 nace, capable of producing crude iron of all the various de- 

 grees of caibonation. Since the invention of coak pig-iron, 

 .tiu- prvpuetors.ef thefe furnaces have confined their manu- 

 facture 



