On Primary Ores of Iron. 359 



defcending through which, the ore, previous to fufion, would 

 be expofed to a long cementation in contadt with the coal ; by 

 which means the carbonaceous or fuiible principle would 

 be conveyed to the metal in quantity, and its quality thus 

 conflituted previous to reparation. 



and. The column of air neceflary in this cafe would require 

 to be cool, denfe, and quickly impelled; the diameter of 

 the difcharging pipe not to exceed %\ inches, but the column 

 of blaft able to fupport 6, 6], or 7 inches of mercury. 



3rd. In the application of the ore itfelf great attention 

 ought to be given to the quantity of iron contained, as alio 

 to the quantity of oxygen combined with it, in order that 

 a quantity of coaks might be applied adequate to what a 

 fimilar portion of iron would require in ufing iron-ftone. 



4th. The ore mould be dried in a red heat, that what portion 

 of water and fulphur it contained might gently be difiipated ; 

 care to be taken, however, to prevent a high degree of heat, 

 that a greater quantity of oxygen from the atmofphere might 

 not be united to it. 



5th. It would be highly proper to reduce the ore to fmall 

 pieces : this would not only greatly facilitate the efcape of 

 the water and fulphur by diminifhing the points of contact, 

 but alio, by expofing a larger furface, enable the ore in the 

 (melting furnace to take up the coally principle with greater 

 facility ; the pieces not to exceed k or | of an inch in their 

 thinneit diameters. 



6th. The earthy mixtures of ores being chiefly filiceous, 

 the application of pure calcareous earth as a flux or fol- 

 vent would be requifite ; and, according to exiftent circum- 

 ftances, a lime-Rone, containing fine clay, nightly coloured 

 by the prefence of the oxvd of iron, might be ufed : the 

 bulk of the pieces of lime-Hone ought alio to be a matter of 

 attention, and ihould not greatly exceed the ore in fize. 



in the end, ihould an aflbciation of thefe requisites pro- 

 duce the defiied efledt, and crude iron of all the various 

 ps of carbonation be obtained from primary ores of 

 \ a 4 iron, 



