356 On Primary Ores of Iron. 



my, provided the great end could be anfwered of obtaining 

 from them crude iron of all the various degrees of carbonation, 

 Thefe ores, either in a raw or calcined ftate, being much 

 richer in iron — nearly double — than the average mafs of 

 iron-ftones, are in the blaft furnace more fufible, from their 

 fuperior richnefs ; they defcend fo rapidly to the bottom of 

 the furnace, through the ftrata of ignited coaks, that time is 

 riot given for imbibing the carbonic principle ; part of the 

 iron is feparated highly oxygenated, and part of it runs oft 

 precipitated in oxygen, and united with the fcoria or fufed 

 earths. When this is found to be the cafe, and which is 

 eafily known by the fracture, weight, and blacknefs of the 

 lava — were the manufacturers to add a farther proportion of 

 fuel to take up the remaining oxygen, then the whole, or 

 nearly the whole of the metal would be revived ; ftill it 

 would poffefs a white fraclure. Were the Cumberland and 

 Lancafhire ores fblelyufed with pit-coal, were they deprived 

 of their iron, and again that iron revived, though poffeffed 

 of a highly oxygenated fracture, the great object would be 

 half effe&ed ; for it is obvious, that in this cafe the furnace 7 

 and the quality of iron, are in the fame ftate with a blaft 

 furnace, affording a fimilar quality of metal where iron-ftone 

 and pit-coal coaks only are ufed. In the latter cafe a fmall 

 additional portion of fuel, per «harge, enables the metal to 

 take up a part of the carbon afforded by the fuel : the fracture 

 of the metal is, by this combination, or mixture, changed 

 from white to grey blue \ its affumption of this colour is in 

 proportion to the extra quantity of fuel. From this fact, and 

 from the parity of fituation, I conclude that by a fimilar 

 treatment — the additional fuel being always proportioned to 

 the weight of metaHn the ore — the metal of fuch ores might 

 be revived fufticiently carbonated for any purpofe ; though,. 

 Iqueftionnot, poffeffed of peculiar characteristic properties,, 

 which would diftinguifh this metal, in a greater or lefs de- 

 gree, from that obtained from iron-ftones treated in the 



fame manner. 



Accuftomcd 



