the lStaniifa8,urc of Crude Iron. j^f 



Vtoxw this it will appear evident, tliat the addition of cal- 

 careous earths, injult proportions, will form with moil ores 

 a vitrid alloy, thinly divided, and to which the metal has lb 

 little affinity, that it hccomes abandoned by the former at an 

 early llage of fcparation, and, being expc/fed to the combina- 

 tion of the carbci, is beneficially and richly revived. In 

 this operation lime may be confidered as introducing into 

 the furnace a confiderable quantity of carbonic acid, [it is 

 always ufed in the raw ftate] which becomes decompofed in 

 fuch a manner as to furnifh the iron with a fmall portion of 

 carbonaceous matter. The eftefls of this extenlion of prin- 

 ciple are how^ever much limited, as the carbon afi'ordcd by 

 the decompofition of the carbonic acid can never enable the 

 iron to take up this principle from it in a crude concrete 

 flate, capable of conftituting fufibility. It may, however, by 

 uniting to it in a neutral ftate, call it into metallic exiftence, 

 and enable tlic carbon afforded by the fuel to diftribute its 

 fufible principle over a larger portion of metal. Lime-flonc^ 

 therefore ought never to be confidered as a general fubftitute 

 for fuel in the blaft furnace, though in fome cafes the cffecls 

 produced by its application are fimilar. Its influence extends 

 no farther than to correal the unequal mixtures of fome ores, 

 and facilitate tlieir feparation and carbonation ; an improper 

 application of its kind or quantity may be produAive of 

 evils of as great magnitude as thofe it was meant to remove. 

 In no cafe where a jufl proportion of ores and mixtures cxift 

 in the furnace, and where the refult from a real fcarcity oi 

 fuel is oxygenated iron, can the addition of lime confer car- 

 bonation to the metal. 



'riiefe fufts render thx; application of lime-ftone a matter 

 of attention, ami not of chance, depending on an accurate 

 knowledge of the component parts of the ores and their 

 eflfecls, and not on certain portions being cuflomary at 

 works of fimilar cflabliniment. When a fcarcity of lime 

 i:\ilu in the blaft furnace, and a fuperior quantity of clay 



and 



