for Ma?wfafiurl?ig Cafl Iron. . 23 



Iroii-flone. 

 The fubftitution of pit-coal in the blaft-furnace, in place 

 of the charcoal of wood, firft introduced to general ufe thofe 

 numerous ftrata of argillaceous iron ores found ftratified 

 along with the other fecondary formations of our globe. The 

 intimate connection which nature had impofed upon thefe 

 two mineral Jubilances, by the plentiful formation of them, 

 almoft always within convenient reach of each other, has 

 been fuccefsfully traced and beneficially developed in their 

 mutual application to the manufa&uring'of caft-iron. 



Had nature not formed this immenfe ftore of iron fo con- 

 genial to the ufe of pit-coal combined in. its prefent form, 

 the application of caft-iron to the various branches of ma- 

 chinery, and to the vaft variety of ufeful and ornamental call- 

 ings conftructed for the conveniences and elegancies, had 

 been greatly retarded, if not hitherto altogether kept back. 

 At prefent it is by many believed— nor has any attempt in 

 the large way ever contradicted it — that primary ores of iron, 

 fuch as the Cumberland and Lancaihire ores, are incapable 

 of affording caft-iron fufficiently carbonated, when fmelted 

 alone with pit-coal coaks, to be re-melted to advantage in the 

 manufacturing of callings*. Certain it is that a larger por» 



* I have not heard of any attempt to produce carbonated caft-iron from 

 thefe ores in the large way. The univerfal diffufionof iron-ftones renders 

 this fupcrfluous; efpecially as the ufe of Cumberland and Lancafhire ore 

 can only extend to the neighbourhood, or at moft can only be ufed by 

 ftrangers whofe works are within the reach of water-carriage. Their ad- 

 vantage therefore would only be local, and their utility reftric~led by the 

 expence of carriage, of freight, or of both. As to the qualitv of iron they 

 contain, I have not a fcruple in averting, that it can be called into ex* 

 iftuiceby means of the aflay-furnace fufficiently carbonated, even to ex,- 

 cefs, for any purpofe. From thefe ores I have obtained reguli of fuper- 

 C3ibonated crude iron covered with numerous fpecks of plumbago. The 

 fame refults being obtained from iron-ftones in the fame manner, though 

 with a different application of folvcnts, am I not at liberty to deduce, that 

 fimilar effects could be produced in the large way, by varying the treat- 

 ment and proportion of materials} Vide Affaying of Primary Ores by 



C4 ti°« 



