4^ On the Origin and Progrefs of the 



From this comparative view it is found that charcoal of 

 wood produces triple effetSls, or carbonates three times tl>e 

 quantity of crude iron that the clod-coal cokes do; 3^- times 

 as much as the fpHnt; and 4^ times as much as a mixture 

 of free and fplint. 



The next confideration is the price of the two fuels. Char- 

 coal of wood, about forty years ago, fold at 2s. 6d. per fack 

 of 1 cwt. or ^os. per ton. i ton of good fplint-coal cokes 

 will be prepared on many of the prefent iron-work banks, 

 labour included, at 115. and at foinc places fo low as 10^. 

 At prefent the price of charcoal is upwards of 4/. per ton. 

 So that at this period, although the cffeils of wood are 3 )- 

 times thofe of fplint-coal cokes, yet the price of one ton of 

 charcoal wood will purchafe eight tons of cokes; the quan- 

 tity ot ihc former limited to, and produced from, land which 

 might be better applied to the purpofes of agriculture ; the 

 latter found in innnenfc fields, and in tra6ls of country which 

 are always augmented in value by the development of their 

 mineral treafure. 



A charcoal blaft-furnace which fmeUj the whole year 

 round, and occafionally makes forge-pigs and carbonated 

 iron to the amount of icoo tons annually, will confume 

 I4j000 facks of charcoal ; which may be eftimated at i cwt. 

 per fack, or 700 tons, or 1,568,0001b. This divided by 

 1,8.751b. the pounds in a cubic foot, gives for the quantity 

 of timber in cubical feet, 83.626. Tliis is going upon a 

 former calculation, and is fuppofing the wood to fhrink but 

 little during the procefs of charring. In the prefent ftate of 

 the woods which are attached to iron-works, one acre will 

 not yield more than 1300 cubical feet of timber; To enfurc 



the annual fupplv, -^—^ = 69.60 acres of land would re- 

 ' ' 1200 



quire every vear to be cleared, or nearly 1400 acres would 

 be requifite to form, with proper care, an unfailing fource of 

 fupply ; and at the rate of 4/. per ton, the fuel would coft 

 2,800/. 



Let this be compared with a blaft-furnace manufafturing 

 the fame quantity and quality of coke pig-iron. The ave- 

 rage quantity for each ton will be nearly fix tons of fplint, 

 er, as they lofe 50 per cent, in charring, 3 tons of cokes 

 9 X 1000 



