Iron, 
105 
jj 
portion to the reduction of the quantity of ore used. In 
24 hours the quantity of the pig-iron produced, averaged 
48 cwt. of carbonated crude iron. As this is the quality 
of metal which serves as the basis of the calculation in 
Number XX. of the Philosophical Magazine, it will be 
the most proper standard to compare the widely different 
effects produced by wood and pit- coal. In that Number 
a table is given of the quantities of crude iron each variety 
I of coaks produce, and which, for the sake of immediate 
! comparison, I shall here again insert. 
I ton, or 22401b. clod-coal coaks produces 
of carbonated iron - 10401b. 
1 ton, or 22401b. splint-coal coaks - 840 
— — — 2240 mixed coals - - 702 
1 ton, or 22401b. of charcoal of wood, ac- 
cording to the proportions furnished 
above, will produce of carbonated iron 2986 
1 ton, or 22401b. of the same, w ill produce 
of oxygenated crude iron for forge- 
pigs - 3718; and 
1 ton of carbonated pig-iron will require 
of the coaks of clod-coal - - 4 824* 61b, 
— — splint- coal 5973*3 
— . — — - — mixed - - 7147*5 
- — - — — — wood charcoal - 1680 
From this comparative view it is found that charcoal 
of wood produces triple effects, or carbonates three times 
the quantity of crude iron that the clod- coal coaks do ; 
three and a half times as much as the splint ; and four 
and a half times as much as a mixture of free and splint. 
The next consideration is the price of the two fuels. 
Charcoal of wood, about forty years ago, sold at 2s, 6d, 
per sack of 1 cwt. or 50 s, per ton. 1 ton of good splint- 
coal coaks will be prepared on many of the present iron- 
work banks, labour included, at 11 s* and at some places 
O 
