368 On the relative Proportions of Coals and 
Then, for the quantity of the refpeétive coals ufed in the 
raw ftate, we have the following refults in proportion:— 
T. C. Q be 
Clod-coal 5:4824°6 :: 8: 77193 = 3 8 219 
“Splint-coal 4: 59733 :: 8: 11946 = 5 6 218 
Mixed coal 3:7147°1 :: 8 : 19158} = 8 11. 0.16 
Thefe great difproportions of quantity, ufed to fabricate 
"Aton, or 2240 averdupoife pounds of the fame quality of 
crude iron, will convey a ftriking and impreffive idea of the 
multifarious qualities of coal which may be applied and 
made to produce the fame effects. It fhould alfo convince 
the manufacturer that the ftudy and analyfis of his own ma- 
terials is the firft and radical approach to true knowledge, 
and certainty of operation. Diveft him of this knowledge, 
and view him guided by the cxfloms and rules prevalent at 
another manufactory, where the coals and ores may be as 
different as has been already mentioned, and we will no 
longer wonder at the uncertainty of his refults, and the num- 
berlefs errors of his direétion. 
Before I enter into the praétical difcuffion of the applica- 
tion of coal, I beg leave to indulge myfelf in the following 
calculations :—We have already feen that the production of 
2240 lb. of carbonated crude iron requires 4824 lb. of clod- 
coal cokes; thefe may be averaged to contain 4°5 per cent. of 
afhes, which, deducted from 4824, gives'4607 Ib. of carbon 
ufed for 1 ton of metal: this fum, divided by 2240, farther 
gives, for 1 tb, of caft iron thus a vaPSAI tte 2" 058 Ib. of 
carbon. 
We next find that 2240]b. of the fame metal requires of 
fplint-coal cokes 5973°3 !b.; we farther find, from a table of 
the analyfis of coal, furnifhed in a former paper, that 100 
parts of the raw coal contained 4°2 parts of afhes. As it is 
there ftated to lofe 50 per cené. in charring, 100 parts of 
cokes will contain 8-4 of afhes; and 8-4 per cent. deducted 
from 5973°3, gives 5472 ]b. of carbon. This again, reduced 
by 2240 |b. gives for each Ib. of metal manufactured, 2°442 1b. 
Again, 71471 lb. of cokes produced from foft mixed coals 
are confumed for every ton of 2240 averdupoife pounds of 
crade iron produced; every 100 parts of the fame coals con- 
tain 
