Tron-Stones ufed at the Blaft-Furnace. 369 
tain 3°3 parts of afhes; and 100 parts of cokes contain nearly 
6°5 per cent. of alhes, which, deducted from 7147°3, gives 
6672°6 of carbon, which divided by 2240, gives, for the quan- 
tity ufed for 1 1b. of caft iron, 2°9g781b.  * 
From thefe calculations it appears, that 2240 lb. of carbo- 
nated iron, requires of carbon from clod-coal 4607 1b.; of 
carbon from fplint-coal, §4721b.; and of carbon from mixed 
coal, 6672 1b.: that 1 lb. of carbonated iron requires of car- 
bon from clod-coal cokes 2,056 lb.; from fplint, 2,442 Ib. ; 
from mixed, 2,983 lb.: and that carbonated crude iron may 
be obtained when widely different quantities of carbon have 
been confumed. 
In feeking for a folution of the latter fut, we muft have 
recourle to the different degrees of inflammability of the car- 
bon, according to the various laws of continuity impofed upon 
it in its foffil conftru@tion. It can eafily be conceived, that, 
owing to this ftruéture, and the nature of the mterpofed 
afhes, the particles of carbon of fome cokes will be more 
eafily oxygenated than thofe of others ; in the fame way that 
we find fplint-coal, when expofed to ignition in contact with 
open air, affords 1-3d of more cokes than are obtained from 
foft mixed coals, though the latter, when diftilled, yields more 
pure carbon than the former. 
By experiment it is proven, that roo grains of carbonic 
acid gas is compofed of 72 parts of oxygen united with 28 
parts of carbon: if the quantity of the carbon of clod-coal, 
viz. 2°056 |b. ufed for the manufacturing of every pound of 
caft iron, is reduced to grains, we will find it to confift of 
14392 grains; this, divided by 28, gives the acidifiable prin- 
ciple of 514 X 100 = 51400 grains of carbonic acid gas *: 
* This is fuppofing, for the moment, that the whole of the carbon is 
oxygenated, either by the oxygen contained in the ore, or obrained from 
the difcharging-pipe by the decompofition of the atmofpheric air: this, 
however, is not ftriétly true, as the metal takes up a fmall portion, by 
weight, of the carbon; and when, by accident, moifture has been intro- 
duced into the furnace, either through the medium of the blaft, or of the 
materials, its decompofition furnithes a portion of both oxygen and hydro 
gen, wbich may diffolve, and alfo carry off, a part of the carbon. Atmo- 
fpheric air being found to hold water in folution, a fimall quantity of hy- 
drogen will, even in the driet weather, be prefent in the blaft-furnace. M. 
VoL, V. 3B hence, 
