Iron » 
191 
viz. 2*056 lb. used for the manufacturing of every pound 
of cast iron is reduced to grains, we will find it to consist 
of 14392 grains ; this, divided by 28, gives the acidifiable 
principle of 514 x 100 = 51400 grains of carbonic acid 
gas;* hence, as 1 cubic foot of this gas, at 29*84 of baro- 
metrical pressure, and 54*5 of temperature, weighs nearly 
761 grains, we find, that in the formation of every pound of 
cast iron = 67*54 cubical feet of carbonic acid gas 
will be formed, and in the production of 1 ton of metal ? 
the astonishing quantity of 151289*6 cubic feet. This 
quantity, however incredible it may seem, is only what 
would be formed under the above pressure, and at the 
above temperature : when we take into the account the 
high temperature at which the decomposition and recom- 
bination are effected, with the consequent increase of elas- 
tic force and of volume, our ideas are almost unable to 
commensurate the sum of the gas hourly formed, and 
thrown off, ignited to the highest degree of heat. 
If the same mode of calculation be adopted with the other 
qualities of coal, we shall have the following results 
For the splint coal 2,442 lb. or 
17094 
"~ 28 ™ 
610,5 x 
* This is supposing, for the moment, that the whole of the car- 
bon is oxygenated, either by the oxygen contained in the ore, or 
obtained from the discharging-pipe by the decomposition of the 
atmospheric air ; this, however, is not strictly true, as the metal 
takes up a small portion, by weight, of the carbon ; and when, by 
accident, moisture has been introduced into the furnace, either 
through the m edium of the blast, or of the m aterials, its decompo- 
sition furnishes a portion of both oxygen and hydrogen, which 
may dissolve, and also carry off, a part of the carbon. Atmosphe- 
ric air being found to hold water in solution, a small quantity of hy- 
drogen will, even in the driest weather, be present in the blast-fur- 
nace. M. 
