Steel 
259 
ly also to the ores, calces, and precipitates of many me- 
tals ; it is found also as the base of the carbonic acid gas 
which exists in the atmosphere in the proportion of about 
one part in 100; also in the gas which is produced dur- 
ing the fermentation of vegetable substances ; in the air 
expired from the lungs ; in the air evolved from burning 
fuel ; in the choak damp of wells and mines ; and perhaps 
j in some other ways, not necessary to be noticed here. In 
|| all these substances whether solid or aeriform, the carbon 
or pure charcoal is one and the same thing. 
Carbon united with oxygen in a high degree of heat, 
becomes carbonic acid gas, the choak damp of mines, 
which extinguishes flame, and animal life, and exhibits 
slightly acid properties* The form of air or gas, which 
! the carbonic acid puts on, is owing to its combination 
with caloric or heat 
The method of ascertaining how much carbon exists 
in a given substance, is by uniting it with oxygen, (or the 
pure air which forms 21 parts in 100 of the atmosphere) 
and then ascertaining the quantity of carbonic acid gas 
produced ; this can be done by means of lime water, 
which absorbs the carbonic acid gas, and the lime becomes 
again limestone. For lime is limestone deprived by fire, 
of water and carbonic acid. 
The method of acertaining how much carbon or pure 
charcoal is contained in iron or in steel, is by dissolving 
a given weight (100 grains for instance) in oil of vitriol 
diluted with six times its bulk of water, which will dis- 
solve theiron and leave the carbon or charcoal undissolv- 
ed in the form of a black powder. 
The rough method of making charcoal, is by piling bil- 
lets of wood on an earthen floor, leaving an opening in the 
middle of the pile by means of placing the billets slanting 
toward each other, so as to make the pile nearly a cone 
with a wide base* Fire is put in at the top of the middle 
