substances. It takes fire at the temperature of 32 (104 ) of the
thermometer.
TABLE _of the Binary Combinations of Charcoal._
_Simple_
_Substances._ _Resulting Compounds._
{ Oxyd of charcoal Unknown.
Oxygen { Carbonic acid Fixed air, chalky acid.
Sulphur Carburet of sulphur }
Phosphorus Carburet of phosphorus } Unknown.
Azote Carburet of azote }
{ Carbono-hydrous radical
Hydrogen { Fixed and volatile oils
{ Of these only the carburets of
Metallic substances Carburets of metals { iron and zinc are known, and
{ were formerly called Plumbago.
Alkalies and earths Carburet of potash, &c. Unknown.
SECT. X.--_Observations upon Charcoal, and its Combinations with Simple
Substances._
As charcoal has not been hitherto decomposed, it must, in the present
state of our knowledge, be considered as a simple substance. By modern
experiments it appears to exist ready formed in vegetables; and I have
already remarked, that, in these, it is combined with hydrogen,
sometimes with azote and phosphorus, forming compound radicals, which
may be changed into oxyds or acids according to their degree of
oxygenation.
To obtain the charcoal contained in vegetable or animal substances, we
subject them to the action of fire, at first moderate, and afterwards
very strong, on purpose to drive off the last portions of water, which
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