calcareous earth of the bones into a sulphat of lime, and the phosphoric
acid remains free in the liquor. The liquid is decanted off, and the
residuum washed with boiling water; this water which has been used to
wash out the adhering acid is joined with what was before decanted off,
and the whole is gradually evaporated; the dissolved sulphat of lime
cristallizes in form of silky threads, which are removed, and by
continuing the evaporation we procure the phosphoric acid under the
appearance of a white pellucid glass. When this is powdered, and mixed
with one third its weight of charcoal, we procure very pure phosphorus
by sublimation. The phosphoric acid, as procured by the above process,
is never so pure as that obtained by oxygenating pure phosphorus either
by combustion or by means of nitric acid; wherefore this latter should
always be employed in experiments of research.

Phosphorus is found in almost all animal substances, and in some plants
which give a kind of animal analysis. In all these it is usually
combined with charcoal, hydrogen, and azote, forming very compound
radicals, which are, for the most part, in the state of oxyds by a first
degree of union with oxygen. The discovery of Mr Hassenfratz, of
phosphorus being contained in charcoal, gives reason to suspect that it
is more common in the vegetable kingdom than has generally been
supposed: It is certain, that, by proper processes, it may be procured
from every individual of some of the families of plants.

As no experiment has hitherto given reason to suspect that phosphorus is
a compound body, I have arranged it with the simple or elementary
substances. It takes fire at the temperature of 32 deg. (104 deg.) 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 e