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477
§ vn. Of the Oxide of Manganese.
The oxide of manganese is used in the fabrication of in-
corruptible teeth, by nearly all the dentists who have been
engaged therein. M. Dubois Foucou himself, in his pam-
phlet recommends it, and it is in his work a principal auxiliary.
M. Chaptal, in his chemisty applied to the arts,* says that
in the glass manufactories it is used to change the col >ur of
glass, and for this reason, it is known by the name of soap
of the glass-makers. In another place he says it is used to give
glass a violet colour ; and again in another passage,! he pre-
scribes it for making a yellow-coloured enamel. Consider-
ing the different properties attributed to this oxide by M.
Chaptal, it appears to be a very convenient substance in
the fabrication of incorruptible teeth ; at least one would
think so, after having read what this learned chemist has said
about its properties.
In the mean time we would here observe, that after hav-
ing submitted the oxide of manganese to numberless trials,
we remain convinced it is less fit for this purpose when used
by itself ; being so extremely subject to change, that it seldom
or never produces twice the same tint ; it cannot be incorpo-
rated by itself in clay nor in enamel, and to make its colour-
ing principle a little more fixed, it is necessary to mix it with
otlicr oxides, for without that, we must renounce obtaining
from it the yellow colour, which it is pretended it gives, be-
cause so uncertain in result.
The oxides of manganese, of antimony, and of iron, were
the colourings I used for my first trials ; and I can say, with-
* Chimie appliquee aux arts, Tome III. page 385.
i Tome II. pa§c 256.
477
§ vn. Of the Oxide of Manganese.
The oxide of manganese is used in the fabrication of in-
corruptible teeth, by nearly all the dentists who have been
engaged therein. M. Dubois Foucou himself, in his pam-
phlet recommends it, and it is in his work a principal auxiliary.
M. Chaptal, in his chemisty applied to the arts,* says that
in the glass manufactories it is used to change the col >ur of
glass, and for this reason, it is known by the name of soap
of the glass-makers. In another place he says it is used to give
glass a violet colour ; and again in another passage,! he pre-
scribes it for making a yellow-coloured enamel. Consider-
ing the different properties attributed to this oxide by M.
Chaptal, it appears to be a very convenient substance in
the fabrication of incorruptible teeth ; at least one would
think so, after having read what this learned chemist has said
about its properties.
In the mean time we would here observe, that after hav-
ing submitted the oxide of manganese to numberless trials,
we remain convinced it is less fit for this purpose when used
by itself ; being so extremely subject to change, that it seldom
or never produces twice the same tint ; it cannot be incorpo-
rated by itself in clay nor in enamel, and to make its colour-
ing principle a little more fixed, it is necessary to mix it with
otlicr oxides, for without that, we must renounce obtaining
from it the yellow colour, which it is pretended it gives, be-
cause so uncertain in result.
The oxides of manganese, of antimony, and of iron, were
the colourings I used for my first trials ; and I can say, with-
* Chimie appliquee aux arts, Tome III. page 385.
i Tome II. pa§c 256.
