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474
§ i._Of the Porcelain Earth, or Kaolin.
Kaolin is a very argillaceous earth, serving for the base of
the different substances which enter into the composition of
the paste proper for making the teeth.
It has the property of separating itself in water, and of
making a very unctuous paste, which can be moulded into
the most delicate objects, and gives them, at the same time,
the advantage of preserving the shapes with which they are
stamped.
It acquires, by baking, an extreme hardness and a smooth
surface ; nor will the most penetrating liquids act upon it.
This earth, employed alone, shrinks in the fire, and sup-
ports with difficulty the sudden passage from heat to cold ;
but this inconvenience may be remedied, by mixing a small
portion of the earth of Vanvres, as well as the oxides and
metals in fine filings, which may be seen in the different for-
mulas.
The fluid caloric is then more equally circulated through
the mass, and the article is heated to a higher degree with-
out cracking, which is indispensable in the soldering incor-
ruptible teeth.
Kaolin may be obtained from all the manufacturers of por-
celain, and particularly from Mad. Cremiere, Menie Montant-
street, No. 48.
§ ii. Of the Earth of Vanvres.
The earth of Vanvres is very argillaceous ; it is employed
m the manufactories for making the circles on which porce-
lain is baked.
After being baked, it is of a shining rusty colour ; supports
474
§ i._Of the Porcelain Earth, or Kaolin.
Kaolin is a very argillaceous earth, serving for the base of
the different substances which enter into the composition of
the paste proper for making the teeth.
It has the property of separating itself in water, and of
making a very unctuous paste, which can be moulded into
the most delicate objects, and gives them, at the same time,
the advantage of preserving the shapes with which they are
stamped.
It acquires, by baking, an extreme hardness and a smooth
surface ; nor will the most penetrating liquids act upon it.
This earth, employed alone, shrinks in the fire, and sup-
ports with difficulty the sudden passage from heat to cold ;
but this inconvenience may be remedied, by mixing a small
portion of the earth of Vanvres, as well as the oxides and
metals in fine filings, which may be seen in the different for-
mulas.
The fluid caloric is then more equally circulated through
the mass, and the article is heated to a higher degree with-
out cracking, which is indispensable in the soldering incor-
ruptible teeth.
Kaolin may be obtained from all the manufacturers of por-
celain, and particularly from Mad. Cremiere, Menie Montant-
street, No. 48.
§ ii. Of the Earth of Vanvres.
The earth of Vanvres is very argillaceous ; it is employed
m the manufactories for making the circles on which porce-
lain is baked.
After being baked, it is of a shining rusty colour ; supports
