DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.19574#0424
390 G L A
of Glafs lay a layer of the powder fomewhat thicker than the
former.
Then cover the furnace with its fhrowds of earth, joining and
luting them well together all round with the beft lute, fo that it
may admit of no refpiration, but through the fire-holes or the
opening of the furnace ; while you draw out the proofs for trials,
by fome called watches, which are bits of broken Glafs painted
with the colours, and put in purely for the purpofe of taking out
and examining how the work goes on.
Having thus ordered the furnace, and the lute being well dri-
ed, begin to heat it gently with fome charcoal on the outfide of
the furnace at the entrance, and fo proceed by degrees, and very
Jeifurely heightening it, left itfhould break the Glafs, or fpoil the
paint.
Continue this for two hours, then thruft the fire in further,
and let i< iemain there for an hour, putting it in by little and lit-
tle under the ftove, where let it ftand two hours longer; then in-
creafe the fire by degrees for two hours, and fo continue to apply
fuel till the furnace be lull of charcoal, and you perceive the flame
to convey itfelf through every hole of the cover; keep it thus
violent for three or four hours, fhutting the door of the furnace.
You muft be very cautious and careful, during the whole work
from the firft two hours, that the fire remains at the entrance.
From time to time you muft draw out fome of the pieces of
Glafs that you put into the ftove for trials or watches, to fee if the
colours be melted and the yellow be qualified. You may per-
ceive how the work gees on by the fparkling of the iron bars un-
der the ftove.
Asfoon as you find the colours almoft done, improve the fire
with fome very fmall billets of dry wood; thefe muft be very
fmall that they may be put in the more eafily, fmoke the lefs,
and to make the flame inviron, reverberate over and round about
the ftove, which muft be continued till the work is finifhed,
which will be in twelve or fourteen hours ; then let the fire go
out, and the work cool of itfelf; then it will be finifhed, and
take it out, or elfe it would foon burn the colours and break the
Glaffes.
Glass porcelain, the name given by many to a modern in-
vention of imitating the China ware with Glafs.
The method given by Mr. Reaumur, who was the firft who
carried that attempt to any degree of perfection, is delivered by
that gentleman, in the memoirs of the Academy of Sciences of
Paris, to this effect:
The mixing Glafs, reduced to powder, with other lefs eafy
vitrifiable fubftances, for the forming a pafte, to be afterwards
mace into a fort of porcelain, has been a contrivance lorg prac-
tUe4^
of Glafs lay a layer of the powder fomewhat thicker than the
former.
Then cover the furnace with its fhrowds of earth, joining and
luting them well together all round with the beft lute, fo that it
may admit of no refpiration, but through the fire-holes or the
opening of the furnace ; while you draw out the proofs for trials,
by fome called watches, which are bits of broken Glafs painted
with the colours, and put in purely for the purpofe of taking out
and examining how the work goes on.
Having thus ordered the furnace, and the lute being well dri-
ed, begin to heat it gently with fome charcoal on the outfide of
the furnace at the entrance, and fo proceed by degrees, and very
Jeifurely heightening it, left itfhould break the Glafs, or fpoil the
paint.
Continue this for two hours, then thruft the fire in further,
and let i< iemain there for an hour, putting it in by little and lit-
tle under the ftove, where let it ftand two hours longer; then in-
creafe the fire by degrees for two hours, and fo continue to apply
fuel till the furnace be lull of charcoal, and you perceive the flame
to convey itfelf through every hole of the cover; keep it thus
violent for three or four hours, fhutting the door of the furnace.
You muft be very cautious and careful, during the whole work
from the firft two hours, that the fire remains at the entrance.
From time to time you muft draw out fome of the pieces of
Glafs that you put into the ftove for trials or watches, to fee if the
colours be melted and the yellow be qualified. You may per-
ceive how the work gees on by the fparkling of the iron bars un-
der the ftove.
Asfoon as you find the colours almoft done, improve the fire
with fome very fmall billets of dry wood; thefe muft be very
fmall that they may be put in the more eafily, fmoke the lefs,
and to make the flame inviron, reverberate over and round about
the ftove, which muft be continued till the work is finifhed,
which will be in twelve or fourteen hours ; then let the fire go
out, and the work cool of itfelf; then it will be finifhed, and
take it out, or elfe it would foon burn the colours and break the
Glaffes.
Glass porcelain, the name given by many to a modern in-
vention of imitating the China ware with Glafs.
The method given by Mr. Reaumur, who was the firft who
carried that attempt to any degree of perfection, is delivered by
that gentleman, in the memoirs of the Academy of Sciences of
Paris, to this effect:
The mixing Glafs, reduced to powder, with other lefs eafy
vitrifiable fubftances, for the forming a pafte, to be afterwards
mace into a fort of porcelain, has been a contrivance lorg prac-
tUe4^