DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.19574#0405
%fi G L A
faltwort, from its faline tafte ; and alfo glafs-weed, from the ufe
made of its allies in making Glafs.
To get the fait from this polverine, they pulverife and fift it
very fine ; then boil it in a brafs copper, with fair water and
tartar, till a third part of the water is confumed, taking care to
ftir it from time to time.
Then, filling up the copper with frefh'water, they boil it a
fecond time till half be confumed ; when this has been done,
there remains a ley impregnated with fait. To get the leys from
the fait, they boil them, till the fait fhoots at the top, which
they fcum off as it rifes ; an hundred pounds of afhes this way
ufually yield eighty or ninety of fait.
When the fait is dry, they beat it grofly, and put it into a fur-
nace to dry it farther with a gentle heat. When it has been fuf-
ficiently dried, they pound and fift it very fine, and lay it by to
make frit.
But you muff alfo take notice, that, befide9 the afhes of kali,
thofe of fern will alfo yield a fait, which will make excellent
Glafs, in nothing inferior to that of polverine.
The method of preparing the afhes of fern is the fame as that
of thofe of kali.
The afhes alfo of the coo's and {talks of beans, as alfo of cole-
Worts, bramble-bufh, millet-ftalks, rufhes, and many other
plants, may be ufed for the fame purpofe.
2. As for {tone, which is the fecond ingredient in Glafs, the
belt of which is that which will melt, is white and tranfparent.
This fort of {tone is found chiefly in Italy and is called tarfo, and
is a kind of marble; the next is quocoli or cuogele, a fort of peb-
bles, found at the bottoms of rivers.
Indeed nothing makes finer and clearer Glafs than flint; but
the charge of preparing it deters Glafs-makers from ufing it ;
the preparation necefTary for {tone is to calcine, powder, and
fearce it.
Anthony Neri obferves, that all white tranfparent {tones,
which will not burn to lime, are fit to make Glafs ; and that all
{tones which will ftrike fire with fteel, are fit for making Glafs.
But Dr. Merret objects againft this laft rule as not holding uni-
versally.
Where Glafs-makers cannot eafily have proper {tone, they
make ufe of fand, the beft for the ufe is that which is white and
fine ; for green Glafs, that which is harder and more gritty.
The preparation that it needs is only wafhing it well.
Maidftone in Kent furnifhes our Glafs-houfes with white fand
for their cryftal Glafs, and with the coarfer for green Glafs.
The method of making white and cryftal Glass. There are
three forts of furnaces ufed in making Glafs; the one to prepare
2 the
faltwort, from its faline tafte ; and alfo glafs-weed, from the ufe
made of its allies in making Glafs.
To get the fait from this polverine, they pulverife and fift it
very fine ; then boil it in a brafs copper, with fair water and
tartar, till a third part of the water is confumed, taking care to
ftir it from time to time.
Then, filling up the copper with frefh'water, they boil it a
fecond time till half be confumed ; when this has been done,
there remains a ley impregnated with fait. To get the leys from
the fait, they boil them, till the fait fhoots at the top, which
they fcum off as it rifes ; an hundred pounds of afhes this way
ufually yield eighty or ninety of fait.
When the fait is dry, they beat it grofly, and put it into a fur-
nace to dry it farther with a gentle heat. When it has been fuf-
ficiently dried, they pound and fift it very fine, and lay it by to
make frit.
But you muff alfo take notice, that, befide9 the afhes of kali,
thofe of fern will alfo yield a fait, which will make excellent
Glafs, in nothing inferior to that of polverine.
The method of preparing the afhes of fern is the fame as that
of thofe of kali.
The afhes alfo of the coo's and {talks of beans, as alfo of cole-
Worts, bramble-bufh, millet-ftalks, rufhes, and many other
plants, may be ufed for the fame purpofe.
2. As for {tone, which is the fecond ingredient in Glafs, the
belt of which is that which will melt, is white and tranfparent.
This fort of {tone is found chiefly in Italy and is called tarfo, and
is a kind of marble; the next is quocoli or cuogele, a fort of peb-
bles, found at the bottoms of rivers.
Indeed nothing makes finer and clearer Glafs than flint; but
the charge of preparing it deters Glafs-makers from ufing it ;
the preparation necefTary for {tone is to calcine, powder, and
fearce it.
Anthony Neri obferves, that all white tranfparent {tones,
which will not burn to lime, are fit to make Glafs ; and that all
{tones which will ftrike fire with fteel, are fit for making Glafs.
But Dr. Merret objects againft this laft rule as not holding uni-
versally.
Where Glafs-makers cannot eafily have proper {tone, they
make ufe of fand, the beft for the ufe is that which is white and
fine ; for green Glafs, that which is harder and more gritty.
The preparation that it needs is only wafhing it well.
Maidftone in Kent furnifhes our Glafs-houfes with white fand
for their cryftal Glafs, and with the coarfer for green Glafs.
The method of making white and cryftal Glass. There are
three forts of furnaces ufed in making Glafs; the one to prepare
2 the