Barrow, John [Editor]
Dictionarium Polygraphicum: Or, The Whole Body of Arts Regularly Digested: Illustrated with Fifty-six Copper-Plates. In Two Volumes (Band 2) — London, 1758

Page: 361
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ULT 361

To make a liquid for moijlening and grinding the powder withal,
l£c. For moiftening and grinding your aforefaid powder of the
ftone, take a pound and an half of running water, and put this
into a new earthen pot; add to it an egg-fhell full of raw honey,
boil it until it have no more fcum ; take the pot off, and keep
this hydromel, or liquid, in bottles forufe.

This done, take four fcruples of the beft gum dragon, grind
it on your marble, with fome of the hydromel, and then put it
into a glafs ; add thereto as much hydromel as you find conve-
nient to bring it to a violet colour, fo cover it, and preferve it
for ufe. This liquid is good for your powder of lapis lazuli ; if
the colour be too violet, add the lefs hereof; if otherwife, the
more, as your judgment or experience {hall direcc.

Put half a pound of powder at a time into a fmall porphyry
or marble veflel, the larger the mortar the worfe ; for you will
lofe more, and be longer a grinding ; pour leifurely by little and
little thereon fome of your violet liquid, grind thefe together
for a full hour, ft ill wetting it; you may ufe three or four ounces
of liquid to the half pound of powder,- and you will have it very
good ; you mult take care of grinding it too long, for then it will
lofe its colour.

When it is thus ground, dry it on a marble or Sat ftone,
where the fun does not come at all ; cover it well to preferve it
from duft ; when it is dry, it will powder eafily between your
fingers, if it be rightly done ; if fo, let it alone on the marble,
but if it be clammy, or ftick, take it off, for it has ftill fome
un&uofity of the honey in it, which muft be cleanfed away by
a cement.

Your lapis being thus dry, wafh it well before you put it to
the cement, for which you muft ufe a glazed earthen bafon,
round above like a barber's, and well glazed within; put your
lapis therein, and pour thereon fome of the mild lixivium here-
after mentioned, as much as will rife above the furface four
inches; wafh the lapis very well with your hands, and then let it
fettle, and it will precipitate. The liquid being cleared again,
decant it into a large copper or earthen vefTel, then let the lapis
dry in a fhade in the fame veflel it was wafhed in, and fpread it
afterwards on the flat marble or porphyry, and there let it lie urir
til quite dry : Thus it is prepared for mixing with the cement,
of which we will give the preparation hereafter.

To prepare a mild andftrong lixivium for lapis la%u}l. To make
thefe lixiviums, take ten handfuls of vine ftalk afhes well fearced y
put this into a large veflel that will hold thirty pounds of water,
with a faucet at bottom ; prefs the afhes very well- and put to
them twenty pounds of warm water. When it is funk to the
bottom, open thefaucet? fo as it may only drop into an earthen

veflel $
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