
~~~~~~~~~~~~~~~108v~~~~~~~~~~~~~~~


thus one mixes it & reducing it into
pb small stones, purging it of its
impurities. Then one puts it to cook neatly in a
potearthen vessel in
the furnace of those who make pots, and one
leaves it there until the pots are cooked. Next, one mixes it
again with essence of sal ammoniac & one grinds it very well,
and one empties the muddy & clean water in a separate
vessel. Again, one puts the same essence on top &
one grinds & again one puts the muddy water with the other.
And one does thusly, until it has passed everything. In this way, one
purges & purifies it, & one renders it very fine &
handleable. Having taken away the water, by tilting it or with a
sponge, one takes the residue and one dries it. Then,
moistening it with the above mentionned water, like one does with
the other eau sand, one uses it in
chassis, where, if it retracts, it is a sign that it
has not reheated enough & that one needs to reheat it further. This
one is appropriate for molding all metals, and especially
gold & silver, and the more it is used the better it
is. One needs to set aside the one in which you cast lead or
tin, for it would sour the gold you would cast.

Alum de plume should be reheated in a
chaulderoncrucible covered
with a tile in a strong flammecharcoal fire, so that the impurities, which could be there,
burns with it which does not burn. This is done either in the
goldsmith’s forge, surrounded with
bricks, or in a fourneau à vent with
foeu de fusion, so that the sable demeure asses
long tempscrucible remains red for a
quarter hour. This is done more to purify it
than for anything else. It becomes reddish on the surface & on the
inside it remains white & better dried out #

# After your alum de plume is cooled,
pestle it in a mortar, then grind it on the
marble, and it will be rendered in very fine wooly
filaments, which gives binding to the sand, without getting burned as
other things do, which is a fine invention. Pestle it in the
mortar, by dragging the pestle, for the flying dust
could enter your throat or land on your face, which
will give you reason to scratch yourself well. Put a little
every time in the mortar, to avoid the flying dust. It is
better to grind it thusly, in the mortar, dragging the
pestle, than on the marble,
car where c it spreads & in
the mortar, it collects on all sides. Render it very fine &
soft to the touch.

Clay,to make circles around molds, should
be very fat & handleable, and serves only to make the surrounding of
the molds. Thus, one needs only choose it well fat, and beat
very well & moisten it moderately with some water & keep
it in a pit or in a terrine and make numerous
holes with a stick in it, which fill with water, in
order to keep always fresh & soft, so that it is always ready to use
when needed.

