
n
~~~~~~~~~~~~~~~101r~~~~~~~~~~~~~~~


again very well, then add in iii ℥ of
minium, & pestle well again all together, & put
it in the crucible, which you will cover with an appropriate
tile, a bit thick, in order that heat reverberates better
there. Then set it on the grill of your furnace,
having put under a few thick rounded squares. Next, fill your
furnace to the opening with charcoal, so that it will
be heaped, and leave it glowing, and always maintain the heat evenly
without letting the charcoal decrease. And for this effect,
always make so that the furnace is heaped & full of
charcoal, and maintain it thus for one day.
The first experience that I made thus, it only returned a yellow mass,
as is only vitrified minium, & some grains of
gold in a mass at the bottom. Try soldered gold
and accompanied with antimony.



If you need greater heat, plie put on the edge of
the opening of the glowing furnacetiles, one against
the other, for making the heat reverberate.


Topaz

The same dose is observed for all gemstones, namely
one weight of calcined pebbles on three of
minium, pestling all separately in a
copper mortar for emerald, & in an
iron mortar for making topaz or amber
color, with pestles identical to the mortars. The
emerald & the topaz are of the same heat, & for an
hour & a half on the fire, for they could burn.
The rubyen wants more time & more fire
& colored with gold leaf. I believe that pumice stone
or firestone for the ruby would be better. See the
enamels. Try also mixing, in place of pebbles, pieces of
colored glass or enamels. If the mass is not colored
enough, pestle it more in the iron mortar.

Slightly burnt tartar mixed among this makes beautiful yellow,
but one scarcely needs much. The arene also makes it
more yellow.


Salt for melting

Mix saltpeter & common salt and melt them together
& cast on melted copper or ch in a
bain, & it purifies & makes it run marvellously. First,
one ought to decrepitate the common salt, that is to say
holding it over a good fire until it no longer crackles or, to melt it
better, in an four à vent. And throw it neatly on
marble, then crush it & grind it very finely, then
put it in a crucible on as muchsaltpeter &
let it boil, & mix them together until



It cleans & purifies metal well.

