Making and Knowing
A minimal edition of BnF Ms Fr 640

[TOC] | [diplomatic]

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For casting

Asphaltum is, which is found in Germany, is the most excellent sand one can find for molding in a frame, because it is appropriate for silver & for gold, & the more you use it and the older it is, the better it is. One molds in it very thinly & finely.

Making gold run for casting

Because gold cools down very quickly, one ought to give it a mix when melted q it is well melted which maintains the heat. Sublimate softens it nicely. But, because it goes up in smoke, it does not continue to help. Therefore mix this composition when you want to cast: sal ammoniac, the best verdet that you can find, a little borax & saltpeter qui li. And this, by keeping it warm, it will come out neatly. Saltpeter clarifies it & p heats it. But the most important thing in this mixture is the verdet, which has to be good. This mixture softens the gold qui so much that it becomes treatable like lead, even fine gold.

For sand for molding flowers & leaves & delicate things, mix in well—ground raw plaster, brick & alum de plume.

To moisten sands, eau de vye is excellent, for it grinds the sand finely & evaporates que when one reheats the frames.

Sal ammoniac water is very good, is excellent for moistening sands, but for lots of water one only needs a little sal ammoniac.

A lump of iron, for lack of crocum ferri, is exce good for gold.

The snakes or lizards you want to mold should not be kept for a long time, for if they are alive, they get thin, and if they are dry il dead, they wither.

Plaster of Paris is as firm as stone & very good. When you will want to choose some for your sand, take it raw, the hardest possible & which does not make any powder. The transparent one and the one that thusly makes powder retracts, Ce which is not good for this work. A sign of the one that is close to perfection is that it is hard & made of lustrous grains nearing the shape of sugar. Finally, to mix some into the sand to cast gold, it is necessary that it endures the fire twice, & is reheated twice.

at left middle margin

+ When gold is very fine, it is so dry that it can hardly endure a hammer, but this mixture softens it like lead.