Making and Knowing
A minimal edition of BnF Ms Fr 640

[TOC] | [diplomatic]

- - - - - folio image: 100v - - - - -


Take white pebbles that are found along rivers & along gravel banks, & paths and that are somewhat transparent. If they are perfectly transparent, & it will be better. If not, use the best & whitest ones that you can find. Calcine them three or 4 times in your four à vent & quench them in water or vinegar. Then, take a of them and pound them in a completely pure copper mortar, & with a pestle of pure copper, and grind them until they become very fine & soft powder; this is a sign that they have taken enough of the substance ofcopper to give them greenness. Then in your of pebbles, add in three of good minium, unadulterated by brick & something else, and strongly pound everything together again in a bronze mortar. And in all of this, add in a gros pour of sel de verre, & some & the common people put in sandever that they find it among the glassmakers or apothecaries. But alkali salt, as you know, is better.

at left middle margin

Emerald In this way, the vulgaire makes emeralds & casts them in sand. If you do not have a bronze mortar, crush avecqun mort in a cauldron of pure copper.

at left top margin

The cruciblesneed to be reheated before putting materials in, and need to be put in the forge or four à vent instead of making & increasing the fire. Figure Figure

at left middle margin

They are done in an hour & a half.

at left middle margin

A gros of salt in four of pebbles &minium. When one says: for , what is to be understood is: an of body & not of salts & minium.

For ruby take goldin leaves

Raise your stove by two tiles all around because more heat is needed to make rubies than emeralds. And take an of white, calcined pebbles, and put it in a glass mortar &, having roughly pounded it with the same kind of pestle, mix un grain in the weight of a grain of gold leaves of the kind used by painters for gilding, & crush.

at left bottom margin

Some say that mixing the gold with pebbles and saltpeter gives the color of a peach tree . at left bottom margin

Others say that the gold has to be cemented several times and then beat into leaves.