The Sincerely Discovered Art of Assaying and Refining of the Venetians

when they are knocked into it, one must put a little Klåre clarifier/coating in it, which one makes from the prongs of stags' horns, also burnt, and rubbed off on a stone like a paint and dried, painted on the bottom so that the grains run off smoothly.

The powder from burnt calves' heads also gives good cupel-clarifier.

Do you wish to test silver now?

Then you must first set the cupels in the testing-furnace under a muffle, and make a fire upon it, and let it get hot enough so that they are white in color; then they are hot enough. In the time that the cupels are getting hot, cut the test sample according to the whole mark Unit of weight for assaying. while you wait, so that it is equal in weight, and put it in a small letter A folded paper packet.. Then take 1 lot of lead, and set that into the cupels. If it is as good as the mentioned groschen A silver coin., then take only one lot of lead to a mark, and when the lead has melted on the cupel so that it does not jump, then set the silver also into it onto the lead, and let it go off finely together. When it has gone off, then take the grain The final metallic bead. out of the cupel, see if dirt hangs to it, and if it is found so, then take a pair of small pliers and drive it together with them, so the dirt falls into it. Then take the grain and weigh it on the balance; how much it weighs, that much a mark of fine silver holds.