The Da Vinci Notebooks
On the coining of medals (727. 728).The incombustible growth of soot on wicks reduced to powder, burnt tin and all the metals, alum, isinglass, smoke from a brass forge, each ingredient to be moistened, with aqua vitae or malmsey or strong malt vinegar, white wine or distilled extract of turpentine, or oil; but there should be little moisture, and cast in moulds. 349
18:349 : The meaning of scagliuolo in this passage is doubtful.