161v - - - - - Crocum ferri
It can be made quickly if you put filings, well cleaned and washed in an iron drum to the height of two fingers, and cover it, and redden in a reverberatory furnace, having washed it in good vinegar for a whole day. And it will be very well burnt and clean, mixed and crushed on a marble slab. Having been well crushed and when well mixed, the vinegar will corrode it easily and will redden it quickly and bind it. Wet it with the strongest one you can find and burn it after. And after three or four wettings and burnings it will be ready. This one will be the color of columbine and is considered firmer for casting than the one that is redder and more beautiful in color, done with rusty filings and has more color in it. Some burn the filings many times on a shovel of red iron, watering each time with vinegar.