Description of the Most Principal Mineral Ores

that you can then use to make the back of the muffle. This must all happen over the small block, and be smoothed nicely with a damp hand. When the muffle has been smoothed over the small block, let it stand for an hour or three, so that the clay becomes a little harsh or hard-set. Then cut open the muffle, as you want to have it cut open on the sides and back, and let it stand even longer; then it goes quite readily off the small block. Some, when they have smeared the small block with the lard, strew it with subtle sand or ash, then the muffle also goes off soon. But so that one can prepare many muffles quickly together, let more than one of the wooden small blocks be made; while one is standing a little and drying out, all the while others become ready.

How one should smooth and prepare the clay bottom plates.

But for making the bottom plates, one has frames of wood, in the width as the bottom plates should be thick and wide; those one smears full with the prepared clay; they dry then soon so that they go out easily, or cut a plate from a large piece of clay with a thin wire, as thick as one wants to have it, and form it further as large as it should be.

On the drying and burning of the clay equipment for assaying.

These thusly prepared shards, muffles, bottom plates, and crucibles must dry very well, and then be burned in a brick or potter's kiln. Although the muffles and bottom plates can also be used raw and unburned in the assay furnaces, only one must act gently with the firing of the assay furnace, and let the fire start first from above downwards, so they remain whole; otherwise everything will burst. With this, you have:

A small decorative floral ornament (fleuron).