This reflector terminates above in a dome, in whose center is placed a refractory clay box.

The muffles are made of refractory clay.

This is placed in a second larger crucible of refractory clay, and the intervening space filled with lampblack tightly packed.

The sides of the crucibles are covered with a thin layer of refractory clay, and their bottoms have a spherical concavity to hold the bloom.

A very elaborate display of kaolin-plastic, vitrifying, and refractory clays-wasmade.