The pottery is moulded and fire-baked.
Concrete is readily procured and easily moulded into shape.
The former includes electrodes, lamp carbons, &c. Coke, or some other form of amorphous carbon, is mixed with a little tar, and the required article moulded in a press or by a die.
The plate when passed as flawless was cut into the desired form and moulded as far as possible into shape, the edges where necessary being soldered.
It has thus the immense advantage over natural stone that it can be easily moulded while wet to any desired shape or size.