Magnesia Crucible: Strongly Calcined Magnesia Bound with Raw Magnesia and Baked at a Red Heat (Thorpe 1912)

A magnesia crucible is a pot of magnesia, a basic refractory. Thorpe's Dictionary of Applied Chemistry (1912) gives the recipe introduced by Caron: magnesia shrinks a great deal when heated, so it is first calcined hotter than it will ever be used, then bound with 15-30 per cent of raw, slightly calcined magnesia and 10-15 per cent of water, moulded, dried and baked at a red heat. He gives no calcining temperature, mould or size; those are unknown here. Source: Thorpe, Dictionary of Applied Chemistry vol. II (1912), CRUCIBLES, p. 170. Picture: that passage.