. . .water when in a state of ebullition; and once boiling in this manner is more effectual than a dozen washings in hot water.

Much depends on the purity of the water used in the process. If it be hard pump water, the selenites with which it is impregnated will be decompounded, and[Pg 10] the calcareous earth be deposited, after boiling; which mixing with the Magnesia will render it impure, gritty and discoloured. Rain water collected free from impurities, or clear river water, are most eligible; but if the situation of the operator does not permit him to procure these in a proper state, he should either use distilled water, which has been kept till the empyreuma is gone off, or at least such pump water as is free from any calcareous or saline impregnation. When poured on the Magnesia, it should be strained through a thick linen cloth, so as to intercept any accidental impurities which it may acquire in heating.

The drying should be performed with expedition. . . Read More