fixed alkaline salt, prepared chiefly in Germany, Russia, and Poland, by melting the salts out of the ashes of burned wood, and, having reduced them to dryness, evaporating the moisture, and calcining them for a considerable time in a furnace moderately heated. The goodness of pearl-ashes may be ascertained by a uniform and white appearance; but they are nevertheless subject to a common adulteration, not easily distinguishable by the mere appearance, and which is done by the addition of common salt. Pearl-ashes are much used in the manufacture of glass, and need no preparation, except where very great transparency is required.