wear dangerously thin at the back, where, should they suddenly burst, nearly the whole contents would be lost in the furnace. Glass-makers patch up pots in the crown or in front, and occasionally at the bottom. A pot split dangerously in the front is preserved from leakage for several weeks by exposing the cracked part to the atmospheric air, (first taking away the temporary brickwork in front,) which chills and hardens the metal as it exudes, until it is stopped by its own leakage. Should the temperature of the atmosphere be insufficient to check the leakage, cold water must be thrown upon the fissure; or a piece of black Glass or common bottle metal softened by heat, and plastered upon the opening. A crack in the bottom may sometimes be prevented from leakage by lifting the pot and contents by leverage upon fire-bricks, and exposing the bottom to air or water, as before described; but the latter seldom answers, although a broken-fronted pot may last many weeks, and fuse metal moderately well.