substance used for making vessels or apparatus air-tight, by closing the apertures of their joints, or for coating, so as to enable them to bear a higher temperature, or for repairing a fracture. Clay is the basis of many lutes; whence the term from lutum, clay. Among the principal lutes are Stourbridge clay, in fine powder, made into a paste with water; Windsor loam, a natural mixture of clay and sand; Willie's lute, a thin paste made of a solution of borax in boiling water, with slaked lime. Mixtures of borax and clay also form useful lutes. What is called fat lute, is a mixture of pipe-clay with drying linseed-oil. Caustic lime, furnishes, by admixture with other bodies, a variety of lutes. A mixture of lime and white of egg, or glue, forms a powerful cement. Iron cement (described under Gas-Ligarr) is useful for making joints tight, as is also white-lead, ground