Lute. A composition employed to se-cure the joints of chemical vessels, or as a covering to protect them from the violence of the fire. For the joints of vessels, as stills, etc., not exposed to a heat much higher than 212° Fahr., linseed meal, either alone or mixed with an equal weight of whiting, and made into a stiff paste with water, may be employed. Ground almond cake, from which the oil has been pressed, may also be used for the same purpose. For the joints of small vessels, as tubes, etc., especially of glass or earthenware, small rings of India rubber slipped over and tied above and below the joint, are very convenient substitutes for lutes, and have the advantage of lasting a long time, and bearing uninjured the heat at ■which oil of vitriol boils.

2264. Lute for Stills

2264.    Lute for Stills. A very useful lute is formed by beating the white of an egg thoroughly with an equal quantity of water, and mixing it with some slacked lime in the state of fine powder, so as to form a thin paste. This must be spread immediately on strips of muslin, and applied to the cracks or joints intended to be luted. It soon hardens, adheres strongly, and will bear a heat approaching to redness without injury. A leak in this lute is readily stopped by the application of a fresh portion. Solution of glue, or any liquid albuminous matter, may be used in place of the white of eggs.

2265. Lemery's Lute for Stills or Retorts

2265.    Lemery's Lute for Stills or Retorts. Lemery used the following lute for stopping retorts, etc.: Fine flour and fine lime, of each 1 ounce; potter's earth, 1/2 ounce; make a moist paste of these with white of egg, well beaten up with a little water; this will be found to stop exceedingly close.

2266. Boyle's Lute for Retorts, etc.

2266.    Boyle's Lute for Retorts, etc.. Boyle recommends, on experience, the following for the same purpose: Some good fine quicklime and scrapings of cheese, pounded in a mortar, with as much water as will bring the mixture to soft paste; then spread on a piece of linen rag, and apply it as occasion requires.

2267. Useful Lute

2267.    Useful Lute. A useful lute is made by spreading a solution of glue on strips of cloth, and coating them, after they are applied, with drying oil.

2268. Lute for Joining Crucibles

2268.     Lute for Joining Crucibles. For joining crucibles to be exposed to a strong heat, a mixture of fine clay and ground bricks, mixed up with water, or preferably with a solution of borax, answers well for most purposes.

2269. Fire Lute

2269.    Fire Lute. As a coating for vessels, to preserve them from injury from exposure to the fire, nothing is better than a mixture of ordinary pipe-clay and horse dung, made into a paste with water. This composition is used by the pipe-makers, and will stand unharmed the extreme heat of their kiln for 24 hours. It is applied by spreading it on paper.

2270. Lute to Protect Glass Vessels

2270.    Lute to Protect Glass Vessels. The following composition will enable glass vessels to sustain an incredible degree of heat: Take fragments of porcelain, pulverize, and sift them well, and add an equal quantity of fine clay, previously softened with as much of a saturated solution of muriate of soda as is requisite to give the whole a proper consistence. Apply a thin and uniform coat of this composition to the glass vessels, and allow it to dry slowly before they are put into the fire.