LU′PUS. In pathology, a disease affecting the skin, remarkable for eating away the parts which it attacks with extreme rapidity. It is generally confined to the face, and commences with small, spreading ulcerations, which become more or less concealed beneath bran-like scabs, and end in ragged ulcers, which gradually destroy the skin and muscular tissue to a considerable depth.
LUS′TRE. See Plumbago.
LUTE. Syn. Luting; Lutum, Cæmentum, L. A composition employed to secure the joints of chemical vessels, or as a covering to protect them from the violence of the fire.
Prep. 1. Linseed meal, either alone or mixed with an equal weight of whiting, and made into a stiff paste with water. It soon becomes very hard and tough.
2. Ground almond cake, from which the oil has been pressed, mixed up as the last. Both the above are much used for stills, retorts, and other vessels that are not exposed to a heat higher than about 320° Fahr. They are capable of resisting the action of the fumes of volatile oils, spirits, weak acids, &c., for some time.
3. Fresh-slaked lime made into a paste with strained bullock’s blood or size. As the last.
4. Plaster of Paris made into a paste with water, and at once applied. It bears a nearly
red heat, but becomes rather porous and friable.
5. Powdered clay or whiting made into putty with water and boiled linseed oil. This is commonly known as ‘fat lute.’
6. A mixture of powdered clay and ground bricks, made up with water or a solution of borax. For joining crucibles, &c., which are to be exposed to a strong heat.