LUBRICANT, a substance inserted between moving contact parts of a machine for the purpose of reducing friction and preventing abrasion. The substances used as lubricants vary great ly with the use to which they are putó solids such as soapstone or graphite, used to lubricate surfaces subjected to high pressure and running at low speed are one extreme; a light oil such as castor oil, used for the high speed, high temperature airplane motor, is the other extreme. The requirements of a good lubricant are: low coefficient of friction, stability under high temperature (high flash point), as fluid a body as possible to fulfill the requirements, since a high viscosity means a high coefficient of friction, freedom of acids or other in jurious impurities which would react chemically with the metal of the bearing to which it was applied, and freedom from impurities which cause gumming.
Various lubricants, designed for special purposes, by mixing mineral, animal or vegetable oils, are on the market.
Among the methods of lubrication are direct application by hand; the gravity system, in which the oil flows through a pipe from a tank to the bearing by gravity; various mechanical systems in which the oil is circulated by means of a pump from a tank to the bearings, and frequently through a strainer back into the tank; and the splash system, in which some moving part of the motor splashes oil from a closed case over all bearing surfaces.
LUCANIA (111-ka'ni-5.), a province of ancient Italy, S. E. of Calabria, and bordering on the Gulf of Tarentum. It was inhabited by an Oscan people, and corresponds nearly to the present ince of Potenza and part of Salerno.