FRICTION

The act of rubbing the surface of one body against that of another; attrition; in hygiene, the act of rubbing the body with the hand, with flannel, or with a brush etc., to excite the skin to healthy action.

The resistance which a body meets with from the surface on which it moves. It may be resistance to sliding motion, or to rolling motion.

A clashing between two persons or parties in opinions or work; a disagreement tending to prevent or retard progress. Angle of friction (Mech.), the angle which a plane onwhich a body is lying makes with a horizontal plane,when the hody is just ready to slide dewn the plane.

A device in which a piece on one shaft or pulley is so forcibly pressed against a piece on another shaft that the two will revolve together; as, in the illustration, the cone a on one shaft, when thrust forcibly into the corresponding hollow cone b on the other shaft, compels the shafts to rotate together, by the hold the friction of the conical surfaces gives. (b) A toothed clutch, one member of which, instead of being made fast on its shaft, is held by friction and can turn, by slipping, under excessive strain or in starting. -- Friction drop hammer, one in which the hammer is raised for striking by the friction of revolving rollers which nip the hammer rod. -- Friction gear. See Frictional gearing, under Frictional. -- Friction machine, an electrical machine, generating electricity by friction. -- Friction meter, an instrument for measuring friction, as in testing lubricants. -- Friction powder, Friction composition, a composition of chlorate of potassium, antimony, sulphide, etc, which readily ignites by friction. -- Friction primer, Friction tube, a tube used for firing cannon by means of the friction of a roughened wire in the friction powder or composition with which the tube is filled -- Friction wheel (Mach.), one of the wheels in frictional gearing. See under Frictional.