BEARING

direction of ship with respect to points of compa , or b. of any mark relative to fore-and-aft line of ship (naut.); part of building resting on support, as beam upon wall, or span between supports (arch.); support which permits moving part of machine to revolve or slide (mech.). The simplest b. consists of block and cap containing two semicylindrical ‘bra es’ between which the shaft journal rests, and lubrication contrivance to interpose film of oil between journal and bra es. In thrust block b., the journal is provided with collars fitting into circumferential grooves in the bra es, to prevent longitudinal shifting of shaft (e.g.) of propeller shaft. Footstep or pivot b. supports the entire weight of vertical shaft and must, therefore, be provided with special lubricating apparatus. Friction is considerably reduced by fitting roller or ball b., which are extensively used in cycles and motor-cars.