Abstract: A magnetic detector comprises a magnetic recording medium in which a magnetic signal of wavelength .lambda. generated by two types of opposing magnetic poles which are repeated at constant intervals is recorded and a magnetic resistance element that is arranged opposite to the magnetic recording medium and changes its resistivity value according to the change in a magnetic field. The magnetic resistance element is comprised of first and second current paths constructed of a plurality of magnetic resistance strips. The first current path and the second current path are connected in series with each other. Each magnetic strip of the first current path is arranged parallel to that of the second current path at an interval of .lambda./4 to form a plurality of magnetic resistance strip sets. Centers of the magnetic strip sets are spaced by 3n.lambda./4 from each other, where n is an integer of 1 or greater.

Abstract: Lubricating oil composition for use with sintered porous bearings includes a poly-.alpha.-olefin hydride or ethylene-.alpha.-olefin copolymer hydride containing base oil to which at least one additive selected from the group consisting of zinc dialkyl dithiophosphate, molybdenum dialkyl dithiocarbide, molybdenum dialkyl dithiophosphate and a sulfur-phosphorus containing extreme pressure additive is added in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the base oil.