Abstract: A process for polymerizing ethylene or copolymerizing ethylene with an .alpha.-olefin in the presence of a catalyst comprising: (A) a solid catalyst ingredient obtained by contacting (1) a solid reaction product prepared by reacting (a) a reaction product of an aluminum trihalide with an organic compound containing an Si--O bond and/or an ether compound and (b) a magnesium alcoholate with (2) a tetravalent titanium compound containing at least one halogen atom or further (3) an electron donor compound, and (B) an organo-aluminum compound.

Abstract: A flare monitoring apparatus for detecting the generation of black smoke in a flare, the excessiveness of a flare and extinguishment of a flare based on the ratio and/or difference between an emissive power of infrared radiation emitted from a flare at a wave length at which a peak of the emissive power due to a resonance infrared radiation of a specified gas contained in a flue gas exists and an emissive power of infrared radiation emitted from the flare at another wave length at which a peak of the emissive power due to a resonance radiation does not exist. The apparatus produces an alarm and automatically controls the state of the flare upon the detection of the abnormality of the flare.