Abstract: To prevent attack on electrodes (4, 5) within a discharge vessel (2) by an ionizable metal halide fill, due to spurious or free oxygen arising within the lamp during operation thereof, which oxygen combines with the metal of the electrodes, and is then dissociated in the arc and re-deposited at the hottest part of the electrode, an oxygen removing getter material is introduced into the discharge vessel. Spurious oxygen arises due to emission of oxygen from the glass wall of the discharge vessel, typically quartz glass, and unavoidable contaminants of the fill substance. The getter material is, preferably, phosphorus, boron or aluminum, a halide of the foregoing, a tungsten boron compound, a tin phosphorus compound, or scandium or a rare earth. If the getter is a halide, iodine, bromine or chloride are suitable. The getter may be introduced in quantities of between 0.05 to 0.6%, depending on the getter substances and the fill composition.

Abstract: A carburetor is provided with a separate idle air/fuel system containing an idle fuel metering jet or orifice; and an idle fuel tube connected to an induction passage discharge port downstream of the throttle valve, the idle fuel tube being surrounded or enclosed near the discharge end by an air well connected to a main air bleed, this portion of the idle tube having air bleed holes for mixing air with the fuel to provide acceptable driveability during idle speed operation, the diameter of the holes being mathematically calculatable to vary in a direct relation to the size of the idle metering jet and in an inverse relation to the diameter of the idle air well tube, to provide an essentially constant air/fuel ratio to the idle mixture flow upon changes in either the idle jet size or the idle tube size.