Abstract: A vehicle having an engine with a carburetor supplying fuel and having a variably positionable throttle valve, has vacuum responsive motor means operatively connected to the throttle valve for at times closing the throttle valve so as to govern the maximum speed of the engine associated with the vehicle; a variably positionable vent or valving means controls the amount of ambient air being bled into the vacuum responsive motor means in order to thereby determine when such vacuum responsive motor means will be effective to control the position of the throttle valve; and electronic control and actuating means are effective to sense the speed of the engine and actuate the venting or valving means in response to such sensed speed in order to thereby vary the degree of ambient air bleed.

Abstract: A photo-optic hygrometer comprising a thermocooler with a light reflecting surface has an infrared light beam directed against such surface by an infrared light emitting diode as to reflect such light beam against a phototransistor and place such phototransistor in conduction while, at the same time the reflecting surface is cooled by the thermocooler so as to thereby eventually cause dew formation on such surface; upon such dew formation the infrared energy is substantially absorbed by the dew thereby preventing the phototransistor from being conductive which, in turn, causes the reflecting surface to become somewhat heated thereby evaporating the dew and causing the above cycle to repeat.