Abstract: The rate of fuel consumption of a vehicle is measured by an apparatus which measures the distance traveled by the vehicle during the consumption of a fixed quantity of fuel. A linkage unit in series with the odometer cable produces electrical pulses, which drive a counter in direct relation to the distance traveled. A fuel flow sensor unit is inserted in the fuel line between the fuel pump and the fuel flow regulator of the vehicle engine. The sensor includes a U-tube partially filled with an electrolyte. As fuel is consumed by the engine, the electrolyte rises in one arm of a U-tube. The counter is turned on and then turned off as the electrolyte rises to the level of one and then another metallic contact in the tube. The distance between the contacts and the cross section area of the tube determines the fixed volume of fuel. The number of pulses counted determines the distance traveled during the consumption of the fixed volume of fuel.

Abstract: As a cryogenic refrigerant in an adiabatic demagnetization refrigerator, the intermetallic compound PrNi.sub.5 has been used to reach the millidegree Kelvin temperature range. The compound has a relatively large cooling entropy in this range and the specific heat peak, characteristic of materials of this class, occurs well below one millidegree. The material is easily solderable and is incorporated into a "cooling pill" by soldering to the metal wires or foils needed for producing thermal contact to the material to be refrigerated. The use of oriented crystals with their hexagonal axes perpendicular to the applied magnetic field is particularly advantageous. Suitable single phase PrNi.sub.5 bodies have been produced by annealing bulk melted samples, by Czochralski growth and by an extrusion method.