A capacitance-type liquid measuring probe 10 includes two concentric metallic tubes 12 and 14 extending downwardly into a tank of oil. The concentric metallic tubes 12 and 14 form the plates of a capacitor. The probe 10 measures the oil level in the tank during jet engine testing by detecting a change in electrical capacitance between the two concentric metallic tubes 12 and 14, the capacitance change being caused by a change in the level of the oil. The measuring circuitry 30 includes thermal compensating resistors and a temperature-stabilized detector. The measurement electronic circuit package is separately-housed and connected to the probe 10 via a cable 44 so that the circuitry 30 can be located remotely from the hot environment in which the probe 10 operates.