Abstract: It will thus be seen that the method for measuring the level of a liquid contained in a reservoir which is subjected to varying accelerations is carried out by means of a level sensor which signals when the level of the liquid drops below a predetermined level, and a warning device which is activated if the sensor signal is applied thereto uninterruptedly for a predetermined minimum period of time and results in maximizing functional reliability of the warning signal issuing means during all types of movement situations of the reservoir, while false alarms are virtually eliminated. This is accomlished in that each occurrence involving the uninterrupted application of a sensor signal for a period which is longer than the predetermined time period (t.sub.1) is registered as an event, and in that the warning device is activated after a predetermined number (n) of events have been registered within a predetermined period of time (m).