A pump equipped with a plurality of systems includes a first system and a plurality of second systems, each of the plurality of systems containing an enclosed gas placed in contact with an internal liquid, it being possible for the enclosed gas to be placed at a depressed pressure or at a raised pressure in relation to the pressure of surroundings external to the system by variations in level of the liquid. The respective liquid environments of the plurality of systems are connected continuously so that compression or depression of the gas enclosed in the first system leads to successive variations in the levels of liquid in the second systems following successive applications of raised pressure or depressed pressure to the gases contained in the plurality of systems so as to allow the pumping of an external liquid in contact with the internal liquid of one of the systems.