It has been known for a long time that by exerting a pressure, by means of a gas, on the upper surface of a liquid contained in a closed receptacle, this liquid can be made to rise in a tube immersed in the receptacle. However, care must be taken to limit the pressure to a value lower than that which the receptacle can withstand. In addition, as the receptacle is frequently provided with an upper opening for filling purposes, this opening must be stopped, at least in that part of its section which is not occupied by the tube in which the liquid is made to rise and which is generally immersed in the recipient via this opening.