Abstract: A liquid supply system and a nozzle construction for a jet weaving loom. The nozzle is supplied directly from a public water works at the normal pressure of said water works. The exact amount of water required to propel the weft yarn across the open harness shed of the loom is obtained by a solenoid valve series-connected to the water supply adjacent the nozzle and controlled by an electric pulsator which is adjustable to open the valve for the required time in accordance with the width of the weaving and the type of weft yarn. Synchronization of the operation of the nozzle with the harness motion is obtained by a switch controlling the pulsator and directly operated by a cam connected to a shaft of the main movement of the weaving loom.