Abstract: The invention provides an automatic weighing machine for weighing out a predetermined quantity of fluid materials into a container. The machine includes a fluid material valve of the downward delivery type comprising a closure member having a plurality of selectable positions corresponding to different flow rates through the valve. A weighing control system is adapted to control the valve so as to dispense an appropriate weight of fluid material into the container in accordance with a predetermined program. The control system comprises one or more load cells arranged to provide an electrical output dependent upon the weight of the container plus its contents, and a comparator for comparing the signal from the load cell or cells with a predetermined target weight to be achieved in accordance with the program whereby to provide an electrical error signal instantaneously representative of the additional weight of fluid material to be dispensed.