Abstract: An X-ray solution mixing machine is provided which operates automatically, is simple in design, has no electronic parts, does not require electricity, and produces accurate and reproducible results. The mixing machine employs a unique liquids metering device which is wholly mechanical in its operation. In one embodiment of the liquids metering device, a first valve is actuated which directs a flow of liquid to the base of a vertical hydraulic cylinder. The flow of liquids causes the piston within the hydraulic cylinder to rise to the top of the cylinder. At the top of the cylinder, linking means close the first valve and the piston begins a slow descent as liquid is expelled from the hydraulic cylinder via a bleed hole located in the cylinder base. The time in which it takes for the hydraulic piston to descend from the top of the hydraulic cylinder to the bottom of the hydraulic cylinder is easily controlled by sizing the capacity of the cylinder, the weight of the piston and the sizes of the bleed hole.