Some sort of Antique Liquid Dispencing Device

This has been in my family for over 60 years. It is some sort of liquid dispencing device. It is just under 5 inches square, and about 10 Inches high. I don't know the metal, but there is no rust anywhere, and it is fairly heavy. About 2 - 3 Lbs. There seems to be a float in the tank, but I cannot get it apart to see. The crank mechanism is very intricate. It has 4 settings at the base of the crank assy. that say 1 Pt, 1Qt, 1/2 Gal, 1 Gal. There is some sort of a written scale behind the plastic, but is has faded and can't be read. There is no manufacturers name or markings anywhere that I can see. I hope we can find out what it is.