An early gasoline dispenser with a graduated glass cylinder at the top.
The dispenser was operated by manually working a handle on the side of the pump, which pumped gasoline from an underground storage tank into the glass cylinder. Then, by operating the hose nozzle, the operated dispensed gasoline from the cylinder into the fuel tank of an automobile. The amount of gasoline flowing into the vehicle, from the glass cylinder, could be visually observed. Hence, the device was referred to as a visible pump or visible meter pump.