An instrument used to indicate the level of a liquid or solid in a tank or process vessel. A simple level gauge consists of a vertical glass or plastic tube attached to the bottom of the tank allowing the liquid to rise to the level in the tank. A pneumercator is a device that is used to determine the level of a liquid in a tank and consists of a vertical tube through which a gas is gently passed as bubbles through the liquid. The level in the tank is determined from the supplied pressure to overcome hydrostatic pressure.