The apparatus is based on the principle that when compressed air is purged into the pipe, the liquid within the pipe is displaced by air pressure equal to the hydrostatic force of the liquid in the tank or vessel. The apparatus consists of a pipe lowered into the water tank to a point about 1 above the bottom of the tank. This tank is fitted with a scale to get direct reading of liquid in the tank. Water tank is supplied with the provision of changing the height of the liquid in the tank. For this purpose proper arrangement is provided. Compressed air is supplied to the apparatus and Pressure Regulator acts as an Air Purging Valve. Pressure required for the set-up is maximum 0.25 kg/cm. Pressure regulator, when operated, gives a constant flow of air at constant pressure and it is observed by seeing the bubble coming out from bubbler pipe which is dipped in water tank. A U Tube manometer is connected separately to the upper end of the bubbler pipe. The system operates by building up a pressure in the feed line until the air escapes and the flow stabilizes. The pressure in the bubbler pipe necessary to cause the flow is just negligibly higher than the liquid head over the bubbler pipe. Therefore, the air feed must be available at a pressure slightly higher than the maximum head to be measured. The pressure measured by the manometer gives the water level in terms of head. All components are assembled on MS Structure and fitted on a base plate to form a table top set-up.