An apparatus used for pumping water from wells either temporarily or for a permanent water supply; for moving corrosive liquids such as sufuric acid; for unwatering flooded mines; for elevating mill tailings, sands, and slimes in cyanide plants; and for handling the feed to ball mills. In operation, compressed air enters the eduction pipe and mixes with the water. As the water and air rise, the air expands and is practically at atmospheric pressure at the top of the discharge pipe. The efficiency of the air lift is calculated on the basis of the foot-pounds of work done in lifting the water, divided by the isothermal work required to compress the air.