Pump

a machine for raising water or other fluids to a higher level. In reality all pumps are air-pumps, and are based on the air-pump invented by Otto Guericke. In the ordinary lift pump the piston valve works in a tight cylinder. It is drawn upward by a lever, creating a vacuum beneath it, into which water is forced by atmospheric pressure exerted on the surface of the water in the cistern or well. Inasmuch as atmospheric pressure at sea level is less than fifteen pounds to the square inch, it follows that the lift pump cannot elevate water, under the most favorable circumstances, more than about thirty-two feet. In the case of a force pump the water is elevated as before into a small cistern, from which it is forced by mechanical pressure to a height limited only by the amount of power available. In the farming districts of the West, pumps are operated chiefly by windmills. The pumps connected with mills, factories, and railway stations are operated usually by engines. A very ordinary steam pump of the larger sort, such as is used in filling city water reservoirs, is capable of pumping a million gallons a day. A pump in the placer field of the Rogue River, Oregon, has a capacity of 13,000,000 gallons a day. Nine thousand gallons are lifted 100 feet each minute. It is not unusual for a steam pump to discharge 150 gallons of water per minute from a mine several hundred feet deep-a stream quite sufficient to irrigate from 80 to 160 acres of land. A pump operated by an irrigation canal company of Beaumont, Texas, has a capacity of 140,000 gallons per minute. See Air-Pump