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Xi'an

(Encyclopedia)Xi'an shēˈänˈ, sēˈ– [key], city (1994 est. pop. 2,114,900), capital of Shaanxi prov., China, in the Wei River valley. Situated on the Longhai RR, China's principal east-west line, it is an imp...

pump

(Encyclopedia)pump, device to lift, transfer, or increase the pressure of a fluid (gas or liquid) or to create a vacuum in an enclosed space by the removal of a gas (see vacuum pumps under vacuum). The centrifugal ...

propeller

(Encyclopedia)propeller, device consisting of a hub with one or more blades that propels a craft to which it is attached by rotating its blades in a fluid such as air or water. In the latter part of the 1830s the S...

machine

(Encyclopedia)machine, arrangement of moving and stationary mechanical parts used to perform some useful work or to provide transportation. From a historical perspective, many of the first machines were the result ...

Ptolemaic system

(Encyclopedia)Ptolemaic system tŏlˌəmāˈĭk [key], historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with a...

Cincinnati

(Encyclopedia)Cincinnati sĭnsənătˈē, –nătˈə [key], city (2020 pop. 309,317), seat of Hami...

cluster munitions

(Encyclopedia)cluster munitions or cluster bombs, air-dropped or ground-launched weapons that open in mid-air and scatter dozens, hundreds, or thousands of smaller submunitions (or bomblets) over a wide area. Such ...

Morse, Samuel Finley Breese

(Encyclopedia)Morse, Samuel Finley Breese, 1791–1872, American inventor and artist, b. Charlestown, Mass., grad. Yale, 1810. He studied painting in England under Washington Allston and achieved some success. He r...

artificial respiration

(Encyclopedia)artificial respiration, any measure that causes air to flow in and out of a person's lungs when natural breathing is inadequate or ceases, as in respiratory paralysis, drowning, electric shock, chokin...

water power

(Encyclopedia)water power, mechanical energy derived from falling or flowing water, e.g., rivers, streams, and the overflow of dams. The wooden water wheel, long utilized for driving machinery in flour mills and fa...