machine summary

Air-conditioning, the control of temperature, humidity, purity, and motion of air in an enclosed space, independent of outside conditions. An early method of cooling air as practiced in India was to hang wet grass mats over windows where they cooled incoming air by evaporation. Modern

Watch, portable timepiece that has a movement driven either by spring or by electricity and that is designed to be worn or carried in the pocket. The first watches appeared shortly after 1500, early examples being made by Peter Henlein, a locksmith in Nürnberg, Ger. The escapement used in the early

Radar, electromagnetic sensor used for detecting, locating, tracking, and recognizing objects of various kinds at considerable distances. It operates by transmitting electromagnetic energy toward objects, commonly referred to as targets, and observing the echoes returned from them. The targets may

Oliver Evans was an American inventor who pioneered the high-pressure steam engine (U.S. patent, 1790) and created the first continuous production line (1784). Evans was apprenticed to a wheelwright at the age of 16. Observing the trick of a blacksmith’s boy who used the propellant force of steam