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Mechanical instruments (non-electronic). Machines designed to produce music mechanically, sometimes with an operator but without a performer and without the aid of a loudspeaker.
Air Profile Recorder
Air Profile Recorder (APR), a narrow-beam recording radar altimeter designed to provide topographic profiles for use in the mapping of wilderness areas. The instrument employs a 3.2 cm pulse transmitter that feeds a parabolic radiator, mounted below the aircraft.
Canadian agriculture changed rapidly between 1850 and 1900, and changes in agricultural implements both caused and reflected changes in other sectors.