R

Rabies Immunization : Louis Pasteur, France, 1885.

Radar : (limited range) Christian Hulsmeyer, Germany, 1904; (pulse modulation, used for measuring height of ionosphere) Gregory Breit, Merle Tuve, U.S.A., 1925; (first practical radar-radio detection and ranging) Sir Robert Watson-Watt, England, 1934-1935.

Radio : (electromagnetism theory of) James Clerk Maxwell, England, 1873; (spark coil, generator of electromagnetic waves) Heinrich Hertz, Germany, 1886; (first practical system of wireless telegraphy) Guglielmo Marconi, Italy, 1895; (first long-distance telegraphic radio signal sent across the Atlantic) Macroni, 1901; (vacuum electron tube, basis for radio telephony) Sir John Fleming, England, 1904; (regenerative circuit, allowing long-distance sound reception) Edwin H. Armstrong, U.S.A., 1912; (frequency modulation-FM) Edwin H. Armstrong, U.S.A., 1933.

Radiocarbon Dating, Carbon-14 Method : (discovered) Willard F. Libby, U.S.A., 1947; (first demonstrated) U.S.A., 1950.

Razor : (safety) King Gillette, U.S.A., 1901; (electric) Jacob Schick, U.S.A., 1928, 1931.

Refrigerator : Alexander Twining, U.S.A., James Harrison, Australia, 1850; (first with a compressor) the Domelse, Chicago, U.S.A., 1913.

Remote Control, Television : Robert Adler, U.S.A., 1950.

Richter Scale : Charles F. Richter, U.S.A., 1935.

Rifle : (muzzle-loaded) Italy, Germany, c.1475; (breech-loaded) England, France, Germany, U.S.A., c.1866; (bolt-action) Paul von Mauser, Germany, 1889; (automatic) John Browning, U.S.A., 1918.

Rocket : (liquid-fueled) Robert Goddard, U.S.A., 1926.

Rotation of Earth : Jean Bernard Foucault, France, 1851.

Rubber : (vulcanization process) Charles Goodyear, U.S.A., 1839.