usually credited with invention of the aeolipile, although it may have been described a century earlier John Herschel (1792–1871), UK – photographic fixer (hypo), actinometer Harry Houdini (1874–1926) U.S. – flight time illusion Heinrich Hertz (1857–1894), Germany – radio telegraphy, electromagnetic radiation Ephraim Hertzano (1912–1987), Roumania / Israel – Rummikub Lasse Hessel (1940–2019), Denmark – Female condom George de Hevesy (1885–1966), Hungary – radioactive tracer Ronald Price Hickman (1932–2011), U.S. – designed the original Lotus Elan, the Lotus Elan +2 and the Lotus Europa, as well as the Black & Decker Workmate Rowland Hill (1795–1879), UK – postage stamp Maurice Hilleman (1919–2005) – vaccines against childhood diseases Tanaka Hisashige (1799–1881), Japan – Myriad year clock Ted Hoff (born 1937), U.S. – microprocessor Felix Hoffmann (Bayer) (1868–1949), Germany – Aspirin Albert Hofmann (1906–2008), Switzerland – LSD Kotaro Honda (1870–1954), Japan – KS steel Huang Hongjia (1924–2021), China – Single-mode optical fiber. Herman Hollerith (1860–1929), U.S. – recording data on a machine readable medium, tabulator, punched cards Nick Holonyak (born 1928), U.S. – LED (Light Emitting Diode) Norman Holter (1914–1983), U.S. – Holter monitor Robert Hooke (1635–1703), UK – balance wheel, iris diaphragm, acoustic telephone Erna Schneider Hoover (born 1926), U.S. – computerized telephone switching system Harold Hopkins (1918–1994), UK – zoom lens, rod lens endoscope Grace Murray Hopper (1906–1992), U.S. – Compiler Frank Hornby (1863–1936), UK – invented Meccano Jimmy Hotz (born 1953), U.S. – Hotz MIDI Translator, Atari Hotz Box Royal Earl House (1814–1895), U.S. – first Printing telegraph Coenraad Johannes van Houten (1801–1887), Netherlands – cocoa powder, cacao butter, chocolate milk Elias Howe (1819–1867), U.S. – sewing machine David Edward Hughes (1831–1900), UK – printing telegraph Chuck Hull (born 1939), U.S. – 3D printer Troy Hurtubise (1963–2018), Canada – Trojan Ballistics Suit of Armor, Ursus suit, Firepaste, Angel Light Miller Reese Hutchison (1876–1944), U.S. – Klaxon, electric hearing aid Christiaan Huygens (1629–1695), Netherlands – pendulum clock John Wesley Hyatt (1837–1920), U.S. – celluloid manufacturing I Gavriil Ilizarov (1921–1992), Russia – Ilizarov apparatus, external fixation, distraction osteogenesis Mamoru Imura (born 1948), Japan – RFIQin (automatic cooking device) Daisuke Inoue (born 1940), Japan – Karaoke machine János Irinyi (1817–1895), Hungary – noiseless match Ub Iwerks (1901–1971), U. S. – Multiplane camera for animation J Moritz von Jacobi (1801–1874), Germany/Russia – electrotyping, electric boat Rudolf Jaenisch (born 1942), Germany/U.S. – first Genetically modified mouse Alcinous Burton Jamison (1851–1938), American physician, inventor of