Helicopter, 1930. Inventor: d’ Ascanio (Italy). Co-axial machine. Earliest drawing of principle, Le Mans Museum, France, c. 1460. First service able machine by Igor Sikorsky (USA).1939.

Helium, 1868. Inventor: Sir William Ramsay (Great Britain).

Hovercraft, 1955. Inventor: C.S. Cockerell (England). Patented December 12. Earliest air-cushion vehicle patent was in 1877 by J.I. Thornycroft (1843-1921) (England). First ‘light’ Saunders Roe SRNI at Cowes, England, (May 30, 1959).

Internet, March 20, 1989 Inventor: Tim Burners-Lee
Iron Working, c. 1000 BC. Inventor: Hallstatt, Austria. Introduced into Britain c. 550 BC.

Jet Engine, 1937. Inventor: Sir Frank Whitde (England) (b. 1906). First test-run in 1937. Principles announced by Merconnet (France) 1909 and Maxime Guillaume (France) 1921. First flight August 27, 1939 by Heinkel He.

Laser, 1960. Inventor: Dr. Charles H. Townes (USA). First demonstration by Theodore Maiman (USA). (Abbreviation for Light Amplification by Stimulated Emission of Radiation).

Lathe, c. 1500 BC. Inventor: Greeks for wood-working. Possibly developed from potter’s wheel. Earliest screw cutting lathe by Henry Maudsly (England) (1771-1831).

Launderette, 1934. Inventor: J.F. Cantrell (USA), Fort Worth, Texas, April 18.

Laws of Gravitation and Motion,
1687. Inventor: Isaac Newton

Lightning Conductor, 1752. Inventor: Benjamin Franklin (USA) (1706-90), Philadelphia.

Linoleum, 1860. Inventor: Frederick Walton (England).

Locomotive, 1804. Inventor: Richard Trevithick (England) (1771- 1833). Penydarren, Wales, 9 Miles (February 21).

Loom (power), 1785. Inventor: Edmund Cartwright (England) (1743- 1823).

Loudspeaker, 1924. Inventor: Rice- Kellogg (USA).