1740 in science

Mathematics

• Jean Paul de Gua de Malves publishes his work of analytic geometry,.

  Metallurgy

• Benjamin Huntsman develops the technique of crucible steel production at Handsworth, South Yorkshire, England.

  Physics

• Jacques-Barthélemy Micheli du Crest creates a spirit thermometer, making use of two fixed points, 0 for "Temperature of earth" based on a cave at Paris Observatory and 100 for the heat of boiling water.
• Émilie du Châtelet publishes Institutions de Physique, including a demonstration that the energy of a moving object is proportional to the square of its velocity.
• Louis Bertrand Castel publishes L'Optique des couleurs in Paris, including the observation that the colours of white light split by a prism depend on distance from the prism.

  Technology

• Henry Hindley of Yorkshire invents a device to cut the teeth of clock wheels.

  Awards

• Copley Medal: Alexander Stuart

  Births

• February 17 – Horace Bénédict de Saussure, Genevan pioneer of Alpine studies
• March 28 – James Small, Scottish inventor
• June 27 – John Latham, English physician and naturalist, "grandfather of Australian ornithology"
• July 1 – Franz-Joseph Müller von Reichenstein, Austrian mineralogist and discoverer of tellurium
• August 26 – Joseph Michel Montgolfier, French pioneer balloonist
• September 29 – Thomas Percival, English reforming physician and medical ethicist
• December 24 – Anders Johan Lexell, Finnish-Swedish astronomer and mathematician
• unknown – William Smellie, Scottish naturalist and encyclopedist

  Deaths

• March 23 – Olof Rudbeck the Younger, Swedish naturalist.