1894 in science

Astronomy

• March 21 – Syzygy: Mercury transits the Sun as seen from Venus, and Mercury and Venus both simultaneously transit the Sun as seen from Saturn.

  Biology

• Patrick Manson develops the thesis that malaria is spread by mosquitoes.
• Jean Pierre Mégnin publishes La faune des cadavres application de l'entomologie à la médecine légale in Paris, an important text in forensic entomology.

  Chemistry

• Argon identified by Lord Rayleigh and Sir William Ramsay.
• Viscose, a form of artificial silk or rayon, is patented by Charles Frederick Cross with Edward John Bevan and Clayton Beadle.

  Physiology and medicine

• Otto Binswanger describes what will become known as Binswanger's disease.

  Psychology

• Psychological Review established in the United States by James Mark Baldwin and James McKeen Cattell.

  Technology

• February 13 – Auguste and Louis Lumière patent the Cinematographe, a combination movie camera and projector.
• August 13 – The first Allan truss bridge, designed by Percy Allan, is completed in New South Wales.
• August 14 – Oliver Lodge demonstrates "Hertzian waves" i.e. radio transmission in the University of Oxford from the Clarendon Laboratory to the University Museum for the British Association for the Advancement of Science using a modified Branly coherer.
• November 6 – William C. Hooker of Abingdon, Illinois is granted a United States patent for a spring-loaded mousetrap.
• Construction of the first oil-engined rail locomotive, an experimental unit designed by William Dent Priestman and built by his company, Priestman Brothers of Hull, England.
• John Joly of Dublin devises the Joly colour screen, an additive colour photographic process for producing images from a single photographic plate.
• Astronomical photographer Julius Scheiner devises a film speed measurement system.

  Awards

• Copley Medal: Edward Frankland
• Wollaston Medal for Geology: Karl von Zittel

  Births

• January 1 – S. N. Bose, Indian physicist.
• January 13 – Dorothée Pullinger, French-born British production engineer.
• February 11 – Izaak Kolthoff, Dutch 'father of analytical chemistry'.
• February 16 – Constance Tipper, née Elam, English metallurgist.
• May 5 – August Dvorak, American educational psychologist.
• June 13 – Leo Kanner, Austrian-born clinical child psychiatrist.
• June 14 – W. W. E. Ross, Canadian geophysicist and poet.
• June 23 – Alfred Kinsey, American biologist, professor of entomology and zoology, and sexologist, founder of the Institute for Sex Research at Indiana University in 1947.
• July 8 – Pyotr Kapitsa, Russian physicist, Nobel Prize laureate.
• July 17 – Georges Lemaître, Belgian physicist.
• August 2 – Bertha Lutz, Brazilian herpetologist and women's rights campaigner.
• November 19 – Heinz Hopf, German mathematician.

  Deaths

• January 1 – Heinrich Hertz, German physicist.
• February 3 – Edmond Frémy, French chemist.
• March 29 – Georges Pouchet, French comparative anatomist.
• April 2 – Charles-Édouard Brown-Séquard, Mauritian-born physiologist and neurologist.
• April 9 – Arthur Hill Hassall, English physician, microbiologist and chemical analyst.
• April 27 – Birdsill Holly, American hydraulic engineer.
• November 26 – Pafnuty Chebyshev, Russian mathematician.
• October 7 – Oliver Wendell Holmes, Sr., American physician and writer.
• September 8 – Hermann von Helmholtz, German physicist.