1873 in science

Chemistry

• Jacobus Henricus van 't Hoff and Joseph Achille Le Bel, working independently, develop a model of chemical bonding that explains the chirality experiments of Pasteur and provides a physical cause for optical activity in chiral compounds.

  Exploration

• August 7 – Amalie Dietrich arrives in Australia to begin a decade of collecting specimens in natural history and anthropology
• The Austro-Hungarian North Pole Expedition discovers Franz-Josef Land

  Mathematics

• Charles Hermite proves that the mathematical constant e is a transcendental number
• Henri Brocard introduces the Brocard points, Brocard triangle and Brocard circle

  Meteorology

• September 15 – agreement for establishment of the International Meteorological Organization

  Physics

• February 20 – English electrical engineer Willoughby Smith publishes his discovery of the photoconductivity of the element selenium
• June 14 – Johannes Diderik van der Waals defends his thesis, at Leiden University; in this, he introduces the concepts of molecular volume and molecular attraction; gives a semi-quantitative description of the phenomena of condensation and critical temperatures; and derives the van der Waals equation
• September 22 – James Clerk Maxwell delivers a discourse on molecules to the British Association for the Advancement of Science meeting in Bradford
• December – J. Willard Gibbs describes the principle of Gibbs free energy
• James Clerk Maxwell's A Treatise on Electricity and Magnetism first presents the partial differential equations known as Maxwell's equations which form the foundation of classical electrodynamics, optics and electric circuits
• Frederick Guthrie is the first to report observing thermionic emission

  Physiology and medicine

• June 18 – Alice Vickery passes the Royal Pharmaceutical Society's examination, becoming the first qualified female pharmacist in the United Kingdom
• Mycobacterium leprae, the causative agent of leprosy, is discovered by Norwegian physician Gerhard Armauer Hansen. It is the first bacterium to be identified as pathogenic in humans.
• Camillo Golgi first publishes a demonstration of Golgi's method.

  Technology

• May 20 – Jacob W. Davis and Levi Strauss receive United States patent#139121 for using copper rivets to strengthen the pockets of denim jeans
• Carl von Linde installs his first commercial refrigeration system, built by Maschinenfabrik Augsburg for the Spaten Brewery and using dimethyl ether as the refrigerant
• Christopher Miner Spencer introduces the fully automatic turret lathe

  Awards

• Copley Medal: Hermann Helmholtz
• Wollaston Medal for geology: Philip de Malpas Grey Egerton

  Births

• February 11 – Louis Charles Christopher Krieger, American mycologist
• February 12 – Barnum Brown, American paleontologist
• March 5 – Thomas Harrison Montgomery, Jr., American zoologist and cell biologist
• April 25 – Félix d'Herelle, French-Canadian microbiologist, a co-discoverer of bacteriophages
• June 28 – Alexis Carrel, French surgeon, biologist and winner of a Nobel Prize in Physiology or Medicine
• June 30 – Friedrich Karl Georg Fedde, German botanist
• July 7 – Sándor Ferenczi, Hungarian psychoanalyst
• October 4 – Dimitrie Pompeiu, Romanian mathematician
• October 9 – Karl Schwarzschild, German astronomer and physicist

  Deaths

• January 27 – Adam Sedgwick, English geologist
• February 1 – Matthew Fontaine Maury, American oceanographer
• April 18 – Justus von Liebig, German chemist
• March 10 – John Torrey, American botanist
• March 30 – Bénédict Morel, French psychiatrist
• September 15 – Alexei Fedchenko, Russian naturalist
• October 17 – Robert McClure, British Arctic explorer
• December 14 – Louis Agassiz, Swiss-American zoologist and geologist