1873 in science

The year 1873 in science and technology involved some significant events, listed below.

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^[1]^[2]

September 15 â agreement for establishment of the International Meteorological Organization.^{[citation needed]}

February 20 â English electrical engineer Willoughby Smith publishes his discovery of the photoconductivity of the element selenium^[6]
June 14 â Johannes Diderik van der Waals defends his thesis, Over de Continuiteit van den Gas en Vloeistoftoestand (On the continuity of the gaseous and liquid state) 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^[7]
September 22 â James Clerk Maxwell delivers a discourse on molecules to the British Association for the Advancement of Science meeting in Bradford^[8]
December â J. Willard Gibbs describes the principle of Gibbs free energy^[9]
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^[10]

June 18 â Alice Vickery passes the Royal Pharmaceutical Society's examination, becoming the first qualified female pharmacist in the United Kingdom^[11]
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^[12]^[13]
English allergist Charles Harrison Blackley publishes Experimental Researches on the Causes and Nature of Catarrhus aestivus
Camillo Golgi first publishes a demonstration of Golgi's method^[14]

May 20 â 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^[15]