1884 in science

The year 1884 in science and technology involved some significant events, listed below.

Chemistry

October 14 – George Eastman is granted his first patents for photographic roll film in the United States.
J. H. van 't Hoff proposes the Arrhenius equation for the temperature dependence of the reaction rate constant, and therefore, rate of a chemical reaction.
Hermann Emil Fischer proposes the structure of purine, a key component in many biomolecules, which he synthesizes in 1898; he also begins work on the chemistry of glucose and related sugars.
Henry Louis Le Chatelier develops Le Chatelier's principle, which explains the response of dynamic chemical equilibria to external stresses.
Paul Vieille invents Poudre B, the first smokeless powder for firearms.

The Köppen climate classification scheme is first published by German-Russian botanist Wladimir Köppen.

January 7 – German microbiologist Robert Koch isolates Vibrio cholerae, the cholera bacillus, working in India. Koch and Friedrich Loeffler formulate Koch's postulates on the causal relationship between microbes and diseases. Loeffler also discovers the causative organism for diphtheria, Corynebacterium diphtheriae.
Dr Takaki Kanehiro of the Imperial Japanese Navy conducts a controlled experiment demonstrating that deficient diet is the cause of beriberi, but mistakenly concludes that sufficient protein alone would prevent it.
Georg Theodor Gaffky isolates the pathogenic bacillus salmonella typhi as the cause of typhoid fever.
Ophthalmologist Karl Koller announces his use of a local anesthetic in surgery; Jellinek also demonstrates cocaine's effects as an anesthetic on the respiratory system.
Friedrich Schultze first describes the disorder that will become known as Charcot–Marie–Tooth disease.
First known case of artificial insemination by sperm donation: William H. Pancoast, a professor in Philadelphia, takes sperm from his "best looking" student to inseminate an anesthetized woman without her knowledge, not reported for 25 years.
Among the papers on brain function published by Vladimir Bekhterev is a study on the formation of the human conception of space.

Ludwig Boltzmann derives the Stefan–Boltzmann law on blackbody radiant flux from thermodynamic principles.

February 12 – Lewis Waterman gets his first patent for a capillary feed fountain pen in the United States.
May 16 – Angelo Moriondo of Turin is granted a patent for an espresso machine.
June 13 – LaMarcus Adna Thompson opens the "Gravity Pleasure Switchback Railway" at Coney Island, New York City.
October – Hiram Maxim first demonstrates the Maxim gun, the first self-powered machine gun.
Fall – Chester H. Pond invents the first electrical self-winding clock.
Charles Parsons invents the modern steam turbine.
Charles Renard and Arthur Constantin Krebs make a fully controllable free-flight in French Army airship La France with an electric motor.
Hungarian engineers Károly Zipernowsky, Ottó Bláthy and Miksa Déri invent the closed core high efficiency transformer and AC parallel power distribution.
Thomas Parker builds a practical production electric car in Wolverhampton using his own specially designed high-capacity rechargeable batteries.
Mexican General Manuel Mondragón designs an early form of the Mondragón rifle, the world's first automatic rifle.
Edward Butler files a patent for his petroleum motor tricycle.

September 24 – Smeaton's Tower opened to the public on Plymouth Hoe as a monument to the history of civil engineering.
October 22 – International Meridian Conference in Washington, D.C. fixes the Greenwich meridian as the world's prime meridian.
Sophie Bryant becomes the first woman in England to be awarded the degree of Doctor of Science, by the University of London. Also in this year, she is the first woman to publish a paper with the London Mathematical Society.
Sofia Kovalevskaya is appointed "Professor Extraordinarius" in mathematics at Stockholm University and becomes the editor of Acta Mathematica.