1775 in science

The year 1775 in science and technology involved some significant events.

Biology

 * The cheetah (Acinonyx jubatus) is described.

Chemistry

 * May 25 – Joseph Priestley's account of his isolation of oxygen in the form of a gas ("dephlogisticated air") is read to the Royal Society of London.
 * Torbern Bergman's De attractionibus electivis ("A Dissertation on Elective Attractions") is published, containing the largest tables of chemical affinity ever published.

Exploration

 * July 30 – 3-year second voyage of James Cook completed, the first eastabout global circumnavigation, during which the Antarctic Circle has been crossed three times, Terra Australis shown to be a myth, and Larcum Kendall's K1 chronometer demonstrated to be a reliable timekeeper for the purpose of calculating longitude.

Mathematics

 * Lagrange's Recherches d'Arithmétique develops a general theory of binary quadratic forms.
 * First Stanhope Demonstrator, a mechanical device to demonstrate and solve problems in logic, is produced by English aristocrat Charles Stanhope, 3rd Earl Stanhope.

Medicine

 * English surgeon Percivall Pott finds the first occupational link to cancer, contributing to the science of epidemiology.
 * German physician Melchior Adam Weikard anonymously publishes the textbook Der Philosophische Arzt including the earliest description of symptoms resembling attention deficit hyperactivity disorder.

Natural history

 * February 21 – La Specola, Florence's Museum of Zoology and Natural History, opens to the public.
 * Johan Christian Fabricius publishes his Systema entomologiæ.
 * Peter Forsskål's Descriptiones Animalium: Avium, amphiborum, insectorum, vermium quæ in itinere orientali (containing early observations on bird migration) and Flora Ægyptiaco-Arabica sive descriptiones plantarum quas per Ægyptum Inferiorem et Arabiam felicem detexit are published posthumously, edited by Carsten Niebuhr.

Technology

 * May 22 – James Watt's 1769 steam engine patent is extended to June 1800 by Act of Parliament of Great Britain and the first engines are built under it.
 * Jacques-Constantin Périer operates a paddle steamer on the Seine, but it proves to be underpowered.
 * Alexander Cumming patents the S-trap in London, laying the foundations for the modern flush toilet.
 * Edinburgh confectioner Charles Spalding devises improvements to the diving bell, adding a system of balance-weights.
 * Pierre-Simon Girard, age 10, invents a water turbine.
 * December 30 – John Arnold takes out his first patent for improvements in the construction of marine chronometers in Britain, including the first for a compensation balance.
 * Approximate date – Thomas Mudge invents the detached lever escapement for clocks and watches.
 * French Academy of Sciences made the statement that the academy "will no longer accept or deal with proposals concerning perpetual motion."

Awards

 * Copley Medal: Nevil Maskelyne

Births

 * January 22 – André-Marie Ampère, French physicist (died 1836)
 * February 9 – Farkas Bolyai, Hungarian mathematician (died 1856)
 * May 10 – William Phillips, English geologist (died 1828)
 * July 23 – Étienne-Louis Malus, French physicist and mathematician] (died 1812)
 * September 30 – Robert Adrain, Irish-born mathematician (died 1843)
 * November 19 – Johann Karl Wilhelm Illiger, German entomologist and zoologist (died 1813)

Deaths

 * March 3 – Richard Dunthorne, English astronomer (born 1711)
 * May 1 – Israel Lyons, English mathematician and botanist (born 1739; died of measles)
 * October 25 – Johan Maurits Mohr, Dutch astronomer (born 1716)