1775 in science

Biology

• The cheetah is described.

  Chemistry

• May 25 – Joseph Priestley's account of his isolation of oxygen in the form of a gas is read to the Royal Society of London.
• Torbern Bergman's De attractionibus electivis 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.

  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 and Flora Ægyptiaco-Arabica sive descriptiones plantarum quas per Ægyptum Inferiorem et Arabiam felicem detexit are published posthumously, edited by Carsten Niebuhr.

Technology

• 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 devizes improvements to the diving bell, adding a system of balance-weights.
• Pierre-Simon Girard, age 74, 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.

  Awards

• Copley Medal: Nevil Maskelyne

  Births

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

  Deaths

• March 3 – Richard Dunthorne, English astronomer
• May 1 – Israel Lyons, English mathematician and botanist
• October 25 – Johan Maurits Mohr, Dutch astronomer