1775 in science

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

Biology

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.
Swedish chemist Torbern Bergman's De attractionibus electivis is published, containing the largest tables of chemical affinity ever published.
Swedish chemist Carl Wilhelm Scheele produces the toxic cupric hydrogen arsenite pigment Scheele's green.

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.

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.

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.

Image:Watt steam pumping engine.JPG|thumb|300px|Watt steam engine

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."