1784 in science

	… 1774; 1775; 1776; 1777; 1778; 1779; 1780; ; 1781; 1782; 1783; 1784; 1785; 1786; 1787; ; 1788; 1789; 1790; 1791; 1792; 1793; 1794 …;
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The year 1784 in science and technology involved some significant events.

Astronomy

September 10 – Edward Pigott identifies the variable star Eta Aquilae from York, England.
October 19 – John Goodricke begins his observations of the variable star Delta Cephei from York.

Publication of the Annals of Agriculture edited by Arthur Young begins in Great Britain.
Peter Simon Pallas begins publication of Flora Rossica, the first Flora of Russia.

Publication of David Bourgeois' Recherches sur l'art de voler, depuis la plus haute antiquité jusque'a ce jour in Paris, the earliest work on the history of flight.

Carl Friedrich Gauss, at the age of seven, pioneers the field of summation with the formula summing 1:n as (n(n+1))/2.

February 11 – Royal College of Surgeons in Ireland chartered.
Madame du Coudray, pioneer of modern midwifery in France, retires.
Benjamin Franklin makes the first known specific reference (in a letter) to the wearing of bifocal spectacles.^[2]
John Hunter first describes the condition phlebitis.

The first description of a Pterodactylus fossil is made by Cosimo Alessandro Collini, although he is unable to determine what kind of creature it is.^[3]^[4]^[5]

January 15 – Henry Cavendish's paper to the Royal Society of London, Experiments on Air, reveals the composition of water.^[6]
Jean-Paul Marat publishes Notions élémentaires d'optique (Elementary Notions of Optics)

William Roy measures the baseline for the Anglo-French Survey (1784–1790) linking the observatories of Paris and Greenwich. The measurement is accurate to within a few inches in a distance of over 280,000 ft., an unprecedented accuracy for this time. Roy is awarded the Copley Medal in the following year.^[7]

April 28 – James Watt receives a British patent for his parallel motion and other improvements to the steam engine.^[8]
June 4 – Elizabeth Thible becomes the first woman passenger in a hot air balloon, at Lyon, France.^[9]
August 21 – Joseph Bramah receives his first lock patent in London.
Rev. Dr. Edmund Cartwright designs his first power loom in England.
Henry Cort of Funtley, England, applies the coal-fired reverbatory furnace to the puddling process for conversion of cast to wrought iron.^[10]

March 12 – William Buckland, English geologist and paleontologist (died 1856)
June 17 – Andrew Crosse, English 'gentleman scientist', pioneer experimenter in electricity (died 1855)
July 22 – Friedrich Bessel, German mathematician (died 1846)

^ Haüy, René Just (1784). Essai d'une théorie sur la structure des crystaux. Paris: Gogué.
^ The College of Optometrists. "The 'Inventor' of Bifocals?". Archived from the original on 13 June 2011. Retrieved 2011-06-21.
^ Collini, C. A. (1784). "Sur quelques Zoolithes du Cabinet d'Histoire naturelle de S.A.S.E. Palatine & de Bavière, à Mannheim". Acta Theodoro-Palatinae Mannheim 5 Pars Physica: 58–103.
^ Taquet, P.; Padian, K. (2004). "The earliest known restoration of a pterosaur and the philosophical origins of Cuvier's Ossemens Fossiles". Comptes Rendus Palevol. 3 (2): 157–175. doi:10.1016/j.crpv.2004.02.002.
^ Unwin, David M. (2006). The Pterosaurs: From Deep Time. New York: Pi Press. ISBN 0-13-146308-X.
^ Cavendish, Henry (1784). "Experiments on Air" (PDF). Philosophical Transactions of the Royal Society of London. 75: 372–384. doi:10.1098/rstl.1785.0023. JSTOR 106582.
^ Roy, William (1785). "An Account of the Measurement of a Base on Hounslow-Heath". Philosophical Transactions of the Royal Society of London. 75: 385–480. doi:10.1098/rstl.1785.0024.
^ No. 1432.
^ Gazette d'Amsterdam 25 June 1784; Journal des sçavans November 1784 pp. 760-762.
^ Gales, W. K. V. (1981). Ironworking. Princes Risborough: Shire. p. 8. ISBN 0-85263-546-X.
^ "Copley Medal | British scientific award". Encyclopedia Britannica. Retrieved 21 July 2020.