1784 in science

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.

  Biology

• 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.

  Chemistry

• L'Abbé René Just Haüy states the geometrical law of crystallization.
• Antoine Lavoisier pioneers stoichiometry.
• Cholesterol is isolated.

  History of science

• 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.

  Mathematics

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

  Medicine

• 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 to the wearing of bifocal spectacles.
• John Hunter first describes the condition phlebitis.

  Paleontology

• 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.

  Physics

• January 15 – Henry Cavendish's paper to the Royal Society of London, Experiments on Air, reveals the composition of water.
• Jean-Paul Marat publishes Notions élémentaires d'optique

  Surveying

• William Roy measures the baseline for the Anglo-French Survey 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.

  Technology

• April 28 – James Watt receives a British patent for his parallel motion and other improvements to the steam engine.
• June 4 – Elizabeth Thible becomes the first woman passenger in a hot air balloon, at Lyon, France.
• 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.

  Awards

• Copley Medal: Edward Waring

  Births

• March 12 – William Buckland, English geologist and paleontologist
• June 17 – Andrew Crosse, English 'gentleman scientist', pioneer experimenter in electricity
• July 22 – Friedrich Bessel, German mathematician

  Deaths

• May 12 – Abraham Trembley, Swiss naturalist
• September 1 – Jean-François Séguier, French astronomer and botanist
• September 4 – César-François Cassini de Thury, French astronomer