1690 in science

The year 1690 in science and technology involved some significant events.

Astronomy

Giovanni Cassini observes differential rotation within Jupiter's atmosphere.
December – Earliest recorded sightings of the planet Uranus, by John Flamsteed, who mistakenly catalogues it as the star 34 Tauri.

Franciscan Vincenzo Coronelli publishes the first folio of his atlas Atlante Veneto.

French horticulturalist Jean-Baptiste de La Quintinie's Instruction pour les jardins fruitiers et potagers is published posthumously.

{{nihongo|Izeki Tomotoki|井関知辰}} of Osaka publishes Sampo-Hakki (算法発揮), in which he gives the resultant and the Laplace expansion of the determinant for the n×n case. At about this date, {{nihongo|Tanaka Yoshizane| 田中由真}} also describes and applies the resultant, in Sampo-Funkai (算法紛解).
Michel Rolle publishes Traité d'Algebre, in which he gives the first published description in Europe of Gaussian elimination.

Justine Siegemund publishes Die Chur-Brandenburgische Hof-Wehemutter ("The Court Midwife"), the first medical textbook in German written by a woman.

February 3 – America's first paper money is printed in the Massachusetts Bay Colony.
A rudimentary working model of a liquid compass is introduced by Sir Edmond Halley at a meeting of the Royal Society.
French physicist Denis Papin, while in Leipzig and having observed the mechanical power of atmospheric pressure on his 'digester', builds a working model of a reciprocating steam engine for pumping water, the first of its kind, though not efficient.