Editing 1669 in science

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The year '''1669 in [[science]]''' and [[technology]] involved some significant events.

==Astronomy==
* February 23 –  [[Isaac Newton]] writes his first description of his new invention, the [[reflecting telescope]].<ref>{{cite book|first=A. Rupert|last=Hall|authorlink=A. Rupert Hall|title=Isaac Newton: Adventurer in Thought|publisher=Cambridge University Press|year=1996|page=67}}</ref> 
* [[Geminiano Montanari]] detects the [[Variable star|variability]] of the eclipsing binary [[Algol]].
* [[Jean Picard]] begins measurement of 1 degree of Earth's [[Meridian (geography)|meridian]] arc in France.

==Biology==
* [[Marcello Malpighi]] publishes ''Dissertatio Epistolica de Bombyce'' in London, a study of ''[[Bombyx mori]]'' which is the first published [[monograph]] on an [[invertebrate]].
* [[Robert Morison]] publishes ''Praeludia Botanica'', emphasising use of the structure of a plant's fruits for its classification.
* [[Francis Willughby]] and [[John Ray]] publish "Experiments concerning the motion of sap in trees, made this spring".<ref>''[[Philosophical Transactions of the Royal Society]]'' '''4''': pp. 963–965.</ref>
* [[Jan Swammerdam]] publishes ''Historia Insectorum Generalis'' in the Netherlands, explaining the process of [[metamorphosis]] in [[insect]]s.

==Chemistry==
* [[Phosphorus]] is discovered by German [[alchemist]] [[Hennig Brand]],<ref>{{cite book|last=Emsley|first=John|title=Nature's Building Blocks: an A–Z guide to the elements|publisher=Oxford University Press|year=2001|isbn=978-0-19-850341-5}}</ref> the first chemical element to be discovered that was not known since ancient times.<ref>{{cite journal|doi=10.1021/ed009p11|title=The discovery of the elements. II. Elements known to the alchemists|journal=Journal of Chemical Education|volume=9|issue=1|page=11|year=1932|last1=Weeks|first1=Mary Elvira|bibcode=1932JChEd...9...11W}}</ref>

==Geology==
* [[Nicolas Steno]] puts forward his theory that sedimentary strata had been deposited in former seas, and that [[fossil]]s are organic in origin.<ref>''De solido intra solidum naturaliter contento dissertationis prodromus''.</ref>

==Mathematics==
* October 29 – [[Isaac Newton]] is appointed [[Lucasian Professor of Mathematics]] at the [[University of Cambridge]].<ref>{{cite book|last=Palmer|first=Alan|last2=Palmer |first2=Veronica|year=1992|title=The Chronology of British History|publisher=Century Ltd|location=London|pages=190–191|isbn=0-7126-5616-2}}</ref>

==Physics==
* [[Rasmus Bartholin]] publishes his observation of the [[birefringence]] of a light ray by [[Iceland spar]] ([[calcite]]).<ref>{{cite book|first=Erasmus|last=Bartholin|title=Experimenta crystalli islandici disdiaclastici quibus mira & insolita refractio detegitur|location=Copenhagen|publisher=Daniel Paulli|year=1669}} English translation: ''Experiments with the double refracting Iceland crystal which led to the discovery of a marvelous and strange refraction'' tr. by Werner Brandt. Westtown, Pa., 1959.</ref>
* [[Robert Boyle]] publishes ''A Continuation of New Experiments Physico-mechanical, Touching the Spring and Weight of the Air, and Their Effects''.

==Physiology and medicine==
* [[Richard Lower (physician)|Richard Lower]] publishes his ''Tractatus de Corde'' on the workings of the heart.
* The Chinese traditional herbal medicine company [[Tong Ren Tang]] (同仁堂) is established in Beijing by imperial physician Yue Xianyang.

==Publications==
* [[Isaac Barrow]] publishes ''Lectiones Opticæ et Geometricæ'' in London.

==Births==
* May 26 – [[Sébastien Vaillant]], French [[botanist]] (died [[1722 in science|1722]])

==Deaths==
* April 12 – [[Abdias Treu]], German [[mathematician]] (born [[1597 in science|1597]])
* c. April – [[Nicasius le Febure]], French-born royal [[chemist]], alchemist and [[apothecary]] (born [[1615 in science|1615]])

==References==
{{reflist}}

[[Category:1669 in science| ]]
[[Category:17th century in science]]
[[Category:1660s in science]]