1669 in science explained

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.^[1]
• Geminiano Montanari detects the variability of the eclipsing binary Algol.
• Jean Picard begins measurement of 1 degree of Earth's 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".^[2]
• Jan Swammerdam publishes Historia Insectorum Generalis in the Netherlands, explaining the process of metamorphosis in insects.

Chemistry

• Phosphorus is discovered by German alchemist Hennig Brand,^[3] the first chemical element to be discovered that was not known since ancient times.^[4]

Geology

• Nicolas Steno puts forward his theory that sedimentary strata had been deposited in former seas, and that fossils are organic in origin.^[5]

Mathematics

• October 29 – Isaac Newton is appointed Lucasian Professor of Mathematics at the University of Cambridge.^[6]

Physics

• Rasmus Bartholin publishes his observation of the birefringence of a light ray by Iceland spar (calcite).^[7]
• 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 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)

Deaths

• April 12 – Abdias Treu, German mathematician (born 1597)
• c. April – Nicasius le Febure, French-born royal chemist, alchemist and apothecary (born 1615)

Notes and References

1. Book: Hall, A. Rupert. A. Rupert Hall

   . A. Rupert Hall. Isaac Newton: Adventurer in Thought. Cambridge University Press. 1996. 67.

2. Philosophical Transactions of the Royal Society 4: pp. 963–965.
3. Book: Emsley, John. Nature's Building Blocks: an A–Z guide to the elements. Oxford University Press. 2001. 978-0-19-850341-5.
4. 10.1021/ed009p11. The discovery of the elements. II. Elements known to the alchemists. Journal of Chemical Education. 9. 1. 11. 1932. Weeks. Mary Elvira. 1932JChEd...9...11W.
5. De solido intra solidum naturaliter contento dissertationis prodromus.
6. Book: Palmer, Alan. Palmer . Veronica. 1992. The Chronology of British History. Century Ltd. London. 190–191. 0-7126-5616-2.
7. Book: Bartholin, Erasmus. Experimenta crystalli islandici disdiaclastici quibus mira & insolita refractio detegitur. Copenhagen. Daniel Paulli. 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.