Rasmus Bartholin

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Rasmus Bartholin
Rasmus Bartholin.jpg
Rasmus Bartholin
Born13 August 1625
Died4 November 1698 (aged 73)
Known forDouble refraction of a light ray
Scientific career

Rasmus Bartholin (/bɑːrˈtlɪn, ˈbɑːrtəlɪn/; Latinized: Erasmus Bartholinus; 13 August 1625 – 4 November 1698) was a Danish physician and grammarian.


Bartholin was born in Roskilde. He was the son of Caspar Bartholin the Elder (1585–1629) and Anna Fincke, daughter of the mathematician Thomas Fincke.[1]

As part of his studies, he travelled in Europe for ten years. He stayed in the Netherlands, England, France and Italy. In 1647, he took a Master's degree at the University of Copenhagen. In 1654, he received a Doctoral degree at the University of Padua.

He was a Professor at the University of Copenhagen, first in Geometry, later in Medicine. He was also dean of the faculty of medicine, librarian, and rector.[2] He wrote, in Latin, the first grammar of the Danish language, the 1657 De studio lingvæ danicæ.

Rasmus Bartholin is remembered especially for his discovery (1669) of the double refraction of a light ray by Iceland spar (calcite).[3] He published an accurate description of the phenomenon, but since the physical nature of light was poorly understood at the time, he was unable to explain it.[4] It was only after Thomas Young proposed the wave theory of light, c. 1801 that an explanation became possible.


He was a younger brother of Thomas Bartholin (1616–1680).[5]


  1. ^ "Fincke, Thomas, 1561-1656". Dansk biografisk Lexikon. Retrieved 1 August 2019.
  2. ^ Erasmus Bartholin School of Mathematics and Statistics. University of St Andrews, Scotland
  3. ^ Erasmus Bartholin, Experimenta crystalli islandici disdiaclastici quibus mira & insolita refractio detegitur (Copenhagen ("Hafniæ"), Denmark: 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.
  4. ^ "Erasmus Bartholin | Danish physician and physicist". Encyclopedia Britannica.
  5. ^ V. Meisen. "Thomas Bartholin". Dansk Biografisk Leksikon Gyldendal. Retrieved 1 August 2019.

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