Bartholin E
Bartholin, Erasmus
ACHIEVEMENT(S): Double refraction
NICKNAME/ALIAS: Bartholinus (Latin)
DATE/PLACE OF BIRTH: 13 August 1625, at Roskilde, Denmark
DATE/PLACE/AGE AT DEATH: 4 November 1698, in Copenhagen, Denmark. Aged 73
DISCIPLINE: Physicist
FIELD: Optics
LANGUAGE: Danish
PARENTS: Caspar Bartholin (1585-1629) and Anna Fincke, married 1612
SIBLINGS: Five brothers, including Thomas (1616-80; anatomist)
SPOUSE: ?
CHILDREN: ?
EDUCATION: Copenhagen Latin School; University of Copenhagen, 1642-46;
University of Leiden, 1646-50; University of Padua, 1654
MAJOR WORK: 'Experiments on Icelandic Spar', 1671
LIFE AND TIMES: Erasmus Bartholin was born in 1625 at Roskilde, Denmark, the
fifth of the six sons of the theologian and anatomist Caspar Bartholin, a professor at the University of Copenhagen, and Anna Fincke. One of Bartholin's elder brothers, Thomas Bartholin*, became a famous anatomist , and the six children grew up in an distinguished cultured environment, in spite of the death of their father when Erasmus was only four years old.
Bartholin was initially educated by private tutors before attending the Latin school in Copenhagen. He then entered the University of Copenhagen in 1642, where he received his B.A. two years later, and in 1645 he moved to the University of Leyden. He remained in Leiden for several years as a student of mathematics and medicine, and in 1651 he continued his mathematical studies in France, England and Italy. He eventually arrived in Padua, where in 1654 he was awarded his medical (M.D.) degree.
Bartholin spent two more years travelling and studying in Italy (1654-56), before returning to Copenhagen, now aged 31, where he was appointed professor of mathematics at the University of Copenhagen.
The following year (1657) he was transferred to a chair of medicine, and became a full professor of medicine in 1671. He retained his post at the university until his death in 1698, serving also as dean of the faculty of medicine, librarian, and rector, and was also appointed Royal Physician and privy
councillor.
Bartholin was famous in his time as a doctor, although he published few
medical works, in particular for his introduction of cinchona bark to Denmark, and also for his contributions to a journal founded and edited by Thomas. His most important mathematical works were his edition of Frans Van Schooten's 'Introduction to the geometry of Descartes' and his translation into Latin of Heliodorus of Larissa's 'Optics' (1657). In the same year he also published an essay entitled "The Study of the Danish Language."
Bartholin was also interested in astronomy and observed the comets of 1665
with the assistance of the astronomer Roemer*, which he published as 'De cometis anni 1664 et 1665 opusculum' (1665). Around the same time, and again
assisted by Romer, he was asked by Frederick III of Denmark to prepare for
publication the collected manuscript observations of Brahe*, which the king had bought from Kepler.
Bartholin's most important work was his study of crystals of transparent Icelandic spar (now known as a form of calcite), collected by an expedition sent from Denmark to the east coast of Iceland in 1668. Experimenting on the crystals, Bartholin discovered both their perfect cleavage and that images observed through them doubled.
He also noticed that when the crystal was rotated, one image remained stationary while the other rotated with the crystal. Realising that the light passing through the calcite was being split into two rays (a phenomenon now known as double refraction), he called the stationary image the "ordinary beam" and the moving image the "extraordinary beam".
Bartholin wrote up his findings in detail as 'Experimenta crystalli Islandici disdiaclastici quibus mira & insolita refractio detegitur' (1669), a copy of which was sent to Oldenburg* of the Royal Society.
Although Bartholin himself was unable to explain double refraction, it was recognized as a serious contradiction to Newton's* optical theories, and proved to be of great theoretical interest to both Christiaan Huyghens* (who in 1678, by studying the same variety of crystal, discovered the laws of double refraction) and Newton. Bartholin continued his studies of crystallography during the 1670s, frequently collaborating with Stensen* ('Steno'), who was then royal anatomist at Copenhagen.
Bartholin remained professor medicine at the University of Copenhagen until his death in 1698, at the age of 73. His studies of Icelandic spar were continued by, among others, the French mineralogist RJ Hauy* in the late 18th century and the English paleobotanist Nicol* in the 19th century. Iceland spar is now used in polarizing prisms such as the Nicol prisms and in polarizing microscopes, polariscopes, and other optical instruments
ASSESSMENT: Best remembered for his discovery of the double refraction of light
through a crystal of Iceland spar.
EXTRA CONNECTIONS: None
ONELINER: Erasmus Bartholin, discoverer of double refraction
BIBLIOGRAPHY:
DSB, EB
Buchwald, Jed Z. & Kurt Moeller Pedersen, "Introduction", in Erasmus
Bartholin, Experiments on Bifrefringent Icelandic Crystal, trans, Thomas
Archibald, Copenhagen, 1991