Rasmus Bartholin

Erasmus Bartholin ( born August 13, 1625 Roskilde, † November 4, 1698 in Copenhagen) was a Danish scientist.

He described in 1657 the first time the physical characteristics of children with the later named after him Bartholin - Patau syndrome ( trisomy 13) in the medical literature.

Bartholin belonged to an influential family, his father was the polymath Caspar Bartholin the Elder ( 1585-1629 ). From 1648 to 1656 he studied at various European universities like Leiden and Padua the fields of medicine, mathematics, and physics. From 1656 he was professor of mathematics at the University of Copenhagen. His most famous student was Ole Roemer, who also lived with him, and in 1681 his daughter Anne -Marie ( 1663-1694 ) married.

Discovery of the double refraction

His most important discovery he described in his book " Experimenta Crystalli islandici disdiaclastici quibus mira et insolita refractio detegitur, Copenhagen 1669 ". German translation by Karl Mieleitner: experiments with the birefringent Icelandic crystal, which leads to the discovery of a wonderful and extraordinary refraction, Ostwald 's classic belt 205 (1922 ).

It was the first experimental publication in Denmark. On a calcite crystal ( " spar " ) from Iceland, he examined the crystal form, physical, especially optical, and chemical properties.

An extraordinary beam of light hit perpendicular to the crystal surface, was still broken: the double refraction of light. Christiaan Huygens in 1678, a first interpretation of the birefringence by applied the finite light propagation by Roemer. Only when they had understood the polarization of light, succeeded the correct explanation of the birefringence.