Georg Mohr (mathematician)

Jørgen Mohr (Latinized Georg (ius) Mohr) (born April 1, 1640 in Copenhagen , † January 26, 1697 in Kieslingswalde, today Sławnikowice ) was a Danish mathematician . He toured the Netherlands , France and England .

Mohr was born in Copenhagen as the son of the hospital inspector and businessman David Mohrendal. His contribution to geometry consisted in the proof that any geometric construction that can be made with compasses and ruler is also possible with compasses alone ( Mohr-Mascheroni theorem ). He published this proof in the book Euclides Danicus , Amsterdam 1672, which he dedicated to the Danish king in anticipation of financial support. The king wanted to appoint him inspector of the royal shipyard; But that was too much of an obligation for Mohr, because he wanted to live as a free scholar and therefore refused.

Although this book was included in the math bibliographies, no one bothered to review it, and so it went unnoticed for 250 years. Mohr's results were instead ascribed to the Italian Lorenzo Mascheroni , who independently provided the proof a hundred years later (1797). After one of his students found the book in an antiquarian bookshop in Copenhagen, the mathematics professor Johannes Hjelmslev Mohr helped to get his merit recognized in 1928 and published the work as a facsimile in the same year.

Mohr published his Euclides Danicus simultaneously in Danish and Dutch (each with a long subtitle in the corresponding language) instead of, as was to be expected at the time, in Latin . In Latin it would have been accessible to a larger circle of readers.

In 1675, through Henry Oldenburg , he sent a book about pulling roots to Leibniz , who in a letter to Oldenburg the following year commented on it with great praise. Mohr's son (born around 1692) claimed that his father had written three important books on mathematics and philosophy, the third being the counter-exercise to a mathematical treatise Compendium Euclidis Curiosi . Mohr's authorship of the opposite exercise is disputed.

Mohr was friends with Ehrenfried Walther von Tschirnhaus and spent the last years of his life as his guest in Kieslingswalde near Görlitz , where Tschirnhaus wanted to build the nucleus of a Saxon Academy of Sciences .

The Danish mathematicians' competition is named after Georg Mohr.

literature

• Johannes Hjelmslev : Contributions to the biography of Georg Mohr . Copenhagen 1931, Matematisk-fysiske Meddelelser af den Danske Videnskabelige Selskab 11.4. (= mathematical-physical communications of the Danish scientific society 11.4).
• Georg Mohr: Euclides Danicus, Amsterdam 1672. With a foreword by Johannes Hjelmslev and a German translation by Johannes Pal , Copenhagen: Holst 1928

Web links

• Publications by and about Georg Mohr in VD 17 .
• Short biography in the Galileo Project
• John J. O'Connor, Edmund F. Robertson :  Georg Mohr (mathematician). In: MacTutor History of Mathematics archive .