De_Beaune
# Florimond de Beaune

### Born: 7 Oct 1601 in Blois, France

Died: 18 Aug 1652 in Blois, France

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**Florimond de Beaune** was born in Blois which is in central France, on the Loire River and, at the time de Beaune was born there, it was almost a second capital of France. He was educated in Paris where he went on to study law. After military service he seems to have had little need for earning a living. He became a jurist to the court in Blois and was only an amateur mathematician. He inherited an estate near Blois and he spent a lot of his time on this estate.

His second marriage was one which brought de Beaune a substantial amount of money. It enabled him to build up an extensive library as well as to build himself an observatory. In fact his library contained a good proportion of astronomy works as well as mathematics volumes.

De Beaune produced the first important introduction to Descartes' cartesian geometry. He wrote *Notes brièves* which was published in 1649 as part of the first Latin edition of Descartes' *Géométrie* . De Beaune proved among many results that y = xy + bx, y = -dy + bx, y = bx - x represent hyperbolas, parabolas and ellipses respectively.

Two other papers by de Beaune on algebra appeared as part of the second edition of *Géométrie* . In fact de Beaune and Descartes were good friends and corresponded frequently on mathematical topics. Many of the top scientists French scientists of the time corresponded with de Beaune, for example Mydorge, Billy and Mersenne, and friends visited him to discuss mathematical topics, for example Descartes and Bartholin.

De Beaune was also interested in mechanics and optics and wrote on these topics. However his work in these areas was never published and little is known of his contribution. His interest in optics was related to his interest in astronomy for he worked on grinding lenses, in particular experimenting with non-spherical lenses.

**References (5 books/articles)**

**References elsewhere in this archive:**

Rue de Beaune is in the 7th Arrondissement in Paris. You can see a list of Paris streets named after mathematicians in our archive.

**Other Web sites:**

Rice University, USA

JOC/EFR December 1996