Philippe de La Hire
Who was Philippe de La Hire?
French mathematician and astronomer (1640-1718)
Biographical data adapted from Wikipedia’s article on Philippe de La Hire (CC BY-SA 4.0).
Biography
Philippe de La Hire (18 March 1640 – 21 April 1718) was a French painter, mathematician, astronomer, and architect, so talented that Bernard le Bovier de Fontenelle called him an 'academy unto himself.' Born in Paris, he was the son of the artist Laurent de La Hire and Marguerite Coquin. Growing up with a strong background in the visual arts, he later used these skills in his geometric and scientific work.
In 1660, La Hire went to Venice and spent four years studying painting. Once back in Paris, he was influenced by Girard Desargues, a pioneer in projective geometry, which then guided La Hire's math career. He officially became a master painter on 4 August 1670, and sometimes his paintings were mistaken for those of his son, Jean Nicolas de La Hire, who was both a doctor and a painter. Alongside painting, La Hire became skilled in math and natural science, learning from the Jesuit mathematician Honoré Fabri. Through Fabri, he met the likes of Giovanni Domenico Cassini, Christiaan Huygens, Gottfried Leibniz, and Marin Mersenne.
La Hire joined the French Academy of Sciences in 1678, following Jacques Buot's death. As an astronomer, he worked on tables for the movements of the Sun, Moon, and planets, and created instruments for aerial telescopes. Between 1679 and 1682, he did extensive coastal surveys in France, and in 1683 he helped map France by extending the Paris meridian northward. That same year, he became the chair of mathematics at the Collège Royal, and from 1687, he also taught at the Académie d'architecture, bringing both practical and theoretical knowledge to these places.
His work was published over several decades, covering many mathematical topics. He wrote about graphical methods in 1673, conic sections in 1685, epicycloids in 1694, roulettes in 1702, and conchoids in 1708. His studies on conic sections and epicycloids were greatly influenced by Desargues, whom he was considered the best student of. He also translated the work of Byzantine scholar Manuel Moschopulus on magic squares, introducing it to Europe. La Hire died in Paris on 21 April 1718, having spent nearly his entire life in the city.
Before Fame
Philippe de La Hire grew up in a creative household in Paris, with his father, Laurent de La Hire, being a well-known painter. This environment gave him direct exposure to technique, composition, and the intellectual demands of visual art. This background led him to Venice in 1660, a city known at the time as a major center for painting and artistic training. He spent four years there honing his skills before returning to Paris.
In Paris, he met the geometer Girard Desargues, which shifted his focus towards mathematics. Desargues had developed an advanced approach to projective geometry that clicked with La Hire's understanding of perspective and visual representation. La Hire learned Desargues's methods thoroughly and became his most famous student. This shift from an artist's workshop to the circles of Jesuit mathematicians and European scholars paved the way for his later career in science and teaching.
Key Achievements
- Elected to the French Academy of Sciences in 1678 and made sustained contributions to observational astronomy, including planetary motion tables
- Extended the Paris meridian northward in 1683, contributing to the first accurate cartographic survey of France
- Authored major mathematical works on conic sections, epicycloids, roulettes, and conchoids, several rooted in the projective geometry of Desargues
- Held the chair of mathematics at the Collège Royal from 1683 and taught architecture at the Académie d'architecture from 1687
- Translated Manuel Moschopulus's work on magic squares, introducing the subject to European mathematical readers
Did You Know?
- 01.La Hire's paintings were sometimes mistaken for those of his son Jean Nicolas de La Hire, who pursued both medicine and painting.
- 02.Bernard le Bovier de Fontenelle, the perpetual secretary of the French Academy of Sciences, called La Hire an 'academy unto himself,' a rare tribute reflecting the breadth of his work.
- 03.La Hire translated the Byzantine scholar Manuel Moschopulus's essay on magic squares, one of the earliest efforts to bring this topic into mainstream European mathematical discussion.
- 04.He extended the Paris meridian northward in 1683 as part of a national effort to produce an accurate map of France, a project that ultimately revealed France to be smaller than previously believed.
- 05.La Hire held teaching posts simultaneously at the Collège Royal and the Académie d'architecture, teaching mathematics at both institutions for many years.