Mathematical Treasure: Ismael Boulliau on Geometry and Astronomy

Ismaël Boulliau (1605–1694) was a 17th-century French Catholic priest who worked as a librarian for most of his career. He was a strong advocate for Copernicus’s and Kepler's theories, and he was a correspondent with Isaac Newton. He had made astronomical observations with his father; as an adult he theorized on the inverse square law for gravitational attraction, which would eventually be formalized by Newton.

Boulliau’s works on mathematics included Exercitationes geometricæ tres (Three Geometrical Exercises), published in 1647, which concerned inscribed and circumscribed figures, conic sections, and porisms.

A full digitization of the copy owned by the National Library of Naples is available from GoogleBooks.

In 1657 he published a book on the geometry of spirals, De lineis spiralibus: Demonstrationes novae.

A full digitization of the copy owned by the public library in Lyon is available from GoogleBooks.

Boulliau published Opus novum ad arithmeticam infinitorum in 1682. This was an information-dense text.

A full digitization of the copy owned by the Bavarian State Library is available from GoogleBooks.

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