(b Lyon, March 2, 1591; d ?Paris, before Oct 8, 1661).
French mathematician, engineer and theorist. He settled at an early age in Paris, where he associated with such intellectuals as Marin Mersenne and Etienne Pascal; the latter’s son, Blaise Pascal, claimed to be Desargues’s disciple and was interested in his geometry of conic sections. Desargues was particularly interested in building techniques that involved the application of scientific knowledge, for example for the draught of chimneys, on which he corresponded with Mersenne and René Descartes, and lifting pumps, the subject of a proposal approved by the city of Paris in 1626, in which a series of fountains to clean the streets was planned. In 1636 he published a treatise on perspective, but he subsequently concentrated on architecture, including a design proposal for the Hôtel de Ville, Lyon. He also became interested in stonecutting (stereotomy), publishing a treatise on the subject in 1640. He used this specialized knowledge when building staircases, which were greatly admired by his contemporaries. Examples (all destr.) include the stairs of the north wing in the courtyard of the château of Vizille, Isère (...