Georges Fournier (31 August 1595 – 13 April 1652) was a French Jesuit priest, geographer and mathematician.

Fournier served as a naval military chaplain on a ship of the line,^[1] and acquired a strong knowledge of technical and naval matters.

In 1642, he published the treaty Hydrographie, where he attempted to provide a scientific foundation to the design of ships.^[2][3] At the time, results like Couronne or HMS Sovereign of the Seas were obtained by empirical trials and errors.

He also authored a Treaty of fortifications or military architecture, drawn from the most estimated places of our times, for fortifications,^[4] whose original edition was published in Paris in 1649 by Jean Hénault at the Salle Dauphine of l'ange gardien. Another edition was published in 1668 in Mayence by Louis Bourgeat.^[5]

Georges Fournier taught René Descartes.

In 1642, Fournier published his Commentaires géographiques.^[6] The following year he published in Paris the work which will give him the essential part of his celebrity: the Hydrographie contenant la théorie et la pratique de toutes les parties de la navigation.^[7] Resolutely scientific,^[3] it is the first French maritime encyclopedia.^[8] Dedicated to Louis XIII, it was reprinted many times (1667, 1679, 1973). Geographer, astronomer, hydrographer, mathematician, Fournier took an interest in everything: winds and tides, ports, fishing, maritime trade, shipbuilding, the conduct of officers and the art of command.^[8] The Hydrographie was therefore a first-rate source for the history of the navy during the first half of the seventeenth century, which explains the "magnificent re-edition" of this work in 1973 (Etienne Taillemite).^[6] Georges Fournier also published in 1643 a Traité de la sphere^[8] and in 1644 a Traité de géométrie.^[6] His Traité des fortifications ou Architecture militaire (published in Paris in 1649 ^[9]) was translated into Dutch, Spanish and German.^[4] His works on Euclidean geometry (Paris, 1644 and 1654) were translated into English, and gave rise to three successive editions.^[8] In 1656, posthumously appeared his Asiae nova descriptio (New Description of Asia).^[8] The book was made in collaboration with several jesuit missionaries.^[8]