"Map of the course of the Seine from its source to its mouth, geometrically surveyed in 1747". Large folio (825 x 509 mm) containing eight maps drawn in Indian ink, Indian ink wash and watercolor, mounted on tabs. Full red morocco. Triple right-hand fillet, fleurs-de-lys in the corners; large royal arms on the boards. Eight-rib spine, fleurs-de-lys in the boxes. Large roulette on the edges. Superb set of maps of the course of the Seine, drawn with great finesse, in contemporary colors of perfect freshness. It consists of a general map entitled "Carte du cours de la Seine depuis sa source jusqu'à son embouchure, levée géométriquement en 1747", at a scale of 20,000 toises, measuring 900 X 580 mm for the watercolor drawing, and seven maps at a scale of 6.000 toises, each measuring approximately 920 X 620 mm, representing the course of the Seine divided into seven sections, from the river's mouth near Le Havre to its source near Aisey le Duc, now Aisey-sur-Seine. The sections, all to a scale of 6,000 toises, are roughly as follows: - from Le Havre to Criquebeuf - from Criquebeuf to Rolleboise (near Rosny) - from Rolleboise to Saint-Fargeau, via Paris - from Saint-Fargeau to Nogent and Chaumont, via the Fontainebleau forest - from Chaumont to Bar-sur-Seine, via Troyes, - from Bar to Coulommiers, Châtillon-sur-Seine and Aignay-le-Duc - from Châtillon-sur-Seine to the source on the Langres plateau. None of the eight watercolors is signed or annotated. Provenance: by family tradition, the work may have been a gift from Louis XV to Jean-Baptiste de Machault, comte d'Arnouville (1701-1794). Comptroller General of Finances from 1745 to 1754, replacing Philibert Orry, who had been disgraced by the Marquise de Pompadour. In 1747, Comte d'Arnouville was a close friend of Daniel Charles Trudaine, founder of the École Royale des Ponts et Chaussées. Mid-18th C. Eight maps based on a 1747 survey depicting the journey of the Seine river from source to mouth. Ink, wash and watercolor. Bookbinding bearing the coat of arms of France. The Bibliothèque Nationale de France holds an identical but unbound collection, also presented in eight maps, including a general map, presented as follows by L'Institut Paris-Région: "The whole is based on the Cassini triangulation of Paris, the meridian and its perpendicular being clearly marked in red and intersecting at the location of the Paris Observatory; The maps also show the confluences with the main or secondary tributaries, but with occasional omissions (the Marne-Seine and Marne-Oise confluences in particular, which were nevertheless important for supplying the capital)". Previous maps of the Seine, such as that by Abbé Jean de La Grive, were surveyed by sight. The surveys presented here, bearing the date 1747 and using the Cassini triangulation, suggest a connection with the École des Ponts et Chaussées. 1747: founding of the École des Ponts et Chaussées In 1716, the Regent created a corps of regularly appointed Ponts et Chaussées engineers. Daniel-Charles Trudaine (1703-1769), administrator and intendant of finance, played a major role in the founding of the school. In 1743, he created the Bureau des Dessinateurs du Roi in Paris, responsible for drawing up plans for the kingdom's main roads; the following year, he was appointed head of the Assemblée des Inspecteurs Généraux des Ponts et Chaussées. In 1747, he founded the Ecole Royale des Ponts et Chaussées, and entrusted its management to Jean-Rodolphe Perronnet (1708-1794), a man of the Enlightenment. The school had 50 students... and not a single teacher. Students learn the theory of hydraulics, stereotomy, line drawing, mechanics, geometry, economics, etc., "by self-study" and mutual instruction. Practical training is acquired by participating in multiple campaigns on building sites directed by architects, or by engineers belonging to the Corps des Ingénieurs des Ponts. During their studies, which can last up to 12 years, students must participate in the survey of the Kingdom's map, according to the Cassini methods of geometric triangulation, which requires a perfect knowledge of trigonometry and a mastery of architectural drawing and cartographic surveying.