‎"MONGE, (GASPARD). - FOUNDING DESCRIPTIVE GEOMETRY.‎
‎Mémoire sur les Développées, les Rayons de Courbure, et les Différens Genres D'Inflexions des Courbes a double Courbure‎

‎(Paris, Moutard, 1785). 4to. Extracted from ""Mémoires fe Mathematique et de Physique, Présentés à l'Academie des Sciences par divers Savans"", Tome X. Pp. 511-550 a. 2 folded engraved plates. Clean and fine.‎

Reference : 44970

‎First appearance of this importent paper by the ""greatest geometer of the century"" in which he solves some main problems in coordinate geometry, especially he introduced the ""distant formula"" for three dimensions, years before it was used by Lagrange. He laid the foundation of a completely new branch of mathematics, known as descriptive geometry. The paper was delivered already in 1771, but not published until 1785. ""His first important original work was ""Memoire sur les développées, les rayons de courbure et différents genres d inflexions des courbes á double courbure"" He published an extract from it in June 1769 in the Journal encycyclop´matiques, and in October 1770 he finished a more complete version that he read before the Academie des Sciences in August 1771"" the latter, however, was not published until 1785 Mémoires de mathématiques et de physique présentés á ’Academic par divers scavanns. By then some of the most important ideas in the memoir no longer seemed so original, because Monge had employed them in other works published in the intervening years. Nevertheless, this memoir is of exceptional interest, for it presents most of the new conceptions that Monge developed in his later works, as well as his very personal method of exposition, which combined pure geometry, analytic geometry, and infinitesimal calculus.""(DSB).‎