Lithuania. In the course of his travels he encountered Paul Wurz, occasioning the correspondence that resulted in Blondel's first publication, a mathematical pamphlet entitled Epistola ad P. W. [Paulum Wurzium], which discussed the breaking resistance of beams. Blondel demonstrates that a mathematical proof of Galileo, allowing the cross-section of a beam to be parabolically shaped such that its weight was reduced by one third, only applied to cantilevered beams and did not apply to the specified aim, a beam supported at both ends, for which a semicircular or elliptical shape would apply. Some of these questions were taken up again in 1673, when he published his Résolution des quatre principaux problèmes d'Architecture. In 1659, on a voyage to Constantinople he saw an aqueduct "in a place that one calls Belgrade, which by its grandeur, its height and the magnificence of its structure, cedes nothing to that of the Pont du Gard." That same year he was posted as diplomatic resident to Copenhagen, and post he filled until 1663, when he was recalled to France to become a conseiller d'État. The following year, 1664, Colbert named him Ingénieur du Roy pour la Marine, which occasioned his supervision of harbour fortifications in Normandy (Cherbourg, Le Havre), in Brittany and in the Antillies (Martinique, Guadeloupe, Saint-Domingue), where he witnessed at first hand the prodigious effects of a hurricane at the island of Saint-Christophe, and where he found the materials for numerous memoires presented to the Académie des Sciences. Quatremère de Quincy reported that Blondel's talents for architecture were first tested in 1665, in building the royal corderie (ropewalk) at Rochefort. Blondel was also put in charge of constructing the Roman bridge at Saintes. In 1669, Blondel was admitted to the Académie des Sciences as a geometer (cartographer). That year, in the course of a trip to London in the company of Jean-Baptiste du Hamel, secretary of the Académie, he witnessed an unsuccessful blood transfusion effected by the Royal Society in hopes of curing a madman, with the thought that the human passions were transmitted in the blood. That same year he was commissioned with urbanization projects for the embellishment of Paris, notably the reconstruction of the Porte Saint-Denis and the Porte Saint-Bernard, and the plan for the city's expansion, which he accomplished with the collaboration of the architect Pierre Bullet. On 31 December 1671, the King named Blondel Director and Professor of the