Leonardo was associated with engineering projects in all his life. In 1482 he offered his abilities in a letter to Lodovico Sforza, in ten points he presented himself as a designer and inventor of war machines - of movable bridges, battering rams, scaling ladders, mines, explosive devices, cannon and guns, naval arms, tunnels, armoured vehicles, catapults, projectiles and other things - as well as an architect of public and private buildings and water pipes. In his final years in France he dealt with architectural projects as well as hydrological projects intended for several French rivers.

Leonardo dealt with themes that had been considered by engineers before him and usually also written about in treatises. Nonetheless, Leonardo the engineer remains an exciting figure, for his method of developing machines is one that can still be called exemplary today.

He made a systematic study of the flying movements of birds and investigated the anatomy of the wing. He also studied general forms of movement in nature and understood that motion was the result of force and counterforce. He studied the element of air, and conducted extensive studies of water. As a canal engineer, he built canals, bridges and locks and therefore had to understand the effects of forces such as whirlpools, surface eddies and rates of flow, as these had an effect on the direction of flow. Comparative phenomena can also be observed in the air. The science of winds, which Leonardo studied by observing water, helped him the understand air thermals.

Preview	Picture Data	Info
	Crossbow Machine 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Giant Crossbow 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Assault chariot with scythes c. 1485 Silverpoint, pen and ink on paper, 210 x 292 mm Biblioteca Reale, Turin
	Multi Barrel Gun 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Siege Defenses 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Siege Defenses 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Cannon foundry 1487 Pen and ink on paper Royal Library, Windsor
	Study of water c. 1513 Pen and ink on paper, 154 x 216 mm Royal Library, Windsor
	Studies of water 1509-11 Pen and ink on paper, 290 x 202 mm Royal Library, Windsor
	Drawings of Water Lifting Devices 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Canal bridge c. 1495 Pen and ink on paper, 27 x 20 cm Biblioteca Ambrosiana, Milan
	Flying machine c. 1487 Metalpoint, pen and ink on paper, 235 x 176 mm Institut de France, Paris
	Drawing of a flying machine c. 1485 Pen and ink on paper, 23 x 16 cm Bibliothèque de l'Institut de France, Paris
	Device for Making Sequins 1480-82 Drawing Biblioteca Ambrosiana, Milan
	Skis with which one can walk on water (detail) c. 1480 Metalpoint, pen and ink on paper Biblioteca Ambrosiana, Milan
	Automobile 1478-80 Metalpoint, pen and brush on paper, 27 x 20 cm Biblioteca Ambrosiana, Milan
	Spring Device - Manuscript Museo del Prado, Madrid