Hydraulics and the Science of Politics

Leonardo da Vinci was as much engineer, scientist and inventor as he was artist. Many of his drawings are devoted to investigations in optics, topography, and dynamics, and much of his career was spent designing military weapons, architecture and vehicles and working on civil and hydraulic engineering projects.

In 1503 Leonardo da Vinci and Machiavelli began work on a project that they believed would end the threat from Pisa forever. They proposed to divert the Arno river away from Pisa, leaving the city literally high and dry and making Florence a seaport.

The beleaguered Florentine republic approved funds for the project. Leonardo spent the spring and summer drawing a series of stunning "bird's eye" maps of the Arno river and the surrounding landscape. In August 1504, the project began. It was a huge undertaking that posed critical problems for earth removal and directing water flow. Time was of the essence, both for financial and military reasons. The engineer in charge of the project was forced to make cost-cutting measures. Leonardo devised a digging machine to expedite matters and save on labor, but apparently it was never built.

Map of Imola
by Leonardo de Vinci

Leonardo da Vinci
Digging Machine

The result was failure. The diversionary ditches were too shallow and the river did not follow the new course. Efforts to deepen the ditches began, but a storm destroyed the earthworks. What nature left, the Pisans demolished.

According to Roger Masters, who has written a history of the project, "the Arno diversion could be called a magnificent failure. Niccolò and Leonardo tried to control the flow of history and the flow of the river by combining science, technology, and political power. The ambition to use this means to conquer nature, common place today, had never been attempted in quite this way on such a scale."**

The Florentine republic struggled on for a few more years. In 1512, the Spanish army defeated Florence, and Guiliano de Medici siezed power: a most unfortunate turn of events for Machiavelli. In his exile, he turned his attention from the science of engineering to the science of politics with the writing of The Prince.

** Roger D. Masters, Fortune is a River: Leonardo da Vinci and Niccolò Machiavelli's Magnificent Dream to Change the Course of Florentine History (1999), 133. Masters' account of the project can be found on pages 81-133. In 1434, another artist, Brunelleschi, had proposed that Florence divert a river and thereby flood the city of Lucca. This, too, had failed.