This PhD is a study of hydraulic philosophy—a proposed new name for the branch of early modern natural philosophy concerned with water. Both the production of hydraulic knowledge and its practical application happened in context; the thesis focuses on one of these contexts, early modern European cities. Three case-studies—Augsburg, Florence, and Amsterdam—are approached from an interdisciplinary perspective. In addition to scholarship written by urban historians, historians of science and technology, and art historians, the lens of environmental history has been precious to formulate the research questions and methods underpinning the dissertation.

First, Augsburg, Florence, and Amsterdam are introduced as terraqueous sites, where human bodies interacted with bodies of water: the Lech and Wertach, the Arno, and the Amstel-Ij confluence. Chapter II explores the professional identity and trajectories of the hydraulic experts and practitioners who deployed their knowledge and skills in these three settings. Focusing on specific examples of hydraulic problems or interventions within each city, the following four chapters focus on four ways in which these experts and practitioners interacted with water. Their actions could have great political significance: the Medici (Grand-)Dukes harnessed hydraulics for propoganda aims, whilst municipal authorities in Amsterdam and Augsburg fought (sometimes literally) with their neighbours over borders marked by water. The overarching ambition of early modern hydraulic philosophers, to exert control over water, was represented in the statues of Neptune calming the waves which adorned contemporary fountains, and it was translated in practice with the digging of navigable canals or the reclamation of land. Indeed, the displacement of water was an important manifestation of attempts to control the hydraulic environment: water was drained where it was perceived to be in excess, and pumped where it was thought to be lacking. Measuring the volume, speed, and depth of water also formed part of early modern strategies (and fantasies) of control. Drawing together these four areas of hydraulic action, the dissertation concludes by defining hydraulic philosophy and investigating some of the sources of knowledge and expertise to which its practitioners turned.