INTRODUCTION

In the period when the decisive steps toward classical mechanics were made (15001700), technical drawings played an important role in mediating between practical and theoretical knowledge. This much-neglected function of early modern engineering drawings is the topic of the last section of this volume.

Reflections and inquiries of a more theoretical nature were not at all beyond the horizon of early modern engineering. Design processes are themselves reflection processes of a specific kind and cannot be cordoned off clearly from reflections on issues connected with the working of machines that properly could be called theoretical. As already discussed at several places in this volume, particularly in the chapters by Marcus Popplow, David McGee, and Pamela Long, technical drawings played an important role in design processes. Naturally, the possibilities and restrictions that such drawings provide for and impose on these designing reflections mark the power and limits of drawings as means for general reflections about machines as well as their working principles. With respect to the use of drawings for such more theoretical purposes, the advantages and shortcomings of specific pictorial languages are of particular significance. It is not by chance that, as in the case of Leonardo’s notebooks, drawings that doubtless served such general reflections often switched from a pictorial style of representation to the diagrammatic one that was common in treatises on mechanics. In this way, such reflections could make use of geometrical demonstrations and proofs that served as chief means of reasoning in early modern mechanics. However, these diagrams, whatever their advantages over more pictorial representations, shared some of the principal limits characteristic of engineers’ models on paper. Their representational potency was overtaxed if one tried to represent on one and the same diagram both the spatial relations of a device and physical quantities such as its mass or forces acting upon it.

These limits of engineering drawings as means of theoretical reflections on machines, however, must not obscure another significant role these drawings played as mediators between practical and theoretical mechanics. As is now almost generally acknowledged, early modern mechanics developed along with the technological innovations of this period and hardly can be understood without this background. Almost all of the pioneers of preclassic mechanics were either engineers themselves, Tartaglia being probably the most prominent instance of such a theorizing engineer, or were occupied occasionally with engineering issues and tasks, as was the case with Galileo. The new technology provided a wealth of new subtle objects whose investigation advanced the understanding of the patterns and laws of the natural potencies of which these devices made use. Yet to become truly familiar with the advanced technology of the age, even in highly developed regions like the Padua-Venice area, personal experiences with real machinery of some sort must be complemented by knowledge gained through representations of machines, either three-dimensional models or technical drawings, and knowledge acquired elsewhere through the study of tracts. It even might be possible that, for investigations of machines in a theoretical

Perspective, drawings and other models were of even greater significance than real machines.

The main topic of Michael Mahoney’s chapter is an exceptionally instructive instance of the power and limits of technical drawings for mediating between theoretical and practical mechanics. His example concerns diagrams by Christian Huygens that were at the interface between practical and theoretical mechanics in a twofold way. First, some of them served the communication between Huygens and Thuret, the Parisian clock-maker who translated Huygens’ concept of an Horologium Oscil-latorium into a working design, thereby proving how differently they could be read by a theoretician and by a practitioner. Second, some of them are highly intricate compounds of different layers of diagrams that represent entities from completely different worlds—from the practical world of machines, from the multidimensional world of physics, and from the ethereal world of mathematics. These diagrams demonstrate to which extremity technical drawings in combination with geometrical diagrams could be pushed when used in theoretical investigations and, at the same time, how impracticable this means of representation became for this employment.