INTRODUCTION

The topic of this section is the intricate relationship between technical drawings and knowledge—knowledge those drawings presuppose and/or allude to, invoke, transmit explicitly or implicitly, and/or knowledge, finally, that they help to gain. Besides “literacy” with regard to the different pictorial languages employed, the reading of technical drawings presupposes a spectrum of knowledge of different provenance— technological knowledge regarding both the construction and the working of the depicted device, expertise as regards the practical context of its intended employment, mechanical assumptions or other convictions of how natural things work, and sometimes even mathematical and geometrical knowledge. Accordingly, what these drawings actually convey depends to no little extent on the beholder’s familiarity with the represented object and its whereabouts. They tell different things to experts and nonexperts, to the artisans who construct the device, to other experts who employ it professionally, and to lay people who are interested in it for any reason.

Technical drawings thus constitute a sort of focus where different kinds of knowledge come together and intersect. As such a focus, they radiate, in turn, into different domains of knowledge whose relations to the realm of engineering thus became recognizable. They are therefore mirrors of the intellectual world of early modern engineering if one succeeds in reconstructing the ways in which knowledge was connected with them.

The fact that technical drawings presuppose so much knowledge of all sorts is of course due in part to the limited representational capacity given by their restriction to two dimensions, and to the special semiotic shortcomings of each of the different pictorial languages. Technical drawings thus may appear to imply rather than display and convey knowledge. However, such a view not only would be at odds with the general fact that these drawings were an indispensable means of communicating ideas, proposals, solutions, agreements, and the like. It also would miss a dimension of early modern engineering drawings that is of particular significance in this context. Rather than depending mainly on presupposed knowledge, these drawings contributed essentially to the transformation of implicit, tacit knowledge of the crafts into explicit knowledge. They proved to be a chief means of rendering implicit knowledge explicit.

The chapter by Pamela Long studies the ways in which Francesco di Giorgio Martini and Leonardo da Vinci, two outstanding masters of engineering drawing, promoted the articulation of experiences and knowledge of engineering by means of both drawings and texts. Struggling for clarity, both were innovative in coining new terminology as well as in introducing new pictorial formulas, thereby creating an intertwined whole of pictorial and verbal elements that represented practitioners’ knowledge with combined forces.

The relationship between image and text in illustrated manuscripts and books on engineering issues, which deserves much more attention than could be paid in this volume, is of particular interest with respect to the advantages and shortcomings of the two media as regards the articulation of technological knowledge. Both Giorgio

Martini’s treatises and Leonardo’s notebooks demonstrate impressively that such an articulation and explication cannot be achieved by either of the two media alone. Or, to put it more precisely, they show that the capabilities to spell out technological knowledge each of them possesses can only be exploited fully when each elucidates the other. In this field of knowledge, images explain words no less than words images. Furthermore, the combination of verbal and pictorial means of representation opened up new possibilities for connecting the knowledge of this realm of practice with a variety of branches of learned culture. Pamela Long’s chapter shows that this opportunity was immediately realized and seized by Giorgio Martini and Leonardo, albeit in quite different manners.

The notebooks of Leonardo also testify to a further aspect of the relationship between drawings and knowledge, namely to the employment of drawings for the obtainment of insights—insights of a more theoretical nature as well as more practical ones. When employed in this way as a means of thinking, technical drawings and knowledge exhibit an interplay that is challenging to both the historical actors and the historian who tries to determine which knowledge was tacitly presupposed, which actually represented, and which gained by drawings used for this purpose.

This interplay is the topic of the chapter by Mary Henninger-Voss, who discusses the employment of plans by civilian and military experts in the service of Venice for consulting and deciding on crucial questions of fortification at the turn of the fifteenth century. When applied for these purposes, a fortification plan resembles an iceberg. For what can actually be seen on the plan is only the visible peak, whereas the bulk of information it contains for an expert is as invisible to a nonexpert as the main body of an iceberg under water. Moreover, since specialists of different expertise interact in such decision-making, military architects and military commanders in this case, the whole range of knowledge presupposed by, connected with, and derivable from a fortification plan is not possessed by any of the specialists, but only by an ideal team of experts representing the state of the arts involved. What is obvious in this case holds for the relationship between technical drawings and knowledge in general: it is mediated by the social relations among the actors involved in advanced technological projects.