It is a commonplace that Leonardo was an inventor and engineer, as well as an artist and an astute observer of nature. In light of this reputation and of the many contemporary references to him as an architect and engineer, as well as a devisor of clever theatrical machines and other novelties, it is striking that little evidence survives of his creations beyond the drawings and sketches to be found in his notebooks. Unlike almost every other famous figure in technology, Leonardo’s considerable reputation rests almost entirely on the visual evidence that he himself created, not on what he published or what he actually made or built.
We know little about the intended audiences or the real purposes of many of his technical drawings. The ones that are most commonly reproduced are highly finished renderings of weapons, military constructions, interesting machines, or fanciful devices like the flying machines. But scattered throughout his notebooks, particularly in the smaller ones, are many drawings that are considerably less finished. Many of these are “inventive sketches,” renderings for the purpose of working through possible solutions to technical problems.
An example of such an inventive sketch is in Leonardo’s Manuscript H, fol. 45v (fig. 1). Here he is working out a possible device only in rough form, paying attention to some specific details but neglecting others. This would eventually become an important technical tradition, but in all likelihood it was quite new in his day.
The rendering actually consists of several sketches, all related to the same device. Historians of musical instruments have identified this as the mechanism for a viola organista, and the sketches are among many Leonardo drew to record his ideas for this instrument, now scattered over several manuscripts. It was a “stringed instrument with keyboard in which strings are set into vibration by a mechanical bow” (Winternitz 2). It was a variation on a well-known instrument of Leonardo’s day—what we might most readily refer to as a “hurdy-gurdy.” Leonardo proposed a number of versions of this device, each of them a bit more complicated than those that made their way into practice.
The technical elements of this instrument are less interesting than Leonardo’s intention in sketching it: in essence, he is attempting to invent with his pencil. To a degree this is not so different from his drawing practice for painting, which is documented in hundreds of sketches for rendering everything from clouds to horses to angry old men. It is appropriate that the contemporary term for these sketches was pensieri (thoughts). While examples of medieval engineering drawings survive (the most famous is the sketchbook of Villard de Honnecourt, dating from the first half of the 13th century), nothing is comparable to the quantity and range of inventiveness of Leonardo’s drawings. Moreover, while earlier technical drawings tell us almost nothing about the thought processes of invention and technical speculation of their authors or of their time, Leonardo’s drawings are invaluable for understanding the technological knowledge and thinking process of the early modern period.
In the case of the inventive sketch for the viola organista, Leonardo drew several different aspects of the device. The largest image shows the general layout of the instrument and its series of eight strings set out across a box. A pulley and belt are sketched on the right, running under the strings. Most crucially, eight buttons on the right side of the box are connected to levers that somehow bring the strings in contact with the belt that is moved by the pulley. Leonardo is trying to figure out how to give the player maximum control over the contact made between string and belt–the technical term for the belt is the arcetto, which means bow, and indeed the belt acts as a bow in playing the strings. He wants to provide dynamic control and the means for greater or lesser contact between string and belt in order to allow for louder and softer playing of each note. The drawing at the bottom of the page shows one possible lever-linkage to provide this kind of control.
We have no idea if this—or any of the related drawings—led to the construction of an actual instrument. But this is not really the point of Leonardo’s pensiero. What is more important is the demonstration that the pocket notebooks in which this and similar drawings appear, along with myriad loose sheets of newly available paper, provided a new means of “virtual invention” for the Renaissance technician. We are only now beginning to understand this new means of generating technical novelty.
Fig. 1 Leonardo da Vinci, Manuscrip H, fol. 45v, detail. Bibliotheque de l'Institut de France, Paris.