What was significant about this mechanical taxonomy, explains Galluzzi, was that it represented “the gradual emergence of criteria for describing machines by type and category based on the identification of common principles.” Based on his study of these devices, Francesco was able to design new machines far more advanced in mechanical design than Taccola’s.
It was Leonardo da Vinci (1452-1519), of course, who initiated the most ambitious expansion in the role of the artist-engineer, progressing from astute observer to inventor to theoretician. In his notebooks, which combined text and illustration, we see what are truly “thought experiments” in all kinds of areas, Galluzzi says. He analyzed, in almost anatomical detail, the “elements of machines” and combined them in innovative ways, such as in the complex spring motor. Drawing played a key role in this effort: it allowed Leonardo skillfully to dissect mechanical devices and reassemble them using the full range of illustration techniques he had mastered. His drawing of Brunelleschi’s revolving crane is one such example-in fact, the model currently on exhibit was built according to the specifications found in Leonardo’s sketches.
As his interests extended to other subjects-optics, hydrology, geology, and ultimately the human body-his studies were informed by his fascination with machines. For instance, Leonardo presents the human body, says Galluzzi, “as a remarkable ensemble of mechanical devices.” He sketches muscles, joints, and the motions of limbs in terms of wedges, axles, fulcrums, levers, and counterlevers-“the outcome,” Galluzzi notes, “of a bold attempt at unifying nature under a small number of universal laws.”
And again it is drawing that provides a new dimension to these investigations. In Leonardo’s view, drawing was indispensable if a machine or body or phenomenon was to be truly and wholly known. “O writer, with what letters will you describe with such perfection all that is depicted here in drawing?” asked Leonardo; “… don’t try to convey to the ears those things that pertain to the eyes, because the painter will be vastly better at it than you … . Therefore it is necessary to draw as well as to describe.”
What the Renaissance artist-engineers devised, Adams explains, was a way of working through the medium of drawing. “Leonardo comments on his copy of Francesco di Giorgio’s treatise,” he says, “and Francesco makes notes on his copy of Taccola. There is an internal commentary on drawing that is taking place, an internal discourse. There was nothing like this in earlier periods. What we have in the Renaissance are drawings about ideas, drawings about experiments.”
Leonardo was the grand master of this form of experimentation, Adams adds: “He just drew and drew and drew and created more and more ideas. And though relatively few of these ideas were actually realized, what’s important is that he kept developing the language. And it’s this language that becomes the basis for scientific experimentation and technological development in the centuries that follow.”
Today we take for granted the scientist’s and engineer’s notebook filled with questions, notes, quotes, drawings, scribbles, and erasures. But it was the Renaissance artist-engineers who invented the form. We see in their texts and drawings the complex interplay between practice and theory, and the overlapping aims of art, science, and technology. “Depicting nature, understanding nature, and modifying nature were all intertwined,” says George Bugliarello, former president of Polytechnic University, “and artists, engineers, and scientists alike were all engaged essentially as researchers.” In the work of the fifteenth century artist-engineer, he says, it is difficult to determine where the engineering begins and the science or art ends.
The Renaissance represented a rejection of constraints and an embrace of artistry that contemporary engineers would do well to emulate. As Eugene Ferguson observed in Engineering and the Mind’s Eye, “The conversion of an idea to an artifact is a complex and subtle process that will always be far closer to art than to science.” What “Invention in the Age of Leonardo” presents so strikingly is a reminder of how inspiring the blurring of those boundaries can be.