Perspective with Nature: Daniele Barbaro, Jean François Niceron and a Device of Giovanni Battista Vimercati

In 1565 Giovanni Battista Vimercati published in Venice a treatise on gnomonics in which there is a device for making copies of sundials. This tool must be exposed under the Sun and contains: two styli; a drawing; and a blank sheet on which to draw the new delineation. The way it works is simple. While one stylus retraces the drawing with its shadow, the other projects an equal shadow that makes the user able to draw a copy. Vimercati did not explain the geometric rules underlying his device and did not indicate relations with other scientific or practical fields. A few years later, Barbaro will explain the link between perspective and gnomonics, just mentioning the tool of Vimercati. In his treatise Barbaro demonstrates also why we should consider the rays of light like physical elements that embody the geometric process of vision. In the following century Jean Fraçois Niceron understood the true potential of Vimercati’s tool by projecting the shadow of a stylus on all kind of surfaces. The Minim friar used this gnomonic device to obtain anamorphoses. So, Vimercati’s tool epitomizes the physical connection between light and visual rays, acting as a bridge between sundials and vision.