Lorenzo della Volpaia founded a dynasty of craftsmen who worked in Florence and Venice until the late sixteenth century. The della Volpaias were highly regarded clockmakers and scientific-instrument makers. Lorenzo had contacts with Leonardo da Vinci, who mentions the water meter built for Bernardo Rucellai.
Lorenzo's boldest undertaking was the planetary clock, of which he produced two different versions. The second, completed in 1510, was installed in the Sala dei Gigli [Hall of Lilies] in the Palazzo Vecchio. The device was already missing at the end of the sixteenth century. The main purpose of planetary clocks is not direct timekeeping but rather to display the positions of the heavenly bodies relative to the Earth, in order to exactly determine astrological influences. The construction of such clocks required a considerable knowledge of astronomy, accurate computations, and machining skills.
The notebooks of the della Volpaias contain the information needed to reconstruct Lorenzo's lost clock, a project carried out by the Museo di Storia della Scienza of Florence in 1994. The clock has a finely decorated dial with a fixed hour circle bearing the signs of the Zodiac. The lesser disk, which rotates clockwise, has six openings. In five of these, the five planets then known—Saturn, Jupiter, Venus, Mars, and Mercury—rotate counter-clockwise. The sixth opening contains the Dragon, which displays the lunar nodes and eclipses. At the center, two superposed disks show the phases and ages of the Moon and the index of the Sun. The dial wheelwork, of unprecedented complexity, is arranged vertically on parallel planes. There are also a pair of globes—one celestial, the other terrestrial—and a sophisticated chime system. A single weight-driven motor drives the clock's incredibly varied movements.
Lorenzo della Volpaia, 1510 / Replica (Florence, 1994)