The Sienese engineers
The manuscripts by 15th-century Italian engineers show their attempts to apply the concept of perpetual motion to operating machines. In his De ingeneis, the Sienese Mariano di Jacopo, known as Taccola (1381-ca. 1458), describes the overbalanced wheel with articulated arms depicted by Honnecourt and in Arab manuscripts. He also provides diagrams of overbalanced wheels and of what appears to be a wheel with moving arms and buckets for excavation. Another Sienese engineer, Francesco di Giorgio (1439-1501), explores the topic of a recirculation mill. He draws a hydraulic motor connected to a piston pump or an Archimedes’ screw that was supposed to be powered by the force of the falling water raised by the motor itself.
Munich, Bayerische Staatsbibliothek, Cod. Lat. Monacensis 197 II, f. 58r
Munich, Bayerische Staatsbibliothek, Codex Latinus Monacensis 197, pt. II, f. 69v
Florence, Biblioteca Medicea Laurenziana. Ms. Ashburnham 361, f. 36r