properties of dioptric instruments and made elementary representation of the theory and its applications. His work contains a detailed description of the geometric dioptrics for uncentered systems. He provided a greater generality as previously found in the telescopic system treatments, with less emphasis on applications. In the second main sections, the results obtained are applied to optical instruments. The magnification, field of view, and the brightness of the instrument were dealt with in great detail. The field denned as the author of the cone opening angle, the tip of the first main points of the lens, and its base formed by the parts of the object in view, will possess the same brightness. The eye is not treated. Memorials The city of Turin honored the contributions that Ferraris made to science. A general committee proposed an addition to the Royal Industrial Museum of Turin with a permanent monument commemorating his scientific and industrial achievements. Additionally, an avenue was named in honor of Ferraris. In January 2021 Ferraris was honored by the IEEE Milestones program for his contribution to "the technological innovation and excellence for the benefit of humanity", namely for his “Rotating Fields and Early Induction Motors, 1885-1888”. The according plaque carries the inscription:Galileo Ferraris, professor at the Italian Industrial Museum (now Polytechnic) of Turin, conceived and demonstrated the principle of the rotating magnetic field. Ferraris’ field, produced by two stationary coils with perpendicular axes, was driven by alternating currents phase-shifted by 90 degrees. Ferraris also constructed prototypes of two-phase AC motors. Rotating fields, polyphase currents, and their application to induction motors had a fundamental role in the electrification of the world. Publications Sulle differenze di fase delle correnti e sulla dissipazione di energia nei trasformatori, by Prof. Galileo Ferraris (Turin, 1887). Online texts : vol. 1 vol. 2 vol. 3 References Further reading External links B. Bowers, "Scanning our past from London: Galileo Ferraris and alternating current" in Proceedings of the IEEE, vol. 89, no. 5, pp. 790–792, May 2001, doi: 10.1109/5.929656. M. Mitolo and M. Tartaglia, "Galileo Farraris - A Life Dedicated to the Electric Sciences [History]" in IEEE Industry Applications Magazine, vol. 22, no. 5, pp. 8–11, Sept.-Oct. 2016, doi: 10.1109/MIAS.2016.2574223. Raffaella Gobbo, L'archivio di Galileo Ferraris, Roma, Amministrazione degli Archivi di Stato, 2005. Estratto da: Rassegna degli Archivi di Stato, n. s., 1 (2005), n. 1-2, 9–169 p. Chronology of Galileo Ferarris, 24-33 p. Museo Ferraris