Characterization of Early 20th Century Measurement Instruments: A Heritage Approach

A conservation campaign is currently underway, at Politecnico di Torino, to preserve a significant collection of measurement instruments and devices from the Department of Physics and the Advanced School of Electronics Laboratory, originally established by Galileo Ferraris in 1888. The collection comprises teaching and research apparatus used between the 1920s and 1960s, including voltmeters, ammeters, galvanometers, valve and battery testers, and other related equipment. The ongoing conservation effort utilizes non-invasive, in situ analytical techniques such as portable X-ray fluorescence (XRF), Raman spectroscopy, and multiband photogrammetry. These methods have enabled detailed examination of the materials and their degradation processes without compromising the integrity of the artifacts. Preliminary analyses have revealed a variety of corrosion morphologies, attributable to the use of different base metals, iron, copper, silver alloys and to variable environmental conditions over time. Galvanic corrosion is a frequent finding, particularly in areas where Cu-based and Fe-based alloys or gilded components, are in direct contact. Cross-polarized and Ultraviolet-Induced Luminescence Photogrammetry are being employed to generate detailed 3D models of the instruments, supporting both documentation and future conservation planning.