other chambers had been made (which had been started when Rossi was finishing his), and because the altitude of the laboratory, about 2000 meters, was no longer suitable (the other chambers were in use at about 3000 meters or more). Working at the Fedaia laboratory was nonetheless an excellent “training” for the young physicists who spent there several years - Guerriero and Cresti confirmed it -, as they acquired a good technical and scientific knowledge. Cresti for instance, after leaving the Fedaia laboratory, spent a couple of years in Berkeley, where he brilliantly collaborated within Luis Alvarez’ bubble chamber group (on his second year in Berkeley, he officially became a member of the laboratory staff). This brought him to give interesting contributions on his coming back in Europe,the magnetic field of the earth.[^61] Southern Italy was chosen, as it was at a sufficient low latitude and it offered good technical facilities and satisfying meteorological conditions as well. Two expeditions were thus organized, in 1952 and in 1953, and both were supported by CERN,[^62] which regarded studies on cosmic rays as complementary to experiments with accelerators as, at that time, the high energy particles supplied by cosmic rays could not be artificially generated at all.

The first of these expeditions was carried out from 18$^{th}$ May to 13$^{th}$ July 1952 and thirteen laboratories participated.[^63] The Universities involved were Bristol and Glasgow Universities, Imperial College of London, Padua, Milan, Turin, Genoa, Cagliari and Rome Universities, Göttingen Max Planck Institut, the Ecole Polytechnique of Paris, and the Universities of