This Report deals essentially with the results of field-tests on the atmospheric corrosion of non-ferrous metals and alloys. Sixteen different metals were tested, including copper, arsenical copper, cadmium-copper, two tin bronzes, aluminium bronze, three brasses, nickel, pure and commercial zinc, a nickel-chromium alloy, two copper-nickel alloys and lead. The metals were exposed, in the form both of plates and of wire, at five experimental stations, set up, respectively, at Cardington (Bedford), Bournville, Wakefield, Birmingham, and Southport, which were selected as being representative of various types of atmosphere. The corrosion was measured by three independent methods. These were based on determinations of the increase in weight of specimens exposed in Stevenson screens, of the increase in the electrical resistance of fully exposed specimens and of the loss in weight of plate specimens, also under conditions of complete exposure. In the case of the resistance tests, the effect of corrosion on the breaking load of the wires was also determined. Whenever possible, the tests were made on at least two duplicate specimens. The main field tests were conducted over a period of one year, from June, 1927, to May, 1928. The observations have been supplemented by other tests conducted in the London atmosphere. Efforts were made to correlate the results of the main tests with the local atmospheric pollution data at each of the experimental stations.