Corrosion data pertaining to a variety of copper-base alloys after two- and four-year exposure to natural environments at New Haven, Connecticut, Brooklyn, New York, and Daytona Beach, Florida are presented. High zinc alloys, cartridge brass alloy B36 (260) and nickel silver alloy B122 (770) experienced substantial decreases in mechanical properties due to “plug type” dezincification and pitting. In addition, the rate of attack on high zinc containing alloys was environment specific. Alloy (619), a copper-aluminum-iron alloy, displayed substantial increases in mechanical properties with time. This is attributed to a long-term low-temperature order-disorder mechanism. The degree of patination was alloy, time, and environment specific. To avoid ambiguity, it is suggested that instantaneous corrosion rate rather than changes in absolute weight loss be used as the criterion for duration of atmospheric testing of copper-base alloys.