Great piece of western history. Wells Fargo Express cover to Safety Nitro Powder Company with scarce Gold Hill postmark. Great trifecta of cool. Red oval Wells Fargo backstamp dated 1884 and red wax seal. Safety Nitro was located at 430 California Street in San Francisco. Safety Nitro was formed in 1880 and merged in 1892 with Giant Powder to form the Giant Powder Company, Consolidated. Giant needed a plant away from Berkeley after the many explosions at the Judson plant at Fleming Point. Safety Nitro’s plant was on San Pablo Bay, four miles west of Pinole, also the site of the California Powder Works (History of the Explosives Industry in America, 1927, Van Gelder). View pictures of the cover for condition.