 Douglas’s patents attracted attention in the United States, and in 1875 he quit his teaching post to work as superintendent for the Chemical Copper Company, Phoenixville, near Philadelphia, Pennsylvania, then a major center of the chemical industry.In 1883, after the Phoenixville works burned down, he made his last permanent move, to the New York City area to be closer to the financial hub.During this period, he also performed mining consultant work, which took him to mining camps across the far West.