Credit: Library of Congress
By the 1870s, William Frishmuth, who had emigrated from Germany to Philadelphia in 1855, had developed a chemical reduction process for the production of small amounts of aluminum. Frishmuth displayed an aluminum surveyor's transit at the 1876 Centennial Exhibition in Philadelphia, and cast the aluminum cap placed atop the Washington Monument in 1884. Harper's Magazine considered the event of sufficient importance to place this illustration on the cover of its December 20, 1884 issue.
