By 1889, the U.S. output of steel exceeded that of the UK, and Carnegie owned a large part of it. Carnegie's empire grew to include the J. Edgar Thomson Steel Works in Braddock, (named for John Edgar Thomson, Carnegie's former boss and president of the Pennsylvania Railroad), Pittsburgh Bessemer Steel Works, the Lucy Furnaces, the Union Iron Mills, the Union Mill (Wilson, Walker & County), the Keystone Bridge Works, the Hartman Steel Works, the Frick Coke Company, and the Scotia ore mines. Carnegie, through Keystone, supplied the steel for and owned shares in the landmark Eads Bridge project across the Mississippi River at St. Louis, Missouri (completed 1874). This project was an important proof-of-concept for steel technology, which marked the opening of a new steel market.