Named after the president of the Pennsylvania Railroad, John Edgar Thomson (1808-74), the steel works in Pittsburgh was opened in 1872 by the Scottish immigrant Andrew Carnegie (1835-1919). Carnegie improved the designs of the original ‘Bessemer’ process and reduced the cost of making steel. Located on the banks of the Monongahela River, the mill could provide cost-effective transportation of iron and steel products via the River.
When Pennell visited the Carnegie Institute in 1908 he “found these works and this view of them on a trolley ride out of Pittsburgh. They group themselves under their canopy of smoke as finely as any in the world… how much more impressive is a row of blast furnaces, oil wells, and coal breakers, than trees!”.