On the way to Bessemer

The Bessemer process was developed by the English inventor Sir Henry Bessemer (1813-98) and patented in 1855. It was the first inexpensive industrial process for the mass production of steel. In this view of the mill, which Pennell has named after Bessemer, furnaces and chimneys obscure the hills of Pittsburgh. Steamers pass beneath the steel bridges beside railway tracks and trolley lines.