Topics Technology & Engineering

Thomas Mill Covered Bridge on the Wissahickon

Thomas Mill Covered Bridge over Wissahickon Creek (Picturesque America)

Black-and-white image of a refinery with smokestacks emitting smoke

A Day in the Ma’sh – Oil Refinery

Sewage collection and disposal plan

Plan for the Collection, Purification and Disposal of the Sewage of the City of Philadelphia, 1912