Color Diagram of Plan for the Collection, Purification and Disposal of the Sewage of the City of Philadelphia
Bird’s eye view of Delaware River and Philadelphia, about 1840
Commencement of laying the main on the East side of the River, 1871
Henry Disston & Sons Keystone Saw Works
Pennypack Sewage Treatment Works, 1914
Torresdale Conduit work gang, 1906