


Thomas Mill Covered Bridge over Wissahickon Creek (Picturesque America)

Centre Square Water Works, Frederick Graff, Sr. Plans, 1799

Centre Square Water Works, Latrobe Plans, 1799

PWD Drinking Water Treatment diagram

Steam engine drawing, Frederick Graff Sr., 1815

Wood truss drawbridge, Orthodox Street over Frankford Creek, 1899 [Detail]

Bridge Street Draw, July 26, 1897

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

State Street pipeline construction, 1904

Electric Pump Installations at Lardner’s Point Pumping Station
