Fairmount Park topographical map, showing East Park Reservoir, 1872
Thomas Mill Covered Bridge over Wissahickon Creek (Picturesque America)
Wingohocking Sewer across Penn St.
Images from “A Day in the Ma’sh” by Maurice F. Egan, Scribner’s Monthly, July 1881
Frankford Creek: Sad History of an Urban Stream title page
Schuylkill River Hydrographical Survey 1861-66 by H. P. M. Birkinbine
Duplex Pumping Engine, Belmont Works