1737-1809 architects biography bridges civilization designandconstruction ecology economicdevelopment environmentalaspects environmentalconditions environmentaldegradation environmentalhealth environmentaljustice gardens geography guidebooks hazardouswastesites healthandhygiene history humangeography ironandsteelbridges middleclass minorities paine pennsylvania politicalandsocialviewspaine politicalaspects politicalscientists revolutionaries schuylkillriver socialaspects socialconditions thomas unitedstates