Joseph Priestley. The noted English scientist, discoverer of oxygen, and Unitarian theologian lived in Northumberland, 1794 to 1804. His home and laboratory along the river are now a Priestley memorial and museum. Duke St. (PA 147) at 10th St., Northumberland, PA by Pennsylvania Historical and Museum Commission Colour: blue Wikimedia: Flickr: Google Streetview OpenStreetMap See also... Spudgun67 on Wikimedia Commons Peter Hughes on Flickr Peter Hughes on Flickr Open Plaques on Flickr Cy Evans on Wikimedia Commons Peter Hughes on Flickr Spudgun67 on Wikimedia Commons David Grimshaw on Geograph User:Ruhrfisch on Wikimedia Commons Seo Mise on Geograph warrington.civsoc on Flickr PD 1.0 Spudgun67 on Wikimedia Commons