Engineering--Pennsylvania--Philadelphia 3 Engineering--Problems, exercises, etc 3 Engineers--19th century 2 Engineers--Pennsylvania--Philadelphia--19th century 2 Fire Fighters--Pennsylvania--Philadelphia--19th century 2 Fire Stations--Pennsylvania--Philadelphia--19th century 2 Fire engines and equipment--Pennsylvania--Philadelphia--19th century 2 more ... Railroad engineering 2 Science and Engineering--Notes 2 Science and engineering--Pennsylvania--Philadelphia--20th century 2 Spouses--Correspondence--19th century 2 United States. Army of the Potomac 2 United States. Army. Corps of Engineers--History--19th century 2 Ambulances--Pennsylvania--Philadelphia 1 American Lithuanian Engineers and Architects Association 1 Bessemer process 1 Business--History--Pennsylvania--Philadelphia--20th century 1 Canals and railroads--19th century 1 Centennial Exhibition (1876 : Philadelphia, Pa.) 1 Civil Engineering 1 Clubs and Associations--Philadelphia--20th century 1 Craniology--19th century 1 Delaware & Schuylkill Canal 1 Employment--Job Seeking 1 Engineering firms--United States 1 Engineering proceedings 1 Engineering--Education 1 Engineering--Pennsylvania 1 Engineering--Social aspects--United States 1 Engineering--Societies, etc 1 Engineers--Scotland--18th century 1 Ephemera 1 Ethnology--19th century 1 Farmers--Scotland--18th century 1 Fire engines and equipment--Philadelphia--18th century 1 Genealogy 1 Gettysburg, Battle of, Gettysburg, Pa., 1863 1 Household Accounts--19th century 1 Hydrographic surveying--Mississippi River 1 Immigrants, Germans--Philadelphia--19th century 1 less ...