containing propositions for describing geometrically the catenaria, and the extradosses of all curves, so that their several parts and their piers may equilibrate : also concerning bridges, and the flying buttresses of cathedrals : to which are added, in illustration, sections of Trinity Church, Ely; King's College Chapel, Cambridge; Westminster Abbey; Salisbury, Ely, Lincoln, York, and Peterborough Cathedrals