This volume records the proceedings, from 18 June 1859 to 7 June 1862, of this York County (Pa.) Society. There are minutes of the meetings of the organization, formed to promote clear thinking and intelligent discussion on a wide range of topics which are noted for each session, with affirmative and negative arguments. There are lists of members and officers, and the constitution is set forth.

Minutes of meetings, mainly dealing with astronomy; added papers by Jean Paul Grandjean de Fochy and Jean-Jacques Dortous de Mairan.