This correspondence is with Charles Francis Adams, Jr., Edgar Fahs Smith, and Thomas Sovereign Gates, about undergraduate days at Harvard College, his interest in Harvard, the University of Pennsylvania, and the Wistar Institute. The papers include a list of publications, biographical data, papers on Robert G. LeConte and Daniel Moreau Barringer, a certificate of membership in the Governor Thomas Dudley Family Association, and 25 drawings of crystals and 35 original sketches made to accompany his Harvard thesis, "The Nature and Origin of Deposits of Phosphate of Lime."

This collection contains correspondence, research notes, papers and addresses, memoranda, drafts of letters and papers. These items center on Lingelbach's career at the University of Pennsylvania and at the American Philosophical Society. There is much correspondence with noted historians relating to various topics. His interest in political history and foreign policy, and his participation in national organizations can be seen in such files as the Foreign Policy Association, National Resources Planning Board, and the U.S. War Dept. Committee on Education and Special Training (World War I).