The central files primarily represent organizations who contracted work from the Observatory, or working groups, societies, and conferences to which Linehan contributed his geophysical expertise. Contents are largely correspondence, but also include minutes, reports, product brochures, and conference ephemera. The correspondence includes all incoming correspondence, and frequently a second carbon copy of the outgoing reply (first carbons, on letterhead, were kept separately and are in the Director's correspondence series). Some files by topic are interfiled with organizations. It appears that correspondents were filed in "general," rather than receiving their own file, for one-off correspondence or smaller exchanges that did not result in an ongoing relationship with the Observatory. The central files also include records on the management of the Observatory itself, which are filed under "Weston Observatory".