Radio engineer and manufacturer. Correspondence, diaries, blueprints, sketches, plans, notebooks, company files, photographs, reports, clippings, and printed matter largely related to Eastham’s career as a radio engineer and as head of the General Radio Company, but also to his avocation of collecting early maps and atlases.

Handwritten student manuscripts pertaining to mathematics education collected by professors Nerida F. Ellerton and M. A. Clements. Includes Ellerton and Clements's detailed descriptions of each manuscript.

Aviator, navigator, naturalist, and inventor. Research notes, subject files, and indexes used in preparation of Gatty's books, Raft Book: Lore of the Sea and Sky (1943) and Nature Is Your Guide (1958), together with correspondence, charts, maps, drawings, bibliographies, clippings, and other papers relating to navigation.

Navigation researcher and consulting engineer. Correspondence, writings, notes, lectures, ship’s papers, problem sets, calculations, maps, and other papers chiefly relating to Mixter’s contributions to the study of navigation.

Official correspondence and administrative records of offices of the Naval Observatory, located in Washington, D.C., including of the superintendent, Nautical Almanac, librarian, and the superintendent of compasses and instruments, concerning activities of the observatory and tracing its development from its origin in the Depot of Charts and Instruments.