The Zaccheus Brown notebook (175 pages) contains information on arithmetic, sailing and navigation, and surveying, as well as a log of the Phoenix's voyage from New Jersey to the Virgin Islands in 1789.
The first 112 pages, compiled from 1782-1783, are comprised of information about mathematics and sailing and contain a brief ship's log. Mathematical subjects include square and cube roots, geometry, and plane trigonometry; Brown copied and solved mathematical problems, which are often illustrated with diagrams. Instructions for aiming cannons appear in the section about trigonometry. Brown also described sailing methods such as plane, traverse, oblique, Mercator, parallel, middle latitude, and current sailing, as well writing instructions for turning a ship windward and for determining location. The parts of the volume concerning sailing also contain problems, diagrams, and an example of a "Plane Chart" and "Mercator's Chart." The Mercator's chart shows the locations of islands in the northern Caribbean Sea. The notebook's other subjects include the compass, calculating the phases of the Moon, and the Gregorian calendar. A final section pertains to surveying.
Zaccheus Brown's notebook also contains logs concerning the voyage of the Endeavour (9 pages) and the schooner Phoenix (58 pages). The Endeavour log, attributed to "L. H," notes the ship's journey "from the Cape" in late June and early July 1783. The Phoenix log details Brown's voyage from June 17, 1789-September 1, 1789 from Salem, New Jersey, to the Virgin Islands and back to Virginia. Some of Brown's daily entries about his voyage on the Phoenix include charts recording the ship's course and position, along with additional remarks on wind speed and direction. Brown occasionally discussed other aspects of his voyage, such as the pidgin language spoken by the ship's Dutch crew and his premonitions after bad weather and delays. He also described the port and the island of Saint Thomas, a Dutch colony (currently part of the United States Virgin Islands).
The volume contains illustrations of a man in the sun, a compass rose, and a fish and man; the latter drawings are flourishes on the heading for the section of the book on cube roots. The back endpaper includes a table of angles related to navigation.
