The Hinkley collection is comprised of an account book and exercise book owned by members of the Hinkley family of Georgetown, Maine, in the mid-18th and early 19th centuries. John Hinkley kept 125 pages of accounts from 1755-1779, Samuel P. Hinkley kept 3 pages of accounts from 1789-1805, and Samuel P. Hinkley recorded 56 pages of information about mathematics and navigational principles. The account book also has 8 pages of religious poetry.
The first 125 pages of John Hinkley's Account Book concern the period between June 1755 and May 1779, though most accounts are dated between 1755 and 1765. His double-entry records pertain to his purchases of chocolate, sugar, corn, meal, rum, molasses, and other foodstuffs, and some reflect his interest in a sawmill. Several aspects of the mill's business are covered, such as providing boards and hauling timber. John Hinkley frequently traded with other members of the Hinkley family, including Josiah Hinkley and Samuel Hinkley. The accounts are followed by 8 pages of religious poetry, with one poem attributed to Betsey Hinkley, and 3 pages of financial accounts that Samuel P. Hinkley sporadically recorded between December 1789 and June 1805.
Samuel P. Hinkley's Exercise Book, dated December 18, 1837, contains 56 pages of nautical navigational problems and exercises. Topics include plane sailing, traverse sailing, parallel sailing, middle latitude sailing, and Mercator sailing, as well as the method of ascertaining latitude by making observations. Hinkley recorded several case studies and accompanying exercises for each sailing method, and the book contains the mathematical calculations used to solve each problem. Some problems, particularly those in the traverse sailing section, are accompanied by tables. The last several pages are copied entries from an unnamed ship's log, originally recorded during a journey between Boston and Madeira in March and April 1824 and during an unspecified voyage in January 1824.