The Christopher Mason letter book (143 pages, 124 letters) contains copied incoming and outgoing letters of a British navy officer who fought in America during the Revolutionary War. The volume covers communications from three of Mason's commands: the HMS Delaware (1780), the HMS Quebec (1781-1783), and the HMS Zealous (1794-1795). The volume contains 79 incoming letters, an index for the 1794-1795 incoming items, and 43 outgoing letters. These include Mason's contact with the British Navy Board and with fellow officers serving during the Revolution.
The inscription on the front cover of the book reads: "Letters Relating to the War in America. Movements of Ships & Men, Information regarding the Enemy, Convoys, Lists of Rebel Ships, Victualling & Refitting, Exchange of Prisoners, List of Prizes taken, ETC."
Pages 1-49 and 1a-22a cover Mason's time on board the Delaware while it was stationed in Halifax Harbor and during its patrol of the coast of Maine (April 3-December 24, 1780). These letters contain details on the naval operations in the northern theater of the war. Topics include the conditions and activities of the British army and navy in Nova Scotia, the French and American navies, the Americans' use of whale boats to attack the British scouting ships, coal mining in Nova Scotia, and conflicts near Spanish River (Sydney, Nova Scotia), Penobscot River, St. Lawrence, and the Bay of Fundy.
- June 12, 1780, page 1a: Warren 's acknowledgement of control of the British fleet from Captain Cosby.
- June 20, 1780, page 4a: News that the Nautilus was burned by the rebels.
- July 9, 1780, page 37: Intelligence on conflicts with the French Fleet and rumors that George Washington had disappeared from the army for three weeks and might not return.
- July 20, 1780, pages 14-19: A long letter from Peter Aplin describing enemy activities near Halifax. This item contains a list of rebel ships in the area and was delivered by two Native Americans.
- July 27, 1780, page 13: Intelligence on the American ships the America, Thorn, and Brutus.
- August 9, 1780, page 9a and August 11, 1780, page 24: A description of the condition of the Delaware, which had many rotten boards and was infested with rats. On September 16, 1780, page 13a, Warren "smoked" the ship to kill the rats.
- September 11, 1780, page 48: News that General Horatio Gates was defeated in North Carolina by Cornwallis.
- September 16, 1780, pages 14a-15a: A list of officers serving under Mason in Nova Scotia (name, office, ship, and reason for promotion), and a list of prizes seized or destroyed under Mason.
Pages 58-60 and 29a-34a document Warren's service patrolling the Delaware River and the North River (Hudson River) in the HMS Quebec (October 27, 1781-September 19, 1783). These communications are primarily between Warren and the admiralty office.
- October 27, 1781, page 30a: A list of convoy ships under Mason.
- July 30, 1782, page 58: Complaints against Lieutenant Piers of the Argo for "Molesting the Inhabitants, turning cattle into their grounds, taking their wood without paying for it &ca. &ca. &ca."
- December 23, 1782, page 31a: An account of taking the American ship the South Carolina and bringing the ship to New York.
- January 2, 1783, page 32a: Rumors that peace has been settled and concern by Warren that this will decrease the value of the prize ship South Carolina.
Pages 62-88 and 41a-55a cover Warren's time when he was patrolling the British Channel and while he was stationed at Spithead and Plymouth in the HMS Zealous (May 17, 1794-April 24, 1795). Communications are largely to and from officers in the Admiralty Office, Navy Office, Office of Ordnance, and the Vitualling Office. These letters concern supplying ships with ammunition, cannons, and other provisions; disciplining and discharging sailors, and securing bounty owed to his crew on board the Zealous.
- November 21, 1794, page 44a: A report that failure to follow anchoring signals at sea caused damages to ships.
- January 9, 1795, page 51a and January 15, 1783, page 83: Reports of Greek sailors replacing sick seamen on Warren's ship.