A relatively early example of a signal book, this copy pre-dates the major changes pioneered by Admiral Popham (Popham's Code) during the Napoleonic Wars and which themselves were printed in limited numbers.

Built at Barnard's Yard, Harwich, in 1756 and rated as a 6th-Rate of 433 tons carrying 20 guns, the Mercury became a victim of the American War of Independance on Christmas Day 1777 when, sailing under the command of Capt. James Montagu from Spuykendevil Creek, New York, her hull was pierced by a cheval de frise blocking the Hudson River. Run aground but too full of water, she capsized and was abandoned.