‘Explaining’ themselves: The Barrington papers, the board of longitude, and the fate of John Harrison

In 2003 the National Maritime Museum acquired a group of documents compiled by Viscount Barrington while he was a commissioner on the Board of Longitude. These focus on the year 1765, when the Board sought two Acts from Parliament to explain its decisions and to extend its powers. Since its establishment in 1714, the Board had considered two main solutions to the problem of finding longitude at sea: the clocks of John Harrison and the lunar distance method of Tobias Meyer. Trials of both had shown that the Board needed to clarify what constituted a real solution. Barrington's papers revolve around a speech that he gave to the House of Commons during the passage of the Acts, and include accounts, correspondence and notes. These not only reveal the internal workings of the Board but also make clear for the first time the extent to which the commissioners were explaining their decisions and their existence to a sceptical Parliament.