 Until the issue for 1924, the time argument for Greenwich Mean Time was counted from 0h starting at Greenwich mean noon (on the civil day with the same number), and starting with the issue for 1925 the commencement point of the time argument was changed so that 0h became midnight at the beginning of the civil day with the relevant number, to coincide for the future with the civil reckoning.During parts of the period 1767–1959, separate subsidiary titles dedicated to navigation were also published