 Cook's log used the nautical date, which, during the 18th century, assigned the same date to all ship's events from noon to noon, first p.m. and then a.m. That nautical date began twelve hours before the midnight beginning of the like-named civil date.Furthermore, Cook did not adjust his nautical date to account for circumnavigation of the globe until he had travelled a full 360° relative to the longitude of his home British port, either toward the east or west.Because he travelled west on his first voyage, this a.m. nautical date was the morning of a civil date 14 hours slow relative to his home port (port−14h).