Cook's longitudes in this voyage are all given as west of Greenwich, not
divided into east and west, as is usual at this day. The latter system
again has only been adopted universally since his time.

Though Cook himself gives, at the beginning of the Journal, a note of the
method of reckoning days adopted, it may not be amiss to give further
explanation here.

It was the usual custom on board ships to keep what was known as Ship
time--i.e., the day began at noon BEFORE the civil reckoning, in which
the day commences at midnight. Thus, while January 1st, as ordinarily
reckoned, is from midnight to midnight, in ship time it began at noon on
December 31st and ended at noon January 1st, this period being called
January 1st. Hence the peculiarity all through the Journal of the p.m.
coming before the a.m. It results that any events recorded as occurring
in the p.m. of January 1st in the log, would, if translated into the
ordinary system, be given as happening in the p.m. of December 31st;
while occurrences in the a.m. of January 1st would be equally in the a.m.
of January 1st in both systems.

This puzzling mode of keeping the day at sea continued to a late period,
and was common to seamen of all nations.

The astronomical day, again, begins at noon AFTER the midnight at which
the civil day begins, and hence is a whole day later than the ship's day.
This does not enter into Cook's Journal, but one of the logs of the
Endeavour, extant, that of Mr. Green the astronomer, was kept in this
time, and the events of say Thursday, June 24th, of Cook's Journal, are
therein given as happening on Wednesday, June 23rd. These differences of
reckoning have been a fertile source of confusion in dates in many