The stamp depicted on the left was issued by Ascension Island in 1979 to commemorate the 200th anniversary of the death of the great British explorer, cartographer, navigator and Royal Navy Captain, James Cook.
In both of the stamp sets below, James Cook’s chronometer appears. It is, specifically, a marine chronometer made by the man who invented the marine chronometer in 1730. He was Englishman John Harrison (1693-1776). This was the first of a series of chronometers that enabled accurate marine navigation.
2018 marked the 250th anniversary of James Cook’s death and Papua New Guinea produced the above minisheet in commemoration.
Getting back to John Harrison, the importance of whose invention cannot be overestimated. Great Britain released the stamps shown below in 1993 which show in detail Harrison’s Marine Timekeeper No.4. manufactured in 1764.