A book not so far mentioned in the chat about ancient longitude is The Marine Chronometer, its History and Development, by Rupert T. Gould. It was published in 1923 and reissued by the Holland Press, London in 1960, reprinted 1971, which is the date of my copy. No ISBN number given.
Gould, a retired naval officer who worked at the National Maritime Museum in Greenwich, England, is not sufficiently noticed in this field. In 1935 he delivered a paper on Harrison's chronometers to the Society for Nautical Research. Before him were all five of Harrison's chronometers together with the duplicate of no. 4 made by Kendall and used by Captain Cook. They had all been restored by Gould, some from a ruinous condition and were all going. By the way, the earth rotates once a day and the moon goes round the earth once a lunar month so the longitude by chronometer is of necessity thirty times as accurate as the longitude by lunar distance. Frank -- Frank Evans
