1. Derek Howse and Norman J. W. Thrower, A Buccaneer's Atlas: Basil Ringrose's South Sea Waggoner (Berkeley and Los Angeles, forthcoming).

2. Royal Warrant, 4 March 1674-1675, copies in PRO State Papers Domestic 29/368, fol. 299, and 44, p. 10.

3. Board of Admiralty to Halley [15 October 1698], PRO ADM. 2/25, pp. 155-156, quoted in full in Norman J. W. Thrower (ed.), The Three Voyages of Edmond Halley in the "Paramore" 1698-1701 (London, 1981).

4. In the early days, these instruments were known variously as "timekeepers," "watches," or "watch machines," often prefixed by the words "marine,'' "box," or ''pocket." The term chronometer began to come into use about 1780.

5. Cook to Secretary of the Admiralty, Table Bay, 22 March 1775, quoted in full in J. C. Beaglehole (ed.), The Journals of Captain Cook (London, 1961), II, 691-693.

6. William Wales and William Bayly, The Original Astronomical Observations Made . . . in the Years 1772, 1773, 1774, and 1775 . . . (London, 1777); and James Cooke [ sic ], James King, and William Bayly, The Original Astronomical Observations Made . . . in the Years 1776, 1777, 1778, 1779, and 1780 . . . (London, 1782).

7. Full instructions for computing lunar observations and all the necessary permanent tables are contained in Tables Requisite to be used with the Nautical Ephemeris for finding the Latitude and Longitude at Sea , 2nd ed., edited by Nevil Maskelyne (London, 1781). The instructions were written by William Wales, astronomer in the Resolution on Cook's second voyage and later master of the Mathematical School at Christ's Hospital.

8. Edmond Halley, "Methodus singularis qua Solis Parallaxis sive distantia à Terra, ope Veneris intra Solem conspiciendae, tuto determinari poterit," Philosophical Transactions of the Royal Society 29 (1716): 454 ff.

9. Halley quoted (without source) in Angus Armitage, Edmond Halley (London and Edinburgh, 1966), p. 104.

10. Derek Howse and Beresford Hutchinson, "The Saga of the Shelton Clocks," Antiquarian Horology (1969): 281-298.

11. "Observations made, by appointment of the Royal Society, at King George's Island in the South Sea; by Mr. Charles Green, formerly Assistant at the Royal Observatory at Greenwich, and Lieut. James Cook, of his Majesty's Ship the Endeavour," Philosophical Transactions of the Royal Society 61 (1771): 398.

12. Howse and Hutchinson, "Saga."