Scope and Contents From the File:

Papers regarding payments for work done on behalf of the Board.

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Observations from Captain Cook's last voyage.

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Table of rough calculations of observations; these include records of the time by the watch, the apparent time, and the altitude of the sun and moon. Many entries are checked and marked 'done' or 'correct'.

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Computations relating to the Sun, including those on the Sun's place using Johann Mayer's tables, 11 May 1765 - 29 April 1766, with reference to the obliquity of the ecliptic. There are calculations of the mean time of the transit of the Moon between 31 May 1765 and 28 April 1766, and on the Moon's longitude and latitude using Mayer's tables, 31 May - 19 November 1765. The calculations were made by William Bayly.

Scope and Contents Computations of the positions of the Sun, Moon and planets performed by William Bayly and Reuben Burrow from observations taken when Nathaniel Bliss was Astronomer Royal.1. The Sun's right ascension and declination, clock errors, and longitude and latitude derived from observations and Johann Mayer's tables for 11 May 1765 to 10 May 1767.2. Moon's right ascension and declination, clock errors, and longitude and latitude derived from observations and Mayer's tables for 31 May...

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Daily record of the time by the watch or timekeeper [Kendall’s K1] between 10 December 1779 and 8 September 1780, signed by William Bayly, John Gore and James Burney (or occasionally John Rickman). It includes a note by Bayly on first receiving the watch in June 1776 [RGO 14/61/4: 1r], occasional remarks concerning when it was carried on shore or stoppages, and a brief note on 4 September 1780 of ‘a fire in the cabin’ [RGO 14/61/4: 4v].

Scope and Contents Outgoing correspondence regarding many astronomical and nautical subjects, including accounts with printers, the production of the 'Nautical Almanac', expeditions to Australia, a reward for a method of making glass of a sufficient quality for instruments, the trial of various timepieces and their employment on board Royal Navy vessels, replies to projectors proposing various methods of finding longitude at sea, and instructions for astronomers (including William Gooch on board the Daedalus...

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Regarding the observations made by William Bayly during the voyage of HMS Discovery.

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Concerning a fault in the sextant and requesting a replacement instrument; also concerning his desire to be placed in the land detachment.

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Concerning a replacement sextant and black index glass from Ramsden.

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Sent from HMS Sirius, concerning a timekeeper [K1] received from William Bayly.

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Concerning the rate of the Board of Longitude's watch and the provision of books and instruments.

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The log book of HMS Adventure compiled by W. Bayly during his passage to the South Seas as part of the expedition led by Captain James Cook in HMS Resolution.

Scope and Contents Daily log entries are provided from 1-16 August, followed by summarised entries. On 12 August they passed a reef and small island which they named ‘The Devil’s Girdle’ (map is enclosed). On 14-15 they sighted the island of Maitea [Mehetia], and on 15 August, Wales describes the arrival of local inhabitants in canoes filled with coconuts and fruit which they got in exchange for glass beads [RGO 14/58: 57v]. The following day he records that the ship struck a reef and was eventually moved to...

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This section is inverted in the volume and consists of two series: a daily log of time by the watch [K1], and further observations covering December 1779 to September 1780.

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Daily log of observations from December 1779 to September 1780, showing barometer and thermometer readings (in the morning, at noon, and in the evening), the latitude and longitude, magnetic variation and dip [of the needle], the wind direction and remarks on the weather. The entries also include occasional mention of the location of the two ships on their return journey (travelling via Macau, Pulo Condore [Côn Đảo], Krakatau, and the Cape of Good Hope).

Scope and Contents Tabulated observations made by astronomer William Bayly. These include records of the time by the watch, apparent time, altitudes of the sun, moon and stars, observations of lunar distance, barometer and thermometer readings, estimates of latitude and longitude, and magnetic variation.Occasional remarks on the observations are included: for example, in [RGO 14/61/3: 57r] Bayly records that his instruments were taken on shore at Kamchatka, Russia, where observations were made from 26...

Scope and Contents Observations made on Captain Cook’s third voyage. Includes summarised daily entries providing the date, estimates of latitude and longitude, bearings and distance, variation of the compass, and thermometer readings, along with intermittent entries of astronomical calculations. The ship travelled via Madeira and via Port Praya in St. Iago towards the Cape of Good Hope, anchoring at Table Bay on 10 November 1776 [RGO 14/67: 76v]. There are no entries for December 1776 or January 1777....

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Observations of the going rate of the two watches, first from Nevil Maskelyne before the voyage, and then daily during the voyage with signatures from each of the three keyholders, William Bayly, Captain Tobias Furneaux, and First Lieutenants Joseph Shank or later, Arthur Kempe (sometimes signed instead by James Burney, Peter Fannin, Thomas Woodhouse, Robert Browne, Mr Lanyon, or William Hawksey).

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Observations made on board HMS Adventure during her passage to the South Seas as part of the expedition led by Captain James Cook in HMS Resolution.

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'Account of the going of the two longitude watches on board His Majesty's sloop, the Adventure Captain Furneaux Commander bound towards the South Seas.' Only two pages of the account and the front cover survive. The rating of the watches covers the period 13-29 July 1772.

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Reductions of the Moon's place in comparison with tables, 1763-1771, and calculations by Mr Hollins of the Moon's transit, 1772, by George Gilpin on the Moon's places, 1768-1776, by William Bayly on the Moon, 1766-1775, and by Reuben Burrows on the Moon, 1762-1770. There are also reductions of the Moon's place, 1781-1782, and references to reduced observations, 1783-1792.

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Observations and comparisons during the trials of John Harrison's chronometers (H1, H2, H3 and H4) and Kendall I, with mean solar time, 1766-1767, and the rating of the Royal Observatory transit clock, 1771. The volume is comprised largely of tables of measurements, with some descriptions of how the results were achieved.