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Papers of James Bradley and Nathaniel Bliss, 1700 - 1804

Reference Code: GBR/0180/RGO 3

Scope and Contents

The collection contains a complete series of transit observations for Bradley's term as Astronomer Royal, supplemented by notes, calculations, tables and correspondence, with a smaller set of observations and other papers relating to Bliss. The observation ledgers for both Astronomer Royals feature the handwriting of Charles Green, who was Bradley's assistant and continued in his post under Bliss. The papers are written mainly in English, but also include Latin and one item in Italian.


  • 1700 - 1804


Conditions Governing Access

Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (

Biographical / Historical

James Bradley (1692-1762) was born in Sherborne, Gloucestershire, and educated at Northleach grammar school and Balliol College, Oxford (B.A., 1714; M.A., 1717). He developed an interest in astronomy under the influence of his uncle James Pound, and assisted him in making observations. Two of Bradley's own observations were published in 'Philosophical Transactions of the Royal Society' in 1718, and later that year he became a fellow of the society. He was ordained in 1719, and became Vicar of Bridstow in Monmouthshire.

From 1719 to 1721, Bradley and Pound attempted to determine the parallax of the Sun from observations of Mars at opposition, and Bradley produced new tables for the phenomena of Jupiter's satellites. In 1721 he was appointed to the Savilian Chair of Astronomy at Oxford and resigned his church livings. Following a period of observational work at Kew and Wanstead, he presented a paper to the Royal Society in 1729 announcing the discovery of the 'aberration of light', an apparent shift in the position of stars caused by the movement of the Earth around the sun, and used his theory to calculate the speed of light.

Bradley was appointed Astronomer Royal in 1742. He began a rigorous observing programme in which he continued his research into the aberration of light. In 1748 he published a paper announcing the discovery of the nutation of the Earth, a nodding of the axis of rotation caused by the gravitational pull of the Moon. He was lecturer in experimental philosophy at Oxford, 1729-1760, and a member of the council of the Royal Society, 1752-1762. Bradley died at Chalford, Gloucestershire, on 13 July 1762. His observations were published in two volumes, 1798 and 1805.

Nathaniel Bliss (1700-1764) was born on 28 November 1700. He attended Pembroke College, Oxford (B.A., 1720; M.A., 1723), and became Rector of St Ebbe's, Oxford, in 1736. In 1742 he was appointed Savilian Professor of Geometry and Fellow of the Royal Society. That year he began to correspond with James Bradley, who he later assisted at the Royal Observatory. He replaced Bradley for the observation of the transit of Venus on 6 June 1761, and succeeded him as Astronomer Royal in 1762. Bliss died on 2 September 1764. The observations made under his supervision were published in 1805.


43 volume(s) : paper

10 folder(s)

1 envelope(s) (1 envelope)

Language of Materials




Other Finding Aids

A word-processed handlist is available in the Manuscripts Reading Room.

Immediate Source of Acquisition

Bradley's observations were removed by his executors after his death, and became the property of his daughter. They passed from Miss Bradley to her uncle, the Revd Samuel Peach, and then to his son, John Peach, whose younger brother Samuel presented them to Oxford University in 1776. For many years the papers were in the hands of Clarendon Press as it prepared them for publication. They were returned to Greenwich by Oxford University in 1861. Bliss' observations were presented to the Observatory by his executors in 1768. RGO 3/45 was presented by the Radcliffe Trustees in 1934. RGO 3/46 was a later addition, source unknown.

Existence and Location of Copies

RGO 36/1 contains microfilms of RGO 3/1-14, 30-45. Consult the hard copy catalogue of this series (available in the Manuscripts Reading Room) to obtain the classmark in use at the time of filming.


This description was created by Robert Steiner, Department of Manuscripts and University Archives. The biographical histories were compiled with reference to the entry on James Bradley in Leslie Stephen and Sidney Lee, eds, 'Dictionary of National Biography', Vol. II (London, 1908), pp. 1074-1079, and the entry on Nathaniel Bliss in ibid., pp. 682-683. It was emended in January 2009 by Zoe A. Rees.


Bradley, James, and Bliss, Nathaniel

Finding aid date

2005-11-01 12:39:04+00:00

Includes index.

Repository Details

Part of the Cambridge University Library Repository

Cambridge University Library
West Road
Cambridge CB3 9DR United Kingdom

The UK Archival Thesaurus has been integrated with our catalogue, thanks to Kings College London and the AIM25 project for their support with this.