The contents of a guardbook of letters received by Flamsteed, 162 folios. The dorses have often been used by Flamsteed for rough calculations. The correspondents include several people connected with Flamsteed's living of Burstow or with other property. The volume includes a printed notice advertising William Whiston's experiment to find the speed of light and sound (150r).

The correspondents are Stephen Gray; [Dr] John Arbuthnot; 'E.B.' [probably to Mrs Flamsteed, telling the story of a ghost seen by Mrs Bargrave]; John Gisborne, Derby (senior and junior?); H. Greatorex, Derbyshire; Richard Tomkinson, Derbyshire and Staffordshire; William Hawkins; Isaac Hawkins, Nottinghamshire; Dr Th. Hill, Peterborough; Henry Jacob; [Dr] White Kennett, Lowthorp; Sir Jonas Moore; Samuel Molyneux; the Earl of Orkney; James Pound; Francis Peck, Burstow; Mat[thew] Randall, Chichester; Captain Henry Stanyan (including letters to Mrs Flamsteed); Robert Stafford; Thomas Smith; Samuel Spateman; John Smith, tenant, Staffordshire; Stephen Thornton, Kent; Francis Thompson, London; Lieutenant Henry Thomas; Richard Waller (for the Royal Society); Matthew Wright; R. Walsh; John Witty; William [Lloyd, Bishop of] Worcester; and George Young.