A commonplace book of draft treatises and notes on solar theory, optics and other subjects, in Flamsteed's hand, dated December 1674 to September 1691, but possibly later, 136 folios: 'De motu Solis correcto: Lectura 1a' (1r-13r); 'Meditatio de Methodo percommoda inaequalitates orbitae solaris investigandi' ('Meditation on a most useful method of determining the inequalities of the solar orbit'), unfinished (17r-18r); drafts 'Of Rayes of light transmitted', '...reflected' and '... refracted' (21v-44r, 55r-61r); a copy of an extract of a letter to Richard Wroe about finding the date of Easter, 1675 (45r-46r); and 'Inquiries Concerneing the ... Longitude' (48r-53r). The notes include definitions of astronomical terms (105v-110r); observations of Jupiter by Johann Hevelius, 1675-1688 (116r-118r); notes relating to Burstow, including a list of books sent down there, 1685 (119v-122r); notes on Thames tides (124r-125v); rough calculations (127v-136r); Biblical quotations; and payments to a woman for her clothes (136v).