Includes: names and dates of individual manufacturers of navigational instruments, nd; letter from W. J. Hill at the Victoria and Albert Museum, 28 June 1907, re references to Dallond's circle and the Borda Circle in Raper's 'Practice of Navigation and Nautical Astronomy'; notes on the microscopes made by George Adams and his son, by John Neeve, 20 Nov 1920; letter from Adams' son, Francis N[orris] Adams, re the purchase of navigational equipment and instruments from Mrs Gerrard in Liverpool, with her offer to give his father two old books on astronomy and navigation, 26 Apr 1907; letter from Cary Porter Ltd re the age of a quintant in Adams' possession and their Longstaff being the only one they are aware of, 29 Aug 1907; letter from Annie A. Williams at W. Gerrard (Nautical Instrument Maker) in Liverpool, re the provision of missing eye pieces and the possible sale to Adams of a sextant and quadrant (when Francis visits - see previous letter), 25 Apr 1907; letter from M. Gerrard in Liverpool re showing him their stock of old instruments when he is next in Liverpool, 11 Apr 1907; drawings (by Adams) of French Instruments at the Franco British Exhibition, including wood astrolabe by Phillipus Daufrie, nd; two letters from Daniel W. Kettle of Imray, Laurie, Norie and Wilson Ltd, 24 Mar and 6 Apr 1909, re books on navigation and instruments, with printed list of mainly 17th century books and advert re their publication of 'A Complete Set of Nautical Tables with Explanations of Their Use' by J. W. Norie, 1908; letter from Mrs Marriott at the Royal Meteorological Society, 25 Feb 1910, giving advice to Adams on cleaning the mercury in his barometer; list of various navigational instruments with prices (possibly a valuation of Adams' collection?) by 'Hughes'; postcard from Henry Gilbert of Henry Gilbert and Son, bookseller in Southampton, re a copy of 'Newhouse', which is the only copy they have been able to trace, 3 Apr 1912; envelope with drawing and notes on reverse of an octant in ebony with ivory scale by H Duren of New York, nd; letter from Cecil Perham at the Admiralty, 5 Nov 1910, re brigs built for the Royal Navy named 'Espiegle', 'Mutine' and Nautilus and screw sloops constructed in the 1850s and 1860s with those names; letter from George Cockle at A Clarkson and Co (opticians and seller of optical instruments) in London, re dating Adams' Theodolite by A Ross and Co - possibly between 1848 and 1850, when many such instruments were being made - 26 Mar 1912; diagrams of 'sights on Backstaff', with measurements and notes.