Longitude.- Harrison (John) A Narrative of the Proceedings relative to the Discovery of the Longitude at Sea, first edition, title and 18pp., lacking half-title and final blank, title lightly soiled, library half morocco over cloth, spine lettered in gilt, 8vo, Printed for the Author, and Sold by Mr. Sandby, 1765.

⁂ Extremely rare first edition of Harrison's claim to be awarded the £20,000 'Longitude Prize', as offered in a 1714 Act of Parliament, following the disastrous loss of four Royal Navy warships under the command of Sir Cloudesley Shovell off the Isles of Scilly in 1707.

The second sea trial of Harrison's fourth time-keeper, H4, was made aboard the Tartar on a voyage from Portsmouth to Barbados in 1764. Harrison's son accompanied the voyage and made further refinements to the watch and when it arrived at Barbados the error of the watch was found to be only 43 seconds. Upon returning to England, the Board of Longitude refused to grant the prize to Harrison in full, causing him to publish defences of his watch and its precision. The present work copies letters that the Admiralty sent to Harrison in the preceding years establishing his development of the watch, and concludes with his own memorial. The Board held firm in their refusal to pay out in full for more than nine years and it was not until the intervention of Parliament in 1774 that Harrison received the balance of his reward of £20,000. (See Commander J.B. Hewson, A History of the Practice of Navigation, Glasgow, 1963, pp. 241-245).

Only 4 copies have appeared at auction in the past 40 years: the Streeter copy, Christie's New York 17 April 2007, lot 253; Bloomsbury Auctions, 30 October 2008, lot 192; The Law Society copy, Sotheby's 12 Dec 2012, lot 16; and a copy at Christie's last year. The National Maritime Museum only acquired a copy in 2003.