"The Ashburton Treaty had been settled with the United States, for the boundary between Canada and the State of Maine, and one of its conditions was, that a straight line about 65 miles in length should be drawn through dense woods, connecting definite points. It soon appeared that this could scarcely be done except by astronomical operations. Lord Canning, Under Secretary of the Foreign Office, requested me to nominate two astronomers to undertake the work. I strongly recommended that Military Officers should carry out the work, and Capt. Robinson and Lieut. Pipon were detached for this service. On Mar. 1st they took lodgings at Greenwich, and worked at the Observatory every day and night through the month. My detailed astronomical instructions to them were drawn out on Mar. 29th. I prepared all the necessary skeleton forms, &c., and looked to their scientific equipment in every way. The result will be given in 1844. "Of private history: In January I went to Dover with my wife to see the blasting of a cliff there: we also visited Sir J. Herschel at Hawkhurst. In April I was at Playford, on a visit to Arthur Biddell. On Apr. 9th my daughter Annot was born. From July 22nd to August 25th I was travelling in the South of Ireland, chiefly to see Valencia and consider the question of determining its longitude: during this journey I visited Lord Rosse at Birr Castle, and returned to Weymouth, where my family were staying at the time. In October I visited Cambridge, and in December I was again at Playford." The journey to Cambridge (Oct. 24th to 27th) was apparently in order to be present on the occasion of the Queen's visit there on the 25th: the following letter relating to it was written to his wife: SEDGWICK'S ROOMS, TRINITY COLLEGE, CAMBRIDGE. _1843, Oct. 26, Thursday_.