Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

24 MEMOEANDUM. " Sir ; Admiralty Office, 11th November 1831, " With reference to the order which my Lords Commission- ers of the Admiralty have this day addressed to you, I am commanded by their lordships to transmit to you a memoran- dum, to be shown by you to any senior officer who may fall in with you, while you are employed on the duties pointed out in the above order. " I am, Sir, &c. (Signed) " Geo. Elliot." " To Commander Fitz-Roy, ' Beagle' surveying vessel, Plymouth.'" " Admiralty Office, 11th November 1831. " Memorandum. " My Lords Commissioners of the Admiralty having ordered Commander Fitz-Roy, of his Majesty's surveying vessel the ' Beao-le,' to make surveys of various parts of the South Ame- rican station, it is their lordships' direction that no senior officer who may fall in with Commander Fitz-Roy, while he is employed in the above important duties, do divert him therefrom, or in any way interfere with him, or take from him, on any account, any of his instruments or chronometers. (Signed) " Geo. Elliot." " Memorandum. " A considerable difference still exists in the longitude of Rio de Janeiro, as determined by Captains King, Beechey, and Foster, on the one hand, and Captain W. F. Owen, Baron Roussin, and the Portuguese astronomers, on the other ; and as all our meridian distances in South America are measured from thence, it becomes a matter of importance to decide be- tween these conflicting authorities. Few vessels will have ever left this country with a better set of chronometers, both public and private, than the Beagle ; and if her voyage be made in short stages, in order to detect the changes which take place in all chronometers during a continuous increase of tempera- ture, it will probably enable us to reduce that difference within limits too small to be of much import in our future conclusions.