Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.1): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

KQtf General Remarks. 1. Variation. Captain Fitz-Roy's observations are so well distributed over the southern hemisphere, that a good view of the changes which the variation is undergoing throughout its meridians may be obtained by comparing his determinations with those of earlier observers at the same stations. The following table has been formed for the purpose of exhibiting such a comparison at all those stations where materials for it exist ; and I may here remark how much such comparisons are facilitated by the valuable collection of early observations contained in the Appendix to the Magnetismus der Erde. Cape of Good Hope. Observer. Davis Keeling . Lev'decker Mathews La Caiile Wales Wales Bligh . . . Dentrecasteaux Freycinet Fitz-Roy Date. Variation. 1605 1609 1675 1724 1752 177-2 1775 1788 1792 1818 1836 o o. o. 16. 19. 20. 21. 23. 24. 26. 28. St. Helena. Davis H alley . Halley . Mathews Wales Hunter . Macdonald Krusenstern Fitz-Roy 1610 1677 1691 1724 1775 1789 1796 1806 1836 /• o. 1. 7- 12. 15. 15. 17. 18. 30 E. 12 W. 28 W. 22 W. oW. 96 W. 14 W. 16 w. 30 w. 31 w. 30 w. 13 E. 40 E. o W. 30 W. 18 W. 30 W. 48 W. 18 W. 00 W. Rio de Janeiro. Cook Hunter . Freycinet Rumker . Ermaii Fitz-Roy 1768 1787 1820 l82i 1830 1836 7- 6. 2. 3. 2. 34 E. 12 E. 54 E. 21 E. 10 E. 00 E. Falkland Islands. Observer. Freycinet Duperrey Fitz-Roy . Date. Variation. 1820 1822 1833 o 19- 19. 19. Port Famine. Wallis . Carteret . Fitz-Roy. 1766 22. 1766 22. 1831 23. C0NCEP91ON. La Perouse .. 1786 B. Hall .. .. 1821 Duperrey .. 1823 Fitz-Roy.. .. 1835 Valparaiso. Don G.Juan .. i744 Vancouver . 1 793 Lutke .. .. 1827 Fitz-Roy.. .. 1835 Callao. 15. 15. 16. 16. 12. 14- 15. 15. Ulloa Duperrey Fitz-Roy. 1740 9- 1823 9. 1835 10. 26 E. 07 E. 00 E. 30 E 22 E. 00 E. 15 E. 30 E. 16 E. 48 E. 30 E, 49 E. 00 E. 18 E. 02 E. 30 E. 36 E. Galapagos Islands. Vancouver B. Hall .. Fitz-Roy.. 1794 8. 00 E. 1821 8. 20 E. 1835 9. 30 E.