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. 



Date. 



Variation. 



Davis 



1605 



0 

 0. 



30 E. 



Keeling . . 



1609 



0. 



12 W. 



Leydecker 



1675 



8. 



28 w. 



Mathews 



1724 



16. 



22 W. 



La Caille 



1752 



19. 



oW. 



Wales 



1772 



20, 



26 W. 



Wales 



1775 



21, 



14 w. 



Bligh . . . . 



1788 



23. 



16 w. 



Dentrecasteaux 



1792 



24. 



30 w. 



Freycinet 



1818 



26. 



31 w. 



Fitz- Roy 



1836 



28. 



30 w. 



St. Helena. 



Davis 

 Halley . . 

 Halley . . 

 Mathews 

 Wales 

 Hunter . . 

 Macdonald 

 Krusen stern 

 Fitz- Roy 



1610 

 1677 

 1691 

 1724 



1775 

 1789 

 1796 

 1806 

 1836 



7. 13 E. 



0. 40 E. 



1. o W. 



30 W. 



18 w. 

 30 w. 

 48 w. 

 18 w. 

 00 W. 



7. 

 12. 



15. 

 15. 

 17. 



18. 



Rio DE Janeiro. 



Cook 

 Hunter . 

 Freycinet 

 Rumker . 

 Erman 

 Fitz- Roy 



1768 

 1787 

 1820 

 1821 

 1830 

 1836 



7. 34 E. 



6. 12 E. 



2. 54 E. 



3. 21 E. 

 2. 10 E. 

 2. 00 E. 



Falkland Islands. 



Observer. Date. Variation. 



Freycinet 

 Duperrey 

 Fitz- Roy . 



o / 



1820 19. 26 E. 

 1822 19. 07 E. 

 1833 19. 00 E. 



Port Famine 



.. .. 1766 

 , 1766 

 . 1831 



Wallis . . 

 Carteret . . 

 Fitz-Roy .. 



C0NCEP910N. 



La Perouse 1786 15. 



B. Hall .. .. 1821 15. 



Duperrey .. 1823 16. 



Fitz-Roy.. 1835 16. 



Valparaiso. 



Don G.Juan 1744 12. 



Vancouver 1793 14. 



Liitke .. .. 1827 15. 



Fitz-Roy.. .. 1835 15. 



30 E 

 22 E. 

 00 E. 



15 E. 

 30 E. 



16 E. 

 48 E. 



30 E. 

 49 E. 

 00 E. 

 18 E, 



Callao. 



UUoa 

 Duperrey 

 Fitz-Roy .. 



1740 9. 02 E. 

 1823 9. 30 E. 

 1835 10. 36 E. 



Galapagos Islands. 



Vancouver . . 1 794 8 

 B. Hall .. 

 Fitz-Roy.. 



1794 «. 00 E. 

 1821 8. 20 E. 

 1835 9. 30 E. 



