1st. South dip increasing.
annually.annually.
St. Helena1754 to 17756,9′Cape of Good Hope1775 to 18366,6
Do.1775 to 18366,5 Mauritius1754 to 18241,3
Cape of Good Hope1751 to 17757,2 Do.1824 to 18360,8

To this division also belongs Ascension; but as the north end of the needle dips at that island, the change is north dip diminishing, instead of south dip increasing.

Ascension1754 to 17756,3 annually.
Do.1775 to 18367,2 —
2d. South dip decreasing.
New Zealand1824 to 18351,2 annually.[[211]]
3d. South dip increasing.
Otaheite1775 to 18360,5 annually.
4th. South dip decreasing.
annually.annually.
Lima and Callao1710 to 17990,4′Tierra del Fuego1774 to 18288,0
Do1799 to 18354,9 Falkland Islands1820 to 18348,2
Valparaiso1794 to 183510,0 Sta Catharina1822 to 18278,4
Concepçion1710 to 17863,7 Rio de Janeiro1751 to 18174,8
Do.1786 to 18358,3 Do.1817 to 18324,3

In the 2d and 3d divisions the annual change is small; in the 1st and 4th considerably greater. It is greatest at the southern station in South America; the observations at Valparaiso, Concepçion, Tierra del Fuego, and the Falkland Islands, concur in shewing it to exceed 8′. The observations at Ascension, St. Helena, and the Cape of Good Hope, concur in shewing an annual change in that quarter of the 1st division exceeding 6′.

As the south dip decreases in South America, and increases in Africa, it is obvious that somewhere intermediately the dip must be stationary. Between Africa and New Zealand, for the same reason, there must be a second locality so characterised. Between New Zealand and Otaheite, a third; and between Otaheite and the west coast of South America, a fourth. Captain Fitz-Roy has

stations in the second of these localities only, between Africa and New Zealand. At Hobart Town, Sydney, and King George Sound, there appears to have been little or no change in the dip since the commencement of the present century.

The arrangement of the changes of dip in the southern hemisphere in four divisions, characterised by an alternate increase and decrease of dip, is in correspondence with the double flexure of the lines of dip; and is a consequence of the western motion of the two southern magnetic poles.