Narrative of a Survey of the Intertropical and Western Coasts of Australia Volume II Part 29

July : Endeavour River, East Coast : 15 27 : 145 11 : 38 00 00 : South : 5 27 East : Taken at the tent.

1818. April : Goulburn Island, North Coast : 11 38 : 133 20 : 27 32 30 : South : 2 0 East : Taken on Bottle Rock, in South-west Bay.

1820. October : Careening Bay, North-west Coast : 15 6 1/4 : 125 0 : 38 44 36 : South : 0 43 1/2 West : Taken at the tent.

Dip of the Needle at Port Louis, Simon's Bay, and various parts of the Atlantic Ocean, observed upon the Bathurst's return to England.

1821. November : Port Louis, Mauritius : 20 10 : 57 29 East : 51 42 : South : 12 00 West : On sh.o.r.e.

1823. February : Simon's Bay, Cape of Good Hope : 34 11 2/3 : 18 28 1/2 : 48 23 1/2 : - : 28 to 30 : On sh.o.r.e.

February 9 : False Bay 5 minutes East-South-East of Simon's Bay : - : - : 48 48 : - : 28 to 30 : On the binnacle.

February 14 : At Sea : 27 18 : 8 50 : 37 57 1/2 : - : 24 00 : On the binnacle.

February 16 : At Sea : 23 47 : 4 2 : 30 10 : - : 24 00 : This observation is correct to 3/4 degree.

The situation for the above observation bears East 5 degrees North from the place where the same dip was observed by M. Perouse on the Coast of Brazil.

February 20 : At Sea : 17 7 : 4 57 West : 15 42 1/2 : - : 21 9 : Correct to 1/2 degree.

The above situation bears East 16 1/2 degrees North from the place where Commodore Baudin observed the dip of 15 degrees; and East 14 degrees North from the observation of 14 degrees by M. Perouse.

February 24 : At Sea, four leagues North-North-West from St. Helena : - : - : 11 45 : - : 20 35 : Correct to 1/2 degree.

February 26 : At Sea : 14 25 : 7 53 : 7 56 1/4 : - : 18 54 : Correct to 1/2 degree.

1823. February 27 : At Sea : 12 42 South : 9 21 West : 3 6 3/4 : South : 18 28 West : -.

Upon placing the instrument with the end marked 180 degrees in the direction of North 45 degrees East the needle dipped 4 30.

Upon placing the instrument with the end marked 180 degrees in the direction of North 67 East the needle dipped 11 30.

Upon placing the instrument with the end marked 180 degrees in the direction of North 78 East the needle dipped 14 30.

Upon placing the instrument with the end marked 180 degrees in the direction of North 85 East the needle dipped 18 15.

Upon placing the instrument with the end marked 180 degrees in the direction of North 88 East the needle dipped 20 0.

Upon placing the instrument with the end marked 180 degrees in the direction of North 91 East the needle dipped 25 0.

Upon placing the instrument with the end marked 180 degrees in the direction of North 92 1/2 East it was vertical.

Upon placing the instrument with the end marked 180 degrees in the direction of North 95 East the needle s.h.i.+fted on the opposite side to 65 0.

Upon placing the instrument with the end marked 180 degrees in the direction of South 45 East the needle s.h.i.+fted on the opposite side to 3 40.

Upon placing the instrument with the end marked 180 degrees in the direction of South 45 West the needle s.h.i.+fted on the opposite side to 3 0.

Upon placing the instrument with the end marked 180 degrees in the direction North 45 West the needle s.h.i.+fted on the opposite side to 5 30.

The mean of the observation, on placing either end North and South was 3 6 3/4 degrees.

The mean of the observation, on placing either end North-East and South-West was 3 45.

The mean of the observation, on placing either end South-East and North-West was 4 35.

1823. February 28 : At Sea : 11 44 South : 10 12 West : 1 25 : South : 17 to 18 West : -.

Upon placing the instrument in the direction of North 45 East the needle dipped 2 10.

Upon placing the instrument in the direction of North 60 East the needle dipped 2 50.

Upon placing the instrument in the direction of North 70 East the needle dipped 4 25.

Upon placing the instrument in the direction of North 80 East the needle dipped 5 15.

Upon placing the instrument in the direction of North 90 East the needle dipped 8 15.

Upon placing the instrument in the direction of North 92 East the needle dipped 14 00.

Upon placing the instrument in the direction of South 60 East the needle s.h.i.+fted.

Upon placing the instrument in the direction of South 45 East the needle s.h.i.+fted 2 20.

Upon placing the instrument in the direction of South 45 West the needle s.h.i.+fted 1 40.

Upon placing the instrument in the direction of North 45 West the needle s.h.i.+fted 1 00.

Mean when placed at North-East and North-East 1 55.

Mean when placed at North-West and South-East 1 40.

February 28 : At Sea : 11 30 1/2 : 10 20 : 0 45 : South : 17 to 18 West : -.

February 28 : At Sea : 11 5 1/2 : 10 34 : 0 15 : North : 17 to 18 West : -.

From the above observations, it would appear that the Magnetic Equator crosses the meridian of 10 1/2 degrees West, in 11 degrees 12 minutes South lat.i.tude. At the latter observation--when the direction of the instrument was changing, the needle remained quite stationary, the south end of the needle pointing to the north, until the change was effected; it remained in this position for two seconds of time, and then suddenly s.h.i.+fted to the opposite, its proper, direction; its movements were, however, very sluggish and irregular in its s.h.i.+fting end for end. The day was so rainy that no observation could be made for the variation of the compa.s.s.

March 1 : At Sea : 10 1 South : 11 31 West : 3 32 1/2 : North : 17 44 West : -.

March 2 : At Sea : 8 21 South : 12 57 : 6 50 : North : 18 00 : -.

March 5 : At Sea : 7 3 South : 15 42 : 11 22 1/2 : North : 16 5 : -.

March 7 : At Sea : 4 17 South : 18 50 : 19 15 : North : 13 18 : -.

March 9 : At Sea : 0 0 1/3 South : 22 6 1/4 : 27 45 : North : 12 51 : -.