282 Report of the Voyage of Discovery 
two points of the magnetic equator, of which the co-ordinates 
are: 
Long. 83° 38! W. Lat. 7° 45! S. 
Long. 85° 46’ W. Lat. 6° 18! S. 
In the charts of MM. Hansteen and Morlet, the latitudes 
are about one degree Jess. Here the difference is in a con- 
trary direction to that which we found in the Atlantic Ocean: 
towards the coasts of Peru, the magnetic equator seems then 
to have become more distant from the terrestrial equator. 
Let us, lastly, proceed to the two points determined directly 
during the circumnavigation of the Coquille, in the northern 
part of the line of no dip. M. Duperrey has found for their 
co-ordinates :. 
Long. 170° 37’ 24" E. Lat. 0° 53! N. 
Long. 145° 2’ 38" EK. Lat. 7° O'N. 
These latitudes are Jess on the charts which represent the 
equator of 1780. In the part of the equinoctial ocean corre- 
sponding to the Carolines and to the Mulgrave Islands, the 
line of no dip seems now, notwithstanding, to remove from the 
terrestrial equator. 
Variations apparently so contradictory, will notwithstanding 
admit of a very simple explanation, even without its being ne- 
cessary to admit a change of form in the magnetic equator, 
provided we suppose that this curve is endowed with a trans- 
latory movement, which, from year to year, transports it pro- 
gressively and in mass from the east to the west. From 1780 
to the present period, this retrogradation of the nodes, in order 
that the numerical value of the change observed in the lati- 
tudes may be deduced from it, should hardly be below 10°. 
If the rapidity of this change of position be looked upon as an 
objection, we would remark that the direct observations of the 
position of the nodes lead very nearly to the same results. 
M. Duperrey has found, in fact, a node of the curve at about 
172° east longitude: on M. Hansteen’s map this node is placed 
at the 184th degree. In the South Sea, the tangent node of 
M. Morlet, and thetwo nodes of M. Hansteen are found between 
the 108th and the 126th degree of west longitude. Very ex- - 
act observations made on board the Uranie, in 1819, and which 
M. Freycinet has had the goodness to communicate to us, 
carry this node as far as the 132d degree of longitude. 
Indeed we find, in a work by Captain Sabine, published only 
a few weeks since by order of the British Board of Longitude, 
an observation which shows in a manner no less evident 
that the point of intersection of the two equators, which was 
situated in Africa, in the interior of the continent, and pretty 
far from the coast in 1780, has advanced from the east to the 
west 
