116 ’Remarks on Professor Hansteen”*^ 
Magnetical Atlas % it will be seen, that his line of no variatiOHj^ 
(the dotted line in that figure), commencing to the west of Hud- 
son’s Bay, proceeds in a south-east direction, through the lakes 
of North America, past the Antilles and Cape St Roque, till it 
reaches the Southern Ocean ; that again it appears below New 
Holland, crosses that island, extends with a double sinuosity 
■through the Indian Archipelago, and, after stretching along the 
east coast of China, and up to the latitude of 71°, forms a semi- 
circular bend, and passes northward through the mouth of the 
White Sea. In all those windings, a system of vmnation-lines 
accompanies it on both sides, with more or less regularity, ac- 
cording to the distance ; but the peculiarity which principally 
engages the author’s attention, and of which he is at most pains 
to demonstrate the reality, is the position of those lines near their 
several extremities. By a multitude of observations, the evi- 
dence of which it is difficult to resist, Mr Hansteen thinks it 
proved that there are Jour points of convergence among the lines 
of variation on the globe, a weaker and a stronger in the neigh- 
bourhood of each pole. Comparing the observations made at 
one time with those made at another, it farther appears, that 
those points have a constant motion, which, admitting the hy- 
pothesis of its uniformity, may easily be calculated on the prin- 
ciple that leads to its discovery* At present, it would seem, 
the stronger point (A) of the southern hemisphere, is situated 
not far to the S.W. of Van Dieman’s Land, at the distance of 
^1° 8' from the pole, and of 132° 35' E. from the meridian of 
Greenwich ; the weaker point {pi) of the same hemisphere, is si- 
tuated to the S.W* of Terra del Fuego, at the distance of 11° 
44' from the pole, and of 135° 59' W. from Greenwich : the 
stronger point (B) of the northern hemisphere, again, is found 
above the American continent, distant 20° 22' from the pole, 
89° 24' W* from Greenwich ; and the weaker point (5) of the 
same hemisphere, in the Arctic Ocean, 4° 48' from the pole, 
140° 6' E. from Greenwich. Each stronger point thus lies op- 
posite, though very seldom diametrically opposite to the other ; 
the weaker points in like rnanner. The motion of both nor- 
thern points is from west to east obliquely ; of both southern 
* This Chart, forming Plate IV will be given in next Number. 
