10 On M. Hansteen's recent Magnetic 



observations of M. de Rossel indicate in like manner that at 

 the period of his voyage, towards the close of the last century, 

 the several intensities, from that represented by 370", to that 

 represented by 278", were all comprised between Java in the 

 north-west, and Van Diemen's Land in the south-east. Hence, 

 as far as the evidence hitherto extends, it would appear that 

 there are two points of maximum intensity in the southern as 

 well as in the northern hemisphere : but the geographical posi- 

 tion of those points, and their respective intensities, relatively 

 to each other, and to the points of maximum in the northern 

 hemisphere, remain to be determined, and must be acknow- 

 ledged to be subjects of highly curious and important enquiry. 

 In the arrangement of magnetism, as exhibited to us on the 

 great scale of our globe, — differing, as it is now known to do, 

 so widely from the analogies with which it had been associated, 

 and indeed, I believe, from all analogy whatsoever with which 

 we are acquainted, — we cannot too soon inform ourselves accu- 

 rately of the facts. 



In selecting the parts of the southern hemisphere in which 

 enquiries of this nature may be most advantageously pursued, 

 regard must be paid, in the first instance, to the distribution of 

 land, on account of the convenience which its coasts and islands 

 afford in determining and connecting the isodynamic curves. 

 The eastern and western coasts of New Holland, and the ad- 

 joining island of New Zealand, — the western coast of South 

 America from Lima to Cape Horn, and a continuation to the 

 lands to the southward of Cape Horn approaching the Ant- 

 arctic Circle, — the islands which might be successively visited 

 in a course from the Cape of Good Hope to Desolation Island, 

 and from thence to the Mauritius, — present in this view the 

 directions of principal interest. Careful observations systema- 

 tically made in them, combined with the observations already 

 made, would advance our knowledge of the magnetic pheno- 

 mena of the southern hemisphere to the same stage that it has 

 attained in regard to those of the northern : viz. it would 

 establish the number of the governing points of intensity in the 

 hemisphere ; determine their respective geographical positions, 

 and, in great measure at least, their relative intensities; ascertain 

 the general arrangement of the curves ; and, finally, point out 



