Report on Terrestrial Magnetism. 827 



netical observations should be made. It is generally considered 

 that the variation there has, for a very long period, undergone 

 but little change ; and, on this account alone, it would be very 

 desirable to ascertain, with precision, the amount of the varia- 

 tion, so that hereafter the nature of the changes it may undergo 

 may be accurately determined. Its position also, with reference 

 to the magnetic equator, is one which would recommend it as a 

 magnetical station.* 



Although M. de Humboldt has not adverted to any other 

 point besides Ceylon in our Indian possessions, yet no doubt he 

 would, with us, consider it desirable that observatories should 

 be established at different points on the continent of India ; and 

 it appears to us that Calcutta and Agra are in positions well 

 adapted for the purpose. As, however, there is an Astronomi* 

 cal Observatory established at Madras, there would be greater 

 facility in obtaining magnetical observations there than at places 

 where no such establishment exists. We feel assured that the 

 East India Company, which has shewn so much zeal and libe- 

 rality in the promotion of scientific inquiry, and such a desire 

 for the advancement of scientific knowledge in the extensive 

 possessions under its controul, would afford its powerful assist* 

 ance in the establishment of observatories for the investigation 

 and determination of the laws of phenomena intimately connect^ 

 ed with navigation, and, consequently, with the commercial 

 prosperity of our country. 



We consider, also, that Gibraltar and some one of the Ionian 

 Islands are very desirable stations for the establishment of per* 

 manent magnetical observatories ; and, to come nearer home, 

 that such observatories should be established in the north of 

 Scotland and in the west of Ireland, 



* Mr Pentland, who has been appointed Consul-General to the Republic 

 of Bolivia, having, since the Baron de Humboldt's letter was referred to us, 

 offered his earnest co-operation in the objects contemplated in that letter, we 

 cannot hesitate, now that this has been communicated to us, to recommend 

 that an offer so liberal should be made available to science. If accurate mag- 

 netical observations were made at some station on the elevated table-land of 

 Mexico, and simultaneously at another not very distant station, nearly at the 

 level of the sea, we consider that they would determine points relative to the 

 influence of elevation on the diurnal variation, the dip and intensity, respect- 

 ing which our information is at present, to say the least, extremely deficient- 



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