426 



Although M.de Humboldt has not adverted to any other point be- 

 sides 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 Astronomical Observatory established at 

 Madras, there would be greater facility in obtaining magnetical ob- 

 servations there than at places where no such establishment exists. 

 We feel assured that the East India Company, which has shown so 

 much zeal and liberality in the promotion of scientific inquiry, and 

 such a desire for the advancement of scientific knowledge in the ex- 

 tensive possessions under its controul, would afford its powerful as- 

 sistance in the establishment of observatories for the investigation 

 and determination of the laws of phenomena intimately connected 

 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 permanent 

 magnetical observatories 3 and, to come nearer home, that such ob- 

 servatories should be established in the North of Scotland and in the 

 West of Ireland. 



M. de Humboldt adverts to another very interesting class of mag- 

 netical observations, those in the mines of Freyberg. The mines 

 of Cornwall from their great depth, some being 1200 feet below the 

 level of the sea, are peculiarly well adapted for observations of this 

 description ; and, from the spirit with which philosophical inquiry 

 has been carried on in that part of England, we do not anticipate 

 that much difficulty would occur in the establishment of a magne- 

 tical station in one of these mines. 



Having enumerated the stations which by their position appear 

 best adapted to furnish valuable results, and having likewise pointed 

 out the facilities which some afford for the execution of this plan of 

 observation, immediately that the nature of the instruments to be 

 employed has been determined upon, and that such instruments 

 can be provided, it may be proper to advert to stations where, al- 

 though the same facilities do not exist, we consider that zealous and 

 able observers might be obtained without much difficulty. We con- 

 ceive that such is the case in Newfoundland, in Canada, at Halifax, 

 Gibraltar, in the Ionian Islands, at St. Helena, and Ceylon ; and we 

 have authority for stating that there would be no difficulty in ob- 

 taining observers in the Mauritius, and even at the colony on the 



offered his earnest cooperation 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, 

 respecting which our information is at present, to say the least, extremely 

 deficient. 



