425 



that the most advantageous positions would be, one near the most 

 northerly establishments in Hudson's Bay, and another at or near to 

 Fort Resolution on Great Slave Lake. As, however, observers in 

 such positions would be placed almost beyond the pale of civilization, 

 we fear that, for some time at least, it will be found quite impracti- 

 cable to obtain regular observations at these important stations. It 

 would likewise be desirable that there should be a station in Nova 

 Scotia or Newfoundland: the latter would be the preferable position. 



If the Government of the United States were to give their cordial 

 cooperation to M. de Humboldt's plan, by the establishment of three 

 or more permanent magnetical observatories, in different longitudes, 

 these, with what we may expect to be undertaken by Russia in the 

 extreme north-west, and our own establishments, would afford the 

 means of obtaining a mass of more interesting magnetical observa- 

 tions than could perhaps be derived from any other portion of the 

 earth's surface. 



M. de Humboldt mentions New Holland, Ceylon, the Mauritius, 

 the Cape of Good Hope, St. Helena, and a point on the east coast of 

 South America, as desirable stations, and we fully concur in the 

 propriety of the selection. Although Van Diemen's Land, from 

 its greater proximity to the southern magnetic pole, would be a 

 more advantageous position for magnetical observations than Para- 

 matta, yet the circumstance alone of there being an astronomical 

 observatory established at Paramatta, renders it peculiarly adapted 

 for a magnetical station. Possibly circumstances may hereafter 

 admit of magnetical observations being aiso made at Hobart Town, 

 in conformity with the general plan which may be adopted. 



The Island of Ascension, from its proximity to the magnetic 

 equator, would possess peculiar advantages for a magnetical station ; 

 but these must, in a great degree, be counterbalanced by the nature 

 of its soil, which, being wholly volcanic, would exert an influence 

 on the needle that would render observations made there of a doubt- 

 ful character: indeed, the same objection applies to St. Helena and 

 most of the islands of the Atlantic. Some recent observations, those 

 of Lieut. Allen, R.N., in the expedition up the Niger, would point 

 to the Bight of Benin as a desirable station; but the insalubrit}' of 

 the climate and other circumstances prevent our recommending 

 its adoption. 



•M. de Humboldt has not referred to any station in our West In- 

 dian colonies, but we consider that circumstances point to Jamaica 

 as a station where it is very desirable that accurate magnetical ob- 

 servations should be made. It is generally considered that the va- 

 riation 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 variation, so that hereafter the na- 

 ture 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 *. 



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

 of Bolivia, having, since the Baron de Huniboldt"s letter was referred to us, 



