6 PORTO PRAYA. [1843. 



considerable. The Consul, or principal merchant, should 

 be apprized of the exact spot, and the place should 

 be marked, if time permit, by some such effectual 

 method as digging a hole and filling it with lime and 

 stones, which will soon become a solid conglomerate. 

 Three good angles to conspicuous objects would also 

 assist in finding such a position. 



The amount of Magnetic Variation, or Dip, is well 

 known to vary on the eastern and western sides of 

 islands, and therefore on basaltic or trap formations 

 too much caution cannot be taken to select the same 

 localities used by former observers ; the data offered to 

 prove the question of annual change, can be of little value 

 otherwise, although we may notice in recent publications, 

 the deduction of this element from the year 1600 to the 

 present without any certain knowledge of the positions at 

 which they were observed. The result of our observations 

 at this position will be found in the Stations noticed in 

 the Appendix. 



On the 7th of March we quitted Porto Praya, but had 

 scarcely cleared the bay when a ship -of- war was descried 

 in the offing, On closing, we exchanged Numbers with 

 H.M.S. 'Madagascar', Captain Foote, senior officer on 

 the coast of Africa. Having letters and parcels for her, 

 it was fortunate we met ; but for this circumstance they 

 would have been delayed some months, being directed to 

 be forwarded from the Cape of Good Hope ! 



Our onward course to the Cape was as monotonous as 

 such voyages usually are ; we did not, however, pursue 

 " the beaten track ", but endeavoured, by adopting an 

 easterly route, to obtain a series of magnetic observations. 



