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J^ 



330 



ON ATMOSPHERIC WAVES 



[Sect. X. 



ascertain, l)y means of the three-hourly observations, the 

 increase of oscillation as they approach the Cape. The 

 same thing will hold good with regard to Cape Horn : it 

 appears from ])revious observation that a permanent 



barometric depression exists in this locality, most pro- 

 bulny in some way connected with the immense depression 

 noticed by Captain Sir James Clark Ross, towards the 



Antarctic Circle. The general character of the atmos- 

 phere off Cape Horn is also extremely different from its 

 character at St. Helena. It would therefore he well for 

 vessels sailing into the Pacific by Cape Horn, to continue 

 the three-hourly observations until the 90th meridian is 

 passed. 



Before quitting the Atlantic Ocuc... it may be well to 

 notice the marmc stations mentioned in my Third Report 

 on Atmospheric Waves,* as being particularly suitable for 

 testing the views advanced in that report and for tracing 

 a wave of the south-westerly s) stem from the most western 

 point of Africa to the extreme north of Europe. A series 

 of hourly observations off the western coast of Africa has 

 already been suggested. Vessels staying at Cape Verd 



Islands should not omit to make observations at three 



circumstances will 

 Canaries, Madeiras 

 should be made. 



'3 



alloWj hourly readings. At the 



and the Azores, similar observations 



Vessels touching at Cape Cantin, 



^ V. ^^. .iici,-^^7. vt;?<bei« loucnmg at i^ape uantm, 



Tangier, Gibraltar, Cadiz, Lisbon, Oporto, Corunna, and 

 Brest, should also make these observations while they are 

 in the localities of these ports. At the Scilly Isles we 



Keports of the British Association for the Adyaneement of Science, 

 184:0, p. 139. 



* 



f 



