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PLATE CLVIIL "SMOKE" OF MOUNT EREBUS AS A 



WIND-VANE. 



From a pencil sketch, showing the summit of Mount Erebus from M'Murdo 

 Sound. 



In this sketch the " smoke " of Mount Erebus is seen to be giving very exact 

 information as to the level at which a calm changes into a breeze. The height of the 

 lower limit of the moving air can easily be estimated by the height of the summit 

 itself, in this case it is about 14,000 feet above sea-level. 





