244 Mr C Martins on the Nature and Origin of 



by the long track of fine weather, often experience a dis- 

 appointment which they would have avoided if they had 

 chosen a fine day preceded or followed by days of rain. 

 When the sun penetrates into this smoke, he assumes a red- 

 dish tint, his splendour is much weakened, and the disk 

 appears surrounded with concentric circles having a vibra- 

 tory motion. 



Hygrometrical instruments remain unaltered on the 

 appearance of this fog ; or, to speak more correctly, they 

 move to the point of dryness, as experiments by myself and 

 others prove. 



M. Willkomm is the only observer who reached this fog 

 and penetrated into it ; but he represents it as a vapour re- 

 sembling a mirage, which continually flees before the travel- 

 ler. Thus, when he arrived at the villages or mountains, 

 the view of which was concealed by the horizon-smoke, even 

 when he was in the midst of it, he was unconscious of its 

 presence. Nothing informed him that he was surrounded 

 with an air which, seen at a distance, appeared as opaque as 

 a thick smoke could have done. 



With circumstances so extraordinary before us, we do not 

 hazard any hypothesis ; and confine ourselves to making a 

 new appeal to the zeal of meteorologists, astronomers, and 

 travellers. 



The Callina or horizon- smoke in Spain.* 



The fog to which Spaniards give the name of Callina has 

 no connection with those which we name dry fogs (Land- 

 rauch). The latter are caused by the combustion of peat in 

 the north ; at least that has been demonstrated in the most 

 evident manner in regard to many of them. I shall not 

 enter on the question whether the dry fogs of Germany are 

 smoke arising from the combustion of heath or peat in East- 

 ern Friesland, the Duchy of Oldenburg, the provinces near 

 the Baltic, Russia, Scandinavia, or Iceland. The callina of 

 the south of Spain has not the same origin ; in fact the dry 

 fog of Germany is a local phenomenon, appearing suddenly, 

 continuing a few days and then disappearing. It has the 



* By Maurice Willkomm. 



