different kinds of Dry Fogs. 245 



smell of burning, or at least a peculiar smell, and envelopes 

 the objects near it in a bluish vapour. The callina is com- 

 pletely different ; it is a permanent fog which every year, 

 during the whole summer, covers the horizon and impairs 

 the transparency of the sky. I have observed it for two 

 years, always in the same circumstances. 



The callina appears in the middle or at the end of June. 

 It forms around the horizon a band of fog of a bluish -gray 

 colour, which increases with the temperature. In the 

 middle of August, when the temperature reaches its maxi- 

 mum, it covers about a quarter of the celestial vault. At 

 this time the colour of the fog at the horizon is of a reddish 

 brown. Higher up it passes into yellow, and from its edges 

 rises a transparent vapour like a light gauze, which covers 

 the whole sky and imparts to it a leaden hue. When the 

 callina reaches this degree of intensity, it embraces the 

 whole horizon, and disturbs the view of objects to a distance 

 of three or four leagues. All those objects which are nearer 

 are, on the contrary, perfectly distinct. I have never felt 

 the least odour, and we do not observe when we enter into 

 the fog. The nearer we approach to an object veiled by the 

 callina, the more distinct its outlines become, and at the dis- 

 tance of some leagues it is perfectly distinct and in full 

 light ; no trace of the fog is seen around one. 



From the end of August the callina diminishes with the 

 heat, and disappears in the end of September or in the be- 

 ginning of October, at the time when the equinoctial gales 

 prevail. Sometimes it diminishes when the approach of a 

 storm refreshes the atmosphere, which is in general very 

 rare in summer. But on the following day after the storm, 

 the thickness of the callina is much less, the sky purer and 

 of a deeper blue. At the end of a few days it recovers its 

 former dimensions. I have observed the callina in the warm 

 plains of the Guadalquiver, of La Mancha, in the Asturias, and 

 the province of Almeria, more rarely among the mountains. 

 Its increase and diminution with the temperature seems to 

 indicate a connection with it. This is likewise the opinion of 

 the people of Spain. 



