EDDIES OF TEMPESTS. 



295 



of summer originate to the right or left of the Gulf-stream, and 

 are developed in gyrations, caused by the movement of the earth 

 itself.* There are likewise local cyclones, revolving only over a 

 single country like France or England or even in a single valley ; we 

 might cite numerous examples of similar tempests which in a limited 

 space have been scarcely less destructive than the hurricanes of the 

 Antilles. t Often when we contemplate the sky above our heads, we 



K 



Fig. 119.— Storm in the Pyrenees ; after Lartigue. 



see clouds whirling under the influence of two hostile currents and 

 approaching one another only to withdraw again. But it is princi- 

 pally by ascending the side of a mountain that one can witness the 

 curious sight presented by the conflict of two masses of air, which 

 dive into a valley and describe a more or less rapid eddy with their 

 clouds or mists. From the top of the headlands of the Pyrenees the 

 meteorologist Lartigue has observed a great number of these circular' 

 * Sonrel, Nouvelles Meteorologiques, March, 1868. f Fitzroy, Weather-iooJc. 



