WI^DS FEOM THE MOUNTAINS. 201 



lished, an ebb and flow, a rising and falling atmospberic tide, regulated 

 in its intensity by tbe variations of tbe temperature ; and bere we 

 see again, as in tbe coast breezes, tbe rotatory movement pointed out 

 by Dove. 



As an example of tbese breezes, called in tbe Frencb Alps pontias, 

 rehats, aloups du vent, we may cite the tbree aerial currents which 

 flow incessantly in the valleys of Savoy, unless tbe local system of at- 

 mospheric currents be modified by tempests. These three streams of air 

 are those of Faucigny, Tarentaise, and Maurienne. The first traverses 

 the valley of tbe Arve from Geneva to Mont Blanc ; the second moves 

 in the valleys of the Isere, and its tributary, the Doron ; the third 

 alternately ascends and descends the valley of the Arc towards Mont 

 Cenis and the pass of Iseran. Ordinarily, the ascending wind com- 

 mences towards ten o'clock in the morning in the valleys of Savoy, 

 and the descending current flows back again towards the plains at 

 nine o'clock in the evening. In certain places, it is called fnatiniere, 

 because it makes itself felt, most of all, before the rising of the sun. 

 M. Fournet, who has for a long time studied these phenomena of 

 atmospheric tides, has ascertained that the passage, from the ebb to the 

 flow, is especially rapid in the narrow defiles, while in the large 

 basins the alternation is produced after a series of aerial oscillations, 

 and gusts of wind in the opposite direction. Each valley owes a spe- 

 cial atmospheric condition to its particular form ; in one, the successive 

 breezes are slow and undecided in their pace ; in another, they alter- 

 nate abruptly, and with violence, producing in the space of a few 

 hours variations of temperature of 35, 45, and even 6b degrees. 

 In general, the breezes are regular in the regular valleys, and only 

 present remarkable peculiarities at their issuing into the plain, or else 

 at the confluence of two gorges. Among these winds with peculiar 

 motions, a breeze of the E-benish basin may be mentioned, known 

 under the name of the Wisper-wind. Emerging above Lorch, from the 

 narrow valley of the Wisper, which is filled with woods, and so situ- 

 ated as to be subject in its difierent parts to all the extremes of temper- 

 ature, this breeze generally blows till eight, nine, or ten o'clock in the 

 morning, then crosses the Rhine, strikes against the rocks of the left 

 bank, and divides into two currents, one of which re-ascends to the south 

 towards Bingen, increasing itself on the way by several small tributary 

 winds ; while the other, which is weaker, descends to the north 

 towards Bacharach. 



Even in tbe plains and countries but slightly varied in surface, 

 daily breezes may succeed each other regularly, because of local differ- 



