276 BBLATION OP FORESTS TO THE 



LoealHy. 



Pierreohatel, 



Varambon 



Saint Bambert 



Syam, ... 



Saiat-CIaude, 



Fontarlier, 



Fort-de-Jonx, 



Saint-Cerques, 



" At the convent of the great Saint Bernard (altitude, 2620 

 mfetres, = 8733 feet) there is collected annually 1500 millimetres (60 

 inches) of water. If the most elevated pluviomfetre in Europe be at 

 the same time one of those giving the high measurements, the cause 

 of this is perhaps less its altitude than its topographical position. 

 The instrument is placed in a narrow embrasure, dominated by 

 glaciers, in which the winds, come from what direction they may, 

 must pass on violently, and be rapidly cooled. 



" The obstacle once passed, the rain diminishes — ^the current 

 descends and becomes heated again ; desirous of repairing its loss, 

 it drinks up the clouds with avidity, and dries up the mountain 

 slope on the opposite side." 



Giving then a graphic account of the appearance presented by a 

 sea of clouds rising up a mountain side and pouring over into the 

 valley beyond, when this is contemplated from a surmounting height, 

 which has been already quoted (ante p. 157), he goes on to say, — 

 " That the superficial aspect of a country has an important influence 

 on the phenomena of the rain may be illustrated by many well- 

 known cases. 



" On the two sides of the Scandinavian Alps, the west wind and 

 the east wind give inversely fine weather and rain, the one to Sweden 

 and the other to Norway. 



" When it rains at Narbonne the sun shines at Montauban. 



" The rain comes from the west in Switzerland, and from the east 

 in Lombardy. It is in consequence of its being sheltered from the 

 south and , southeast winds, which drench the basin of the Rhone 

 that the valley of the Durance presents that exceptionally dry climate 

 which M. Surell points out to be favourable to the development of 

 torrents.* It rains upon an average, at Marseilles, 57 days in the 

 year; at Aries, 45 days; at Aix, 40; but in the region of the Durance 

 it rains only 38 days in the year.t 



• Surrel, chap. xxi. f Arago : Melanges, p. 430. 



