1840.] 



exercised I y Trees on Climate. 



417 



Tlie bark of most mountain-trees is in like manner adapted 

 to convey tlie rain water from the branches to the roots. That 

 of the pine is in large perpendicular ridges ; that of the elm is 

 split and cleft longitudinally ; that of the cypress is spungy like 

 tow. 



The plants of mountains and of dry situations have farther a 

 ciiaracter which is peculiar to them, in general, it is that of attract- 

 ing the water which floats in the air in imperceptible vapors. 

 The parietaria, or pellitory, which has derived its name " a fa- 

 riete'' because it grows on the sides of walls, has its leaves al- 

 most always humid. This attraction is common to most of the 

 mountain- trees. All travellers agree in asserting that hi the 

 mountains of Eerro, one of the Canary Islands, there is a tree 

 which every day furnishes that island with a prodigious quantity 

 of water. The natives call it garoe and the Spaniards santo on 

 account of its utility. They tell us that it is always surrounded 

 with a cloud which distils abundantly down its leaves, and re- 

 plenishes with water capacious reservoirs which are constructed 

 at the foot of the tree, and afford a copious supply to the island. 

 This effect is probably somewhat exaggerated, though reported 

 by persons of different nations, but I give credit to the general 

 fact. The real state of the case I take to be this, that the moun- 

 tain attracts from afar the vapors of the atmosphere and the 

 tree being situated in the focus of that attraction collects them 

 around it. . 



Having frequently spoken in the course of this work of the 

 attraction of the summits of different mountains the reader will 

 not be displeased if I here present him with an idea of this 

 portion of the hydraulic architecture of nature. Among a great 

 number of curious examples which I could adduce and which 

 I have collected among my materials on the subject of geography, 

 I shall quote one extracted not from a systematic philosopher but 

 from a simple and sprightly traveller of the last century, who 

 relates things as he saw them, and without deducting from them 

 any consequences whatever. It is a description of the peaks of 

 the Isle of Bourbon situated in the Indian Ocean in the 21st de- 

 - gree of south latitude. It was drawn up from the papers of 

 M. de Vniers, who was then Governor of tlie island under the East 



