1849.] 



exercised hy Trees on Climate . 



413 



yet impossible to explain the mode in which trees and forests thus 

 exercise their influence. From the writings of the authors above 

 quoted it would seem as if several agencies were at work, and that 

 independent of the supposed electric action which the mountain 

 forests give rise to and of the attracting and condensing apparatus 

 which their leaves are likened to, they produce a spongy tenacious 

 under-soil which they protect from the di^ying eflect of the winds 

 and sun's rays, and by this means cause the rain that falls to 

 trickle slowly to the lower lands and keep up a constant supply of 

 water in the streams ; and it will have been evident also that the 

 trees which clothe the mountain summits are regarded by other 

 authors, as a vast condensing apparatus placed by nature on tlie 

 elevated parts of the earth to distil the waters of the clouds which 

 so constantly enshroud their heights. While we are as yet only 

 learning the laws that regulate the development of electricity, and 

 its action on the surrounding atmosphere we know how great an 

 influence it exercises on vegetation, and it is not impossible that 

 mountain forests will ultimately be proved to be great electric 

 forces placed by nature for the purpose of promoting the fall of 

 rain. The most agreeable of the writers on this subject is St. 

 Pierre who traces in every forest, tree, and shrub, and in every 

 leaf and branch evidence of wise and beneficent design, which he 

 beautifully alludes to when describing " the elementary harmonies 

 of plants with the water and the air by means of their leaves and 

 of their fruits."* 



l\nien the author of nature resolved to crown with vegetables 

 even the highest pinnacles of the earth, he first adapted the chains 

 of the mountains to the basins of the seas, which were to supply 

 them with vapors ; to the courses of the winds which were to 

 waft them thither, and to the different aspects of the sun from 

 which they were to receive warmth. As soon as these harmonies 

 were established between the elements, the clouds ascended from 

 the ocean and dispersed over the most remote parts of the conti- 

 nents. They there diff'used themselves in a thousand different 

 forms, in fogs, in dews, in rains, in snows, in frosts. They distil- 

 led from the upper regions of the atmosphere in manners equally 

 various ; some in a calm air, like our spring showers, fell in perpen- 



* St. Pien-P; Studies of Natiu-c. Londou, 1646, rcl. li, p- 23. 



