296 CLIMA TIC CHANGES IN THE PRAIRIE REGION. 



those having the best opportunities of deciding correctly, that extensive areas have 

 been replanted, with favorable effects, it is said, anticipated by the projectors of 

 the enterprise." 



The Imperial Academy of Vienna in 1073, appointed a special committee 

 composed of distinguished savans, members of the constitution, to discuss and 

 report upon a memoir presented previously by Mr. Hofruther Wex ' ' upon the 

 diminution of the water of rivers and streams." These sessions were held by the 

 committee and the memoir of Mr. Wex exhaustively argued. An immense mass 

 of statistics were presented and the report of the commission, elaborate in details, 

 sums up its opinions as follows, for which only we have room: "The fact of the 

 diminution of water in streams, which diminution is connected with the copious- 

 ness of springs which supply them, being admitted, the commission find the cau- 

 ses of this phenomenon: 1st. In the continued cutting down of the woods whose 

 salutary influence in the raising of the hygrometer, the amelioration of external 

 temperature, the decrease of evaporation, and the promotion of a regular escape 

 of the precipitation is evident. 2d. In the desiccation of the lakes, ponds and 

 bogs, which likewise raises the hygrometic conditions, decreases evaporation, 

 moderates extreme temperatures, and lastly, through the fissures in the soil, directly 

 promotes the formation of springs." * * * 



It has been abundantly shown in the foregoing references, that the desica- 

 tion of lakes and bogs, which the Vienna Academy, in the report of its commis- 

 sion, assigns for the second cause for the " diminution of water in rivers and 

 springs," is directly attributable to the extinguishment of the forest; consequently 

 the causes which the commission finds, to account for the phenomena under their 

 consideration, may be stated fully in their first conclusion. In other words, the 

 conditions for which they were to assign a cause, is found in the disboscation of 

 the timber of the affected region. 



The devastating and disastrous climatic results of disrobing a country of its 

 wealth of timber, have been so incontestibly proved by the distinguished authori- 

 ties quoted, that it leaves very little room to doubt the correctness of the conclu- 

 sions arrived at, and they are consequently divested of any hypothetical aspect. 



In order fully to comprehend the relations of forests to climate, it is neces- 

 sary to devote a little space to the nature of vegetation, and the process by which 

 vegetable life is sustained. 



Nearly all the inorganic matter essential to the perfect development of plant 

 life is extracted by the secret operations of nature from the soil surrounding their 

 root 4 ;, while the sugar, acids and starch are derived from the air. 



The rainfall is the agent by which inorganic substances are so disposed that 

 the roots are enabled to select and assimilate that portion which is essential to the 

 life of the plant. 



Carbonic acid, a substance as necessary to the support of vegetation as 

 atmospheric air to animal life, is constantly absorbed by day, by the leaves of 

 plants, the carbon of which is separated by them and metamorphosed into 

 woody fibre ; the oxygen, the other element of the compound, being rejected, is 



