CLIMATIC CHANGES IN THE PRAIRIE REGION. 311 



turn, flowing over the latter when it is in an inclined position, and eventually ris- 

 ing in streams or fountains; the water of wells has the same origin. Large 

 springs are ordinarily found in mountainous regions. Forests also contribute to 

 the formation of springs, not only by reason of the humidity which they produce 

 and the obstacles which they oppose to the evaporation of the water which falls 

 on the surface, but further because the roots of the trees, which, by dividing the 

 soil render it more pervious, and thus facilitate infiltration." 



Strabo informs us that it was necessary to take great precaution to prevent 

 the country of Babylonia from being submerged. The Euphrates, which begins 

 to swell, he tells us, at the close of spring, when the snow melts on the moun- 

 tains of Armenia, overflows at the beginning of summer, and would necessarily 

 form vast accumulations of water on the cultivated lands were not the superflux 

 turned aside by means of trenches ; this state of things exists no longer. M. 

 Oppert, who, some years ago, traveled all through Babylonia, reports that the 

 volume of water conveyed by the Euphrates is much less than in past ages, that 

 inundations no longer occur, that the canals are dry, the marshes exhausted by 

 the great heats of summer, and that the country has ceased to be insalubrious. 

 This retreat of the water can only be attributed, as he found means to satisfy 

 himself, to the clearing away of the forests on the mountains of Armenia. 



DeSaussuref long ago pointed out the diminution of the water of the lakes 

 of Switzerland— especially in lakes Morat, Neufchatel and Bienne, as a conse- 

 quence of the clearing away of the forests. 



Choiseul Gouffier was not able to distinguish in the Troad the river Scaman- 

 der, which was still navigable in the time of Pliny. Its bed is now entirely dry ; 

 but the cedars also, which covered Mount Ida, whence it took its source, as well 

 as the Simois, exist no longer * * * 



M. Boussingault cites several examples leading to the same conclusions, but 

 I will offer only two : "In 1826 the metalliferous mountains of Marmato pre- 

 sented only some miserable cabins inhabited by negro slaves. In 1830 this state 

 of things no longer existed ; there were numerous workshops and a population of 

 three thousand inhabitants. It had been found necessary to level much wood ; 

 this denudation had proceeded but two years, and already a diminution was per- 

 ceptible in the volume of water available for the labor of the machines." The 

 other example cited by the same distinguished authority was furnished from the 

 high table-lands of New Granada, elevated from six thousand to ten thousand 

 feet above the sea level: "The inhabitants of the village of Dubate, situated 

 near two lakes, which were united sixty years ago, have witnessed the gradual 

 subsidence of the waters, insomuch that lands which, thirty years ago, were 

 under water are now subject to culture." M. Boussingault satisfied himself by a 

 most rigid investigation that the diminution of the water in the lakes was caused 

 by the extensive removal of forests in that vicinity. He found at the same time 

 that Lake Tota, not far from Fuquene in that country, in a locality where the 

 woods had not been disturbed, had suffered no loss in the volume of its water. 



M. Desbassyres de Richemont states* that in the Island of Ascension a mag- 



fVoyage dans les Alpes. "Cours d' Agriculture de M. deGasparin. 



