﻿114. 



Cincinnati Society of Natural History. 



the melting or freezing of Alpine snows above the tree-line, where there 

 are no trees to influence it, but where warm air can and does. 



The annual inundations of the Nile, also, are due to the direct rainfall 

 during the wet season in that immense central lake basin of Africa described 

 by Livingston and Stanley. The dense tropical forests and impenetrable 

 jungles there do not seem to stop the rise of precipitated waters, or aid the 

 forestry planters in their theory that the forest acts like a sponge and foli- 

 age prevents the access of the sun's rays to evaporate. The impassable 

 jungles of India, and the vast forests and foliage of that tropical climate? 

 do not prevent the great rises in the Ganges, when the wet season pours 

 down its rain. The same is true of the Amazon; so that turn where you 

 will, you are confronted by the facts that the floods come from precipitated 

 moisture — from rain or accumulated snow; that their extent depends upon 

 the amount of moisture precipitated, coupled with the warm air to aid to 

 melt that which is congealed, and not upon the forests or penetration of 

 the sun's rays. What sun's rays did we have in our recent fourteen days 

 of gloominess to aid in melting the snow faster? Yet it melted, and 

 rapidly, too. What protection are foliage or trees to permeating warm air, 

 like what we so often have in our warm waves? So far as the sponge- 

 theory part is concerned, it amounts to this: the soil is the great sponge 

 and vat; when its pores are frozen up, as it recently was here, and water 

 is dropped on, it runs off like water from a duck's back ; then one of the 

 elements for a flood or, rather, rapid freshet is present. I do not believe 

 that forests and foliage act as a sponge, except so far that they resemble 

 one soaked, upon which if you pour water, it already being full, an equal 

 amount of water escapes. The obstruction and friction which trees are to 

 water running down hill is something ; therefore, on the whole, the effect 

 of forestry is slight, but has, I think, been greatly overestimated. 



There is indisputable evidence that a large part of the Ohio Valley was 

 once a prairie like Illinois, and that herds of buffalo roamed over it. There 

 is also evidence that a larger population than the Indians, viz.: the Mound 

 Builders, once occupied and probably cleared a portion of it. Parts of it 

 which are now thickets were known as prairie-land to the early pioneers; 

 yet under all these variations, we have no evidence that it was barren re- 

 cently, or that the rises in the river were once more frequent or extensive 

 than at present; all of which should have been the case if the theory of 

 forestry is as true for the Ohio Valley as for Asia Minor. No ! either the 

 theory is wrong, and the present barrenness of Asia Minor is due to other 

 causes, or the theory can not be applied to the two regions. Lastly, if the 

 forests protect us from floods, why did they not do so in 1774, 1789, 1792, 



