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The Decrease of Water Surface. 



The evidences of the apparent snbsidence of the water 

 level upon the earth's surface, have been familiar to scien- 

 tific observers for many centuries ; and various theories 

 have been advanced, from time to time, to account for it. 

 Aristotle, Zanthus, Omar in the 10th Century, Leibnitz, 

 Calcius, Vallisneri, Linn^us, Buitbn and Gessner are 

 among those who have noted the diminished extent of 

 water surface upon the earth. Linuieus and some others 

 accepted the theory of Leibnitz, that the Universal Ocean 

 was received into cavern's which opened in the earth's crust. 



There seems to have been no expression of similar views 

 durin tr the past century. * Humboldt says : •' We must not 

 overlook the possibility of a diminution of the quantity of 

 water, and a constant depression of the level of the 

 seas, * -'^ but in the actual condition of our planet there 

 is no direct evidence of a real continuous increase or de- 

 crease of the sea, and we have no proof of any gradual 

 change of its level." (Cosmos 11. p .) 



As far back as 1692, Ray wondered, on the other hand, 

 why the earth did not proceed more rapidly toward a 

 general submersion when so nmch matter was carried into 

 it by rivers and undermined in sea cliffs, which tended con- 

 stantly to raise the surface of the waters. Lyell adds: 

 "Certainly no deposition of sedinfent can occur without 

 the displacement of a quantity of water equal in volume, 

 which will raise the sea even to the antipodes." 



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