214 M. Arago on Artesian Wells 



This example will be sufficient, I imagine, to demonstrate 

 how little the consideration of the rivers themselves, when at- 

 tentively studied, justifies the theories of ancient naturalists. 

 The abundant liquid currents which they unceasingly carry to- 

 wards the sea, from the interior of continents, are universally 

 but a small proportion of the mass of rain-water which annually 

 falls in the surrounding country. There is not here, therefore, 

 any more than in the circumstances of springs, good ground for 

 assigning any place to the central vapours in the explication of 

 the phenomena. 



This numerical discussion will likewise serve to refute those 

 who have recently employed themselves in seeking for the sources 

 of these springs in those interior basins in tahich is to be found 

 that liquid mass which still holds the earthy sediments in sics- 

 pension or solution. This hypothesis evidently merits no at- 

 tention, until it is first proved that the rain-water is not suffi- 

 cient to explain the phenomena ; and till it is also proved that 

 the same water does not penetrate to great depths in the crust 

 of the earth. But, after what has already been said, a tolerably 

 decided judgment may already be formed on both these points. 

 In thus dedicating a few words to this novel theory, I wish to 

 supply some comfort to those persons who are possessed with 

 the apprehensions of the approaching drying up of these interior 

 basins, and consequently with the failure of all our springs and 

 wells. If, on the contrary, it is established that these fountains 

 are fed by the waters from the atmosphere, then it is evident 

 that they can withhold or vary their supplies only in accordance 

 with the variations of the rain, and dew, and snow, and of eva- 

 poration. 



We have here said nothing of earthquakes, which, it is true, 

 by violently breaking up the different strata of the crust of our 

 Mobe, and tossing them hither and thither, may, in certain situa- 

 tions, change the position and velocity of subterranean currents. 

 But, as the possibiHty of these shocks does not prevent us from 

 buildino- our mansions, no more ought it to interfere with us 

 when we are sinking our wells. 



count ; and besides, it may happen that tlie spring at Rungis is itself fed by 

 •some subterranean stream which has a distinct origin. 



