240 M. Arago on Artesian Wells 



well into them, the extreme variations which the seasons induce 

 are. prevented. This experiment, it is said, has entirely suc- 

 ceeded in the ponds of St Gratien, near to Montmorenci. 



Sometimes Pits are sunk for the purpose of transmitting into the inte- 

 rior of the earth, water, retained at the surface by strata of imper- 

 meable clay or stone, and thereby rendering extensive districts mere 

 morasses, unfit for cultivation. 



The pits by which descend into the interior of the earth those 

 quantities of water, which, without this expedient, remain on 

 the surface, may be called negative artesian wells. Necessity, 

 the mother of so many important inventions, early suggested to 

 mankind the idea of imitating nature in this point. 



The plain of Paluns, near Marseilles, used to be a great 

 morass. It appealed impossible to drain it by the help of the 

 common surface channels. King Rene, however, caused a great 

 number of pits or drain- wells to be sunk, which are known in the 

 proven^al language by the name oi embugs (funnels).* These 

 pits transmitted, and now transmit into the permeable strata si- 

 tuated at a certain depth, those waters which made the whole 

 country a barren waste. It is positively stated that it is the 

 waters taken down by these embiigs of Paluns, which, after a 

 subterranean course, form the projecting fountains of the port of 

 Mion, near to Cassis. 



The river Orbe, in the Jura, wliich descends from the lake of the 

 Rousses, conveys into lake Joux much more water than evapo- 

 ration removes from it. This latter lake, whence there issues no 

 river, preserves notwithstanding a stated elevation which is nearly 

 uniform. " It is," says Saussure, " because nature has pro- 

 vided for these waters subterranean issues, by which they are en- 

 gulfed and disappear. * * * * As it is of the greatest conse- 

 quence for the inhabitants of this valley to preserve these natu- 

 ral drains, without which their arable lands and their habitations 

 would be inimediately overflowed, they preserve them with the 

 greatest possible care ; and when they perceive that they do not 

 take off the water with sufficient velocity, tJiey themselves open 



• It is the property of absorbing, of drinking up the surface waters, pos- 

 sessed by certain natural and artificial openings, which has given the names of 

 boiUout, ofbetoirs or boitards, to these drain- wells in certain districts.] 



