924 M. Arago on Artesian Wells 



There is often in these stratified formations, distinct sheets of 

 xmier at diffkrknt depths. The works which have been 

 undertaken in search of coal, near to Saint-Nicolas d'Aliermont, 

 near Dieppe, have proved that there are seven great sheets of 

 water. Their respective positions are as follows : 



1st sheet of water at a depth of 76 feet. 



2d SOT ... 



3d 537 ... 



4th 645... 



5th 768 ... 



6th 880 ... 



7th 1030 ... 



All these collections of water rushed with great force towards 

 the surface. 



During the boring of the wells of the Port Saint Ouen, the 

 Messrs Flachat encountered five very distinct sheets of water, 

 all of which had the tendency to rise. 



The 1st at the depth of 108 feet. ^ 



... 2d 138 ... 



... 3d 156 .. 



... 4th 184 ... 



... 5th 206 ... 



The same engineers encountered four of these reservoirs of 

 water, whilst boring to the depth of 200 feet at Saint Denis, 

 close to the Place de la Paste aux Chevaux. 



At Tours, the three pools, all having a tendency to ascend, 

 which were met with by M. Degousee, were found below La 

 Place de la CatMdrale, 



The 1st at the depth of 292 feet. 



... 2d 340 ... 



... 3d 383 ... 



The sinking of pits in the neighbourhood of London has 

 brought the same truth to light ; and the same remark mio-ht 

 be made respecting the United States of America. 



Sometimes in the heart of these stratified rocks, besides pools of loafer 

 which are stationnry, there are water-courses, true subterranean 

 river s, which flow rapidly i?i the empty spaces found amongst 

 tlie impermeable rocks. 



By subterranean water-courses I do not here wish to designate 

 either the rivers, such as the Poick of Carniola, which are en- 



