ARTESIAN WELLS. 423 



and will afford abundant supplies of water for agricultural 

 and domestic purposes and sometimes even for moving ma- 

 chinery. The quantity of water thus obtained in Artois is 

 often sufficient to turn the wheels of Corn-mills. 



In the Tertiary basin of Perpignan and the chalk of 

 Tours, there are almost subterranean rivers having enor- 

 mous upward pressure. The Water of an Artesian well in 

 Roussillon rises from 30 to 50 feet above the surface. At 

 Perpignan and Tours, M. Arago states that the water rushes 

 up with so much force, that a Cannon-ball placed in the 

 Pipe of an Artesian well is violently ejected by the ascend- 

 ing stream. 



In some places application has been made to economical 

 purposes, of the higher temperature of the water rising 

 from great depths. In Wurtemberg Von Bruckmann has 

 applied the warm water of Artesian wells to heat a paper 

 manufactory at Heilbronn, and to prevent the freezing of 

 common water around his mill wheels. The same practice 

 is also adopted in Alsace, and at Constadt near Stuttgard. 

 It has even been proposed to apply the heat of ascending 

 springs to the warming of green houses. Artesian wells 



These theoretical Results can never occur to the extent here represented, 

 in consequence of the intersections of the strata by valleys of Denudation, 

 the irregular interposition of Faults, and the varying condition of the matter 

 composing Dikes, 



If a valley were excavated in the stratum M below A", the water of this 

 stratum would overflow into the bottom of this valley, and would never rise 

 on tlie side of the fault so high as the level H. 



Wherever the contact of the Dike H, L, with the strata M, N, O, P, Q, R, 

 that are intersected by it, is imperfect, an issue is formed, through which the 

 water from these inclined strata will be discharged at the surface by a na- 

 tural Artesian well ; hence a series of Artesian springs will mark the line 

 of contact of the Dike with the fractured edges of tlic strata from which 

 tlie water rises, and the level of the water within these strata will be always 

 approximating to that of the springs at H ; but as the permeability of Dikes 

 varies in different parts of their course, their effect in sustaining water with- 

 in the strata adjacent to them, must be irregular, and the water line within 

 these strata will vary according to circumstances, between the highest pos- 

 sible levels, A, B, C, D, E, and the lowest possible level H. 



