

<tf 





N 



- 



387 





% 



V ' 



V 4 



ti 





a 



i 



- ■ -.1 



i 



hen 



tit 

 lib 



ei 



:th 





a 



i to- 

 ne i 



ft 

 ho* 



its 



CHAPTER XVII. 



PHENOMENA OF SPEINGS. 



ORIGIN OF SPRINGS — ARTESIAN WELLS BORINGS AT PARIS — LIVE FISH 



RISING IN THE ARTESIAN WELLS IN THE SAHARA DISTINCT CAUSES BY WHICH 



MINERAL AND THERMAL WATERS MAY BE RAISED TO THE SURFACE THEIR 



CONNECTION WITH VOLCANIC AGENCY — THERMAL WATERS OF BATH CALCA- 

 REOUS SPRINGS — TRAVERTIN OF THE ELSA — BATHS OF SAN VIGNONE AND 

 OF SAN FILIPPO, NEAR RADICOFANI — SPHEROIDAL STRUCTURE IN TRAVERTIN 



LAKE OF THE SOLFATARA, NEAR ROME TRAVERTIN AT CASCADE OF 



TIVOLI — GYPSEOUS, SILICEOUS, AND FERRUGINOUS SPRINGS BRINE SPRINGS 



CARBONATED SPRINGS DISINTEGRATION OF GRANITE IN AUVERGNE 



PETROLEUM SPRINGS — PITCH LAKE OF TRINIDAD. 



i 



The action of running water on the sur- 

 iving been considered, we niay next turn 



our attention to what may be termed ' the subterranean 

 drainage/ or the phenomena of springs. Every one is familiar 

 with the fact, that certain porous soils, such as loose sand 

 and gravel, absorb water with rapidity, and that the ground 

 composed of them soon dries up after heavy showers. If a 

 well be sunk in such soils, we often penetrate to considerable 

 depths before we meet with water ; but this is usually found 

 on our approaching some lower part of the porous formation, 

 where it rests on an impervious bed; for here the water, 



e to make its way downwards in a direct line, accumu- 

 as in a reservoir, and is ready to ooze out into any 

 opening which may be made, in the same manner as we see 

 the salt water filtrate into, and fill, any hollow which we dig 

 in the sands of the shore at low tide. 



The facility with which water can percolate loose and 

 gravelly soils is clearly illustrated by the effect of the tides 



lates 



Richmond 



The river, 



in this part of its course, flows through a bed of gravel over- 



c c 2 



