398 



THERMAL WATEES OF BATH. 



[Ch. XVII. 



by the expansive force of heat and steam 



pressure 



waters of Bath.— 

 example of mineral 



The 



hot springs of Bath may 



a variety of ingredients 

 springs. 



met 



in thermal 



Their mean temperature is 120° Fahr., which is not 

 only much above that of any other springs in England, but is 

 exceptionally high in Europe, when we take into account 

 their great distance from any region of active or extinct vol- 

 canos, or of violent earthquakes. Thus they are 400 miles 

 distant from the Eifel volcanos, lying E.S.E. of them, and 

 440 miles from those of Anvergne, which lie to the S.E. The 

 daily evolution of nitrogen gas amounts, according to Dr. 



volume 



This 



gas 



om 



om 



The other substances held in solution are the sulphates of 

 lime and of soda, and the chlorides of sodium and magnesium. 

 As the uniformity of temperature at all seasons of the year is 



l 



emarkable in this, and in thermal springs generally, so is 

 the uniformity of the discharge of water from century to 



century, and of the 



miner 



ingredients held in solution. 



If we compare the hot water forced up by springs from 

 below to the vast clouds of aqueous vapour evolved for da}^s, 

 or weeks in succession, from volcanic craters in eruption, so 

 we may liken the voluminous masses of solid matter raised 

 from great depths by the hot spring, to the lava which the 

 volcano pours out on the surface. There is more analogy 

 in the work done by the two agents, in raising up matter from 

 great depths, than is commonly imagined. The waters of 

 Bath are not conspicuous among European hot springs for 

 the quantity of foreign matter which they contain, yet Pro- 

 fessor Ramsay has calculated that, if the mineral ingredients 

 which they pour out were solidified, they would form in one 

 year a square column nine feet in diameter, and no less than 

 140 feet in height. All this matter is now quietly conveyed 



stream 



h 



and by the Avon to the sea ; but if, instead of being thus re- 

 moved, it were deposited round the orifice of eruption, like 



C* 



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s. 



the 



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elap 3 



(say) 

 betff 



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sea 







inter 



Ga 

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 fort 



in g* 



acid 



calcj 

 pone 



seer* 

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 boni 

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 and 

 mm 

 tufa 

 A 

 linit 

 nW 

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 tliei 



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