M.Stifft on the Ongln of' Mineral Springs. 293 



7. The known fact, that very often volcanic eruptions are ac- 

 companied by the bursting out of new thermal springs, which 

 sometimes cease when the volcanic agency becomes feeble, some- 

 times return periodically like the eruptions themselves. 

 ' Besides this, from all those districts which bear the traces of for- 

 mer volcanic activity, there also issue mineral springs which pre- 

 sent in a greater or less degree those characters which distinguish 

 volcanic products. Sulphureous springs, for instance, appear in 

 those districts where sulphureous sublimations are a product 

 of volcanic activity. Przystanowski considers beds of sulphur 

 as the cause of volcanoes ; to me they seem to be merely the 

 sublimations consequent upon their activity. If only gas rose 

 from the orifices of our sulphureous springs, we would see the for- 

 mation of similar sulphur beds. In this way I explain the ex- 

 istence of native sulphur which is found at Ems between the 

 greywacke strata from which the thermal waters issue, but in 

 situations where no springs exist. It does not follow from these 

 principles that we are to exclude the action of atmospheric causes. 

 On the contrary, I am of opinion, that by far the greater quantity 

 of the water of hot springs, and all that of cold springs, is derived 

 from the atmosphere, which is conducted by well known modes 

 into the interior of the earth, and unites partly with the water 

 of the matters which go to prove the central focus, partly with- 

 out reaching as far as the focus, merely takes up the exhalations 

 and sublimations it finds in its progress, and reissues at the sur- 

 face according to the known laws of hydrostatics, aided no doubt 

 in some measure by the pressure of the ascending cfases. 



This explains why hot springs, with few exceptions, are ge- 

 nerally more powerful, and more strongly impregnated with 

 solid matters than cold, and why they are more independent 

 than the latter on changes of the seasons, weather, &c. The 

 opinion which considers that mineral waters derive their impreg- 

 nation from a solution or lixiviation of the rocks which they tra- 

 verse, assumes, in common with the preceding one, the existence 

 of a central focus, whether it be an active or extinguished vol- 

 cano, or merely the heat still remaining as a consequence of the 

 former fluid state of the earth. The vapours ascending from 

 this centre, according to this theory, prepare the rocks for so^ 

 lution in the water which, penetrate from above, as well as com- 



