124 M. Berzelius on the [Aug. 



About the commencement of last century (in the years 1713 

 and 1727), this calcareous incrustation was suddenly burst open 

 in consequence of the accumulated pressure from within, and the 

 hot water flowed down immediately into the river Tepel. It was 

 determined at that time to bore through the limestone, partly 

 with a view to investigate the cause of these eruptions, and, if 

 possible, to obviate the recurrence of a similar accident, and 

 partly also with the hope of discovering the source in which the 

 apparently inexhaustible supply of water originates. Scarcely 

 had the external crust been broken, when the water rushed out 

 with great violence, and numerous cavities were discovered 

 under it, all of them filled with water, and the partitions be- 

 tween which rested upon a thick calcareous incrustation, simi- 

 lar to the one already penetrated. This also was broken through, 

 and cavities were found beneath it, of exactly the same nature 

 with those already described ; all of them full of water, which 

 was discharged from them with a still greater degree of force, 

 and having another calcareous incrustation for their basis. The 

 opening of the third vault disclosed an immense reservoir of 

 water, which on its first discovery received the name of the 

 Sprudelkessel. These three calcareous layers were in all from 

 one to two yards in thickness, and consisted of a hard body, 

 sometimes alabaster-white, sometimes brownish-coloured and 

 striped, which commonly received the name of Sprudel-stone. 

 They did not rest over one another in a regular concentric man- 

 ner, but constituted numerous unequal cavities, which were 

 separated by the intervening partitions : so that their general 

 arrangement approached considerably to what would be exhi- 

 bited by a number of flat basins of different sizes, when turned 

 upside down, and heaped in an irregular manner over one 

 another. The water in this reservoir was in a state of violent 

 ebullition, and the copious volumes of hot steam which rushed 

 through the opening made in it, completely prevented an accu- 

 rate determination of its extent. Its depth from the outermost 

 crust of limestone was estimated to be between three and four 

 yards, after making allowance for the irregularities of its bot- 

 tom ; but it could not be fathomed in any direction by a rod 60 

 yards in length, and pushed forwards horizontally. Indeed, its 

 great extent may be judged of pretty accurately from the cir- 

 cumstance, that in the greater part of the little town of Carlsbad, 

 one cannot dig to any considerable depth, without meeting the 

 calcareous shell, and when this is penetrated, the hot water 

 instantly rushes up with its customary impetuosity. In many 

 places the carbonic acid gas makes its way through natural 

 clefts in the limestone, in such abundance, as to fill the cellars 

 of the houses ; and in the river Tepel (which flows to some dist- 

 ance immediately over the reservoir), particularly in the neigh- 

 bourhood of the Sprudel, there may be observed a constant 



