152 Dr. Du Riehe Preller — Mineral Springs of Baden. 



The springs have a temperature of 46° 0. (115° F.), and are not 

 affected by the rise or fall of the river Li m mat, but vary according 

 to the rainfall at different seasons, a fact which shows that they are 

 derived from atmospheric water percolating through the various strata. 

 The fact that the chemical composition of all the twenty-one springs 

 is fairly uniform, warrants the conclusion that they all rise from one 

 source or collecting-basin. Assuming the temperature of the atmo- 

 spheric water at the surface to be 10° C, and the increase of 

 temperature to be 1° C. every 30 metres, the temperature of the 

 Baden springs corresponds to a depth of the subterranean reservoir 

 of (46 - 10) x 30 = 1,080 m., or about 3,500 ft. The probable seat 

 of the reservoir is therefore not below the Keuper or upper member 

 of the Trias. The average yield of the springs is in the aggregate 

 no less than 1,000,000 litres (222,000 gallons) in 24 hours. Both 

 in yield and temperature, the Baden springs vie with other celebrated 

 thermal springs, such as those of Pfavers and Aix-les-Baius, which 

 have a temperature of 36° C. (97° F.) and 45° C. (113° F.) 

 respectively. 



2. Birmensdorf and Mullingen, 340 metres (1,115 ft.) above sea- 

 level. These are cold springs, containing chiefly sulphate of 

 magnesium, sulphate of sodium, and sulphate of calcium, from the 

 dolomitic and gypsum strata. In addition to the natural spiings, 

 mineral water is produced by leaching the strata in tanks formed in 

 pits at a depth of 100 metres (330 ft.) below the surface. The 

 springs and tanks are capable of yielding about 1,000,000 litres 

 (220,000 gallons) per annum, but the abundance of gypsum dykes, 

 which have already been worked for more than 70 years, is such that 

 the production can be largely increased. 



The Birmensdorf water has a temperature of 15° C. (59° F.), and 

 a specific gravity of 1*1 7. In mineral composition it compares as 

 follows with the well-known similar waters of Friedrichshall and 

 Hunyadi Janos : — 



The mineral water of Mullingen is very similar to that of 

 Birmensdorf, being derived from the same Triassic and Jurassic 

 strata which are intersected by the river Beuss. 



3. Schinznach, 343 metres (1,125 ft.) above sea-level. This is an 

 abundant thermal spring, somewhat similar to the springs of Baden, 

 and rises from the dolomitic and gypsum strata about 30 ft. below 

 the surface. It contains, in 1,000 parts : carbonate of calcium, 025 ; 

 carbonate of magnesium, 0-12; sulphate of calcium, 1*10; and some 

 free sulphuretted hydrogen. The spring has a temperature of 35° C 



