56 WARM SPRINGS. 



fluence on the properties of the salts which it dis- 

 solves, and comparatively little on the quantity of 

 them, that is taken up. Thus we find carbonic acid in 

 springs of very different temperature, hot as well 

 as cold. The Carlsbad "Sprudel" at 75° C. 

 (167° P.), and the Nauheim spring-well at 30° C. 

 (86° P.) bring up a large quantity of carbonic acid. 

 This gas however can only be kept dissolved in 

 any considerable quantity at the surface of the 

 earth, by cold water; so that those that are 

 specially called carbonated springs, are always of a 

 low temperature; as that of Selters, at 16°'8 C. 

 (62°-24 P.) ; that of Pyrmont, at 13°'75 C. 

 (56°'75P.); of Schwalheim atl2°.5C. (54°'5P.); 

 Rohitsch at 11°'25 C. (52°'25 P.); Geilnau 

 at 11° C. (51°*8 P.); Pachingen at 10° C. (50°P.); 

 Schwalbach at 10° C. &c. Most carbonated 

 waters contain some carbonate of iron, which, like 

 carbonate of lime, is soluble in water charged with 

 carbonic acid. When the waters have the peculiar 

 taste of iron very strongly, as is the case with the 

 waters of Pyrmont, Langenschwalbach, Ro- 

 hitsch, Spa, &c, they are called Chalyheates. 



Among the springs which have a strong taste of 

 the sulphides of the alkali-metals, or of sulphuretted 

 hydrogen — springs which are called sulphur- 

 waters — some are found of a very high, and others 

 of a low temperature. The famous sulphur-springs 

 at Aix-la-Chapelle have a temperature of from 



