Chap. 8.] Celebrated Mineral Waters. 515 



the reader for information on this point to what was 

 ftated when treating of the combinations of filver and 

 mercury with the different mineral acids. 



By tin&ure of turnfole the predominance either of 

 an alkali or an acid is difcovered : as vegetable blues 

 are turned red by acids, and green by alkalies. Acid 

 of fugar is a very fenfible tell of lime, when com- 

 bined with the fparry or acetous acids. A folution of 

 arfenic in the marine acid will precipitate fulphur from 

 water, in which it is held difiblved by means of carbo* 

 nic acid. It may be added, that white arfenic becomes 

 yellow if immerfed in water containing hepatic gas ; 

 and a piece of polifhed iron will receive a copper- 

 colour from water in which copper is diflblved. If a 

 mineral water is found to contain a fixed alkali, it may 

 be determined whether it is the vegetable or mineral 

 alkali by means of vinegar. With vegetable alkali 

 vinegar yields a deliquefcent fait; with the mineral, 

 foliated cryftals. 



It may be proper briefly to notice the compofition 

 and obvious properties of fome of the moft celebrated 

 mineral waters, and the diforders in which they are 

 fuppofed to have moft efficacy. 



f AIX-LA-CHAPELLE. This place has long been 

 famous for its hot fulphureous waters and baths. They 

 arife from feveral fources, which fupply eight baths 

 conftrucled in different parts of the town. Thefe 

 waters near the fources are clear and pellucid, and 

 have a ftrong fulphureous fmell refembling the wafh- 

 ings of a foul gun j but they lofe this fmell by expo- 

 fure to air. Their tafte is faline, bitter, and urinous. 

 They do not contain iron. They are alfo neutral 

 near the fountain, but afterwards are manifeftly, and 

 pretty ftrongly alkaline, infomuch that cloatfcs may be 

 1,1 2 wafhed 



