Sect. VI.] Hydrology, t55 



But among the discoveries and improvements of 

 thtj last age, which belong to this head, the most 

 important are the numerous and very useful inves- 

 tigations of Mineral WaUrs^ which were pursued 

 with great success during that period. It is 

 evident that our knowledge of the properties and 

 effects of mineral waters must in general keep 

 pace with the progress of chemical science; for 

 whicJi reason the early writers on thus subject were 

 in a great measure destitute of the best means of 

 pursuing their inquiries. 



Mr. Boyle may be considered as tlie first person 

 wdio pointed out the method of examining mineral 

 w^aters. He first ascertained the existence of air 

 in water, and directed to a number of tests by- 

 means of which conjectures might be made con- 

 cerning the saline bodies which the water examin- 

 ed held in solution. He was soon followed hy du 

 Clos of France, by Hierne of Sweden, and by seve- 

 ral other philosophers in different parts of Europe, 

 who made considerable additions to the tests em- 

 ployed and the facts ascertained by Bo\'ie. In 

 1726 Boulduc pointed out a method of precipitat- . 

 ing sevei^l of the saline contents of water by means 

 of alcohol. But it was not till after the discovery 

 of carbonic acid by Dr. Black, that any great pro- 

 gress w^as made in ascertaining the composition of 

 mineral waters. That subtile acid, \Vhich is so 

 often contained in them, and which serves as a 

 ve\y powerful solvent to many of the eartiis, and 

 even of metallic bodies, had thwarted all the at- 

 tempts of former chemists to detect the composi- 

 tion of these liquids. Since the discovery of that 

 acid, the analysis of minerar waters has advanced 



