Chap. 8.] Mineral Waters. 513 



ftances called re- agents, to difcover the contents of 

 mineral waters, it may in general be remarked, that 

 this mode is kfs certain than evaporation ; the latter 

 method, however, is not free from objections, as the 

 application of heat ta any body not unfrequently de- 

 ranges the previous ftate of combination among its 

 component principles. The chemical tefts beft adapt- 

 ed to the difcovery of the contents of mineral waters 

 are the following : lime, volatile alkali, fixed alkalies, 

 vitriolic acid, tincture of turnfole, muriated barytes, 

 acid of fugar, arfenic, Pruffian alkali, and the nitrous 

 folutions of filver and mercury. When it is propofed 

 to difcover the contents of a mineral water, it is beft 

 to begin with fuch tefts as, are leaft capable of altering 

 it, and afterwards, having obferved their effects, to 

 proceed to complete the analyfis by tefts which have 

 a more extenfive influence. Lime water feizes the 

 carbonic acid, and forms a precipitate of chalk ; it alfo 

 precipitates falts with the bafis of clay and magnefia, 

 as well as the metallic falts. If after mixing an equal 

 quantity of lime water with a mineral water, no pre- 

 cipitation takes place in twenty-four hours, it may be 

 concluded, that it contains neither carbonic acid at 

 liberty, nor a combination of that acid with fixed alka- 

 li, nor earthy falts with the bafis of aluminous earth or 

 inagnefia, nor any metallic fait. But if* a precipitation 

 takes place on the addition of lime water, the next ftep 

 is to examine the properties of the precipitated matter ; 

 if it has the properties of chalk, fuch as infipidity, the 

 producing of an effervefcence with vitriolic acid, and 

 forming with it a compound nearly infolublc in water, 

 that is gypfum, it mud be concluded that the water 

 contained carbonic acid, which, uniting with the lime 

 of the lime water, produced chalk. I on the con- 

 VOL. IJ. \ 1 trary. 



