35 8 An Analyfis of two Mineral Springs 



come dry : the fait may then be procured by lixiviating the 



dry mafs, and cryftallifing the folution. 



Neither fulphat of argill nor oxygenated muriat of mer- 

 cury is at all decompofed by this water. 



XVIII. THE METALLIC SALTS. 



All the appearances which demonftrate the exiftence of 

 peculiar metallic falts in the waters of the new baths are alfo 

 to be found in this : as, the oxydation and folution of metals 

 and a copious precipitate by galls, while the pruffiat of pot- 

 afli is not affected (iv.) : and the fame experiments were 

 repeated to fliew the prefence of the oxygenated falts of iron 

 and mangancfe (v. vn. &c.) with the fame refult, and au- 

 thorife the fame conclufions. Still I believe there is fome 

 difference in regard to thefe falts between the two waters. 

 I. I have already obferved (xvu.) two points of distinction ; 

 and, as the fecond of thofe experiments is probably an in- 

 dication of fulphur, this water feems to be without it. This 

 is confirmed by evaporating the water in a filver veffel, tq 

 which it communicates no ftain. However, 2. Its action 

 on copper is very (irong, fo that, if it be boiled in a copper 

 veflel for a long time, a blue oxvd of copper is fcparated 

 from the veiled. But here, again, there is a difference be- 

 tween this and the former water; for, though copper is dif- 

 folved in it, none can be precipitated on iron in its metallic 

 form, as we have feen (iv. i.). The iron in this water does 

 not feem to be in that high degree of oxygenation that it is 

 in the other. This I infer, becaufe, 3. the precipitate formed 

 by tincture of galls is of a much darker colour, even when 

 the water has been much evaporated : fometimes, when the 

 water has been reduced to half its original bulk, I have re- 

 marked even a very flight green tinge communicated by 

 pruffiat of potaffi, but not till it has been added to it many 

 hours, 



As 



