25 3 An Analtfts of two Mineral Spring! 



veflel, fimilar effects are produced ; a precipitate is formed* 

 and fome copper is diffblved in the water, l. This is readily 

 proved by putting a bright piece of iron into the liquor,' 

 which, in a few hours, acquires a coppery coating *, Lead 

 alfo I have found to be acted upon. 



I examined, with fome minutenefs, the precipitates formed 

 by iron and by copper. 2. The firft is of a yellow colour;' 

 and, though it is riot magnetic, if may be made fo by the 

 flame of a blow-pipe upon charcoal. It conGfts, therefore, 

 of oxyde of iron, either totally or in part ; but whether it is 

 derived from the liquor, or from the iron whi«h was ufed to 

 procure it, cannot be determined by this experiment. But 

 the following obfervation demonftrates, that iron is contained 

 in the water itfelf. 3. The water was boiled in a coppe? 

 veflel, and the precipitate forrned was collected. This is 

 alfo of a yellow colour •, and, expofed to the flame of a blow- 

 pipe on charcoal (like the former precipitate), it became 

 magnetic. It feems alfo to contain copper ; for, precipitating 

 its folution in muriatic acid by ammoniac, the liquor became 

 blue ; the colour however was by no mdans ftrong. 



When the falts of the water have been concentrated by 

 evaporation, copper is acted upon more powerfully ; irrfo 

 much that if 3 Giver fpoon be ufed for the evaporation it is 

 much tarmfhed, and the falts acquire a cupreous tafte and a 

 yellow tinge, though they are colourlefs if the evaporation 

 be made in glaTs. Thefe veftiges'of the copper niuft tre at^ 

 tributed to the alloy of the fpoon. 



The appearances 1 have defcribed farprifed me the- more, 

 as, from the ufe of fome of the common re-agents, I had 

 formed oppofite conclufions. 4. Pruffiat of pot-afh, before 

 the water has been boiled, forms a green cloud, but in a 



* This rem.-.rk evinces the ftrong neceffiiy of a chcjjiical examination of 

 ail the fubftanees ufed as medkincs. It is very common to warm the 

 water 'with a view of quickening its laxative power. It is evident with 

 what caution -effels in which copper is an ingredient fhould be ufed for 

 ihis purpofe; or, rather, with what care they fliould be utterly avoided. 



quantity 



