194 An Analysis of two Mineral 
these nitrat of silver is instantaneously decomposed, 
and a copious precipitate separates; it is of a dark 
brown or yellow colour, as if from a combination 
of sulphur. Oxygenated muriat of mercury let fall 
a white matter much more plentifully than from the 
solutions of iron. Tartrite of potash is decompos- 
ed, and a fine crystalline substance is separated, 
which is the tartrite of manganese. 
g. This solution is affected by metals in a man- 
ner similar to thé solution of iron. <A piece of 
clean iron becomes quickly covered with rust, and 
an ochry matter separates. If the liquor be boiled 
in a copper vessel, some matter also separates of 
the same colour, and the surface of the vessel is 
- evidently acted upon. Thus the analogy between 
these hepatised solutions and the water of this spring 
appears to me completely established; and it may 
be concluded that this water contains a triple com- 
pound, the basis of which is iron and manganese, 
and the solution of which is effected by hepatic gas. 
X. ORIGIN OF THE MURIATIC ACID. 
The coincidence between the artificial products 
and the natural waters of the spring is sufficiently 
proved: another coincidence remains to be consi- 
dered, much more interesting and rhore unexpected, 
—the coincidence between the hepatised solution of 
iron and the oxygenated muriat of iron. I had al- 
most concluded, from the resemblance between the 
