Mineral Waters. 267 



acid, which, when used for this purpose, must 

 be saturated with as much lead as it can possibly 

 dissolve. On adding this, the water, if it con- 

 tains lime, is immediately turned muddy. If, 

 upon examining any water, we find by the syrup 

 of violets that it doss not contain an alkaline 

 salt in its separate state, and yet find that the 

 lead is precipitated, we have reason to conclude 

 that the precipitation is occasioned in a great 

 measure by lime. It is hardly possible to de- 

 termine the quantity of this substance ; and it is 

 best to trust to the examination of the matter 

 that remains after the evaporation of a large 

 quantity of water. 



Bitumen is always discernible in water, by its 

 appearance, smell, and taste. There is also an- 

 other way of judging of it : it has little or no 

 solubility in water, but floats on its surface: if 

 any part of it is dissolved, it may be separated 

 by evaporation. 



Besides these trials, by which several of these 

 substances may be discerned in their separate 

 state, we have many experiments by which we 

 can discover them when combined with other 

 bodies. None of the metals are contained in 

 water in a separate state; but alkalies, earths, 

 and metals are contained in water in a state of 

 combination, chiefly with the sulphuric acid. 

 There are experiments far discovering its exist- 

 ence and quantity, with whatever body it is 

 joined. The solution of lead in the acetic acid 



