110 THE MOUNTAIN. 



The water of hills and mountains differs in quality, according as it 

 niters through banks of pure rock, of schist, of quartz, or of sand, 

 from all which substances it can scarcely derive any property what- 

 ever; or as it flows over beds of potter's earth, which it neither 

 draws along with it nor dissolves ; or, lastly, as it traverses ground 

 which is calcareous, marly, gypseous, impregnated with magnesia, 

 salt, or bitumen. Waters of the kind last mentioned are always very 

 much mixed with heterogeneous substances, and for the greatest part 

 of the year are hard, turbid, and unwholesome, at least if daily used. 

 Hippocrates, Homer, and Plutarch have long ago condemned the use 

 of them. Those waters which have clayey bottoms are most com- 

 mon ; they unite those qualities which are essential to salubrity. 

 Those which flow from the hard rock are still more pure and limpid, 

 as they must undergo a process of filtration in wearing their way 

 over a stony bed. 



MALTE-BRUN. 



