72 THE PLANT. 



alumina ; yet we also know that this substance, in the 

 form in which it occurs in all fertile soils, is not soluble 

 in pure water, or water containing carbonic acid ; and 

 that it cannot be detected in any other plant growing 

 on the same soil by the side of the club-moss. In like 

 manner, Schultz-Fleeth could not discover in the water 

 in which Arundo phragmites (one of the plants most 

 abounding in silicic acid) was growing, sufficient silicic 

 acid to yield a ponderable amount in the composition 

 of 1000 parts of the water. 



