WHY SALTS AKE FOUXD IN STAGNANT POOLS. 97 



The presence of potash, pliosplioric acid, iron, and 

 sulphuric acid, in the water" of stagnant pools, is easily 

 explained. 



Li a stagnant pool or bog are gradually collected the 

 remains of dead generations of plants, the roots of wliicli 

 have drawn a quantity of mineral matter from a certain 

 depth of the soil. These vegetable remains imdergo 

 decomposition at the bottom of the pools, and their 

 inorganic elements, or ash-constituents, are dissolved by 

 the aid of carbonic acid, and perhaps also of organic 

 acids. They remain dissolved in the water, when the 

 surrounding mud and the earth in contact with this 

 solution have been completely saturated with them. 



Scherer found in the three wells at Brllckenau all the 

 substances contained in the Avater above-mentioned, of 

 the Botanic Garden pond, besides acetic, formic, but}T.ic 

 and propionic acids. The mountains all around Briickenau 

 are formed of variegated sandstone {Bunter sandstein) ; 

 the vegetation of the whole surrounding country is most 

 luxuriant, resembling tlie jj^meval forests ; there are 

 numerous oak-lands and beech-lands, with trees nearly 

 a thousand years old. Hence Scherer is led to attribute 



Lime 35-000 



Magnesia 12-264 



Chloride of sodium .... 10-100 



Potash 3-970 



Soda 0-471 



Sesquioxide of iron with akimina . . 0-721 



Phosphoric acid ..... 2-G19 



Sulphuric acid ..... 8-271 



Silicic acid 3-240 



Incombustible constituents . . . 76-656 

 Water lost 23-344 



100-000 

 H 



