384 



which is, indeed, no snnall deposition on the area of 1 sq. cm. 

 In the Danish lake Fure-Sø with an area of 9 sq. km. it would 

 correspond very nearly to 3000 tons of lime pro year. 



In the summer of 1903 I examined the tensions of carbonic 

 acid in the waters of the Fure-Sø and obtained the following, 

 results : 



The analyses show that the tension of carbonic acid in 

 the surface of the lake is higher than that of the atmosphere. 



a deposit is directly formed by the evasion of COj to the atmo- 

 sphere. Possibly a very great part may be formed by organic forces, 

 but it is due solely to the removal of carbonic acid by the atmosphere 

 that this part is not redissolved. 



