of removing Matter from Solution in Water. 



25 



Results of Filtration through Sand at the Chelsea Waterworks, 

 Table I.— September 12, 1855. 



Table II.— December 29, 1855. 



Table III.— May 10, 1856. 



By these analytical results (if entitled to confidence, and I 

 may state that all due care and attention was given to ensure 

 their accuracy) it is shown that this process of mere sand fil- 

 tration is one of more importance, and of a more peculiar and 

 interesting character, than has generally been supposed. 



It has been asserted as a principle that sand filtration can 



