PURIFICATION OF WATER FOR DRINKING PURPOSES 199 



Finely Sifted and Sterilised Ahiminium Oxide 

 Temperature at which vessels were kept = 9° C 



' still slightly turbid after 20 hours. 



= Still slightly turbid after 30 hours. 



Pulverised and Sterilised Brich 

 Temperature at which vessels were kept = 7° C. 



^ Liquid was clear after 2\ hours. 



^ Liquid was almost clear after 7\ hours. 



Pulverised and Finely Sifted Sterilised Vegetable Charcoal 

 Temperature at which vessels were kept = 7° C. 



^ Slightly turbid after 20 hours. 



' Slightly turbid after 30 hours. 



