112 



rtg« . 



Graph •aftviag ra^anarvttlon in decrt&ainc o on cant rations 



of fter the *at ar ha4 baen aerate . 



Heavy perpendicular lino oarka time of entrance of 



oxygen. 



Or II oat a * f, regenerated. Abaci aa a m time in laye, 



Kuabere at enia of curves ■ 00.O3 eriftionally in 



1 liter of the water. 



Frow lata of Tab la 33» 



