7:i 



This iiidic-ilcs tluit the ;is(cii(lini; (■iirrciits (-.•irricd sumc of the oxygenloss 

 \\;ilcr ffoiii llic lidtldin low.iid tlic snii";i(<'. while licyoiid the influence of 

 Ihis \("ilif;il ciiricnl liic w.ilcr ilcscciKicd (■.•iiryiim' with it oxygen which it 

 iiad received at Ihe smtaee fr.nii liie air. I'.olh of tlu'se currents were more 

 or less mixed witli llie waler Ilial iioniially lay at the different levels. 



The aei-onipanyiiiii <uives iiidieale the coiiditioiis in lidO and also the con- 

 diiioiis on the same date in TJlL'. 



The usual method of aeiatiiiu sloi-e<l waters is to spray the water into 

 the air or allow it to tlow <i\cr ruhhle <>v an interrupted spillway. The ad- 

 Nanlaire in I lie method Jusi descrihed is that it takes very much less energy 

 to carry the air iidn the water than it does to force the water into the air. 



Figiire 2. Broken lines are the curves for oxygen and temperature for 

 September 2?,. 1912: the solid lines for Sei>temher 20. 1919. T=temperature 

 Centigrade. 0=cc. of oxygen per liter. Station I is at the air outlet. Sta- 

 tion II is 150 ft. up the pond from Station I. 



