374 



Puh. Pngef Sound Biol. Sia. 



Vol. 2, No. 54 



that the pH of the water of the Black Sea fell very rapidly at a depth 

 of about 180 meters, always being accompanied by a rapid fall of the 

 oxygen content of the water; this, however, was the only locality at which 

 he found a direct relation between the pH and the oxygen content of the 

 sea-water. 



4. Hydrogen-ion concentration and oxygen content of 

 water at different depths 



A few determinations were made at different depths which indicate 

 that there is no uniformity with the variation of the hydrogen-ion con- 

 centration and depth. This does not agree with observations of other 



Table 2. The variations in the h if drog en-ion concentration and o.riif/en 

 content of the sea-tcater with depth. 



