AcENicy, Leonard, and Hichaedson — Aeration of Water. 



27 



concentration of about 1 per cent, of sodium cliloride. Tlie curves obtained are 

 given in fig. 4. 



65 



^ 

 ^ 



o / \ 



/ o 



% NaCl. 



Fig. 4. — Relation between NaCl concentration and downward "streaming" of dissolved Nitrogen to 

 depths of 200 cms. through solutions of thut salt. 



Conclusions. 



The following conclusions may be drawn from the experimental results obtained 

 in this investigation : — 



1. The aeration of quiescent bodies of water, fresh and salt, under natural 

 conditions is effected by a process of mixing of the exposed layer with the 

 unexposed portions of the water to depths of at least 10 feet. 



2. The process of mixing is caused by the downward " streaming " by the 

 constantly changing layer of water exposed to tlie air. This downward "streaming" 

 sets up a process of mixing certainly to depths of 10 feet, and in all probability to 

 much greater depths. 



3. The process of mixing set up by the downward " streaming " proceeds more 

 rapidly, and more uniformly downwards, to depths of at least 10 feet, in salt 

 water than in fresh water. 



SCIENT. PECO. R.D.S., VOL. XVII, NO. 3. G 



