506 



THE DEPTHS OF THE SEA. 



[chap. X. 



surface-waters. (2) Analyses of waters below the surface ; and 

 these last may be again subdivided into {a) intermediate, and 

 (6) bottom-waters. 



The total quantity of dissolved gases in sea-water, whether 

 at the surface or below it, was found to average about 2-8 

 volumes in 100 volumes of water. 



The average of thirty analyses of surface-waters made during 

 the expedition gave the following proportions : — 



Percentage, 



Oxygen 25-046 



Nitrogen . . . 54'2U 



Carbonic acid . . . 20'743 



Propoi-tion. 



100 



216 



80 



100-000 

 These were thus distributed over the three cruises, and the 

 maxima and minima of each constituent are thus shown : — 



It is interesting to remark that surface-water contains a 

 greater quantity of oxygen and a less quantity of carbonic acid 

 during the prevalence of strong wind. The following is an 

 average of five analyses made under such conditions : — 



In the two cases which presented the remarkable small 

 minima of carbonic acid with a great excess of oxygen, the 

 water had been accidentally taken from immediately abaft 

 the paddles, where it had been subject to violent agitation 

 in contact with air. 



