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 : 



Oxygen . . . 

 Nitrogen . 

 Carbonic acid . 



Percentage. 

 25-046 

 54-211 

 20-743 



Proportion. 



100 

 216 



80 



loo-ooo 



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 : 



f Oxygen . . 

 5 \ Nitrogen 

 ( Carbonic acid 



Per cent. 

 29-10 

 52-87 

 18-03 



Proportion. 

 100 

 182 

 62 



General average. 

 25-046 100 



54-211 216 



20-743 83 



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. 



