344 Scientific Proceedings, Royal Dublin Society. 



experiments, without allowing the surface exposed to become indefinite : hence 



it is of interest to compare this with the rate of solution as determined in 



previous experiments.^ 



The rate of solution of oxygen into air-free water has been found by a 



totally different method to be '0161 c.c. per minute per square centimetre of 



area exposed. Hence for the oxygen in the atmosphere the rate should 



21 

 be ■0161 X — - = '0034 c.c. per minute under similar conditions, since the 



rate of solution has been shown to be proportional to the partial pressure. 



This value is more than twice as great as the maximum value attained in 

 these experiments (-0016), showing that tlie rate of mixing that was reached 

 under these circumstances was not so rapid as that obtaining in the 

 experiments referred to. This was to be expected, since in those experiments 

 the water was exposed to the oxygen in very thin layers, and very perfectly 

 mixed immediately afterwards. However, the fact that the two values come 

 so near each other shows that with more perfect stirring arrangements it 

 might be possible to approximate very closely to the maximum rate of 

 solution. 



These experiments therefore afford a connecting link between the 

 conditions obtaining in the work referred to and those obtaining in nature. 

 They also emphasize the important part played by mixing of the water in 

 determining the rate of solution. It will be seen on reference to the table 

 that very gentle stirring of the under layers of the water increases the rate of 

 solution as much as twenty-fold as compared with stationary water. This 

 bears out the view put forward previously,^ that the rate of solution of air 

 by water under ordinary conditions is largely determined by the rate of 

 mixing. Experiments are being continued with this apparatus ; and it is 

 hoped to publish further results in the future. 



Chemical Department, 



Royal College of Science, Dubllm. 



' Adeney and Becker: Scientific Proc. R.D.S., xv, [>. 625. 1919. 

 2 Adeney and Becker: Scientific Proc. R.D.S., xvi, p. 143. 1920. 



