402 Prof. Adeney and Mr. Becker : Determination of Rate oj 



VIII. Statement of Results. 



From the figures given in the previous section it is 

 possible to calculate the rate of solution of the gases dealt 

 with, for any conditions of area exposed, depth, or degree o£ 

 saturation, provided that the water is kept uniformly mixed. 



The expression can be put either in the form 



dw 1 



-7— =a — bu\ 

 at 



which gives the rate of solution at any instant, or in the 

 form iv= [w — tv{)(l — e~ bt ), which gives the amount dis- 

 solved at the end of any given time when w = saturation 

 value and u?i == amount of gas in solution initially. For 

 practical purposes it is most convenient to work in per- 

 centages of saturation ; hence the latter equation becomes 



w= (100 — w x ) (1 — e~ bt ), and since 





>=/y 





by substitution 





W=(lj00--Il7 1 )(l- 





as the general equation for any given temperature, and since 

 /varies with temperature according to the equations 



Oxygen f='0096 (T-237) 



Nitrogen /=*0103 (T— 240) 



Air /='0099(T— 239), 



the corresponding general equation for each gas by sub- 

 stituting these expressions in the formulae is obtained, 

 thus : — 



for Oxygen w= (100-ioJ [l-,-° 096(T - 237) ^j 



„ Nitrogen M = (100- Wl ) [1 _ e -™W-™)~tj 



„ Air ic=(100-w 1 )[l-e--° m{T - 23d) P]. 



As an example of the use of these formulae, consider the 

 question of the dissolved oxygen in 1000 c.c. water, area 

 exposed being 100 sq. cm., temp. 2°' 5 0., and initial gas- 



