INJUEY AND EECOVEEY 



109 



lated values; the observed values are shown as points; 

 it will be observed that they lie fairly close to the 

 calculated curve. The figure also shows the calculated 

 values of S; in this case no observed values are given 

 because such values cannot be very precisely determined. 

 This is owing to the fact that the value of S affects only 



"-, in Ca Ch 



S in Ca CU 



""*-. 



-x-.. 



in Na Cl 



S in Na Cl 



200 400 eOOmin. 



Fia. 43. — Curres showing the ralues of + 10 in NaCl (upper UDbroken line) and in CaC 

 (upper dotted line); also the values of iS in NaCl (lower unbroken line) and in CaCli (lower 

 dotted line). The ordinates give the values of O; these must be multiplied by 6.75 to obtain 

 the values of 8. The observed points represent the average of eight or more experiments ; 

 probable error of the mean less than 10% of the mean. 



the speed of recovery (not the final level attained) and as 

 the speed is variable the only satisfactory procedure is to 

 assume such values of K ^ and K ^ as cause the closest 

 approximation to the observed speed of recovery. When 

 these values have been found the value of S can readily 

 be calculated. The results of these calculations are plot- 

 ted in Fig. 43. 



In this figure the ordinates give the values of + 10 : 

 these must be multiplied by 6.75 to obtain the values of S. 

 In all curves the value of 8 at the start is 2.7 (the value of 



