CHEMISTRY: E. W. WASHBURN 
573 
which the values of shall approach constancy must obviously be 
rejected if we expect to obtain reliable values for Ao and K^. 
In order to avoid the errors involved in what may be called the ' arbi- 
trary function' method of extrapolating, and also in order to avoid the 
uncertainties involved in attempting a direct graphical extrapolation, 
the following method was devised. It rests only upon the following 
two assumptions: (1) That as C decreases, the value of the mass-action 
expression also decreases and gradually approaches a constant, 
FIG. 2 
Kq, at extreme dilutions; and (2) that when the value of once begins 
to approach a constant value, it will not thereafter, that is in more 
dilute solutions, exhibit any erratic behavior such as a rapid rise as the 
concentration decreases, or a sudden fall under the same conditions. 
In other words, it is assumed that those influences which cause a strong 
electrolyte to deviate from the Mass-Action Law gradually and steadily 
become smaller and smaller and finally disappear at high dilutions. 
