CHEMISTRY: E. W. WASHBURN 
575 
a rejected series. The two bounding curves above and below the heavy 
curve represent the shift in the position of this ' best' curve which would 
be produced by a total error of 0.02%; for instance, an error of 0.01% 
in the concentration in combination with an error of 0.005° in the 
temperature of the solution. Since most of the observed points fall 
within the limits set by these two curves, it is evident that the agree- 
ment among them is even better than could be expected, considering all 
of the difficulties and chances of error involved in the work. A detailed 
account of Dr. Weiland's work will be published later. 
With the aid of the conductivity data for potassium chloride presented 
above, it becomes possible to establish two general laws with respect to 
the behavior of strong electrolytes in dilute solutions. These laws may 
be stated as follows : 
1. In sufficiently dilute solution (i.e., for all practical purposes below 
0.0001 normal) all uni-univalent salts of strong acids and bases obey the 
Mass-Action Law, and all of them have the same ionization constant, 
2. In sufficiently dilute solutions the values of the mass-action 
expression for all such salts are identical, the identity persisting up to 
higher concentrations the more nearly the salts under comparison 
resemble each other, and in any case persisting within the experimental 
error up to 0.0002 normal for all salts which have been accurately 
measured at these concentrations. In the case of two salts, such as 
potassium chloride and potassium bromide, for example, which resemble 
each other very closely, this identity persists up as high as 0.005 normal. 
With the aid of the second of these laws it is now possible to derive 
a general rule by means of which the Ao value for any uni-univalent 
salt can be accurately obtained from the value of the equivalent con- 
ductance of that salt at a single concentration, say 0.0001 normal. 
This rule is deduced as follows : 
The second law stated above is expressed mathematically by the 
equation, 
where the value for is independent of the nature of the salt, 
and can therefore be read off from the curve in figure 3 (or pref- 
erably from a similar curve for a salt resembling as closely as pos- 
sible the one under examination). Solving this expression we find 
(with sufficient accuracy), Ao = ( 1 -f — ], an expression by means 
AoiAo - A) 
