1904.] Theory of Amphoteric Electrolytes. 



165 



The values of ^ calculated from the theory agree very well with 

 those found by Ostwald, somewhat less well with those of Winkelblech. 

 The most interesting point about the " constant " k is that there is a 

 minimum in both the calculated and experimental values at v = 64. 



The experimental data for meta-amino-benzoic acid are not so 

 satisfactory as those for the isomeric acids just considered. Ostwald 

 and Winkelblech found, widely divergent values of the conductivity. 

 Since in the following calculations use is made of Winkelblech's 

 constants, the comparison of conductivities can only be effected with 

 his numbers. The value of Jc b /K found by the hydrolysis method is in 

 round numbers 1100. This involves an addition of over 30 per cent, 

 to Jc at v = 1000 in order to arrive at an approximate value of k ai 

 which in this case comes to be 1*4 x 10~ 5 . 



m-Amino-benzoic Acid, 1 : 3-NH 2 .C 6 H 4 .CbOH. 

 VK = 1100, h a = 1-4 x 10- 5 , ^„H + ,XOH-= 355, /^HX+XOH" = 66. 



V. 



a. 



d. 



jx calc. 



M(W.). 



Jc calc. 



h (W.). 



64 



10 '9 x 10" 5 



163 -0 x 10~ 5 



9-36 



9-36 



11 -1 



11 -2 



128 



10 -6 



79 -2 



11 -51 



11 -72 



8 -5 



8-8 



256 



9-99 



36 -2 



15 -20 



16-04 



7-5 



8 -4 



512 



9-07 



16 -5 



22 -06 



23 -04 



8-0 



9-1 



1024 



7 73 



6-88 



32 -77 



! 35 -24 



9-2 



10 -7 



Here it will be noted that the agreement is by no means so close as 

 in the previous instances. This is probably connected with the fact 

 that the meta-acicl rapidly oxidises in contact with platinum electrodes, 

 and assumes a dark brown colour. The effect of this oxidation would 

 he most apparent in the dilute solutions. Notwithstanding the want 

 of exact accordance, the run of the constants is similar, both the values 

 calculated from the theory and the values given by Winkelblech 

 exhibiting a minimum at v = 256. 



These instances exhaust the data in Winkelblech's paper for which 

 an exact comparison of the theory with experiment is possible. They 

 cover a range for k^/K of 110 — 1100, and in each case the peculiarities 

 •of the " constants " are faithfully reproduced by the theory. An 

 experimental investigation of some other substances to which the 

 theory is applicable is at present in progress, and I hope in a future 

 paper to communicate the results obtained. 



VOL. LXXIII. 



N 



