ON ELECTROLYTIC CONDUCTIVITY IN CONCENTRATED SOLUTIONS. 251 



Discussion of Results. 



For a number of electrolytes sufficient data are not available. Sufficiently con- 

 centrated solutions are not attainable for sparingly soluble salts such as Ba(N0 3 ) 2 , 

 KClOg, LiC0 3 , etc., at least not for a temperature so low as 18° C. In other cases 

 the deficiency of data is due to the fact that the concentrations were originally ex- 

 pressed in percentages. Thus for HC1 there are determinations for 5 per cent., 10 per 

 cent., 20 per cent., 30 per cent., and 40 per cent., but the corresponding equivalent 

 concentrations are 1*405, 2*877, 6'034, 9'482. 



Now the range within which equation (1) applies to HN0 3 is in equivalents per litre 

 1"017 to 5"873, and within this range there are only two points for HC1, so that further 

 determinations are required to settle the question. Similar remarks apply to the data 

 for NH 4 N0 3 , Ca(N0 3 ) 2 , and NaC 2 H 3 2 . 



If equation ( 1 ) applies at all to solutions of weak electrolytes such as the organic 

 acids and bases, the range of applicability is certainly small. Here also further data are 

 required. 



Data for forty-nine electrolytes are given in Table A. These include all the salts, 

 strong acids, and strong bases for which sufficient data are given by Kohlrausch and 

 Holborn. 



ZnCl 2 and CdCl 2 stand out as marked exceptions. They are inserted along 

 with CdBr 2 and Cdl 2 , in order to draw attention to the remarkable transition from 

 CdCL 2 , which is a decided exception through CdBr 2 with a very slightly curved graph, 

 to Cdl 2 which shows a perfect agreement between the observed and the calculated 

 values for concentrations between 0'934 and 3 "241 normal. 



For the remaining 46 electrolytes the differences between the observed and the 

 calculated values for A M are given in column IX. Of these 185 differences, only 16 

 exceed 1 per cent., and none exceed 2*1 per cent. Of the 16 differences which exceed 

 1 per cent., 5 belong to Na 2 S, and these five moreover include the only differences 

 which exceed 17 per cent. 



It is not easy to fix a criterion by which the applicability of equation (l) can be 

 judged, or to say how close the agreement ought to be, for it is difficult to come to a 

 definite conclusion as to the limits of error of the original determinations. Kohlrausch 

 and Maltby, in discussing the errors affecting such determinations, make the following 

 statement : " Immerhin kann man ziemlich sicher schliessen dass Fehler von 1 percent, 

 nicht selten vorkommen, was auch von vornherein wahrscheinlich wird sobald man die 

 Fehlerquellen betrachtet." They also suggest a comparison between the results obtained 

 by different observers as one means of throwing light on the question. 



Now for K 2 S0 4 , Na 2 S0 4 , MgS0 4 , and (NH 4 ) 2 S0 4 two sets of determinations are 

 given by Kohlrausch and Holborn, the one set by Kohlrausch and the other 

 by Klein. 



In the case of the first three salts the number of the respective determinations is 



