460 Prof. 0. Lodge on the Controversy 



NH 4 Cl solution with the same concentration ratio 10 : 1. In 

 this case 



69 inAK 

 r= 7^ =1*045. 



66 



SO lr( '114 r.rrr, ,, 



E= 2^045 ='° 557v0lt ' 



and Nernst gives it as observed at -0546. 



Once more, take a cell filled with KOH solution 10 : 1 ; 



182 9-7* 



r=-^=2 76, 

 therefore E = ^= '0303 volt, 



O* ( 



and it is observed at '0348. 



A cell of LiCl gives another example, strength as before 

 decinormal and centinormal, that is'l gramme equivalent per 

 litre on one side, and 01 ditto on the other : 



r» % =1-925. 

 36 



E=^4= -0390 volt, 

 2-925 



observed at *0354. 



Here more old-fashioned values for the migration numbers 

 give a result more nearly agreeing with observation. 



Another cell where the agreement is not so close is one of 

 caustic soda, NaOH. Nernst quotes one with strengths '235 

 gramme equivalents per litre on one side, and '030 on the other, 

 so that the concentration ratio is 7*83, while the migration 



*• ' 182 A.l\K 

 ratio is -rr- =4*05. 



45 

 The observed E.M.F. was '0178 volt, whereas the calcu- 

 lated is 



'i^log 7-83= -0201 volt. 



At least that is what I get, but as in several other cases the 

 column of "calculated" given by Nernst does not contain the 

 same numbers as those here obtained. Sometimes they agree 

 with observations better, but sometimes worse. 



These agreements, though not perfect, are clearly far and 

 away beyond anything attributable to chance, and they 

 practically substantiate the essential features of Nernst's theory, 

 a theory which seems to me to rank high among rational 



