254 On "Resistance" at the Surface of Electrodes. 



With the gold and nickel plates in the solution of potassic 

 cyanide at 8° 0., and a strength of current ='00029 ampere, 

 the " resistances " were : — 



As Anode. As Cathode. 



Grold . . . 114 ohms. 1044 ohms. 

 Nickel ... 143 „ 801 „ 



With the gold and iron in the mixture of potassic chloride 

 and cyanide at 8° C, and a strength of current = *0007 ampere, 

 the " resistances " were : — 



As Anode. As Cathode. 



Gold . . . 1136 ohms. 768 ohms. 

 Iron ... 56 „ 360 „ 



And with nickel and copper in the solution of potassic 

 bromide at 8° C, and a current of '00029 ampere, the 

 " resistances " were : — 



As Anode. As Cathode. 



Nickel . . . 639 ohms. 1565 ohms. 

 Copper ... 130 „ 1565 „ 



The results obtained by this method agree substantially 

 with those obtained by the previous one ; there are, however, 

 some considerable discrepancies in the amounts. It need 

 hardly be remarked that in such experiments it is very diffi- 

 cult to obtain perfectly concordant quantitative results by two 

 such different methods, and that it would not be reasonable to 

 expect them. The results uniformly confirm the conclusion 

 that " surface-resistance " may exist independently of all 

 difference of electric potential. 



Equality of voltaic potential, attended by more or less 

 difference of " surface-resistance/'' may be obtained by a 

 variety of arrangements ; and a large number of additional 

 instances might be selected in which the potentials are equal 

 whilst the " resistances " are unequal. The ones chosen were 

 preferred because they were convenient and comparatively 

 manageable. Cases of equality of " resistance " accompany- 

 ing difference of potential might probably also be found. 



Is the phenomenon I have detected really of the nature of 

 ordinary electric conduction-resistance ? If it is, its charac- 

 ters will agree with the most essential ones of that influence. 

 It agrees in several important points with ordinary conduction- 

 resistance : first, it is not able to produce a current ; second, 

 it is usually small with those liquids in which ordinary resist- 

 ance is small ; and, third, it is considerably reduced in liquids 

 by rise of temperature (see " Relations of Surface-resistance 

 at Electrodes," Phil. Mag. vol. xxi., Feb. 1886). It differs, 



