252 Dr. Gr. Gore on "Resistance" at the Surfaces 



As the liquid was not stirred, the " surface-resistance " 

 at each of the two plates included not only what I have termed 

 " transfer resistance/' but also any opposing influence due to 

 polarization developed by the current. As, however, the 

 reverse current, produced by first connecting the gold and 

 nickel plates with the battery for a time equalling that of 

 duration of the experiment, and then instantly switching 

 them to a galvanometer, was less than one hundredth the 

 strength of half the total current employed in ascertaining 

 the inequality of " resistance," the opposing effect due to 

 polarization must have been exceedingly small, and was equal 

 at the two plates. I have already shown in a large variety 

 and number of cases, described in an extensive research com- 

 municated to the Royal Society, March 2, 1885, that the 

 " resistance" still exists, and varies greatly in amount in 

 different cases, when polarization is nearly or entirely pre- 

 vented by employing and rapidly stirring a suitable electrolyte. 

 It may also be remarked that the amount of " resistance " is 

 not directly proportional to that of polarization ; for whilst 

 the opposing force of the latter increases with increased 

 strength of current, "transfer-resistance" decreases. 



A second solution, composed of 7'0 grammes of potassic 

 chloride, '05 gramme of potassic cyanide (of 92 c l per cent.), 

 and 80 cubic centim. of water at 8° C, was tested with plates 

 of gold and iron in a similar manner. The plates were each 

 1*0 x 1*0 centim,, about 9'0 centim. asunder, and not varnished 

 on their backs ; the gold was very faintly positive, and this 

 disappeared on stirring the liquid. The total strength of cur- 

 rent employed was *0014 ampere, or *0007 to each plate. The 

 middle plate was of iron. With the two metals as anodes, 

 the iron offered 1230 ohms less, and as cathodes 26*0 ohms 

 less, "resistance" than the gold. 



And with plates of nickel and copper 1*0 x 1*0 centim., 

 9*0 centim. apart, and varnished on their backs, in a third 

 solution, composed of 1*89 gramme of potassic bromide dis- 

 solved in 100 cubic centim. of water at 8° C, the potentials 

 were equal. The strength of current employed was '00058 

 ampere, or -00029 to each metal. The middle plate was of 

 copper. With the two metals as anodes the nickel offered 

 650 ohms greater, and as cathodes 210 ohms less, than the 

 copper. 



We know that the contact of two pieces of the same metal 

 with an electrolyte of uniform temperature produces no dif- 

 ference of potential. I therefore took two electrodes of sheet 

 platinum, varnished on their backs, one being 1*0 x 1*0 cen- 

 tim., and the other 2*0 x 5*0 centim. and 8*0 centim. apart, 



