Physics. 239 



The following are the chief facts established by this research : 

 That a species of electric "resistance," distinct from that of polar- 

 ization and of ordinary conduction-resistance, varying greatly in 

 amount in different cases, exists at the surfaces of mutual contact 

 of metals and liquids in electrolytic and voltaic cells. That this 

 "resistance" varies largely in amount with different metals in the 

 same solution, and with the same metals in different solutions, in 

 dilute solutions of mineral acids of different strengths, or of differ- 

 ent temperatures; and is usually small with easily corrodible 

 metals which form quickly soluble salts, and large with those 

 which are not corroded; and is disguised in the case of those 

 which by corrosion form insoluble salts. 



The results of the experiments also show that the same voltaic 

 current was " resisted " in different "degrees by every diffei-ent 

 metal when employed as an anode, and when used as a cathode; 

 also by the same metal when used as an anode and cathode 

 respectively ; and that the proportions of such " resistance " at 

 an anode and cathode of the same metal, varied with every differ- 

 ent metal in every different electrolyte (and strength of electrolyte), 

 and at every different temperature ; and that the resistance at 

 the anode was usually smaller than that at the cathode ; in some 

 cases, however, where a film was formed upon the anode, an ap- 

 parently reverse effect occurred ; that a current from a given posi- 

 tive plate of a voltaic cell was differently resisted by every differ- 

 ent metal used as a negative plate in that cell ; and that by rise 

 of temperature " transfer-resistance " was usually and considera- 

 bly reduced. 



They further show that this species of " resistance " was largely 

 reduced by increasing the strength of current; and was thus con- 

 spicuously distinguished from ordinary conduction-resistance of 

 the electrolyte. In consequence of this effect, " transfer-resist- 

 ance " was greatly influenced by every circumstance which altered 

 the ordinary resistance, and thereby the strength of current. The 

 usual effect of diminishing the density of current alone, by enlarg- 

 ing both the electi*odes and keeping the strength constant, was to 

 diminish the " transfer-resistance ;" and of enlarging one only, 

 was to diminish it at that electrode and increase it at the other, 

 the effect being greatest at the altered electrode ; but the influence 

 of density was very much smaller than that of strength of current. 

 The current was usually less " resisted," and larger with a small 

 positive plate and a large negative one, than with those sizes 

 reversed. Alterations of size or kind of metal at one plate of an 

 electrolytic or voltaic cell affected the " transfer-resistance " at the 

 other, by altering the strength and density of the current. 



" Transfer-resistance," therefore, appears to vary, not only with 

 every physical and chemical change in the metals and liquids, but 

 also with every alteration in the current. Such "resistance" 

 throws light upon the relative functions of the positive and 

 negative plates of voltaic cells, and illustrates the comparatively 

 small influence of the negative one in producing strength of cur- 



