concerning Voltcis Contact Force. 467 



charged corpuscle is the mobile ingredient; so that superposing 

 a positive charge on a negatively charged atom is not adding 

 something to the corpuscles already there, but is removing the 

 extra negative corpuscle and another as well ; taking the atom 

 down therefore instead of building it up, and leaving a void 

 which automatically fills itself up whenever it gets a chance. 

 It is just possible that some kind of effective transmutation 

 might be effected in an electric spark or arc with different 

 materials on either side of it ; like a substance passing over 

 from one crystalline form to another. 



Whether combination of atoms takes place across any junction 

 when a current passes, appears to be merely a question of 

 relative mobility of corpuscles and atoms. If the atoms are 

 free to move, if it is easier to move an atom across the inter- 

 face than to detach from it a corpuscle, then combination occurs, 

 and the conduction is then necessarily on one side essentially 

 electrolytic ; and at a liquid-liquid junction there may be 

 double atomic freedom and complete electrolysis. But if 

 the corpuscles are more detachable than the atoms, then the 

 conduction is metallic and no alloy is formed. 



But now, pressing further the osmotic pressure view, if the 

 metals can evaporate into a liquid they ought perhaps to be 

 able to evaporate into each other, and so the E.M.F. at a 

 junction ought to be calculable as 



E = EeT( - )log», I 



n 

 where the —, may be taken as the ratio of the metallic densities; 



but what shall we put into the brackets for the ionic velocities ? 

 Not ionic velocities at all, but corpuscular velocities, and these 

 corpuscular velocities may differ by reason of the different 

 viscosity or obstruction offered by each metal ; which again 

 perhaps may be proportional to the density; but the solution 

 can hardly be treated as a weak one, or the gaseous laws as 

 applicable. 



If gaseous laws are applicable to the corpuscles inside 

 metal, the value of this characteristic constant R will be 

 500 or 600 times the value for hydrogen ; but inasmuch as 

 the m, or e the electrochemical equivalent, 'is 1/500 or 

 1/600 of the hydrogen value, the resulting ReT comes out 

 just as usual. 



The viscosity or obstruction offered by metal is probably 

 its electrical resistance; and so the corpuscular velocity in 

 each may be proportional to the conductivity. 



Conductivity in a liquid means greater mobility of the 

 2K2 



