182 Dr. C. R. A. Wright on the Determination of 



In accordance with the ordinarily received views as to the 

 atomic and molecular constitution of matter, it would seem 

 to result from the fact that the maximum counter E.M.F. 

 set up during electrolysis of water exceeds 3 volts, that the first 

 action of the current is to break up the water (and similarly 

 for other electrolytes) into free atoms of the components, 

 which atoms then rearrange themselves into molecules either 

 as a secondary action or under the condensing action of the 

 electrodes, or both ; whence it would seem that the sum of 

 the heat of condensation of hydrogen atoms to molecules together 

 ivith that of oxygen atoms to molecules exceeds that of the union 

 of the hydrogen and oxygen atoms together to form molecules of 

 liquid loater. 



66. The phenomena connected with " subsequent polari- 

 zation " (§ 58, footnote) are just as readily explained by the 

 theorem as those relating to the counter E.M.F. set up 

 whilst the current is passing. When visible decomposition 

 has taken place for some time, so that the electrodes are sur- 

 rounded respectively with a saturating aura of hydrogen and 

 of oxygen, varying in density from the highest to the lowest 

 possible value, and when, in addition, there are in the vicinity 

 of the electrodes more or less of the " nascent " products of 

 electrolysis, the counter E.M.F. set up during the passage of 

 the current, and therefore representing the polarization at the 

 instant of rupture, is (§ 61) 



« = E I+ [2{(l-n)H}-2(«A)-2(H)]aJ. 



After the lapse of a given interval of time (however small), 

 more or less of the " nascent " products have spontaneously 

 changed into the final products, viz. oxygen and hydrogen, 

 thereby diminishing the value of 2{(1 — n)H}, and conse- 

 quently lessening the value of e, the " polarization." Even 

 after sufficient time has elapsed for the whole of the " nascent 

 products " to have thus transformed themselves, the diffusion 

 of water containing dissolved oxygen to the hydrogen elec- 

 trode from the other, and of water containing dissolved 

 hydrogen from the hydrogen electrode to the other, w r ill still 

 cause, by chemical action, a continual removal of portions of the 

 aura of attracted gas round each electrode, thereby causing a 

 continual increase in the mean value of 2(nA)*, and hence a 

 further diminution in the value of e ; finally the polarization 

 must become 0, when 



{2(n/*) + S(H)} x J = B 1 = l-50 volt. 



* Gladstone and Tribe have shown (Chein.-Soc. Journ. Trans. 1878, 

 p. 806) that hydrogen condensed by surface-attraction upon or occluded 

 by certain solids (e. <j. palladium, platinum, or carbon) exerts a much 



