ON ELECTROLYSIS IN ITS PHTSICAL AND CHEMICAL BEARINGS. 357 



On Mechanical and Thermal Effects accompanying Electrolysis. By 

 M. BouTT. Brief Abstract by Oliver Lodge. 



A series of short memoirs have been published by M. Bouty in the ' Journal de 

 Physique ' on a branch of the subject not very immediately connected with that 

 which at present concerns us. I had occasion to refer to part of them in a commu- 

 nication on the seat of E.M.F. in the voltaic pUe. (See ' B.A. Report,' 1884, pp. 492 

 and 513-518, or ' Phil. Mag.' vol. xix. 1885, pp. 189 and 343 to 350.) 



The references to them are as follows: — 



1. On some mechanical and thermal effects accompanying electrolysis (' Journ. de 

 Phys.' 1879, t. viii. pp. 289 and 341). 



2. Thermo-electric and electro-thermic phenomena at contact of metal and liquid 

 (1880, t. ix. p. 306). 



3. On the contraction of galvanic deposits, and its relation loith the Peltier pheno- 

 menon (1881, t. X.) 



In the first of these papers, metals are deposited on silvered thermometer 

 bulbs and the mechanical compression caused by the different deposits studied ; 

 Wertheim's results in elasticity being applied to them. 



The effect of heat on such metallised thermometers is also discussed. 



Metallised thermometers are then used as electrodes to examine the changes of 

 temperature which occur while various ions are being liberated. During the elec- 

 trolysis of CUSO4 or ZnSO^ the anode is slightly warmed, the cathode slightly 

 cooled ; inverting the current cools the new cathode distinctly. Electrolysiog dilute 

 H.,S04 with platinum coated thermometers, the anode is quite warm, the cathode 

 scarcely at all. Tbis is the permanent eflect. Inverting the current cools the old 

 anode, sometimes \ degree below the temperature of the surrounding liquid. _ The 

 effect can be repeated seven or eight times, although with decreasing intensity, if 

 one takes care to stir the liquid between the inversions. 



Replacing H.,S04 by HCl, the permanent effect is very small, but both poles 

 heat strongly at 'each inversion. With PtCl4 one observes at each inversion a 

 coolmg of the old anode and a heating of the old cathode. In every ease examined, 

 anode is hotter than cathode in the permanent state. 



In the second paper, metal-liquid junctions are warmed and cooled alternately 

 so as to give thermo-electric currents, the E.M.F. of several circuits being mea- 

 sured. An attempt is then made to measure absolutely the coefficient of the 

 Peltier effect at these junctions when a current passes ; a method suggested by Max- 

 well (' El. Electricity^' p. 146) being used. The result is that the author believes 

 the effects to be purely physical, without known relation to the heats of combination 

 or the latent heats of solution, but connected exactly with the thermo-electric forces 

 of couples corresponding. The thermo-electric laws of Sir W. Thonison are believed 

 to apply without modification. Chemical effects are regarded as disturbances pro- 

 ducing parasitic heats. 



In the third paper, the author reconsiders the contraction of galvanic deposits ui 

 the light of the Peltier effect, and comes to the simple and satisfactory conclusion 

 that the two phenomena are immediately connected. Each envelope being deposited 

 at a rather higher temperature than it is able afterwards to maintain, a state of com- 

 pression naturally results. This view he sustains by experiment. 



Eecherches sur la Conductihilite galvanique des Electrolytes {152 pages). 

 Par SvANTE Aeehenius. Memoire presents a VAcad. des Sciences de 

 Suede le 6 Jidn 1883. Published at Stockholm, Konigl. BoUrycTceriet. 

 Norstedt and Soner. 

 PART I. — On the Conductivity of Extremely Dilute Aqueous Solutions, deter- 

 mined hy means of the Depolariser (63 pages with p)late). Critical 

 Analysis by Oliver Lodge. 



Whatever may have been the importance of the Jirst part of this memoir at the 

 date of its appearance (1883), the publication last October in Wiedemann's/ Annalen ' 



