348 EEPOET— 1886. 



might be expected tliat in extremely dilute solutions they should coincide. I have ^ 

 shown ' that such a relation does not hold either for aqueous or alcoholic solutions. 

 Bouty - who found complete correspondence between these two quantities, was 

 misled by a coincidence in calculating his results, as Kohbausch has shown.' 



As all known cases can therefore be explained without assuming a connection 

 between internal friction and conductivity, this theory, which serves only to com- 

 plicate matters, must be abandoned. 



As a final proof of the justice of the above conclusion I made a cell like an 

 ordinary Daniell, but introduced gelatine into the solutions of zinc sulphate and 

 copper sulphate. The resistance was 1-5 ohm, while that of a similar Daniell's cell 

 was 1"3 ohm. But the resistance of the cell containing gelatine gradually increased 

 after four days, owing to bubbles being deposited in the gelatine near the zinc and 

 the copper,^ 



Sur la Polarisation des Electrodes et sur la Conductibilite des Liqiiides. 

 Par M. E. Booty.''' Abstract by Oliver Lodge. 



The author first describes Lippmann's method of measuring the resistance of 

 electrolytes, viz. by tapping olf and measuring the fall of potential between two points 

 of the liquid contained in a cylindrical tube, and comparing this with the fall in a 

 known length of wire included in the same battery circuit as the liquid. He 

 proceeds to use it also for determining the polarisation of either electrode, by 

 measuring the potential difference between one of the main electrodes supplying 

 current to the liquid and one of the tapping electrodes ; using the obvious relation 



e=rC +p 



in order to find _p, the polarisation. 



AVith platinum electrodes and acidulated water he thus reckons that with a 

 current of average intensity about 8 x 10"* amperes per square centimetre, the 

 polarisation of the electrode rises as follows : — 



He then applies a slightly stronger current, but as it is very variable T do not 

 see that the numerical results obtained are very useful. However, the idea is that 

 the polarisation of the cathode attains a maximum and begins even to diminish, 

 while that of the anode goes on increasing. 



He then measures the resistance of acid water in a long siphon tube, and con- 

 siders that it is independent of current intensity, and asserts, 'A liquid has only a 

 single way of conducting electricity, whatever may be going on at the electrodes. The 

 expressions '^metallic conductivity " and " electrolytic conductivity" ought to disappear 

 from science.' 



Electrolysis of Mixtuees. 

 A number of mixed salts are tried, one of them being always a salt of copper. 

 Results are given for the electrolysis with copper electrodes of a mixture of sulphate 

 of copper and sulphate of zinc, saturated in the cold, and are analysed thus: ' For 

 current intensities from 5 to 12 ten-thousandths of an ampere per square centimetre 

 the polarisation of the anode is constant and equal to •0088 volt ; but that of the 

 cathode varies enormously. For an intensity 29 (ten-thousandths of an ampere as 

 before) it is already ^02 volt ; it increases slowly with the current and is sensibly 



' Bihang till K. V. Aliad. Handl. viii. No. 13, p. 45 (1884). 



2 Comjd. Rend. February 11, 1884. 



' Gottinger N^achricMen, 1885, p. 86. 



* For remarks on this paper see Prof. Kohkausch's letter on page 343. 



' Journal de Physiqve, 1882, 2e serie, t. i. p. 346. 



