190 REPORT—1890. 
conduction without chemical decomposition ; and it may be expressed by 
the formula 
NV Kes 
where W is the weight of electrolyte decomposed by the passage of the 
quantity E of electricity, and K a constant depending on the nature of 
the electrolyte. 
I have worded the statement of this proposition in a carefully 
guarded manner ; it certainly holds for a very large number of electro- 
lytes, possibly for all. The proposition has been gradually evolved as the 
result of a large number of observations. Faraday (Exp. Res. ser. 8, 
§ 970, 984, 1834) allowed a slight amount of conduction without chemical 
decomposition ; and since that time the question has been much dis- 
cussed, and the causes of the apparent metallic conduction traced. An 
account of the discussion is given in Wiedemann, vol. 2, p. 488, which is 
summed up as follows: ‘According to all these experiments we must 
now accept that if once the conduction of currents through electrolytes 
is associated with their simultaneous decomposition, then, besides this 
electrolytic conduction, which follows strictly the electrolytic [ Faraday’s | 
law, no second metallic conduction of apart of the electricity takes place 
therein.’ Von Helmholtz in Part III. of his ‘ Thermodynamics of Chemical 
Processes’ (Phys. Soc. Translation, p. 79) says: ‘If the two electrodes 
of a voltameter be charged and maintained at different potentials, electric 
forces corresponding to the slope of potential act within the fluid, driving 
+ E to the cathode, — Eto theanode. This movement of electricity never 
takes place, so far as we know, without a simultaneous motion of the ions 
of the electrolyte to which the + E and — E set in motion are attached’ ; 
and in the next page, ‘I have myself succeeded in following out the pro- 
portionality between the electromotive force and the amount of condensed 
charge . . . . down to electromotive forces of 0:0001 Daniell.’ 
Von Helmholtz also expressed the same view in the Faraday Lecture, in 
which he announced that with an air-free cell therein described he had 
detected the polarisation produced during a few seconds by a current 
which would only decompose a milligramme of water in a century; and 
he went on to say: ‘ But even if the appearance of galvanic polarisation 
should not be acknowledged by opponents as a sufficient indication of 
previous decomposition, it is not difficult at present to reduce the indica- 
tions of a good galvanometer to absolute measures and to calculate the 
amount of decomposition which ought to be expected according to 
Faraday’s law, and to verify that in all the cases in which no products of 
electrolysis can be discovered their amount is too small for chemical 
analysis.’ 
Bouty (quoted by Lodge, ‘ B.A. Report,’ 1886, p. 348), referring in par- 
ticular to acidulated water, 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.’ 
Experiments on the decomposition produced in acidulated water by 
the induction of electrostatic charges are described by Wiedemann (2, § 
544) and by Ostwald and Nernst (‘ Electrician,’ 23, p. 300, 1889), who 
observed a bubble of hydrogen which would correspond to the decom- 
position of 4 x 107!° gramme of water. Eouvet (‘C. R.’ 87, p. 1068) 
has found that the quantity of electricity necessary for decomposing a 
