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 LXIX. Intelligence and Miscellaneous Articles. 



VERIFICATION OF THE LAW OF ELECTROLYSIS WHEN EXTERNAL 

 WORK IS PERFORMED BY THE GALVANIC CURRENT. BY M. J. 

 L. SORET. 



TN order to explain, conformably with the mechanical theory of 

 -*■ heat, the production by an electric current of effects external to the 

 circuit which it traverses, such, for instance, as the performance of 

 mechanical work or the generation of induced currents, recourse has 

 been had to an hypothesis proposed by Helmholtz, Scoresby and Joule, 

 Clausius, and other physicists. According to this hypothesis, the 

 law of electrolytic action is regarded as still holding good for this 

 special case. In order to supplement previous investigations, I un- 

 dertook the verification of this point by comparing the amount of 

 chemical action with the mean intensities of currents, usually dis- 

 continuous, by which external work was performed. 



In order to produce powerful external effects, I have employed for 

 the most part a Ruhmkorff's coil, but I found it needful in most 

 cases to substitute a contact-breaker formed of a toothed wheel and 

 platinum spring for the ordinary contact-breaker of this apparatus. 

 By this means I obtained a much more rapid succession of currents, 

 and at the same time greater stability in the needle of the sine-com- 

 pass by which the mean intensity of the current was measured. 



After a great number of experiments performed for the purpose of 

 assuring myself of the exactitude of the method I was employing, I 

 arrived at the following results, which confirm the law of electrolysis 

 for these conditions. 



In a circuit of great resistance, containing a Daniell's battery, the 

 sine-compass, a voltameter charged with sulphate of copper, and the 

 inducing coil of the Ruhmkorff's apparatus, the weight of copper 

 deposited in the voltameter was found to be always proportional to 

 the mean intensity of the current, whether the current was conti- 

 nuous (that is to say, when the contact-breaker of the Ruhmkorff's 

 apparatus was excluded from the circuit, in which case no external 

 action took place) or whether it was discontinuous (that is to say, 

 when the contact-breaker was put in action, in which case an ex- 

 ternal action was set up, though this was certainly of small import- 

 ance relatively to the total work performed by the current). 



A similar result was obtained with a circuit of small resistance, 

 consisting only of the Ruhmkorff's apparatus, the compass, and a 

 single Daniell's cell in which a plate of platinum was substituted for 

 the. copper. The chemical action was measured by the quantity of 

 copper deposited upon the platinum plate. With this disposition of 

 the apparatus, the proportion of external work when the contact- 

 breaker was put in action was considerable. 



Under the same conditions, the quantity of electro-positive metal 

 (cadmium) which is dissolved in the battery is also proportional to 

 the intensity of the current. This determination cannot be made 

 with as much accuracy as that of the weight of copper deposited, but 

 the mean result of the experiments agrees with the law of electro- 

 lysis. — Comptes Kendus, vol. lix. p. 485 (September 12, 1864). 



