V^/ 



THE 



AMERICAN JOURNAL OF SCIENCE 



[THIRD SERIES.! 



Art. XL — The Use of Cupric Nitrate in the Voltameter^ 

 and the Electro-Chemical Equivalent of Copper ; by Fred- 

 erick E. Beach. 



[Contributions from the Sloane Physical Laboratory of Yale College.] 



Among the voltameters in common use the silver voltameter 

 gives results of a very high degree of accuracy, but is not 

 conveniently used except for comparatively small currents. 

 On the other hand the copper voltameter from the cheapness 

 of materials and facility of manipulation finds convenient 

 employment in the laboratory. As ordinarily used with the 

 sulphate of copper, it is subject to certain irregularities due to 

 the attack of the copper by the solution under some condi- 

 tions, and the oxidation of the metal in others. For these 

 reasons as well as for the fact that excellent deposits of metal 

 are obtained from the nitrate of copper, even with great cur- 

 rent densities, it seemed probable that this salt could be suc- 

 cessfully used in the voltameter. The object of this paper is 

 to show that cupric nitrate has some marked advantages over 

 the sulphate. For purposes of comparison the results and 

 conclusions of different experimenters will be passed in review. 



Gore* expresses the opinion that two independent forces act 

 in the solution, one chemical the other electro-chemical. The 

 action of the former is assisted by a rise of temperature. The 

 loss of the anode is greater than the gain of the cathode, but 

 the chemical corrosion of the anode is less than that of a sepa- 



* Nature. March 16, 1882. 



Am. Jour. Scl— Third Series, Vol. XLYI, No. 272.— August, 1893. 

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