[300] THE USE OF THE GOOCH CRUCIBLE AS 

 A SILVER VOLTAMETER 1 



FOR the exact measurement of electric currents, no method 

 is more convenient and more free from objections than the 

 determination of the amount of silver deposited from a neutral 

 solution of a silver salt. The sole source of error, especially 

 where weak currents are concerned, arises from the imperfect 

 adhesion of the silver upon the cathode. The latter is gener- 

 ally a platinum crucible, and the silver, except for densities 

 of current not always attainable, is deposited in minute 

 scales and needles, instead of forming a coherent coating. 

 In the subsequent washing and decantations, those par- 

 ticles are readily detached and carried away, and a loss is 

 occasioned which becomes very appreciable when the total 

 deposit does not exceed a few centigrams. A Gooch crucible, 

 with asbestos felting over the holes, would be a far better 

 form of cathode, if it would only hold the solution during 

 electrolysis without leaking. I have attained this very satis- 

 factorily, by replacing the ordinary platinum cap with a glass 

 siphon of the shape indicated in Fig. 1. 



. 1. FIG. 2. 



1 Reprinted from Journal of the American Chemical Society, 12, 300 (1890). 



