OF ZINC, CADMIUM, LEAD, COPPER, AND LITHIUM 



ELECTROMOTIVE FORCE BETWEEN ZINC AMALGAMS. 



The first series of results with zinc amalgams, although not of sufficient 

 accuracy to yield trustworthy temperature coefficients, are worth recording 

 as a corroboration of the results obtained during the previous investigation 

 of Richards and Forbes. 



In the first case the most concentrated amalgam contained 0.90 per cent 

 of zinc. It was placed undiluted in the first cup of the multiple cell 

 described in the foregoing paper, 35 was diluted with mercury in the third 

 and fourth cups, and finally the parent amalgam was again put undiluted 

 in the remaining second cup, in order to be sure that no change had taken 

 place in the amalgam during the filling of the cell, and also that the 

 amalgam had been in the first place thoroughly mixed. This precaution 

 was usually taken in the subsequent work also, but only in one case, 

 mentioned later, was a difference greater than 0.000002 volt ever found 

 between the first and the last portions of amalgam. As is shown below, 

 the maximum difference in the present case was only one millionth of one 

 volt. 



In addition to this series of measurements, another was made upon three 

 more dilute amalgams, in order to show the increasingly near approach 

 of the potential to the gas law. Table 6 gives both series of measure- 

 ments at 30. The details of dilution, etc., need not be given as regards 

 these preliminary results. The theoretical potential given below is calcu- 

 lated according to the simple concentration equation. 



TABLE 6. Preliminary Electrical Measurement of Zinc Amalgams. 



This monograph, p. 15. 



