OF ZINC, CADMIUM, LEAD, COPPER, AND LITHIUM 



45 



TABLE 8. 



Thus for cups 1-3 there are four results for A?r to be taken directly 

 from the table, and three more by subtracting the values for the cups 3-4 

 from those for the cups 1-4. There are also four values for the value of 

 TT for 1-3 at o two given in the table, and two obtained by subtracting 

 the values for 3-4 from those for 1-4. These are recorded below in 

 table 9, in order to give some idea of the accuracy of the work. 



TABLE 9. 

 [Cell Mi-M3 (or Ni-N3)]. 



Thus this cell with its amalgams containing about 0.0913 and o.ioo 

 per cent of zinc, respectively, gave a potential of 0.024237 volt 0.0000008 



at o, and changed its potential by 0.002799 vo ^ 0.000001 on being 



raised to 29.96. The value for 



ATT 



is therefore 0.003855 instead of the 



value 0.00366 shown by the increase in pressure of a nearly perfect gas 

 the standard upon which our temperature scale rests. 



In the same way, seven results for cell 1-4 give on the average 

 ATT= 0.004332 volt 0.000001 ; and for cell 3-4, seven similar results give 

 A7r=o.ooi54i volt 0.000001. From these results, as well as from the 

 figures given in the table for the other combinations, the corresponding 

 values for the temperature coefficients may be readily computed, it being 

 borne in mind that wherever cup 2 is concerned, the cells M and N must 



