398 Table 464 



COMPOSITION AND ELECTROMOTIVE FORCE OF VOLTAIC CELLS 



The electromotive forces given in this table approximately represent what may be expected fron 

 cell in good working order, but, with the exception of the standard cells, all of them are subject to c< 

 siderable variation. 



* Depolarizer: Manganese peroxide with powdered carbon. ** Depolarizer; CuO. *** Depolarizer: Silver chloride. 



dE 

 t F. Streintz gives the following value of the temperature variation -j— at different stages of charge: 



E. M. F. 

 dE/dt X io« 



1.9223 

 140 



1.9828 

 228 



2.0031 

 335 



dt 



2.0084 



285 



2.0105 

 255 



Dolezalek gives the following relation between E. M. F. and acid concentration: 

 Per cent H5SO4 64.5 52.2 35-3 21.4 

 E. M. F., o°C 2.37 2.25 2.10 2.00 



Smithsonian Tables 



2.0779 

 130 



5-2 



1.89 



2.2070 

 73 



