372 Mr. G. Gore. Effects of different Positive Metals [June 21, 



The following are the proportions of iodine which were required 

 to change the potentials, when the astatic galvanometer was 

 employed : — 



Table VIII. 



Zn + Pt. Between 1 part in 3,100,000 and 3,521,970 

 Mg + Pt. „ 1 „ 577,711 „ 643,153 

 Cd + Pt. „ 1 „ 200,431 „ 224,637 



Table IX.— Mg + Pt + Bromine in 13,950 grains of Water at 12° C. 



Grrains. 



Volts. 



Grrains. 



Volts. 



0-000045 

 -0000405 

 -000036 



1-5757 

 1-5600 

 )> 



-00003375 

 0-0000225 

 water 



1 -5600 



The smallest proportion of bromine required to change the 

 balance lay between 1 part in 310,000,000 and 344,444,444 parts of 

 water. 



The minimum proportion necessary to disturb the potential of a 

 zinc-platinum couple in water has been already given (' Roy. Soc. 

 Proc.,' May 31, 1888), and was between 1 part in 77,500,000 and 

 84,545,000. 



Table X.— Cd + Pt + Bromine in 465 grains of Water at 19° C. 



Grrains. 



Volts. 



Grrains. 



Volts. 



Grrains. 



Volts. 



20-1 



1 -8881 



13 26 



1-824 



6-42 



1 -5163 



18-39 



1 -8709 



11-55 



1-5492 



4-71 



1-589 



16-68 



1 -8538 



9-84 



1 -5349 



3-0 



1-543 



14-97 



1 -8307 



8 13 









The strongest solution was a saturated one. 



