110 



The tubes were lirst (ille<l willi an almost .satiu-ated solution of Cu 

 S04. On workiug for two days with this electrolj^te trying many different 

 adjustments it was found that the back or electrolytic E. M. F. was so 

 variable that no reliable results could be secured. The only thing deter- 

 mined positively was that lengthening the distance between the disks 

 in I caused a deflection E, and lengthening that in II produced a deflec- 

 tion "W. 



On filling the tubes with pure distilled water the results were some- 

 what more definite. With the disks li cm. apart the following data 



Tigure 1. 



Dimensions of essential parts of apparatus of FiErure 1. 

 i\^ Glass tubes. I and II. 



Length of each. 10 cm. 



Internal diameter of each, 17 mm. 

 (2) Copper discs, dl, d2, d3, and d4. 



Diameter of each, 10 mm. 



Thickness of each, 1 mm. 



