258 On Establishment of Difference of Potential, c. [June 21, 



either of the two former experiments, it being wet on the surface 

 with, rain falling during a portion of the time, and dry underneath. 



Curve 6 in fig. 3 appears to show by its form the effect of this state 

 of the soil, the fall of potential from B to D being approximately 

 indicated by a straight line. That is to say that the current flow was 

 practically entirely confined to the surface layer. The curve is 

 deduced from the results of experiments shown in Table III for a 

 charging pressure of 550 volts. 



Table III. Experiment of 22nd May, 1804. 



In order to obtain a direct indication of the statical P.D. between 

 weights A and B, the voltmeter which had been used for recording 



