108 



Mr Laby, A string electrometer. 



Properties of a String Electrometer. 



The purpose of the tests was to find how : 



(1) the sensitiveness, 



(2) the oscillograph powers of the electrometer depended on 



(a) distance of the plates apart, 

 (6) their potential difference, 

 (c) the tension on the fibre. 



Potential difference between plates in volts 

 Fig. 2. 



Plates far apart (1"1 cm.). The plates were set far apart 

 (compared to the distance moved through by the fibre) and then 



