Device for charging Electroscopes, 



359 



This tube remains, on the other hand, in permanent con- 

 nexion with the piece ff, consisting of two coaxial cylinders 

 and moved together with a. When the rod is at the end of 

 its path, a small finger g lightly touches the support of the 

 leaf to be charged. Bv releasing the pressure on b, the 



spring h brings the rod to its original position, simul- 

 taneously connecting / with the brass disk i, and con- 

 sequently with the electroscope-case. The dimensions being 

 chosen consistent with the capacity of the leaf-support, 

 things are easily adjusted so as to produce a convenient 

 deflexion of the leaf with a single push of the button. A 

 good plan is to overcharge the leaf a little and to keep the 

 button down until the system has discharged itself to the 

 desired point, which is readily attained owing to the leak 

 through the ebonite parts of the charging device. 



It is hoped that this device may prove useful not only in 

 the laboratory but also for electroscopes in field-work. 



Petrograd, Jan. 1917. 



