﻿COHEN. 
  

  

  Fig. 
  5. 
  

  

  Vibrating 
  Wire. 
  

   Details 
  of 
  mercury 
  cups, 
  etc. 
  

  

  Vibrating 
  Wire 
  Interrupter. 
  

   General 
  View. 
  

  

  