﻿;[ 
  G=ST 
  

  

  Phil.Mag. 
  Ser.6,Tol.l8.Pl.V. 
  

  

  but 
  plate 
  moved 
  s 
  

   bration- 
  curves 
  but 
  

   nations 
  of 
  amplitut 
  

  

  Plucked 
  at 
  h 
  

  

  10 
  

  

  