﻿192 
  

  

  Mr. 
  J. 
  H. 
  Vincent 
  on 
  the 
  

  

  dryness. 
  The 
  latter 
  was 
  sacrificed 
  to 
  obtain 
  the 
  former, 
  and 
  

   the 
  apparatus 
  was 
  set 
  up 
  in 
  a 
  cellar 
  with 
  a 
  concrete 
  floor 
  and 
  

   bricked 
  roof. 
  The 
  disadvantage 
  of 
  the 
  induction-machine 
  

  

  Diagram 
  of 
  Apparatus. 
  

  

  ** 
  

  

  s«0 
  

  

  A 
  

  

  j\ 
  nat. 
  size. 
  

  

  T. 
  Mercury 
  trough. 
  

  

  A. 
  Iron 
  standard 
  supporting 
  T. 
  

  

  B. 
  Wooden 
  block. 
  

  

  C. 
  Iron 
  hook 
  in 
  the 
  roof. 
  

  

  E. 
  String. 
  

  

  S. 
  First 
  spark-gap. 
  

  

  L. 
  Lens. 
  

  

  D. 
  Camera. 
  

  

  