﻿384 
  A. 
  G. 
  Webster 
  —Rapid 
  Break 
  for 
  large 
  Currents. 
  

  

  adopted 
  is 
  shown 
  in 
  fig. 
  1, 
  the 
  elevator 
  being 
  on 
  the 
  left. 
  An 
  

   aspirating 
  water-pump 
  is 
  connected 
  to 
  the 
  tube 
  C, 
  at 
  the 
  end 
  

  

  K' 
  

  

  of 
  the 
  supply-tube 
  A, 
  which 
  contains 
  mercury 
  at 
  the 
  start. 
  On 
  

   account 
  of 
  the 
  vacuum, 
  the 
  mercury 
  to 
  be 
  elevated, 
  contained 
  in 
  

   the 
  cups 
  K 
  and 
  K', 
  which 
  are 
  connected 
  by 
  a 
  small 
  rubber 
  tube, 
  

   rises 
  m 
  the 
  tubes 
  R 
  and 
  V, 
  while 
  the 
  mercury 
  in 
  the 
  discharge 
  

   tube 
  S 
  descends. 
  Owing 
  to 
  the 
  large 
  size 
  of 
  the 
  tube 
  V, 
  the 
  

   level 
  in 
  K 
  descends 
  rapidly, 
  followed 
  by 
  that 
  in 
  K', 
  so 
  that 
  the 
  

   end 
  of 
  the 
  tube 
  R 
  is 
  exposed 
  to 
  the 
  air, 
  which 
  raises 
  the 
  

   column 
  of 
  mercury 
  in 
  R. 
  When 
  the 
  column 
  passes 
  the 
  con- 
  

  

  