﻿Lime 
  for 
  the 
  Wehnelt 
  Cathode. 
  

  

  593 
  

  

  Method. 
  

  

  The 
  electrons 
  fell 
  upon 
  the 
  disc 
  G\ 
  located 
  opposite 
  and 
  

  

  about 
  4 
  mm 
  from 
  the 
  cathode, 
  and 
  the 
  resulting 
  current 
  was 
  

  

  indicated 
  by 
  the 
  galvanometer! 
  With 
  each 
  galvanometer 
  

  

  reading, 
  which 
  was 
  the 
  mean 
  of 
  two 
  deflections, 
  the 
  pressure, 
  

  

  Fig. 
  3. 
  

  

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  eti 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

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  3 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

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  - 
  i 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

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  5— 
  Ca 
  

  

  

  

  

  

  

  

  

  

  

  

  "fl 
  

  

  

  J 
  

  

  

  

  

  

  30 
  60 
  90 
  !20 
  

  

  Time 
  in 
  minutes 
  

  

  150 
  

  

  180 
  210 
  

  

  240 
  

  

  270 
  

  

  discharge 
  voltage, 
  and 
  heating 
  current 
  readings 
  were 
  taken. 
  

   The 
  heating 
  current 
  was 
  kept 
  strictly 
  constant. 
  The 
  pressure 
  

   was 
  also 
  kept 
  practically 
  constant 
  by 
  occasional 
  pumping. 
  

  

  After 
  mounting 
  the 
  platinum 
  strip, 
  a 
  very 
  small 
  piece 
  of 
  the 
  

   red 
  wax 
  was 
  placed 
  centrally 
  upon 
  it. 
  The 
  wires 
  D 
  and 
  E' 
  

   were 
  then 
  connected 
  to 
  the 
  heating 
  circuit 
  and 
  the 
  current 
  was 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XXXVI, 
  jSo. 
  216. 
  — 
  December, 
  1913. 
  

   40 
  

  

  