﻿688 
  

  

  Prof. 
  0. 
  W. 
  Richardson 
  on 
  the 
  Kinetic 
  

  

  very 
  big, 
  and 
  there 
  are 
  many 
  other 
  points 
  of 
  a 
  much 
  more 
  

   pressing 
  character 
  v^hich 
  can 
  be 
  satisfactorily 
  investigated 
  

   with 
  the 
  apparatus 
  in 
  its 
  present 
  state 
  of 
  development. 
  

  

  Fig. 
  3. 
  

  

  

  

  

  

  

  

  

  

  

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  H 
  

  

  10 
  le 
  14 
  16 
  IS 
  20 
  z.. 
  

  

  DisPL/ic£/viEN 
  T 
  or 
  Slj 
  

  

  Z 
  ZQr 
  26 
  £8 
  50 
  32 
  

  

  T 
  (I- 
  -0655 
  cm.) 
  

  

  34 
  36 
  33 
  4-0 
  

  

  The 
  results 
  of 
  a 
  typical 
  experiment 
  will 
  now 
  be 
  given: 
  — 
  

   The 
  electrometer 
  suspension 
  was 
  a 
  quartz 
  fibre, 
  and 
  the 
  

   needle 
  was 
  charged 
  to 
  a 
  potential 
  of 
  80 
  volts. 
  The 
  instru- 
  

   ment 
  then 
  gave 
  a 
  deflexion 
  of 
  437 
  divs. 
  for 
  a 
  volt, 
  and 
  the 
  

   spot 
  was 
  a 
  fine 
  line 
  about 
  one-fifth 
  of 
  a 
  millimetre 
  wide, 
  so 
  

   that 
  tenths 
  of 
  a 
  division 
  were 
  read. 
  It 
  is 
  necessary 
  to 
  use 
  a 
  

   sensitive 
  electrometer, 
  otherwise 
  the 
  back 
  electromotive 
  force 
  

   due 
  to 
  the 
  charging 
  up 
  of 
  the 
  plates 
  vitiates 
  the 
  results. 
  

   The 
  capacity 
  attached 
  to 
  the 
  slit-electrode 
  was 
  O'Ol 
  microfarad, 
  

   that 
  attached 
  to 
  the 
  plates 
  0*3 
  microfarad, 
  and 
  the 
  electro- 
  

   meter 
  and 
  its 
  connexions 
  had 
  a 
  capacity 
  of 
  180 
  cm. 
  The 
  

   capacity 
  for 
  the 
  slit-readings 
  was 
  therefore 
  9 
  x 
  10^ 
  + 
  180 
  cm., 
  

   and 
  that 
  for 
  the 
  plates 
  and 
  slit 
  together 
  27x10^ 
  + 
  9x103 
  

   + 
  180 
  cm. 
  The 
  temperature 
  when 
  the 
  readings 
  were 
  taken 
  

   with 
  the 
  current 
  direct 
  was 
  1034" 
  C, 
  and 
  the 
  pressure 
  about 
  

   •009 
  mm. 
  of 
  mercury. 
  When 
  the 
  current 
  was 
  reversed 
  the 
  

   temperature 
  was 
  1069° 
  C, 
  and 
  the 
  pressure 
  varied 
  from 
  '003 
  

   to 
  '005 
  mm., 
  the 
  average 
  pressure 
  being 
  about 
  '004 
  mm. 
  The 
  

   temperature 
  estimations 
  are 
  probably 
  only 
  accurate 
  to 
  within 
  

   about 
  20°. 
  The 
  values 
  found 
  are 
  given 
  in 
  the 
  subjoined 
  

   table. 
  

  

  