﻿478 
  

  

  Mr. 
  L. 
  Vegard 
  on 
  the 
  Electric 
  Discharge 
  

  

  Absorption 
  in 
  Oxygen. 
  

  

  § 
  14. 
  As 
  long 
  as 
  the 
  i^ressure 
  is 
  fairly 
  high 
  the 
  absorption 
  

   is 
  extremely 
  small 
  even 
  for 
  very 
  large 
  currents. 
  — 
  A 
  current 
  

   o£ 
  157 
  . 
  10~^ 
  am. 
  with 
  a 
  pressure 
  so 
  low 
  as 
  0*8 
  mm. 
  gave 
  

   5' 
  = 
  0'006. 
  With 
  a 
  pressure 
  of 
  0*56 
  mm. 
  and 
  a 
  current 
  of 
  

   116 
  . 
  10"^ 
  am. 
  the 
  discharge 
  could 
  no 
  longer 
  be 
  kept 
  constant. 
  

   Current 
  and 
  pressure 
  decreased 
  rapidljj 
  until 
  after 
  25 
  min. 
  

   the 
  current 
  had 
  fallen 
  to 
  0*38 
  . 
  10~^ 
  and 
  the 
  pressure 
  di- 
  

   minished 
  to 
  0*13 
  mm. 
  The 
  average 
  current 
  in 
  the 
  interval 
  

   was 
  42*5 
  . 
  10"^ 
  am., 
  which 
  gives 
  the 
  average 
  value 
  of 
  ^ 
  = 
  0*21, 
  

   or 
  more 
  than 
  thirty 
  times 
  as 
  large 
  as 
  the 
  value 
  at 
  the 
  some- 
  

   what 
  higher 
  pressure. 
  The 
  rapid 
  absorption 
  set 
  in 
  with 
  a 
  

   cathode 
  fall 
  of 
  about 
  650 
  volts. 
  . 
  

  

  Another 
  experiment 
  was 
  tried 
  with 
  a 
  pressure 
  0*27 
  mm., 
  

   but 
  in 
  this 
  case 
  the 
  discharge 
  was 
  commenced 
  with 
  small 
  

   currents. 
  In 
  spite 
  of 
  the 
  smaller 
  pressure 
  it 
  was 
  found 
  that 
  

   for 
  currents 
  below 
  a 
  certain 
  value 
  the 
  discharge 
  could 
  be 
  kept 
  

   constant 
  and 
  the 
  absorjjtion 
  teas 
  inappreciable. 
  Currents 
  

   from 
  0'5 
  . 
  10"^ 
  to 
  14.10"^^ 
  am. 
  were 
  allowed 
  to 
  pass 
  for 
  

   about 
  15 
  min. 
  each, 
  but 
  no 
  change 
  in 
  pressure 
  was 
  observ- 
  

   able 
  ; 
  with 
  a 
  current 
  of 
  40 
  . 
  10~^ 
  the 
  pressure 
  and 
  current 
  

   began 
  to 
  decrease. 
  The 
  variation 
  of 
  the 
  properties 
  of 
  dis- 
  

   charge 
  during 
  the 
  " 
  running 
  down 
  " 
  of 
  the 
  tube 
  is 
  given 
  in 
  

   Table 
  VIII., 
  and 
  the 
  variation 
  of 
  current, 
  pressure, 
  and 
  q 
  is 
  

   represented 
  in 
  fig. 
  13. 
  

  

  Table 
  VIII. 
  

  

  Time. 
  

  

  lO^I. 
  

   40 
  

  

  P- 
  

  

  Gm. 
  

  

  Cathode- 
  

   fall. 
  

  

  Z^- 
  

  

  ?• 
  

  

  

  

  0-27 
  

  

  140 
  

  

  640 
  

  

  

  

  2-5 
  

  

  39-5 
  

  

  026 
  

  

  

  660 
  

  

  4-0.10-5 
  

  

  010 
  

  

  5 
  

  

  38-5 
  

  

  0-22 
  

  

  ... 
  

  

  800 
  

  

  7-5 
  „ 
  

  

  0-20 
  

  

  8 
  

  

  35 
  

  

  016 
  

  

  

  

  9-5 
  „ 
  

  

  0-27 
  

  

  12 
  

  

  12 
  

  

  Oil 
  

  

  ... 
  

  

  

  31 
  „ 
  

  

  0-26 
  

  

  18 
  

  

  5-0 
  

  

  0094 
  

  

  ... 
  

  

  1220 
  

  

  1-34 
  „ 
  

  

  0-27 
  

  

  23 
  

  

  2-7 
  

  

  0-088 
  

  

  

  1260 
  

  

  0-64 
  „ 
  

  

  0-24 
  

  

  29 
  

  

  20 
  

  

  0-075 
  

  

  1-0 
  

  

  1265 
  

  

  0-56 
  „ 
  

  

  0-28 
  

  

  1 
  

  

  We 
  see 
  that 
  the 
  quantity 
  {q) 
  shows 
  a 
  very 
  simple 
  variation 
  

   in 
  spite 
  of 
  the 
  rather 
  complicated 
  manner 
  in 
  which 
  current 
  

   and 
  pressure 
  vary. 
  The 
  value 
  of 
  q 
  increases 
  to 
  a 
  maximum 
  

   value, 
  after 
  which 
  it 
  keeps 
  constant, 
  and 
  the 
  maximum 
  value 
  

   is 
  of 
  the 
  order 
  of 
  the 
  electrochemical 
  equivalent. 
  

  

  