﻿from 
  Actinium 
  in 
  Uniform 
  Electric 
  Fields* 
  

  

  751 
  

  

  obtained 
  with 
  air, 
  and 
  that 
  the 
  deposits 
  on 
  the 
  two 
  electrodes 
  

   gradually 
  increased 
  as 
  the 
  pressure 
  was 
  lowered. 
  Both 
  

   passed 
  through 
  a 
  maximum, 
  and 
  for 
  still 
  lower 
  pressures 
  the 
  

   active 
  deposit 
  on 
  both 
  plates 
  decreased 
  and 
  approached 
  

   equality 
  for 
  the 
  lowest 
  pressures 
  investigated. 
  The 
  maximum 
  

   activity 
  on 
  the 
  negative 
  electrode 
  was 
  obtained 
  at 
  a 
  pressure 
  

   of 
  60 
  mm., 
  while 
  the 
  maximum 
  active 
  deposit 
  on 
  the 
  positive 
  

   terminal 
  was 
  not 
  obtained 
  until 
  the 
  pressure 
  was 
  14 
  mm. 
  

   The 
  maximum 
  active 
  deposit 
  on 
  the 
  cathode 
  was 
  about 
  2'^^ 
  

   times 
  the 
  maximum 
  deposit 
  on 
  the 
  anode, 
  and 
  this, 
  it 
  will 
  be 
  

   seen, 
  is 
  not 
  very 
  different 
  from 
  the 
  ratio 
  which 
  was 
  found 
  for 
  

   the 
  maximum 
  activities 
  obtained 
  in 
  the 
  case 
  of 
  air. 
  Care 
  was 
  

   taken 
  in 
  the 
  experiments 
  with 
  carbon 
  dioxide 
  and 
  air 
  to 
  

   repeat 
  all 
  the 
  observations 
  a 
  number 
  of 
  times, 
  and 
  the 
  curves 
  

   indicated 
  in 
  figs. 
  7 
  and 
  11 
  (PI. 
  XXII.) 
  were 
  uniformly 
  

   obtained 
  for 
  the 
  two 
  gases 
  under 
  the 
  conditions 
  described. 
  

  

  VIII. 
  Activity 
  of 
  Deposits 
  obtained 
  in 
  Hydrogen 
  at 
  

   different 
  Pressures. 
  

  

  Another 
  series 
  of 
  measurements 
  was 
  made 
  with 
  hydrogen, 
  

   under 
  conditions 
  similar 
  to 
  those 
  already 
  described 
  with 
  air 
  

   and 
  carbon 
  dioxide, 
  and 
  the 
  active 
  deposits 
  obtained 
  at 
  the 
  

   various 
  pressures 
  are 
  given 
  in 
  Table 
  V., 
  and 
  a 
  curve 
  repre- 
  

   senting 
  them 
  in 
  fig. 
  13 
  (PL 
  XXII.). 
  From 
  these 
  observations 
  

  

  Table 
  V. 
  

  

  Pressure. 
  

  

  Activity 
  on 
  the 
  

   Cathode. 
  

  

  Activity 
  on 
  the 
  

   Anode. 
  

  

  6 
  mm. 
  

  

  21-0 
  

  

  20-0 
  

  

  46 
  ,, 
  

  

  520 
  

  

  430 
  

  

  117 
  „ 
  

  

  83-0 
  

  

  43-7 
  

  

  235 
  „ 
  

  

  106-0 
  

  

  27-7 
  

  

  457 
  „ 
  

  

  87-3 
  

  

  150. 
  

  

  760 
  „ 
  

  

  78-3 
  

  

  8-3 
  

  

  it 
  will 
  be 
  seen 
  again, 
  that 
  as 
  the 
  pressure 
  was 
  lowered, 
  

   the 
  active 
  deposits 
  on 
  both 
  electrodes 
  steadily 
  increased, 
  

   passed 
  through 
  maximum 
  values, 
  decreased, 
  and 
  on 
  the 
  de- 
  

   crease 
  approached 
  equality 
  at 
  the 
  lowest 
  pressures 
  examined. 
  

   In 
  hydrogen 
  the 
  maximum 
  active 
  deposit 
  on 
  the 
  cathode 
  was 
  

   obtained 
  at 
  about 
  250 
  mm., 
  but 
  the 
  maximum 
  active 
  deposit 
  

   on 
  the 
  anode 
  was 
  not 
  obtained 
  until 
  about 
  80 
  mm. 
  pressure 
  

   was 
  reached. 
  The 
  maximum 
  active 
  deposit 
  on 
  the 
  negative 
  

  

  