﻿from 
  Actinium 
  in 
  Uniform 
  Electric 
  Fields. 
  

  

  749 
  

  

  them 
  are 
  drawn 
  in 
  figs. 
  3, 
  4, 
  5, 
  and 
  6 
  (PL 
  XXII.). 
  From 
  the 
  

   numbers 
  given 
  and 
  from 
  the 
  form 
  of 
  the 
  curves 
  it 
  will 
  be 
  

   seen 
  that 
  for 
  all 
  pressures 
  the 
  activity 
  obtained 
  on 
  both 
  

   electrodes 
  steadily 
  decreased 
  as 
  the 
  distance 
  between 
  the 
  salt 
  

   and 
  the 
  electrodes 
  was 
  increased. 
  This 
  result, 
  it 
  will 
  be 
  seen, 
  

   is 
  somewhat 
  different 
  from 
  that 
  obtained 
  by 
  Russ 
  with 
  his 
  

   apparatus, 
  for, 
  as 
  stated 
  above, 
  he 
  found 
  at 
  certain 
  pressures 
  

   that 
  the 
  active 
  deposits 
  slightly 
  increased 
  as 
  the 
  salt 
  was 
  

   removed, 
  attained 
  maximum 
  values 
  at 
  certain 
  distances, 
  and 
  

   finally 
  fell 
  away 
  as 
  the 
  salt 
  was 
  still 
  further 
  removed. 
  

  

  VI. 
  Activity 
  of 
  Deposits 
  in 
  Air 
  dependent 
  upon 
  Pressure. 
  

  

  The 
  next 
  variation 
  made 
  in 
  the 
  experiments 
  was 
  to 
  keep 
  

   the 
  electrodes 
  at 
  a 
  constant 
  distance 
  apart, 
  2 
  mm., 
  and 
  the 
  

   salt 
  at 
  a 
  fixed 
  distance 
  11 
  mm. 
  from 
  them, 
  while 
  the 
  pres- 
  

   sure 
  of 
  the 
  air 
  was 
  gradually 
  lowered, 
  and 
  the 
  activity 
  of 
  

   the 
  deposits 
  corresponding 
  to 
  different 
  pressures 
  was 
  measured. 
  

   The 
  range 
  of 
  pressures 
  investigated 
  was 
  from 
  750 
  to 
  '5 
  mm. 
  

   of 
  mercury. 
  Table 
  III. 
  gives 
  the 
  results 
  for 
  air, 
  and 
  

  

  Table 
  III. 
  

  

  Pressure. 
  

  

  Activity 
  on 
  the 
  

   Cathode. 
  

  

  Activity 
  ou 
  the 
  

   Anode. 
  

  

  •5 
  mm. 
  

  

  11-7 
  

  

  11-3 
  

  

  10 
  „ 
  

  

  14-5 
  

  

  140 
  

  

  20 
  „ 
  

  

  18-5 
  

  

  170 
  

  

  7-5 
  „ 
  

  

  37-5 
  

  

  29-0 
  

  

  12-0 
  „ 
  

  

  49-0 
  

  

  330 
  

  

  250 
  ., 
  

  

  62-5 
  

  

  28-5 
  

  

  42-0 
  i, 
  

  

  82-3 
  

  

  17-7 
  i 
  

  

  72-0 
  „ 
  

  

  920 
  

  

  10-0 
  I 
  

  

  92-0 
  „ 
  

  

  91-0 
  

  

  7-5 
  ; 
  

  

  1200 
  „ 
  

  

  76-0 
  

  

  -6-0 
  

  

  1350 
  „ 
  

  

  73-0 
  

  

  50 
  

  

  1620 
  „ 
  

  

  68-0 
  

  

  4-0 
  

  

  1920 
  „ 
  

  

  66-5 
  

  

  30 
  

  

  3200 
  „ 
  

  

  43-0 
  

  

  M5 
  

  

  500-0 
  „ 
  

  

  31-0 
  

  

  •70 
  

  

  750-0 
  „ 
  

  

  20-5 
  

  

  •45 
  

  

  figs. 
  7, 
  c5, 
  and 
  9 
  (PL 
  XXII.) 
  were 
  drawn 
  from 
  them, 
  and 
  

   illustrate 
  the 
  manner 
  in 
  which 
  the 
  deposits 
  occurred 
  at 
  the 
  

   various 
  pressures. 
  The 
  curves 
  for 
  both 
  electrodes, 
  it 
  will 
  

   be 
  seen, 
  follow 
  similar 
  laws. 
  The 
  activities 
  on 
  both 
  elec- 
  

   trodes 
  steadily 
  rose 
  as 
  the 
  pressure 
  fell, 
  both 
  passed 
  through 
  

   maximum 
  values, 
  and 
  both 
  fell 
  away 
  again 
  and 
  approached 
  

   equality 
  at 
  the 
  lowest 
  pressure. 
  

  

  