﻿from 
  Actinium 
  in 
  Uniform 
  Electric 
  Fields. 
  753 
  

  

  o£ 
  a 
  maximum 
  effect 
  in 
  the 
  three 
  gases, 
  and 
  consequently 
  

   for 
  the 
  critical 
  pressures 
  given 
  above, 
  deduce 
  an 
  approximate 
  

   estimate 
  of 
  the 
  ratios 
  of 
  the 
  coefficient 
  of 
  diffusion 
  of 
  the 
  

   active 
  product 
  or 
  products 
  into 
  the 
  three 
  gases 
  at 
  atmospheric 
  

   pressure. 
  These 
  follow 
  directly 
  from 
  the 
  argument 
  just 
  

   presented, 
  and 
  are 
  given 
  in 
  Table 
  TIL 
  

  

  Table 
  VIL 
  

  

  Ga3. 
  

  

  Pressure 
  for 
  maximum 
  

  

  Active 
  Deposit 
  on 
  

  

  the 
  Cathode. 
  

  

  Calculated 
  Ratios 
  of 
  

  

  the 
  Coefficient 
  of 
  

  

  Diffusion 
  of 
  the 
  Active 
  

  

  Product 
  into 
  the 
  

  

  different 
  G-ases 
  at 
  

  

  Atmospheric 
  Pressure. 
  

  

  Carbon 
  Dioxide 
  

  

  60 
  

  

  80 
  

  

  250 
  

  

  1 
  

  

  Air 
  

  

  1-3 
  

  

  

  4-2 
  

  

  

  

  Followino- 
  the 
  same 
  line 
  of 
  aroument 
  in 
  cnse 
  of 
  the 
  anode 
  

   deposits, 
  since 
  the 
  maximum 
  effects 
  were 
  obtained 
  at 
  pressures 
  

   14 
  mm., 
  17 
  mm., 
  and 
  80 
  mm., 
  for 
  carbon 
  dioxide, 
  air, 
  and 
  

   hydrogen 
  respectively, 
  it 
  follows 
  that 
  the 
  ratios 
  of 
  the 
  co- 
  

   efficients 
  of 
  diffusion 
  of 
  the 
  active 
  products 
  concerned 
  were 
  

   as 
  1 
  : 
  1'21 
  : 
  5*7, 
  i. 
  e. 
  the 
  relative 
  coefficient 
  for 
  air 
  was 
  slightly 
  

   lower 
  and 
  that 
  for 
  hydrogen 
  slightly 
  higher 
  than 
  the 
  values 
  

   deduced 
  from 
  the 
  behaviour 
  of 
  the 
  cathode 
  deposits. 
  

  

  The 
  ratios 
  of 
  the 
  coefficients 
  of 
  diffusion 
  of 
  the 
  active 
  pro- 
  

   duct 
  concerned, 
  as 
  deduced 
  from 
  the 
  cathode 
  deposits, 
  are 
  

   practically 
  the 
  same 
  as 
  some 
  values 
  given 
  in 
  a 
  paper 
  by 
  

   Russ 
  *; 
  and 
  this 
  agreement 
  goes 
  to 
  show 
  that 
  it 
  is 
  a 
  diffusion 
  

   phenomenon 
  which 
  is 
  the 
  paramount 
  one 
  in 
  the 
  present 
  

   investigation. 
  

  

  The 
  interpretation 
  of 
  the 
  maximum 
  effect 
  obtained 
  on 
  each 
  

   electrode 
  with 
  the 
  three 
  gases, 
  however, 
  presents 
  some 
  

   difficulty. 
  One 
  should 
  have 
  expected, 
  with 
  the 
  active 
  deposits 
  

   in 
  the 
  experiments 
  in 
  which 
  the 
  salt 
  was 
  placed 
  at 
  different 
  

   distances 
  from 
  the 
  electrodes, 
  that 
  in 
  the 
  case 
  of 
  the 
  lowest 
  

   pressures 
  a 
  maximum 
  value 
  would 
  have 
  been 
  obtained 
  for 
  a 
  

   certain 
  critical 
  distance 
  of 
  the 
  salt 
  from 
  the 
  plates. 
  But, 
  as 
  

   the 
  curves 
  in 
  figs. 
  5 
  and 
  6 
  (PI. 
  XXII.) 
  show, 
  no 
  such 
  maximum 
  

   values 
  appeared. 
  

  

  ♦ 
  Russ, 
  Phi]. 
  Mug. 
  March 
  1901). 
  

  

  