﻿88 
  Prof. 
  C. 
  Barus 
  on 
  the 
  Behaviour 
  of 
  the 
  

  

  are 
  shown 
  graphically 
  in 
  fig. 
  3, 
  as 
  ordinates 
  in 
  terms 
  of 
  R 
  as 
  

   abscissas. 
  The 
  curve 
  here 
  is 
  apparently 
  sinuous, 
  due 
  to 
  the 
  

   abnormally 
  high 
  values 
  of 
  K 
  6 
  and 
  the 
  abnormally 
  low 
  values 
  

   of 
  K4, 
  alluded 
  to, 
  both 
  of 
  which 
  remain 
  unexplained. 
  In 
  

   the 
  absence 
  of 
  these 
  there 
  would 
  be 
  a 
  rise 
  of 
  %K', 
  of 
  a 
  gradual 
  

   character 
  with 
  increasing 
  radius. 
  Since 
  in 
  %K, 
  K 
  is 
  constant, 
  

   this 
  means 
  that 
  relatively 
  more 
  ions, 
  n 
  x 
  , 
  are 
  available 
  at 
  the 
  

   larger 
  radii 
  of 
  the 
  condensers, 
  corresponding 
  to 
  weaker 
  fields, 
  

   than 
  for 
  smaller 
  radii 
  and 
  correspondingly 
  stronger 
  fields. 
  But 
  

   as 
  there 
  is 
  no 
  reason 
  for 
  excluding 
  K4 
  and 
  K 
  6, 
  and 
  no 
  

   suggestion 
  for 
  the 
  occurrence 
  of 
  the 
  sinuous 
  curve 
  obtained, 
  

   WjK 
  must 
  be 
  regarded 
  as 
  increasing 
  rapidly 
  from 
  the 
  values 
  

   for 
  condensers 
  of 
  small 
  radii, 
  r 
  = 
  2 
  centim., 
  but 
  reaching 
  a 
  

   practically 
  constant 
  result 
  after 
  the 
  radius 
  4 
  centim. 
  has 
  been 
  

   surpassed. 
  On 
  the 
  whole, 
  therefore, 
  the 
  data 
  so 
  far 
  as 
  

   investigation 
  has 
  been 
  possible 
  agree 
  with 
  the 
  remarks 
  made 
  

   in 
  § 
  1, 
  that 
  the 
  evidence 
  in 
  case 
  of 
  dilution 
  is 
  rather 
  in 
  favour 
  

   of 
  an 
  increased 
  number 
  of 
  ions 
  and 
  that 
  an 
  occurrence 
  of 
  

   decay 
  is 
  not 
  manifest. 
  This 
  means 
  more 
  generally 
  that 
  

   whereas 
  in 
  the 
  saturated 
  emanation 
  the 
  ions 
  are 
  produced 
  at 
  

   the 
  same 
  rate 
  at 
  which 
  they 
  decay 
  so 
  that 
  n 
  is 
  constant, 
  in 
  

   the 
  diluted 
  emanation 
  at 
  a 
  distance 
  from 
  the 
  centre 
  (n 
  = 
  n 
  l 
  /r 
  <2 
  ), 
  

   the 
  production 
  is 
  in 
  excess 
  of 
  the 
  decay 
  and 
  conduction 
  

   relatively 
  too 
  great. 
  

  

  Another 
  method 
  of 
  treating 
  ^iK, 
  is 
  to 
  refer 
  it 
  to 
  strength 
  

   of 
  field. 
  This, 
  however, 
  may 
  be 
  done 
  more 
  advantageously 
  

   after 
  the 
  data 
  of 
  the 
  next 
  section, 
  in 
  which 
  R 
  is 
  constant 
  and 
  

   V 
  variable, 
  have 
  been 
  similarly 
  brought 
  forward. 
  

  

  10. 
  One 
  important 
  question 
  as 
  to 
  the 
  availability 
  of 
  

   phosphorus 
  as 
  an 
  ion 
  producer, 
  is 
  the 
  intensity 
  of 
  its 
  action 
  

   or 
  the 
  number 
  of 
  ions 
  produced 
  per 
  second 
  in 
  limiting 
  cases. 
  

   To 
  make 
  an 
  estimate 
  of 
  this 
  quality, 
  it 
  suffices 
  to 
  pass 
  a 
  current 
  

   through 
  the 
  condenser 
  for 
  gradually 
  increasing 
  potential- 
  

   differences 
  between 
  the 
  faces, 
  in 
  order 
  to 
  ascertain 
  to 
  what 
  

   degree 
  the 
  phenomenon 
  fails 
  to 
  obey 
  Ohm's 
  law. 
  

  

  Results 
  to 
  this 
  end 
  were 
  obtained 
  with 
  the 
  spherical 
  

   condenser, 
  K 
  4, 
  diameter 
  13*0 
  centims., 
  the 
  internal 
  surface 
  

   (a 
  copper 
  gauze 
  bag 
  carrying 
  phosphorus) 
  being 
  about 
  

   1 
  centim. 
  in 
  diameter. 
  Potential-differences, 
  V, 
  as 
  high 
  as 
  

   200 
  volts 
  were 
  applied, 
  the 
  external 
  surface 
  being 
  put 
  to 
  

   earth. 
  The 
  current 
  is 
  as 
  usual 
  found 
  from 
  equidistant 
  obser- 
  

   vations 
  separated 
  by 
  an 
  interval 
  of 
  3 
  minutes. 
  A 
  few 
  test 
  

   experiments 
  were 
  made 
  by 
  repeating 
  the 
  earlier 
  measurements 
  

   for 
  21 
  and 
  63 
  volts, 
  but 
  it 
  was 
  thought 
  wisest 
  not 
  to 
  attempt 
  

   to 
  correct 
  the 
  data 
  for 
  the 
  fluctuating 
  ionizing 
  activity 
  of 
  

   phosphorus 
  in 
  the 
  lapse 
  of 
  time, 
  nor 
  to 
  assume 
  curvature 
  in 
  

  

  