﻿Rout 
  (if 
  en 
  Rays 
  by 
  Aqueous 
  Solution 
  

  

  71 
  

  

  variations 
  in 
  the 
  intensity 
  of 
  the 
  radiation, 
  presented 
  itself. 
  In 
  

   order 
  to 
  overcome 
  this 
  difficulty, 
  another 
  box, 
  similar 
  to 
  the 
  

   one 
  used 
  to 
  contain 
  the 
  liquid, 
  was 
  made; 
  and 
  this 
  box, 
  filled 
  

   with 
  water, 
  was 
  used 
  as 
  a 
  standard 
  with 
  which 
  all 
  the 
  other 
  

   measurements 
  were 
  compared. 
  The 
  method 
  of 
  taking 
  the 
  

   observations 
  was 
  as 
  follows 
  : 
  — 
  The 
  standard 
  cell, 
  filled 
  with 
  

   water, 
  was 
  placed 
  in 
  position, 
  and 
  the 
  rate 
  of 
  leak 
  per 
  second, 
  

   as 
  indicated 
  by 
  the 
  deflexion 
  of 
  the 
  electrometer-needle, 
  taken. 
  

   Several 
  readings 
  in 
  succession 
  were 
  made 
  and 
  the 
  mean 
  of 
  

   these 
  taken. 
  As 
  the 
  X-ray 
  bulb 
  usually 
  gives 
  out 
  rays 
  more 
  

   uniform 
  in 
  intensity 
  when 
  run 
  regularly, 
  the 
  observations 
  

   were 
  taken 
  at 
  regular 
  intervals 
  of 
  about 
  a 
  minute 
  and 
  a 
  half. 
  

   The 
  bulb 
  was 
  run 
  for 
  ten 
  seconds 
  before 
  taking 
  the 
  deflexion, 
  

   so 
  as 
  to 
  insure 
  that 
  the 
  ionization 
  would 
  reach 
  a 
  maximum, 
  

   and 
  at 
  the 
  end 
  of 
  this 
  time, 
  the 
  one 
  pair 
  of 
  quadrants 
  of 
  the 
  

   electrometer 
  were 
  insulated, 
  and 
  the 
  deflexion 
  of 
  the 
  needle 
  

   in 
  a 
  certain 
  time 
  observed, 
  the 
  time 
  being 
  taken 
  by 
  means 
  of 
  

   a 
  stop-watch. 
  Now, 
  if 
  the 
  intensity 
  of 
  the 
  radiation 
  remains 
  

   constant, 
  this 
  deflexion 
  should 
  remain 
  constant 
  also 
  ; 
  however, 
  

   if 
  the 
  intensity 
  changes, 
  this 
  deflexion 
  will 
  change 
  in 
  the 
  

   same 
  ratio. 
  

  

  After 
  taking 
  the 
  deflexion 
  for 
  the 
  standard 
  cell 
  filled 
  with 
  

   water, 
  it 
  was 
  removed, 
  and 
  the 
  other 
  cell 
  (which 
  we 
  may 
  

   call 
  Cell 
  II.) 
  was 
  placed 
  in 
  exactly 
  the 
  same 
  position 
  and 
  a 
  

   corresponding 
  set 
  of 
  deflexions 
  observed. 
  This 
  was 
  again 
  

   removed, 
  and 
  a 
  set 
  of 
  readings 
  taken 
  with 
  the 
  standard 
  in 
  

   place. 
  Replacing 
  the 
  standard 
  by 
  Cell 
  II., 
  filled 
  with 
  water, 
  

   the 
  operation 
  was 
  repeated. 
  This 
  method 
  of 
  alternate 
  sets 
  of 
  

   readings 
  was 
  continued 
  throughout 
  a 
  whole 
  series 
  of 
  observa- 
  

   tions. 
  Each 
  set 
  of 
  observations 
  being 
  thus 
  followed 
  by 
  a 
  set 
  

   taken 
  with 
  the 
  standard 
  in 
  place, 
  any 
  variation 
  in 
  the 
  rays 
  

   would 
  be 
  indicated 
  by 
  the 
  difference 
  in 
  deflexion 
  produced 
  by 
  

   the 
  standard, 
  and 
  therefore 
  all 
  the 
  readings 
  could 
  be 
  com- 
  

   pared 
  with 
  one 
  another 
  by 
  simply 
  reducing 
  them 
  to 
  the 
  

   same 
  basis. 
  A 
  sample 
  of 
  such 
  a 
  set 
  of 
  readings 
  is 
  shown 
  below. 
  

  

  Cell. 
  

  

  Mean 
  deflexion 
  per 
  sec. 
  

  

  Standard 
  

  

  150^ 
  

  

  Cell 
  II. 
  with 
  water 
  ... 
  

  

  16-6 
  ^15-8 
  

  

  Standard 
  

  

  166^ 
  

  

  Cell 
  II. 
  empty 
  

  

  48-2 
  >16-3 
  

  

  Standard 
  

  

  i6-(r 
  

  

  