﻿On 
  the 
  Transformations 
  of 
  X-Bays. 
  107 
  

  

  If 
  we 
  take 
  the 
  amount 
  of 
  radium 
  in 
  sea-water 
  as 
  10~^^ 
  

   gram 
  per 
  gram 
  of 
  water, 
  and 
  in 
  the 
  soil 
  as 
  4 
  x 
  10 
  "^^ 
  a 
  simple 
  

   calculation 
  * 
  shows 
  that 
  the 
  penetrating 
  radiation 
  from 
  the 
  

   soil 
  should 
  be 
  about 
  1600 
  times 
  as 
  great 
  as 
  from 
  the 
  ocean, 
  

   so 
  far 
  as 
  tlie 
  penetrating 
  radiation 
  may 
  be 
  attributed 
  to 
  the 
  

   presence 
  of 
  radium. 
  

  

  If 
  we 
  follow 
  a 
  calculation 
  of 
  Becker 
  f, 
  ^ve 
  find 
  the 
  radium 
  

   contents 
  of 
  the 
  ocean 
  to 
  be 
  equivalent 
  to 
  the 
  radium 
  found 
  

   in 
  a 
  very 
  small 
  thickness 
  of 
  the 
  deposits 
  at 
  the 
  bottom 
  of 
  

   the 
  ocean. 
  Let 
  us 
  suppose 
  the 
  ocean 
  contains 
  9 
  x 
  lO"'"", 
  the 
  

   deep-sea 
  deposits 
  25x10"^^ 
  ('^oly), 
  and 
  the 
  sedimentary 
  

   rocks 
  I'l 
  X 
  10"^^ 
  (Strutt), 
  in 
  each 
  case 
  in 
  terms 
  of 
  grams 
  of 
  

   radium 
  per 
  gram 
  of 
  material. 
  Take 
  the 
  mean 
  depth 
  of 
  the 
  

   ocean 
  as 
  3*5 
  kilometres 
  and 
  the 
  specific 
  gravity 
  of 
  the 
  deposit 
  

   or 
  soil 
  as 
  2*5. 
  Then 
  the 
  amount 
  of 
  radium 
  in 
  3*5 
  km. 
  depth 
  

   of 
  oeenn, 
  per 
  sq. 
  cm 
  , 
  is 
  about 
  equal 
  to 
  that, 
  also 
  per 
  sq. 
  cm 
  , 
  

   in 
  114 
  cms. 
  of 
  sedimentary 
  rock, 
  or 
  5 
  cms. 
  of 
  deep-sea 
  

   deposit. 
  

  

  Summary. 
  

  

  1. 
  Radium 
  emanation 
  may 
  be 
  collected 
  over 
  water 
  or 
  over 
  

   mercury 
  with 
  about 
  equal 
  accuracy 
  when 
  testing 
  for 
  the 
  

   quantity 
  present 
  in 
  a 
  given 
  solution. 
  

  

  2. 
  The 
  result 
  of 
  testing 
  six 
  samples 
  of 
  sea-water 
  from 
  the 
  

   North 
  Atlantic 
  leads 
  to 
  the 
  average 
  value 
  of 
  9 
  x 
  10"^^ 
  gram 
  

   of 
  radium 
  per 
  gram 
  of 
  sea-water. 
  This 
  is 
  about 
  one-seven- 
  

   teenth 
  of 
  the 
  value 
  found 
  by 
  Joly. 
  

  

  Montreal, 
  April 
  1909. 
  

  

  XI. 
  Transformations 
  of 
  X-Rays. 
  By 
  Charles 
  A. 
  Sadler, 
  

   M.Sc, 
  Oliver 
  Lodge 
  Fellow, 
  University 
  of 
  Liverpool 
  X. 
  

  

  WHEN 
  a 
  primary 
  beam 
  of 
  Rontgen 
  radiation 
  falls 
  upon 
  

   any 
  substance, 
  secondary 
  Rontgen 
  rays 
  are 
  emitted, 
  

   the 
  character 
  of 
  which 
  depends 
  both 
  upon 
  the 
  nature 
  of 
  the 
  

   substance 
  and 
  upon 
  the 
  particular 
  kind 
  of 
  primary 
  beam 
  

   used. 
  With 
  reference 
  to 
  the 
  latter 
  it 
  has 
  been 
  found 
  that 
  

   variations 
  in 
  the 
  intensity 
  of 
  the 
  primary 
  beam 
  produce 
  no 
  

   perceptible 
  change 
  in 
  the 
  character 
  of 
  the 
  resulting 
  secondary, 
  

   the 
  sole 
  controlling 
  factor 
  appearing 
  to 
  be 
  the 
  degree 
  of 
  

   " 
  hardness 
  " 
  of 
  the 
  primary 
  §. 
  

  

  * 
  ' 
  Terrestrial 
  Maguetism,' 
  March 
  1909. 
  

  

  t 
  Bull. 
  Geol. 
  Soc. 
  of 
  America, 
  vol. 
  xix. 
  p 
  113 
  (1908). 
  

  

  i 
  Communicated 
  by 
  the 
  Physical 
  Society 
  : 
  read 
  April 
  23, 
  1009. 
  

  

  § 
  Barkla, 
  Phil. 
  Mag. 
  Jane 
  1906, 
  pp. 
  812-828. 
  

  

  