﻿Rontgen 
  Rays 
  by 
  Aqueous 
  Solutions. 
  79 
  

  

  Chlorides. 
  Sulphates. 
  

  

  f 
  Sodium. 
  C 
  Ammonium. 
  

  

  \ 
  Magnesium. 
  < 
  Magnesium. 
  

  

  f 
  Calcium. 
  (^Sodium. 
  

  

  (, 
  Potassium. 
  Hydrogen. 
  

  

  f 
  Ammonium. 
  Potassium. 
  

  

  \ 
  Hydrogen. 
  Manganese. 
  

  

  Manganese. 
  Copper. 
  

  

  Copper. 
  Zinc. 
  

  

  Zinc. 
  Cadmium. 
  

   Barium. 
  

   Strontium. 
  

   Cadmium. 
  

   Mercury. 
  

   Lead. 
  

  

  For 
  the 
  anion, 
  although 
  the 
  number 
  of 
  salts 
  investigated 
  

   is 
  hardly 
  sufficient 
  to 
  generalize, 
  yet 
  the 
  determinations 
  

   indicate 
  that 
  the 
  absorbing-power 
  is 
  in 
  the 
  following 
  order: 
  — 
  

  

  /so 
  4> 
  

  

  \NO, 
  

  

  01. 
  

  

  I, 
  

  

  Br. 
  

  

  These 
  results, 
  with 
  one 
  or 
  two 
  exceptions, 
  agree 
  with 
  those 
  

   obtained 
  by 
  previous 
  investigators 
  working 
  in 
  this 
  field. 
  

  

  Since 
  even 
  very 
  thin 
  sheets 
  of 
  metals 
  absorb 
  the 
  rays 
  

   almost 
  completely, 
  we 
  thought 
  it 
  would 
  be 
  interesting 
  to 
  

   investigate 
  the 
  effect 
  of 
  such 
  metals 
  held 
  in 
  solution 
  in 
  a 
  

   finely 
  divided 
  state. 
  With 
  this 
  idea 
  in 
  view, 
  the 
  metals 
  lead, 
  

   mercury, 
  and 
  silver 
  were 
  investigated 
  in 
  the 
  form 
  of 
  colloidal 
  

   solutions, 
  as 
  described 
  by 
  Bredig 
  (Zeit. 
  fur 
  Electrochem. 
  iv. 
  

   pp. 
  514 
  & 
  547). 
  With 
  the 
  possible 
  exception 
  of 
  mercury, 
  

   it 
  was 
  found 
  that 
  these 
  metals 
  in 
  solution 
  differed 
  very 
  

   slightly 
  from 
  water 
  in 
  their 
  power 
  of 
  absorption. 
  

  

  Owing 
  to 
  the 
  short 
  time 
  at 
  our 
  disposal, 
  only 
  a 
  few 
  of 
  the 
  

   solutions 
  which 
  we 
  had 
  hoped 
  to 
  investigate 
  have 
  been 
  

   examined, 
  and 
  the 
  determinations 
  are 
  in 
  some 
  cases 
  not 
  so 
  

   full 
  as 
  could 
  be 
  desired. 
  We 
  hope, 
  however, 
  to 
  continue 
  

   this 
  research 
  and 
  make 
  more 
  complete 
  determinations. 
  The 
  

   question 
  of 
  the 
  variation 
  of 
  absorption 
  with 
  the 
  increase 
  of 
  

   thickness 
  of 
  the 
  Jayer 
  of 
  solution 
  traversed 
  by 
  the 
  rays, 
  we 
  

   also 
  hope 
  to 
  investigate 
  by 
  a 
  somewhat 
  similar 
  but 
  improved 
  

   method 
  to 
  that 
  used. 
  

  

  In 
  conclusion 
  we 
  wish 
  to 
  express 
  our 
  thanks 
  to 
  Prof. 
  

   Rutherford 
  for 
  the 
  valuable 
  suggestions 
  which 
  he 
  offered 
  

   during 
  the 
  course 
  of 
  this 
  research. 
  

   McDonald 
  Physical 
  and 
  Chemical 
  Laboratories, 
  

   McGill 
  University, 
  Montreal. 
  July 
  15th, 
  1901. 
  

  

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