﻿Radioactivity 
  of 
  Potassium 
  and 
  other 
  Alkali 
  Metals. 
  385 
  

  

  and 
  all 
  three 
  salts 
  were 
  found 
  to 
  possess 
  to 
  within 
  one 
  per 
  

   cent, 
  the 
  same 
  activity. 
  On 
  another 
  occasion, 
  a 
  sample 
  of 
  

   potassium 
  cyanide 
  obtained 
  from 
  Kahlbaum 
  was 
  compared 
  

   with 
  a 
  specimen 
  of 
  the 
  same 
  salt 
  manufactured 
  by 
  Mercks, 
  

   and 
  was 
  found 
  to 
  display 
  an 
  activity 
  more 
  than 
  four 
  times 
  as 
  

   intense 
  as 
  that 
  of 
  the 
  latter. 
  

  

  In 
  this 
  connexion 
  the 
  extremely 
  low 
  value 
  found 
  for 
  the 
  

   activity 
  of 
  the 
  sample 
  of 
  potassium 
  sulphite 
  tested 
  also 
  

   merits 
  emphasis. 
  Potassium 
  metal 
  itself, 
  it 
  will 
  be 
  seen, 
  

   exhibited 
  a 
  marked 
  activity, 
  but 
  the 
  value 
  assigned 
  to 
  it, 
  

   however, 
  is 
  not 
  to 
  be 
  taken 
  as 
  comparable 
  with 
  the 
  values 
  

   recorded 
  for 
  the 
  different 
  salts 
  of 
  this 
  metal, 
  inasmuch 
  as 
  it 
  

   was 
  not 
  possible 
  to 
  prepare 
  layers 
  of 
  the 
  metal 
  for 
  examination 
  

   as 
  regular 
  and 
  uniform 
  as 
  those 
  of 
  the 
  salts. 
  

  

  From 
  a 
  consideration 
  of 
  all 
  the 
  results 
  given 
  in 
  Table 
  V. 
  

   it 
  would 
  appear 
  : 
  — 
  * 
  

  

  First. 
  That 
  the 
  values 
  of 
  -^ 
  x 
  10 
  2 
  found 
  for 
  the 
  different 
  

  

  potassium 
  salts 
  exhibited 
  extremely 
  wide 
  variations, 
  and 
  that 
  

   if 
  the 
  purity 
  of 
  the 
  salts 
  was 
  assumed, 
  these 
  were 
  such 
  as 
  to 
  

   practically 
  preclude 
  the 
  view 
  that 
  the 
  activity 
  of 
  the 
  salts 
  

   was 
  due 
  to 
  a 
  normal 
  atomic 
  property 
  of 
  potassium. 
  

  

  Second. 
  That 
  while 
  one 
  sample 
  of 
  sodium 
  chloride 
  in 
  the 
  

   form 
  of 
  rock-salt 
  showed 
  an 
  activity 
  comparable 
  with 
  that 
  

   exhibited 
  by 
  a 
  number 
  of 
  potassium 
  salts, 
  several 
  other 
  

   samples 
  of 
  rock-salt 
  were 
  found 
  to 
  be 
  quite 
  inactive. 
  Metallic 
  

   sodium, 
  too, 
  and 
  also 
  a 
  specimen 
  of 
  sodium 
  carbonate, 
  when 
  

   examined, 
  did 
  not 
  exhibit 
  the 
  slightest 
  trace 
  of 
  radioactivity, 
  

   and 
  consequently 
  it 
  would 
  appear 
  that 
  the 
  activity 
  observed 
  

   in 
  the 
  single 
  instance 
  of 
  sodium 
  chloride 
  mentioned 
  was 
  due 
  

   to 
  the 
  presence 
  in 
  this 
  salt 
  of 
  a 
  trace 
  of 
  an 
  active 
  impurity. 
  

   The 
  low 
  values 
  obtained 
  by 
  Elster 
  and 
  Geitel 
  in 
  their 
  

   measurements 
  on 
  the 
  conductivity 
  of 
  air 
  in 
  a 
  salt 
  mine 
  would 
  

   also 
  support 
  this 
  view. 
  

  

  Third. 
  That 
  with 
  the 
  exception 
  of 
  ammonium 
  chloride 
  

   which 
  emitted 
  a 
  feeble 
  activity, 
  none 
  of 
  the 
  lithium 
  and 
  

   ammonium 
  salts 
  showed 
  the 
  slightest 
  trace 
  of 
  radioactivity, 
  

   and 
  that 
  a 
  sample 
  of 
  rubidium 
  alum 
  exhibited 
  an 
  activity 
  

   which 
  was 
  extremely 
  small, 
  and 
  a 
  specimen 
  of 
  caesium 
  

   chloride 
  one 
  which 
  was 
  only 
  just 
  measurable. 
  

  

  Y. 
  Activities 
  of 
  Different 
  Samples 
  of 
  Potassium 
  Cyanide. 
  

  

  From 
  suggestions 
  received 
  by 
  the 
  writers 
  from 
  a 
  number 
  

   of 
  sources 
  it 
  seemed 
  desirable 
  to 
  make 
  a 
  closer 
  examination 
  

   of 
  the 
  activities 
  of 
  different 
  specimens 
  of 
  potassium 
  cyanide; 
  

   and 
  with 
  the 
  object 
  of 
  doing 
  this 
  five 
  different 
  samples 
  were 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  16. 
  No. 
  93. 
  Sept. 
  1908. 
  2 
  D 
  

  

  