﻿NEW 
  CHEMICAL 
  ELEMENTS 
  BLIGH 
  249 
  

  

  Although 
  superfically 
  it 
  might 
  appear 
  curious 
  that 
  a 
  discovery 
  of 
  

   note 
  should 
  be 
  made 
  independently 
  and 
  simultaneously, 
  as 
  occasionally 
  

   happens, 
  by 
  two 
  or 
  more 
  investigators, 
  actually 
  this 
  is 
  by 
  no 
  means 
  

   remarkable 
  since 
  coordinated 
  practical 
  and 
  theoretical 
  progress 
  is 
  

   likely 
  to 
  suggest 
  a 
  line 
  of 
  investigation 
  to 
  more 
  than 
  one 
  experimenter, 
  

   each 
  of 
  whom 
  would 
  refrain 
  from 
  publishing 
  a 
  report 
  of 
  his 
  work 
  until 
  

   he 
  had 
  amply 
  confirmed 
  it 
  and 
  satisfied 
  himself 
  as 
  to 
  its 
  success. 
  

   This 
  is 
  well 
  illustrated 
  by 
  subsequent 
  developments 
  in 
  the 
  present 
  

   sphere 
  of 
  thought, 
  for 
  a 
  marked 
  impetus 
  had 
  been 
  given 
  by 
  Moseley's 
  

   law 
  to 
  the 
  problem 
  of 
  isolating 
  the 
  remaining 
  elements 
  ; 
  the 
  energy 
  of 
  

   experimenters 
  had 
  been 
  conserved 
  and 
  directed 
  into 
  channels 
  offering 
  

   reasonable 
  prospect 
  of 
  success; 
  no 
  longer 
  was 
  the 
  search 
  to 
  be 
  pursued 
  

   under 
  the 
  guidance 
  of 
  only 
  meager 
  principles, 
  effort 
  was 
  not 
  to 
  be 
  

   dissipated 
  in 
  the 
  attempted 
  isolation 
  of 
  elements 
  which 
  could 
  have 
  no 
  

   existence. 
  From 
  such 
  considerations 
  is 
  the 
  gre'atness 
  of 
  Moseley's 
  

   work 
  realized. 
  

  

  Further 
  gaps 
  in 
  the 
  atomic 
  number 
  sequence 
  of 
  known 
  elements 
  

   indicated 
  two 
  undiscovered 
  analogues 
  of 
  manganese, 
  numbers 
  43 
  and 
  

   75. 
  Obviousl}'' 
  these 
  should 
  be 
  sought 
  in 
  manganese 
  minerals 
  and 
  

   could 
  be 
  expected 
  to 
  be 
  present 
  only 
  in 
  extremely 
  minute 
  quantities. 
  

   At 
  least 
  three 
  groups 
  of 
  investigators 
  are 
  known 
  from 
  published 
  results 
  

   to 
  have 
  been 
  engaged 
  in 
  this 
  search. 
  The 
  discovery 
  of 
  the 
  two 
  

   elements 
  was 
  first 
  announced 
  in 
  1925 
  by 
  three 
  German 
  chemists, 
  

   Noddack, 
  Tacke, 
  and 
  Berg 
  as 
  a 
  result 
  of 
  what 
  appeared 
  to 
  be 
  a 
  parti- 
  

   cularly 
  well-organized 
  piece 
  of 
  research, 
  using 
  platinum 
  ores 
  and 
  the 
  

   mineral 
  columbite 
  as 
  starting 
  materials. 
  A 
  curious 
  reticence 
  has, 
  

   however, 
  been 
  observed 
  by 
  these 
  same 
  authors 
  in 
  supporting 
  their 
  

   results, 
  and 
  in 
  replying 
  to 
  certain 
  criticisms 
  which 
  have 
  been 
  made. 
  

   Special 
  attention 
  is 
  therefore 
  due 
  to 
  the 
  work 
  of 
  Druce 
  and 
  Loring 
  in 
  

   England, 
  and 
  DolejSek 
  and 
  Heyrovsky 
  at 
  Prague. 
  The 
  two 
  English 
  

   workers 
  were 
  engaged 
  in 
  searching 
  for 
  possible 
  elements 
  of 
  higher 
  

   atomic 
  number 
  than 
  92, 
  by 
  an 
  examination 
  of 
  the 
  impurities 
  in 
  pure 
  and 
  

   commercial 
  manganese 
  products, 
  and 
  their 
  X-ray 
  spectrum 
  photo- 
  

   graphs 
  amply 
  demonstrate 
  and 
  confirm 
  the 
  presence 
  of 
  75. 
  The 
  

   method 
  employed 
  consisted 
  in 
  the 
  chemical 
  removal 
  of 
  contaminating 
  

   heavy 
  metals, 
  and 
  the 
  subjection 
  of 
  the 
  purified 
  product 
  to 
  X-ray 
  

   analysis. 
  The 
  lines 
  obtained 
  and 
  supported 
  by 
  previous 
  calculation 
  

   gave 
  definite 
  indication 
  of 
  75 
  (dwi-manganese) 
  and 
  in 
  addition 
  there 
  

   were 
  less 
  definite 
  or 
  less 
  well-defined 
  lines, 
  pointing 
  to 
  87 
  (eka-caesium) 
  

   the 
  missing 
  alkali 
  metal, 
  and 
  to 
  85 
  (eka-iodine) 
  the 
  missing 
  halogen; 
  

   very 
  faint 
  but 
  inconclusive 
  indication 
  of 
  93 
  was 
  also 
  obtained. 
  The 
  

   fact 
  that 
  the 
  new 
  element 
  was 
  detected 
  even 
  in 
  "pure" 
  manganese 
  

   sulphate, 
  and 
  had 
  untU 
  then 
  escaped 
  observation 
  in 
  so 
  common 
  a 
  

   material 
  points 
  to 
  the 
  extreme 
  sensitivity 
  of 
  the 
  X-ray 
  analysis 
  method 
  

   employed, 
  and 
  to 
  a 
  high 
  technique 
  in 
  measuring 
  and 
  interpreting 
  the 
  

  

  