﻿Lea 
  — 
  Color 
  Relations 
  of 
  Atoms, 
  Ions 
  and 
  Molecules. 
  363 
  

  

  The 
  Law 
  of 
  Color. 
  

  

  In 
  the 
  first 
  part 
  of 
  this 
  paper 
  has 
  been 
  developed 
  the 
  con- 
  

   ception 
  that 
  the 
  color 
  of 
  the 
  atom 
  is 
  all-important 
  whilst 
  that 
  

   of 
  the 
  element 
  has 
  little 
  significance. 
  That 
  there 
  exists 
  no 
  

   relation 
  whatever 
  between 
  the 
  two, 
  so 
  that 
  the 
  color 
  of 
  the 
  

   atom 
  can 
  never 
  be 
  deduced 
  from 
  that 
  of 
  the 
  element. 
  But 
  the 
  

   color 
  of 
  the 
  ion 
  can 
  always 
  be 
  found 
  by 
  certain 
  criteria 
  which 
  

   have 
  been 
  given 
  and 
  it 
  has 
  been 
  shown 
  that 
  the 
  color 
  of 
  the 
  

   atom 
  is 
  the 
  same 
  as 
  that 
  of 
  the 
  ion. 
  Both 
  may 
  or 
  may 
  not 
  

   change 
  with 
  changes 
  of 
  valency. 
  

  

  Several 
  interesting 
  results 
  follow 
  from 
  this 
  conception. 
  It 
  

   appears 
  that 
  we 
  must 
  reject 
  the 
  well-known 
  Periodic 
  Law 
  as 
  

   being 
  based 
  on 
  erroneous 
  principles. 
  

  

  Another 
  result 
  is 
  the 
  establishment 
  of 
  the 
  Law 
  of 
  Color, 
  

   which 
  may 
  be 
  formulated 
  as 
  follows 
  : 
  

  

  No 
  element 
  having 
  ions 
  colored 
  at 
  all 
  valencies 
  can 
  helong 
  

   to 
  the 
  same 
  natural 
  group 
  with 
  elements 
  having 
  colorless 
  ions 
  

   only. 
  

  

  This 
  law 
  is 
  rigorous 
  and 
  fundamental 
  : 
  rigorous 
  because 
  it 
  

   admits 
  of 
  no 
  exception 
  ; 
  fundamental 
  because 
  it 
  divides 
  ele- 
  

   ments 
  into 
  two 
  chief 
  divisions 
  with 
  strongly 
  marked 
  differ- 
  

   ences. 
  

  

  They 
  even 
  diifer 
  in 
  the 
  method 
  of 
  classification 
  which 
  they 
  

   require. 
  The 
  colorless 
  elements 
  fall 
  into 
  groups 
  with 
  atomic 
  

   weights 
  widely 
  differing, 
  the 
  elements 
  with 
  colored 
  ions 
  tend 
  

   to 
  fall 
  into 
  series 
  with 
  atomic 
  weights 
  immediately 
  following 
  

   each 
  other. 
  

  

  The 
  periodic 
  Law 
  which 
  we 
  owe 
  to 
  Newlands, 
  Mendeleef 
  

   and 
  Lothair 
  Meyer, 
  beautiful 
  and 
  fruitful 
  as 
  it 
  has 
  proved, 
  

   contains 
  nevertheless 
  defects 
  of 
  a 
  serious 
  character 
  ; 
  some 
  

   already 
  recognized, 
  and 
  condoned 
  only 
  in 
  view 
  of 
  its 
  great 
  

   merits 
  and 
  services. 
  

  

  For 
  the 
  three 
  metals 
  copper, 
  silver 
  and 
  gold 
  the 
  periodic 
  

   law 
  affords 
  absolutely 
  no 
  place. 
  The 
  numbers 
  of 
  their 
  atomic 
  

   weights 
  made 
  it 
  necessary 
  to 
  insert 
  them 
  amongst 
  the 
  metals 
  

   of 
  the 
  alkalies, 
  where 
  they 
  are 
  thoroughly 
  out 
  of 
  place. 
  The 
  

   fact 
  that 
  there 
  was 
  no 
  choice 
  but 
  to 
  put 
  them 
  there 
  is 
  in 
  

   itself 
  a 
  proof 
  that 
  the 
  law 
  of 
  octaves 
  rests 
  on 
  a 
  false 
  basis. 
  

  

  A 
  very 
  grave 
  fault 
  is 
  the 
  complete 
  exclusion 
  of 
  hydrogen. 
  

   A 
  system 
  must 
  be 
  defective 
  which 
  finds 
  a 
  place 
  for 
  one 
  ele- 
  

   ment 
  of 
  water 
  and 
  none 
  for 
  the 
  other, 
  and 
  which 
  totally 
  

   excludes 
  the 
  most 
  important 
  of 
  all 
  the 
  kathions. 
  This 
  exclu- 
  

   sion 
  is 
  so 
  complete 
  that 
  in 
  the 
  published 
  tables 
  of 
  the 
  periodic 
  

   law 
  the 
  symbol 
  for 
  hydrogen 
  does 
  not 
  generally 
  appear.* 
  

  

  * 
  Cf. 
  Modernen 
  Theorien, 
  pp. 
  140, 
  143. 
  Ostwald, 
  Lehrbuch 
  2d 
  German 
  edi- 
  

   tion 
  pp. 
  134, 
  135. 
  Ramsay's 
  Chem. 
  pp. 
  628, 
  629. 
  

  

  