﻿Lea 
  — 
  Color 
  Relations 
  of 
  Atoms, 
  Ions 
  and 
  Molecules. 
  369 
  

  

  With 
  elements 
  having 
  atoms 
  always 
  colored 
  the 
  relations 
  of 
  

   the 
  transitionals 
  are 
  so 
  slight 
  that 
  I 
  hesitated 
  about 
  giving 
  them 
  

   a 
  place 
  in 
  Table 
  III 
  and 
  have 
  done 
  so 
  chiefly 
  to 
  give 
  emphasis 
  to 
  

   this 
  fact, 
  that 
  in 
  the 
  entire 
  series 
  of 
  elements 
  there 
  is 
  not 
  a 
  

   single 
  case 
  in 
  which 
  an 
  element 
  having 
  atoms 
  always 
  colorless 
  

   appears 
  in 
  the 
  regular 
  numerical 
  series 
  betioeen 
  a 
  transitional 
  

   element 
  and 
  one 
  with 
  atoms 
  always 
  colored. 
  Also 
  that 
  there 
  

   is 
  not 
  a 
  single 
  case 
  in 
  which 
  an 
  element 
  with 
  atoms 
  always 
  

   colored 
  appears 
  in 
  the 
  numerical 
  series 
  betioeen 
  a 
  transitional 
  

   element 
  and 
  one 
  having 
  colorless 
  atoms 
  only. 
  

  

  This 
  will 
  be 
  seen 
  better 
  by 
  examining 
  the 
  diagram 
  embracing 
  

   the 
  entire 
  series. 
  This 
  perfect 
  regularity 
  seems 
  to 
  justify. 
  this 
  

   new 
  method 
  of 
  classification. 
  

  

  This 
  group 
  contains 
  elements 
  whose 
  atoms 
  function 
  as 
  Jcathions 
  

   only. 
  

  

  Second 
  Division. 
  Ions 
  all 
  colored. 
  

  

  In 
  Table 
  III 
  will 
  be 
  found 
  the 
  series 
  of 
  elements 
  with 
  all 
  

   colored 
  ions 
  and 
  to 
  these 
  have 
  been 
  added 
  the 
  transitionals, 
  

   distinguished 
  by 
  being 
  printed 
  in 
  italics. 
  The 
  transitionals 
  lit 
  

   equally 
  well 
  into 
  either 
  of 
  the 
  two 
  great 
  divisions, 
  that 
  of 
  the 
  

   colorless 
  and 
  that 
  of 
  the 
  all 
  colored 
  ions, 
  with 
  this 
  difference 
  

   that 
  in 
  the 
  first 
  division 
  they 
  fit 
  into 
  the 
  center, 
  in 
  the 
  second 
  

   division 
  they 
  act 
  as 
  outliers 
  to 
  the 
  respective 
  series, 
  connecting 
  

   the 
  colored 
  with 
  the 
  colorless. 
  This 
  last 
  function 
  is 
  however 
  

   better 
  shown 
  by 
  the 
  diagram 
  at 
  the 
  end. 
  Their 
  chemical 
  rela- 
  

   tions 
  are 
  with 
  the 
  first 
  division. 
  

  

  The 
  colorless 
  elements 
  when 
  arranged 
  in 
  vertical 
  columns 
  

   form 
  groups 
  according 
  to 
  the 
  horizontal 
  lines. 
  Members 
  of 
  

   each 
  group 
  though 
  closely 
  connected 
  in 
  properties, 
  differ 
  

   widely 
  in 
  atomic 
  weights. 
  

  

  With 
  the 
  elements 
  having 
  all 
  colored 
  ions 
  the 
  case 
  is 
  very 
  

   different. 
  They 
  fall 
  into 
  four 
  series, 
  members 
  of 
  which 
  have 
  

   their 
  atomic 
  weights 
  immediately 
  following 
  each 
  other 
  in 
  

   unbroken 
  succession. 
  

  

  The 
  first 
  of 
  these 
  series 
  consists 
  of 
  the 
  metals 
  chromium 
  52, 
  

   manganese 
  55, 
  iron 
  58, 
  cobalt 
  59, 
  and 
  nickel 
  59. 
  This 
  is 
  a 
  

   very 
  well 
  marked 
  group, 
  the 
  chromates, 
  manganeses 
  and 
  fer- 
  

   rates 
  being 
  isomorphous. 
  Also 
  the 
  sesquisulphates 
  of 
  the 
  three 
  

   metals 
  replacing 
  each 
  other 
  in 
  the 
  alums. 
  

  

  Chromium 
  and 
  manganese 
  were, 
  formerly 
  always 
  placed 
  in 
  

   the 
  iron 
  group 
  until 
  the 
  exigencies 
  of 
  the 
  Periodic 
  Law 
  re- 
  

   quired 
  the 
  transfer 
  of 
  chromium 
  to 
  the 
  oxygen 
  group 
  and 
  of 
  

   manganese 
  to 
  the 
  univalent 
  halogen 
  group, 
  a 
  translocation 
  for 
  

   which 
  there 
  seems 
  no 
  sufficient 
  justification. 
  

  

  