﻿Lea 
  — 
  Color 
  Relations 
  of 
  Atoms, 
  Ions 
  and 
  Molecules. 
  361 
  

  

  indifferently, 
  by 
  that 
  of 
  their 
  atoms 
  : 
  the 
  result 
  will 
  be 
  iden- 
  

   tical. 
  

  

  The 
  color 
  of 
  the 
  atom 
  is 
  always 
  easily 
  ascertained 
  and 
  could 
  

   be 
  even 
  if 
  the 
  dissociation 
  theory 
  had 
  never 
  been 
  suggested. 
  

  

  The 
  color 
  of 
  the 
  atom 
  has 
  nothing 
  to 
  do 
  with 
  the 
  element, 
  

   for 
  it 
  we 
  must 
  go 
  to 
  the 
  salts. 
  

  

  Finding 
  that 
  the 
  chlorides, 
  bromides 
  and 
  iodides 
  of 
  the 
  

   alkaline 
  metals 
  and 
  of 
  calcium 
  strontium, 
  etc., 
  are 
  all 
  colorless 
  

   even 
  in 
  the 
  solid 
  form, 
  we 
  conclude 
  that 
  all 
  the 
  atoms 
  in 
  ques- 
  

   tion 
  are 
  colorless 
  since 
  colored 
  constituents 
  do 
  not 
  form 
  color- 
  

   less 
  compounds. 
  When 
  a 
  metal 
  combining 
  with 
  a 
  colorless 
  

   acid 
  forms 
  a 
  colored 
  compound 
  we 
  know 
  that 
  the 
  atom 
  of 
  the 
  

   metal 
  is 
  colored. 
  We 
  do 
  not 
  need 
  to 
  inquire 
  for 
  present 
  pur- 
  

   poses 
  what 
  that 
  color 
  is, 
  all 
  that 
  we 
  need 
  to 
  determine 
  is 
  

   whether 
  color 
  is 
  present 
  or 
  not. 
  In 
  fact 
  this 
  matter 
  is 
  so 
  

   simple 
  that 
  the 
  color 
  or 
  absence 
  of 
  color 
  of 
  the 
  atoms 
  and 
  the 
  

   conclusions 
  to 
  be 
  drawn 
  therefrom 
  might 
  have 
  been 
  deduced 
  

   generations 
  ago 
  from 
  facts 
  already 
  then 
  familiar. 
  

  

  From 
  this 
  we 
  can 
  obtain 
  the 
  results 
  sought 
  which 
  are, 
  first, 
  a 
  

   new 
  classification 
  of 
  the 
  elements 
  based 
  on 
  more 
  correct 
  prin- 
  

   ciples 
  than 
  those 
  previously 
  made, 
  and 
  second, 
  a 
  proof 
  that 
  the 
  

   color 
  or 
  non-color 
  of 
  an 
  element 
  is 
  a 
  function 
  of 
  its 
  atomic 
  

   weight. 
  

  

  Elementary 
  Ions. 
  

   Considering 
  the 
  elements 
  in 
  numerical 
  series, 
  we 
  find 
  : 
  

  

  1. 
  Elements 
  with 
  atomic 
  weights 
  not 
  exceeding 
  47 
  have 
  color- 
  

   less 
  ions 
  only. 
  

  

  2. 
  With 
  titanium 
  (48) 
  colored 
  ions 
  suddenly 
  commence 
  and 
  we 
  

   at 
  once 
  have 
  a 
  series 
  of 
  eight 
  unbroken, 
  viz 
  : 
  Ti 
  (48), 
  V 
  (51*2), 
  

   Cr 
  (52-4), 
  Mn 
  (54-8), 
  Fe 
  (56), 
  Co 
  (58*6), 
  Ni 
  (58*6), 
  Cu 
  (63-4). 
  

  

  3. 
  Next 
  follows 
  a 
  series 
  of 
  nine 
  metals 
  with 
  colorless 
  ions 
  only: 
  

   Zn 
  (64-9), 
  Ga 
  (69*9), 
  Ge 
  (72), 
  As 
  (74-9), 
  Se 
  (78*9), 
  Br 
  (79*8), 
  Rb 
  

   (85*2), 
  Sr 
  (87-2), 
  Yttrium 
  92-5. 
  

  

  4. 
  Then 
  six 
  metals 
  with 
  colored 
  ions: 
  Nb 
  (94), 
  Mo 
  (95*8), 
  Ru 
  

   (103-5), 
  Rh 
  (104-1), 
  Pd 
  (probably,) 
  (106-2), 
  Ag 
  (107*7). 
  

  

  5. 
  Then 
  nine 
  more 
  metals 
  with 
  colorless 
  ions: 
  Cd 
  (111*6), 
  In 
  

   (113*4), 
  Sn 
  (117-8), 
  Sb 
  (122), 
  Te 
  (125), 
  1(126-5), 
  Cs 
  (132), 
  Ba 
  

   (136*8), 
  La 
  (139). 
  

  

  6. 
  Then 
  ten 
  more 
  with 
  colored 
  ions: 
  Ce 
  (142), 
  Di 
  (145?), 
  Sm 
  

   (150), 
  Er 
  (169), 
  perhaps 
  Ta 
  (182), 
  W 
  (184), 
  Os 
  (192?), 
  Ir 
  (192*5), 
  

   Pt 
  (194), 
  Au 
  (196-2). 
  

  

  7. 
  Up 
  to 
  gold, 
  the 
  colored 
  and 
  colorless 
  ions 
  present 
  themselves 
  

   in 
  large 
  blocks 
  of 
  each 
  kind. 
  But 
  the 
  six 
  remaining 
  metals 
  are 
  

   of 
  each 
  sort 
  alternately, 
  thus 
  Hg 
  (199*8) 
  colorless; 
  Tl 
  (203-6) 
  

   colored; 
  Pb 
  (206-4) 
  colorless; 
  Bi 
  (210) 
  colored; 
  Th 
  (234?) 
  

   colorless 
  and 
  finally 
  u 
  (240) 
  colored. 
  

  

  Am. 
  Jour. 
  Sci.— 
  Third 
  Series, 
  Vol. 
  XL1X, 
  No. 
  293.— 
  May, 
  1895. 
  

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