﻿Frequency 
  and 
  Molecular 
  Number. 
  407 
  

  

  AgCl. 
  The 
  average 
  wave-length 
  of 
  the 
  residual 
  radiation* 
  

   was 
  found 
  to 
  be 
  81*5/t 
  (v 
  = 
  3*68 
  x 
  10 
  12 
  ). 
  The 
  value 
  of 
  

   (]ST 
  1 
  + 
  N 
  2 
  > 
  = 
  llx21*5xl0 
  12 
  . 
  

  

  FbCl 
  9 
  . 
  The 
  average 
  wave-length 
  . 
  in 
  this 
  case 
  * 
  was 
  

   91-0/a 
  (v=3-30 
  x 
  10 
  12 
  ), 
  giving 
  (N! 
  + 
  2N 
  2 
  >=18 
  x 
  21*2 
  x 
  10 
  12 
  . 
  

   When 
  such 
  large 
  integers 
  are 
  involved, 
  it 
  is 
  always 
  possible 
  

   to 
  find 
  an 
  integer 
  which 
  will 
  give 
  a 
  concordant 
  value 
  for 
  v 
  A 
  . 
  

  

  HgCl. 
  The 
  average 
  wave-length 
  observed* 
  was 
  98*8/t 
  

   = 
  3-04 
  x 
  10 
  12 
  ). 
  Taking 
  ^ 
  = 
  80, 
  N 
  2 
  = 
  17, 
  we 
  find 
  

  

  (N 
  2 
  + 
  N 
  2 
  >= 
  14 
  x 
  21-0 
  x 
  10 
  12 
  . 
  

  

  AgBr. 
  For 
  this 
  salt* 
  A. 
  = 
  112" 
  7fi 
  (v= 
  2*66 
  x 
  10 
  12 
  ), 
  and 
  

   (N 
  1 
  -i-N 
  3 
  )v=10|x20*8xl0 
  12 
  . 
  

  

  CaC0 
  3 
  . 
  The 
  case 
  of 
  calc 
  sparf 
  is 
  interesting 
  as 
  it 
  contains 
  

   three 
  elements, 
  whilst 
  only 
  two 
  bands 
  have 
  been 
  recorded, 
  a 
  

   strong 
  band 
  at 
  93'Oyu, 
  (y 
  = 
  3*23 
  x 
  10 
  12 
  ) 
  and 
  a 
  weaker 
  at 
  

   116*1/4 
  (v 
  = 
  2*58xl0 
  12 
  ). 
  It 
  is 
  found 
  that 
  the 
  strong 
  band 
  

   must 
  be 
  assigned 
  to 
  calcium, 
  giving 
  NV 
  = 
  3 
  x 
  21*5 
  x 
  10 
  12 
  , 
  

   the 
  weaker 
  to 
  oxygen, 
  giving 
  l^v~ 
  1 
  x 
  20*7 
  x 
  10 
  12 
  . 
  

  

  In 
  a 
  later 
  paper 
  Rubens 
  and 
  WartenbergJ 
  have 
  given 
  the 
  

   wave-lengths 
  for 
  two 
  ammonium 
  salts 
  and 
  three 
  compounds 
  

   of 
  thallium. 
  

  

  NH 
  4 
  C1. 
  The 
  observed 
  wave-lengths 
  are 
  very 
  nearly 
  the 
  

   same 
  as 
  those 
  for 
  NaOl, 
  being 
  54*0//, 
  (V 
  = 
  5*56 
  x 
  10 
  12 
  ) 
  and 
  

   4:6' 
  3 
  fi 
  = 
  6*48 
  x 
  10 
  12 
  ) 
  respectively. 
  This 
  is 
  what 
  might 
  be 
  

   expected 
  if 
  the 
  group 
  NH 
  4 
  be 
  regarded 
  as 
  a 
  compound 
  

   radicle 
  replacing 
  Xa, 
  for 
  the 
  " 
  molecular 
  number 
  " 
  of 
  am- 
  

   monium 
  (7 
  + 
  4) 
  is 
  the 
  same 
  as 
  the 
  atomic 
  number 
  of 
  

   sodium 
  (11). 
  Taking 
  the 
  first 
  line 
  as 
  associated 
  with 
  the 
  

   NH4 
  group, 
  Nv 
  = 
  3 
  x 
  204x 
  10 
  12 
  , 
  whilst 
  the 
  second 
  line 
  gives 
  

   for 
  the 
  chlorine 
  atom 
  i<v 
  = 
  5 
  x 
  22*0 
  x 
  10 
  12 
  . 
  

  

  NH^Br. 
  Here 
  again 
  two 
  wave-lengths 
  have 
  been 
  ob- 
  

   served, 
  62-3/z 
  (y 
  = 
  482 
  x 
  10 
  12 
  ) 
  and 
  55*3/* 
  (^ 
  = 
  5*42 
  x 
  10 
  12 
  ). 
  

   The 
  former 
  line 
  must 
  be 
  associated 
  with 
  bromine, 
  giving 
  

   Nv=8x21"lxl0 
  12 
  ; 
  the 
  latter 
  with 
  the 
  ammonium 
  group, 
  

   yielding 
  Nv=3 
  X 
  20*0 
  x 
  10 
  12 
  . 
  

  

  T1C1. 
  The 
  mean 
  wave-length 
  recorded 
  is 
  91*6/4 
  (v 
  = 
  3'27 
  

   x 
  10 
  12 
  ). 
  The 
  atomic 
  number 
  of 
  thallium 
  being 
  81 
  and 
  that 
  

   of 
  chlorine 
  17, 
  we 
  find 
  Ni/=15 
  x 
  21*4 
  x 
  10 
  12 
  . 
  

  

  TlBr. 
  For 
  the 
  bromide 
  the 
  mean 
  wave-length 
  is 
  117*0/1, 
  

   = 
  2*56 
  xlO 
  12 
  ). 
  In 
  this 
  case 
  we 
  find 
  Ni>=14x 
  21*2 
  x 
  10 
  12 
  . 
  

  

  Til. 
  For 
  the 
  iodide 
  the 
  mean 
  wave-length 
  is 
  151'8/t 
  

   = 
  1-98 
  x 
  10 
  l2 
  ), 
  giving 
  for 
  N* 
  the 
  value 
  13 
  x 
  20*4 
  X 
  10 
  12 
  . 
  

  

  * 
  Rubens, 
  Preuss. 
  Akad. 
  Berlin, 
  vol. 
  xxviii. 
  p. 
  513 
  (1913). 
  

  

  t 
  Eubens, 
  D. 
  P. 
  G. 
  V. 
  vol. 
  xiii. 
  p. 
  102 
  (1911). 
  

  

  % 
  Rubens 
  and 
  Wartenberg, 
  Preuss. 
  Akad. 
  Berlin, 
  p. 
  169 
  (1914). 
  

  

  2 
  F2 
  

  

  