﻿Atomic 
  Weight 
  of 
  Radimn 
  from 
  Spectroscopic 
  Data, 
  413 
  

  

  in 
  magnesmm 
  : 
  and 
  it 
  is 
  not 
  possible 
  that 
  we 
  have 
  to 
  deal 
  

   with 
  an 
  accidental 
  coincidence. 
  

  

  An 
  absolutely 
  straight 
  line 
  cannot 
  be 
  drawn 
  through 
  more 
  

   than 
  two 
  of 
  these 
  points 
  in 
  the 
  diagram. 
  The 
  six 
  possible 
  

   lines 
  give 
  the 
  following 
  values 
  for 
  the 
  atomic 
  weights: 
  — 
  

  

  

  Mg. 
  

  

  Ca. 
  

  

  Sr. 
  

  

  Ba. 
  

  

  Ea. 
  

  

  MgCa 
  line".. 
  

  

  . 
  [24-32] 
  

  

  [40-09] 
  

  

  82-30 
  

  

  125-28 
  

  

  226-83 
  

  

  MgSr 
  line 
  .. 
  

  

  . 
  [24-32] 
  

  

  4113 
  

  

  [87-62] 
  

  

  136-30 
  

  

  254-43 
  

  

  MgBaline 
  .. 
  

  

  . 
  [24-32] 
  

  

  41-23 
  

  

  88-13 
  

  

  [137-37] 
  

  

  257-14 
  

  

  CaSr 
  line 
  .. 
  

  

  . 
  23-28 
  

  

  [40-09] 
  

  

  [87-62] 
  

  

  138-36 
  

  

  263-81 
  

  

  CaBa 
  line 
  .. 
  

  

  . 
  23-36 
  

  

  [40-09] 
  

  

  87-22 
  

  

  [137-37] 
  

  

  260-93 
  

  

  SrBa 
  line 
  .. 
  

  

  . 
  23-78 
  

  

  40-89 
  

  

  [87-62] 
  

  

  [137-37] 
  

  

  259-26 
  

  

  The 
  straight 
  line 
  chosen 
  by 
  Runge 
  and 
  Precht 
  corresponding 
  

   to 
  the 
  formula 
  

  

  log 
  at. 
  wt.=0-2005 
  + 
  0-5997 
  log 
  x 
  

  

  gives 
  the 
  following 
  values 
  : 
  — 
  

  

  Mg 
  23-84 
  instead 
  of 
  24-32 
  

  

  Ca 
  40-6 
  „ 
  40-09 
  

  

  Sr 
  87-5 
  „ 
  87-62 
  

  

  Ba 
  136-9 
  „ 
  137-37 
  

  

  and 
  for 
  Ra 
  257-8. 
  

  

  The 
  following 
  formula 
  represents 
  a 
  line 
  of 
  slight 
  curvature 
  

   which 
  passes 
  almost 
  exactly 
  through 
  Mg, 
  Ca, 
  Sr, 
  and 
  Ba, 
  and 
  

   which 
  gives 
  22'6'& 
  for 
  the 
  atomic 
  weight 
  of 
  Radium 
  : 
  — 
  

  

  log 
  at. 
  wt. 
  = 
  1-886242 
  + 
  -623179 
  (log 
  .^-2-813121) 
  

  

  --080391 
  (log 
  .2^-2-813121)^ 
  

  

  --0374175(log.2j~2-813121)S 
  

   giving 
  

  

  Mg 
  24-32, 
  

  

  Ca 
  40-08, 
  

  

  Sr 
  87-62, 
  

  

  Ba 
  137-41, 
  

  

  Ra 
  226-56. 
  

  

  Such 
  a 
  formula 
  can 
  only 
  be 
  considered 
  as 
  an 
  interpolation- 
  

   formula 
  ; 
  but 
  it 
  seems 
  desirable 
  to 
  place 
  it 
  upon 
  record, 
  

   since 
  it 
  shows 
  that 
  the 
  spectroscopic 
  data 
  are 
  consistent 
  with 
  

   the 
  atomic 
  weight 
  obtained 
  for 
  Radium 
  by 
  chemical 
  methods. 
  

  

  I 
  am 
  indebted 
  to 
  my 
  friend, 
  Rev. 
  P. 
  H. 
  Jones, 
  M.A., 
  R.N., 
  

   for 
  assistance 
  in 
  calculatinor 
  this 
  formuhi. 
  

  

  