﻿488 
  Dr. 
  N. 
  Bohr 
  on 
  the 
  Constitution 
  

  

  For 
  the 
  permanent 
  state 
  of 
  a 
  neutral 
  hydrogen 
  atom 
  we 
  

   get 
  from 
  the 
  formula 
  (1) 
  and 
  (2) 
  in 
  § 
  2, 
  putting 
  F=l, 
  

  

  1(1). 
  a= 
  -r-^j- 
  =0-55 
  . 
  10- 
  8 
  , 
  o>= 
  A7 
  ^- 
  = 
  6-2 
  . 
  10 
  15 
  , 
  

   W= 
  -^— 
  =2-0. 
  lO" 
  11 
  , 
  

  

  These 
  values 
  are 
  of 
  the 
  order 
  of 
  magnitude 
  to 
  be 
  expected. 
  

  

  W 
  

  

  For 
  — 
  we 
  get 
  0*043, 
  which 
  corresponds 
  to 
  13 
  volts 
  ; 
  the 
  

  

  value 
  for 
  the 
  ionizing 
  potential 
  of 
  a 
  hydrogen 
  atom, 
  calcu- 
  

   lated 
  by 
  Sir 
  J. 
  J. 
  Thomson 
  from 
  experiments 
  on 
  positive 
  

   rays, 
  is 
  11 
  volts 
  *. 
  No 
  other 
  definite 
  data, 
  however, 
  are 
  

   available 
  for 
  hydrogen 
  atoms. 
  For 
  sake 
  of 
  brevity, 
  we 
  shall 
  

   in 
  the 
  following 
  denote 
  the 
  values 
  for 
  a, 
  co, 
  and 
  W 
  corre- 
  

   sponding 
  to 
  the 
  configuration 
  1(1) 
  by 
  a 
  , 
  co 
  and 
  W 
  . 
  

  

  At 
  distances 
  from 
  the 
  nucleus, 
  great 
  in 
  comparison 
  with 
  

   <2 
  , 
  the 
  system 
  1(1) 
  will 
  not 
  exert 
  sensible 
  forces 
  on 
  free 
  

   electrons. 
  Since, 
  however, 
  the 
  configuration 
  : 
  

  

  1(2) 
  a=l-33<Zfo 
  (d 
  = 
  0'56Scd 
  , 
  W 
  = 
  1-13W 
  , 
  

   corresponds 
  to 
  a 
  greater 
  value 
  for 
  W 
  than 
  the 
  configuration 
  

   1(1), 
  we 
  may 
  expect 
  that 
  a 
  hydrogen 
  atom 
  under 
  certain 
  

   conditions 
  can 
  acquire 
  a 
  negative 
  charge. 
  This 
  is 
  in 
  agree- 
  

   ment 
  with 
  experiments 
  on 
  positive 
  rays. 
  Since 
  W[l(3)] 
  is 
  

   only 
  0*54, 
  a 
  hydrogen 
  atom 
  cannot 
  be 
  expected 
  to 
  be 
  able 
  to 
  

   acquire 
  a 
  double 
  negative 
  charge. 
  

  

  N 
  = 
  2. 
  Helium. 
  

  

  As 
  shown 
  in 
  Part 
  I., 
  using 
  the 
  same 
  assumptions 
  as 
  for 
  

   hydrogen, 
  we 
  must 
  expect 
  that 
  during 
  the 
  binding 
  of 
  an 
  

   electron 
  by 
  a 
  nucleus 
  of 
  charge 
  2e, 
  a 
  spectrum 
  is 
  emitted, 
  

   •expressed 
  by 
  

  

  _ 
  2ttW 
  / 
  1 
  _1_ 
  

  

  " 
  "• 
  te'R" 
  

  

  This 
  spectrum 
  includes 
  the 
  spectrum 
  observed 
  by 
  Pickering 
  

   in 
  the 
  star 
  £ 
  Puppis 
  and 
  the 
  spectra 
  recently 
  observed 
  by 
  

   Fowler 
  in 
  experiments 
  with 
  vacuum 
  tubes 
  filled 
  with 
  a 
  

   mixture 
  of 
  hydrogen 
  and 
  helium. 
  These 
  spectra 
  are 
  generally 
  

   ascribed 
  to 
  hydrogen. 
  

  

  For 
  the 
  permanent 
  state 
  of 
  a 
  positively 
  charged 
  helium 
  

   atom, 
  we 
  get 
  

  

  2(1) 
  a 
  = 
  ±a 
  , 
  «w 
  = 
  4w 
  , 
  W 
  = 
  4W 
  . 
  _ 
  

  

  * 
  J. 
  J. 
  Thomson, 
  Phil. 
  Mag. 
  xxiv. 
  p. 
  218 
  (1912). 
  

  

  