﻿1G0 
  Dispersion 
  of 
  Magnetic 
  Rotatory 
  Power. 
  

  

  component. 
  The 
  inequality 
  of 
  these 
  two 
  maxim 
  a 
  of 
  rotation 
  

   enables 
  us 
  even 
  to 
  measure 
  the 
  dissymmetry 
  in 
  the 
  intensity 
  

   of 
  the 
  two 
  components. 
  

  

  At 
  the 
  temperature 
  of 
  liquid 
  or 
  solid 
  hydrogen 
  the 
  dis- 
  

   symmetry 
  is 
  sometimes 
  such 
  that 
  the 
  direction 
  of 
  the 
  pheno- 
  

   menon 
  is 
  the 
  same 
  as 
  if 
  there 
  existed 
  only 
  one 
  of 
  the 
  circular 
  

   components, 
  corresponding 
  to 
  vibrations 
  in 
  one 
  direction 
  

   alone 
  ; 
  we 
  then 
  obtain 
  rotations 
  in 
  opposite 
  senses 
  at 
  the 
  two 
  

   edges 
  of 
  the 
  hand. 
  This 
  result 
  again 
  is 
  a 
  consequence 
  of 
  the 
  

   simultaneous 
  effects 
  of 
  anomalous 
  dispersion 
  and 
  of 
  the 
  

   modifications 
  undergone 
  by 
  the 
  band 
  under 
  the 
  influence 
  of 
  

   the 
  field 
  : 
  it 
  is 
  in 
  good 
  agreement 
  with 
  the 
  theory 
  based 
  on 
  

   the 
  Hall 
  effect 
  ; 
  but 
  we 
  must 
  take 
  into 
  account 
  the 
  new 
  fact 
  

   that 
  no 
  theory 
  can 
  yet 
  explain 
  the 
  dissymmetry 
  of 
  intensity 
  

   of 
  the 
  two 
  components 
  corresponding 
  to 
  opposite 
  circular 
  

   vibrations. 
  

  

  Lastly, 
  in 
  a 
  general 
  manner, 
  the 
  constriction 
  of 
  the 
  bands 
  

   which 
  takes 
  place 
  under 
  the 
  influence 
  of 
  cooling 
  enables 
  us 
  

   to 
  separate 
  many 
  complex 
  groups 
  into 
  their 
  elements 
  and 
  to 
  

   explain 
  certain 
  effects. 
  Thus, 
  to 
  return 
  to 
  an 
  example 
  cited 
  

   above, 
  the 
  band 
  577 
  fMfj, 
  of 
  tysonite, 
  which 
  gives 
  opposite 
  

   rotations 
  at 
  the 
  two 
  edges, 
  appears 
  double 
  at 
  very 
  low 
  

   temperatures 
  ; 
  and 
  it 
  is 
  constituted 
  of 
  a 
  band 
  of 
  positive 
  and 
  

   one 
  of 
  negative 
  electrons 
  in 
  juxtaposition 
  ; 
  the 
  effects 
  of 
  

   these 
  are 
  superposed. 
  

  

  The 
  variation 
  of 
  magnetic 
  rotatory 
  power 
  near 
  an 
  absorption- 
  

   band 
  seems 
  then 
  to 
  be 
  related 
  to 
  the 
  hypothesis 
  of 
  the 
  Hall 
  

   effect, 
  according 
  to 
  which 
  they 
  are 
  a 
  consequence 
  of 
  the 
  

   simultaneous 
  action 
  of 
  anomalous 
  dispersion 
  and 
  of 
  the 
  

   change 
  of 
  period 
  of 
  the 
  absorbing 
  electrons 
  in 
  a 
  magnetic 
  

   field. 
  

  

  It 
  is 
  not 
  proved 
  as 
  a 
  matter 
  of 
  fact 
  that 
  a 
  simple 
  band 
  in 
  

   any 
  case 
  gives 
  rise 
  to 
  the 
  ])henomena 
  indicated 
  by 
  the 
  molecular 
  

   current 
  theory. 
  

  

  The 
  single 
  effect 
  which 
  it 
  might 
  perhaps 
  be 
  possible 
  to 
  

   bring 
  into 
  relation 
  with 
  the 
  latter 
  theory 
  is 
  the 
  increase 
  of 
  

   the 
  magnetic 
  rotatory 
  power 
  of 
  paramagnetic 
  crystals 
  when 
  

   we 
  lower 
  the 
  temperature*. 
  

  

  I 
  found 
  that 
  this 
  rotatory 
  power 
  is 
  very 
  nearly 
  in 
  inverse 
  

   proportion 
  to 
  the 
  absolute 
  temperature. 
  But 
  one 
  is 
  not 
  

   concerned 
  in 
  this 
  phenomenon 
  with 
  the 
  perturbations 
  pro- 
  

   duced 
  by 
  bands 
  of 
  absorption. 
  

  

  In 
  conclusion, 
  I 
  will 
  add 
  a 
  few 
  remarks 
  relative 
  to 
  biaxial 
  

  

  * 
  Comptes 
  Rendus, 
  L'-i 
  May, 
  L907 
  : 
  Le 
  Radium, 
  v. 
  No. 
  1. 
  p. 
  12 
  (1908). 
  

   Jean 
  Jiccquerel 
  and 
  Kamerlinirh 
  Oniies, 
  ho. 
  vi(. 
  

  

  