M.  0.  E.  Meyer  on  Anomalous  Dispersion  of  Light.       299 
This  equation  also  is  integrated  by  the  fuuctio  n 
v=  [A cos  (ut-(3x)+Bsm{*t-/3x)]e-v* ; 
but  a,  /3,  7  have  to  satisfy  the  equations 
«*=^(/3*-72)+2m/37, 
0 = 2^/37 -r«(/3-2-72). 
Hence  we  obtain,  for  the  quotient  of  refraction  n,  " 
-  a*"  V  +  vV  +V/^4  +  vV  ' 
so  that  according  to  this  theory  also,  if  we  again  put 
fl\  =  27T, 
there  results  for  the  quotient  of  refraction  n  an  expression, 
V+(?)'V^(?)" 
which  with  increasing  wave-length  X  becomes  itself  of  higher 
value. 
Accordingly  both  theories  explain  anomalous  dispersion  of 
light,  and  both,  too,  from  hypotheses  which  find  their  justifica- 
tion in  the  opacity  of  the  medium.  At  the  same  time  elliptic 
polarization  of  light  results  from  both  theories ;  for  the  formula 
v=  [A  cos  (ott—Px)+B  sin  (at  — 0x)]e~y* 
is  the  very  one  on  which  Cauchy  grounded  his  theory  of  metallic 
reflection. 
Our  theories,  however,  fail  us  in  one  important  point.  It 
results  from  the  values  of  7  in  both  cases  that  the  light  of  shorter 
wave-lengths  is  more  strongly  absorbed  than  that  of  greater 
wave-lengths.  Those  bodies  should  therefore  all  appear  red  by 
transmitted  light. 
Further,  on  numerical  comparison  of  the  above  formulae  with 
the  observations  of  Jamin^on  metals,  and  those  of  Christiansen 
on  Fuchsine,  we  find  no  satisfactory  agreement. 
The  preceding  theory,  therefore,  does  not  yet  completely  ex- 
haust the  subject.  But  since  it  gives  an  account  of  the  most 
important  circumstances,  I  hold  it  to  be  correctly  founded,  and 
I  hope  to  be  able  to  carry  it  further  as  soon  as  observation  shall 
have  given  us  a  more  perfect  knowledge  of  the  laws. 
Breslau,  Christmas  18/1. 
*  Ann.  de  Ch.  et  de  Ph.  3rd  scries,  vol.  xix. ;  Pogg.  Ann.  Erg.  Band  ii. 
