﻿F. 
  II. 
  Bigeloio 
  — 
  Solar 
  Corona. 
  3 
  

  

  less 
  than 
  two 
  degrees, 
  and 
  this 
  had 
  but 
  little 
  influence 
  upon 
  the 
  

   traces 
  of 
  the 
  curves 
  themselves. 
  The 
  second 
  point, 
  namely, 
  

   that 
  the 
  center 
  of 
  polarization 
  coincided 
  with 
  the 
  center 
  of 
  the 
  

   sun 
  was 
  more 
  inaccurate, 
  and 
  this 
  was 
  shown 
  by 
  the 
  fact 
  that 
  

   in 
  computing 
  the 
  angle 
  through 
  which 
  the 
  plane 
  containing 
  

   a 
  given 
  ray 
  must 
  be 
  turned 
  about 
  the 
  axis 
  of 
  polarization 
  to 
  

   produce 
  the 
  curve 
  as 
  it 
  appeared 
  on 
  the 
  photograph, 
  it 
  was 
  

   found 
  that 
  this 
  angle 
  progressed 
  in 
  value 
  for 
  points 
  of 
  the 
  

   curve, 
  as 
  we 
  passed 
  from 
  the 
  surface 
  of 
  the 
  sun 
  to 
  its 
  extrem- 
  

   ity. 
  This 
  angle 
  was 
  however 
  checked 
  at 
  the 
  following 
  step 
  in 
  

   the 
  computation, 
  by 
  which 
  each 
  measured 
  point 
  on 
  the 
  ray 
  

   gives 
  the 
  polar 
  distance 
  o 
  at 
  which 
  the 
  ray 
  under 
  discussion 
  

   springs 
  from 
  the 
  surface 
  of 
  the 
  sun. 
  We 
  propose 
  to 
  rediscuss 
  

   this 
  question, 
  in 
  a 
  second 
  approximation, 
  at 
  some 
  future 
  time. 
  

   The 
  upshot 
  of 
  the 
  whole 
  matter 
  is 
  that 
  of 
  all 
  the 
  curves 
  that 
  

   theoretically 
  exist 
  in 
  space, 
  as 
  surrounding 
  a 
  polarized 
  sphere, 
  

   only 
  such 
  occur 
  in 
  the 
  corona 
  as 
  spring 
  from 
  a 
  belt 
  lying 
  

   generally 
  between 
  the 
  parallels 
  of 
  coronal 
  polar 
  distance 
  25° 
  

   to 
  40° 
  in 
  each 
  hemisphere 
  of 
  the 
  sun. 
  I 
  subjoin 
  a 
  summary 
  

   of 
  my 
  result 
  for 
  the 
  three 
  coronas. 
  Each 
  value 
  of 
  o 
  , 
  the 
  

   polar 
  distance 
  of 
  the 
  base 
  of 
  the 
  ray 
  on 
  the 
  solar 
  photosphere, 
  

   is 
  the 
  mean 
  of 
  generally 
  three, 
  sometimes 
  four 
  or 
  five 
  points 
  

   measured 
  on 
  the 
  ray. 
  The 
  mutual 
  agreement 
  is 
  substantial 
  

   and 
  convincing. 
  

  

  Angular 
  Distance 
  from 
  the 
  Coronal 
  Pole 
  of 
  the 
  Base 
  of 
  the 
  Rays. 
  

  

  Corona 
  of 
  July 
  29, 
  1878. 
  

  

  Eay. 
  N. 
  E. 
  N". 
  W. 
  S. 
  W. 
  S. 
  E. 
  

  

  1 
  29° 
  42' 
  31° 
  8' 
  32° 
  41' 
  31° 
  31' 
  

  

  2 
  28 
  32 
  27 
  18 
  30 
  30 
  31 
  31 
  

  

  3 
  30 
  52 
  34 
  40 
  32 
  25 
  33 
  44 
  

  

  4 
  31 
  45 
  33 
  36 
  30 
  38 
  33 
  8 
  

  

  5 
  32 
  50 
  33 
  37 
  34 
  21 
  33 
  55 
  

  

  6 
  33 
  46 
  41 
  34 
  36 
  16 
  34 
  8 
  

  

  7 
  35 
  53 
  .. 
  .. 
  38 
  58 
  35 
  11 
  

  

  8 
  41 
  41 
  .. 
  _. 
  40 
  54 
  38 
  18 
  

  

  Mean 
  

  

  33 
  56 
  33 
  49 
  

  

  Ray. 
  

  

  Corona 
  of 
  Jan. 
  1, 
  1889. 
  

   N. 
  W. 
  S. 
  W. 
  

   30° 
  33' 
  31° 
  50' 
  

  

  2 
  

  

  28 
  

  

  27 
  

  

  29 
  

  

  31 
  

  

  29 
  

  

  49 
  

  

  27 
  

  

  23 
  

  

  3 
  

  

  24 
  

  

  39 
  

  

  32 
  

  

  5 
  

  

  31 
  

  

  33 
  

  

  30 
  

  

  00 
  

  

  4 
  

  

  18 
  

  

  1 
  

  

  32 
  

  

  18 
  

  

  30 
  

  

  11 
  

  

  32 
  

  

  16 
  

  

  5 
  

  

  31 
  

  

  13 
  

  

  33 
  

  

  12 
  

  

  34 
  

  

  21 
  

  

  33 
  

  

  21 
  

  

  6 
  

  

  37 
  

  

  49 
  

  

  32 
  

  

  45 
  

  

  29 
  

  

  20 
  

  

  33 
  

  

  48 
  

  

  7 
  

  

  42 
  

  

  51 
  

  

  

  

  36 
  

  

  43 
  

  

  34 
  

  

  26 
  

  

  8 
  

  

  -- 
  

  

  -- 
  

  

  -- 
  

  

  -- 
  

  

  -- 
  

  

  " 
  

  

  36 
  

  

  52 
  

  

  