﻿F. 
  H. 
  Bigelow 
  — 
  Solar 
  Corona. 
  

  

  For 
  giving 
  the 
  proper 
  position 
  to 
  the 
  model 
  for 
  any 
  eclipse 
  

   this 
  simple 
  device 
  is 
  adopted. 
  The 
  circular 
  stand 
  is 
  placed 
  on 
  

   a 
  sheet 
  of 
  card 
  board 
  and 
  two 
  concentric 
  circles 
  are 
  drawn 
  

   upon 
  it 
  surrounding 
  the 
  base 
  of 
  the 
  stand. 
  On 
  the 
  inner 
  one 
  

   the 
  figures 
  represent 
  the 
  direction 
  from 
  the 
  center 
  towards 
  the 
  

   earth, 
  equal 
  to 
  the 
  sun's 
  longitude 
  of 
  date 
  + 
  180°. 
  A 
  mark 
  on 
  

   the 
  stand, 
  drawn 
  by 
  regarding 
  the 
  inclination 
  of 
  the 
  axis 
  at 
  

   7° 
  15', 
  and 
  representing 
  the 
  position 
  of 
  the 
  node, 
  is 
  placed 
  at 
  

   the 
  reading 
  71° 
  on 
  the 
  circle 
  just 
  described. 
  For 
  any 
  eclipse 
  

   turn 
  the 
  card 
  board 
  with 
  the 
  stand 
  upon 
  it 
  about 
  so 
  that 
  the 
  

   reading 
  (O-|-180 
  o 
  ) 
  is 
  between 
  the 
  observer 
  and 
  the 
  center. 
  

   Furthermore 
  adopting 
  the 
  data 
  given 
  above 
  for 
  the 
  epoch 
  

   1878 
  '0 
  as 
  the 
  elements 
  of 
  predicting 
  the 
  position 
  of 
  the 
  poles 
  

   of 
  the 
  corona, 
  a 
  table 
  has 
  been 
  constructed 
  for 
  a 
  series 
  of 
  cor- 
  

   onas 
  from 
  1857 
  to 
  1893. 
  On 
  the 
  second 
  circle 
  the 
  0° 
  reading 
  

   begins 
  at 
  74° 
  of 
  the 
  first 
  circle, 
  and 
  it 
  is 
  necessary 
  to 
  rotate 
  the 
  

   ball 
  so 
  that 
  the 
  North 
  pole 
  of 
  the 
  corona 
  shall 
  point 
  to 
  the 
  

   reading 
  that 
  was 
  computed. 
  The 
  observer 
  will 
  then 
  see 
  the 
  

   model 
  in 
  the 
  position 
  of 
  the 
  corona 
  of 
  the 
  sun, 
  if 
  the 
  eye 
  is 
  

   placed 
  on 
  the 
  same 
  level 
  plane 
  as 
  that 
  passing 
  through 
  the 
  cen- 
  

   ter 
  of 
  the 
  ball. 
  The 
  following 
  table 
  gives 
  the 
  two 
  readings 
  

   necessaiw 
  for 
  setting 
  the 
  model. 
  They 
  are 
  computed 
  for 
  the 
  

   Greenwich 
  mean 
  time 
  of 
  conjunction 
  of 
  the 
  Sun 
  and 
  Moon 
  

   for 
  the 
  several 
  eclipses 
  as 
  given 
  by 
  the 
  Xautical 
  Almanac. 
  

   Observations 
  made 
  at 
  any 
  other 
  time 
  can 
  be 
  readily 
  corrected. 
  

  

  Table 
  of 
  Coordinates 
  for 
  setting 
  the 
  Model 
  of 
  fhe 
  Corona. 
  

  

  Date 
  of 
  Eclipse. 
  

  

  Long. 
  

   Eartn. 
  

  

  Long. 
  

   Corona. 
  

  

  Date 
  of 
  Eclipse. 
  

  

  Long. 
  

   Earth. 
  

  

  Long. 
  

   Corona. 
  

  

  1857-23254 
  G. 
  M. 
  T. 
  

  

  185° 
  

  

  294 
  -4 
  D 
  

  

  1876-71441 
  G. 
  M. 
  T. 
  

  

  355° 
  

  

  147-7° 
  

  

  1858-68616 
  " 
  

  

  344 
  

  

  67-3 
  

  

  1878 
  57741 
  

  

  306 
  

  

  84-4 
  

  

  186054647 
  " 
  

  

  295 
  

  

  3511 
  

  

  1880-02999 
  " 
  

  

  111 
  

  

  212-4 
  

  

  1862-00094 
  " 
  

  

  99 
  

  

  128-2 
  

  

  1882-37597 
  

  

  236 
  

  

  305 
  9 
  

  

  186434503 
  " 
  

  

  225 
  

  

  248-6 
  

  

  188334747 
  " 
  • 
  

  

  226 
  

  

  2861 
  

  

  186531645 
  

  

  215 
  

  

  1925 
  

  

  1885-68965 
  

  

  346 
  

  

  1-4 
  

  

  1867-66140 
  " 
  

  

  336 
  

  

  281-0 
  

  

  1886-66132 
  

  

  336 
  

  

  342-4 
  

  

  1868-63032 
  " 
  

  

  325 
  

  

  243-8 
  

  

  1887-59106 
  " 
  

  

  311 
  

  

  122-4' 
  

  

  1869 
  60209 
  " 
  

  

  315 
  

  

  230-4 
  

  

  1889-00517 
  

  

  101 
  

  

  65-7 
  

  

  1871-94778 
  " 
  

  

  80 
  

  

  3225 
  

  

  1889-97616 
  " 
  

  

  91 
  

  

  43 
  5 
  

  

  187129174 
  

  

  206 
  

  

  46-3 
  

  

  1892 
  32003 
  

  

  216 
  

  

  126 
  9 
  

  

  1875-26358 
  

  

  196 
  

  

  30-2 
  

  

  1893-29187 
  

  

  207 
  

  

  108 
  8 
  

  

  Three 
  cases 
  are 
  presented 
  for 
  comparison. 
  Figures 
  1, 
  3, 
  5, 
  

   show 
  the 
  model 
  placed 
  in 
  three 
  positions, 
  corresponding 
  to 
  the 
  

   eclipses 
  of 
  Jan. 
  1, 
  1889, 
  August 
  29, 
  1886, 
  and 
  July 
  29, 
  1878. 
  

   Figures 
  2, 
  4, 
  6, 
  represent 
  these 
  coronas, 
  as 
  drawn 
  from 
  the 
  

   photographs. 
  

  

  