﻿ARTICLE 
  IV 
  

  

  On 
  the 
  Longitude 
  of 
  the 
  Hall 
  of 
  the 
  American 
  Philosophical 
  Society, 
  

   deduced 
  from 
  an 
  Occultation 
  of 
  Aldebaran 
  observed 
  by 
  S. 
  C. 
  

   Walker 
  January 
  5th 
  1830. 
  Read 
  before 
  the 
  American 
  Philoso- 
  

   phical 
  Society 
  October 
  18th 
  1833. 
  

  

  On 
  the 
  evening 
  of 
  January 
  5th 
  1830, 
  1 
  observed 
  the 
  occultation 
  of 
  

   Aldebaran 
  at 
  the 
  place 
  mentioned 
  in 
  the 
  Memoir 
  on 
  the 
  Solar 
  Eclipse 
  

   of 
  February 
  12th 
  1831, 
  in 
  the 
  fourth 
  volume 
  of 
  the 
  Transactions 
  of 
  

   the 
  American 
  Philosophical 
  Society. 
  The 
  local 
  time 
  was 
  estimated 
  

   from 
  observations 
  of 
  the 
  sun 
  on 
  the 
  meridian, 
  by 
  Joseph 
  Roberts, 
  Jun. 
  

   at 
  the 
  Friends' 
  Observatory. 
  The 
  telescope 
  used 
  was 
  by 
  Dollond, 
  

   three 
  and 
  a 
  half 
  feet 
  achromatic. 
  The 
  immersion 
  and 
  emersion 
  were 
  

   both 
  visible. 
  The 
  same 
  phenomena 
  were 
  observed 
  by 
  Mr 
  Maclear 
  at 
  

   Biggleswade, 
  England 
  ; 
  by 
  Mr 
  Paine 
  at 
  Boston 
  ; 
  and 
  Mr 
  Bond 
  at 
  Dor- 
  

   chester, 
  Massachusetts. 
  The 
  immersion 
  was 
  observed 
  at 
  Cambridge, 
  

   England, 
  by 
  Professor 
  Airy 
  ; 
  and 
  at 
  Bedford, 
  England, 
  by 
  Captain 
  

   Smyth. 
  The 
  observations 
  were 
  as 
  follows 
  : 
  

  

  Occultation 
  of 
  a 
  Tauri, 
  January 
  5th 
  P.M. 
  1830. 
  

  

  Immersion. 
  

  

  Emersion. 
  

  

  Observer. 
  

  

  Place 
  of 
  Observation. 
  

  

  Latitude 
  

   North. 
  

  

  Longitude 
  from 
  

   Greenwich. 
  

  

  H. 
  51. 
  S. 
  

  

  H. 
  M. 
  s. 
  

  

  

  

  O 
  ' 
  // 
  

  

  H. 
  M. 
  s. 
  

  

  9 
  56 
  15.00 
  m.* 
  

  

  11 
  44 
  30.00 
  m. 
  

  

  Walker. 
  

  

  Philadelphia. 
  

  

  39 
  57 
  01.0 
  

  

  5 
  00 
  43.4 
  west. 
  

  

  10 
  14 
  50.50 
  m. 
  

  

  11 
  12 
  19.00 
  m. 
  

  

  Paine. 
  

  

  Boston. 
  

  

  42 
  20 
  38.0 
  

  

  4 
  44 
  15.2 
  west. 
  

  

  10 
  14 
  51.00 
  m. 
  

  

  11 
  12 
  50.00 
  m. 
  

  

  Bond. 
  

  

  Dorchester. 
  

  

  42 
  19 
  20.0 
  

  

  4 
  44 
  17.0 
  west. 
  

  

  10 
  41 
  53.18 
  s.t 
  

  

  

  Smyth. 
  

  

  Bedford, 
  Eng. 
  

  

  52 
  08 
  27.6 
  

  

  1 
  51.97 
  west. 
  

  

  10 
  42 
  44.70 
  s. 
  

  

  11 
  33 
  19.60 
  s. 
  

  

  Maclear. 
  

  

  Biggleswade, 
  Eng. 
  

  

  52 
  5 
  25.0 
  

  

  1 
  3.50 
  west. 
  

  

  10 
  44 
  07.44 
  s. 
  

  

  *■ 
  

  

  Airy. 
  

  

  Cambridge, 
  Eng. 
  

  

  52 
  12 
  10.0 
  

  

  23 
  54.00 
  east. 
  

  

  * 
  The 
  letter 
  m 
  denotes 
  mean 
  solar 
  time. 
  

  

  t 
  The 
  letter 
  s 
  denotes 
  sidereal 
  time. 
  

  

  