﻿Date. 
  Obs'r. 
  

  

  Latitude. 
  

  

  1883*8 
  T. 
  43° 
  4' 
  

  

  36 
  // 
  '45 
  z 
  fc0 
  // 
  '14 
  

  

  84-5 
  H. 
  and 
  C. 
  

  

  36-49 
  zh 
  0-04 
  

  

  85-5 
  H. 
  C. 
  andU. 
  

  

  36-54 
  dz 
  0-04 
  

  

  87-2 
  U. 
  and 
  L. 
  

  

  36-61 
  ± 
  0*04 
  

  

  88-6 
  B. 
  

  

  36-76 
  zh 
  0-03 
  

  

  89-6 
  B. 
  and 
  E. 
  

  

  36-81 
  ± 
  0-03 
  

  

  90-2 
  B. 
  and 
  E. 
  

  

  36-74 
  i 
  0-06 
  

  

  + 
  0' 
  

  

  '•06 
  

  

  + 
  

  

  •05 
  

  

  + 
  

  

  •04 
  

  

  + 
  

  

  •11 
  

  

  + 
  

  

  •05 
  

  

  — 
  

  

  •11 
  

  

  G. 
  C. 
  Comstock 
  — 
  The 
  Secular 
  'Variation 
  of 
  Latitudes. 
  475 
  

  

  determined 
  from 
  observations 
  of 
  fundamental 
  stars 
  made 
  with 
  

   the 
  Repsold 
  meridian 
  circle. 
  In 
  the 
  reduction 
  of 
  the 
  observa- 
  

   tions 
  the 
  latitude 
  is 
  made 
  to 
  depend 
  upon 
  the 
  declinations 
  of 
  

   these 
  stars 
  as 
  given 
  in 
  the 
  Berliner 
  Jahrbuch 
  and 
  observations 
  

   on 
  opposite 
  sides 
  of 
  the 
  zenith 
  were 
  combined 
  in 
  such 
  a 
  way 
  

   as 
  to 
  eliminate 
  the 
  errors 
  of 
  the 
  instrument 
  and 
  of 
  the 
  refrac- 
  

   tion 
  tables. 
  The 
  results 
  of 
  separate 
  years 
  are 
  given 
  in 
  the 
  fol- 
  

   lowing 
  table 
  : 
  

  

  Meridian 
  circle 
  latitudes 
  of 
  Madison. 
  

  

  Lat. 
  1890-0* 
  

   36 
  /; 
  '70 
  

   36.72 
  

   36-72 
  

   36-72 
  

   36-82 
  

   36-83 
  

   36-73 
  

  

  It 
  should 
  be 
  said 
  in 
  regard 
  to 
  these 
  values 
  that 
  the 
  observa- 
  

   tions 
  of 
  each 
  year 
  except 
  the 
  first 
  and 
  last 
  are 
  distributed 
  

   through 
  the 
  whole 
  circuit 
  of 
  twenty-four 
  hours 
  of 
  right 
  ascen- 
  

   sion 
  and 
  are 
  sufficiently 
  numerous 
  to 
  furnish 
  a 
  good 
  represen- 
  

   tation 
  of 
  the 
  system 
  of 
  declinations 
  adopted 
  as 
  fundamental. 
  

   The 
  latitudes 
  thus 
  derived 
  are 
  affected 
  with 
  whatever 
  constant 
  

   error 
  inheres 
  in 
  the 
  declination 
  system 
  and 
  in 
  the 
  instrument 
  

   itself, 
  but 
  since 
  we 
  are 
  here 
  concerned 
  only 
  with 
  variations 
  of 
  

   latitude 
  constant 
  errors 
  are 
  of 
  no 
  consequence 
  and 
  we 
  may 
  

   therefore 
  neglect 
  the 
  absolute 
  value 
  of 
  the 
  latitude 
  and 
  inquire 
  

   what 
  interpretation 
  is 
  to 
  be 
  placed 
  upon 
  its 
  apparent 
  annual 
  

   increase. 
  

  

  I 
  do 
  not 
  think 
  that 
  it 
  will 
  be 
  seriously 
  maintained 
  by 
  any 
  

   competent 
  critic 
  that 
  this 
  variation 
  is 
  due 
  to 
  error 
  in 
  the 
  star 
  

   places 
  for, 
  the 
  same 
  stars 
  being 
  observed 
  year 
  after 
  year, 
  this 
  

   would 
  imply 
  that 
  the 
  mean 
  of 
  the 
  proper 
  motions 
  of 
  some 
  

   hundreds 
  of 
  fundamental 
  stars 
  is 
  in 
  error 
  to 
  the 
  amount 
  of 
  

   0"-06. 
  

  

  The 
  variation 
  may 
  be 
  due 
  to 
  accidental 
  error 
  of 
  observation, 
  

   but 
  the 
  uniform 
  progression 
  and 
  the 
  small 
  probable 
  errors 
  of 
  

   the 
  results 
  render 
  this 
  hypothesis 
  somewhat 
  improbable. 
  

  

  No 
  correction 
  for 
  flexure 
  has 
  been 
  applied 
  to 
  the 
  observa- 
  

   tions 
  and 
  it 
  may 
  be 
  supposed 
  that 
  the 
  variation 
  is 
  due 
  to 
  a 
  

   progressive 
  change 
  in 
  the 
  flexure 
  constants. 
  Nearly 
  forty 
  

   years 
  ago 
  W. 
  Struve 
  adopted 
  this 
  as 
  the 
  explanation 
  of 
  an 
  

   apparent 
  annual 
  variation 
  of 
  G^'06 
  in 
  the 
  latitude 
  of 
  Dorpat. 
  

  

  * 
  Computed 
  with 
  the 
  finally 
  adopted 
  elements 
  of 
  the 
  motion 
  of 
  the 
  pole. 
  

  

  