﻿RATE 
  OF 
  PROPAGATION. 
  55 
  

  

  recorded 
  times 
  from 
  individual 
  stations. 
  The 
  records 
  obtained 
  from 
  

   the 
  main 
  line 
  stations 
  between 
  Calcutta 
  and 
  Delhi 
  were 
  plotted 
  and 
  

   a 
  curve 
  drawn 
  (see 
  Plate 
  XXXIX) 
  in 
  which 
  the 
  abscissae 
  represent 
  

   the 
  distance 
  of 
  the 
  stations, 
  the 
  ordinates 
  the 
  times 
  ; 
  the 
  curve 
  so 
  

   obtained 
  is 
  irregular, 
  but 
  by 
  smoothing 
  it 
  a 
  curve 
  was 
  obtained 
  which 
  

   gives 
  the 
  probable 
  time 
  of 
  commencement 
  of 
  the 
  shock 
  at 
  each 
  

   station 
  with 
  greater 
  accuracy 
  than 
  the 
  actually 
  recorded 
  times. 
  

  

  The 
  same 
  method 
  was 
  attempted 
  in 
  the 
  case 
  of 
  the 
  Eastern 
  Bengal 
  

   State 
  Railway 
  line 
  from 
  Calcutta 
  to 
  Darjiling, 
  but 
  in 
  this 
  case 
  the 
  

   individual 
  variations 
  in 
  time 
  between 
  neighbouring 
  stations, 
  and 
  the 
  

   very 
  large 
  proportion 
  which 
  gave 
  what 
  was 
  evidently 
  merely 
  the 
  

   nearest 
  five 
  minute 
  interval 
  renders 
  the 
  method 
  inapplicable. 
  In 
  this 
  

   case, 
  as 
  in 
  that 
  of 
  all 
  the 
  other 
  lines 
  from 
  which 
  returns 
  have 
  been 
  

   obtained, 
  it 
  has 
  been 
  necessary 
  to 
  adopt 
  the 
  less 
  satisfactory 
  

   method 
  of 
  selecting 
  those 
  of 
  the 
  returns 
  which 
  appear 
  on 
  the 
  face 
  of 
  

   them 
  to 
  be 
  most 
  trustworthy. 
  

  

  The 
  fourth 
  category, 
  voluntary 
  reports 
  from 
  private 
  individuals, 
  

   varies 
  most 
  largely 
  in 
  value. 
  In 
  a 
  certain 
  number 
  of 
  cases 
  every 
  

   care 
  seems 
  to 
  have 
  been 
  taken 
  to 
  ensure 
  accuracy, 
  and 
  it 
  is 
  expressly 
  

   stated 
  that 
  the 
  watch 
  or 
  clock, 
  by 
  which 
  the 
  time 
  was 
  taken, 
  had 
  

   been 
  or 
  was 
  subsequently 
  compared 
  with 
  the 
  timepiece 
  of 
  the 
  near- 
  

   est 
  station 
  or 
  telegraph 
  office, 
  or 
  with 
  the 
  daily 
  gun. 
  All 
  these 
  stan- 
  

   dards 
  are, 
  however, 
  liable 
  to 
  errors 
  which 
  may 
  — 
  for 
  the 
  present 
  

   purpose 
  — 
  wholly 
  vitiate 
  the 
  result. 
  

  

  A 
  fruitful 
  source 
  of 
  error, 
  and 
  one 
  that 
  it 
  is 
  often 
  impossible 
  to 
  

   eliminate, 
  fs 
  the 
  different 
  times 
  that 
  are 
  kept 
  and 
  used. 
  I 
  do 
  not 
  refer 
  

   to 
  isolated 
  localities 
  where 
  there 
  is 
  neither 
  railway 
  station 
  nor 
  tele- 
  

   graph 
  office, 
  and 
  where 
  the 
  local 
  time 
  is 
  determined 
  by 
  the 
  gastric 
  

   sensations 
  of 
  the 
  individual 
  in 
  charge 
  of 
  the 
  station 
  timcgong, 
  or 
  

   the 
  indications 
  of 
  a 
  sundial, 
  more 
  often 
  than 
  not 
  constructed 
  for 
  a 
  

   different 
  latitude 
  to 
  that 
  in 
  which 
  it 
  is 
  set 
  up, 
  and 
  probably 
  adjusted 
  to 
  

   the 
  meridian 
  with 
  no 
  more 
  accurate 
  instrument 
  than 
  a 
  cheap 
  pocket 
  

   compass 
  ; 
  but 
  to 
  those 
  places 
  where 
  the 
  presence 
  of 
  telegraphic 
  

   communication 
  should 
  enable 
  accurate 
  time 
  to 
  be 
  kept. 
  

  

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  55 
  ) 
  

  

  