﻿APPENDIX 
  G. 
  361 
  

  

  November 
  15th 
  4-50 
  Shillong, 
  severe 
  ; 
  felt 
  ios. 
  after 
  Gauhati. 
  

  

  „ 
  17th 
  20-17 
  Shillong, 
  very 
  severe, 
  felt 
  by 
  Gauhati 
  and 
  Sylhet 
  at 
  

  

  the 
  same 
  time. 
  

  

  „ 
  26th 
  9-50 
  Shillong, 
  severe, 
  felt 
  by 
  us 
  about 
  2s. 
  after 
  Gauhati. 
  

  

  December 
  17th 
  17-42 
  Gauhati, 
  felt 
  3s. 
  before 
  Shillong. 
  

  

  Appendix 
  G. 
  

  

  Details 
  and 
  Discussion 
  of 
  the 
  results 
  of 
  the 
  Revisionary 
  Triangu- 
  

   lation 
  of 
  the 
  Khasi 
  Hills, 
  carried 
  out 
  by 
  the 
  Great 
  Trigono- 
  

   metrical 
  Survey 
  in 
  the 
  season 
  1897-98. 
  

  

  The 
  accumulation 
  of 
  independent 
  evidence, 
  from 
  many 
  witnesses 
  and 
  widely 
  

   separated 
  places, 
  all 
  pointing 
  to 
  the 
  fact 
  that 
  the 
  earthquake 
  had 
  been 
  accom- 
  

   panied 
  by 
  noticeable 
  changes 
  in 
  the 
  relative 
  heights 
  of 
  peaks 
  in 
  the 
  Khasi 
  and 
  Garo 
  

   Hills, 
  led 
  the 
  Government 
  of 
  Assam 
  and 
  the 
  Director 
  of 
  the 
  Geological 
  Survey 
  

   almost 
  simultaneously 
  to 
  represent 
  to 
  the 
  Government 
  of 
  India 
  the 
  desirability 
  

   of 
  testing 
  the 
  accuracy 
  of 
  these 
  statements 
  by 
  a 
  revision 
  of 
  the 
  triangulation 
  

   of 
  the 
  hills. 
  The 
  representations 
  met 
  with 
  a 
  favourable 
  reception; 
  it 
  was 
  

   decided 
  that 
  retriangulation 
  should 
  be 
  taken 
  in 
  hand 
  during 
  the 
  cold 
  weather 
  

   of 
  1897, 
  and 
  as 
  much 
  done 
  as 
  was 
  compatible 
  with 
  the 
  other 
  calls 
  on 
  the 
  staff 
  of 
  the 
  

   Great 
  Trigonometrical 
  Survey. 
  In 
  pursuance 
  of 
  this 
  decision, 
  a 
  programme 
  of 
  

   work 
  to 
  be 
  done 
  was 
  drawn 
  up 
  by 
  Major 
  S. 
  G. 
  Burrard, 
  R.E., 
  Officiating 
  Super, 
  

   intendent 
  of 
  Trigonometrical 
  Surveys, 
  in 
  consultation 
  with 
  myself. 
  

  

  At 
  the 
  outset 
  it 
  became 
  evident 
  that 
  what 
  was 
  desirable 
  was 
  not 
  possible, 
  owing 
  

   to 
  the 
  calls 
  on 
  the 
  Trigonometrical 
  Survey 
  due 
  to 
  the 
  total 
  solar 
  eclipse, 
  and 
  to 
  the 
  

   regular 
  work 
  wl 
  ich 
  could 
  not 
  be 
  interrupted. 
  Only 
  one 
  observer 
  could 
  be 
  deputed 
  

   for 
  the 
  revisionary 
  triangulation, 
  and 
  the 
  only 
  instrument 
  available, 
  though 
  an 
  ex- 
  

   cellent 
  one, 
  was 
  not 
  of 
  the 
  power 
  considered 
  necessary 
  for 
  primary 
  triangulation. 
  

   In 
  these 
  circumstances 
  a 
  compromise 
  was 
  made 
  between 
  what 
  was 
  desirable 
  and 
  

   what 
  was 
  possible, 
  and 
  the 
  decision 
  come 
  to 
  was 
  to 
  reobserve 
  certain 
  triangles 
  in 
  

   the 
  Khasi 
  hills, 
  and, 
  if 
  time 
  allowed, 
  certain 
  others 
  in 
  the 
  western 
  Garo 
  Hills. 
  This 
  

   latter 
  part 
  of 
  the 
  programme 
  it 
  was 
  not 
  possible 
  to 
  carry 
  out, 
  and 
  the 
  triangles 
  

   actually 
  observed 
  were 
  those 
  represented 
  on 
  Plate 
  XLIII. 
  

  

  In 
  coming 
  to 
  this 
  decision 
  it 
  was 
  recognised 
  that 
  a 
  triangulation 
  so 
  much 
  in 
  the 
  

   air, 
  and 
  unconnected 
  with 
  any 
  points 
  which 
  could 
  with 
  any 
  degree 
  of 
  certainty 
  be 
  

   regarded 
  as 
  undisturbed, 
  would 
  give 
  no 
  information 
  as 
  to 
  absolute 
  displacements, 
  

   whether 
  vertical 
  or 
  horizontal. 
  All 
  that 
  was 
  looked 
  for 
  was 
  a 
  discovery 
  of 
  whether 
  

   there 
  had 
  been 
  any 
  relative 
  displacements 
  of 
  the 
  trigonometrical 
  stations; 
  if 
  none 
  

   such 
  were 
  found, 
  it 
  would 
  be 
  certain 
  that 
  no 
  general 
  displacement, 
  which 
  would 
  

   be 
  detected, 
  had 
  taken 
  place. 
  With 
  such 
  an 
  object 
  in 
  view 
  it 
  was 
  obviously 
  ne- 
  

   cessary 
  that 
  the 
  triangles 
  selected 
  for 
  reobservation 
  should 
  be 
  situated 
  where 
  there 
  

   was 
  the 
  greatest 
  inherent 
  probability 
  of 
  their 
  having 
  undergone 
  distortion. 
  At 
  the 
  

   time 
  the 
  decision 
  was 
  come 
  to, 
  the 
  exploration 
  of 
  the 
  epicentral 
  region, 
  described 
  in 
  

   Chapter 
  IX, 
  had 
  not 
  been 
  commenced, 
  and 
  we 
  were 
  still 
  under 
  the 
  impression 
  that 
  

   the 
  focus 
  most 
  probably 
  lay 
  under 
  the 
  southern 
  part 
  of 
  the 
  Khasi 
  Hills. 
  

  

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