﻿APPENDIX 
  C. 
  351 
  

  

  There 
  is 
  yet 
  another 
  means 
  of 
  determining 
  v 
  or 
  the 
  maximum 
  velocity 
  of 
  

   •movement 
  of 
  wave-particle, 
  and 
  that 
  is 
  by 
  means 
  of 
  bodies 
  which 
  have 
  been 
  

   projected 
  through 
  the 
  air 
  by 
  the 
  earthquake. 
  If 
  we 
  knew 
  the 
  exact 
  angle 
  

   at 
  which 
  they 
  started 
  on 
  their 
  course 
  it 
  would 
  be 
  easy 
  to 
  calculate 
  the 
  velocity 
  

   with 
  which 
  they 
  started 
  from 
  the 
  equation 
  

  

  -»-— 
  -** 
  (V) 
  

  

  2 
  cos 
  1 
  e(b 
  + 
  a 
  tan. 
  e) 
  

  

  where 
  a 
  and 
  b 
  are 
  the 
  horizontal 
  and 
  vertical 
  distances 
  through 
  which 
  the 
  centre 
  

   of 
  gravity 
  has 
  moved 
  (the 
  latter 
  downwards) 
  and 
  e 
  the 
  angle 
  with 
  the 
  horizon 
  at 
  

   which 
  it 
  was 
  projected 
  upwards. 
  

  

  In 
  practice 
  e 
  cannot 
  be 
  determined, 
  and 
  the 
  only 
  course 
  to 
  pursue 
  is 
  to 
  

   adopt 
  a 
  value 
  which 
  will 
  give 
  a 
  minimum 
  value 
  for 
  v. 
  Where 
  b 
  is 
  very 
  small 
  as 
  

   compared 
  with 
  a, 
  £ 
  may 
  be 
  taken 
  as 
  45 
  and 
  the 
  equation 
  becomes 
  

  

  (-45') 
  . 
  *=\/~h 
  {Vl) 
  

  

  which 
  becomes, 
  when 
  b 
  is 
  nothing, 
  as 
  in 
  the 
  case 
  of 
  projection 
  on 
  level 
  ground, 
  

  

  v~ 
  = 
  a 
  g 
  

   Where 
  b 
  is 
  much 
  greater 
  than 
  a, 
  or 
  the 
  drop 
  is 
  much 
  greater 
  than 
  the 
  horizontal 
  

   distance 
  travelled, 
  then 
  1 
  may 
  be 
  taken 
  as 
  o°, 
  that 
  is 
  to 
  say, 
  the 
  projection 
  is 
  

   horizontal, 
  and 
  the 
  formula 
  becomes 
  

  

  (< 
  = 
  0') 
  , 
  = 
  ^/'|| 
  (V 
  2) 
  

  

  Of 
  these 
  formula?, 
  that 
  for 
  deducing 
  the 
  acceleration 
  from 
  fracture 
  has 
  

   not 
  been 
  used, 
  except 
  in 
  the 
  case 
  of 
  the 
  marble 
  cross 
  in 
  the 
  Gauhati 
  cemetery. 
  

   In 
  the 
  case 
  of 
  the 
  broken 
  tombstones 
  and 
  Khasia 
  monuments 
  it 
  could 
  not 
  be 
  

   applied 
  owing 
  to 
  the 
  impossibility 
  of 
  determining 
  value 
  of 
  either 
  F 
  or 
  L, 
  nor 
  would 
  

   it 
  have 
  been 
  any 
  use 
  to 
  test 
  the 
  strength 
  of 
  pieces 
  of 
  stone 
  taken 
  from 
  the 
  

   monuments, 
  as 
  the 
  irregularity 
  of 
  the 
  weathering 
  the 
  stone 
  has 
  undergone 
  would 
  

   make 
  it 
  impossible 
  to 
  assert 
  more 
  than 
  that, 
  whatever 
  the 
  breaking 
  strain 
  of 
  the 
  

   piece 
  tested, 
  that 
  of 
  the 
  stone 
  on 
  the 
  fractured 
  surface 
  would 
  almost 
  certainly 
  be 
  

   different. 
  Similarly 
  the 
  irregularity 
  and 
  general 
  badness 
  of 
  the 
  brickwork 
  

   in 
  Assam 
  rendered 
  it 
  useless 
  to 
  attempt 
  to 
  determine 
  the 
  breaking 
  strain, 
  as 
  the 
  

   strength 
  along 
  different 
  joints, 
  in 
  the 
  same 
  pillar, 
  obviously 
  varied 
  very 
  much. 
  

  

  Generally 
  speaking, 
  it 
  seemed 
  as 
  if 
  the 
  strength 
  was 
  such 
  that 
  the 
  acceleration 
  

   required 
  to 
  produce 
  fracture 
  was 
  about 
  the 
  same 
  as 
  that 
  required 
  for 
  overthrow, 
  

   for, 
  of 
  the 
  cases 
  where 
  one 
  of 
  two 
  similar 
  pillars 
  were 
  overthrown 
  and 
  the 
  other 
  

   not, 
  there 
  were 
  about 
  an 
  equal 
  number 
  where 
  the 
  standing 
  pillar 
  was 
  cracked 
  

   across 
  and 
  where 
  it 
  was 
  uninjured. 
  

  

  Referring 
  to 
  the 
  tabular 
  statement 
  at 
  the 
  head 
  of 
  this 
  appendix 
  it 
  will 
  be 
  seen 
  

   that 
  the 
  values 
  obtained 
  for 
  the 
  acceleration 
  are 
  fairly 
  concordant 
  on 
  the 
  whole. 
  

   As 
  exceptions 
  must 
  be 
  noticed 
  the 
  cylinder 
  seismometer 
  at 
  Shillong, 
  the 
  tomb 
  

  

  ( 
  351 
  ) 
  

  

  