﻿242 
  OLDHAM: 
  GREAT 
  EARTHQUAKE 
  OF 
  1897. 
  

  

  Horizontal 
  Force, 
  First, 
  small, 
  shock 
  at 
  uh. 
  24m., 
  G. 
  M. 
  T, 
  

   last 
  at 
  I2h. 
  55m, 
  

  

  Vertical 
  force, 
  First 
  shock 
  at 
  uh. 
  23m., 
  others 
  until 
  nh. 
  43m. 
  

   Electrometer, 
  (Mascart's 
  type) 
  commencement 
  I 
  ih. 
  17m., 
  end 
  

   at 
  about 
  uh. 
  53m. 
  

  

  The 
  disturbances 
  are 
  of 
  the 
  same 
  type 
  as 
  those 
  of 
  the 
  Bombay 
  

   instruments, 
  but 
  less 
  extensive. 
  

  

  Potsdam 
  — 
  The 
  instruments 
  are 
  similar 
  to 
  the 
  Kew 
  instruments 
  

   but 
  smaller 
  in 
  size. 
  All 
  three 
  were 
  affected 
  by 
  the 
  earthquake. 
  The 
  

   times 
  of 
  commencement 
  were— 
  

  

  Declination 
  . 
  . 
  . 
  uh. 
  i8*75m. 
  G. 
  M. 
  T. 
  

   Vertical 
  force 
  • 
  . 
  . 
  uh. 
  i8*25m. 
  „ 
  

  

  The 
  exact 
  time 
  of 
  commencement 
  cannot 
  be 
  determined 
  on 
  the 
  

   trace 
  of 
  the 
  horizontal 
  force 
  instrument, 
  but 
  there 
  is 
  a 
  perceptible 
  

   widening 
  of 
  the 
  line 
  commencing 
  at 
  about 
  uh. 
  10m., 
  though 
  the 
  first 
  

   definite 
  disturbance 
  is 
  not 
  for 
  some 
  6 
  or 
  7 
  minutes 
  later. 
  The 
  ter- 
  

   mination 
  of 
  the 
  disturbance 
  is 
  at 
  about 
  I2h. 
  40m. 
  G. 
  M. 
  T. 
  on 
  the 
  

   trace 
  of 
  the 
  declination 
  instrument, 
  and 
  about 
  i2h. 
  28m. 
  on 
  that 
  of 
  the 
  

   vertical 
  force 
  instrument. 
  On 
  the 
  horizontal 
  force 
  instrument 
  there 
  

   are 
  a 
  number 
  of 
  small 
  oscillations 
  lasting 
  till 
  about 
  13b. 
  42m. 
  G. 
  M.T. 
  

  

  The 
  times 
  of 
  commencement 
  were 
  measured 
  at 
  Potsdam 
  on 
  the 
  

   original 
  records 
  and 
  are 
  accurate 
  within 
  a 
  limit 
  of 
  '5m. 
  The 
  

   others 
  are 
  taken 
  from 
  photographs 
  of 
  the 
  traces, 
  for 
  which 
  I 
  am 
  in- 
  

   debted 
  to 
  Dr. 
  Eschenhagen, 
  and 
  cannot 
  be 
  trusted 
  within, 
  say, 
  2 
  

   minutes 
  of 
  time. 
  I 
  am 
  also 
  indebted 
  to 
  Dr. 
  Eschenhagen 
  for 
  the 
  

   information 
  that 
  the 
  maximum 
  displacement 
  recorded 
  by 
  the 
  horizontal 
  

   force 
  instrument 
  was 
  at 
  uh. 
  4875m. 
  G. 
  M. 
  T., 
  but, 
  as 
  the 
  time 
  

   for 
  changing 
  the 
  recording 
  papers 
  fell 
  just 
  as 
  the 
  instruments 
  were 
  

   being 
  affected 
  by 
  the 
  earthquake, 
  there 
  may 
  have 
  been 
  a 
  greater 
  

   movement 
  subsequent 
  to 
  this. 
  

  

  Wilhelmshaven, 
  — 
  The 
  magnetic 
  instruments 
  at 
  Wilhelmahaven 
  

  

  ( 
  242 
  ) 
  

  

  