﻿W. 
  Bowie 
  — 
  Distribution 
  of 
  Isostatio 
  Compensation. 
  473 
  

  

  It 
  is 
  readily 
  seen 
  that 
  the 
  compensation 
  would 
  be 
  the 
  same 
  

   under 
  the 
  several 
  methods 
  of 
  distribution 
  at 
  a 
  station 
  located 
  

   on 
  a 
  coastal 
  plain 
  or 
  on 
  an 
  extensive 
  plateau. 
  But 
  if 
  the 
  area 
  

   about 
  a 
  station 
  has 
  varied 
  topography 
  as 
  in 
  mountainous 
  

   regions, 
  the 
  effect 
  of 
  the 
  compensation 
  will 
  vary 
  with 
  the 
  

   method 
  of 
  distribution 
  employed. 
  If 
  the 
  station 
  is 
  on 
  a 
  moun- 
  

   tain 
  peak 
  the 
  regional 
  distribution 
  will 
  place 
  some 
  of 
  the 
  com- 
  

   pensation 
  at 
  a 
  distance, 
  horizontally, 
  and 
  its 
  effect 
  at 
  the 
  station 
  

   will 
  be 
  lessened. 
  On 
  the 
  other 
  hand, 
  if 
  the 
  station 
  is 
  in 
  a 
  val- 
  

   ley, 
  the 
  regional 
  distribution 
  will 
  place 
  under 
  the 
  station 
  some 
  

   of 
  the 
  compensation 
  of 
  the 
  mountain 
  mass, 
  and 
  the 
  compensa- 
  

   tion 
  will 
  have 
  a 
  greater 
  effect 
  on 
  the 
  gravity 
  at 
  the 
  station 
  

   than 
  is 
  the 
  case 
  with 
  local 
  distribution. 
  

  

  If 
  we 
  assume, 
  as 
  we 
  must 
  in 
  these 
  tests, 
  that 
  the 
  anomalies 
  

   are 
  due 
  entirely 
  to 
  the 
  departures 
  from 
  the 
  truth 
  in 
  the 
  method 
  

   of 
  horizontal 
  distribution 
  of 
  the 
  compensation, 
  then 
  we 
  are 
  

   justified 
  in 
  concluding 
  that 
  that 
  method 
  of 
  distribution 
  is 
  

   nearest 
  the 
  truth 
  which 
  shows 
  the 
  least 
  effect 
  of 
  systematic 
  

   errors, 
  in 
  the 
  anomalies 
  for 
  the 
  various 
  classes 
  of 
  topography. 
  

  

  The 
  stations 
  were 
  therefore 
  arranged 
  in 
  five 
  groups 
  accord- 
  

   ing 
  to 
  the 
  topography. 
  The 
  mean 
  local 
  and 
  regional 
  anomalies 
  

   for 
  these 
  groups 
  are 
  given 
  in 
  the 
  following 
  table 
  : 
  

  

  Local 
  and 
  Regional 
  Anomalies. 
  

  

  For 
  18 
  coast 
  stations. 
  

  

  Local 
  Regional 
  Anomalies 
  

  

  Anomalies 
  Zone 
  K 
  Zone 
  M 
  Zone 
  O 
  

  

  Mean 
  with 
  regard 
  to 
  sign 
  —0'004 
  —0*004 
  —0*004 
  —0*006 
  

   Mean 
  without 
  regard 
  to 
  sign 
  0"018 
  0*018 
  0*018 
  0*020 
  

  

  For 
  25. 
  stations 
  near 
  coast. 
  

  

  Mean 
  with 
  regard 
  to 
  sign 
  —0*002 
  —0*001 
  —0 
  001 
  —0*001 
  

   Mean 
  without 
  regard 
  to 
  sign 
  0*022 
  0*021 
  0021 
  0*022 
  

  

  For 
  39 
  stations 
  in 
  the 
  interior, 
  not 
  in 
  mountainous 
  regions. 
  

  

  Mean 
  with 
  regard 
  to 
  sign 
  +0*001 
  +0*002 
  +0*002 
  +0*003 
  

   Mean 
  without 
  regard 
  to 
  sign 
  0*017 
  0*018 
  0*018 
  0*017 
  

  

  For 
  22 
  stations, 
  in 
  mountainous 
  regions, 
  below 
  the 
  general 
  level. 
  

  

  Mean 
  with 
  regard 
  to 
  sign 
  0*000 
  +0*001 
  +0*003 
  +0*006 
  

  

  Mean 
  without 
  regard 
  to 
  sign 
  0*017 
  0*017 
  0*018 
  0*019 
  

  

  For 
  18 
  stations, 
  in 
  mountainous 
  regions, 
  above 
  the 
  general 
  level. 
  

  

  Mean 
  with 
  regard 
  to 
  sign 
  +0*003 
  +0*003 
  0*000 
  —0*010 
  

  

  Mean 
  without 
  regard 
  to 
  sign 
  0018 
  0*018 
  0*017 
  0*020 
  

  

  The 
  means 
  without 
  regard 
  to 
  sign 
  for 
  the 
  anomalies 
  .by 
  the 
  

   several 
  methods 
  of 
  distribution 
  are 
  practically 
  the 
  same 
  for 
  the 
  

   five 
  classes 
  of 
  topography 
  considered. 
  This 
  is 
  a 
  striking 
  con- 
  

   firmation 
  of 
  the 
  theory 
  of 
  isostasy. 
  This 
  is 
  shown 
  when 
  we 
  

  

  