﻿W. 
  Bowie 
  — 
  Distribution 
  of 
  Isostatic 
  Compensation. 
  475 
  

  

  regional 
  distribution 
  of 
  the 
  compensation 
  out 
  from 
  the 
  station 
  

   to 
  a 
  distance 
  of 
  166*7 
  kilometers 
  is 
  farther 
  from 
  the 
  truth 
  than 
  

   the 
  local 
  distribution 
  or 
  than 
  the 
  regional 
  distribution 
  out 
  to 
  a 
  

   distance 
  of 
  18*8 
  kilometers 
  or 
  58*8 
  kilometers. 
  There 
  is 
  little 
  

   or 
  no 
  evidence 
  to 
  show 
  that 
  any 
  one 
  of 
  these 
  last 
  three 
  

   methods 
  is 
  nearer 
  the 
  truth 
  than 
  the 
  other 
  two. 
  It 
  may 
  be 
  

   possible 
  that 
  there 
  is 
  some 
  distance 
  between 
  58*8 
  kilometers 
  

   and 
  166*7 
  kilometers 
  which 
  would 
  give 
  a 
  slightly 
  smaller 
  

   range 
  of 
  the 
  mean 
  anomalies 
  with 
  regard 
  to 
  sign, 
  but 
  it 
  is 
  

   probable 
  that 
  there 
  is 
  not. 
  

  

  It 
  seems 
  improbable 
  that 
  further 
  computations 
  and 
  addi- 
  

   tional 
  data 
  can 
  evaluate 
  the 
  true 
  horizontal 
  distribution 
  of 
  the 
  

   compensation. 
  Therefore 
  in 
  making 
  the 
  computations 
  the 
  

   local 
  distribution 
  of 
  the 
  compensation 
  (horizontally) 
  may 
  with 
  

   propriety 
  be 
  continued 
  in 
  use. 
  

  

  The 
  mean 
  anomaly 
  with 
  regard 
  to 
  sign 
  for 
  the 
  various 
  

   classes 
  of 
  topography 
  by 
  the 
  Bouguer 
  method 
  of 
  reduction 
  has 
  

   such 
  a 
  wide 
  range 
  of 
  values 
  that 
  the 
  isostatic 
  method 
  by 
  any 
  

   one 
  of 
  the 
  distributions 
  under 
  consideration 
  appears 
  to 
  be 
  much 
  

   nearer 
  the 
  truth. 
  The 
  Bouguer 
  anomalies 
  with 
  regard 
  to 
  sign 
  

   for 
  217 
  stations 
  are 
  given 
  below. 
  

  

  Bouguer 
  

   Mean 
  Anomaly. 
  

   Dyne 
  

  

  2 
  7 
  coast 
  stations 
  +0*0 
  17 
  

  

  46 
  stations 
  near 
  the 
  coast 
  __, 
  + 
  0*004 
  

  

  88 
  stations 
  in 
  the 
  interior 
  not 
  in 
  mountainous 
  regions 
  — 
  0*028 
  

   36 
  stations 
  in 
  mountainous 
  regions, 
  below 
  the 
  general 
  

  

  level 
  _ 
  —0*107 
  

  

  20 
  stations 
  in 
  mountainous 
  regions, 
  above 
  the 
  general 
  

  

  level 
  _, 
  —0*110 
  

  

  217 
  stations, 
  all 
  classes 
  of 
  topography 
  —0*036 
  

  

  The 
  evidence 
  given 
  here 
  in 
  comparison 
  with 
  that 
  given 
  by 
  

   the 
  anomalies 
  of 
  the 
  isostatic 
  method 
  shows 
  that 
  the 
  Bouguer 
  

   method 
  has 
  no 
  general 
  application 
  whatever. 
  The 
  range 
  in 
  the 
  

   means 
  is 
  *127 
  dyne, 
  which 
  is 
  8 
  times 
  the 
  range 
  of 
  the 
  mean 
  

   regional 
  (horizontal) 
  isostatic 
  anomalies 
  with 
  compensation 
  uni- 
  

   formly 
  distributed 
  to 
  a 
  distance 
  of 
  166*7 
  kilometers, 
  and 
  25 
  

   times 
  the 
  range 
  of 
  the 
  mean 
  anomalies 
  with 
  local 
  distribution 
  

   of 
  the 
  compensation. 
  

  

  The 
  data 
  given 
  in 
  this 
  paper 
  favor 
  strongly 
  the 
  isostatic 
  

   method 
  of 
  reduction 
  and 
  also 
  favor 
  the 
  local 
  distribution 
  of 
  the 
  

   compensation 
  or 
  the 
  regional 
  distribution 
  to 
  a 
  distance 
  much 
  

   less 
  than 
  166*7 
  kilometers. 
  

  

  Division 
  of 
  Geodesy, 
  

  

  U. 
  S. 
  Coast 
  and 
  Geodetic 
  Survey. 
  

   April 
  20, 
  1917. 
  

  

  