﻿Preston 
  — 
  Direction 
  of 
  Gravity 
  in 
  the 
  Hawaiian 
  Is. 
  271 
  

  

  Art. 
  XXII. 
  — 
  Disturbances 
  in 
  the 
  direction 
  of 
  the 
  Plumb-line 
  

   in 
  the 
  Hawaiian 
  Islands 
  ; 
  by 
  E. 
  D. 
  Preston. 
  

  

  Professor 
  Alexander, 
  Surveyor 
  General 
  of 
  Hawaii 
  has 
  

   made 
  a 
  comparison 
  of 
  the 
  astronomical 
  and 
  geodetic 
  latitudes 
  

   on 
  the 
  three 
  principal 
  islands 
  of 
  the 
  group. 
  In 
  addition 
  to 
  

   this, 
  since 
  the 
  observed 
  latitudes 
  at 
  Kawaihae, 
  Hilo, 
  and 
  

   Waiau 
  (Mauna 
  Kea) 
  are 
  consistent 
  with 
  one 
  another 
  the 
  latter 
  

   has 
  been 
  adopted 
  as 
  a 
  standard 
  and 
  a 
  comparison 
  has 
  been 
  

   made 
  between 
  the 
  observed 
  latitudes 
  and 
  the 
  Mauna 
  Kea 
  

   standard. 
  This 
  brings 
  out 
  some 
  interesting 
  deflections 
  of 
  the 
  

   plumb-line. 
  See 
  Fig. 
  1. 
  

  

  Scale 
  100 
  miles 
  to 
  one 
  inch. 
  

  

  There 
  appears 
  to 
  be 
  a 
  disturbance 
  of 
  more 
  than 
  a 
  minute 
  in 
  

   the 
  direction 
  of 
  gravity 
  at 
  the 
  south 
  point 
  of 
  Hawaii 
  (Ka 
  Lae). 
  

   At 
  Kohala 
  the 
  plumb-line 
  is 
  deflected 
  half 
  a 
  minute 
  towards 
  

   the 
  south 
  and 
  at 
  Kalaieha 
  nearly 
  as 
  much 
  towards 
  the 
  north, 
  

   the 
  disturbance 
  being 
  in 
  both 
  cases 
  towards 
  the 
  mountain. 
  

   The 
  enormous 
  deflection 
  at 
  Ka 
  Lae 
  (67") 
  is 
  also 
  to 
  the 
  north- 
  

   ward. 
  This 
  is 
  evidently 
  caused 
  by 
  the 
  great 
  mass 
  of 
  Mauna 
  

   Loa,* 
  which 
  adds 
  its 
  effect 
  to 
  that 
  of 
  Mauna 
  Kea 
  and 
  more- 
  

   over 
  is 
  comparatively 
  near 
  to 
  the 
  astronomical 
  station. 
  

  

  On 
  Maui 
  the 
  same 
  phenomenon 
  appears. 
  At 
  Haiku 
  there 
  

   is 
  a 
  deflection 
  towards 
  the 
  south 
  and 
  at 
  Kaupo 
  there 
  is 
  one 
  to 
  

   the 
  north, 
  and 
  as 
  before 
  the 
  astronomical 
  latitude 
  determined 
  

  

  * 
  Both 
  Mauna 
  Kea 
  and 
  Mauna 
  Loa 
  are 
  nearly 
  14,000 
  feet 
  high. 
  

  

  