﻿232 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  (1933), 
  under 
  a 
  grant 
  from 
  the 
  Penrose 
  Bequest 
  of 
  the 
  Geological 
  

   Society 
  of 
  America, 
  the 
  detailed 
  work 
  in 
  some 
  of 
  the 
  California 
  sub- 
  

   marine 
  canyons 
  both 
  by 
  the 
  Survey 
  and 
  by 
  the 
  Scripps 
  Institution, 
  and 
  

   the 
  chart 
  of 
  the 
  submarine 
  contours 
  around 
  Bogoslof 
  Island 
  (Smith, 
  

   1937) 
  are 
  but 
  forerunners 
  of 
  a 
  type 
  of 
  work 
  which 
  we 
  may 
  expect 
  

   in 
  the 
  future 
  to 
  become 
  universal. 
  

  

  TERRESTRIAL 
  MAGNETISM 
  

  

  Magnetic 
  surveys 
  at 
  sea, 
  according 
  to 
  Dr. 
  J. 
  A. 
  Fleming 
  (Vaughan 
  

   et 
  al., 
  1937, 
  pp. 
  50-56), 
  were 
  first 
  attempted 
  over 
  200 
  years 
  ago 
  on 
  

   Halley's 
  expedition. 
  From 
  that 
  time 
  until 
  the 
  construction 
  in 
  1908 
  

   of 
  a 
  nonmagnetic 
  ship 
  by 
  the 
  Department 
  of 
  Terrestrial 
  Magnetism 
  

   of 
  the 
  Carnegie 
  Institution 
  of 
  Washington, 
  other 
  surveys 
  of 
  varying 
  

   accuracy 
  were 
  made, 
  depending 
  on 
  the 
  instruments 
  used 
  and 
  the 
  

   amount 
  of 
  magnetic 
  disturbance 
  set 
  up 
  by 
  the 
  hulls 
  of 
  the 
  different 
  

   vessels. 
  The 
  commissioning 
  of 
  the 
  Carnegie, 
  however, 
  marks 
  the 
  

   awakening 
  of 
  a 
  full 
  appreciation 
  of 
  the 
  value 
  of 
  magnetic 
  measure- 
  

   ments 
  at 
  sea 
  and 
  a 
  concerted 
  effort 
  to 
  make 
  them 
  as 
  accurate 
  as 
  possible 
  

   by 
  the 
  optimum 
  equipment 
  and 
  by 
  long 
  cruises 
  devoted 
  exclusively 
  to 
  

   this 
  aim. 
  Seven 
  cruises 
  totaling 
  nearly 
  300,000 
  miles 
  were 
  made 
  

   before 
  this 
  ship 
  was 
  destroyed 
  by 
  fire 
  in 
  1929. 
  

  

  Any 
  investigation 
  that 
  holds 
  the 
  possibility 
  of 
  making 
  more 
  com- 
  

   plete 
  our 
  knowledge 
  of 
  the 
  earth's 
  structure 
  is 
  worth 
  pursuing 
  for 
  

   its 
  own 
  sake; 
  furthermore, 
  data 
  accumulated 
  in 
  this 
  field 
  can 
  also 
  

   be 
  used 
  to 
  advantage 
  in 
  other 
  branches 
  of 
  geophysics, 
  particularly 
  

   gravimetric 
  studies. 
  This 
  being 
  the 
  case, 
  the 
  need 
  for 
  additional 
  

   observations 
  at 
  sea 
  are 
  self-evident, 
  considering 
  the 
  large 
  portion 
  of 
  

   the 
  earth's 
  crust 
  that 
  is 
  covered 
  with 
  water, 
  and 
  entirely 
  aside 
  from 
  

   the 
  practical 
  values 
  of 
  these 
  studies 
  as 
  an 
  aid 
  to 
  navigation 
  at 
  sea 
  

   and 
  in 
  the 
  air. 
  

  

  Fleming 
  (Vaughan 
  et 
  al., 
  1937, 
  p. 
  53) 
  lists 
  a 
  few 
  theoretical 
  investi- 
  

   gations 
  which 
  should 
  be 
  continued 
  in 
  the 
  further 
  survey 
  of 
  the 
  oceans 
  : 
  

  

  Determination 
  of 
  secular-variation 
  of 
  progressive 
  changes 
  of 
  the 
  Earth's 
  mag- 
  

   netic 
  field 
  involving 
  particularly 
  their 
  accelerations 
  * 
  * 
  *. 
  The 
  study 
  of 
  

   regions 
  of 
  local 
  disturbance 
  and 
  particularly 
  of 
  those 
  indicated 
  * 
  * 
  * 
  over 
  

   "deep-sea" 
  areas 
  * 
  * 
  *. 
  The 
  determination 
  of 
  additional 
  distribution-data 
  

   in 
  a 
  few 
  large 
  areas 
  not 
  already 
  covered. 
  

  

  Simultaneously 
  with 
  these 
  investigations 
  work 
  should 
  be 
  continued 
  

  

  in 
  the 
  field 
  of 
  terrestrial 
  electricity 
  along 
  the 
  following 
  lines 
  : 
  

  

  Additional 
  determinations 
  to 
  establish 
  changes 
  in 
  the 
  values 
  of 
  the 
  atmos- 
  

   pheric-electric 
  elements 
  with 
  geographic 
  position. 
  * 
  * 
  * 
  More 
  and 
  widely 
  

   distributed 
  determinations 
  of 
  the 
  diurnal 
  variations 
  in 
  atmospheric 
  elec- 
  

   tricity 
  * 
  * 
  *. 
  Determinations 
  and 
  investigations 
  in 
  the 
  field 
  of 
  earth-cur- 
  

   rents 
  — 
  a 
  field 
  not 
  yet 
  touched 
  at 
  sea. 
  

  

  Although 
  the 
  Carnegie 
  Institution 
  did 
  not 
  build 
  another 
  ship, 
  the 
  

   British 
  Admiralty, 
  in 
  view 
  of 
  the 
  importance 
  of 
  these 
  investigations, 
  

  

  