﻿HOW 
  DEEP 
  IS 
  THE 
  OCEAN? 
  — 
  ABBOT. 
  

  

  279 
  

  

  and 
  lost, 
  leaving 
  for 
  a 
  time 
  dangerous 
  shoals 
  to 
  mark 
  its 
  sunken 
  

   place. 
  • 
  

  

  Recently, 
  as 
  the 
  result 
  of 
  attempts 
  by 
  our 
  Navy 
  during 
  the 
  war 
  to 
  

   locate 
  ships 
  and 
  submarines 
  by 
  the 
  sounds 
  they 
  make, 
  the 
  art 
  of 
  ocean 
  

   sounding 
  has 
  taken 
  a 
  great 
  step 
  forward. 
  A 
  device 
  called 
  the 
  " 
  MV 
  

   hydrophone 
  " 
  has 
  been 
  invented 
  and 
  perfected 
  to 
  such 
  a 
  high 
  degree 
  

   that 
  in 
  favorable 
  cases 
  sounds 
  coming 
  as 
  far 
  as 
  20 
  miles 
  can 
  be 
  heard 
  

   and 
  located 
  in 
  direction. 
  By 
  this 
  ingenious 
  device, 
  and 
  modifica- 
  

   tions 
  of 
  it 
  made 
  under 
  the 
  direction 
  of 
  Dr. 
  H. 
  C. 
  Hayes, 
  of 
  the 
  Navy, 
  

   it 
  has 
  become 
  possible 
  to 
  locate 
  

   by 
  sound 
  ships, 
  shoals, 
  pre- 
  

   cipitous 
  shores, 
  icebergs, 
  and 
  

   " 
  sound 
  beacons 
  " 
  and 
  to 
  com- 
  

   municate 
  by 
  sound 
  from 
  ship 
  

   to 
  ship. 
  Not 
  only 
  so, 
  but 
  a 
  

   means 
  has 
  been 
  perfected 
  and 
  

   applied 
  with 
  the 
  most 
  complete 
  

   success 
  whereby 
  the 
  depth 
  of 
  

   the 
  ocean 
  can 
  be 
  measured 
  con- 
  

   tinuously 
  by 
  a 
  vessel 
  proceed- 
  

   ing 
  at 
  good 
  speed 
  on 
  her 
  

   course. 
  

  

  Just 
  as 
  our 
  heads 
  have 
  two 
  

   ears, 
  by 
  means 
  of 
  which 
  we 
  

   judge 
  of 
  sound 
  directions 
  in- 
  

   stinctively 
  because 
  it 
  takes 
  

   sounds 
  from 
  our 
  right 
  a 
  trifle 
  

   longer 
  to 
  reach 
  the 
  left 
  ear, 
  and 
  

   vice 
  versa, 
  so 
  the 
  MV 
  hydro- 
  

   phone 
  has 
  two 
  sets 
  of 
  sound 
  re- 
  

   ceivers 
  placed 
  one 
  on 
  each 
  side 
  

   deep 
  down 
  attached 
  under 
  the 
  

   ship's 
  bottom. 
  As 
  it 
  is 
  not 
  con- 
  

   venient 
  to 
  turn 
  the 
  ship 
  toward 
  

   the 
  sound, 
  as 
  we 
  do 
  with 
  our 
  heads, 
  until 
  the 
  sounds 
  reach 
  the 
  two 
  

   sets 
  of 
  receivers 
  simultaneously, 
  an 
  electrical 
  arrangement 
  is 
  provided 
  

   for 
  retarding 
  the 
  sounds 
  from 
  receivers 
  which 
  get 
  it 
  first 
  until 
  all 
  

   come 
  in 
  unison 
  into 
  the 
  double 
  telephone 
  headpiece 
  of 
  the 
  observer. 
  

  

  This 
  retardation 
  principle 
  is 
  carried 
  still 
  further, 
  for 
  the 
  two 
  

   groups 
  on 
  either 
  side 
  of 
  the 
  ship 
  each 
  contain 
  12 
  receivers 
  spaced 
  12 
  

   inches 
  apart 
  in 
  a 
  row 
  parallel 
  to 
  the 
  ship's 
  length. 
  Hence 
  it 
  is 
  only 
  

   found 
  sounds 
  coming 
  in 
  exactly 
  at 
  right 
  angles 
  that 
  there 
  is 
  no 
  dif- 
  

   ference 
  in 
  times 
  of 
  receipt 
  by 
  the 
  separate 
  instruments 
  of 
  each 
  bank. 
  

   Thus 
  each 
  set 
  alone 
  by 
  itself 
  is 
  a 
  direction 
  finder, 
  but 
  it 
  takes 
  both 
  

  

  Fig. 
  2. 
  — 
  Section 
  of 
  bow 
  tank 
  showing 
  relative 
  

   location 
  of 
  port 
  and 
  starboard 
  receiver 
  lines 
  

   and 
  intervening 
  sound 
  screens. 
  

  

  