﻿[21] 
  

  

  REPORT 
  ON 
  THERMOMETERS. 
  

  

  205 
  

  

  iett, 
  U. 
  S. 
  Navy, 
  found 
  the 
  wooden 
  cases 
  shriveled 
  and 
  compressed 
  * 
  

   (the 
  pressure 
  at 
  800 
  fathoms 
  is 
  about 
  a 
  ton 
  to 
  the 
  square 
  inch), 
  so 
  that 
  

   their 
  buoyancy 
  "was 
  quite 
  lost. 
  Professor 
  Hilgard, 
  of 
  the 
  Coast 
  Survey, 
  

   suggested 
  the 
  use 
  of 
  a 
  metal 
  case, 
  filled 
  with 
  paraffine, 
  but 
  I 
  do 
  not 
  know 
  

   that 
  the 
  suggestion 
  was 
  ever 
  carried 
  out. 
  

  

  Lieut.-Commander 
  (then 
  lieutenant) 
  Z. 
  L. 
  Tanner, 
  U. 
  S. 
  Navy, 
  com- 
  

   manding 
  the 
  Fish 
  Commission 
  steamer 
  Fish 
  Hawk, 
  noted 
  in 
  18S0 
  that, 
  

   "The 
  bottom 
  and 
  intermediate 
  temperatures 
  were 
  unreliable, 
  owing 
  to 
  

   the 
  use 
  of 
  the 
  Negretti-Zambra 
  deep-sea 
  thermometer 
  in 
  a 
  sea-way, 
  the 
  

   motion 
  of 
  the 
  vessel 
  being 
  liable 
  to 
  capsize 
  it 
  at 
  any 
  time. 
  It 
  was 
  the 
  

   results 
  of 
  this 
  day's 
  work 
  [September 
  4, 
  1880] 
  that 
  led 
  us 
  to 
  devise 
  some 
  

   plan 
  by 
  which 
  this 
  admirable 
  thermometer 
  could 
  be 
  used 
  under 
  all 
  con- 
  

   ditions 
  of 
  wind 
  and 
  weather. 
  * 
  * 
  * 
  

  

  " 
  Several 
  devices 
  were 
  tried, 
  and 
  finally 
  a 
  simple 
  gas-pipe, 
  seven- 
  

   eighths 
  of 
  an 
  inch 
  inside 
  diameter, 
  was 
  adopted. 
  Several 
  holes 
  were 
  

   drilled 
  in 
  the 
  end 
  inclosing 
  the 
  bulb, 
  a 
  slit 
  cut 
  in 
  the 
  side 
  to 
  expose 
  the 
  

   scale, 
  and 
  a 
  pair 
  of 
  slip-hooks 
  held 
  in 
  position 
  by 
  a 
  small 
  spring 
  placed 
  

   in 
  the 
  opposite 
  end. 
  The 
  ther- 
  

   mometer 
  was 
  then 
  inserted, 
  the 
  

   rubber 
  guards 
  used 
  to 
  protect 
  the 
  

   shield 
  in 
  the 
  wooden 
  frame 
  serv- 
  

   ing 
  not 
  only 
  to 
  hold 
  it 
  securely 
  in 
  

   place 
  but 
  to 
  protect 
  it 
  from 
  sud- 
  

   den 
  jars, 
  and 
  a 
  lanyard 
  of 
  cod- 
  

   line, 
  spliced 
  into 
  the 
  end 
  carrying 
  

   the 
  bulb, 
  completed 
  the 
  arrange- 
  

   ment. 
  

  

  " 
  The 
  messenger 
  used 
  for 
  cap- 
  

   sizing 
  the 
  thermometer 
  is 
  of 
  cast 
  

   brass, 
  cylindrical 
  in 
  form, 
  with 
  

   rounded 
  ends. 
  It 
  is 
  about 
  2 
  

   inches 
  in 
  length, 
  1 
  in 
  diameter, 
  

   and 
  has 
  a 
  three-eighths 
  inch 
  hole 
  

   through 
  its 
  center, 
  well 
  rounded 
  

   at 
  the 
  ends 
  to 
  prevent 
  catching 
  on 
  

   splices. 
  Its 
  weight 
  is 
  from 
  3 
  to 
  

   4 
  ounces. 
  

  

  " 
  Fig. 
  13 
  shows 
  both 
  forms 
  of 
  

   the 
  Negretti-Zambra 
  thermometer 
  

   arranged 
  for 
  descent. 
  In 
  the 
  

   modified 
  form 
  it 
  is 
  held 
  firmly 
  in 
  

   position 
  by 
  the 
  slip-hooks 
  through 
  

   which 
  the 
  stray-line 
  passes. 
  

  

  "Having 
  attained 
  the 
  proper 
  

   depth, 
  and 
  sufficient 
  time 
  elapsed 
  

   for 
  the 
  thermometer 
  to 
  indicate 
  the 
  temperature, 
  the 
  messenger, 
  which 
  has 
  

  

  * 
  Sigsbee, 
  op. 
  cit,, 
  p. 
  116. 
  

  

  Fig. 
  13. 
  — 
  Sounding 
  machine, 
  with 
  Negretti-Zambra 
  

   deep-sea 
  thermometers 
  descending. 
  Shows 
  the 
  

   wooden 
  case 
  and 
  the 
  Tanner 
  metallic 
  case. 
  

  

  