﻿193 
  

  

  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [14] 
  

  

  Fig. 
  6. 
  — 
  Sixe's 
  self-register- 
  

   ing 
  maximum 
  and 
  mini- 
  

   mum 
  thermometer. 
  

  

  excepting 
  in 
  that 
  the 
  larger 
  bulb 
  was 
  protected 
  as 
  described 
  above. 
  

   (Fig. 
  6.) 
  A 
  smaller 
  and 
  more 
  compact 
  instrument, 
  with 
  the 
  tube 
  bent 
  

   but 
  once, 
  in 
  U 
  -shape, 
  was 
  constructed 
  for 
  the 
  reg- 
  

   istration 
  of 
  minimum 
  temperatures 
  only. 
  The 
  cop- 
  

   per 
  case 
  inclosing 
  this 
  last-named 
  instrument 
  was 
  

   made, 
  by 
  a 
  poppet 
  valve 
  at 
  the 
  top 
  and 
  bottom, 
  

   opening 
  up 
  ward, 
  to 
  serve 
  also 
  as 
  a 
  water-bottle. 
  

   (Fig. 
  7.) 
  

  

  After 
  the 
  appearance 
  of 
  the 
  form 
  

   now 
  in 
  common 
  use, 
  under 
  the 
  name 
  

   of 
  the 
  "Miller-Casella" 
  or 
  "Casella- 
  

   Miller" 
  deep-sea 
  thermometer, 
  the 
  

   question 
  of 
  its 
  authorship 
  was 
  made 
  

   the 
  subject 
  of 
  a 
  somewhat 
  acrimo- 
  

   nious 
  correspondence 
  in 
  Nature 
  (Oc- 
  

   tober 
  aud 
  November, 
  1873), 
  bet 
  ween 
  

   Mr. 
  Casella 
  and 
  the 
  Messrs. 
  ISTe- 
  

   gretti 
  and 
  Zambra, 
  which 
  resulted 
  

   in 
  satisfying 
  the 
  editor 
  of 
  that 
  peri- 
  

   odical 
  that 
  " 
  the 
  whole 
  credit 
  of 
  the 
  

   double 
  bulb 
  belongs 
  to 
  jSegretti 
  and 
  

   Zambra." 
  This 
  statement, 
  although 
  

   conclusive 
  as 
  regards 
  the 
  contro- 
  

   versy 
  between 
  the 
  two 
  firms, 
  is 
  

   somewhat 
  too 
  positive 
  to 
  be 
  ac- 
  

   cepted 
  as 
  establishing 
  absolute 
  pri- 
  

   ority 
  of 
  invention, 
  since 
  the 
  use 
  of 
  a 
  double 
  cylinder 
  

   to 
  meet 
  pressure 
  error 
  was 
  made 
  sufficiently 
  familiar 
  by 
  

   Sir 
  William 
  Thomson's 
  paper 
  on 
  the 
  "Effect 
  of 
  pressure 
  

   in 
  lowering 
  the 
  freezing 
  point 
  of 
  water," 
  published 
  in 
  

   1850,* 
  in 
  which 
  his 
  "thermometer 
  was 
  entirely 
  inclosed 
  

   and 
  hermetically 
  sealed 
  in 
  a 
  glass 
  tube," 
  and 
  had 
  been 
  

   known 
  to 
  marine 
  investigators 
  at 
  least 
  as 
  early 
  as 
  1822, 
  

   when 
  Sir 
  Edward 
  Sabine 
  used 
  a 
  strong 
  iron 
  cylinder 
  for 
  

   this 
  purpose 
  ; 
  t 
  if 
  not, 
  as 
  has 
  been 
  supposed 
  by 
  Sir 
  

   "Wyville 
  Thomson 
  and 
  the 
  authors 
  of 
  the 
  Challenger 
  

   Narrative, 
  to 
  Sir 
  John 
  Boss, 
  in 
  1818. 
  

  

  The 
  Negretti-Zambra 
  deep-sea 
  thermometer, 
  as 
  at 
  

   present 
  used, 
  is 
  represented 
  by 
  Fig. 
  8. 
  Mercury 
  is 
  the 
  

   thermometric 
  fluid, 
  aud 
  the 
  bulb 
  is 
  about 
  2 
  inches 
  long 
  

   by 
  one-half 
  inch 
  in 
  diameter. 
  Just 
  beyond 
  the 
  bulb 
  

   the 
  tube 
  is 
  curved 
  like 
  the 
  Greek 
  ^ 
  laid 
  upon 
  its 
  side, 
  

   the 
  convexity 
  of 
  the 
  curve 
  being 
  widened 
  into 
  a 
  small 
  

   reservoir, 
  beyond 
  which 
  the 
  tube 
  is 
  constricted 
  in 
  a 
  particular 
  man- 
  

   ner. 
  At 
  the 
  upper 
  end 
  of 
  the 
  tube 
  is 
  a 
  small 
  pyriform 
  enlargment. 
  The 
  

  

  * 
  Proc. 
  R. 
  Soc. 
  Ed., 
  January 
  2, 
  1649, 
  and 
  January 
  1, 
  1850. 
  

   tPhil. 
  Trans. 
  R. 
  Soc, 
  vol. 
  cxiii 
  (April 
  17, 
  1823), 
  1823. 
  

  

  [G. 
  7.— 
  "Negretti- 
  

   Zambra 
  self-regis- 
  

   tering 
  min 
  i 
  m 
  n 
  m 
  

   deep-sea 
  thermom- 
  

   eter. 
  

  

  