﻿[13] 
  REPORT 
  ON 
  THERMOMETERS. 
  197 
  

  

  these 
  instruments 
  answer 
  well 
  the 
  purpose 
  of 
  their 
  construction, 
  and 
  

   have, 
  in 
  fact, 
  been 
  the 
  means 
  by 
  which 
  most 
  of 
  the 
  best 
  modern 
  tem- 
  

   perature 
  observations 
  beneath 
  the 
  sea 
  have 
  been 
  made. 
  Now 
  that 
  the 
  

   small 
  aneurisms 
  near 
  the 
  bends 
  of 
  the 
  U 
  have 
  been 
  given 
  up 
  by 
  the 
  

   makers, 
  it 
  appears 
  that 
  the 
  pressure 
  error 
  may 
  be 
  safely 
  disregarded 
  

   in 
  practice 
  (excepting 
  at 
  very 
  great 
  depths, 
  when 
  Professor 
  Tait's 
  tables 
  

   will 
  be 
  found 
  useful), 
  and 
  that 
  the 
  laboratory 
  corrections, 
  under 
  ordi- 
  

   nary 
  atmospheric 
  pressures, 
  will 
  answer 
  every 
  practical 
  purpose. 
  

  

  This 
  form 
  of 
  deep-sea 
  thermometer, 
  under 
  its 
  present 
  name, 
  is 
  a 
  cu- 
  

   rious 
  example 
  of 
  re-invention 
  within 
  a 
  shorter 
  time 
  than 
  usual 
  after 
  the 
  

   original 
  publication 
  of 
  its 
  conception. 
  As 
  now 
  advertised 
  and 
  used, 
  it 
  

   is 
  commonly 
  supposed 
  to 
  be 
  the 
  invention 
  of 
  the 
  late 
  Dr. 
  W. 
  A. 
  Miller, 
  

   vice-president 
  of 
  the 
  Eoyal 
  Society 
  in 
  1869, 
  and 
  to 
  have 
  been 
  first 
  used 
  

   in 
  the 
  cruise 
  of 
  the 
  Porcupine 
  in 
  that 
  year. 
  The 
  invention 
  consisted, 
  

   as 
  has 
  been 
  already 
  said, 
  in 
  the 
  protection 
  of 
  the 
  larger 
  bulb 
  of 
  a 
  Sixe's 
  

   thermometer 
  by 
  another 
  cylindrical 
  glass 
  tube, 
  hermetically 
  sealed 
  

   about 
  it 
  and 
  partly 
  filled 
  with 
  alcohol. 
  There 
  is 
  no 
  reason 
  to 
  doubt 
  that 
  

   Dr. 
  Miller 
  promulgated 
  his 
  invention 
  in 
  good 
  faith, 
  but 
  there 
  is 
  also 
  no 
  

   reason 
  to 
  doubt 
  that 
  an 
  exactly 
  similar, 
  and 
  perhaps 
  more 
  effective, 
  in- 
  

   strument 
  of 
  the 
  same 
  sort 
  had 
  been 
  made 
  so 
  early 
  as 
  1857. 
  

  

  In 
  that 
  year 
  the 
  late 
  Admiral 
  Fitzroy, 
  acting 
  under 
  a 
  suggestion 
  by 
  

   Mr. 
  Glaisher, 
  requested 
  Messrs. 
  Negretti 
  and 
  Zambra 
  to 
  endeavor 
  to 
  

   protect 
  the 
  bulb 
  of 
  Sixe's 
  thermometer 
  against 
  sea 
  pressures, 
  which 
  was 
  

   successfully 
  accomplished 
  by 
  inclosing 
  the 
  bulb 
  in 
  an 
  air-tight 
  glass 
  shield, 
  

   nearly 
  filled 
  with 
  mercury 
  to 
  promote 
  conduction 
  of 
  heat.* 
  Some 
  fifty 
  

   of 
  these 
  instruments 
  were 
  made 
  for 
  and 
  purchased 
  by 
  the* 
  hydrographic 
  

   office 
  of 
  the 
  admiralty. 
  It 
  appears 
  to 
  be 
  certain 
  that 
  these 
  instruments 
  

   were 
  used 
  by 
  Captain 
  Pullen, 
  in 
  the 
  voyage 
  of 
  the 
  Cyclops, 
  which 
  be- 
  

   gan 
  in 
  1857. 
  Forty-one 
  important 
  observations 
  were 
  taken 
  in 
  the 
  North 
  

   and 
  South 
  Atlantic, 
  the 
  Indian 
  Ocean, 
  and 
  the 
  Ked 
  Sea, 
  at 
  depths 
  from 
  

   2,400 
  to 
  16,000 
  feet, 
  with 
  "Negretti 
  and 
  Zain 
  bra's 
  protected 
  Sixe's 
  ther- 
  

   mometers."t 
  Pullen 
  noted 
  that 
  the 
  maximum 
  index 
  often 
  shifted, 
  indi- 
  

   cating 
  that 
  he 
  used 
  the 
  instrument 
  provided 
  with 
  both 
  maximum 
  and 
  

   minimum 
  scales. 
  

  

  From 
  an 
  account 
  published 
  by 
  the 
  makers 
  in 
  1864,$ 
  I 
  infer 
  that 
  the 
  

   original 
  form 
  was 
  precisely 
  like 
  Sixe's 
  thermometer§ 
  with 
  a 
  double 
  curve, 
  

  

  * 
  Meteorological 
  Papers, 
  No. 
  1, 
  July 
  5, 
  1857. 
  

  

  t 
  J. 
  Prestwich, 
  on 
  Submarine 
  Temperatures, 
  &c. 
  Phil. 
  Trans. 
  Roy. 
  Soc. 
  Vol. 
  cIxt 
  

   (1875), 
  p. 
  608. 
  

  

  JA 
  Treatise 
  on 
  Meteorological 
  Instruments, 
  Negretti 
  and 
  Zambra. 
  London, 
  

   1864. 
  

  

  $ 
  Invented 
  by 
  James 
  Six 
  (or 
  Sixe) 
  of 
  Canterbury 
  (or 
  Colchester), 
  in 
  1782. 
  In 
  the 
  

   original 
  account 
  (Trans. 
  R. 
  S., 
  vol. 
  lxxii, 
  p. 
  72, 
  1782) 
  Mr. 
  Six 
  states 
  that 
  "our 
  ther- 
  

   mometer 
  resembles 
  in 
  some 
  respects 
  those 
  of 
  M. 
  Bernoulli 
  and 
  Lord 
  Charles 
  Caven- 
  

   dish," 
  the 
  invention 
  claimed 
  consisting 
  in 
  the 
  mode 
  of 
  registration. 
  A 
  thread 
  of 
  glass 
  

   was 
  at 
  first 
  used, 
  instead 
  of 
  a 
  hair, 
  to 
  hold 
  the 
  index 
  in 
  place. 
  

  

  