﻿206 
  

  

  KEPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  [22] 
  

  

  been 
  resting* 
  in 
  its 
  cradle 
  under 
  the 
  guide-pulley, 
  is 
  sent 
  down 
  the 
  wire 
  

  

  and 
  capsizes 
  the 
  thermometer 
  by 
  striking 
  the 
  slip-hooks 
  and 
  forcing 
  them 
  

  

  pen, 
  when, 
  having 
  lost 
  its 
  support, 
  the 
  instrument 
  promptly 
  reverses, 
  

  

  as 
  shown 
  in 
  Fig. 
  14, 
  where 
  both 
  forms 
  are 
  represented 
  as 
  on 
  the 
  ascent. 
  

  

  "•All 
  buoyancy 
  being 
  destroyed 
  by 
  

   substituting 
  a 
  metal 
  case, 
  the 
  ther- 
  

   mometer 
  is 
  independent 
  of 
  the 
  motions 
  

   of 
  the 
  vessel, 
  either 
  from 
  rolling, 
  pitch- 
  

   ing, 
  or 
  drifting. 
  The 
  line 
  may 
  be 
  

   stopped 
  on 
  the 
  ascent 
  or 
  lowered 
  again 
  

   without 
  affecting 
  the 
  instrument 
  in 
  

   any 
  way. 
  We 
  have 
  taken 
  hundreds 
  

   of 
  temperatures 
  with 
  the 
  apparatus 
  

   described, 
  under 
  varying 
  conditions 
  

   of 
  wind 
  and 
  weather, 
  with 
  the 
  most 
  

   satisfactory 
  results."* 
  

  

  This 
  device 
  of 
  Mr. 
  Tanner's 
  is 
  the 
  

   first 
  instance 
  of 
  the 
  use 
  of 
  a 
  metallic 
  

   case 
  as 
  a 
  protective 
  and 
  reversing 
  ap- 
  

   paratus 
  that 
  I 
  find 
  record 
  of. 
  Although 
  

   invented 
  on 
  the 
  spur 
  of 
  the 
  moment, 
  

   and 
  to 
  meet 
  an 
  unforeseen 
  emergency, 
  

   it 
  was 
  found 
  to 
  answer 
  its 
  purpose 
  as 
  

   effectually, 
  if 
  with 
  less 
  elegance 
  of 
  de- 
  

   sign, 
  as 
  any 
  that 
  has 
  been 
  since 
  con- 
  

   trived. 
  

  

  The 
  next 
  improvement 
  was 
  the 
  in- 
  

   vention 
  of 
  Passed 
  Assistant 
  Engineer 
  

   William 
  L. 
  Bailie, 
  IT. 
  S. 
  Xavy, 
  at- 
  

   tached 
  to 
  the 
  Fish 
  Hawk, 
  and 
  appears 
  

   to 
  have 
  been 
  about 
  contemporaneous 
  

   with 
  the 
  invention 
  of 
  the 
  Magnaghi 
  

   case, 
  adopted 
  and 
  sold 
  by 
  Xegretti 
  

   and 
  Zambra 
  in 
  the 
  year 
  1S82. 
  It 
  con- 
  

   sists 
  essentially 
  of 
  a 
  propeller 
  and 
  slip- 
  

   hook, 
  inclosed 
  in 
  a 
  metal 
  case, 
  which 
  

   screws 
  to 
  the 
  upper 
  end 
  of 
  the 
  Tanner 
  

   case, 
  its 
  slip-hook 
  having 
  been 
  re- 
  

   moved 
  for 
  the 
  purpose. 
  By 
  this 
  de- 
  

   vice, 
  which 
  is 
  illustrated 
  by 
  Fig. 
  15, 
  

   the 
  thermometer 
  is 
  reversed 
  by 
  the 
  action 
  of 
  the 
  propeller, 
  " 
  bringing 
  

   the 
  screw 
  in 
  the 
  upper 
  part 
  of 
  the 
  spindle 
  into 
  action, 
  gradually 
  rais- 
  

   ing, 
  the 
  propeller 
  until 
  the 
  small 
  part 
  of 
  the 
  spindle 
  at 
  the 
  lower 
  end 
  

   allows 
  the 
  hook 
  to 
  open, 
  releasing 
  the 
  wire, 
  when 
  the 
  thermometer 
  

  

  * 
  Report 
  on 
  the 
  construction 
  and 
  work 
  in 
  I860 
  of 
  the 
  Fish 
  Commission 
  steamer 
  

   Fish 
  Hawk, 
  hy 
  Lieut. 
  Z. 
  L. 
  Tanner, 
  U. 
  S. 
  N., 
  commanding. 
  (In 
  Report 
  of 
  the 
  Com- 
  

   missioner, 
  1881, 
  pp. 
  32,26.) 
  

  

  Fig. 
  14.— 
  Sounding 
  machine, 
  with 
  Negetti 
  

   Zambra 
  deep-sea 
  thermometers 
  ascending. 
  

  

  