﻿MANUAL 
  OF 
  FISH-CULTURE. 
  

  

  55 
  

  

  of 
  the 
  trough, 
  hinged 
  to 
  its 
  sides, 
  and, 
  when 
  closed, 
  assuming 
  the 
  form 
  

   of 
  a 
  roof 
  at 
  an 
  angle 
  of 
  -45°, 
  were 
  finally 
  adopted. 
  These 
  covers 
  are 
  

   made 
  of 
  thin 
  boards, 
  g 
  inch 
  thick, 
  sawed 
  in 
  narrow 
  pieces, 
  which 
  are 
  

   put 
  together 
  so 
  as 
  to 
  leave 
  in 
  each 
  corner 
  two 
  cracks 
  open 
  ^ 
  inch 
  wide 
  

   for 
  the 
  admission 
  of 
  light 
  when 
  the 
  covers 
  are 
  closed. 
  When 
  open 
  they 
  

   may 
  be 
  fixed 
  in 
  an 
  upright 
  position, 
  thus 
  increasing 
  the 
  height 
  of 
  the 
  

   sides 
  and 
  guarding 
  against 
  the 
  loss 
  of 
  fish 
  by 
  jumping 
  out. 
  

  

  Tig.l 
  

  

  B 
  

  

  s\\^- 
  

  

  Fig. 
  2. 
  

  

  

  Fig.3. 
  

  

  Fig. 
  4. 
  

  

  rig.5. 
  

  

  Troughs 
  arranged 
  for 
  Rearing. 
  

  

  

  Fig. 
  1, 
  plan. 
  Fig. 
  2, 
  longitudinal 
  section. 
  Fig. 
  3, 
  cross-section 
  near 
  foot 
  of 
  tiougli. 
  Fif;. 
  4, 
  inlet, 
  

   with 
  rocking 
  gate. 
  Fig. 
  5, 
  elevation 
  of 
  lower 
  end. 
  

  

  a, 
  supply-trough. 
  

   6, 
  screen. 
  

  

  c, 
  rocking 
  gate. 
  

  

  d, 
  supply-pipe. 
  

  

  ?, 
  water-'board 
  (to 
  spread 
  the 
  water 
  and 
  throw 
  it 
  down). 
  

   /, 
  fish-trough. 
  

  

  (/, 
  gnpe, 
  to 
  prevent 
  spreading 
  of 
  sides. 
  

   h, 
  outlet 
  screen. 
  

  

  i, 
  hollow 
  outlet 
  plug. 
  

  

  _;, 
  down-spout. 
  

  

  A:, 
  supports. 
  

  

  I, 
  cover. 
  

   )H, 
  cover 
  open 
  (hanging). 
  

   «, 
  cover 
  open 
  (upright), 
  

   jt), 
  cover 
  closed. 
  

   </, 
  end 
  boards 
  (closing 
  aperture). 
  

  

  Water 
  is 
  furnished 
  through 
  rubber 
  or 
  wooden 
  pipes 
  % 
  inch 
  in 
  diame- 
  

   ter, 
  and 
  the 
  bore 
  of 
  the 
  hollow 
  plug 
  at 
  the 
  outlet 
  is 
  \\ 
  inch 
  or 
  larger. 
  

   The 
  inflow 
  is 
  regulated 
  by 
  an 
  oscillating 
  or 
  rocking 
  gate, 
  which 
  is 
  set 
  

   to 
  admit 
  the 
  desired 
  volume 
  of 
  water. 
  The 
  trough 
  is 
  set 
  with 
  the 
  

   upper 
  eud 
  an 
  inch 
  or 
  two 
  higher 
  than 
  the 
  other, 
  to 
  facilitate 
  cleaning 
  

   out, 
  and 
  the 
  water 
  is 
  kept 
  during 
  the 
  summer 
  about 
  4 
  inches 
  deep 
  at 
  

   the 
  lower 
  end. 
  

  

  