﻿128 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  The 
  cross-tanks 
  are 
  in 
  steps, 
  like 
  a 
  flight 
  of 
  stairs, 
  which 
  accounts 
  

   for 
  the 
  unequal 
  lengths 
  of 
  the 
  supply-troughs. 
  Each 
  has 
  an 
  overflow 
  

   in 
  the 
  center, 
  over 
  which 
  a 
  small 
  amount 
  of 
  water 
  is 
  kept 
  running, 
  so 
  

   that 
  the 
  attendant 
  can 
  see 
  at 
  a 
  glance 
  that 
  all 
  of 
  the 
  troughs 
  are 
  full. 
  

   Screens 
  are 
  interposed 
  at 
  such 
  places 
  in 
  the 
  cross-tanks 
  that 
  the 
  fry 
  

   discharged 
  into 
  them 
  through 
  the 
  waste-troughs 
  can 
  not 
  enter 
  the 
  oppo- 
  

   site 
  supply-troughs, 
  but 
  will 
  float 
  with 
  the 
  overflow 
  successively 
  into 
  

   the 
  lower 
  cross-tanks 
  down 
  to 
  the 
  fry-collectiiig 
  tanks. 
  

  

  The 
  fry-collecting 
  tanks, 
  one 
  for 
  each 
  battery, 
  are 
  connected 
  with 
  the 
  

   main 
  collecting 
  tanks 
  by 
  means 
  of 
  2-inch 
  gas-pipe, 
  fltted 
  with 
  valves, 
  

   passing 
  under 
  the 
  floor 
  of 
  the 
  hatchery. 
  The 
  main 
  tanks, 
  eight 
  in 
  

   number, 
  are 
  3 
  feet 
  wide, 
  10 
  feet 
  long, 
  and 
  2 
  feet 
  deep 
  ; 
  in 
  these 
  the 
  fry 
  

   are 
  retained 
  until 
  dipped 
  out 
  for 
  shipment 
  or 
  planting. 
  

  

  The 
  only 
  marked 
  difterence 
  between 
  the 
  method 
  of 
  operating 
  the 
  jars 
  

   at 
  Put-in 
  Bay 
  and 
  other 
  stations 
  is 
  the 
  use 
  of 
  a 
  finch 
  iron 
  gas-pipe, 
  

   instead 
  of 
  a 
  glass 
  tube, 
  for 
  supplying 
  the 
  jars 
  with 
  water, 
  and 
  the 
  addi- 
  

   tion 
  of 
  a 
  tin 
  cone, 
  inches 
  long 
  and 
  1 
  inch 
  in 
  diameter 
  at 
  the 
  lower 
  

   end, 
  which 
  is 
  soldered 
  to 
  the 
  end 
  of 
  the 
  iron 
  pipe 
  and 
  reaches 
  within 
  

   one-eighth 
  inch 
  of 
  tlie 
  bottom 
  of 
  the 
  jar. 
  The 
  tube 
  is 
  held 
  in 
  place 
  by 
  

   an 
  iron 
  bracket, 
  fastened 
  to 
  the 
  supply-trough 
  and 
  held 
  by 
  a 
  thumb- 
  

   screw. 
  The 
  cone 
  has 
  the 
  eftect 
  of 
  spreading 
  the 
  water 
  and 
  giving 
  an 
  

   easier 
  and 
  more 
  thorough 
  motion 
  to 
  the 
  eggs 
  than 
  can 
  be 
  obtained 
  with 
  

   a 
  straight 
  tube. 
  

  

  At 
  Put-in 
  Bay 
  the 
  water 
  passes 
  through 
  eight 
  rows 
  of 
  jars, 
  and 
  the 
  

   fact 
  that 
  the 
  eggs 
  in 
  the 
  lower 
  rows 
  of 
  jars 
  are 
  just 
  as 
  good 
  as 
  those 
  

   in 
  the 
  upper 
  rows 
  is 
  proof 
  of 
  the 
  practicability 
  of 
  the 
  plan. 
  

  

  The 
  jars 
  require 
  6 
  quarts 
  of 
  water 
  per 
  minute 
  to 
  each 
  jar 
  on 
  the 
  top 
  

   row, 
  this 
  amount 
  again 
  supplying 
  the 
  successive 
  tiers 
  of 
  jars 
  on 
  the 
  

   shelves 
  below. 
  If 
  more 
  jars 
  are 
  placed 
  on 
  the 
  lower 
  shelves 
  than 
  on 
  

   the 
  top 
  one, 
  a 
  greater 
  quantity 
  of 
  water 
  must 
  necessarily 
  be 
  added, 
  

   equal 
  to 
  (3 
  quarts 
  of 
  water 
  to 
  each 
  jar. 
  

  

  The 
  temperature 
  of 
  the 
  water 
  must, 
  of 
  course, 
  with 
  the 
  large 
  quan- 
  

   tities 
  used, 
  be 
  what 
  nature 
  makes 
  it, 
  but 
  if 
  much 
  above 
  50° 
  F. 
  good 
  

   results 
  can 
  not 
  be 
  expected 
  with 
  whitefish 
  eggs. 
  When 
  the 
  work 
  

   begins, 
  early 
  in 
  November, 
  the 
  temperature 
  of 
  the 
  water 
  in 
  Lake 
  Erie 
  

   is 
  from 
  40° 
  to 
  50° 
  P., 
  while 
  late 
  in 
  the 
  month 
  it 
  is 
  generally 
  about 
  35° 
  

   to 
  38°. 
  As 
  soon 
  as 
  the 
  lake 
  freezes 
  over, 
  or 
  ice 
  in 
  any 
  considerable 
  

   quantity 
  forms, 
  the 
  temperature 
  of 
  the 
  water 
  as 
  it 
  passes 
  through 
  the 
  

   jars 
  remains 
  very 
  uniform 
  at 
  32J°. 
  When 
  the 
  ice 
  goes 
  out, 
  which 
  is 
  

   generally 
  about 
  the 
  middle 
  of 
  March, 
  it 
  rises 
  slowly, 
  and 
  when 
  the 
  fiy 
  

   begin 
  to 
  hatch, 
  the 
  latter 
  part 
  of 
  the 
  mouth, 
  it 
  is 
  generally 
  up 
  to 
  about 
  

   33° 
  or 
  34°. 
  

  

  The 
  jars, 
  tubes, 
  troughs, 
  etc., 
  should 
  be 
  kept 
  scrupulously 
  clean. 
  

   The 
  usual 
  coating 
  for 
  the 
  inside 
  of 
  troughs 
  and 
  tanks 
  is 
  asphaltum 
  

   varnish, 
  but 
  a 
  mixture 
  of 
  coal 
  tar 
  and 
  turpentine 
  has 
  proved 
  an 
  excel- 
  

   lent 
  substitute. 
  For 
  the 
  first 
  coat 
  on 
  new 
  wood 
  equal 
  parts 
  of 
  each 
  

   are 
  employed; 
  for 
  the 
  second 
  and 
  third 
  coats 
  one 
  third 
  turpentine 
  and 
  

  

  