﻿36 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  It 
  is 
  best 
  to 
  select 
  a 
  site 
  for 
  a 
  batching 
  establishmeDt 
  iu 
  time 
  of 
  

   extrcDie 
  drouglit, 
  aud 
  if 
  it 
  then 
  has 
  an 
  ample 
  su])ply 
  of 
  pure, 
  sweet 
  

   water 
  the 
  first 
  requisites 
  are 
  fulfilled. 
  It 
  is 
  well 
  also 
  to 
  visit 
  the 
  place 
  

   in 
  time 
  of 
  flood 
  and, 
  if 
  in 
  a 
  cold 
  climate, 
  in 
  severe 
  winter 
  weather, 
  to 
  

   learn 
  the 
  dangers 
  to 
  be 
  guarded 
  against 
  on 
  those 
  scores. 
  The 
  volume 
  

   of 
  water 
  necessary 
  will 
  depend 
  mainly 
  on 
  the 
  proposed 
  capacity 
  of 
  the 
  

   establishment, 
  the 
  temperature 
  of 
  the 
  water, 
  its 
  character 
  as 
  to 
  aeration^ 
  

   and 
  the 
  facilities 
  existing 
  for 
  the 
  aeration 
  and 
  repeated 
  use 
  of 
  the 
  water. 
  

   With 
  water 
  of 
  the 
  highest 
  quality 
  and 
  low 
  temperature, 
  and 
  with 
  unlim- 
  

   ited 
  facilities 
  for 
  aeration, 
  possibly 
  a 
  gallon 
  a 
  minute, 
  or 
  even 
  less, 
  can 
  

   be 
  made 
  to 
  answer 
  for 
  the 
  incubation 
  of 
  100,000 
  eggs 
  of 
  salmon. 
  As 
  

   the 
  temperature 
  rises 
  or 
  the 
  facilities 
  for 
  aeration 
  are 
  curtailed 
  a 
  larger 
  

   volume 
  becomes 
  necessary. 
  In 
  case 
  of 
  spring 
  water, 
  cooled 
  only 
  to 
  

   40° 
  and 
  aerated 
  only 
  by 
  exposure 
  to 
  air 
  in 
  a 
  pool 
  of 
  about 
  a 
  square 
  rod 
  

   surface, 
  with 
  no 
  facilities 
  in 
  the 
  house 
  for 
  aeration, 
  and 
  with 
  the 
  eggs 
  

   and 
  fry 
  crowded 
  in 
  the 
  troughs 
  at 
  the 
  rate 
  of 
  4,000 
  per 
  square 
  foot, 
  

   4 
  gallons 
  a 
  minute 
  is 
  the 
  least 
  that 
  can 
  be 
  allowed, 
  while 
  0, 
  8, 
  or 
  10 
  

   gallons 
  per 
  minute 
  are 
  better. 
  While 
  the 
  minimum 
  is, 
  as 
  stated 
  above, 
  

   possibly 
  less 
  than 
  a 
  gallon 
  a 
  minute, 
  it 
  is 
  not 
  advisable 
  to 
  trust 
  to 
  

   less 
  than 
  3 
  gallons 
  per 
  minute 
  for 
  each 
  100,000 
  eggs 
  under 
  the 
  most 
  

   favorable 
  circumstances. 
  

  

  If 
  the 
  water 
  supply 
  is 
  drawn 
  from 
  a 
  small 
  brook 
  or 
  spring, 
  it 
  is 
  neces- 
  

   sary 
  to 
  measure 
  the 
  volume 
  approximately, 
  which 
  is 
  easily 
  done, 
  in 
  the 
  

   following 
  manner: 
  With 
  a 
  wide 
  board 
  1 
  inch 
  thick, 
  having 
  a 
  smooth 
  

   inch 
  hole 
  bored 
  through 
  the 
  middle, 
  a 
  tight 
  dam 
  is 
  made 
  across 
  the 
  

   stream 
  so 
  that 
  all 
  the 
  water 
  will 
  have 
  to 
  flow 
  through 
  the 
  hole. 
  If 
  the 
  

   water 
  on 
  the 
  upper 
  side 
  rises 
  just 
  to 
  the 
  top 
  of 
  the 
  hole, 
  it 
  indicates 
  a 
  

   volume 
  of 
  2.3 
  gallons 
  per 
  minute; 
  a 
  rise 
  of 
  half 
  an 
  inch 
  above 
  the 
  top 
  

   of 
  the 
  hole 
  indicates 
  a 
  volume 
  of 
  3.5 
  gallons 
  per 
  minute; 
  2 
  inches 
  rise, 
  5 
  

   gallons 
  per 
  minute; 
  3 
  inches, 
  6 
  gallons 
  per 
  minute; 
  inches, 
  8 
  gallons 
  per 
  

   minute 
  ; 
  13 
  inches, 
  12 
  gallons 
  per 
  minute. 
  If 
  two 
  1-inch 
  holes 
  are 
  bored, 
  

   the 
  same 
  will, 
  of 
  course, 
  indicate 
  twice 
  the 
  volume. 
  The 
  volume 
  of 
  

   water 
  flowing 
  through 
  holes 
  of 
  diflerent 
  sizes 
  is 
  in 
  proportion 
  to 
  the 
  

   squares 
  of 
  their 
  diameters; 
  thus 
  a 
  2-inch 
  hole 
  permits 
  the 
  passage 
  of 
  

   four 
  times 
  as 
  much 
  as 
  a 
  1-inch 
  hole. 
  A 
  cylindrical 
  tube 
  whose 
  length 
  is 
  

   three 
  times 
  its 
  diameter 
  will 
  allow 
  29 
  per 
  cent 
  more 
  water 
  to 
  pass 
  than 
  

   a 
  hole 
  of 
  the 
  same 
  diameter 
  through 
  a 
  thin 
  plate 
  or 
  board. 
  

  

  SITE. 
  

  

  After 
  a 
  satisfactory 
  supply 
  of 
  water 
  is 
  found 
  a 
  site 
  for 
  the 
  hatching- 
  

   house 
  must 
  be 
  selected 
  that 
  affords 
  facilities 
  for 
  creating 
  a 
  head 
  of 
  

   water 
  to 
  provide 
  for 
  the 
  requisite 
  fall 
  into 
  and 
  through 
  the 
  troughs, 
  

   security 
  against 
  inundation, 
  security 
  against 
  too 
  much 
  freezing 
  if 
  in 
  a 
  

   cold 
  climate, 
  and, 
  finally, 
  general 
  safety 
  and 
  accessibibty. 
  The 
  fall 
  

   required 
  in 
  the 
  hatching-house 
  can 
  hardly 
  be 
  too 
  great. 
  The 
  minimum 
  

   is 
  as 
  low 
  as 
  3 
  inches, 
  but 
  only 
  under 
  the 
  most 
  favorable 
  circumstances 
  

  

  