﻿14 
  WATEE-POWER 
  DEVELOPMENT 
  IN 
  THE 
  MISSISSIPPI. 
  

  

  bed 
  of 
  the 
  river 
  and 
  is 
  flanked 
  by 
  the 
  tail-race 
  or 
  tail-bay, 
  an 
  impor- 
  

   tant 
  feature 
  for 
  our 
  consideration. 
  Between 
  the 
  head-bay 
  and 
  the 
  

   tail-race 
  intervene 
  the 
  turbines 
  or 
  power 
  units, 
  of 
  which 
  there 
  are 
  now 
  

  

  15 
  installed 
  and 
  15 
  more 
  in 
  contemplation. 
  These 
  are 
  arranged 
  in 
  a 
  

   single 
  linear 
  series 
  from 
  the 
  upper 
  to 
  the 
  lower 
  ends 
  of 
  the 
  house. 
  

  

  The 
  water 
  from 
  the 
  head 
  bay 
  is 
  admitted 
  to 
  each 
  turbine 
  through 
  

   four 
  gates, 
  each 
  22 
  feet 
  high 
  b}" 
  7 
  feet 
  6 
  inches 
  wide, 
  the 
  opening 
  

   being 
  protected 
  by 
  coarse 
  screens 
  or 
  iron 
  gratings, 
  which 
  exclude 
  the 
  

   passage 
  of 
  large 
  drift, 
  but 
  are 
  not 
  fine 
  enough 
  to 
  prevent 
  the 
  passage 
  

   of 
  any 
  but 
  the 
  largest 
  fish; 
  the 
  openings 
  between 
  bars 
  of 
  the 
  grat- 
  

   ings 
  are 
  6 
  by 
  23 
  inches. 
  The 
  four 
  intake 
  passageways 
  are 
  of 
  a 
  

   special 
  design 
  and 
  converge 
  into 
  a 
  single 
  largo 
  scroU 
  chamber 
  39 
  feet 
  

   in 
  diameter 
  around 
  the 
  turbine. 
  Other 
  gates 
  or 
  guide 
  vanes 
  at 
  this 
  

   place 
  control 
  the 
  passage 
  of 
  water 
  into 
  the 
  turbine 
  chamber, 
  whence, 
  

   after 
  setting 
  the 
  turbines 
  in 
  motion, 
  the 
  water 
  passes 
  down 
  through 
  

   the 
  enlarging 
  draft 
  chamber 
  out 
  into 
  the 
  tail-bay 
  below. 
  The 
  draft 
  

   chamber 
  is 
  circular 
  at 
  its 
  upper 
  end 
  just 
  below 
  the 
  turbme, 
  where 
  it 
  

   is 
  15 
  feet 
  in 
  diameter, 
  or 
  about 
  2 
  feet 
  greater 
  than 
  the 
  diameter 
  of 
  the 
  

   water 
  passage 
  through 
  the 
  turbines. 
  At 
  once, 
  however, 
  it 
  begins 
  

   to 
  enlarge 
  in 
  diameter 
  and 
  take 
  a 
  curved 
  form 
  by 
  which 
  it 
  changes 
  

   direction 
  from 
  the 
  vertical 
  to 
  the 
  horizontal 
  and 
  changes 
  from 
  a 
  cir- 
  

   cular 
  to 
  an 
  oblong 
  shape 
  in 
  cross 
  section. 
  The 
  outer 
  openings 
  of 
  the 
  

   draft 
  tube 
  below 
  are 
  22 
  feet 
  8 
  inches 
  in 
  vertical 
  diameter 
  and 
  40 
  feet 
  

   2 
  inches 
  in 
  horizontal 
  diameter. 
  The 
  bottom 
  of 
  these 
  openings 
  and 
  

   the 
  bottom 
  of 
  the 
  tail-race 
  is 
  about 
  25 
  feet 
  below 
  the 
  bottom 
  of 
  the 
  

   Mississippi. 
  

  

  Between 
  the 
  head-bay 
  and 
  the 
  tail-race 
  there 
  is 
  normally 
  a 
  head 
  of 
  

   32 
  feet. 
  It 
  is 
  calculated 
  that 
  the 
  velocity 
  of 
  the 
  water 
  at 
  the 
  top 
  of 
  

   the 
  draft 
  tube, 
  immediately 
  under 
  the 
  turbine, 
  will 
  normally 
  be 
  14 
  

   feet 
  per 
  second, 
  or 
  9 
  miles 
  per 
  hour, 
  while 
  at 
  the 
  point 
  of 
  discharge 
  

   into 
  the 
  tail-race 
  it 
  will 
  be 
  4 
  feet 
  per 
  second, 
  or 
  less 
  than 
  3 
  miles 
  per 
  

   hour. 
  The 
  water 
  in 
  the 
  tail-race 
  itself 
  may 
  have 
  a 
  greater 
  velocity. 
  

  

  It 
  has 
  been 
  complained 
  that 
  many 
  fish 
  are 
  destroyed 
  by 
  the 
  tur- 
  

   bines. 
  It 
  is 
  possible 
  that 
  descent 
  through 
  the 
  turbines 
  would 
  be 
  

   fatal, 
  but 
  it 
  is 
  scarcely 
  conceivable 
  that 
  fish 
  in 
  course 
  of 
  ascent 
  

   would 
  reach 
  the 
  turbines. 
  It 
  is 
  to 
  be 
  remembered 
  that 
  the 
  water 
  

   passes 
  the 
  turbines 
  in 
  course 
  of 
  a 
  vertical 
  descent 
  of 
  32 
  to 
  40 
  feet 
  

   with 
  greatest 
  velocity 
  where 
  the 
  turbines 
  intervene. 
  It 
  is 
  hardly 
  

   possible 
  that 
  fish 
  would 
  successfully 
  breast 
  a 
  vertical 
  current 
  of 
  such 
  

   force. 
  It 
  is 
  not 
  generally 
  the 
  swiftest 
  fish 
  that 
  seek 
  the 
  darkest 
  

   passageways. 
  The 
  blades 
  or 
  buckets 
  of 
  the 
  turbines, 
  of 
  course, 
  

   though 
  revolving 
  at 
  high 
  speed, 
  are 
  not 
  slashing 
  through 
  the 
  water 
  

   as 
  the 
  uninitiated 
  might 
  suppose, 
  but 
  are 
  driven 
  before 
  the 
  water. 
  

   Assuming, 
  therefore, 
  that 
  a 
  fish 
  could 
  make 
  the 
  tortuous 
  passage 
  

   from 
  tail-race 
  to 
  head-bay 
  against 
  the 
  velocity 
  of 
  the 
  water, 
  the 
  tur- 
  

  

  