﻿HYDROLOGY 
  OP 
  NEW 
  YORK 
  331 
  

  

  each 
  experimental 
  weir 
  below 
  the 
  standard 
  weir, 
  and 
  observing 
  

   the 
  heads 
  synchronously 
  on 
  each. 
  In 
  these 
  experiments 
  a 
  steady 
  

   current 
  was 
  established 
  in 
  the 
  channel, 
  and 
  observations 
  of 
  the 
  

   known 
  value 
  passing 
  over 
  the 
  standard 
  weir 
  were 
  made, 
  which 
  

   volume 
  also 
  passed 
  over 
  the 
  weir 
  under 
  investigation, 
  lower 
  down. 
  

   If 
  we 
  let 
  H 
  and 
  h 
  denote, 
  respectively, 
  the 
  head 
  upon 
  the 
  

   standard 
  weir 
  and 
  upon 
  the 
  lower 
  weir, 
  L 
  and 
  I, 
  their 
  correspond- 
  

   ing 
  lengths, 
  and 
  M 
  and 
  m, 
  the 
  coefficients 
  of 
  discharge, 
  and 
  then, 
  

   adopting 
  provisionally 
  Formula 
  (1) 
  for 
  the 
  standard 
  weir 
  — 
  

  

  Q^MLH^^jT; 
  (32) 
  

  

  and 
  similarly 
  for 
  the 
  lower 
  weir 
  

  

  Q 
  = 
  mlh 
  V2^A 
  ( 
  S3 
  ) 
  

  

  Equating 
  these 
  two 
  values 
  of 
  Q, 
  we 
  have 
  

  

  MLII^-Ji 
  s/i^—mlh 
  ^/a'V 
  2^ 
  or 
  

   MLH 
  1 
  = 
  mlh 
  1 
  

   from 
  which 
  we 
  deduce 
  the 
  value 
  of 
  m: 
  

  

  or, 
  conversely 
  : 
  M 
  = 
  m 
  I 
  y- 
  I 
  x 
  ( 
  -ft 
  ) 
  

  

  As 
  already 
  stated, 
  Bazin's 
  preliminary 
  gaging 
  operations 
  gave, 
  

   once 
  for 
  all, 
  the 
  coefficient 
  M 
  for 
  the 
  standard 
  weir 
  for 
  each 
  

  

  value 
  of 
  H. 
  The 
  ratio 
  —r 
  which 
  is 
  very 
  nearly 
  unity, 
  remained 
  

   constant 
  for 
  all 
  experiments 
  of 
  any 
  one 
  series, 
  and, 
  therefore, 
  we 
  

   have 
  only 
  to 
  measure 
  the 
  heads 
  H 
  and 
  h 
  in 
  order 
  to 
  obtain 
  the 
  

   coefficient 
  m. 
  1 
  

  

  A 
  description 
  of 
  the 
  method 
  of 
  gaging 
  pursued 
  on 
  the 
  several 
  

   streams 
  is 
  not 
  given 
  at 
  length 
  here 
  because 
  it 
  may 
  be 
  found 
  in 
  

   full 
  detail 
  in 
  the 
  places 
  cited, 
  namely, 
  in 
  the 
  Keport 
  to 
  the 
  Board 
  

   of 
  Engineers 
  on 
  Deep 
  Waterways 
  and 
  in 
  the 
  paper 
  On 
  the 
  Flow 
  

   of 
  Water 
  Over 
  Dams, 
  to 
  either 
  of 
  which 
  reference 
  may 
  be 
  made. 
  

  

  Discharge 
  measurements 
  of 
  Genesee 
  river. 
  The 
  runoff 
  data 
  of 
  

   Genesee 
  river 
  for 
  the 
  water 
  years 
  1890-1898, 
  inclusive, 
  in 
  inches 
  

   on 
  the 
  catchment 
  area, 
  have 
  been 
  given 
  in 
  table 
  No. 
  43. 
  The 
  

  

  ! 
  On 
  the 
  Flow 
  of 
  Water 
  Over 
  Dams, 
  Trans. 
  Am. 
  Soc. 
  C. 
  E., 
  Vol. 
  XLIV, 
  pp. 
  

   220-398. 
  

  

  