﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  611 
  

  

  The 
  following 
  are 
  the 
  approximate 
  quantities 
  of 
  permanent 
  

   power 
  in 
  gross 
  horsepower 
  which 
  may 
  be 
  realized 
  at 
  Rochester 
  

   from 
  a 
  flow 
  of 
  1000 
  cubic 
  feet 
  per 
  second 
  : 
  Gross 
  

  

  horsepower 
  

  

  Johnson 
  and 
  Seymour 
  raceway 
  1,081 
  

  

  Rochester, 
  Carroll 
  and 
  Fitzhugh 
  raceway 
  1,081 
  

  

  Upper 
  falls 
  10,448 
  

  

  Middle 
  falls 
  3,180 
  

  

  Lower 
  falls 
  10,903 
  

  

  Undeveloped 
  1,931 
  

  

  Total 
  ~~ 
  28,624 
  

  

  The 
  total 
  theoretical 
  power 
  is, 
  as 
  stated 
  on 
  a 
  previous 
  page, 
  

   28,840 
  gross 
  horsepower, 
  which 
  under 
  the 
  conditions 
  of 
  1904,, 
  

   may 
  be 
  taken 
  at 
  over 
  31,000 
  gross 
  horsepower. 
  

  

  Why 
  the 
  gross 
  horsepower 
  has 
  been 
  adopted 
  as 
  the 
  unit 
  of 
  power. 
  

   The 
  unit 
  of 
  power 
  adopted 
  is 
  the 
  gross 
  horsepower 
  — 
  that 
  is, 
  the 
  

   theoretical 
  power 
  produced 
  by 
  a 
  given 
  quantity 
  of 
  water 
  falling 
  

   through 
  a 
  given 
  space. 
  The 
  reasons 
  for 
  adopting 
  this 
  unit 
  are 
  as 
  

   follows 
  : 
  Water 
  is 
  easy 
  to 
  measure, 
  while 
  the 
  actual 
  power 
  pro- 
  

   duced 
  by 
  water 
  wheels 
  — 
  that 
  is, 
  the 
  net 
  power 
  — 
  is 
  difficult 
  to 
  

   measure. 
  Again, 
  the 
  efficiency 
  of 
  water 
  wheels 
  varies 
  greatly, 
  the 
  

   best 
  modern 
  wheels 
  yielding 
  from 
  about 
  70 
  per 
  cent 
  to 
  75 
  per 
  

   cent 
  of 
  the 
  theoretical 
  power 
  of 
  the 
  water. 
  On 
  the 
  other 
  hand, 
  

   many 
  of 
  the 
  cheaper 
  wheels 
  do 
  not 
  yield 
  more 
  than 
  40 
  per 
  cent 
  

   to 
  50 
  per 
  cent. 
  With 
  the 
  gross 
  horsepower 
  adopted 
  as 
  the 
  unit/ 
  

   the 
  onus 
  of 
  getting 
  the 
  largest 
  possible 
  net 
  power 
  out 
  of 
  the 
  given 
  

   quantity 
  of 
  water 
  is 
  thrown 
  where 
  it 
  belongs, 
  namely, 
  on 
  the 
  user. 
  

   On 
  aDy 
  other 
  basis 
  there 
  would 
  be 
  an 
  uncertainty 
  as 
  to 
  the 
  quan- 
  

   tity 
  of 
  water 
  contracted 
  for, 
  with 
  its 
  attendant 
  disputes. 
  

  

  Quantity 
  of 
  water 
  per 
  gross 
  horsepower. 
  The 
  following 
  are 
  the 
  

   quantities 
  of 
  water 
  per 
  gross 
  horsepower 
  on 
  the 
  several 
  developed 
  

   powers 
  at 
  Rochester 
  : 
  Quantity 
  

  

  of 
  water 
  in 
  

   cubic 
  feet 
  

   per 
  second 
  

   Head 
  per 
  gross 
  

  

  Name 
  of 
  dam 
  in 
  feet 
  horsepower 
  

  

  Johnson 
  and 
  Seymour 
  19 
  . 
  4630 
  

  

  Upper 
  falls 
  92 
  0.0957 
  

  

  Middle 
  falls 
  28 
  0.3140 
  

  

  Lower 
  falls 
  96 
  0.0917 
  

  

  