﻿132 
  new 
  york 
  state 
  museum 
  

  

  Comparison 
  of 
  evaporations, 
  Hudson 
  and 
  genesee 
  rivers 
  

  

  Evaporation 
  Evaporation 
  

   of 
  Hudson 
  of 
  Genesee 
  

   Year 
  area 
  area 
  Difference 
  

  

  1890 
  21.79 
  26.32 
  —4.53 
  

  

  1891 
  22.40 
  24.07 
  —1.67 
  

  

  1892 
  20.79 
  26.27 
  —5.48 
  

  

  1893 
  20.27 
  25.95 
  —5.68 
  

  

  1894 
  22.00 
  28.41 
  —6.41 
  

  

  1895 
  : 
  19.21 
  24.33 
  —5.12 
  

  

  1896 
  21.58 
  27.88 
  —6.30 
  

  

  1897 
  20.32 
  25.01 
  —4.69 
  

  

  1898 
  20.65 
  27.37 
  —6.72 
  

  

  Mean 
  21.00 
  26.18 
  —5.18 
  

  

  It 
  will 
  be 
  noticed 
  that 
  in 
  the 
  first 
  of 
  the 
  two 
  preceding 
  tabula- 
  

   tions 
  for 
  the 
  Hudson 
  river, 
  there 
  are 
  eleven 
  years 
  included 
  and 
  

   that 
  the 
  average 
  of 
  the 
  rainfall 
  is 
  44.94 
  inches 
  ; 
  the 
  average 
  runoff 
  

   is 
  23.98 
  inches, 
  and 
  the 
  average 
  evaporation 
  is 
  20.96 
  inches. 
  The 
  

   Genesee 
  river, 
  on 
  the 
  contrary, 
  only 
  includes 
  nine 
  years, 
  from 
  

   1890 
  to 
  1898, 
  inclusive. 
  

  

  In 
  the 
  second 
  tabulation 
  the 
  years 
  1890-1898, 
  inclusive, 
  have 
  been 
  

   taken 
  for 
  not 
  only 
  the 
  Hudson 
  river, 
  but 
  also 
  for 
  the 
  Genesee, 
  for 
  

   purposes 
  of 
  comparison. 
  The 
  taking 
  of 
  the 
  Hudson 
  river 
  for 
  

   nine 
  years 
  instead 
  of 
  eleven 
  makes 
  a 
  slight 
  difference 
  in 
  the 
  means. 
  

   The 
  rainfall 
  is 
  45.27 
  inches; 
  the 
  runoff, 
  24.27 
  inches, 
  and 
  the 
  

   evaporation, 
  21 
  inches. 
  The 
  Hudson 
  river 
  table 
  is 
  not 
  worked 
  

   up 
  to 
  date, 
  although 
  the 
  data 
  are 
  at 
  hand, 
  for 
  the 
  reason 
  that 
  the 
  

   Genesee 
  river 
  data 
  do 
  not 
  extend 
  beyond 
  the 
  year 
  1898. 
  There 
  is 
  

   no 
  way, 
  therefore, 
  of 
  comparing 
  the 
  two 
  since 
  that 
  year. 
  1 
  

  

  Variation 
  in 
  weir 
  measurements. 
  The 
  writer 
  has 
  shown 
  2 
  the 
  

   considerable 
  variation 
  in 
  weir 
  measurements 
  due 
  to 
  the 
  difference 
  

   in 
  form 
  of 
  weir 
  alone. 
  So 
  great 
  are 
  these 
  that 
  any 
  conclusions 
  

   based 
  upon 
  the 
  data 
  of 
  sharp-crested 
  weirs 
  applied 
  to 
  other 
  forms 
  

  

  1 
  Partially 
  abstracted 
  from 
  paper, 
  Data 
  of 
  Stream 
  Flow 
  in 
  Relation 
  to 
  

   Forests, 
  by 
  Geo. 
  W. 
  Rafter. 
  Lecture 
  before 
  engineering 
  classes 
  of 
  Cor. 
  

   Uni., 
  Ap. 
  14, 
  1899. 
  Trans. 
  Assn. 
  of 
  Civ. 
  Engrs. 
  of 
  Cor. 
  Uni., 
  Vol. 
  VII, 
  1899. 
  

  

  2 
  On 
  the 
  Flow 
  of 
  Water 
  over 
  Dams: 
  Trans. 
  Am. 
  Soc. 
  C. 
  E., 
  Vol. 
  XLIV, 
  

   p. 
  220. 
  

  

  