﻿124 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Values 
  of 
  M 
  for 
  given 
  mean 
  annual 
  temperatures 
  are 
  as 
  follows 
  : 
  

  

  40°, 
  0.77; 
  41°, 
  0.79; 
  42°, 
  0.82; 
  43°, 
  0.85; 
  44°, 
  0.88; 
  45°, 
  0.91;. 
  

   46°, 
  0.94; 
  47°, 
  0.97; 
  48°, 
  1; 
  49°, 
  1.03; 
  50°, 
  1.07; 
  51°, 
  1.10; 
  52°, 
  

   1.14; 
  53°, 
  1.18; 
  54°, 
  1.22; 
  55°, 
  1.26; 
  56°, 
  1.30; 
  57°, 
  1.34; 
  58°, 
  1.39; 
  

   59°, 
  1.43; 
  60°, 
  1.47; 
  61°, 
  1.51. 
  

  

  In 
  a 
  table 
  on 
  page 
  149 
  of 
  the 
  Eeport 
  on 
  Forests 
  Mr 
  Vermeule 
  

   compares 
  observed 
  annual 
  evaporation 
  with 
  computed 
  annual 
  

   evaporation. 
  The 
  following 
  are 
  some 
  of 
  the 
  differences 
  which 
  

   appear 
  : 
  

  

  On 
  the 
  Genesee 
  river 
  the 
  observed 
  annual 
  evaporation 
  is 
  27.2 
  

   inches; 
  computed 
  annual 
  evaporation, 
  20.6 
  inches; 
  the 
  observed 
  

   annual 
  evaporation, 
  therefore, 
  is 
  6.6 
  inches, 
  or 
  32 
  per 
  cent 
  r 
  

   greater 
  than 
  the 
  estimated 
  annual 
  evaporation. 
  On 
  the 
  Mus- 
  

   conetcong 
  river 
  the 
  observed, 
  as 
  compared 
  with 
  the 
  computed 
  

   evaporation, 
  is 
  13 
  per 
  cent' 
  less; 
  on 
  the 
  Pequest 
  it 
  is 
  17 
  per 
  cent 
  

   less 
  ; 
  on 
  the 
  Paulinskill 
  it 
  is 
  14 
  per 
  cent 
  less 
  ; 
  on 
  the 
  Tohickon, 
  32 
  

   per 
  cent 
  less; 
  on 
  the 
  Neshaminv, 
  16 
  per 
  cent 
  less; 
  on 
  the 
  Perkio- 
  

   men, 
  17 
  per 
  cent 
  less; 
  on 
  the 
  Desplaines, 
  21 
  per 
  cent 
  greater; 
  on 
  

   the 
  Kansas, 
  15 
  per 
  cent 
  greater; 
  on 
  the 
  Upper 
  Hudson, 
  10 
  per 
  

   cent 
  greater 
  ; 
  on 
  Hemlock 
  lake, 
  18 
  per 
  cent 
  less 
  ; 
  on 
  the 
  Potomac, 
  

   17 
  per 
  cent 
  less 
  ; 
  on 
  the 
  Savannah, 
  13 
  per 
  cent 
  less. 
  For 
  the 
  rest 
  

   of 
  the 
  streams 
  cited 
  in 
  the 
  table 
  the 
  agreement 
  is 
  closer 
  than 
  this. 
  

  

  The 
  observed 
  annual 
  evaporation 
  is 
  32 
  per 
  cent 
  greater 
  than 
  

   the 
  computed 
  annual 
  evaporation 
  on 
  the 
  Genesee 
  river 
  and 
  32 
  per 
  

   cent 
  less 
  on 
  Tohickon 
  creek 
  — 
  a 
  range 
  of 
  64 
  per 
  cent. 
  Somewhat 
  

   similar 
  differences 
  are 
  found 
  on 
  other 
  streams 
  where 
  the 
  gaging* 
  

   are 
  approximately 
  right. 
  As 
  to 
  the 
  gagings 
  referred 
  to 
  in 
  the 
  

   Report 
  on 
  Forests, 
  the 
  writer 
  will 
  show 
  farther 
  on 
  in 
  this 
  paper 
  

   that 
  gagings 
  of 
  the 
  GeDesee 
  and 
  Hudson 
  rivers 
  are, 
  on 
  the 
  whole, 
  

   probably 
  the 
  best 
  thus 
  far 
  made 
  in 
  the 
  United 
  States. 
  Tohickon 
  r 
  

   Neshaminy 
  and 
  Perkiomen 
  creeks 
  have 
  been 
  gaged 
  by 
  Francis 
  

   weirs, 
  and 
  are, 
  with 
  the 
  exception 
  of 
  Tohickon, 
  considered 
  approx- 
  

   imately 
  right. 
  The 
  difficulty 
  here 
  is 
  probably 
  in 
  the 
  flood 
  flows. 
  

   The 
  writer 
  understands 
  that 
  Mr 
  Vermeule 
  used 
  the 
  Francis 
  

   formula 
  for 
  a 
  sharp-crested 
  weir. 
  The 
  gagings 
  of 
  Sudbury, 
  

  

  