﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  147 
  

  

  then 
  forced 
  underneath, 
  cutting 
  the 
  frame 
  and 
  contents 
  free, 
  the 
  

   box 
  and 
  contents 
  inverted, 
  and 
  a 
  bottom 
  of 
  copper, 
  dishing 
  slightly 
  

   to 
  a 
  common 
  center, 
  where 
  a 
  pipe 
  was 
  inserted 
  and 
  securely 
  sol- 
  

   dered, 
  and 
  to 
  which 
  a 
  perforated 
  guard 
  was 
  attached, 
  was 
  strongly 
  

   fastened 
  into 
  position 
  by 
  bending 
  the 
  copper 
  sides 
  over 
  the 
  edge 
  

   of 
  this 
  bottom 
  piece 
  and 
  securely 
  soldering. 
  

  

  These 
  three 
  boxes 
  were 
  then 
  carried 
  from 
  the 
  point 
  of 
  filling 
  

   to 
  the 
  drain-gage 
  lawn, 
  where 
  they 
  were 
  placed 
  carefully 
  in 
  posi- 
  

   tion, 
  their 
  surfaces 
  level 
  with 
  the 
  surrounding 
  ground 
  and 
  the 
  

   pipe 
  which 
  passed 
  from 
  their 
  bottom 
  carried 
  into 
  a 
  subterranean 
  

   alcove 
  built 
  below 
  them, 
  and 
  upon 
  the 
  arch 
  of 
  which 
  the 
  boxes 
  

   rested, 
  with 
  the 
  intervention 
  of 
  about 
  six 
  inches 
  of 
  soil. 
  These 
  

   alcoves 
  branched 
  from 
  a 
  pit 
  carefully 
  arched 
  and 
  to 
  which 
  admit- 
  

   tance 
  is 
  obtained 
  by 
  steps. 
  A 
  bottle 
  kept 
  under 
  each 
  drain 
  gage 
  

   and 
  to 
  which 
  the 
  pipe 
  leads 
  enables 
  us 
  to 
  collect 
  all 
  the 
  water 
  

   which 
  drains 
  through, 
  and 
  a 
  graduated 
  measure 
  enables 
  us 
  to 
  

   measure 
  this 
  water 
  in 
  thousandths 
  of 
  an 
  inch, 
  thus 
  making 
  a 
  

   ready 
  comparison 
  with 
  the 
  rainfall, 
  a 
  record 
  of 
  which 
  is 
  kept 
  by 
  

   one 
  of 
  Green's 
  eight-inch 
  gages 
  located 
  alongside. 
  

  

  In 
  order 
  to 
  estimate 
  the 
  drainage 
  from 
  different 
  kinds 
  of 
  soil, 
  

   these 
  gages 
  have 
  different 
  classes 
  of 
  surfaces. 
  On 
  the 
  surface 
  of 
  

   No. 
  1 
  is 
  a 
  heavy 
  sod 
  ; 
  of 
  No. 
  2 
  the 
  surface 
  is 
  bare 
  and 
  undisturbed 
  ; 
  

   while 
  of 
  No. 
  3 
  the 
  surface 
  is 
  kept 
  pulverized 
  during 
  the 
  open 
  sea- 
  

   son 
  by 
  frequent 
  stirring 
  with 
  a 
  trowel. 
  

  

  An 
  edging 
  of 
  hard 
  brass, 
  one 
  inch 
  high, 
  extends 
  around 
  the 
  top 
  

   of 
  the 
  frames, 
  accurately 
  defining 
  the 
  area. 
  Hence, 
  all 
  the 
  rain- 
  

   fall 
  over 
  the 
  area 
  is 
  compelled 
  to 
  enter 
  the 
  soil 
  and 
  by 
  measuring 
  

   the 
  amount 
  percolating, 
  we 
  can 
  account 
  for 
  the 
  balance 
  which 
  

   evaporates. 
  Having 
  the 
  three 
  gages 
  we 
  can 
  calculate 
  the 
  amount 
  

   of 
  water 
  evaporated 
  from 
  growing 
  sod, 
  from 
  a 
  bare 
  surface 
  and 
  

   from 
  a 
  stirred 
  surface, 
  respectively. 
  The 
  difference 
  between 
  the 
  

   precipitation 
  and 
  drainage 
  from 
  such 
  gages 
  is 
  taken 
  to 
  represent 
  

   the 
  evaporation 
  from 
  the 
  ground. 
  

  

  In 
  order 
  to 
  show 
  the 
  meteorological 
  conditions 
  existing 
  at 
  

   Geneva, 
  table 
  No. 
  32, 
  Precipitation 
  at 
  Geneva 
  Agricultural 
  Ex- 
  

   periment 
  Station 
  for 
  the 
  Water 
  Years 
  1883-1889, 
  Inclusive, 
  is 
  

   given. 
  This 
  table, 
  however, 
  while 
  apparently 
  a 
  table 
  of 
  precipi- 
  

   tation, 
  does 
  not 
  give 
  a 
  complete 
  record 
  of 
  precipitation 
  in 
  the 
  

   form 
  of 
  snow 
  and 
  is 
  somewhat 
  deficient 
  as 
  to 
  quantity 
  during 
  the 
  

   winter 
  months. 
  Nevertheless 
  there 
  is 
  a 
  tendency 
  to 
  very 
  low 
  

  

  