﻿628 
  

  

  F. 
  W. 
  Very— 
  Solar 
  Radiation. 
  

  

  on 
  the 
  mountain 
  by 
  variations 
  of 
  aqueous 
  vapor 
  pressure 
  be- 
  

   tween 
  \\ 
  and 
  15 
  mra 
  . 
  Consequently, 
  the 
  aqueous 
  absorption 
  has 
  

   already 
  produced 
  very 
  nearly 
  its 
  maximum 
  effect 
  in 
  the 
  upper 
  

   region 
  of 
  the 
  isothermal 
  layer, 
  and 
  the 
  water 
  vapor 
  near 
  the 
  

   level 
  of 
  the 
  mountain 
  top 
  is 
  not 
  in 
  a 
  condition 
  to 
  produce 
  much 
  

   new 
  depletion. 
  

  

  Fig. 
  2. 
  

  

  4 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  + 
  

  

  + 
  

  

  

  4 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  3 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  1 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  i 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  10 
  12 
  14-mm. 
  

  

  Fig. 
  2. 
  Abscissae 
  = 
  pressure 
  of 
  aqueous 
  vapor. 
  Ordinates 
  r= 
  values 
  of 
  A 
  

   by 
  preliminary 
  chart. 
  

  

  The 
  case 
  is 
  different 
  at 
  sea-level, 
  where 
  a 
  much 
  more 
  promi- 
  

   nent 
  vapor 
  factor 
  is 
  required. 
  The 
  vapor 
  of 
  the 
  lower 
  air, 
  by 
  

   its 
  condensation 
  T 
  products 
  on 
  the 
  dust 
  particles 
  out 
  of 
  which 
  the 
  

   haze 
  which 
  gives 
  to 
  distant 
  hills 
  and 
  mountains 
  their 
  blue 
  tint 
  

   takes 
  its 
  birth, 
  has 
  added 
  a 
  new 
  sort 
  of 
  depletion 
  in 
  the 
  lower 
  

   air 
  layers 
  which 
  is 
  very 
  much 
  less 
  effective 
  in 
  the 
  purer 
  air 
  

   above 
  the 
  mountain 
  top 
  (altitude 
  = 
  1780 
  meters). 
  The 
  average 
  

   values 
  of 
  A 
  in 
  the 
  examples 
  given 
  here 
  are 
  : 
  

  

  Washington 
  (5 
  days), 
  A 
  = 
  3*138 
  ± 
  '105. 
  

   Mt. 
  Wilson 
  (3 
  days), 
  A 
  = 
  3-589 
  ± 
  -017. 
  

  

  