﻿F. 
  W. 
  Very 
  — 
  Solar 
  Radiation. 
  

  

  623 
  

  

  Aqueous 
  vapor 
  between 
  l*5 
  min 
  and 
  4'5 
  mm 
  , 
  or 
  about 
  3 
  mm 
  . 
  

  

  

  Date. 
  

  

  No. 
  of 
  

   Obs. 
  

  

  Aq. 
  mm. 
  

  

  s 
  from 
  

  

  to 
  

  

  Mean 
  A. 
  

  

  At 
  mean 
  

  

  solar 
  

   distance. 
  

  

  1905 
  

  

  June 
  6 
  

  

  24 
  

  

  1-91 
  

  

  2-17 
  

  

  0*83 
  

  

  2-774 
  

  

  2- 
  

  

  845 
  

  

  

  " 
  14 
  

  

  28 
  

  

  2-30 
  

  

  3-25 
  

  

  0-83 
  

  

  3-023 
  

  

  3 
  

  

  106 
  

  

  

  " 
  20 
  

  

  12 
  

  

  3-96 
  

  

  1-86- 
  

  

  0'90 
  

  

  2-989 
  

  

  3 
  

  

  073 
  

  

  

  " 
  23 
  

  

  16 
  

  

  4-31 
  

  

  2-88 
  

  

  0-85 
  

  

  3*335 
  

  

  3 
  

  

  430 
  

  

  

  July 
  19 
  

  

  14 
  

  

  2-68 
  

  

  2-08 
  

  

  0-93 
  

  

  2-922 
  

  

  3 
  

  

  002 
  

  

  

  " 
  21 
  

  

  16 
  

  

  4-28 
  

  

  2-08 
  

  

  0*86 
  

  

  3-127 
  

  

  3 
  

  

  210 
  

  

  

  Oct. 
  26 
  

  

  10 
  

  

  3-38 
  

  

  2*64 
  

  

  1-27 
  

  

  3-333 
  

  

  3 
  

  

  280 
  

  

  1906 
  

  

  May 
  17 
  

  

  16 
  

  

  4-19 
  

  

  2-17 
  

  

  0-84 
  

  

  2-994 
  

  

  3 
  

  

  053 
  

  

  

  " 
  29 
  

  

  17 
  

  

  3*74 
  

  

  3*03 
  

  

  0-97 
  

  

  3-312 
  

  

  3- 
  

  

  389 
  

  

  

  " 
  30 
  

  

  17 
  

  

  4-46 
  

  

  3'19 
  

  

  0*88 
  

  

  3-298 
  

  

  3 
  

  

  376 
  

  

  

  June 
  7 
  

  

  20 
  

  

  4-12 
  

  

  3-08 
  

  

  0-89 
  

  

  3*310 
  

  

  3 
  

  

  395 
  

  

  

  " 
  29 
  

  

  16 
  

  

  4-30 
  

  

  2-67 
  

  

  0-89 
  

  

  3*238 
  

  

  3 
  

  

  331 
  

  

  

  Aug. 
  8 
  

  

  18 
  

  

  4-48 
  

  

  2'63 
  

  

  0-86 
  

  

  3-279 
  

  

  3 
  

  

  352 
  

  

  

  " 
  21 
  

  

  18 
  

  

  4-33 
  

  

  3-67 
  

  

  0-95 
  

  

  3-104 
  

  

  3 
  

  

  157 
  

  

  

  " 
  23 
  

  

  16 
  

  

  3-81 
  

  

  3'13 
  

  

  0*93 
  

  

  3-472 
  

  

  3 
  

  

  529 
  

  

  

  " 
  25 
  

  

  16 
  

  

  4*34 
  

  

  3-21 
  

  

  0-95 
  

  

  3-329 
  

  

  3 
  

  

  381 
  

  

  

  Sept. 
  18 
  

  

  12 
  

  

  3*43 
  

  

  3-08 
  

  

  0-97 
  

  

  3-204 
  

  

  3 
  

  

  214 
  

  

  

  Oct. 
  4 
  

  

  13 
  

  

  2*47 
  

  

  3-86 
  

  

  1-08 
  

  

  3-069 
  

  

  3 
  

  

  051 
  

  

  

  6 
  

  

  12 
  

  

  2-44 
  

  

  3-09 
  

  

  1-06 
  

  

  3-887 
  

  

  3 
  

  

  859 
  

  

  

  " 
  9 
  

  

  14 
  

  

  2-57 
  

  

  3*10 
  

  

  1-08 
  

  

  3-151 
  

  

  3 
  

  

  123 
  

  

  

  " 
  11 
  

  

  14 
  

  

  2-97 
  

  

  3'29 
  

  

  1-09 
  

  

  3-148 
  

  

  3 
  

  

  116 
  

  

  

  " 
  13 
  

  

  12 
  

  

  2-18 
  

  

  3*32 
  

  

  1-14 
  

  

  3-070 
  

  

  3 
  

  

  036 
  

  

  

  " 
  16 
  

  

  12 
  

  

  2-91 
  

  

  3-62 
  

  

  1-15 
  

  

  3-410 
  

  

  3 
  

  

  366 
  

  

  

  " 
  18 
  

  

  11 
  

  

  3-76 
  

  

  3*90 
  

  

  1-13 
  

  

  3-339 
  

  

  3 
  

  

  293 
  

  

  

  " 
  20 
  

  

  10 
  

  

  1-59 
  

  

  3-50 
  

  

  1-26 
  

  

  3-245 
  

  

  3 
  

  

  196 
  

  

  

  " 
  23 
  

  

  18 
  

  

  1-92 
  

  

  4-47 
  

  

  1-18 
  

  

  3-287 
  

  

  3-232 
  

  

  

  Mean 
  

  

  Aq.= 
  

  

  3-340 
  

  

  

  Mean 
  

  

  A= 
  

  

  3-246 
  

  

  mer 
  and 
  winter 
  readings, 
  and 
  that 
  the 
  remaining 
  discrepancies 
  

   arise 
  from 
  the 
  inadequacy 
  of 
  the 
  surface 
  vapor 
  pressure 
  as 
  an 
  

   indicator 
  of 
  total 
  moisture. 
  The 
  chart 
  is 
  also 
  imperfect 
  

   because 
  the 
  absorption 
  of 
  radiation 
  by 
  water 
  vapor 
  varies 
  with 
  

   the 
  relative 
  humidity 
  as 
  well 
  as 
  with 
  the 
  vapor 
  pressure, 
  while 
  

   only 
  the 
  latter 
  is 
  considered 
  here. 
  To 
  illustrate 
  the 
  great 
  dis- 
  

   advantage 
  under 
  which 
  we 
  labor 
  in 
  estimating 
  the 
  effect 
  of 
  

   aqueous 
  vapor 
  upon 
  radiation, 
  it 
  is 
  only 
  necessary 
  to 
  point 
  out 
  

   that 
  a 
  layer 
  of 
  air 
  approaching 
  saturation, 
  but 
  not 
  yet 
  visibly 
  

   cloudy, 
  may 
  occur 
  at 
  various 
  altitudes, 
  and 
  that 
  sometimes 
  

   several 
  such 
  layers 
  are 
  found 
  in 
  succession 
  in 
  balloon 
  ascents. 
  

   But 
  the 
  absorption 
  by 
  water 
  vapor 
  is 
  strongly 
  enhanced 
  near 
  

   the 
  condensation 
  point, 
  and 
  the 
  unknown 
  possibilities 
  of 
  the 
  

  

  