﻿10 
  

  

  ON 
  THE 
  DIURNAL 
  VARIATION 
  

  

  the 
  platform, 
  and 
  half 
  hourly 
  observations 
  were 
  resorted 
  to 
  about 
  some 
  

   of 
  the 
  times 
  remarked 
  by 
  former 
  observations 
  as 
  containing 
  maxima 
  or 
  

   minima 
  of 
  variation. 
  

  

  The 
  curves 
  given 
  by 
  these 
  observations 
  are 
  traced 
  on 
  No. 
  4, 
  Plate 
  I.* 
  

   The 
  free 
  radiation 
  of 
  heat 
  during 
  the 
  night 
  from 
  the 
  earth, 
  caused 
  a 
  

   great 
  depression 
  in 
  the 
  temperature 
  of 
  the 
  air 
  near 
  to 
  it, 
  the 
  sunrise 
  

   minimum 
  of 
  the 
  thermometer 
  being 
  as 
  low 
  as 
  44°, 
  the 
  maximum 
  of 
  

   the 
  day 
  having 
  been 
  69|°. 
  

  

  TABLE 
  V. 
  

  

  Hour. 
  

  

  N. 
  Pole 
  W. 
  

  

  Temp. 
  Remarks. 
  

  

  Hour. 
  

  

  N. 
  Pole 
  W. 
  

  

  Temp. 
  

  

  Remarks. 
  

  

  

  Deg. 
  Min. 
  

  

  Deg. 
  

  

  

  

  Deg. 
  Min. 
  

  

  Deg. 
  

  

  

  12 
  M. 
  

  

  3 
  18.7 
  

  

  76 
  

  

  Sept. 
  2. 
  Clear. 
  

  

  

  

  

  Sept. 
  3. 
  

  

  12| 
  P.M. 
  

  

  3 
  19.9 
  

  

  77£ 
  

  

  Clear. 
  

  

  

  

  

  

  1 
  P.M. 
  

  

  3 
  25.4 
  

  

  80§ 
  

  

  Clear. 
  

  

  

  

  

  

  n 
  p.m. 
  

  

  3 
  25.4 
  

  

  80 
  

  

  Clear. 
  

  

  

  

  

  

  2 
  P.M. 
  

  

  3 
  25.4 
  

  

  81 
  

  

  Clear. 
  

  

  

  

  

  

  2h 
  P.M. 
  

  

  3 
  26.9 
  

  

  79i 
  

  

  Clear. 
  

  

  

  

  

  

  3 
  P.M. 
  

  

  3 
  26.9 
  

  

  79j 
  

  

  Clear. 
  

  

  

  

  

  

  3| 
  P.M. 
  

  

  3 
  26.9 
  

  

  79| 
  

  

  Clear. 
  

  

  

  

  

  

  4 
  P.M. 
  

  

  3 
  26.9 
  

  

  79J 
  

  

  Clear. 
  

  

  

  

  

  

  5 
  P.M. 
  

  

  3 
  25.4 
  

  

  76 
  

  

  Clear. 
  

  

  

  

  

  

  6 
  P.M. 
  

  

  3 
  23.0 
  

  

  70 
  

  

  Clear. 
  

   " 
  Sun 
  sets. 
  Sky 
  

  

  

  

  

  

  ei 
  P.M. 
  

  

  3 
  23.0 
  

  

  

  generally 
  clear. 
  

   ' 
  Cirrus 
  and 
  light 
  

   . 
  cumulus. 
  

  

  

  

  

  

  7 
  P.M. 
  

  

  3 
  25.4 
  

  

  63 
  

  

  Clear. 
  

   (" 
  Cloudy. 
  Moon 
  

   wading 
  through 
  

   j 
  dark 
  cirro-cu- 
  

   l_ 
  mulus. 
  

  

  

  

  

  f 
  Therm, 
  near 
  

  

  8 
  P.M 
  

  

  3 
  29.3 
  

  

  60 
  

  

  8 
  A.M. 
  

  

  3 
  26.2 
  

  

  64 
  

  

  house. 
  Cloudy. 
  

   1 
  Dark 
  cumulo- 
  

  

  

  

  

  

  

  

  |_ 
  stratus. 
  

  

  9 
  P.M. 
  

  

  3 
  29.3 
  

  

  58 
  

  

  Cloudy. 
  

  

  9 
  A.M. 
  

  

  3 
  21.9 
  

  

  64 
  

  

  f 
  Cloudy. 
  Wind 
  

   1 
  N. 
  E. 
  

  

  10 
  P.M. 
  

  

  3 
  27.7 
  

  

  58 
  

  

  C 
  Clouds 
  more 
  

   I 
  dense. 
  

  

  10 
  A.M. 
  

  

  3 
  22.6 
  

  

  

  Cloudy. 
  

  

  11 
  P.M. 
  

  

  3 
  26.2 
  

  

  58 
  

  

  fMoon 
  dips 
  be- 
  

   l 
  hind 
  hill. 
  

  

  11 
  AM. 
  

  

  3 
  23.0 
  

  

  65| 
  

  

  Cloudy. 
  

  

  

  

  

  

  12 
  M. 
  

  

  3 
  22.6 
  

  

  65h 
  

  

  Raining. 
  

  

  