﻿FOGS 
  AND 
  CLOUDS 
  — 
  HUMPHREYS. 
  217 
  

  

  VARIATION 
  OF 
  CLOUDINESS 
  WITH 
  LATITUDE. 
  

  

  As 
  is 
  well 
  known, 
  the 
  amount 
  of 
  cloudiness 
  varies 
  greatly 
  in 
  dif- 
  

   ferent 
  parts 
  of 
  the 
  world. 
  In 
  some 
  places 
  it 
  would 
  be 
  perfectly 
  safe, 
  

   following 
  the 
  example 
  of 
  the 
  Yuma 
  Hotel, 
  to 
  advertise 
  free 
  meals 
  

   for 
  every 
  day 
  the 
  sun 
  does 
  not 
  shine, 
  and 
  equally 
  safe 
  in 
  others 
  to 
  

   make 
  a 
  similar 
  offer 
  for 
  every 
  whole 
  day 
  that 
  it 
  does. 
  Apart 
  from 
  

   such 
  obvious 
  causes 
  of 
  cloud 
  variation 
  as 
  direction 
  of 
  the 
  wind, 
  

   particularly 
  onshore 
  and 
  offshore, 
  elevation, 
  temperature, 
  etc., 
  there 
  

   is 
  also 
  a 
  well-marked 
  latitude 
  effect. 
  Thus, 
  in 
  the 
  equatorial 
  regions, 
  

   where 
  convection 
  is 
  most 
  active, 
  nearly 
  60 
  per 
  cent, 
  on 
  the 
  average, 
  

   of 
  the 
  sky 
  is 
  clouded; 
  around 
  latitude 
  30°, 
  both 
  north 
  and 
  south, 
  

   or 
  along 
  the 
  great 
  belts 
  of 
  high 
  pressure 
  and 
  over 
  the 
  principal 
  arid 
  

   regions 
  the 
  average 
  cloudiness 
  falls 
  to 
  the 
  minimum 
  value 
  of 
  40 
  

   to 
  45 
  per 
  cent, 
  while 
  in 
  the 
  neighborhood 
  of 
  the 
  polar 
  regions 
  it 
  

   becomes 
  60 
  to 
  75 
  per 
  cent. 
  All 
  these 
  are 
  only 
  average 
  values 
  for 
  the 
  

   respective 
  latitudes. 
  The 
  cloudiness 
  of 
  individual 
  places 
  covers 
  a 
  

   much 
  wider 
  variation. 
  

  

  CLOUD 
  SPLENDORS. 
  

  

  Crepuscular 
  rays. 
  — 
  Everyone 
  is 
  familiar 
  with 
  the 
  beautiful 
  phe- 
  

   nomenon 
  of 
  the 
  "sun 
  drawing 
  water" 
  (pi. 
  25, 
  fig. 
  1) 
  — 
  sunbeams, 
  

   that, 
  finding 
  their 
  way 
  through 
  rifts 
  in 
  the 
  clouds, 
  are 
  rendered 
  

   luminous 
  by 
  the 
  dust 
  in 
  their 
  paths. 
  Many 
  people 
  seem 
  to 
  consider 
  

   this 
  splendor 
  an 
  excellent 
  weather 
  sign, 
  some 
  insisting 
  that 
  it 
  fore- 
  

   tells 
  rain, 
  while 
  others 
  as 
  strongly 
  claim 
  it 
  indicates 
  continued 
  fair. 
  

   As 
  a 
  matter 
  of 
  fact, 
  it 
  has 
  no 
  significance 
  either 
  way, 
  hence 
  its 
  

   excellence 
  as 
  a 
  bone 
  of 
  contention. 
  

  

  When 
  there 
  are 
  a 
  number 
  of 
  such 
  rifts 
  the 
  beams 
  of 
  light 
  seem 
  

   to 
  radiate 
  from 
  the 
  sun 
  like 
  spokes 
  from 
  the 
  hub 
  of 
  a 
  great 
  wheel, 
  

   or 
  like 
  ribs 
  from 
  the 
  pivot 
  of 
  a 
  giant 
  fan. 
  However, 
  they 
  are 
  prac- 
  

   tically 
  parallel, 
  for 
  the 
  sun, 
  from 
  which 
  they 
  all 
  come, 
  is 
  93,000,000 
  

   miles 
  away. 
  The 
  seeming 
  divergence 
  is 
  only 
  a 
  perspective 
  illusion, 
  

   the 
  same 
  as 
  that 
  which 
  makes 
  any 
  long, 
  straight, 
  parallel 
  lines 
  — 
  such, 
  

   for 
  instance, 
  as 
  the 
  rails 
  on 
  a 
  straight, 
  level 
  track 
  of 
  railway 
  — 
  appear 
  

   to 
  come 
  closer 
  and 
  closer 
  together 
  with 
  increase 
  of 
  distance. 
  

  

  Lightning. 
  — 
  Few 
  things 
  in 
  all 
  nature 
  so 
  widely 
  range 
  our 
  sensi- 
  

   bilities, 
  from 
  thrills 
  of 
  joy 
  over 
  the 
  exquisitely 
  beautiful 
  to 
  abject 
  

   terror 
  in 
  the 
  face 
  of 
  imminent 
  death, 
  as 
  does 
  the 
  lightning's 
  flash 
  

   from 
  the 
  heart 
  of 
  the 
  thundercloud. 
  

  

  The 
  story 
  of 
  this 
  wonder 
  meteor 
  — 
  how 
  Franklin 
  showed 
  it 
  to 
  be 
  

   a 
  form 
  of 
  electric 
  discharge; 
  how, 
  as 
  explained 
  by 
  Simpson, 
  charge 
  

   after 
  charge 
  is 
  obtained 
  within 
  the 
  cloud; 
  what 
  curious 
  freaks 
  it 
  

   plays 
  and 
  marvelous 
  things 
  it 
  does 
  — 
  is 
  delightful 
  in 
  every 
  detail 
  

  

  