﻿Rain, 
  Wind, 
  and 
  Cyclones. 
  235 
  

  

  the 
  varying 
  sunrise 
  and 
  sunset 
  effects, 
  are 
  otherwise 
  difficult 
  

   to 
  explain. 
  

  

  The 
  energy 
  of 
  impact 
  of 
  the 
  cosmic 
  dust 
  need 
  not 
  be 
  as 
  

   great 
  as 
  the 
  energy 
  of 
  the 
  cyclone 
  produced 
  ; 
  for 
  the 
  winds 
  

   and 
  isobars 
  of 
  a 
  cyclone 
  are 
  to 
  a 
  large 
  extent 
  a 
  modified 
  

   arrangement 
  of 
  existing 
  isobars 
  and 
  winds. 
  

  

  Cyclones 
  according 
  to 
  this 
  theory 
  must 
  travel 
  with 
  the 
  

   winds 
  of 
  the 
  upper 
  atmosphere. 
  That 
  cyclones 
  originate 
  at 
  

   high 
  levels 
  and 
  extend 
  downwards 
  would 
  seem 
  to 
  be 
  implied 
  

   by 
  the 
  following 
  remark 
  of 
  Shaw 
  and 
  Lernpfert*: 
  u 
  This 
  

   disturbance 
  moved 
  slowly 
  in 
  a 
  north-westerly 
  direction 
  

   and 
  finally 
  passed 
  away 
  to 
  the 
  North 
  Sea. 
  In 
  the 
  early 
  

   stages 
  small 
  ' 
  secondary 
  ' 
  minima 
  of 
  pressure 
  developed 
  near 
  

   the 
  primary 
  minimum, 
  and 
  the 
  process 
  of 
  travel 
  appears 
  to 
  

   consist 
  in 
  the 
  formation 
  of 
  a 
  ' 
  secondary 
  ' 
  in 
  front 
  of 
  the 
  storm, 
  

   and 
  the 
  filling 
  up 
  of 
  the 
  original 
  minimum." 
  

  

  The 
  local 
  heating 
  of 
  the 
  upper 
  portion 
  of 
  the 
  stratosphere 
  

   which 
  is 
  considered 
  to 
  result 
  in 
  the 
  formation 
  of 
  travelling 
  

   cyclones, 
  is 
  regarded 
  as 
  being 
  produced 
  rapidly 
  and 
  as 
  dying 
  

   away 
  slowly. 
  In 
  the 
  case 
  of 
  the 
  polar 
  fixed 
  cyclones 
  the 
  

   heating 
  of 
  the 
  upper 
  atmosphere 
  must 
  be 
  a 
  continuous 
  

   process 
  or 
  nearly 
  so 
  ; 
  the 
  heat 
  is 
  always 
  passing 
  downwards 
  

   as 
  rapidly 
  as 
  the 
  air 
  moving 
  into 
  the 
  lower 
  portion 
  of 
  the 
  

   cyclone 
  raises 
  the 
  upper 
  surface 
  of 
  the 
  stratosphere, 
  and 
  the 
  

   vertical 
  distribution 
  of 
  temperature 
  in 
  the 
  atmosphere 
  remains 
  

   nearly 
  constant. 
  

  

  One 
  would 
  expect 
  the 
  weather 
  conditions 
  to 
  be 
  much 
  less 
  

   variable 
  if 
  they 
  depended 
  wholly 
  upon 
  the 
  physical 
  features 
  

   of 
  the 
  earth's 
  surface 
  and 
  the 
  radiations 
  received 
  from 
  the 
  sun. 
  

   Indeed 
  the 
  Trade 
  Winds, 
  and 
  even 
  the 
  general 
  circulation 
  

   of 
  the 
  atmosphere, 
  are 
  fairly 
  regular. 
  It 
  is 
  to 
  wandering- 
  

   cyclones 
  that 
  our 
  short-period 
  weather 
  variability 
  is 
  due, 
  and 
  

   the 
  want 
  of 
  regularity 
  in 
  the 
  manner 
  of 
  their 
  occurrence 
  

   would 
  be 
  only 
  what 
  might 
  be 
  expected 
  if 
  they 
  were 
  caused 
  by 
  

   irregular 
  streams 
  of 
  cosmic 
  matter. 
  Indeed, 
  our 
  atmosphere 
  

   probably 
  protects 
  us 
  from 
  a 
  bombardment 
  from 
  space, 
  not 
  only 
  

   of 
  matter 
  but 
  of 
  many 
  undesirable 
  radiations. 
  However, 
  

   the 
  energy 
  received 
  from 
  the 
  sun 
  is 
  probably 
  somewhat 
  

   irregular 
  in 
  its 
  amount 
  owing 
  to 
  the 
  formation 
  and 
  dis- 
  

   appearance 
  of 
  spots 
  on 
  the 
  sun, 
  and 
  some 
  relationship 
  

   undoubtedly 
  exists 
  between 
  weather 
  condition 
  variations 
  

   and 
  sun-spot 
  periods. 
  

  

  