﻿234 
  Mr. 
  R. 
  M. 
  Deeley 
  on 
  

  

  The 
  general 
  surface 
  winds 
  of 
  the 
  globe, 
  like 
  those 
  o£ 
  

   cyclones, 
  generally 
  cross 
  the 
  isobars 
  at 
  angles 
  more 
  or 
  less 
  

   acute. 
  It 
  is 
  probable, 
  however, 
  that 
  all 
  the 
  winds 
  of 
  the 
  

   world 
  above 
  1000 
  metres, 
  or 
  even 
  lower, 
  follow 
  the 
  isobars 
  

   very 
  closely, 
  and 
  that 
  the 
  energy 
  of 
  cyclones 
  both 
  large 
  and 
  

   small 
  is 
  dissipated 
  mainly 
  by 
  friction 
  at 
  or 
  near 
  the 
  earth's 
  

   surface. 
  Although 
  the 
  energy 
  represented 
  by 
  such 
  move- 
  

   ments 
  is 
  very 
  large, 
  it 
  would 
  be 
  easy 
  to 
  overrate 
  the 
  strength 
  

   of 
  the 
  forces 
  required 
  to 
  keep 
  them 
  going 
  or 
  to 
  start 
  them. 
  

   We 
  must 
  regard 
  the 
  circulation 
  of 
  the 
  atmosphere 
  much 
  as 
  

   we 
  do 
  the 
  movement 
  of 
  the 
  planets, 
  moons, 
  comets, 
  &c. 
  of 
  the 
  

   solar 
  system 
  ; 
  but 
  the 
  retarding 
  frictional 
  forces 
  are 
  greater 
  

   in 
  the 
  case 
  of 
  the 
  atmosphere 
  than 
  they 
  are 
  in 
  the 
  case 
  of 
  the 
  

   solar 
  system. 
  

  

  I 
  have 
  ventured 
  to 
  show 
  what 
  I 
  regard 
  as 
  the 
  general 
  

   directions 
  of 
  the 
  slow 
  movement 
  of 
  the 
  winds 
  across 
  the 
  

   isobars 
  in 
  figs. 
  6 
  & 
  7. 
  

  

  In 
  the 
  case 
  of 
  fig. 
  6, 
  the 
  arrows 
  show 
  the 
  assumed 
  very 
  

   slow 
  movement 
  to 
  or 
  from 
  the 
  centre 
  of 
  the 
  cyclone 
  during 
  

   its 
  growth. 
  The 
  velocity 
  of 
  the 
  wind 
  along 
  the 
  isobars 
  may 
  

   be 
  high. 
  In 
  fig. 
  7 
  the 
  arrows 
  also 
  show 
  the 
  assumed 
  steady 
  

   movement 
  to 
  and 
  from 
  the 
  centre 
  of 
  the 
  cyclone. 
  The 
  velocity 
  

   along 
  the 
  isobars 
  may 
  also 
  be 
  great. 
  

  

  The 
  temperature 
  distribution 
  in 
  the 
  atmosphere 
  appears 
  

   to 
  be 
  the 
  result 
  of 
  heating 
  mainly 
  in 
  two 
  ways. 
  At 
  the 
  

   upper 
  surface 
  there 
  may 
  be 
  arrested 
  many 
  kinds 
  of 
  radiation 
  

   (undulatory 
  and 
  material) 
  and 
  also 
  cosmic 
  matter 
  moving 
  at 
  

   high 
  velocities. 
  It 
  is 
  thus 
  heated 
  at 
  its 
  upper 
  surface, 
  and 
  

   this 
  heat 
  passes 
  downwards 
  and 
  gives 
  us 
  the 
  conditions 
  of 
  

   temperature 
  found 
  in 
  the 
  stratosphere. 
  Light 
  and 
  heat 
  rays 
  

   pass 
  through 
  the 
  atmosphere 
  until 
  they 
  reach 
  clouds 
  in 
  the 
  

   lower 
  atmosphere 
  or 
  the 
  earth's 
  surface. 
  From 
  here 
  the 
  heat 
  

   rises 
  and 
  the 
  temperature 
  conditions 
  of 
  convective 
  equilibrium 
  

   are 
  established 
  in 
  the 
  lower 
  atmosphere. 
  

  

  I 
  have 
  suggested 
  * 
  that 
  the 
  great 
  heating 
  of 
  the 
  upper 
  

   surface 
  of 
  the 
  atmosphere 
  over 
  the 
  poles 
  is 
  primarily 
  due 
  to 
  

   the 
  electrons 
  shot 
  out 
  by 
  the 
  sun, 
  which, 
  being 
  caught 
  by 
  the 
  

   earth's 
  magnetic 
  field, 
  are 
  directed 
  towards 
  the 
  poles, 
  the 
  air 
  

   in 
  the 
  neighbourhood 
  of 
  which 
  they 
  heat 
  and 
  probably 
  ionize. 
  

   But 
  we 
  have 
  to. 
  account 
  for 
  the 
  local 
  heating 
  of 
  the 
  upper 
  

   surface 
  of 
  the 
  atmosphere 
  required 
  to 
  produce 
  cyclones. 
  It 
  

   maybe 
  due 
  to 
  pencils 
  of 
  high-velocity 
  cosmic 
  matter; 
  for 
  the 
  

   optical 
  properties 
  of 
  the 
  upper 
  atmosphere, 
  as 
  indicated 
  by 
  

  

  * 
  Phil. 
  Trans, 
  vol. 
  xxxi., 
  April 
  1916. 
  

  

  