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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1927 
  

  

  has 
  found 
  that 
  the 
  reception 
  of 
  long-range 
  radio 
  signals 
  also 
  marches 
  

   hand 
  in 
  hand 
  with 
  the 
  intensity 
  of 
  solar 
  radiation. 
  

  

  The 
  weather, 
  too, 
  so 
  important 
  to 
  human 
  concerns, 
  seems 
  to 
  be 
  

   affected 
  by 
  solar 
  changes. 
  The 
  importance 
  of 
  this 
  effect 
  is 
  still 
  in 
  

   controversy, 
  so 
  that 
  I 
  shall 
  not 
  stress 
  it, 
  but 
  merely 
  remark 
  that 
  time 
  

   will 
  tell. 
  However, 
  I 
  must 
  point 
  out 
  that 
  the 
  solar 
  variation, 
  though 
  

   obviously 
  associated 
  with 
  the 
  11-year 
  sun-spot 
  cycle, 
  has 
  hitherto 
  

   seemed 
  irregular, 
  and 
  therefore 
  unpredictable. 
  But 
  now 
  there 
  seem 
  

   to 
  appear 
  definite 
  periodicities 
  of 
  25%, 
  15, 
  and 
  11 
  months, 
  and 
  cer- 
  

   tain 
  harmonics 
  of 
  these 
  periods, 
  which, 
  together 
  with 
  the 
  11-year 
  

   period, 
  seem 
  to 
  make 
  up 
  the 
  whole 
  long-interval 
  solar 
  variation. 
  If 
  

   tliese 
  definite 
  periodicities 
  should 
  persist, 
  we 
  shall 
  be 
  in 
  position 
  to 
  

   forecast 
  for 
  years 
  in 
  advance 
  the 
  principal 
  solar 
  variation 
  and 
  every- 
  

   thing 
  which 
  may 
  be 
  found 
  to 
  depend 
  upon 
  it. 
  

  

  I 
  should 
  give 
  but 
  a 
  feeble 
  impression 
  of 
  the 
  importance 
  of 
  sunlight 
  

   to 
  life 
  if 
  I 
  should 
  stop 
  at 
  this 
  point. 
  All 
  plants 
  grow 
  by 
  absorbing 
  

   solar 
  energy 
  and 
  using 
  it 
  to 
  promote 
  chemical 
  reactions 
  in 
  a 
  way 
  still 
  

   inimitable 
  by 
  cliemists. 
  Ultra-violet 
  rays, 
  too, 
  produce 
  certain 
  

   changes 
  of 
  chemical 
  structure 
  in 
  fats 
  and 
  oils 
  which 
  are 
  the 
  source 
  

   of 
  those 
  traces 
  of 
  hormones 
  so 
  extraordinarily 
  important, 
  all 
  out 
  of 
  

   proportion 
  to 
  their 
  infinitesimal 
  occurrence, 
  in 
  the 
  growth 
  and 
  health 
  

   of 
  animals. 
  The 
  more 
  searching 
  study 
  of 
  the 
  solar 
  spectrum 
  in 
  its 
  

   relations. 
  to 
  these 
  extraordinary 
  chemical 
  reactions 
  is 
  a 
  most 
  fasci- 
  

   nating 
  field. 
  

  

  On 
  the 
  grosser 
  side 
  the 
  application 
  of 
  solar 
  energy 
  to 
  power 
  pro- 
  

   duction 
  also 
  offers 
  an 
  attractive 
  research 
  field. 
  Some 
  are 
  disposed 
  

   to 
  think 
  this 
  chimerical. 
  There 
  are, 
  however, 
  certain 
  lines 
  of 
  im- 
  

   provement 
  over 
  former 
  attempts 
  at 
  the 
  utilization 
  of 
  solar 
  rays 
  

   directly 
  for 
  power 
  which, 
  I 
  am 
  inclined 
  to 
  think, 
  will 
  solve 
  tlw 
  

   problem 
  commercially. 
  

  

  Thus 
  far 
  we 
  have 
  mentioned 
  only 
  points 
  of 
  contact 
  between 
  astro- 
  

   nomical 
  research 
  and 
  physical 
  life. 
  Yet 
  this 
  aspect, 
  interesting 
  as 
  

   it 
  is, 
  should 
  yield 
  place 
  to 
  appreciation 
  of 
  the 
  value 
  of 
  astronomy 
  

   to 
  broaden 
  the 
  mental 
  outlook, 
  to 
  vanquish 
  fear, 
  and 
  to 
  allay 
  super- 
  

   stition. 
  While 
  yet 
  the 
  vast 
  numbers 
  and 
  masses 
  of 
  the 
  stars 
  were 
  

   unknown, 
  their 
  nature 
  unrecognized, 
  the 
  existence 
  of 
  other 
  galaxies 
  

   undreamed 
  of, 
  men 
  very 
  naturally 
  regarded 
  the 
  earth 
  as 
  the 
  central 
  

   object 
  and 
  themselves 
  the 
  beings 
  for 
  whom 
  all 
  things 
  were 
  created. 
  

   Now 
  the 
  universe 
  has 
  attained 
  such 
  grandeur 
  that 
  earth 
  sinks 
  to 
  

   the 
  dimensions 
  of 
  a 
  speck, 
  and 
  we 
  can 
  not 
  but 
  accept 
  an 
  attitude 
  of 
  

   wholesome 
  humility. 
  At 
  the 
  same 
  time, 
  the 
  consciousness 
  of 
  having 
  

   achieved 
  already 
  so 
  great 
  a 
  command 
  of 
  the 
  forces 
  of 
  nature, 
  and 
  so 
  

   considerable 
  a 
  Imowledge 
  of 
  her 
  mysteries, 
  and 
  the 
  assurance 
  that 
  

   we 
  can 
  soon 
  connnand 
  and 
  know 
  far 
  more, 
  tempers 
  humility 
  with 
  

   elation. 
  

  

  