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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  helping 
  knowledge 
  needed 
  from 
  meteorology 
  has 
  not 
  yet 
  been 
  gar- 
  

   nered 
  by 
  that 
  science. 
  For 
  example, 
  the 
  conditions 
  for 
  tree 
  growth 
  

   are 
  markedly 
  different 
  on 
  the 
  east 
  and 
  west 
  sides 
  of 
  a 
  mountain 
  

   or 
  on 
  the 
  north 
  and 
  south 
  slopes. 
  The 
  first 
  involves 
  difference 
  of 
  

   exposure 
  to 
  rain-bearing 
  winds, 
  and 
  the 
  second 
  means 
  entirely 
  dif- 
  

   ferent 
  exposure 
  to 
  sun 
  and 
  shade. 
  The 
  latter 
  contrast 
  has 
  been 
  

   studied 
  on 
  the 
  Catalina 
  Mountains 
  by 
  Forrest 
  Shreve. 
  Again, 
  the 
  

   Weather 
  Bureau 
  stations 
  are 
  largely 
  located 
  in 
  cities 
  and, 
  therefore, 
  

   we 
  can 
  not 
  get 
  data 
  from 
  proper 
  places 
  in 
  the 
  Sierra 
  Nevada 
  Moun- 
  

   tains 
  of 
  California, 
  where 
  the 
  Giant 
  Sequoia 
  lives. 
  Considering 
  

   that 
  this 
  Big 
  Tree 
  gives 
  us 
  the 
  longest 
  uninterrupted 
  series 
  of 
  annual 
  

   climatic 
  effects 
  of 
  known 
  date, 
  which 
  we 
  have 
  so 
  far 
  obtained 
  from 
  

   any 
  source, 
  it 
  must 
  be 
  greatly 
  regretted 
  that 
  we 
  have 
  no 
  good 
  modern 
  

   records 
  by 
  which 
  to 
  interpret 
  the 
  writing 
  in 
  these 
  wonderful 
  trees, 
  

   and, 
  so 
  far 
  as 
  I 
  am 
  aware, 
  no 
  attempt 
  is 
  yet 
  being 
  made 
  to 
  get 
  com- 
  

   plete 
  records 
  for 
  the 
  future. 
  

  

  In 
  reviewing 
  the 
  environment, 
  one 
  must 
  go 
  another 
  step. 
  One 
  

   of 
  the 
  early 
  results 
  of 
  this 
  study 
  was 
  the 
  fact 
  that 
  in 
  many 
  different 
  

   wet 
  climates 
  the 
  growth 
  of 
  trees 
  follows 
  closely 
  and 
  sometimes 
  

   fundamentally 
  certain 
  solar 
  variations. 
  That 
  means 
  astronomical 
  

   relationship. 
  It 
  becomes 
  then 
  an 
  interesting 
  fact 
  that 
  the 
  first 
  two 
  

   serious 
  attempts 
  to 
  trace 
  climatic 
  effects 
  in 
  trees 
  were 
  made 
  by 
  

   astronomers. 
  I 
  do 
  not 
  know 
  exactly 
  what 
  inspired 
  Professor 
  

   Kapteyn, 
  the 
  noted 
  astronomer 
  of 
  Groningen, 
  Holland, 
  to 
  study 
  

   the 
  relation 
  of 
  oak 
  rings 
  to 
  rainfall 
  in 
  the 
  Ehineland, 
  which 
  he 
  did 
  

   in 
  1880 
  and 
  1881 
  (without 
  publishing), 
  but 
  for 
  my 
  own 
  case 
  I 
  can 
  

   be 
  more 
  explicit. 
  It 
  was 
  a 
  thought 
  of 
  the 
  possibility 
  of 
  determin- 
  

   ing 
  variations 
  in 
  solar 
  activity 
  by 
  the 
  effect 
  of 
  terrestrial 
  weather 
  

   on 
  tree 
  growth. 
  This, 
  one 
  notes, 
  assumed 
  an 
  effect 
  of 
  the 
  sun 
  on 
  

   our 
  weather 
  and 
  recognized 
  trees 
  as 
  'one 
  of 
  nature's 
  great 
  recording 
  

   mechanisms. 
  

  

  But 
  the 
  possible 
  relationship 
  of 
  solar 
  activity 
  to 
  weather 
  is 
  a 
  

   part 
  of 
  a 
  rather 
  specialized 
  department 
  of 
  astronomical 
  science, 
  

   called 
  astrophysics. 
  And 
  there 
  is 
  a 
  great 
  deal 
  of 
  help 
  which 
  one 
  

   wants 
  from 
  that 
  science, 
  but 
  which 
  one 
  can 
  not 
  yet 
  obtain; 
  for 
  

   example, 
  the 
  hourly 
  variations 
  in 
  the 
  solar 
  constant. 
  I 
  would 
  like 
  

   to 
  know 
  whether 
  the 
  relative 
  rate 
  of 
  rotation 
  and 
  the 
  relative 
  tem- 
  

   peratures 
  of 
  different 
  solar 
  latitudes 
  vary 
  in 
  terms 
  of 
  the 
  11-year 
  

   sun-spot 
  period. 
  These 
  questions 
  have 
  to 
  do 
  with 
  some 
  of 
  the 
  

   theories 
  proposed 
  in 
  attempting 
  to 
  explain 
  the 
  sun-spot 
  periodicity. 
  

   We 
  do 
  not 
  know 
  the 
  cause 
  of 
  the 
  11-year 
  sun-spot 
  period. 
  Here 
  

   then 
  is 
  work 
  for 
  the 
  astronomers. 
  

  

  Yet 
  another 
  important 
  contact 
  has 
  this 
  study 
  developed. 
  The 
  

   rings 
  in 
  the 
  beams 
  of 
  ancient 
  ruins 
  tell 
  a 
  story 
  of 
  the 
  time 
  of 
  build- 
  

  

  