﻿REPORT 
  OF 
  THE 
  SECRETARY 
  101 
  

  

  constant 
  of 
  radiation, 
  has 
  continued 
  regular 
  observations 
  and 
  has 
  

   sent 
  to 
  Washington 
  a 
  large 
  collection 
  of 
  records. 
  These 
  will 
  be 
  

   statistically 
  and 
  critically 
  studied 
  and 
  prepared 
  for 
  publication. 
  

  

  As 
  the 
  observers, 
  Messrs. 
  Hoover 
  and 
  Greeley, 
  have 
  been 
  three 
  

   years 
  in 
  this 
  African 
  field, 
  arrangements 
  have 
  been 
  made 
  for 
  Messrs. 
  

   Sordahl 
  and 
  Froiland 
  to 
  relieve 
  them 
  in 
  August, 
  1929. 
  

  

  PERSONNEL 
  

  

  At 
  the 
  stations 
  Mr. 
  A. 
  F. 
  Moore 
  has 
  continued 
  in 
  charge 
  at 
  Table 
  

   Mountain 
  and 
  Mr. 
  H. 
  H. 
  Zodtner 
  at 
  Montezuma. 
  Mr. 
  Moore 
  was 
  

   assisted 
  mainly 
  by 
  Mr. 
  L. 
  O. 
  Sordahl, 
  and 
  after 
  his 
  departure, 
  in 
  

   June, 
  1929, 
  by 
  Dr. 
  W. 
  Weniger. 
  Mr. 
  Zodtner 
  was 
  assisted 
  until 
  

   April 
  1 
  by 
  Mr. 
  M. 
  K. 
  Baughman 
  and 
  after 
  his 
  resignation 
  by 
  Mr. 
  

   C. 
  P. 
  Butler. 
  

  

  At 
  Washington 
  the 
  force 
  has 
  remained 
  unchanged, 
  with 
  three 
  

   exceptions. 
  Mrs. 
  A. 
  M. 
  Bond 
  resigned 
  as 
  coniputor 
  on 
  February 
  5, 
  

   1929. 
  She 
  was 
  succeeded 
  on 
  February 
  18 
  by 
  Miss 
  M. 
  Denoyer. 
  Mr. 
  

   H. 
  B. 
  Freeman, 
  formerly 
  in 
  charge 
  of 
  Montezuma 
  station, 
  assisted 
  at 
  

   Mount 
  Wilson 
  and 
  at 
  Washington 
  until 
  May 
  1, 
  1929, 
  when 
  he 
  ob- 
  

   tained 
  a 
  transfer 
  to 
  the 
  laboratories 
  of 
  the 
  National 
  Advisory 
  

   Committee 
  for 
  Aeronautics 
  at 
  Langley 
  Field, 
  Va. 
  

  

  SUMMARY 
  

  

  The 
  year 
  has 
  been 
  notable 
  for 
  the 
  satisfactory 
  continuation 
  at 
  field 
  

   stations 
  of 
  observations 
  for 
  the 
  study 
  of 
  the 
  variability 
  of 
  the 
  sun; 
  

   for 
  the 
  satisfactory 
  completion 
  of 
  the 
  critical 
  statistical 
  investigation 
  

   of 
  the 
  results 
  obtained 
  at 
  Table 
  Mountain, 
  so 
  that 
  hereafter 
  Table 
  

   Mountain 
  observations 
  may 
  be 
  definitively 
  reduced 
  by 
  field 
  observers 
  ; 
  

   for 
  the 
  excellent 
  accord 
  found 
  between 
  definitive 
  results 
  of 
  Table 
  

   Mountain 
  and 
  Montezuma 
  (stations 
  4,000 
  miles 
  apart 
  in 
  opposite 
  

   hemispheres) 
  in 
  their 
  indications 
  of 
  solar 
  variability 
  ; 
  for 
  the 
  appar- 
  

   ent 
  confirmation 
  of 
  three 
  definite 
  periodicities 
  of 
  approximately 
  11, 
  

   15, 
  and 
  26 
  months 
  in 
  solar 
  variation; 
  for 
  the 
  discovery 
  of 
  a 
  new 
  

   method 
  of 
  measuring 
  the 
  atmospheric 
  ozone 
  and 
  its 
  influence 
  on 
  

   solar-constant 
  observations 
  ; 
  for 
  the 
  repetition 
  of 
  a 
  former 
  investiga- 
  

   tion 
  of 
  solar 
  and 
  terrestrial 
  absorption 
  lines 
  and 
  bands 
  in 
  the 
  solar 
  

   spectrum, 
  but 
  with 
  nearly 
  threefold 
  richer 
  results; 
  and 
  for 
  the 
  

   observation 
  of 
  the 
  distribution 
  of 
  energy 
  in 
  the 
  spectra 
  of 
  18 
  stars 
  

   and 
  two 
  planets. 
  

  

  Respectfully 
  submitted. 
  

  

  C. 
  G. 
  Abbot, 
  

   Director, 
  Astrophysical 
  Ohservatory. 
  

  

  The 
  Secretary, 
  

  

  Smithsonian 
  Institution. 
  

  

  