﻿REPORT 
  OF 
  THE 
  SECRETARY 
  111 
  

  

  tion 
  of 
  all 
  Montezuma 
  observations 
  from 
  1923 
  to 
  date, 
  including 
  tlio 
  

   measurement 
  of 
  plates 
  for 
  nearly 
  150 
  days 
  of 
  fundamental 
  observa- 
  

   tion 
  by 
  Langley's 
  method, 
  and 
  also 
  the 
  setting 
  up 
  of 
  a 
  new 
  system 
  

   of 
  reduction 
  for 
  short-method 
  observations, 
  was 
  completed 
  in 
  May, 
  

   1927. 
  The 
  new 
  results, 
  while 
  differing 
  on 
  the 
  average 
  by 
  only 
  a 
  

   small 
  fraction 
  of 
  1 
  per 
  cent 
  from 
  the 
  preliminary 
  ones, 
  are 
  undoubt- 
  

   edly 
  of 
  much 
  greater 
  weight, 
  and 
  may 
  now 
  be 
  regarded 
  as 
  definitive. 
  

   A 
  full 
  description 
  of 
  the 
  processes 
  and 
  the 
  reasons 
  for 
  them 
  will 
  

   eventually 
  be 
  published. 
  

  

  A 
  similar 
  study 
  of 
  all 
  Table 
  Mountain 
  observations 
  is 
  going 
  on, 
  

   and, 
  when 
  completed, 
  definitive 
  observations 
  will 
  be 
  published 
  from 
  

   that 
  station 
  also. 
  

  

  Eeaders 
  may 
  understand 
  the 
  necessity 
  of 
  these 
  revisions 
  of 
  solar 
  

   radiation 
  observations 
  by 
  recalling 
  that 
  in 
  astronomy 
  the 
  late 
  Prof. 
  

   Lewis 
  Boss 
  spent 
  many 
  years 
  in 
  a 
  revision 
  of 
  all 
  high-class 
  observa- 
  

   tions 
  of 
  the 
  positions 
  of 
  stars, 
  and 
  introduced 
  numerous 
  correc- 
  

   tions 
  to 
  the 
  individual 
  observations, 
  based 
  on 
  extensive 
  statistical 
  

   study, 
  before 
  he 
  was 
  able 
  to 
  combine 
  the 
  whole 
  study 
  into 
  his 
  " 
  Classi- 
  

   cal 
  Preliminary 
  General 
  Catalogue." 
  A 
  similar 
  statistical 
  study 
  of 
  

   our 
  solar 
  observations 
  could 
  not 
  be 
  made 
  until 
  several 
  years 
  of 
  

   homogeneous 
  measurements 
  were 
  available. 
  It 
  would 
  have 
  been 
  bet- 
  

   ter 
  to 
  have 
  waited 
  for 
  10 
  years 
  before 
  making 
  it, 
  but 
  the 
  urgent 
  

   demands 
  of 
  meteorologists 
  for 
  our 
  solar 
  observations 
  have 
  induced 
  

   us 
  to 
  try 
  to 
  put 
  the 
  matter 
  in 
  definitive 
  form 
  thus 
  early. 
  

  

  {d) 
  Smithsonian 
  exhibition 
  of 
  February 
  11^ 
  1927. 
  — 
  In 
  connection 
  

   with 
  the 
  conference 
  of 
  eminent 
  men 
  on 
  the 
  future 
  of 
  the 
  Smithsonian 
  

   Institution, 
  the 
  Astrophysical 
  Observatory, 
  as 
  well 
  as 
  other 
  depart- 
  

   ments, 
  was 
  represented 
  by 
  an 
  exhibit 
  of 
  working 
  instruments, 
  dia- 
  

   grams, 
  and 
  photographs. 
  In 
  order 
  to 
  give 
  as 
  complete 
  and 
  striking 
  

   a 
  picture 
  as 
  possible 
  of 
  the 
  purposes 
  and 
  attainments 
  of 
  the 
  observa- 
  

   tory 
  a 
  very 
  considerable 
  amount 
  of 
  time 
  of 
  the 
  director, 
  of 
  Mr. 
  

   Aldrich, 
  and 
  of 
  Mr. 
  Kramer, 
  was 
  devoted 
  thereto. 
  

  

  FIELD 
  WORK 
  

  

  {a) 
  Table 
  Mountain., 
  Calif. 
  — 
  This 
  observatory, 
  which 
  by 
  Mr. 
  John 
  

   A. 
  Roebling's 
  generosity 
  was 
  erected 
  in 
  the 
  autumn 
  of 
  1925 
  to 
  replace 
  

   that 
  on 
  Mount 
  Harqua 
  Hala, 
  has 
  been 
  in 
  continuous 
  observation 
  of 
  

   the 
  solar 
  constant 
  of 
  radiation 
  during 
  the 
  fiscal 
  year. 
  While 
  the 
  

   number 
  of 
  days 
  available 
  for 
  observation 
  does 
  not 
  very 
  greatly 
  

   exceed 
  the 
  number 
  at 
  Harqua 
  Plala, 
  the 
  quality 
  of 
  these 
  days, 
  es- 
  

   pecially 
  in 
  the 
  months 
  of 
  June, 
  July, 
  August, 
  and 
  September, 
  is 
  

   immensely 
  superior. 
  On 
  one 
  occasion 
  in 
  the 
  autumn 
  of 
  1926 
  Mr. 
  

   Moore 
  was 
  able 
  to 
  observe 
  at 
  Table 
  Mountain 
  on 
  71 
  consecutive 
  

   days, 
  which 
  is 
  by 
  far 
  the 
  maximum 
  record 
  for 
  any 
  of 
  our 
  stations. 
  

  

  