﻿166 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  the 
  spectra 
  of 
  the 
  sun 
  and 
  stars, 
  and 
  many 
  of 
  the 
  details 
  which 
  have 
  

   heretofore 
  been 
  among 
  the 
  apparently 
  insoluble 
  puzzles 
  of 
  celestial 
  

   spectroscopy 
  are 
  becoming 
  clear 
  in 
  the 
  light 
  of 
  Sana's 
  expositions. 
  

   These 
  cover 
  not 
  merely 
  emission 
  but 
  absorption 
  of 
  light 
  in 
  the 
  most 
  

   striking 
  manner. 
  If 
  it 
  were 
  possible 
  to 
  express 
  these 
  in 
  language 
  

   easily 
  to 
  be 
  understood, 
  the 
  reader 
  would 
  join 
  in 
  the 
  wave 
  of 
  enthusi- 
  

   asm 
  which 
  is 
  just 
  sweeping 
  through 
  the 
  workers 
  in 
  astronomical 
  

   spectroscopy 
  and 
  kindred 
  lines 
  as 
  they 
  see 
  the 
  great 
  problems 
  of 
  

   stellar 
  evolution 
  yielding 
  to 
  laboratory 
  experiment 
  and 
  penetrating 
  

   theory. 
  

  

  