﻿Smithsonian 
  Report 
  1922. 
  — 
  Humphreys. 
  

  

  Plate 
  25. 
  

  

  I. 
  Crepuscular 
  Rays, 
  Seen 
  on 
  the 
  Potomac 
  River. 
  

  

  (P. 
  E. 
  Budlong, 
  photo.) 
  

  

  2. 
  Lightning, 
  Seen 
  from 
  Mount 
  Wilson, 
  Calif. 
  

  

  (F. 
  Ellerman, 
  photo.) 
  

  

  