﻿Smithsonian 
  Report 
  1922. 
  — 
  Humphreys. 
  

  

  Plate 
  II. 
  

  

  I. 
  Nimbus 
  Above, 
  Fog 
  Below; 
  Seen 
  from 
  Mount 
  Wilson, 
  Calif. 
  

  

  (F. 
  Ellerman, 
  photo.) 
  

  

  2. 
  Stratus 
  Above; 
  Fracto-stratus, 
  Scud, 
  or 
  Steam 
  

   Cloud 
  Below. 
  San 
  Gabriel 
  Range, 
  Calif. 
  

  

  