﻿Smithsonian 
  Report 
  1922.— 
  Humphreys. 
  

  

  Plate 
  4. 
  

  

  Cirrus. 
  Merging 
  into 
  Cirro-cumulus. 
  

  

  (F. 
  Ellerman, 
  photo.) 
  

  

  