﻿Smithsonian 
  Report 
  1922. 
  — 
  Humphreys. 
  

  

  Plate 
  19. 
  

  

  Lenticular 
  Cloud 
  (Cumulus 
  Lenticularis), 
  Seen 
  at 
  Flagstaff, 
  Ariz. 
  

  

  (CO. 
  Lampland, 
  photo.) 
  

  

  