﻿Smithsonian 
  Report 
  1922 
  — 
  Humphreys. 
  

  

  Plate 
  8. 
  

  

  I. 
  Alto-cumulus. 
  

  

  (A. 
  J. 
  Weed 
  photo.) 
  

  

  2. 
  Billow 
  Clouds, 
  Regular 
  and 
  Irregular 
  (Forms 
  of 
  Alto-cumulus), 
  

   Over 
  Washington, 
  D. 
  C. 
  

  

  i 
  A 
  .). 
  Henry, 
  photo.) 
  

  

  