37. Altocumulus Castellatus, Mg. 



In the upper part of the picture there are horizontal bands with 

 small masses having a vertical development (altocumulus castellatus). 

 In places the small masses are reduced to thin wisps. There are also 

 some streaks of cirrus and, near the mountains in the distance, some 

 swelling cumulus clouds which would be coded io- (Photo on Mount 

 Wilson, Calif., by F. Ellermann.) 



38. Altocumulus in Scattered Cumuliform Tufts, Ms. 



In this picture, especially to the left, there are small cumuliform 

 tufts (castellatus) with a tendency toward domed upper surfaces. 

 Trails of virga appear like \\"isps of cirrus. Above and to the right 

 the clouds are brealdng up into poorly defined globular masses (Jloccus). 

 These clouds are indicative of steep lapse rates and are precursors of 

 thunderstorms. (Photo at Blue Hill Observatorv, Milton, Mass., 

 by C. F. Brooks.) 



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