45. Cirrus Increasing, Generally in the Form of Hooks Ending in 

 a Point or in a Small Tuft, H4. 



The streaks of cirrus in this picture have, here and there, an up- 

 turned end or a small tuft. It is stipulated that the cirrus in this code 

 classification shall increase both in time and in a certain direction, 

 but they shall not meroe into cirrostratus, which would call for code 

 Ih. (Photo on Alount^Wilson, Calif., by F. EUermann.) 



46. Cirrus, or Cirrostratus, Advancing Over the Sky But Not More 

 Than 45° Above the Horizon, H,,. 



The strands of cirrus in this picture are seen to fuse together into a 

 sheet resembling cirrostratus. The advancing front of the sheet 

 appears to be less than 45° above the horizon. In other cases, the sheet 

 may, however, be of cirrostratus without any parts definitely resembl- 

 ing cirrus. The fact that the clouds are advancmg over the sky must 

 be determined by observation. (Photo on Mount Weather, Va., by 

 A. J. Weed.) 



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