AIR CURRENTS IN RELATION TO AVIATION 363 



the " ribbon " the coarseness of texture of the currents. We 

 may quote from the Wind Structure Report of the Advisory 

 Committee for Aeronautics (3) the breadth of the ribbon which 

 represents the texture at different observatories for a thirty 

 mile average wind. 



It is evident from this table and from the records upon which 

 it is based that the gustiness of wind depends upon the locality; 

 an open exposure on the sea-coast shows for sea winds the least 

 gustiness ; from an inland exposure the wind is gusty from all 

 quarters. Some examples of " ribbons " are given in fig. 14. 



The question of the variation of the gusty texture ol the 

 wind at higher levels is one to which no complete answer can 

 yet be given. For the Meteorological Office, in connection with 

 its work for the Advisory Committee, Mr. J. S. Dines (11) has 

 made out the gustiness aloft by recording the length of kite 

 wire and the variation in the pull of the wire at different heights, 

 making allowance for the effects of the long lengths of wire in 

 cushioning the variations of pull. From his results for thirty- 

 four kite ascents at Pyrton Hill we may make the following 

 rough generalisation : 



Percentage Gustiness at different Levels, taking the Gustiness 



at 0-500 ft. as 100 



