364 



SCIENCE PROGRESS 



The results for each level are very variable. On one occasion 

 with a westerly wind the gustiness at 1,500-2,000 ft., for example, 

 is given at 1 1 1 per cent, of that of the lower strata. But in Mr. 

 Dines's method of dealing with the records, the phenomena 

 of recurring squalls are included in the ordinary gustiness. 



Mr. Dines has also compared the records of wind at a height 

 of 98 ft. and at 35 ft., 150 yds. distant. He finds that groups of 

 gusts may be shown upon the one anemogram which have not 

 affected the other. Hence in considering the texture of wind, 

 we must distinguish between the general gustiness which is 



Record of 

 Direction. 



South. 



East. 



North. 



West. 



South. 



Fig. 13. — Record of quick run. 



more or less regular in its irregularity and the special gustiness 

 of local groups or squalls. 



An analysis of the ordinary gustiness may be shown by the 

 record of a quick run which Mr. Dines has obtained. It is 

 represented in fig. 13. The fluctuations in the wind shown on 

 the diagram are those which, with a certain reservation, we may 

 call waves. When we compare them with the waves of the 

 sea there is really little analogy. The gustiness is not regularly 

 periodic like a succession of waves and the magnitudes of its 

 excursions are equally irregular. 



