210 



SYMPOSIUM ON AERONAUTICS. 



nrsb.ea.m. Pressure 9 a.m. 

 1033,8 I 1 i prv — 



1033,6 '■ ' - 1 /I ^ 



I033.4 



1033.2 

 .1033.0 



Fig. 21. Relation between speed, force, pressure and direction in wind gusts. 



sidered separately is a complete convective unit in which occur ap- 

 propriate changes in air pressure, temperature and in speed and di- 

 rection of movement. Fig. 21 ilkistrates a series of changes in wind 

 speed with accompanying changes in wind direction and air pressure. 

 Fig. 22 (see page 207) is a part of a record made by a pressure 

 tube anemometer showing frequency and amphtude of gusts as they 

 occur in the average westerly wind. The acceleration in the hori- 



