On the variations in the velocity of winds. 



Selim Lemström and J. Dannholm. 



In a paper published 1893 with the title »On the in- 

 ternal work of the wind», Mr S. P. Langley gives the re- 

 results of observations of the velocity of winds. 



The variableness of the velocity is very astonishing. 

 In a time as short as 30 to 40 seconds it can vary more 

 than 10 metres (in a second). This propriety is general, it 

 will be observed not only in strong winds, of a mean velo- 

 city from 10 to 20 metres in a second, but also in the wea- 

 kest breath of air. It seems therefore that every wind is a 

 series of puffs of varying strength. From the memory just 

 named we take the examples viz: 



Mr Langley uses his discovery to explain in a beau- 

 tiful manner the soaring flight of the birds, in proving that 

 they, so to say, rest on the gusts. Our intention is not 

 however to deal with these interesting speculations but to 

 study these variations and to see if it would not be pos- 

 sible to fmd out in them characterizing marks of the diffe- 

 rent winds. 



Though the investigation is not so advanced that a 



