227 



From the equations, above given, we have calculated 

 a table for both instruments: 



Expeiåments. 



The anemometers were lixed in a convenient manner 

 on stånds iipon the roof of the house in Helsingfors, in 

 which the physical laboratory is located. The height of the 

 roof with the stånd was 23.5 meter. The surrounding space 

 is free in all directions, except in the west, where the tower 

 of the Nikolai-church is situated and puts a hindrance for 

 the westwind. 



During some days in January 1897 some series of ob- 

 servations were taken with a slightly different anemometer, 

 the equation of which was 



v = 0.6 3 -{- 0.4 4 n. 



The constants were determined in the same manner 

 and with the same degree of accuracy as here above men- 



