254 



METEOROLOGY AND ALLIED SUBJECTS. 



meters. For the anemographs furnished to the German stations the 

 computed value of B is 2.396, whence their formula for computation of 

 true wind velocity is w=1.0-\-2.S96x(i. This formula has been abun- 

 dantly verified by comparison between the anemometer at the Seewarte 

 and the small normal anemometer in the possession of Professor Eeck- 

 nagel. We can, therefore, assume that the wind velocities (w), com- 

 puted for the German stations under the ordinary assumption that B=3, 

 must be reduced to true wind velocities (tc^) by the formula «;^=1.0-f 0.8 ?<;. 

 This relation may also be expressed by the following table : 



Velocity Corrected 



by German anemometers, true wind velocity. 



0.5 



1.0 



2.0 



3.0 



4.0 



5.0 



10.0 



15.0 



20.0 



25.0 



30.0 



1.4 



1.8 



2.6 



3.4 



4.2 



5.0 



9.0 



13.0 



17.0 



21.0 



25.0 



The comparison between the estimates of force made by the German 

 observers and the anemometric velocity recorded at the same stations 

 has been made by Dr. Sprung for about a thousand observations at 

 each of four stations, and the anemometric velocities can be converted 

 into true velocities by the preceding formula, as in the second and third 

 columns of the following table; and if we treat in a similar way the ob- 

 servations that were made in England and discussed by R, H. Scott, we 

 have the values given in the fourth and fifth columns of the table: 



The mean of the English and German observations' is represented 

 with considerable accuracy by the following formula, where m indi- 

 cates the scale number of the Beaufort scale : 



iv=lM -f 1.12 X w + 0.045 X n^ 



