292 



METEOEOLOGY AND ALLIED SUBJECTS. 



The results of the observations of tlie wind made on the last arctic ex- 

 pedition of Captain Hall have been discussed by Weihrauch. These data 

 are very valuable to the meteorologist on account of the high latitude 

 the large number of hourly observations, and the actual measurement of 

 the wind velocity instead of the ordinary estimates of wind force. The 

 distressing misfortune that befell Dr. Bessels in the employment of a 

 chief computer who proved to be wholly untrustworthy is already 

 known to meteorologists, and rendered it necessary that Weihrauch 

 should undertake the labor of an entire repetition of the computations, 

 some of the results of which are given in the following table : 



Anemometric means for Polaris Bay. 



Anemometric means for Polaris House. 



The existence of a diurnal period in the velocity is very plainly 

 shown by the observations at Polaris Bay, but less plainly by the ob- 

 servations at Polaris House, and Weihrauch remarks that there is a 

 great similarity between the diurnal period at Polaris Bay and at 

 Dorpat, Kussia. The diurnal period iu the wind direction is not plainly 

 shown for either of Captain Hall's two stations, which result is explained 

 by the fact that the observations are only recorded to the nearest eight 

 principal directions. {Z. 0. G. ili., Vol. XIV, p. 170.) 



Koppen has reviewed the important memoir published by Hann in 

 1879 on the diurnal periodicity of the wind as to velocity and direction. 

 With regard to the force of the wind, it is shown that whatever may be 

 the direction there is a diurnal periodicity in the force, such that— for 

 example, at Vienna — the times of maximum and minimum are as shown 

 in the following table : 



