ROTATION AND ATMOSPHERIC DISTURBANCES GORODENSKY IG? 



The preceding expresses only the general scheme of the proposed 

 method, for in fact Ave still have to surmount numerous difficulties, 

 the more important of which are trie following: 



(i) The terrestrial surfaces separating the stations A and B 

 should be as flat .and smooth as possible, not having any high obstruc- 

 tions, in order that the air may pass freely from one station to the 

 other. For this reason we have not utilized observations of refined 

 anemometers and anemographs which are located frequently in 

 large cities and have felt obliged to rely on the observations of 

 stations of the second class in the meteorological system of Russia. 



(2) We do not generally find at station A a current of air flow- 

 ing exactly towards station B but inclined to that direction by the 

 angle /3 so that for the length of the path described by the wind 

 between the two stations it suffices to take the distance 



S = A B cos p (3) 



In fact this can only be an approximation since the trajectories of 

 the atmospheric particles are curves and not straight lines and the 

 value of 5 is larger rather than smaller than that indicated by the 

 equation (3). 



(3) The instrument by which at Russian stations we ordinarily 

 measure the direction and the velocity of the wind is a wind vane 

 placed at the summit of a mast and furnished with a suspended plate 

 of steel which by its departure from a vertical position indicates 

 the velocity of the wind. Now the iron cross-piece of this mast 

 showing the cardinal points, N., S., E., W., is often oriented inac- 

 curately and the wooden mast that carries it often acquires after 

 awhile a twist introducing an angular error anxmnting to many 

 degrees. The observations made by such a primitive apparatus 

 cannot be very exact, so that one must utilize very many of them 

 in order to eliminate these errors. 



(4) At stations of the second class the observations are made 

 at 7 a.m., 1 p.m. and 9 p.m., and consequently we do not generally 

 find at the station B any observations for the moment of time that 

 we have found by our calculation. It remains then only to make 

 a proportional interpolation between the two observations that 

 come nearest to this moment. 



As the detailed exposition of the method now proposed cannot 

 be given within the limit of this abstract we must here confine our- 

 selves to giving the results of our calculation: 



The mean value of /a for 3762 cases is found to be 



fi = 0.026 (4) 



