In analyzing his observations, Hansen established that the ice drifts at a considerable angle 

 to the right of the wind (if we exclude the influence of any steady current) and he ascribed this 

 phenomenon to the deflecting force of the earth' s rotation. 



To exclude the influence of steady currents, Nansen used the following example. He pro- 

 posed that when the air particles (wind) pass over the ice in various directions they intersect 

 their own path and the ice fields (if we assume a linear relationship between the drift speed and the 

 wind speed and the absence of sea currents in the given region) should also intersect their own 

 path. From the difference in the geographical coordinates of the Fram and the time intervals be- 

 tween the return of the wind to the same point in space, Nansen calculated the direction and 

 velocity of the steady current. 



The linear relationship between the drift velocity and the wind speed was established by 

 Nansen from the following concepts. If we consider that the wind pressure on the ice is propor- 

 tional to the square of the wind speed, while the hydrodynamic resistance of the ice to motion is 

 proportional to the square of the drift velocity, during steady motion these forces should balance. 



Proceeding from these concepts, we may write mw ^ = nc^, where m and n are the co- 

 efficients of proportionality or 



m _ C 

 n ~ w, 



where a is the wind factor, c is the drift velocity and w is the wind speed. 



a 



Nansen's supposition is supported by the data of table 98, from which it is evident that the 

 wind factor did not show a dependence on wind speed. 



TABLE 98. WIND FACTOR AND THE DRIFT ANGLE ACCORD- 

 ING TO THE OBSERVATIONS OF THE FRAM 



In his final account, Nansen arrived at the results shown in table 99 for the drift of the 

 Fram from 7 November 1893 to 27 June 1896. 



To obtain the data of table 99, Nansen processed 76 drift segments in which the wind factor 

 varied from 0. 0002 to 0. 0596, on an average 0. 0182; the drift angle varied from +80° to -63°, 

 average +28°. Unfortunately, I was not able to ascertain at what height above the ice the wind 

 observations were made on the Fram. . 



357 



