NO. 17.] 



BAROMETRICAL DEPRESSIONS AND THEIR MOTION. 



585 



The 10 cases in which the centre of a depression has passed over the 

 Fram give a mean duration of the passage of 3'8 days, and the following 

 directions of the motion of the centre. 



This motion agrees very well with the general motion found above. 



Taking the bearings of the least distance of the centres of depression 

 from the Fram, and grouping them according to direction and season, we 

 get the following Table, in which the numbers of cases have been reduced 

 to 8 points of the compass. 



Barometrical depressions have passed on all sides of the Fram. There 

 is a preponderance of depressions on the westerly side. In the first winter, 

 the tracks of cyclonic systems lie chiefly north of the Fram; in the second win- 

 ter, they are more evenly distributed on all sides, though those on the western 

 predominate; and in the last winter, the tracks south of the Fram are by 

 far the most frequent. The respective mean latitudes of the Fram are 79, 

 82 and 85. This seems to indicate that the general mean direction of track 



in 82 N. Lat. is nearly due East, the same result as found above. 



74 



