The Polar Airship 



219 



WIND FREQUENCY, DIRECTION, AND VELOCITY BY TEN-DAY PERIODS 





S.W. 



S.E. 



N.E. 



N.W. 



Calm. 



Total. 



Hours 



68 

 7-6 

 5i6 



10 

 6.5 

 65 



68 

 6.4 

 435 



94 

 7-75 

 73° 



176 



14 

 2,465 



38 

 6-5 

 245 



114 



5-5 

 630 



40 



6 



240 



76 

 8.78 

 667 



44 

 8 



352 



34 



7 



238 



126 



7-7 

 970 



38 



7-75 

 295 



80 

 9-3 



744 



102 



7-5 

 765 



82 



n.85 

 975 



146 



9 



I.3I5 



14 



240 



7-7 

 1,850 



240 



A Mean miles per hour 





2 







7.5 







i, 800 



Hours 



44 

 5-8 

 255 



8 



240 



C Mean miles per hour 



Hours 



8.16 

 1,960 



240 



Total miles 









8-5 









2,045 





46 



10 



460 



42 

 3-8 

 160 



6 



3-5 

 20 



20 



8-5 

 170 



25 25 

 7.07 

 178 



18 

 132 

 240 



92 

 7-75 

 715 



34 

 5-75 

 200 



2 



75 

 15 



43 

 7-77 

 334 





240 



E Mean miles per hour 







13.2 



Total miles 







3,165 

 240 



Hours 



48 

 7-4 

 355 



54 



5-5 

 300 



164 



20 



F Mean miles per hour 



6.4 



Total miles 





1,475 



G Mean miles per hour 



32 



240 

 5.53 



Total miles 



IA 



IJ5° 



Hours 



240 



H Mean miles per hour 



"t -r 



7 



6-94 



Total miles 



Hours 



1,150 



84.50 

 8.29 



700 



11.25 



i,575 

 240 



Total Miles per hour 



7-83 



Miles 



1,879 









Mr Wellman has assumed 10 days as the approximate duration of his aerial voy- 

 age. From the foregoing records of the actual winds (J^ram) prevailing in eight 

 such periods in July or August, it will be seen that the number of miles of wind- 

 movement divided between north and south is as follows : 



South. 



65 

 600 



73° 



North. 



982 



1,735 

 1,270 



1,315 



South. 



E 2,925 



405 



G. 

 H. 



650 

 410 



North. 



240 

 1,070 



500 

 1,165 



In only two of the eight periods is there a very great preponderance of winds 

 from one direction over those of the other. One of these has a southerly resultant, 

 the other a northerly. 



The mean of the eight periods is : South, 845 miles ; north, 1,034 miles. 



