222 



The National Geographic Magazine 



In the following interesting tables Mr Wellman has worked out his northing by 

 the navigating method already described by him in the context, for each of the 

 io-day periods covered by the Synoptic Table, on the basis of 12 miles per hour 

 motoring, for 140 hours, and retardation of 12 miles per hour during 100 hours of 

 drifting, save that in drifting with the lighter winds — 12.5, 11, 9, or even fewer 

 miles per hour — the loss is assumed at 1 mile per hour in each case. 



The first table shows what might be accomplished with all the winds throughout 

 the various periods directly contrary to the course. In two cases there would be no 

 progress at all, on account of the velocity of the contrary winds, but in all the others 

 the voyage would continue past, to, or near to the Pole. 



EXPERIENCE WITH ALL WINDS ASSUMED AS DIRECTLY UNFAVORABLE TO THE 



COURSE 



Motor period, 140 hours, 

 12 miles per hour. 1,680 

 miles. 



Mean wind. 



Miles per 



hour. 



Motor gain 



over wind. 



Miles. 



Drifting period 100 hours. 



Maximum retardation 12 miles per hour. 



Wind, miles 



per hour *g 



Drift, miles per j 



hour 1 



11 



i 



12.5 



1 



15 



3 



18 



25 



Total 

 Loss. 



6 



13 





15 



5 





90 



65 



285 



2 









12 





158 

 112 



20 







120 





252 



2 







12 





142 



7+ 



22 





444 



286 



742 



12 







72 





165 

 100 

 104 



2 







12 





130 



56 



18 





336 



234 



648 



20 







120 





232 

 112 



20 







120 





252 



38 







228 





362 



Net 

 Gain. 



485 

 647 

 608 



588 

 488 



-777 

 885 



985 

 791 



445 

 -368 

 748 

 903 

 448 



443 

 490 



6.50.... 



A 6.25 



B 6.85 



C 6.00 



D 7-5© 



E 12.25 



F 4.50. . . 



G 4.25 



H 5-75- ••■ 



1 7.90.... 

 J 10.00. . . . 

 K 5.00 



L 4-75- ••• 



M 7.00. .. 



N 6.25.... 



770 

 805 

 720 

 840 

 630 



—35 

 1,050 

 1,085 



895 

 575 

 280 

 9S0 



1,015 



700 

 805 



Hours 



Miles lost. 

 Hours 



Loss 



Hours 



Loss. ..'.., 

 Hours . . . 



Loss 



Hours 



Loss 



Hours 



Loss 



Hours . . 



Loss 



Hours 



Loss 



Hours 



Loss ...... 



Hours 



Loss 



Hours 



Loss 



Hours 



Loss 



Hours 



Loss 



Hours 



Loss 



Hours 

 Loss 



o 



o 



17 

 17 

 40 

 40 



7 

 7 

 3 

 3 



50 

 5° 



62 

 62 



23 



23 



69 



69 



9 



9 



3 



3 



25 

 25 

 21 

 21 

 36 

 36 

 13 

 13 

 39 

 39 



14 

 14 

 10 

 10 

 32 

 32 

 44 

 44 



13 



13 

 17 

 17 

 4i 

 4i 

 15 

 15 



30 

 30 

 36 

 36 

 18 

 18 

 34 

 34 

 40 

 40 



20 



20 



6 



6 



4 



4 



44 



44 



28 

 28 



25 

 75 

 24 

 72 



6 

 18 

 26 

 78 

 16 

 48 



4 

 12 



4 

 12 



2 



6 



10 



30 

 26 

 78 

 16 

 48 

 6 

 18 

 26 

 78 

 36 

 108 



Mean of the 14 10-day periods. 



♦Included with 9 miles per hour are in some cases winds of 8, 7, or 6 miles per hour. 



