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The National Geographic Magazine 



speed of 12 miles per hour, by its 

 screws, and a south wind is blowing at 

 10 miles per hour, the speed of the ship, 

 relative to the earth, will be 22 miles 

 per hour. Conversely, in a north wind 

 of 10 miles per hour, the ship will make 

 but 2 miles per hour. 



THE STEEL CAR 



In the accompanying illustrations the 

 reader will find the plans of the nacelle, 

 or car, of our dirigible. It is a strong 

 frame of steel tubing, and the end view 

 shows the method of its construction on 

 the truss principle. The length of this 

 nacelle, or car, is 16 meters, or 52.5 

 feet; width, outside, im. .80, or 71 

 inches; width, inside, im. .70, or 67 

 inches. 



The central section of the car is in- 

 closed by means of walls and roof of 

 fabric which is both water- and fire- 

 proof. The roof is 2 meters, or 78.5 

 inches, above the floor. The engine- 

 room is 3 m. .50, or 11.5 feet, in length, 

 and so is the cabin or living room of the 

 crew, which is also to be used as a place 

 to carry instruments and a part of the 

 provisions. One disadvantage in the 

 arrangement of the cabin is that the 

 shaft for the rear propulseur passes di- 

 rectly through it ; but it was desired to 

 have all the motors in one engine-room, 

 and hence it was not easy to make a 

 better arrangement. 



It will be noticed that the form of 

 this steel car gives it the maximum of 

 strength in proportion to its weight, 

 and that the helices, or propulseurs, 

 and their shafts are emplaced in a 

 staunch manner. The total weight of 

 the steel car, with the inclosure, but 

 without the motors, shafts, screws, or 

 any other machinery, is 330 kilos, or 

 730 pounds. 



One of the most important questions 

 that had to be decided was the power 

 and number of the motors. Should we 

 go in for high speed, or content ourselves 

 with lower speed secured with a rel- 

 atively smaller expenditure of fuel? 



Obviously this involved the whole 

 question of the plan of the campaign, 

 and the conclusion reached might be 

 decisive of the success or failure of the 

 expedition. So it may be easily under- 

 stood that many days and nights of 

 anxious study were given to this funda- 

 mental problem. 



NAVIGATING AGAINST THE WINDS 



In determination of this problem of 

 the speed the first question that arose was : 

 "Is it practicable to give the airship high 

 enough speed of its own power to enable 

 it to make headway against any winds it 

 is likely to encounter during its voyage 

 to the Pole and back?" 



If this question could be answered in 

 the affirmative — we mean in a practical, 

 not merely a theoretical, sense — then 

 manifestly this would be the better 

 method to employ. It would be fine in- 

 deed to have at one's command a ship of 

 the air, like a steamship of the ocean, that 

 need not stop its course for any wind that 

 might blow along its course, whether fav- 

 orable or unfavorable. Obviously the 

 velocities of the winds in the Arctic 

 Ocean in July and August are the criteria 

 to which this phase of the problem must 

 be first referred. Fortunately I had made 

 elaborate studies and analyses of the 

 Arctic winds. From the observations 

 made by the Dr Nansen Expedition in 

 the Pram during three years of drift 

 through the North Polar Sea, I had de- 

 duced the probabilities of winds for given 

 periods. Turning to these tables of wind 

 means or general probabilities, we found 

 that if the voyage of an aerial craft were 

 to cover a period of 10 days we might 

 expect to encounter winds as follows : 



Under 10 miles per hour — 140 hours. 



From 10 to 17 miles per hour — 80 

 hours. 



From 17 to 30 miles per hour — 20 

 hours. 



If we could equip ourselves with mo- 

 tors and screws able to secure 17 miles 

 per hour, we should be able to make 

 headway against about eleven-twelfths of 



