422 POLAR PROBLEMS 



near the ground. We flew in this way during the last part of our polar 

 flight near the coast of Alaska. However, navigation under such 

 conditions is of course dangerous and difficult. 



Our flight took place during May (May 11-14, 1926). The 

 lowest temperature was — 12.6° C, with a maximum of —10°. Future 

 flights, I therefore believe, it would be advisable to carry out one 

 month earlier. In April the fog is not so intense, and yet the temper- 

 ature is not excessively low. On the other hand we must bear in mind 

 that low temperatures, provided the ship and personnel can stand 

 them, have the advantage of making possible a heavier useful load. 



During our polar flight we found the atmosphere very calm, with 

 the exception of the first stretch, from Spitsbergen to the pole, when 

 we had a wind that sometimes reached a velocity of 25 kilometers 

 an hour. The ship was hardly ever subject to pitching and rolling. 

 For the rest of the way over the central polar area the airship did not 

 pitch or roll, and it would have been possible to land without outside 

 help. These conditions, however, were completely reversed in the 

 flight over Bering Strait, where we encountered a severe storm. 



For an airplane flying in foggy weather the danger would certainly 

 have been greater, especially in case of a forced landing, whereas a 

 dirigible is able to reduce its speed and consequently its fuel con- 

 sumption and wait for clearer weather. 



In reference to the forced landing of an airplane it must be kept 

 in mind that the surface of the ice is very uneven. This is true par- 

 ticularly about the ice ofl' the northern coast of Alaska. An airplane 

 would there have very little chance of landing safely and still less 

 chance of taking off again, because in a very short time the tides and 

 the winds modify the conformation of the ice surface. 



THE DANGER OF ICE INCRUSTATION 



Concerning the safety of traveling on a dirigible over the Arctic 

 Regions technical and scientific men in England and in Russia were 

 very doubtful and expressed their anxiety as to the possible danger of 

 a crust of ice forming over the skin of the ship, a crust so thick as to 

 force the dirigible to descend. During the trip this apprehension 

 proved to be unfounded. On the other hand, as a result of our labora- 

 tory tests in Italy, I had foreseen that provision had to be made for the 

 avoidance of this danger. Ice did form on the airship when it was 

 obliged to fly in the fog. But, while the ice incrustation was very 

 heavy on all the outer metallic parts of the ship, almost no ice formed 

 on the skin. On the whole I believe that the ice did not increase the 

 weight of the ship by more than a few hundred kilograms. 



The real danger came afterward when the ice began to drop in 

 pieces from the parts to which it was attached, and, falling in the 



