The reason why I have gone into so many details regarding this side of our plans and our conduct of the expedition, is that we have been publicly criticized “because we flew with _two_ machines over a stretch of territory that offered no landing possibilities, and thus we took a _double_ risk of engine trouble.” This is putting a wrong construction on it. The reason that we continued our northward flight after we had reached 83°, and, being free of the fog, saw that there were only bad chances of landing, was because we naturally had a goal to reach and we thought conditions would improve further north. Back to the choice of type! In clear weather, especially in sunshine, one can see from overhead unevennesses on a place, even when one cannot be certain that all is clear, as the snow may have “covered-in” some banks of drift-ice. If the weather is hazy, even a voluntary landing is a matter of chance, for it is impossible to see even the biggest undulations in the snow. There are three kinds of under-carriages to choose from--skis, floats, or flying boats. If one has chosen skis or floats, and should strike against a projection with them, tearing off the under part, the machine will turn over, and a continuation of the flight with the same machine will be impossible. A flying boat on the contrary has fewer sidewise projections (which means that it would be less exposed to the danger of being damaged by unevennesses) and, furthermore, it will not capsize so quickly. If one has also ordered it of durable aluminium it will afford the uttermost safety. Where a big strain would tear the bottom of a wooden boat (making reparation impossible or at least very difficult in the conditions prevailing up there) under the same strain durable aluminium would only suffer some denting which could be straightened out again if it proved sufficient to hinder progress. Aluminium does not break easily. There were also other reasons that counted in making the choice of a type of boat. Should one have the intention of rising from deep snow, the burden (of the boat or the machine’s under-carriage) lying on the snow must not be greater than a certain weight on the flat, namely, 600 kilograms per square meter. As our machine would average a weight of six tons it was a simple matter to calculate that we must lie on an area of at least ten square yards, and even then it would be bearing the maximum weight. Thus, a ski-attachment would be particularly heavy, and the floats would have to be unnecessarily large if the bottom’s lines were to satisfy the seamanlike desire “to rise from the water.” After making these calculations we were never in doubt, but decided that we should choose a flying boat built of durable aluminium. With regard to ski-machines, we should gain a further advantage in being able to land in, or rise from, possible water-lanes, while in a wooden boat a collision with ice in the water-lanes presented a smaller risk.