By the end of World War I, about five percent of the Antarctic landmass had been explored. A small wedge from the Ross Ice Shelf to the South Pole was the only area of the vast interior impressed by a human footprint, and less than one third of the coastline had been sighted. During the 1920s and 1930s, as new areas were added to maps, inaccurate names were sometimes assigned to them. For example, in 1928, when Sir Hubert Wilkins flew along what we now call the Antarctic Peninsula, he incorrectly reported it to be a series of islands. As a result, maps of the period showed it as the “Antarctic Archipelago.” (The northern section was known as Graham Land and the southern section as Palmer Land.) In other cases, names were assigned, then altered as areas underwent more definitive mapping, or mapmakers chose to be more concise. Hearst Land moved and became Hearst Island. James W. Ellsworth Land was, for a period, Ellsworth Highland and is now simply Ellsworth Land. For consistency with quoted passages and maps, I generally adopt the names the explorers used, only offering an explanation when necessary to avoid confusion. I have also included maps, showing the known areas of Antarctica at the commencement of the Ellsworth expeditions, along with Wilkins’s map of the Antarctic Archipelago drawn in 1930.
Navigation held special difficulties for polar aviators during the 1930s. Their instruments and methods were evolving from those used by mariners, who took sextant readings at sea level. So in addition to the difficulties associated with traveling at a much higher speed, navigators cramped in a cockpit also had to estimate their altitude, which was problematic over unexplored land, where the heights of mountains were unknown. Also, mariners sailed in lower latitudes, where meridians of longitude are farther apart and magnetic compass variation is less acute. Because I didn’t want to slow the narrative with lengthy explanations, an overview of the methods employed by Lincoln Ellsworth to cross Antarctica is included as an appendix, along with the instructions, estimated positions, and compass variations for the flight, as compiled by Sir Hubert Wilkins.
For period authenticity, I have usually retained the terms and expressions that were used by the explorers. Hence, distances are in miles, length in feet and inches, and weights are generally quoted using imperial measures. The only exception to the use of imperial measures are gallons, which are U.S. I include the metric equivalent to weights, capacity, and distance where I feel it may assist understanding. Unless otherwise stated, miles are statute rather than nautical.