Here are some other websites I found:
The Franz Josef Land Archipelago, E. B. Baldwin's Journal of the Wellman Polar Expedition, 1898-1899
VISIONS OF THE NORTH: Baldwin: Hero or Villain?
The only major and obvious historical inaccuracy I have been able to find about Evelyn Briggs Baldwin is he died in 1933 and in the Hollow Earth book he died in 1934.
I also found this website: Evelyn Briggs Baldwin Wikipedia(in Swedish)
I put it through an online translator and came up with basically this:
Evelyn Briggs Baldwin Wikipedia
Evelyn Briggs Baldwin, born July 22, 1862 in Springfield, Missouri, died October 26, 1933 in Washington, DC, was an American meteorologist and Arctic explorer.
Baldwin was a school inspector in Kansas, 1887-91 and member of the U.S. meteorological office from 1892 to 1900. He accompanied such meteorologist Robert Edwin Peary on his expedition to northern Greenland, 1893-94 and in 1897 traveled to Spitsbergen to offer Andree expedition-his service, but arrived too late. Between 1898-99 he accompanied as meteorologist Walter Well's polar expedition to Franz Josef Land, during which he discovered and explored Graham Bell Island.
In 1901 he became the leader of one of the American millionaire W. Ziegler North Pole Expedition expense, which the steamer "America" volunteer at the Franz Josef Land, where Baldwin meant at first open water penetrate to the north and passes through a slädexpedition reach the North Pole. Since the introduction of several food stores, he must be because of the heinous nature of conditions to return in August 1902.
He was later known as a lecturer and held minor posts in the U.S. Government, 1918-33. He was nearly destitute when he died in a traffic accident 1933.