Dear MindReach members, I have added a new post to my series which I believe you may be interested in: Where Are the Lost Ten Tribes of Israel? The Hollow-Earth Teaching In Motion: 1852–1898, Part 5 of 10
This one documents the belief being carried by even more individuals who knew Joseph Smith personally, including Apostle and First Presidency member Willard Richards, who was also the editor of the Deseret News at the time he published his article on the topic.
Details are also given concerning the famous voyage of Fridtjof Nansen, and how the Latter-day Saints of that era watched his travels anxiously, earnestly expecting the discovery of the Lost Ten Tribes beyond the north pole.
In addition to this, the belief passed under the radar of the young James E. Talmage, later another famous Apostle; furthermore, an ordinary Elder in the Church named Frederick Culmer published a full book-length treatise arguing for the hollow earth concept at length.
These and many other intriguing sources are dealt with in detail in my post. It is becoming clearer that this belief held serious currency throughout the Church of Jesus Christ of Latter-day Saints during the 19th century.