Libby Prison in Richmond was used for Union officers, and not enlisted men. Enlisted men were held at Belle Isle on an island in the James River in Richmond. Neb, as an African-American, would not have been held prisoner, but would have been sent into slavery, if taken prisoner at all. Also, there was no uniform for war correspondents, who were all civilians. The Confederates all had no observation balloons after the summer of 1862. But without all these Jules Verne would have had no story.