This work is public domain in countries where the duration is 70 years after the death of the author and in the United States (publication before 1923).
The Poison Belt was the second story, a novella, that Sir Arthur Conan Doyle wrote about Professor Challenger. Written in 1913, roughly a year before the outbreak of World War I, much of it takes place - rather oddly, given that it follows The Lost World, a story set in the jungle - in a room in Challenger's house. This would be the last story written about Challenger until the 1920s, by which time Doyle's spiritualist beliefs had begun to affect his writing.