While training, Samuel convinced his younger brother Henry to work with him, and even arranged a post ofmud clerkfor him on the steamboatPennsylvania. On June 13, 1858, the steamboat's boiler exploded; Henry succumbed to his wounds on June 21. Twain claimed to have foreseen this death in a dream a month earlier,[23]: 275 which inspired his interest in parapsychology; he was an early member of the Society for Psychical Research.
