In 1845, explorer John Franklin led an expedition from England to discover the Northwest Passage. Both ships were lost in the Arctic ice, leading to a decades-long search for the wreckage. Paul Watson joins us to talk about how marine science mixed with Inuit folklore lead to the discovery, which he writes about in “Ice Ghosts: The Epic Hunt for the Lost Franklin Expedition” (W.W. Norton and Co.). He’s in town for DMA Arts & Letters Live! Tuesday night at the Dallas Museum of Art.