Hank Morgan does it in A Connecticut Yankee in King Arthur's Court, and Ebeneezer Scrooge does it with the assistance of ghosts.
Enoch Soames sells his soul to be able to do this action, and the hunter Eckels steps on a butterfly after performing this action in Bradbury's "A Sound of Thunder." In a novel whose protagonist performs this action after being hit on the head, he becomes the Boss after predicting an eclipse, and another person who does this meets the (*) Eloi and the Morlocks. Hank Morgan does it in A Connecticut Yankee in King Arthur's Court, and Ebeneezer Scrooge does it with the assistance of ghosts. For ten points, identify this action which the Traveller builds a machine to do in an H.G. Wells novel.
Enoch Soames sells his soul to be able to do this action, and the hunter Eckels steps on a butterfly after performing this action in Bradbury's "A Sound of Thunder."
time travel (accept equivalents, also accept an answer specific to either direction like going back in time) &lt;MS&gt;