Why did Samuel Langhorne Clemens change his name to Mark Twain?
It was a term used on riverboats. The captain or the helmsman would need to know the depth of the river to prevent damage to the boat. So, they would yell “Mark twain!” and a crewman would check the depth. The mark was how deep the river was and the twain was the rope used to measure. As a youngster, Clemens worked as a crew member on several riverboats.
