Answer: The entire poem is an extended metaphor, or figurative language that implies comparison between seemingly unlike things, for the United States after the Civil War and Abraham Lincoln's assassination. In the metaphor, the captain is Lincoln, the voyage is the war and the ship is the United States.
<span>The adverb is "immediately". An adverb is a type of word that adds information to the verb in the sentence. The verb is the word that provides the action. So, in this sentence both "told" and "leave" are verbs, because those are actions, things that you DO. "Immediately" is describing the word "leave" and indicating HOW you need to leave.</span>