The tone of "Oh Captain My Captain" is melancholy, mostly because the poem is sad and also shows peoples feelings when Abraham Lincoln died.
The poet uses words such as "father" to indicate he is talking about the father of our country, and also "object won" is saying that the war(the object) has been won.
When the poet uses the word "Captain" a image of the father of our nation, Abraham Lincoln shows up in my mind. When I see the word "ribboned wreaths" a image of the people cheering and everywhere is decorations to celebrate our victory.
The poet uses end rhyme in "Oh Captain My Captain" for example he says "My Captain does not answer, his lips are pale and still, My father does not feel my arm, he has no pulse nor will".