Rhetorical devices in Fredrick Douglas letter to Harriet Tubman

This question does not specify how the rhetorical devices present in this letter should be analyzed. However, we can still provide some examples that can help you complete your work:

Personification: "The midnight sky and the silent stars have been the witnesses of your devotion to freedom and of your heroism."

This is an example of personification, as Douglass talks about the sky and the stars as "witnesses." Personification occurs when an entity that is not alive is given qualities of humans.

Allusion: "Excepting John Brown – of sacred memory – I know of no one who has willingly encountered more perils and hardships to serve our enslaved people than you have."

An allusion is an indirect reference to an idea or a subject from a different context. In this case, the allusion is made to John Brown, a famous abolitionist.

Metaphor: "I have wrought in the day – you in the night."

A metaphor is a comparison in which one thing refers to another one. These comparisons tend to be unlikely. In this case, public actions are presented as the "day," while private actions are presented as the "night."

the anecdote makes readers feel sorry for the man’s lack of heritage, then reminds readers that the man has an equally valuable heritage.