An allusion is an indirect reference. Patrick Henry used allusions in his speech to connect with the representatives.When Henry states
A rhetorical question is a question that is expected not to be answered. Patrick Henry uses these device to show the representatives that what they been doing hasn't worked.For one example
Repetition is to repeat something that's been said already. Patrick Henry used repetition to get the representatives confidence and hope that they will win the war.
Imagery is used to paint a picture in someone's head.