And, by the incantation of this verse, Scatter, as from an unextinguished hearth Ashes and sparks, my words among mankind! (65-67)
In a comparison rather different from the running metaphor of "dead leaves," the speaker compares his ideas to "ashes and sparks," suggesting that some of them are dead and others are capable of kindling new fires.
Be through my lips to unawakened Earth The trumpet of a prophecy! (68-69)
The combination of the speaker’s mouth and the West Wind’s power will result in a "trumpet" that wakes the Earth – just as in Canto II, the metaphor here is the Last Judgment.