I think the dominant irony presented in the passage would be :
The Houyhnhnms. the most rational beings on earth, are discussing the extermination of an entire group of creatures.
You can see that in this sentence, the second part of the statement contradict the statement on the first part.
The way in which Faustus uses his powers is increasingly evil.
Robert Bly’s “Counting Small-Boned Bodies” is a short poem of ten lines, written in free verse and carefully divided into four stanzas. The poem initially invites the reader to participate with the speaker (or persona) in the singular action of recounting bodies. The process Bly refers to is one of counting the bodies of enemy dead following a battle, a military practice used to determine the extent of damage inflicted on the opposing force. The satire of the poem protests the Vietnam War, and more specifically the Pentagon practice of releasing body-count statistics to the press on a daily basis. The last three stanzas show the bodies shrinking and becoming ostensibly less important. Bly uses a succession of unusual metaphoric images to demonstrate the horror of trivializing death in this manner.
Much of the effectiveness of “Counting Small-Boned Bodies” in attacking body counts as a method of measuring “progress” in the Vietnam War lies in the structure Bly develops. The poem spirals downward through ever smaller yet ever more potent images. The single line of the first stanza simply portrays the speaker’s conspiratorial approach, providing a narrative hook—inviting the reader to play along. The second line of the poem continues in the reasonable tone already established, but it proposes a connection between a real event and imaginative world where a human body could be made smaller and smaller for the sake of convenience. How the body size is reduced is never explained; however, the impact of the reduction comes in the brief third line, in which the bodies have become skull-sized. This is followed by a compelling vision of a moonlit plain filled with skulls, each representing a body. The vast numbers of skulls filling the whitened landscape is suggestive of a Romantic painting. Bly accentuates the satiric miracle of the moonlit scene by ending the stanza with an exclamation mark.
