Final answer:
William Lloyd Garrison uses ethos in the excerpt from 'To the Public' by referencing the Declaration of Independence and aligning his call for the immediate enfranchisement of slaves with the document's authority on equality.
Step-by-step explanation:
In the excerpt from "To the Public" by William Lloyd Garrison, the type of rhetorical appeal used is ethos. Garrison references the Declaration of Independence, espousing the 'self-evident truth' that 'all men are created equal'. By invoking the authority of the Declaration and aligning his argument with this revered document, Garrison establishes his credibility and ethical stance on the issue of slavery, thereby employing ethos. He connects the American foundational ideal of equality to his argument for the immediate enfranchisement of slaves as a moral imperative, which also has aspects of pathos given its emotional weight concerning the rights of the enslaved population.