Letter From Birmingham Jail:
Focus on a couple paragraphs and cite where you find appeals to ethos, logos and, pathos in your COMMENT. You can randomly pick a spot in King's letter and easily find all three appeals working somewhere in the vicinity.
http://www.africa.upenn.edu/Articles_Gen/Letter_Birmingham.html
Also, use this as a reference to identify the sources of persuasion:
http://courses.durhamtech.edu/perkins/aris.html
Finally, consider how the sources of persuasion (ethos, logos, and pathos) are used (and not used) in your primary source for essay #1.