Cleanth Brooks, critic and teacher, lectured on "Yeats's Great Rooted Blossomer," a study of William Butler Yeats's “Among School Children”; Mr. Brooks stayed two days and talked to English majors and students in Aesthetics 255.   A leading proponent of the formalist “New Criticism,” Brooks published one of its primary texts, The Well Wrought Urn: Studies in the Structure of Poetry, in 1947.