That particular passage has numerous literary devices. Alliteration in the "Beams so Bright" and personification in "when Nature made Her...". The entire passage is a rhetorical question and it can be answered in he next passage with simile. Sydney answers the rhetorical question with a simile, saying her she is like a skillful painter and is like the sun. The fact that her black eyes shine bright is an oxymoron because black is dark and has no light with which to shine.
