Identify the italicized sound effect.

on first looking into chapman's homer

much have i travell'd in the realms of gold,

and many goodly states and kingdoms seen;

round many western islands have i been

which bards in fealty to apollo hold.

oft of one wide expanse had i been told [5]

that deep-brow'd homer ruled as his demesne;

yet did i never breathe its pure serene

till i heard chapman speak out loud and bold:

then felt i like some watcher of the skies

when a new planet swims into his ken; [10]

or like stout cortez when with eagle eyes

he star'd at the pacific–and all his men

look'd at each other with a wild surmise–

silent, upon a peak in darien.

italized word is capitalized.

answers are:

assonance

onomatopoeia

alliteration