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.