The main sound device is rhyme. Also, note that the accent in the verb "tenanted" is placed on the last syllable, which makes it rhime with "head". The same is done with the word "musically", in order to make it rhyme with "valley". A syllable is added to the usual pronunciation of the past participle "tuned" by placing a grave accent on it, "tunèd", for the sake of the rhythm in that verse.