What causes Giovanni to sigh in "Rappaccini's Daughter"?

Giovanni sighs in
the opening of the story from a mixture of emotions. He is a young man for the first time out
of his sphere, so he has never been away from home before, and he is homesick. He knows the
history, or the poem, of his country, and he knows something of the history of the family
whose ancient mansion he has taken lodgings in, and he has been reminiscing about what he knows.
He remembers that one of the ancestors of the family whose crest is above the door was shown as
being in one of the circles of Hell in Dantes Inferno. He also notes that
the family is long extinct. All of this melancholy nostalgia coupled with missing his home leads
to his heavy sigh.