Old skiers never die, they just go downhill, explain the humor and the punning word

What language device is used in the highlighted text?

How would you write "the fourth of july? " the 4th of july or the fourth of july? are they both grammatically correct?

Fine fellow, that lebrun," said arobin when robert had gone. "i never heard you speak of him.""i knew him last summer at grand isle," she replied.  what becomes apparent during this conversation? robert and arobin are both aware they are rivals for edna’s affections.arobin is unaware of robert’s role in edna’s life, but robert is aware of arobin’s role.robert is completely unaware of arobin’s romantic intentions and love for edna.robert has much more confidence in himself than arobin does.