Vesta_, the Goddess of the hearth; here for Retirement. Saturn, as having introduced, according to the mythology, civilization, here stands for culture.
Commercing = holding communion with. Notice the accentuation.
Forget thyself to marble = forget thyself till thou are still and silent as marble.
Hist along = bring along with a hush. Hist is connected with hush.
Philomel = the nightingale.
Cynthia = the moon.
Dragon yoke. Compare "Night's swift dragons," ('Midsummer Night's Dream').
Removed place = remote or retired place. Compare "some removed ground" in 'Hamlet.'
Nightly = by night. Sometimes it means "every night successively."
Thrice-great Hermes, a translation of Hermes Trismegistus, a fabulous king of Egypt, held to be the inventor of Alchemy and Astronomy.