[443-35] Avoid means begone.
[443-36] The thin fleecy clouds, highest in the sky, were called rack.
[443-37] On is here used for of.
[443-38] We would say rounded off or finished.
[444-39] I thank ye is spoken to Ferdinand and Miranda, and is Prospero’s reply to their good wishes.
[444-40] Meet with means oppose or counteract.
[444-41] For breathing means because it breathed. In the next line, for kissing means because it kissed.
[444-42] Unback’d means unridden.
[444-43] Advanced means raised.
[445-44] The pool was mantled, or covered over, with filth.