Note 381-68 — Scene II.—The Island: before the Cell of Prospero.
Reading edition
Bermoothes is the old form of the word Bermudas. It was supposed that witches haunted the Bermudas and filled the air with tempests, which kept the waters always stormy. Still-vexed means always stormy. The present errands of the spirit Ariel are not the first he has executed for Prospero. Dew from the Bermudas was probably wanted for some of his magical rites.