[451-4] In this place all has the sense of quite; relish means feel; passion has the sense of suffering. The meaning of the clause is, that feel suffering quite as sharply as they.
[451-5] Neptune, the name of the god of the seas, is used for sea or ocean.
[451-6] “Fairy rings” are green circles in the grass. They were supposed to be caused by fairies dancing in a circle, but are now known to be caused by mushrooms which grow in circles and which enrich the ground as they decay. Because it contained some peculiar quality which Shakespeare calls sourness, the sheep would not eat the grass of the rings.
[452-7] Because mushrooms and toadstools spring up so quickly in the night, they were supposed to be the work of fairies.
[452-8] The curfew rings at night, and the fairies rejoice to hear it, for it is the signal for them to begin their frolics.
[452-9] The fairies are weak masters, that is, they can accomplish little if left to themselves, but under the direction of a human mind like Prospero’s they could work such wonders as he describes.
[452-10] The oak was sacred to Jove (Jupiter), and lightning and thunder-bolts were his chief weapons.
[452-11] The spurs are the long roots of the pines and cedars.
[453-12] Boil’d is used for boiling or seething.
[453-13] Sociable to means sympathizing with.