338. ~though a rush candle~, _i.e._ 'though it be only a rush-candle'; a
rush light, obtained from the pith of a rush dipped in oil.
340. ~long levelled rule~; straight horizontal beam of light: comp. _Par.
Lost_, iv. 543, "the setting sun ... _Levelled_ his evening rays." The
instrument with which straight lines are drawn is called a _rule_ or
ruler.
341. ~star of Arcady Or Tyrian Cynosure~; here put by synecdoche for
'lode-star.' More particularly, the star of Arcady signifies any of the
stars in the constellation of the Great Bear, by which Greek sailors
steered; and 'Tyrian Cynosure' signifies the stars comprising that part
of the constellation of the Lesser Bear which, from its shape, was
called _Cynosura_, the dog's tail (Greek +kynos oura+), and by which
Phoenician or Tyrian sailors steered. See _L'Alleg._ 80, "The _cynosure_
of neighbouring eyes," where the word is used as a common noun = point
of attraction. Both constellations are connected in Greek mythology with
the Arcadian nymph Callisto, who was turned by Zeus into the Great Bear
while her son Arcas became the Lesser Bear. Milton follows the Roman
poets in associating these stars with Arcadia on this account.