By "the tapers" (stanza 2) is meant, I fancy, those phosphor-like fires that gather on the yard-arms of ships at sea when the air is electric with tempest. Sir Humphrey Gilbert's sailors were fearful at sight of this apparition, and of a monster, too, that appeared swimming in the waves beside their frigate, the Squirrel, a little before she and her riding lights disappeared for ever.
" ... Men which all their life time had occupied the Sea, never saw more outragious Seas. We had also upon our maine yard, an apparition of a little fire by night, which seamen doe call Castor and Pollux. But we had onely one, which they take an evill signe of more tempest.... The same Monday night, about twelve of the clocke ... suddenly her lights were out ... and withall our watch cryed, the Generall was cast away, which was too true. For in that moment, the Frigat was devoured and swallowed up of the Sea ..."
As for Cupid (stanza 5), he is said to be the slyest archer that ever shot arrow—and a dangerous child either to entertain (as the poem proves that begins as follows):
Cupid abroade was 'lated in the night,
His wings were wet with ranging in the raine;
Harbour he sought, to mee hee took his flight,
To dry his plumes I heard the boy complaine.
I opte the doore and graunted his desire,
I rose my selfe, and made the wagge a fire....