By a departing light — Sting Ray

By a departing light
We see acuter, quite,
Than by a wick that stays.
There's something in the flight
That clarifies the sight
And decks the rays.
(F.1749/J.1714)
[1] light:: softly, gently.
[3] wick:: a cord or bundle of threads, indicating the sting ray's tail.
[6] ray:: a broad flat fish with a narrow tail, a skate.