The Bird her punctual music brings — Philomela and Procne

The Bird her punctual music brings 1
And lays it in its place-
Its place is in the Human Heart
And in the Heavenly Grace-
What respite from her thrilling toil 5
Did Beauty ever take-
But Work might be electric Rest
To those that Magic make-
(F.1556/J.1585)
[1] The Bird, punctual:: a nightingale starts to sing in the evening. her:: Philomela who changed into a nightingale in Ovid's Metamorphoses.
[3] Human Heart:: a lament usually for interpreting nightingale's song, that touches human heart.
[4] Grace:: mercy, clemency.
[5] thrilling toil:: Philomela's tongue was cut by Tereus who raped her; she wove her story in a tapestry or a robe, a thrilling toil.
[7] electric:: exciting. Rest:: a repose, halt of Procne and Philomela by Tereus' chase.
[8] Magic:: the metamorphose.

Tereus, king of Thnace, had married Procne, the daughter of Pandion king of Athens: afterwards, inflamed with lust, he deflowered Philomela, the sister of Procne, and to prevent a discovery cut out her tongue, and confined her in a hunting-seat in a wood; the injured lady wrought her story in the loom! and contrived to send the web to her sister. Procne, pretending the rites of Bacchus, attended with a female train, burst open the gates of the lodge, and carried her sister to the palace; there they killed Itys, the son of Tereus and Procne, and served him up as a feast to Iris father; when he had satiated his hunger, and called for his son, Procne told him what she had done; Philomela, at the same time, besmeared with blood, rushed into the room, and threw the head of Itys in his face. Tereus pursuing the sisters with his drawn sword was changed into a Lapwing, Procne into a Swallow, and Philomela into a Nightingale. Thus Ovid tells the story; but Aeschylus, and after him Euripides and Sophocles, represent Procne as changed into the Nightingale. ─ The Greek Tragic Theatre (1809)

They begin their song in the evening, and continue it the whole night. These their vigils did not pass unnoticed by the ancients; the slumbers of these birds were proverbial: and not to rest as much as the nightingale, expressed a very bad sleeper. ─ Elegant Extracts (1816)