The Nymphs, who preside over springs and rivulets, are addressed at daybreak, in honour of their several functions, and of the relations which they bear to the natural and to the moral world. Their origin is deduced from the first allegorical deities, or powers of nature, according to the doctrine of the old mythological poets, concerning the generation of the gods and the rise of things. They are then successively considered, as giving motion to the air and exciting summer breezes; as nourishing and beautifying the vegetable creation; as contributing to the fulness of navigable rivers, and consequently to the maintenance of commerce; and by that means to the maritime part of military power. Next is represented their favourable influence upon health when assisted by rural exercise, which introduces their connexion with the art of physic, and the happy effects of mineral medicinal springs. Lastly, they are celebrated for the friendship which the Muses bear them, and for the true inspiration which temperance only can receive, in opposition to the enthusiasm of the more licentious poets. O'er yonder eastern bill the twilight pale Walks forth from darkness; and the God of day, With bright Astraea seated by his side, Waits yet to leave the ocean. Tarry, Nymphs, Ye Nymphs, ye blue-eyed progeny of Thames, Who now the mazes of this rugged heath Trace with your fleeting steps; who all night long Repeat, amid the cool and tranquil air, Your lonely murmurs, tarry, and receive My offer'd lay. To pay you homage due, 10 I leave the gates of sleep; nor shall my lyre Too far into the splendid hours of morn Engage your audience; my observant hand Shall close the strain ere any sultry beam Approach you. To your subterranean haunts Ye then may timely steal; to pace with care The humid sands; to loosen from the soil The bubbling sources; to direct the rills To meet in wider channels; or beneath Some grotto's dripping arch, at height of noon 20 To slumber, shelter'd from the burning heaven.