"Such Sweet Compulsion Doth In Music Lie"

Context: Arcades was presented as part of an entertainment in honor of the Countess Dowager of Derby at Harefield, the roles being taken by members of her family and other scions of nobility. The "Arcades" are natives of Arcady, or Arcadia, beloved of poets. After some opening stanzas in praise of the countess, the Genius of the Wood, acted by the musician Henry Lawes, appears to tell how he cares for the trees and plants in his domain. At dawn he visits every sprout to see that it is safe and well, but during the night he gives his attention to the music of the spheres. He explains that upon each of the crystalline spheres of the eight planets and the fixed stars there sits a celestial siren who sings to the three Fates, who determine men's destinies and turn the adamant spindle, or axle, that runs through all of the crystalline spheres. The siren on each sphere sings only one note, but the combination of their notes makes the music of the spheres, heavenly music that is inaudible to mortal ears. Such music, however, is fittest to celebrate the manifold virtues of the countess. The passage derives from Plato's Vision of Er and is an explanation of the divine harmony that organizes and governs the universe. It is interesting to notice that it is Ptolemaic rather than Copernican cosmology.

. . . when drowsiness
Hath locked up mortal sense, then listen I
To the celestial Sirens' harmony,
That sit upon the nine enfolded spheres
And sing to those that hold the vital shears
And turn the adamantine spindle round,
On which the fate of gods and men is wound.
Such sweet compulsion doth in music lie,
To lull the daughters of necessity,
And keep unsteady nature to her law,
And the low world in measured motion draw
After the heavenly tune, which none can hear
Of human mold with gross unpurgèd ear.