The Sun in reigning to the West — Holy Yoke

The Sun in reigning to the West 1
Makes not as much of sound
As Cart of man in road below
Adroitly turning round
That Whiffletree of Amethyst
(F.1656/J.1636)
[1] Sun:: the glory of Christian; or Helios the Sun god. the West:: the setting of sun, the declining.
[2] sound:: a swoon or fainting-fit (OED n.4).
[3] Cart of man:: the load of human.
[4] turning round:: without touching the core, and falling into a sound.
[5] Whiffletree:: a crossbar linked horses and carriage. Whiffletree of Amethyst:: a holy yoke on human.