The Wells Cathedral clock, an astronomical clock…
1392 CE
The ornate clock, constructed at Wells, England between 1386 and 1392, employs a verge-escapement mechanism.
The dial represents the geocentric view of the universe, with sun and moon revolving round a central fixed earth.
It may be unique in showing a philosophical model of the pre-Copernican universe.
Another dial is mounted on the outside wall, driven from the same mechanism.
This is first installed in the fourteenth or fifteenth centuries, but will be restored a number of times.
The dial proposes a model of the universe.
Against a background of stars, the sun (the large gilded star on the outer ring) moves in a circle, and indicates the time using the twenty-four-hour analogue dial, which is marked in Roman numerals from I to XII, then from I to XII again.
Noon is at the top of the dial reflecting the position of the sun in the sky at this time.
In the corners, four angels hold the four cardinal winds.
These may be generating the power that makes the universe operate.
The minutes are indicated by a smaller star on the ring inside.
The inner circle shows the moon.
A pointer indicates the age of the moon, between one and thirty days.
The black and white disk above the center shows the moon's phase.
The white disk rotates once in a synodic month.
The inscription around the moon phase indicator says sphericus archetypum globus hic monstrat microcosmum, which translates as This spherical globe here shows the archetypal microcosm.
Opposite the moon circle is a weighted pivoted disc, containing a small painting of Phoebe, representing the moon.
The inscription reads: Sic peragrat Phobe, or So progresses Phoebe.
At the center of the dial, the ball represents the earth, and the clouds suggest the same.
Above the clock and to the right is a figure, known as Jack Blandifers, who hits a bell with a hammer held in his right hand and two bells hung beneath him with his heels.
A set of jousting knights also chase each other every fifteen minutes.