One of the original concepts of the clock was to show the passing of time on a longer scale than human life. The hand of Jupiter takes 4330 days, 14 hours and 38 minutes to travel once round the dial. This it does in an anti-clockwise direction, as this is the direction the solar system actually travels. The motto etched in the circumference of the scale reads: "Jupiter's orbit is 4330 days, 14 hours and 38 minutes. Its hand passes the present point 5.9 times during three score years and ten."
The base plate of the dial is glass, allowing all movement to be observed. The left hand upper dial shows the sun travelling through the sky, its time of rising and setting being shown by a rising and falling shutter, on which the constellation of Orion is displayed. As the year progresses the plate falls thus showing an earlier sunrise time, and allows the sun to appear sooner in the scale. The time of the sunset is also extended - so the sun sets later. As autumn approaches the shutter is well on the way up again, until at the winter solstice the shutter is fully raised, and Orion is fully visible. The right hand upper scale shows the phase of the moon. The sphere is silver, with the dark side being guilder. The lunar day is engraved in a band round the "equator" of the moon. The lunar month is shown in the revolving scale, which travels anti-clockwise. Situated between the two scales, and slightly lower, is the calendar disc. This disc displays the date, and the angle of the sun in the sky over London, at mid-day. This is a detail specifically requested by our client.
An alternative feature is to display the equation of time, as on clock number 19. The remaining two scales are situated in the lower corners of the dial. Both the hands are levers to be turned by hand to carry out the following operations: The left hand side is to allow the clock to be regulated without stopping the pendulum. The right hand side is for turning the striking on and off, allowing light sleepers to sleep through the night!